1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "method_verifier-inl.h"
18 
19 #include <iostream>
20 
21 #include "art_field-inl.h"
22 #include "art_method-inl.h"
23 #include "base/logging.h"
24 #include "base/mutex-inl.h"
25 #include "base/stl_util.h"
26 #include "base/systrace.h"
27 #include "base/time_utils.h"
28 #include "class_linker.h"
29 #include "compiler_callbacks.h"
30 #include "dex_file-inl.h"
31 #include "dex_instruction-inl.h"
32 #include "dex_instruction_utils.h"
33 #include "dex_instruction_visitor.h"
34 #include "experimental_flags.h"
35 #include "gc/accounting/card_table-inl.h"
36 #include "indenter.h"
37 #include "intern_table.h"
38 #include "leb128.h"
39 #include "mirror/class.h"
40 #include "mirror/class-inl.h"
41 #include "mirror/dex_cache-inl.h"
42 #include "mirror/object-inl.h"
43 #include "mirror/object_array-inl.h"
44 #include "reg_type-inl.h"
45 #include "register_line-inl.h"
46 #include "runtime.h"
47 #include "scoped_thread_state_change.h"
48 #include "utils.h"
49 #include "handle_scope-inl.h"
50 
51 namespace art {
52 namespace verifier {
53 
54 static constexpr bool kTimeVerifyMethod = !kIsDebugBuild;
55 static constexpr bool kDebugVerify = false;
56 // TODO: Add a constant to method_verifier to turn on verbose logging?
57 
58 // On VLOG(verifier), should we dump the whole state when we run into a hard failure?
59 static constexpr bool kDumpRegLinesOnHardFailureIfVLOG = true;
60 
61 // We print a warning blurb about "dx --no-optimize" when we find monitor-locking issues. Make
62 // sure we only print this once.
63 static bool gPrintedDxMonitorText = false;
64 
PcToRegisterLineTable(ScopedArenaAllocator & arena)65 PcToRegisterLineTable::PcToRegisterLineTable(ScopedArenaAllocator& arena)
66     : register_lines_(arena.Adapter(kArenaAllocVerifier)) {}
67 
Init(RegisterTrackingMode mode,InstructionFlags * flags,uint32_t insns_size,uint16_t registers_size,MethodVerifier * verifier)68 void PcToRegisterLineTable::Init(RegisterTrackingMode mode, InstructionFlags* flags,
69                                  uint32_t insns_size, uint16_t registers_size,
70                                  MethodVerifier* verifier) {
71   DCHECK_GT(insns_size, 0U);
72   register_lines_.resize(insns_size);
73   for (uint32_t i = 0; i < insns_size; i++) {
74     bool interesting = false;
75     switch (mode) {
76       case kTrackRegsAll:
77         interesting = flags[i].IsOpcode();
78         break;
79       case kTrackCompilerInterestPoints:
80         interesting = flags[i].IsCompileTimeInfoPoint() || flags[i].IsBranchTarget();
81         break;
82       case kTrackRegsBranches:
83         interesting = flags[i].IsBranchTarget();
84         break;
85       default:
86         break;
87     }
88     if (interesting) {
89       register_lines_[i].reset(RegisterLine::Create(registers_size, verifier));
90     }
91   }
92 }
93 
~PcToRegisterLineTable()94 PcToRegisterLineTable::~PcToRegisterLineTable() {}
95 
96 // Note: returns true on failure.
FailOrAbort(MethodVerifier * verifier,bool condition,const char * error_msg,uint32_t work_insn_idx)97 ALWAYS_INLINE static inline bool FailOrAbort(MethodVerifier* verifier, bool condition,
98                                              const char* error_msg, uint32_t work_insn_idx) {
99   if (kIsDebugBuild) {
100     // In a debug build, abort if the error condition is wrong.
101     DCHECK(condition) << error_msg << work_insn_idx;
102   } else {
103     // In a non-debug build, just fail the class.
104     if (!condition) {
105       verifier->Fail(VERIFY_ERROR_BAD_CLASS_HARD) << error_msg << work_insn_idx;
106       return true;
107     }
108   }
109 
110   return false;
111 }
112 
SafelyMarkAllRegistersAsConflicts(MethodVerifier * verifier,RegisterLine * reg_line)113 static void SafelyMarkAllRegistersAsConflicts(MethodVerifier* verifier, RegisterLine* reg_line) {
114   if (verifier->IsInstanceConstructor()) {
115     // Before we mark all regs as conflicts, check that we don't have an uninitialized this.
116     reg_line->CheckConstructorReturn(verifier);
117   }
118   reg_line->MarkAllRegistersAsConflicts(verifier);
119 }
120 
VerifyClass(Thread * self,mirror::Class * klass,CompilerCallbacks * callbacks,bool allow_soft_failures,LogSeverity log_level,std::string * error)121 MethodVerifier::FailureKind MethodVerifier::VerifyClass(Thread* self,
122                                                         mirror::Class* klass,
123                                                         CompilerCallbacks* callbacks,
124                                                         bool allow_soft_failures,
125                                                         LogSeverity log_level,
126                                                         std::string* error) {
127   if (klass->IsVerified()) {
128     return kNoFailure;
129   }
130   bool early_failure = false;
131   std::string failure_message;
132   const DexFile& dex_file = klass->GetDexFile();
133   const DexFile::ClassDef* class_def = klass->GetClassDef();
134   mirror::Class* super = klass->GetSuperClass();
135   std::string temp;
136   if (super == nullptr && strcmp("Ljava/lang/Object;", klass->GetDescriptor(&temp)) != 0) {
137     early_failure = true;
138     failure_message = " that has no super class";
139   } else if (super != nullptr && super->IsFinal()) {
140     early_failure = true;
141     failure_message = " that attempts to sub-class final class " + PrettyDescriptor(super);
142   } else if (class_def == nullptr) {
143     early_failure = true;
144     failure_message = " that isn't present in dex file " + dex_file.GetLocation();
145   }
146   if (early_failure) {
147     *error = "Verifier rejected class " + PrettyDescriptor(klass) + failure_message;
148     if (callbacks != nullptr) {
149       ClassReference ref(&dex_file, klass->GetDexClassDefIndex());
150       callbacks->ClassRejected(ref);
151     }
152     return kHardFailure;
153   }
154   StackHandleScope<2> hs(self);
155   Handle<mirror::DexCache> dex_cache(hs.NewHandle(klass->GetDexCache()));
156   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(klass->GetClassLoader()));
157   return VerifyClass(self,
158                      &dex_file,
159                      dex_cache,
160                      class_loader,
161                      class_def,
162                      callbacks,
163                      allow_soft_failures,
164                      log_level,
165                      error);
166 }
167 
168 template <bool kDirect>
HasNextMethod(ClassDataItemIterator * it)169 static bool HasNextMethod(ClassDataItemIterator* it) {
170   return kDirect ? it->HasNextDirectMethod() : it->HasNextVirtualMethod();
171 }
172 
FailureKindMax(MethodVerifier::FailureKind fk1,MethodVerifier::FailureKind fk2)173 static MethodVerifier::FailureKind FailureKindMax(MethodVerifier::FailureKind fk1,
174                                                   MethodVerifier::FailureKind fk2) {
175   static_assert(MethodVerifier::FailureKind::kNoFailure <
176                     MethodVerifier::FailureKind::kSoftFailure
177                 && MethodVerifier::FailureKind::kSoftFailure <
178                        MethodVerifier::FailureKind::kHardFailure,
179                 "Unexpected FailureKind order");
180   return std::max(fk1, fk2);
181 }
182 
Merge(const MethodVerifier::FailureData & fd)183 void MethodVerifier::FailureData::Merge(const MethodVerifier::FailureData& fd) {
184   kind = FailureKindMax(kind, fd.kind);
185   types |= fd.types;
186 }
187 
188 template <bool kDirect>
VerifyMethods(Thread * self,ClassLinker * linker,const DexFile * dex_file,const DexFile::ClassDef * class_def,ClassDataItemIterator * it,Handle<mirror::DexCache> dex_cache,Handle<mirror::ClassLoader> class_loader,CompilerCallbacks * callbacks,bool allow_soft_failures,LogSeverity log_level,bool need_precise_constants,std::string * error_string)189 MethodVerifier::FailureData MethodVerifier::VerifyMethods(Thread* self,
190                                                           ClassLinker* linker,
191                                                           const DexFile* dex_file,
192                                                           const DexFile::ClassDef* class_def,
193                                                           ClassDataItemIterator* it,
194                                                           Handle<mirror::DexCache> dex_cache,
195                                                           Handle<mirror::ClassLoader> class_loader,
196                                                           CompilerCallbacks* callbacks,
197                                                           bool allow_soft_failures,
198                                                           LogSeverity log_level,
199                                                           bool need_precise_constants,
200                                                           std::string* error_string) {
201   DCHECK(it != nullptr);
202 
203   MethodVerifier::FailureData failure_data;
204 
205   int64_t previous_method_idx = -1;
206   while (HasNextMethod<kDirect>(it)) {
207     self->AllowThreadSuspension();
208     uint32_t method_idx = it->GetMemberIndex();
209     if (method_idx == previous_method_idx) {
210       // smali can create dex files with two encoded_methods sharing the same method_idx
211       // http://code.google.com/p/smali/issues/detail?id=119
212       it->Next();
213       continue;
214     }
215     previous_method_idx = method_idx;
216     InvokeType type = it->GetMethodInvokeType(*class_def);
217     ArtMethod* method = linker->ResolveMethod<ClassLinker::kNoICCECheckForCache>(
218         *dex_file, method_idx, dex_cache, class_loader, nullptr, type);
219     if (method == nullptr) {
220       DCHECK(self->IsExceptionPending());
221       // We couldn't resolve the method, but continue regardless.
222       self->ClearException();
223     } else {
224       DCHECK(method->GetDeclaringClassUnchecked() != nullptr) << type;
225     }
226     StackHandleScope<1> hs(self);
227     std::string hard_failure_msg;
228     MethodVerifier::FailureData result = VerifyMethod(self,
229                                                       method_idx,
230                                                       dex_file,
231                                                       dex_cache,
232                                                       class_loader,
233                                                       class_def,
234                                                       it->GetMethodCodeItem(),
235                                                       method,
236                                                       it->GetMethodAccessFlags(),
237                                                       callbacks,
238                                                       allow_soft_failures,
239                                                       log_level,
240                                                       need_precise_constants,
241                                                       &hard_failure_msg);
242     if (result.kind == kHardFailure) {
243       if (failure_data.kind == kHardFailure) {
244         // If we logged an error before, we need a newline.
245         *error_string += "\n";
246       } else {
247         // If we didn't log a hard failure before, print the header of the message.
248         *error_string += "Verifier rejected class ";
249         *error_string += PrettyDescriptor(dex_file->GetClassDescriptor(*class_def));
250         *error_string += ":";
251       }
252       *error_string += " ";
253       *error_string += hard_failure_msg;
254     }
255     failure_data.Merge(result);
256     it->Next();
257   }
258 
259   return failure_data;
260 }
261 
VerifyClass(Thread * self,const DexFile * dex_file,Handle<mirror::DexCache> dex_cache,Handle<mirror::ClassLoader> class_loader,const DexFile::ClassDef * class_def,CompilerCallbacks * callbacks,bool allow_soft_failures,LogSeverity log_level,std::string * error)262 MethodVerifier::FailureKind MethodVerifier::VerifyClass(Thread* self,
263                                                         const DexFile* dex_file,
264                                                         Handle<mirror::DexCache> dex_cache,
265                                                         Handle<mirror::ClassLoader> class_loader,
266                                                         const DexFile::ClassDef* class_def,
267                                                         CompilerCallbacks* callbacks,
268                                                         bool allow_soft_failures,
269                                                         LogSeverity log_level,
270                                                         std::string* error) {
271   DCHECK(class_def != nullptr);
272   ScopedTrace trace(__FUNCTION__);
273 
274   // A class must not be abstract and final.
275   if ((class_def->access_flags_ & (kAccAbstract | kAccFinal)) == (kAccAbstract | kAccFinal)) {
276     *error = "Verifier rejected class ";
277     *error += PrettyDescriptor(dex_file->GetClassDescriptor(*class_def));
278     *error += ": class is abstract and final.";
279     return kHardFailure;
280   }
281 
282   const uint8_t* class_data = dex_file->GetClassData(*class_def);
283   if (class_data == nullptr) {
284     // empty class, probably a marker interface
285     return kNoFailure;
286   }
287   ClassDataItemIterator it(*dex_file, class_data);
288   while (it.HasNextStaticField() || it.HasNextInstanceField()) {
289     it.Next();
290   }
291   ClassLinker* linker = Runtime::Current()->GetClassLinker();
292   // Direct methods.
293   MethodVerifier::FailureData data1 = VerifyMethods<true>(self,
294                                                           linker,
295                                                           dex_file,
296                                                           class_def,
297                                                           &it,
298                                                           dex_cache,
299                                                           class_loader,
300                                                           callbacks,
301                                                           allow_soft_failures,
302                                                           log_level,
303                                                           false /* need precise constants */,
304                                                           error);
305   // Virtual methods.
306   MethodVerifier::FailureData data2 = VerifyMethods<false>(self,
307                                                            linker,
308                                                            dex_file,
309                                                            class_def,
310                                                            &it,
311                                                            dex_cache,
312                                                            class_loader,
313                                                            callbacks,
314                                                            allow_soft_failures,
315                                                            log_level,
316                                                            false /* need precise constants */,
317                                                            error);
318 
319   data1.Merge(data2);
320 
321   if (data1.kind == kNoFailure) {
322     return kNoFailure;
323   } else {
324     if ((data1.types & VERIFY_ERROR_LOCKING) != 0) {
325       // Print a warning about expected slow-down. Use a string temporary to print one contiguous
326       // warning.
327       std::string tmp =
328           StringPrintf("Class %s failed lock verification and will run slower.",
329                        PrettyDescriptor(dex_file->GetClassDescriptor(*class_def)).c_str());
330       if (!gPrintedDxMonitorText) {
331         tmp = tmp + "\nCommon causes for lock verification issues are non-optimized dex code\n"
332                     "and incorrect proguard optimizations.";
333         gPrintedDxMonitorText = true;
334       }
335       LOG(WARNING) << tmp;
336     }
337     return data1.kind;
338   }
339 }
340 
IsLargeMethod(const DexFile::CodeItem * const code_item)341 static bool IsLargeMethod(const DexFile::CodeItem* const code_item) {
342   if (code_item == nullptr) {
343     return false;
344   }
345 
346   uint16_t registers_size = code_item->registers_size_;
347   uint32_t insns_size = code_item->insns_size_in_code_units_;
348 
349   return registers_size * insns_size > 4*1024*1024;
350 }
351 
VerifyMethod(Thread * self,uint32_t method_idx,const DexFile * dex_file,Handle<mirror::DexCache> dex_cache,Handle<mirror::ClassLoader> class_loader,const DexFile::ClassDef * class_def,const DexFile::CodeItem * code_item,ArtMethod * method,uint32_t method_access_flags,CompilerCallbacks * callbacks,bool allow_soft_failures,LogSeverity log_level,bool need_precise_constants,std::string * hard_failure_msg)352 MethodVerifier::FailureData MethodVerifier::VerifyMethod(Thread* self,
353                                                          uint32_t method_idx,
354                                                          const DexFile* dex_file,
355                                                          Handle<mirror::DexCache> dex_cache,
356                                                          Handle<mirror::ClassLoader> class_loader,
357                                                          const DexFile::ClassDef* class_def,
358                                                          const DexFile::CodeItem* code_item,
359                                                          ArtMethod* method,
360                                                          uint32_t method_access_flags,
361                                                          CompilerCallbacks* callbacks,
362                                                          bool allow_soft_failures,
363                                                          LogSeverity log_level,
364                                                          bool need_precise_constants,
365                                                          std::string* hard_failure_msg) {
366   MethodVerifier::FailureData result;
367   uint64_t start_ns = kTimeVerifyMethod ? NanoTime() : 0;
368 
369   MethodVerifier verifier(self,
370                           dex_file,
371                           dex_cache,
372                           class_loader,
373                           class_def,
374                           code_item,
375                           method_idx,
376                           method,
377                           method_access_flags,
378                           true /* can_load_classes */,
379                           allow_soft_failures,
380                           need_precise_constants,
381                           false /* verify to dump */,
382                           true /* allow_thread_suspension */);
383   if (verifier.Verify()) {
384     // Verification completed, however failures may be pending that didn't cause the verification
385     // to hard fail.
386     CHECK(!verifier.have_pending_hard_failure_);
387 
388     if (code_item != nullptr && callbacks != nullptr) {
389       // Let the interested party know that the method was verified.
390       callbacks->MethodVerified(&verifier);
391     }
392 
393     if (verifier.failures_.size() != 0) {
394       if (VLOG_IS_ON(verifier)) {
395         verifier.DumpFailures(VLOG_STREAM(verifier) << "Soft verification failures in "
396                                                     << PrettyMethod(method_idx, *dex_file) << "\n");
397       }
398       result.kind = kSoftFailure;
399       if (method != nullptr &&
400           !CanCompilerHandleVerificationFailure(verifier.encountered_failure_types_)) {
401         method->SetAccessFlags(method->GetAccessFlags() | kAccCompileDontBother);
402       }
403     }
404     if (method != nullptr) {
405       if (verifier.HasInstructionThatWillThrow()) {
406         method->SetAccessFlags(method->GetAccessFlags() | kAccCompileDontBother);
407       }
408       if ((verifier.encountered_failure_types_ & VerifyError::VERIFY_ERROR_LOCKING) != 0) {
409         method->SetAccessFlags(method->GetAccessFlags() | kAccMustCountLocks);
410       }
411     }
412   } else {
413     // Bad method data.
414     CHECK_NE(verifier.failures_.size(), 0U);
415 
416     if (UNLIKELY(verifier.have_pending_experimental_failure_)) {
417       // Failed due to being forced into interpreter. This is ok because
418       // we just want to skip verification.
419       result.kind = kSoftFailure;
420     } else {
421       CHECK(verifier.have_pending_hard_failure_);
422       if (VLOG_IS_ON(verifier)) {
423         log_level = LogSeverity::VERBOSE;
424       }
425       if (log_level > LogSeverity::VERBOSE) {
426         verifier.DumpFailures(LOG(log_level) << "Verification error in "
427                                              << PrettyMethod(method_idx, *dex_file) << "\n");
428       }
429       if (hard_failure_msg != nullptr) {
430         CHECK(!verifier.failure_messages_.empty());
431         *hard_failure_msg =
432             verifier.failure_messages_[verifier.failure_messages_.size() - 1]->str();
433       }
434       result.kind = kHardFailure;
435 
436       if (callbacks != nullptr) {
437         // Let the interested party know that we failed the class.
438         ClassReference ref(dex_file, dex_file->GetIndexForClassDef(*class_def));
439         callbacks->ClassRejected(ref);
440       }
441     }
442     if (VLOG_IS_ON(verifier)) {
443       std::cout << "\n" << verifier.info_messages_.str();
444       verifier.Dump(std::cout);
445     }
446   }
447   if (kTimeVerifyMethod) {
448     uint64_t duration_ns = NanoTime() - start_ns;
449     if (duration_ns > MsToNs(100)) {
450       LOG(WARNING) << "Verification of " << PrettyMethod(method_idx, *dex_file)
451                    << " took " << PrettyDuration(duration_ns)
452                    << (IsLargeMethod(code_item) ? " (large method)" : "");
453     }
454   }
455   result.types = verifier.encountered_failure_types_;
456   return result;
457 }
458 
VerifyMethodAndDump(Thread * self,VariableIndentationOutputStream * vios,uint32_t dex_method_idx,const DexFile * dex_file,Handle<mirror::DexCache> dex_cache,Handle<mirror::ClassLoader> class_loader,const DexFile::ClassDef * class_def,const DexFile::CodeItem * code_item,ArtMethod * method,uint32_t method_access_flags)459 MethodVerifier* MethodVerifier::VerifyMethodAndDump(Thread* self,
460                                                     VariableIndentationOutputStream* vios,
461                                                     uint32_t dex_method_idx,
462                                                     const DexFile* dex_file,
463                                                     Handle<mirror::DexCache> dex_cache,
464                                                     Handle<mirror::ClassLoader> class_loader,
465                                                     const DexFile::ClassDef* class_def,
466                                                     const DexFile::CodeItem* code_item,
467                                                     ArtMethod* method,
468                                                     uint32_t method_access_flags) {
469   MethodVerifier* verifier = new MethodVerifier(self,
470                                                 dex_file,
471                                                 dex_cache,
472                                                 class_loader,
473                                                 class_def,
474                                                 code_item,
475                                                 dex_method_idx,
476                                                 method,
477                                                 method_access_flags,
478                                                 true /* can_load_classes */,
479                                                 true /* allow_soft_failures */,
480                                                 true /* need_precise_constants */,
481                                                 true /* verify_to_dump */,
482                                                 true /* allow_thread_suspension */);
483   verifier->Verify();
484   verifier->DumpFailures(vios->Stream());
485   vios->Stream() << verifier->info_messages_.str();
486   // Only dump and return if no hard failures. Otherwise the verifier may be not fully initialized
487   // and querying any info is dangerous/can abort.
488   if (verifier->have_pending_hard_failure_) {
489     delete verifier;
490     return nullptr;
491   } else {
492     verifier->Dump(vios);
493     return verifier;
494   }
495 }
496 
MethodVerifier(Thread * self,const DexFile * dex_file,Handle<mirror::DexCache> dex_cache,Handle<mirror::ClassLoader> class_loader,const DexFile::ClassDef * class_def,const DexFile::CodeItem * code_item,uint32_t dex_method_idx,ArtMethod * method,uint32_t method_access_flags,bool can_load_classes,bool allow_soft_failures,bool need_precise_constants,bool verify_to_dump,bool allow_thread_suspension)497 MethodVerifier::MethodVerifier(Thread* self,
498                                const DexFile* dex_file,
499                                Handle<mirror::DexCache> dex_cache,
500                                Handle<mirror::ClassLoader> class_loader,
501                                const DexFile::ClassDef* class_def,
502                                const DexFile::CodeItem* code_item,
503                                uint32_t dex_method_idx,
504                                ArtMethod* method,
505                                uint32_t method_access_flags,
506                                bool can_load_classes,
507                                bool allow_soft_failures,
508                                bool need_precise_constants,
509                                bool verify_to_dump,
510                                bool allow_thread_suspension)
511     : self_(self),
512       arena_stack_(Runtime::Current()->GetArenaPool()),
513       arena_(&arena_stack_),
514       reg_types_(can_load_classes, arena_),
515       reg_table_(arena_),
516       work_insn_idx_(DexFile::kDexNoIndex),
517       dex_method_idx_(dex_method_idx),
518       mirror_method_(method),
519       method_access_flags_(method_access_flags),
520       return_type_(nullptr),
521       dex_file_(dex_file),
522       dex_cache_(dex_cache),
523       class_loader_(class_loader),
524       class_def_(class_def),
525       code_item_(code_item),
526       declaring_class_(nullptr),
527       interesting_dex_pc_(-1),
528       monitor_enter_dex_pcs_(nullptr),
529       have_pending_hard_failure_(false),
530       have_pending_runtime_throw_failure_(false),
531       have_pending_experimental_failure_(false),
532       have_any_pending_runtime_throw_failure_(false),
533       new_instance_count_(0),
534       monitor_enter_count_(0),
535       encountered_failure_types_(0),
536       can_load_classes_(can_load_classes),
537       allow_soft_failures_(allow_soft_failures),
538       need_precise_constants_(need_precise_constants),
539       has_check_casts_(false),
540       has_virtual_or_interface_invokes_(false),
541       verify_to_dump_(verify_to_dump),
542       allow_thread_suspension_(allow_thread_suspension),
543       is_constructor_(false),
544       link_(nullptr) {
545   self->PushVerifier(this);
546   DCHECK(class_def != nullptr);
547 }
548 
~MethodVerifier()549 MethodVerifier::~MethodVerifier() {
550   Thread::Current()->PopVerifier(this);
551   STLDeleteElements(&failure_messages_);
552 }
553 
FindLocksAtDexPc(ArtMethod * m,uint32_t dex_pc,std::vector<uint32_t> * monitor_enter_dex_pcs)554 void MethodVerifier::FindLocksAtDexPc(ArtMethod* m, uint32_t dex_pc,
555                                       std::vector<uint32_t>* monitor_enter_dex_pcs) {
556   StackHandleScope<2> hs(Thread::Current());
557   Handle<mirror::DexCache> dex_cache(hs.NewHandle(m->GetDexCache()));
558   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(m->GetClassLoader()));
559   MethodVerifier verifier(hs.Self(),
560                           m->GetDexFile(),
561                           dex_cache,
562                           class_loader,
563                           &m->GetClassDef(),
564                           m->GetCodeItem(),
565                           m->GetDexMethodIndex(),
566                           m,
567                           m->GetAccessFlags(),
568                           false /* can_load_classes */,
569                           true  /* allow_soft_failures */,
570                           false /* need_precise_constants */,
571                           false /* verify_to_dump */,
572                           false /* allow_thread_suspension */);
573   verifier.interesting_dex_pc_ = dex_pc;
574   verifier.monitor_enter_dex_pcs_ = monitor_enter_dex_pcs;
575   verifier.FindLocksAtDexPc();
576 }
577 
HasMonitorEnterInstructions(const DexFile::CodeItem * const code_item)578 static bool HasMonitorEnterInstructions(const DexFile::CodeItem* const code_item) {
579   const Instruction* inst = Instruction::At(code_item->insns_);
580 
581   uint32_t insns_size = code_item->insns_size_in_code_units_;
582   for (uint32_t dex_pc = 0; dex_pc < insns_size;) {
583     if (inst->Opcode() == Instruction::MONITOR_ENTER) {
584       return true;
585     }
586 
587     dex_pc += inst->SizeInCodeUnits();
588     inst = inst->Next();
589   }
590 
591   return false;
592 }
593 
FindLocksAtDexPc()594 void MethodVerifier::FindLocksAtDexPc() {
595   CHECK(monitor_enter_dex_pcs_ != nullptr);
596   CHECK(code_item_ != nullptr);  // This only makes sense for methods with code.
597 
598   // Quick check whether there are any monitor_enter instructions at all.
599   if (!HasMonitorEnterInstructions(code_item_)) {
600     return;
601   }
602 
603   // Strictly speaking, we ought to be able to get away with doing a subset of the full method
604   // verification. In practice, the phase we want relies on data structures set up by all the
605   // earlier passes, so we just run the full method verification and bail out early when we've
606   // got what we wanted.
607   Verify();
608 }
609 
FindAccessedFieldAtDexPc(ArtMethod * m,uint32_t dex_pc)610 ArtField* MethodVerifier::FindAccessedFieldAtDexPc(ArtMethod* m, uint32_t dex_pc) {
611   StackHandleScope<2> hs(Thread::Current());
612   Handle<mirror::DexCache> dex_cache(hs.NewHandle(m->GetDexCache()));
613   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(m->GetClassLoader()));
614   MethodVerifier verifier(hs.Self(),
615                           m->GetDexFile(),
616                           dex_cache,
617                           class_loader,
618                           &m->GetClassDef(),
619                           m->GetCodeItem(),
620                           m->GetDexMethodIndex(),
621                           m,
622                           m->GetAccessFlags(),
623                           true  /* can_load_classes */,
624                           true  /* allow_soft_failures */,
625                           false /* need_precise_constants */,
626                           false /* verify_to_dump */,
627                           true  /* allow_thread_suspension */);
628   return verifier.FindAccessedFieldAtDexPc(dex_pc);
629 }
630 
FindAccessedFieldAtDexPc(uint32_t dex_pc)631 ArtField* MethodVerifier::FindAccessedFieldAtDexPc(uint32_t dex_pc) {
632   CHECK(code_item_ != nullptr);  // This only makes sense for methods with code.
633 
634   // Strictly speaking, we ought to be able to get away with doing a subset of the full method
635   // verification. In practice, the phase we want relies on data structures set up by all the
636   // earlier passes, so we just run the full method verification and bail out early when we've
637   // got what we wanted.
638   bool success = Verify();
639   if (!success) {
640     return nullptr;
641   }
642   RegisterLine* register_line = reg_table_.GetLine(dex_pc);
643   if (register_line == nullptr) {
644     return nullptr;
645   }
646   const Instruction* inst = Instruction::At(code_item_->insns_ + dex_pc);
647   return GetQuickFieldAccess(inst, register_line);
648 }
649 
FindInvokedMethodAtDexPc(ArtMethod * m,uint32_t dex_pc)650 ArtMethod* MethodVerifier::FindInvokedMethodAtDexPc(ArtMethod* m, uint32_t dex_pc) {
651   StackHandleScope<2> hs(Thread::Current());
652   Handle<mirror::DexCache> dex_cache(hs.NewHandle(m->GetDexCache()));
653   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(m->GetClassLoader()));
654   MethodVerifier verifier(hs.Self(),
655                           m->GetDexFile(),
656                           dex_cache,
657                           class_loader,
658                           &m->GetClassDef(),
659                           m->GetCodeItem(),
660                           m->GetDexMethodIndex(),
661                           m,
662                           m->GetAccessFlags(),
663                           true  /* can_load_classes */,
664                           true  /* allow_soft_failures */,
665                           false /* need_precise_constants */,
666                           false /* verify_to_dump */,
667                           true  /* allow_thread_suspension */);
668   return verifier.FindInvokedMethodAtDexPc(dex_pc);
669 }
670 
FindInvokedMethodAtDexPc(uint32_t dex_pc)671 ArtMethod* MethodVerifier::FindInvokedMethodAtDexPc(uint32_t dex_pc) {
672   CHECK(code_item_ != nullptr);  // This only makes sense for methods with code.
673 
674   // Strictly speaking, we ought to be able to get away with doing a subset of the full method
675   // verification. In practice, the phase we want relies on data structures set up by all the
676   // earlier passes, so we just run the full method verification and bail out early when we've
677   // got what we wanted.
678   bool success = Verify();
679   if (!success) {
680     return nullptr;
681   }
682   RegisterLine* register_line = reg_table_.GetLine(dex_pc);
683   if (register_line == nullptr) {
684     return nullptr;
685   }
686   const Instruction* inst = Instruction::At(code_item_->insns_ + dex_pc);
687   const bool is_range = (inst->Opcode() == Instruction::INVOKE_VIRTUAL_RANGE_QUICK);
688   return GetQuickInvokedMethod(inst, register_line, is_range, false);
689 }
690 
Verify()691 bool MethodVerifier::Verify() {
692   // Some older code doesn't correctly mark constructors as such. Test for this case by looking at
693   // the name.
694   const DexFile::MethodId& method_id = dex_file_->GetMethodId(dex_method_idx_);
695   const char* method_name = dex_file_->StringDataByIdx(method_id.name_idx_);
696   bool instance_constructor_by_name = strcmp("<init>", method_name) == 0;
697   bool static_constructor_by_name = strcmp("<clinit>", method_name) == 0;
698   bool constructor_by_name = instance_constructor_by_name || static_constructor_by_name;
699   // Check that only constructors are tagged, and check for bad code that doesn't tag constructors.
700   if ((method_access_flags_ & kAccConstructor) != 0) {
701     if (!constructor_by_name) {
702       Fail(VERIFY_ERROR_BAD_CLASS_HARD)
703             << "method is marked as constructor, but not named accordingly";
704       return false;
705     }
706     is_constructor_ = true;
707   } else if (constructor_by_name) {
708     LOG(WARNING) << "Method " << PrettyMethod(dex_method_idx_, *dex_file_)
709                  << " not marked as constructor.";
710     is_constructor_ = true;
711   }
712   // If it's a constructor, check whether IsStatic() matches the name.
713   // This should have been rejected by the dex file verifier. Only do in debug build.
714   if (kIsDebugBuild) {
715     if (IsConstructor()) {
716       if (IsStatic() ^ static_constructor_by_name) {
717         Fail(VERIFY_ERROR_BAD_CLASS_HARD)
718               << "constructor name doesn't match static flag";
719         return false;
720       }
721     }
722   }
723 
724   // Methods may only have one of public/protected/private.
725   // This should have been rejected by the dex file verifier. Only do in debug build.
726   if (kIsDebugBuild) {
727     size_t access_mod_count =
728         (((method_access_flags_ & kAccPublic) == 0) ? 0 : 1) +
729         (((method_access_flags_ & kAccProtected) == 0) ? 0 : 1) +
730         (((method_access_flags_ & kAccPrivate) == 0) ? 0 : 1);
731     if (access_mod_count > 1) {
732       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "method has more than one of public/protected/private";
733       return false;
734     }
735   }
736 
737   // If there aren't any instructions, make sure that's expected, then exit successfully.
738   if (code_item_ == nullptr) {
739     // Only native or abstract methods may not have code.
740     if ((method_access_flags_ & (kAccNative | kAccAbstract)) == 0) {
741       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "zero-length code in concrete non-native method";
742       return false;
743     }
744 
745     // This should have been rejected by the dex file verifier. Only do in debug build.
746     // Note: the above will also be rejected in the dex file verifier, starting in dex version 37.
747     if (kIsDebugBuild) {
748       if ((method_access_flags_ & kAccAbstract) != 0) {
749         // Abstract methods are not allowed to have the following flags.
750         static constexpr uint32_t kForbidden =
751             kAccPrivate |
752             kAccStatic |
753             kAccFinal |
754             kAccNative |
755             kAccStrict |
756             kAccSynchronized;
757         if ((method_access_flags_ & kForbidden) != 0) {
758           Fail(VERIFY_ERROR_BAD_CLASS_HARD)
759                 << "method can't be abstract and private/static/final/native/strict/synchronized";
760           return false;
761         }
762       }
763       if ((class_def_->GetJavaAccessFlags() & kAccInterface) != 0) {
764         // Interface methods must be public and abstract (if default methods are disabled).
765         uint32_t kRequired = kAccPublic;
766         if ((method_access_flags_ & kRequired) != kRequired) {
767           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "interface methods must be public";
768           return false;
769         }
770         // In addition to the above, interface methods must not be protected.
771         static constexpr uint32_t kForbidden = kAccProtected;
772         if ((method_access_flags_ & kForbidden) != 0) {
773           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "interface methods can't be protected";
774           return false;
775         }
776       }
777       // We also don't allow constructors to be abstract or native.
778       if (IsConstructor()) {
779         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "constructors can't be abstract or native";
780         return false;
781       }
782     }
783     return true;
784   }
785 
786   // This should have been rejected by the dex file verifier. Only do in debug build.
787   if (kIsDebugBuild) {
788     // When there's code, the method must not be native or abstract.
789     if ((method_access_flags_ & (kAccNative | kAccAbstract)) != 0) {
790       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "non-zero-length code in abstract or native method";
791       return false;
792     }
793 
794     if ((class_def_->GetJavaAccessFlags() & kAccInterface) != 0) {
795       // Interfaces may always have static initializers for their fields. If we are running with
796       // default methods enabled we also allow other public, static, non-final methods to have code.
797       // Otherwise that is the only type of method allowed.
798       if (!(IsConstructor() && IsStatic())) {
799         if (IsInstanceConstructor()) {
800           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "interfaces may not have non-static constructor";
801           return false;
802         } else if (method_access_flags_ & kAccFinal) {
803           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "interfaces may not have final methods";
804           return false;
805         } else {
806           uint32_t access_flag_options = kAccPublic;
807           if (dex_file_->GetVersion() >= DexFile::kDefaultMethodsVersion) {
808             access_flag_options |= kAccPrivate;
809           }
810           if (!(method_access_flags_ & access_flag_options)) {
811             Fail(VERIFY_ERROR_BAD_CLASS_HARD)
812                 << "interfaces may not have protected or package-private members";
813             return false;
814           }
815         }
816       }
817     }
818 
819     // Instance constructors must not be synchronized.
820     if (IsInstanceConstructor()) {
821       static constexpr uint32_t kForbidden = kAccSynchronized;
822       if ((method_access_flags_ & kForbidden) != 0) {
823         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "constructors can't be synchronized";
824         return false;
825       }
826     }
827   }
828 
829   // Sanity-check the register counts. ins + locals = registers, so make sure that ins <= registers.
830   if (code_item_->ins_size_ > code_item_->registers_size_) {
831     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad register counts (ins=" << code_item_->ins_size_
832                                       << " regs=" << code_item_->registers_size_;
833     return false;
834   }
835 
836   // Allocate and initialize an array to hold instruction data.
837   insn_flags_.reset(arena_.AllocArray<InstructionFlags>(code_item_->insns_size_in_code_units_));
838   DCHECK(insn_flags_ != nullptr);
839   std::uninitialized_fill_n(insn_flags_.get(),
840                             code_item_->insns_size_in_code_units_,
841                             InstructionFlags());
842   // Run through the instructions and see if the width checks out.
843   bool result = ComputeWidthsAndCountOps();
844   // Flag instructions guarded by a "try" block and check exception handlers.
845   result = result && ScanTryCatchBlocks();
846   // Perform static instruction verification.
847   result = result && VerifyInstructions();
848   // Perform code-flow analysis and return.
849   result = result && VerifyCodeFlow();
850 
851   return result;
852 }
853 
Fail(VerifyError error)854 std::ostream& MethodVerifier::Fail(VerifyError error) {
855   // Mark the error type as encountered.
856   encountered_failure_types_ |= static_cast<uint32_t>(error);
857 
858   switch (error) {
859     case VERIFY_ERROR_NO_CLASS:
860     case VERIFY_ERROR_NO_FIELD:
861     case VERIFY_ERROR_NO_METHOD:
862     case VERIFY_ERROR_ACCESS_CLASS:
863     case VERIFY_ERROR_ACCESS_FIELD:
864     case VERIFY_ERROR_ACCESS_METHOD:
865     case VERIFY_ERROR_INSTANTIATION:
866     case VERIFY_ERROR_CLASS_CHANGE:
867     case VERIFY_ERROR_FORCE_INTERPRETER:
868     case VERIFY_ERROR_LOCKING:
869       if (Runtime::Current()->IsAotCompiler() || !can_load_classes_) {
870         // If we're optimistically running verification at compile time, turn NO_xxx, ACCESS_xxx,
871         // class change and instantiation errors into soft verification errors so that we re-verify
872         // at runtime. We may fail to find or to agree on access because of not yet available class
873         // loaders, or class loaders that will differ at runtime. In these cases, we don't want to
874         // affect the soundness of the code being compiled. Instead, the generated code runs "slow
875         // paths" that dynamically perform the verification and cause the behavior to be that akin
876         // to an interpreter.
877         error = VERIFY_ERROR_BAD_CLASS_SOFT;
878       } else {
879         // If we fail again at runtime, mark that this instruction would throw and force this
880         // method to be executed using the interpreter with checks.
881         have_pending_runtime_throw_failure_ = true;
882 
883         // We need to save the work_line if the instruction wasn't throwing before. Otherwise we'll
884         // try to merge garbage.
885         // Note: this assumes that Fail is called before we do any work_line modifications.
886         // Note: this can fail before we touch any instruction, for the signature of a method. So
887         //       add a check.
888         if (work_insn_idx_ < DexFile::kDexNoIndex) {
889           const uint16_t* insns = code_item_->insns_ + work_insn_idx_;
890           const Instruction* inst = Instruction::At(insns);
891           int opcode_flags = Instruction::FlagsOf(inst->Opcode());
892 
893           if ((opcode_flags & Instruction::kThrow) == 0 && CurrentInsnFlags()->IsInTry()) {
894             saved_line_->CopyFromLine(work_line_.get());
895           }
896         }
897       }
898       break;
899 
900       // Indication that verification should be retried at runtime.
901     case VERIFY_ERROR_BAD_CLASS_SOFT:
902       if (!allow_soft_failures_) {
903         have_pending_hard_failure_ = true;
904       }
905       break;
906 
907       // Hard verification failures at compile time will still fail at runtime, so the class is
908       // marked as rejected to prevent it from being compiled.
909     case VERIFY_ERROR_BAD_CLASS_HARD: {
910       have_pending_hard_failure_ = true;
911       if (VLOG_IS_ON(verifier) && kDumpRegLinesOnHardFailureIfVLOG) {
912         ScopedObjectAccess soa(Thread::Current());
913         std::ostringstream oss;
914         Dump(oss);
915         LOG(ERROR) << oss.str();
916       }
917       break;
918     }
919   }
920   failures_.push_back(error);
921   std::string location(StringPrintf("%s: [0x%X] ", PrettyMethod(dex_method_idx_, *dex_file_).c_str(),
922                                     work_insn_idx_));
923   std::ostringstream* failure_message = new std::ostringstream(location, std::ostringstream::ate);
924   failure_messages_.push_back(failure_message);
925   return *failure_message;
926 }
927 
LogVerifyInfo()928 std::ostream& MethodVerifier::LogVerifyInfo() {
929   return info_messages_ << "VFY: " << PrettyMethod(dex_method_idx_, *dex_file_)
930                         << '[' << reinterpret_cast<void*>(work_insn_idx_) << "] : ";
931 }
932 
PrependToLastFailMessage(std::string prepend)933 void MethodVerifier::PrependToLastFailMessage(std::string prepend) {
934   size_t failure_num = failure_messages_.size();
935   DCHECK_NE(failure_num, 0U);
936   std::ostringstream* last_fail_message = failure_messages_[failure_num - 1];
937   prepend += last_fail_message->str();
938   failure_messages_[failure_num - 1] = new std::ostringstream(prepend, std::ostringstream::ate);
939   delete last_fail_message;
940 }
941 
AppendToLastFailMessage(std::string append)942 void MethodVerifier::AppendToLastFailMessage(std::string append) {
943   size_t failure_num = failure_messages_.size();
944   DCHECK_NE(failure_num, 0U);
945   std::ostringstream* last_fail_message = failure_messages_[failure_num - 1];
946   (*last_fail_message) << append;
947 }
948 
ComputeWidthsAndCountOps()949 bool MethodVerifier::ComputeWidthsAndCountOps() {
950   const uint16_t* insns = code_item_->insns_;
951   size_t insns_size = code_item_->insns_size_in_code_units_;
952   const Instruction* inst = Instruction::At(insns);
953   size_t new_instance_count = 0;
954   size_t monitor_enter_count = 0;
955   size_t dex_pc = 0;
956 
957   while (dex_pc < insns_size) {
958     Instruction::Code opcode = inst->Opcode();
959     switch (opcode) {
960       case Instruction::APUT_OBJECT:
961       case Instruction::CHECK_CAST:
962         has_check_casts_ = true;
963         break;
964       case Instruction::INVOKE_VIRTUAL:
965       case Instruction::INVOKE_VIRTUAL_RANGE:
966       case Instruction::INVOKE_INTERFACE:
967       case Instruction::INVOKE_INTERFACE_RANGE:
968         has_virtual_or_interface_invokes_ = true;
969         break;
970       case Instruction::MONITOR_ENTER:
971         monitor_enter_count++;
972         break;
973       case Instruction::NEW_INSTANCE:
974         new_instance_count++;
975         break;
976       default:
977         break;
978     }
979     size_t inst_size = inst->SizeInCodeUnits();
980     GetInstructionFlags(dex_pc).SetIsOpcode();
981     dex_pc += inst_size;
982     inst = inst->RelativeAt(inst_size);
983   }
984 
985   if (dex_pc != insns_size) {
986     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "code did not end where expected ("
987                                       << dex_pc << " vs. " << insns_size << ")";
988     return false;
989   }
990 
991   new_instance_count_ = new_instance_count;
992   monitor_enter_count_ = monitor_enter_count;
993   return true;
994 }
995 
ScanTryCatchBlocks()996 bool MethodVerifier::ScanTryCatchBlocks() {
997   uint32_t tries_size = code_item_->tries_size_;
998   if (tries_size == 0) {
999     return true;
1000   }
1001   uint32_t insns_size = code_item_->insns_size_in_code_units_;
1002   const DexFile::TryItem* tries = DexFile::GetTryItems(*code_item_, 0);
1003 
1004   for (uint32_t idx = 0; idx < tries_size; idx++) {
1005     const DexFile::TryItem* try_item = &tries[idx];
1006     uint32_t start = try_item->start_addr_;
1007     uint32_t end = start + try_item->insn_count_;
1008     if ((start >= end) || (start >= insns_size) || (end > insns_size)) {
1009       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad exception entry: startAddr=" << start
1010                                         << " endAddr=" << end << " (size=" << insns_size << ")";
1011       return false;
1012     }
1013     if (!GetInstructionFlags(start).IsOpcode()) {
1014       Fail(VERIFY_ERROR_BAD_CLASS_HARD)
1015           << "'try' block starts inside an instruction (" << start << ")";
1016       return false;
1017     }
1018     uint32_t dex_pc = start;
1019     const Instruction* inst = Instruction::At(code_item_->insns_ + dex_pc);
1020     while (dex_pc < end) {
1021       GetInstructionFlags(dex_pc).SetInTry();
1022       size_t insn_size = inst->SizeInCodeUnits();
1023       dex_pc += insn_size;
1024       inst = inst->RelativeAt(insn_size);
1025     }
1026   }
1027   // Iterate over each of the handlers to verify target addresses.
1028   const uint8_t* handlers_ptr = DexFile::GetCatchHandlerData(*code_item_, 0);
1029   uint32_t handlers_size = DecodeUnsignedLeb128(&handlers_ptr);
1030   ClassLinker* linker = Runtime::Current()->GetClassLinker();
1031   for (uint32_t idx = 0; idx < handlers_size; idx++) {
1032     CatchHandlerIterator iterator(handlers_ptr);
1033     for (; iterator.HasNext(); iterator.Next()) {
1034       uint32_t dex_pc= iterator.GetHandlerAddress();
1035       if (!GetInstructionFlags(dex_pc).IsOpcode()) {
1036         Fail(VERIFY_ERROR_BAD_CLASS_HARD)
1037             << "exception handler starts at bad address (" << dex_pc << ")";
1038         return false;
1039       }
1040       if (!CheckNotMoveResult(code_item_->insns_, dex_pc)) {
1041         Fail(VERIFY_ERROR_BAD_CLASS_HARD)
1042             << "exception handler begins with move-result* (" << dex_pc << ")";
1043         return false;
1044       }
1045       GetInstructionFlags(dex_pc).SetBranchTarget();
1046       // Ensure exception types are resolved so that they don't need resolution to be delivered,
1047       // unresolved exception types will be ignored by exception delivery
1048       if (iterator.GetHandlerTypeIndex() != DexFile::kDexNoIndex16) {
1049         mirror::Class* exception_type = linker->ResolveType(*dex_file_,
1050                                                             iterator.GetHandlerTypeIndex(),
1051                                                             dex_cache_, class_loader_);
1052         if (exception_type == nullptr) {
1053           DCHECK(self_->IsExceptionPending());
1054           self_->ClearException();
1055         }
1056       }
1057     }
1058     handlers_ptr = iterator.EndDataPointer();
1059   }
1060   return true;
1061 }
1062 
VerifyInstructions()1063 bool MethodVerifier::VerifyInstructions() {
1064   const Instruction* inst = Instruction::At(code_item_->insns_);
1065 
1066   /* Flag the start of the method as a branch target, and a GC point due to stack overflow errors */
1067   GetInstructionFlags(0).SetBranchTarget();
1068   GetInstructionFlags(0).SetCompileTimeInfoPoint();
1069 
1070   uint32_t insns_size = code_item_->insns_size_in_code_units_;
1071   for (uint32_t dex_pc = 0; dex_pc < insns_size;) {
1072     if (!VerifyInstruction(inst, dex_pc)) {
1073       DCHECK_NE(failures_.size(), 0U);
1074       return false;
1075     }
1076     /* Flag instructions that are garbage collection points */
1077     // All invoke points are marked as "Throw" points already.
1078     // We are relying on this to also count all the invokes as interesting.
1079     if (inst->IsBranch()) {
1080       GetInstructionFlags(dex_pc).SetCompileTimeInfoPoint();
1081       // The compiler also needs safepoints for fall-through to loop heads.
1082       // Such a loop head must be a target of a branch.
1083       int32_t offset = 0;
1084       bool cond, self_ok;
1085       bool target_ok = GetBranchOffset(dex_pc, &offset, &cond, &self_ok);
1086       DCHECK(target_ok);
1087       GetInstructionFlags(dex_pc + offset).SetCompileTimeInfoPoint();
1088     } else if (inst->IsSwitch() || inst->IsThrow()) {
1089       GetInstructionFlags(dex_pc).SetCompileTimeInfoPoint();
1090     } else if (inst->IsReturn()) {
1091       GetInstructionFlags(dex_pc).SetCompileTimeInfoPointAndReturn();
1092     }
1093     dex_pc += inst->SizeInCodeUnits();
1094     inst = inst->Next();
1095   }
1096   return true;
1097 }
1098 
VerifyInstruction(const Instruction * inst,uint32_t code_offset)1099 bool MethodVerifier::VerifyInstruction(const Instruction* inst, uint32_t code_offset) {
1100   if (UNLIKELY(inst->IsExperimental())) {
1101     // Experimental instructions don't yet have verifier support implementation.
1102     // While it is possible to use them by themselves, when we try to use stable instructions
1103     // with a virtual register that was created by an experimental instruction,
1104     // the data flow analysis will fail.
1105     Fail(VERIFY_ERROR_FORCE_INTERPRETER)
1106         << "experimental instruction is not supported by verifier; skipping verification";
1107     have_pending_experimental_failure_ = true;
1108     return false;
1109   }
1110 
1111   bool result = true;
1112   switch (inst->GetVerifyTypeArgumentA()) {
1113     case Instruction::kVerifyRegA:
1114       result = result && CheckRegisterIndex(inst->VRegA());
1115       break;
1116     case Instruction::kVerifyRegAWide:
1117       result = result && CheckWideRegisterIndex(inst->VRegA());
1118       break;
1119   }
1120   switch (inst->GetVerifyTypeArgumentB()) {
1121     case Instruction::kVerifyRegB:
1122       result = result && CheckRegisterIndex(inst->VRegB());
1123       break;
1124     case Instruction::kVerifyRegBField:
1125       result = result && CheckFieldIndex(inst->VRegB());
1126       break;
1127     case Instruction::kVerifyRegBMethod:
1128       result = result && CheckMethodIndex(inst->VRegB());
1129       break;
1130     case Instruction::kVerifyRegBNewInstance:
1131       result = result && CheckNewInstance(inst->VRegB());
1132       break;
1133     case Instruction::kVerifyRegBString:
1134       result = result && CheckStringIndex(inst->VRegB());
1135       break;
1136     case Instruction::kVerifyRegBType:
1137       result = result && CheckTypeIndex(inst->VRegB());
1138       break;
1139     case Instruction::kVerifyRegBWide:
1140       result = result && CheckWideRegisterIndex(inst->VRegB());
1141       break;
1142   }
1143   switch (inst->GetVerifyTypeArgumentC()) {
1144     case Instruction::kVerifyRegC:
1145       result = result && CheckRegisterIndex(inst->VRegC());
1146       break;
1147     case Instruction::kVerifyRegCField:
1148       result = result && CheckFieldIndex(inst->VRegC());
1149       break;
1150     case Instruction::kVerifyRegCNewArray:
1151       result = result && CheckNewArray(inst->VRegC());
1152       break;
1153     case Instruction::kVerifyRegCType:
1154       result = result && CheckTypeIndex(inst->VRegC());
1155       break;
1156     case Instruction::kVerifyRegCWide:
1157       result = result && CheckWideRegisterIndex(inst->VRegC());
1158       break;
1159     case Instruction::kVerifyRegCString:
1160       result = result && CheckStringIndex(inst->VRegC());
1161       break;
1162   }
1163   switch (inst->GetVerifyExtraFlags()) {
1164     case Instruction::kVerifyArrayData:
1165       result = result && CheckArrayData(code_offset);
1166       break;
1167     case Instruction::kVerifyBranchTarget:
1168       result = result && CheckBranchTarget(code_offset);
1169       break;
1170     case Instruction::kVerifySwitchTargets:
1171       result = result && CheckSwitchTargets(code_offset);
1172       break;
1173     case Instruction::kVerifyVarArgNonZero:
1174       // Fall-through.
1175     case Instruction::kVerifyVarArg: {
1176       // Instructions that can actually return a negative value shouldn't have this flag.
1177       uint32_t v_a = dchecked_integral_cast<uint32_t>(inst->VRegA());
1178       if ((inst->GetVerifyExtraFlags() == Instruction::kVerifyVarArgNonZero && v_a == 0) ||
1179           v_a > Instruction::kMaxVarArgRegs) {
1180         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid arg count (" << v_a << ") in "
1181                                              "non-range invoke";
1182         return false;
1183       }
1184 
1185       uint32_t args[Instruction::kMaxVarArgRegs];
1186       inst->GetVarArgs(args);
1187       result = result && CheckVarArgRegs(v_a, args);
1188       break;
1189     }
1190     case Instruction::kVerifyVarArgRangeNonZero:
1191       // Fall-through.
1192     case Instruction::kVerifyVarArgRange:
1193       if (inst->GetVerifyExtraFlags() == Instruction::kVerifyVarArgRangeNonZero &&
1194           inst->VRegA() <= 0) {
1195         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid arg count (" << inst->VRegA() << ") in "
1196                                              "range invoke";
1197         return false;
1198       }
1199       result = result && CheckVarArgRangeRegs(inst->VRegA(), inst->VRegC());
1200       break;
1201     case Instruction::kVerifyError:
1202       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unexpected opcode " << inst->Name();
1203       result = false;
1204       break;
1205   }
1206   if (inst->GetVerifyIsRuntimeOnly() && Runtime::Current()->IsAotCompiler() && !verify_to_dump_) {
1207     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "opcode only expected at runtime " << inst->Name();
1208     result = false;
1209   }
1210   return result;
1211 }
1212 
CheckRegisterIndex(uint32_t idx)1213 inline bool MethodVerifier::CheckRegisterIndex(uint32_t idx) {
1214   if (idx >= code_item_->registers_size_) {
1215     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "register index out of range (" << idx << " >= "
1216                                       << code_item_->registers_size_ << ")";
1217     return false;
1218   }
1219   return true;
1220 }
1221 
CheckWideRegisterIndex(uint32_t idx)1222 inline bool MethodVerifier::CheckWideRegisterIndex(uint32_t idx) {
1223   if (idx + 1 >= code_item_->registers_size_) {
1224     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "wide register index out of range (" << idx
1225                                       << "+1 >= " << code_item_->registers_size_ << ")";
1226     return false;
1227   }
1228   return true;
1229 }
1230 
CheckFieldIndex(uint32_t idx)1231 inline bool MethodVerifier::CheckFieldIndex(uint32_t idx) {
1232   if (idx >= dex_file_->GetHeader().field_ids_size_) {
1233     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad field index " << idx << " (max "
1234                                       << dex_file_->GetHeader().field_ids_size_ << ")";
1235     return false;
1236   }
1237   return true;
1238 }
1239 
CheckMethodIndex(uint32_t idx)1240 inline bool MethodVerifier::CheckMethodIndex(uint32_t idx) {
1241   if (idx >= dex_file_->GetHeader().method_ids_size_) {
1242     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad method index " << idx << " (max "
1243                                       << dex_file_->GetHeader().method_ids_size_ << ")";
1244     return false;
1245   }
1246   return true;
1247 }
1248 
CheckNewInstance(uint32_t idx)1249 inline bool MethodVerifier::CheckNewInstance(uint32_t idx) {
1250   if (idx >= dex_file_->GetHeader().type_ids_size_) {
1251     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad type index " << idx << " (max "
1252                                       << dex_file_->GetHeader().type_ids_size_ << ")";
1253     return false;
1254   }
1255   // We don't need the actual class, just a pointer to the class name.
1256   const char* descriptor = dex_file_->StringByTypeIdx(idx);
1257   if (descriptor[0] != 'L') {
1258     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "can't call new-instance on type '" << descriptor << "'";
1259     return false;
1260   }
1261   return true;
1262 }
1263 
CheckStringIndex(uint32_t idx)1264 inline bool MethodVerifier::CheckStringIndex(uint32_t idx) {
1265   if (idx >= dex_file_->GetHeader().string_ids_size_) {
1266     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad string index " << idx << " (max "
1267                                       << dex_file_->GetHeader().string_ids_size_ << ")";
1268     return false;
1269   }
1270   return true;
1271 }
1272 
CheckTypeIndex(uint32_t idx)1273 inline bool MethodVerifier::CheckTypeIndex(uint32_t idx) {
1274   if (idx >= dex_file_->GetHeader().type_ids_size_) {
1275     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad type index " << idx << " (max "
1276                                       << dex_file_->GetHeader().type_ids_size_ << ")";
1277     return false;
1278   }
1279   return true;
1280 }
1281 
CheckNewArray(uint32_t idx)1282 bool MethodVerifier::CheckNewArray(uint32_t idx) {
1283   if (idx >= dex_file_->GetHeader().type_ids_size_) {
1284     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad type index " << idx << " (max "
1285                                       << dex_file_->GetHeader().type_ids_size_ << ")";
1286     return false;
1287   }
1288   int bracket_count = 0;
1289   const char* descriptor = dex_file_->StringByTypeIdx(idx);
1290   const char* cp = descriptor;
1291   while (*cp++ == '[') {
1292     bracket_count++;
1293   }
1294   if (bracket_count == 0) {
1295     /* The given class must be an array type. */
1296     Fail(VERIFY_ERROR_BAD_CLASS_HARD)
1297         << "can't new-array class '" << descriptor << "' (not an array)";
1298     return false;
1299   } else if (bracket_count > 255) {
1300     /* It is illegal to create an array of more than 255 dimensions. */
1301     Fail(VERIFY_ERROR_BAD_CLASS_HARD)
1302         << "can't new-array class '" << descriptor << "' (exceeds limit)";
1303     return false;
1304   }
1305   return true;
1306 }
1307 
CheckArrayData(uint32_t cur_offset)1308 bool MethodVerifier::CheckArrayData(uint32_t cur_offset) {
1309   const uint32_t insn_count = code_item_->insns_size_in_code_units_;
1310   const uint16_t* insns = code_item_->insns_ + cur_offset;
1311   const uint16_t* array_data;
1312   int32_t array_data_offset;
1313 
1314   DCHECK_LT(cur_offset, insn_count);
1315   /* make sure the start of the array data table is in range */
1316   array_data_offset = insns[1] | (static_cast<int32_t>(insns[2]) << 16);
1317   if (static_cast<int32_t>(cur_offset) + array_data_offset < 0 ||
1318       cur_offset + array_data_offset + 2 >= insn_count) {
1319     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid array data start: at " << cur_offset
1320                                       << ", data offset " << array_data_offset
1321                                       << ", count " << insn_count;
1322     return false;
1323   }
1324   /* offset to array data table is a relative branch-style offset */
1325   array_data = insns + array_data_offset;
1326   // Make sure the table is at an even dex pc, that is, 32-bit aligned.
1327   if (!IsAligned<4>(array_data)) {
1328     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unaligned array data table: at " << cur_offset
1329                                       << ", data offset " << array_data_offset;
1330     return false;
1331   }
1332   // Make sure the array-data is marked as an opcode. This ensures that it was reached when
1333   // traversing the code item linearly. It is an approximation for a by-spec padding value.
1334   if (!GetInstructionFlags(cur_offset + array_data_offset).IsOpcode()) {
1335     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "array data table at " << cur_offset
1336                                       << ", data offset " << array_data_offset
1337                                       << " not correctly visited, probably bad padding.";
1338     return false;
1339   }
1340 
1341   uint32_t value_width = array_data[1];
1342   uint32_t value_count = *reinterpret_cast<const uint32_t*>(&array_data[2]);
1343   uint32_t table_size = 4 + (value_width * value_count + 1) / 2;
1344   /* make sure the end of the switch is in range */
1345   if (cur_offset + array_data_offset + table_size > insn_count) {
1346     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid array data end: at " << cur_offset
1347                                       << ", data offset " << array_data_offset << ", end "
1348                                       << cur_offset + array_data_offset + table_size
1349                                       << ", count " << insn_count;
1350     return false;
1351   }
1352   return true;
1353 }
1354 
CheckBranchTarget(uint32_t cur_offset)1355 bool MethodVerifier::CheckBranchTarget(uint32_t cur_offset) {
1356   int32_t offset;
1357   bool isConditional, selfOkay;
1358   if (!GetBranchOffset(cur_offset, &offset, &isConditional, &selfOkay)) {
1359     return false;
1360   }
1361   if (!selfOkay && offset == 0) {
1362     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "branch offset of zero not allowed at"
1363                                       << reinterpret_cast<void*>(cur_offset);
1364     return false;
1365   }
1366   // Check for 32-bit overflow. This isn't strictly necessary if we can depend on the runtime
1367   // to have identical "wrap-around" behavior, but it's unwise to depend on that.
1368   if (((int64_t) cur_offset + (int64_t) offset) != (int64_t) (cur_offset + offset)) {
1369     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "branch target overflow "
1370                                       << reinterpret_cast<void*>(cur_offset) << " +" << offset;
1371     return false;
1372   }
1373   const uint32_t insn_count = code_item_->insns_size_in_code_units_;
1374   int32_t abs_offset = cur_offset + offset;
1375   if (abs_offset < 0 ||
1376       (uint32_t) abs_offset >= insn_count ||
1377       !GetInstructionFlags(abs_offset).IsOpcode()) {
1378     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid branch target " << offset << " (-> "
1379                                       << reinterpret_cast<void*>(abs_offset) << ") at "
1380                                       << reinterpret_cast<void*>(cur_offset);
1381     return false;
1382   }
1383   GetInstructionFlags(abs_offset).SetBranchTarget();
1384   return true;
1385 }
1386 
GetBranchOffset(uint32_t cur_offset,int32_t * pOffset,bool * pConditional,bool * selfOkay)1387 bool MethodVerifier::GetBranchOffset(uint32_t cur_offset, int32_t* pOffset, bool* pConditional,
1388                                   bool* selfOkay) {
1389   const uint16_t* insns = code_item_->insns_ + cur_offset;
1390   *pConditional = false;
1391   *selfOkay = false;
1392   switch (*insns & 0xff) {
1393     case Instruction::GOTO:
1394       *pOffset = ((int16_t) *insns) >> 8;
1395       break;
1396     case Instruction::GOTO_32:
1397       *pOffset = insns[1] | (((uint32_t) insns[2]) << 16);
1398       *selfOkay = true;
1399       break;
1400     case Instruction::GOTO_16:
1401       *pOffset = (int16_t) insns[1];
1402       break;
1403     case Instruction::IF_EQ:
1404     case Instruction::IF_NE:
1405     case Instruction::IF_LT:
1406     case Instruction::IF_GE:
1407     case Instruction::IF_GT:
1408     case Instruction::IF_LE:
1409     case Instruction::IF_EQZ:
1410     case Instruction::IF_NEZ:
1411     case Instruction::IF_LTZ:
1412     case Instruction::IF_GEZ:
1413     case Instruction::IF_GTZ:
1414     case Instruction::IF_LEZ:
1415       *pOffset = (int16_t) insns[1];
1416       *pConditional = true;
1417       break;
1418     default:
1419       return false;
1420   }
1421   return true;
1422 }
1423 
CheckSwitchTargets(uint32_t cur_offset)1424 bool MethodVerifier::CheckSwitchTargets(uint32_t cur_offset) {
1425   const uint32_t insn_count = code_item_->insns_size_in_code_units_;
1426   DCHECK_LT(cur_offset, insn_count);
1427   const uint16_t* insns = code_item_->insns_ + cur_offset;
1428   /* make sure the start of the switch is in range */
1429   int32_t switch_offset = insns[1] | (static_cast<int32_t>(insns[2]) << 16);
1430   if (static_cast<int32_t>(cur_offset) + switch_offset < 0 ||
1431       cur_offset + switch_offset + 2 > insn_count) {
1432     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid switch start: at " << cur_offset
1433                                       << ", switch offset " << switch_offset
1434                                       << ", count " << insn_count;
1435     return false;
1436   }
1437   /* offset to switch table is a relative branch-style offset */
1438   const uint16_t* switch_insns = insns + switch_offset;
1439   // Make sure the table is at an even dex pc, that is, 32-bit aligned.
1440   if (!IsAligned<4>(switch_insns)) {
1441     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unaligned switch table: at " << cur_offset
1442                                       << ", switch offset " << switch_offset;
1443     return false;
1444   }
1445   // Make sure the switch data is marked as an opcode. This ensures that it was reached when
1446   // traversing the code item linearly. It is an approximation for a by-spec padding value.
1447   if (!GetInstructionFlags(cur_offset + switch_offset).IsOpcode()) {
1448     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "switch table at " << cur_offset
1449                                       << ", switch offset " << switch_offset
1450                                       << " not correctly visited, probably bad padding.";
1451     return false;
1452   }
1453 
1454   bool is_packed_switch = (*insns & 0xff) == Instruction::PACKED_SWITCH;
1455 
1456   uint32_t switch_count = switch_insns[1];
1457   int32_t targets_offset;
1458   uint16_t expected_signature;
1459   if (is_packed_switch) {
1460     /* 0=sig, 1=count, 2/3=firstKey */
1461     targets_offset = 4;
1462     expected_signature = Instruction::kPackedSwitchSignature;
1463   } else {
1464     /* 0=sig, 1=count, 2..count*2 = keys */
1465     targets_offset = 2 + 2 * switch_count;
1466     expected_signature = Instruction::kSparseSwitchSignature;
1467   }
1468   uint32_t table_size = targets_offset + switch_count * 2;
1469   if (switch_insns[0] != expected_signature) {
1470     Fail(VERIFY_ERROR_BAD_CLASS_HARD)
1471         << StringPrintf("wrong signature for switch table (%x, wanted %x)",
1472                         switch_insns[0], expected_signature);
1473     return false;
1474   }
1475   /* make sure the end of the switch is in range */
1476   if (cur_offset + switch_offset + table_size > (uint32_t) insn_count) {
1477     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid switch end: at " << cur_offset
1478                                       << ", switch offset " << switch_offset
1479                                       << ", end " << (cur_offset + switch_offset + table_size)
1480                                       << ", count " << insn_count;
1481     return false;
1482   }
1483 
1484   constexpr int32_t keys_offset = 2;
1485   if (switch_count > 1) {
1486     if (is_packed_switch) {
1487       /* for a packed switch, verify that keys do not overflow int32 */
1488       int32_t first_key = switch_insns[keys_offset] | (switch_insns[keys_offset + 1] << 16);
1489       int32_t max_first_key =
1490           std::numeric_limits<int32_t>::max() - (static_cast<int32_t>(switch_count) - 1);
1491       if (first_key > max_first_key) {
1492         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid packed switch: first_key=" << first_key
1493                                           << ", switch_count=" << switch_count;
1494         return false;
1495       }
1496     } else {
1497       /* for a sparse switch, verify the keys are in ascending order */
1498       int32_t last_key = switch_insns[keys_offset] | (switch_insns[keys_offset + 1] << 16);
1499       for (uint32_t targ = 1; targ < switch_count; targ++) {
1500         int32_t key =
1501             static_cast<int32_t>(switch_insns[keys_offset + targ * 2]) |
1502             static_cast<int32_t>(switch_insns[keys_offset + targ * 2 + 1] << 16);
1503         if (key <= last_key) {
1504           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid sparse switch: last key=" << last_key
1505                                             << ", this=" << key;
1506           return false;
1507         }
1508         last_key = key;
1509       }
1510     }
1511   }
1512   /* verify each switch target */
1513   for (uint32_t targ = 0; targ < switch_count; targ++) {
1514     int32_t offset = static_cast<int32_t>(switch_insns[targets_offset + targ * 2]) |
1515                      static_cast<int32_t>(switch_insns[targets_offset + targ * 2 + 1] << 16);
1516     int32_t abs_offset = cur_offset + offset;
1517     if (abs_offset < 0 ||
1518         abs_offset >= static_cast<int32_t>(insn_count) ||
1519         !GetInstructionFlags(abs_offset).IsOpcode()) {
1520       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid switch target " << offset
1521                                         << " (-> " << reinterpret_cast<void*>(abs_offset) << ") at "
1522                                         << reinterpret_cast<void*>(cur_offset)
1523                                         << "[" << targ << "]";
1524       return false;
1525     }
1526     GetInstructionFlags(abs_offset).SetBranchTarget();
1527   }
1528   return true;
1529 }
1530 
CheckVarArgRegs(uint32_t vA,uint32_t arg[])1531 bool MethodVerifier::CheckVarArgRegs(uint32_t vA, uint32_t arg[]) {
1532   uint16_t registers_size = code_item_->registers_size_;
1533   for (uint32_t idx = 0; idx < vA; idx++) {
1534     if (arg[idx] >= registers_size) {
1535       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid reg index (" << arg[idx]
1536                                         << ") in non-range invoke (>= " << registers_size << ")";
1537       return false;
1538     }
1539   }
1540 
1541   return true;
1542 }
1543 
CheckVarArgRangeRegs(uint32_t vA,uint32_t vC)1544 bool MethodVerifier::CheckVarArgRangeRegs(uint32_t vA, uint32_t vC) {
1545   uint16_t registers_size = code_item_->registers_size_;
1546   // vA/vC are unsigned 8-bit/16-bit quantities for /range instructions, so there's no risk of
1547   // integer overflow when adding them here.
1548   if (vA + vC > registers_size) {
1549     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid reg index " << vA << "+" << vC
1550                                       << " in range invoke (> " << registers_size << ")";
1551     return false;
1552   }
1553   return true;
1554 }
1555 
VerifyCodeFlow()1556 bool MethodVerifier::VerifyCodeFlow() {
1557   uint16_t registers_size = code_item_->registers_size_;
1558   uint32_t insns_size = code_item_->insns_size_in_code_units_;
1559 
1560   /* Create and initialize table holding register status */
1561   reg_table_.Init(kTrackCompilerInterestPoints,
1562                   insn_flags_.get(),
1563                   insns_size,
1564                   registers_size,
1565                   this);
1566 
1567   work_line_.reset(RegisterLine::Create(registers_size, this));
1568   saved_line_.reset(RegisterLine::Create(registers_size, this));
1569 
1570   /* Initialize register types of method arguments. */
1571   if (!SetTypesFromSignature()) {
1572     DCHECK_NE(failures_.size(), 0U);
1573     std::string prepend("Bad signature in ");
1574     prepend += PrettyMethod(dex_method_idx_, *dex_file_);
1575     PrependToLastFailMessage(prepend);
1576     return false;
1577   }
1578   // We may have a runtime failure here, clear.
1579   have_pending_runtime_throw_failure_ = false;
1580 
1581   /* Perform code flow verification. */
1582   if (!CodeFlowVerifyMethod()) {
1583     DCHECK_NE(failures_.size(), 0U);
1584     return false;
1585   }
1586   return true;
1587 }
1588 
DumpFailures(std::ostream & os)1589 std::ostream& MethodVerifier::DumpFailures(std::ostream& os) {
1590   DCHECK_EQ(failures_.size(), failure_messages_.size());
1591   for (size_t i = 0; i < failures_.size(); ++i) {
1592       os << failure_messages_[i]->str() << "\n";
1593   }
1594   return os;
1595 }
1596 
Dump(std::ostream & os)1597 void MethodVerifier::Dump(std::ostream& os) {
1598   VariableIndentationOutputStream vios(&os);
1599   Dump(&vios);
1600 }
1601 
Dump(VariableIndentationOutputStream * vios)1602 void MethodVerifier::Dump(VariableIndentationOutputStream* vios) {
1603   if (code_item_ == nullptr) {
1604     vios->Stream() << "Native method\n";
1605     return;
1606   }
1607   {
1608     vios->Stream() << "Register Types:\n";
1609     ScopedIndentation indent1(vios);
1610     reg_types_.Dump(vios->Stream());
1611   }
1612   vios->Stream() << "Dumping instructions and register lines:\n";
1613   ScopedIndentation indent1(vios);
1614   const Instruction* inst = Instruction::At(code_item_->insns_);
1615   for (size_t dex_pc = 0; dex_pc < code_item_->insns_size_in_code_units_;
1616       dex_pc += inst->SizeInCodeUnits(), inst = inst->Next()) {
1617     RegisterLine* reg_line = reg_table_.GetLine(dex_pc);
1618     if (reg_line != nullptr) {
1619       vios->Stream() << reg_line->Dump(this) << "\n";
1620     }
1621     vios->Stream()
1622         << StringPrintf("0x%04zx", dex_pc) << ": " << GetInstructionFlags(dex_pc).ToString() << " ";
1623     const bool kDumpHexOfInstruction = false;
1624     if (kDumpHexOfInstruction) {
1625       vios->Stream() << inst->DumpHex(5) << " ";
1626     }
1627     vios->Stream() << inst->DumpString(dex_file_) << "\n";
1628   }
1629 }
1630 
IsPrimitiveDescriptor(char descriptor)1631 static bool IsPrimitiveDescriptor(char descriptor) {
1632   switch (descriptor) {
1633     case 'I':
1634     case 'C':
1635     case 'S':
1636     case 'B':
1637     case 'Z':
1638     case 'F':
1639     case 'D':
1640     case 'J':
1641       return true;
1642     default:
1643       return false;
1644   }
1645 }
1646 
SetTypesFromSignature()1647 bool MethodVerifier::SetTypesFromSignature() {
1648   RegisterLine* reg_line = reg_table_.GetLine(0);
1649 
1650   // Should have been verified earlier.
1651   DCHECK_GE(code_item_->registers_size_, code_item_->ins_size_);
1652 
1653   uint32_t arg_start = code_item_->registers_size_ - code_item_->ins_size_;
1654   size_t expected_args = code_item_->ins_size_;   /* long/double count as two */
1655 
1656   // Include the "this" pointer.
1657   size_t cur_arg = 0;
1658   if (!IsStatic()) {
1659     if (expected_args == 0) {
1660       // Expect at least a receiver.
1661       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "expected 0 args, but method is not static";
1662       return false;
1663     }
1664 
1665     // If this is a constructor for a class other than java.lang.Object, mark the first ("this")
1666     // argument as uninitialized. This restricts field access until the superclass constructor is
1667     // called.
1668     const RegType& declaring_class = GetDeclaringClass();
1669     if (IsConstructor()) {
1670       if (declaring_class.IsJavaLangObject()) {
1671         // "this" is implicitly initialized.
1672         reg_line->SetThisInitialized();
1673         reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, declaring_class);
1674       } else {
1675         reg_line->SetRegisterType<LockOp::kClear>(
1676             this,
1677             arg_start + cur_arg,
1678             reg_types_.UninitializedThisArgument(declaring_class));
1679       }
1680     } else {
1681       reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, declaring_class);
1682     }
1683     cur_arg++;
1684   }
1685 
1686   const DexFile::ProtoId& proto_id =
1687       dex_file_->GetMethodPrototype(dex_file_->GetMethodId(dex_method_idx_));
1688   DexFileParameterIterator iterator(*dex_file_, proto_id);
1689 
1690   for (; iterator.HasNext(); iterator.Next()) {
1691     const char* descriptor = iterator.GetDescriptor();
1692     if (descriptor == nullptr) {
1693       LOG(FATAL) << "Null descriptor";
1694     }
1695     if (cur_arg >= expected_args) {
1696       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "expected " << expected_args
1697                                         << " args, found more (" << descriptor << ")";
1698       return false;
1699     }
1700     switch (descriptor[0]) {
1701       case 'L':
1702       case '[':
1703         // We assume that reference arguments are initialized. The only way it could be otherwise
1704         // (assuming the caller was verified) is if the current method is <init>, but in that case
1705         // it's effectively considered initialized the instant we reach here (in the sense that we
1706         // can return without doing anything or call virtual methods).
1707         {
1708           const RegType& reg_type = ResolveClassAndCheckAccess(iterator.GetTypeIdx());
1709           if (!reg_type.IsNonZeroReferenceTypes()) {
1710             DCHECK(HasFailures());
1711             return false;
1712           }
1713           reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, reg_type);
1714         }
1715         break;
1716       case 'Z':
1717         reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, reg_types_.Boolean());
1718         break;
1719       case 'C':
1720         reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, reg_types_.Char());
1721         break;
1722       case 'B':
1723         reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, reg_types_.Byte());
1724         break;
1725       case 'I':
1726         reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, reg_types_.Integer());
1727         break;
1728       case 'S':
1729         reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, reg_types_.Short());
1730         break;
1731       case 'F':
1732         reg_line->SetRegisterType<LockOp::kClear>(this, arg_start + cur_arg, reg_types_.Float());
1733         break;
1734       case 'J':
1735       case 'D': {
1736         if (cur_arg + 1 >= expected_args) {
1737           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "expected " << expected_args
1738               << " args, found more (" << descriptor << ")";
1739           return false;
1740         }
1741 
1742         const RegType* lo_half;
1743         const RegType* hi_half;
1744         if (descriptor[0] == 'J') {
1745           lo_half = &reg_types_.LongLo();
1746           hi_half = &reg_types_.LongHi();
1747         } else {
1748           lo_half = &reg_types_.DoubleLo();
1749           hi_half = &reg_types_.DoubleHi();
1750         }
1751         reg_line->SetRegisterTypeWide(this, arg_start + cur_arg, *lo_half, *hi_half);
1752         cur_arg++;
1753         break;
1754       }
1755       default:
1756         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unexpected signature type char '"
1757                                           << descriptor << "'";
1758         return false;
1759     }
1760     cur_arg++;
1761   }
1762   if (cur_arg != expected_args) {
1763     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "expected " << expected_args
1764                                       << " arguments, found " << cur_arg;
1765     return false;
1766   }
1767   const char* descriptor = dex_file_->GetReturnTypeDescriptor(proto_id);
1768   // Validate return type. We don't do the type lookup; just want to make sure that it has the right
1769   // format. Only major difference from the method argument format is that 'V' is supported.
1770   bool result;
1771   if (IsPrimitiveDescriptor(descriptor[0]) || descriptor[0] == 'V') {
1772     result = descriptor[1] == '\0';
1773   } else if (descriptor[0] == '[') {  // single/multi-dimensional array of object/primitive
1774     size_t i = 0;
1775     do {
1776       i++;
1777     } while (descriptor[i] == '[');  // process leading [
1778     if (descriptor[i] == 'L') {  // object array
1779       do {
1780         i++;  // find closing ;
1781       } while (descriptor[i] != ';' && descriptor[i] != '\0');
1782       result = descriptor[i] == ';';
1783     } else {  // primitive array
1784       result = IsPrimitiveDescriptor(descriptor[i]) && descriptor[i + 1] == '\0';
1785     }
1786   } else if (descriptor[0] == 'L') {
1787     // could be more thorough here, but shouldn't be required
1788     size_t i = 0;
1789     do {
1790       i++;
1791     } while (descriptor[i] != ';' && descriptor[i] != '\0');
1792     result = descriptor[i] == ';';
1793   } else {
1794     result = false;
1795   }
1796   if (!result) {
1797     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unexpected char in return type descriptor '"
1798                                       << descriptor << "'";
1799   }
1800   return result;
1801 }
1802 
CodeFlowVerifyMethod()1803 bool MethodVerifier::CodeFlowVerifyMethod() {
1804   const uint16_t* insns = code_item_->insns_;
1805   const uint32_t insns_size = code_item_->insns_size_in_code_units_;
1806 
1807   /* Begin by marking the first instruction as "changed". */
1808   GetInstructionFlags(0).SetChanged();
1809   uint32_t start_guess = 0;
1810 
1811   /* Continue until no instructions are marked "changed". */
1812   while (true) {
1813     if (allow_thread_suspension_) {
1814       self_->AllowThreadSuspension();
1815     }
1816     // Find the first marked one. Use "start_guess" as a way to find one quickly.
1817     uint32_t insn_idx = start_guess;
1818     for (; insn_idx < insns_size; insn_idx++) {
1819       if (GetInstructionFlags(insn_idx).IsChanged())
1820         break;
1821     }
1822     if (insn_idx == insns_size) {
1823       if (start_guess != 0) {
1824         /* try again, starting from the top */
1825         start_guess = 0;
1826         continue;
1827       } else {
1828         /* all flags are clear */
1829         break;
1830       }
1831     }
1832     // We carry the working set of registers from instruction to instruction. If this address can
1833     // be the target of a branch (or throw) instruction, or if we're skipping around chasing
1834     // "changed" flags, we need to load the set of registers from the table.
1835     // Because we always prefer to continue on to the next instruction, we should never have a
1836     // situation where we have a stray "changed" flag set on an instruction that isn't a branch
1837     // target.
1838     work_insn_idx_ = insn_idx;
1839     if (GetInstructionFlags(insn_idx).IsBranchTarget()) {
1840       work_line_->CopyFromLine(reg_table_.GetLine(insn_idx));
1841     } else if (kIsDebugBuild) {
1842       /*
1843        * Sanity check: retrieve the stored register line (assuming
1844        * a full table) and make sure it actually matches.
1845        */
1846       RegisterLine* register_line = reg_table_.GetLine(insn_idx);
1847       if (register_line != nullptr) {
1848         if (work_line_->CompareLine(register_line) != 0) {
1849           Dump(std::cout);
1850           std::cout << info_messages_.str();
1851           LOG(FATAL) << "work_line diverged in " << PrettyMethod(dex_method_idx_, *dex_file_)
1852                      << "@" << reinterpret_cast<void*>(work_insn_idx_) << "\n"
1853                      << " work_line=" << work_line_->Dump(this) << "\n"
1854                      << "  expected=" << register_line->Dump(this);
1855         }
1856       }
1857     }
1858     if (!CodeFlowVerifyInstruction(&start_guess)) {
1859       std::string prepend(PrettyMethod(dex_method_idx_, *dex_file_));
1860       prepend += " failed to verify: ";
1861       PrependToLastFailMessage(prepend);
1862       return false;
1863     }
1864     /* Clear "changed" and mark as visited. */
1865     GetInstructionFlags(insn_idx).SetVisited();
1866     GetInstructionFlags(insn_idx).ClearChanged();
1867   }
1868 
1869   if (kDebugVerify) {
1870     /*
1871      * Scan for dead code. There's nothing "evil" about dead code
1872      * (besides the wasted space), but it indicates a flaw somewhere
1873      * down the line, possibly in the verifier.
1874      *
1875      * If we've substituted "always throw" instructions into the stream,
1876      * we are almost certainly going to have some dead code.
1877      */
1878     int dead_start = -1;
1879     uint32_t insn_idx = 0;
1880     for (; insn_idx < insns_size;
1881          insn_idx += Instruction::At(code_item_->insns_ + insn_idx)->SizeInCodeUnits()) {
1882       /*
1883        * Switch-statement data doesn't get "visited" by scanner. It
1884        * may or may not be preceded by a padding NOP (for alignment).
1885        */
1886       if (insns[insn_idx] == Instruction::kPackedSwitchSignature ||
1887           insns[insn_idx] == Instruction::kSparseSwitchSignature ||
1888           insns[insn_idx] == Instruction::kArrayDataSignature ||
1889           (insns[insn_idx] == Instruction::NOP && (insn_idx + 1 < insns_size) &&
1890            (insns[insn_idx + 1] == Instruction::kPackedSwitchSignature ||
1891             insns[insn_idx + 1] == Instruction::kSparseSwitchSignature ||
1892             insns[insn_idx + 1] == Instruction::kArrayDataSignature))) {
1893         GetInstructionFlags(insn_idx).SetVisited();
1894       }
1895 
1896       if (!GetInstructionFlags(insn_idx).IsVisited()) {
1897         if (dead_start < 0)
1898           dead_start = insn_idx;
1899       } else if (dead_start >= 0) {
1900         LogVerifyInfo() << "dead code " << reinterpret_cast<void*>(dead_start)
1901                         << "-" << reinterpret_cast<void*>(insn_idx - 1);
1902         dead_start = -1;
1903       }
1904     }
1905     if (dead_start >= 0) {
1906       LogVerifyInfo() << "dead code " << reinterpret_cast<void*>(dead_start)
1907                       << "-" << reinterpret_cast<void*>(insn_idx - 1);
1908     }
1909     // To dump the state of the verify after a method, do something like:
1910     // if (PrettyMethod(dex_method_idx_, *dex_file_) ==
1911     //     "boolean java.lang.String.equals(java.lang.Object)") {
1912     //   LOG(INFO) << info_messages_.str();
1913     // }
1914   }
1915   return true;
1916 }
1917 
1918 // Returns the index of the first final instance field of the given class, or kDexNoIndex if there
1919 // is no such field.
GetFirstFinalInstanceFieldIndex(const DexFile & dex_file,uint16_t type_idx)1920 static uint32_t GetFirstFinalInstanceFieldIndex(const DexFile& dex_file, uint16_t type_idx) {
1921   const DexFile::ClassDef* class_def = dex_file.FindClassDef(type_idx);
1922   DCHECK(class_def != nullptr);
1923   const uint8_t* class_data = dex_file.GetClassData(*class_def);
1924   DCHECK(class_data != nullptr);
1925   ClassDataItemIterator it(dex_file, class_data);
1926   // Skip static fields.
1927   while (it.HasNextStaticField()) {
1928     it.Next();
1929   }
1930   while (it.HasNextInstanceField()) {
1931     if ((it.GetFieldAccessFlags() & kAccFinal) != 0) {
1932       return it.GetMemberIndex();
1933     }
1934     it.Next();
1935   }
1936   return DexFile::kDexNoIndex;
1937 }
1938 
1939 // Setup a register line for the given return instruction.
AdjustReturnLine(MethodVerifier * verifier,const Instruction * ret_inst,RegisterLine * line)1940 static void AdjustReturnLine(MethodVerifier* verifier,
1941                              const Instruction* ret_inst,
1942                              RegisterLine* line) {
1943   Instruction::Code opcode = ret_inst->Opcode();
1944 
1945   switch (opcode) {
1946     case Instruction::RETURN_VOID:
1947     case Instruction::RETURN_VOID_NO_BARRIER:
1948       SafelyMarkAllRegistersAsConflicts(verifier, line);
1949       break;
1950 
1951     case Instruction::RETURN:
1952     case Instruction::RETURN_OBJECT:
1953       line->MarkAllRegistersAsConflictsExcept(verifier, ret_inst->VRegA_11x());
1954       break;
1955 
1956     case Instruction::RETURN_WIDE:
1957       line->MarkAllRegistersAsConflictsExceptWide(verifier, ret_inst->VRegA_11x());
1958       break;
1959 
1960     default:
1961       LOG(FATAL) << "Unknown return opcode " << opcode;
1962       UNREACHABLE();
1963   }
1964 }
1965 
CodeFlowVerifyInstruction(uint32_t * start_guess)1966 bool MethodVerifier::CodeFlowVerifyInstruction(uint32_t* start_guess) {
1967   // If we're doing FindLocksAtDexPc, check whether we're at the dex pc we care about.
1968   // We want the state _before_ the instruction, for the case where the dex pc we're
1969   // interested in is itself a monitor-enter instruction (which is a likely place
1970   // for a thread to be suspended).
1971   if (monitor_enter_dex_pcs_ != nullptr && work_insn_idx_ == interesting_dex_pc_) {
1972     monitor_enter_dex_pcs_->clear();  // The new work line is more accurate than the previous one.
1973     for (size_t i = 0; i < work_line_->GetMonitorEnterCount(); ++i) {
1974       monitor_enter_dex_pcs_->push_back(work_line_->GetMonitorEnterDexPc(i));
1975     }
1976   }
1977 
1978   /*
1979    * Once we finish decoding the instruction, we need to figure out where
1980    * we can go from here. There are three possible ways to transfer
1981    * control to another statement:
1982    *
1983    * (1) Continue to the next instruction. Applies to all but
1984    *     unconditional branches, method returns, and exception throws.
1985    * (2) Branch to one or more possible locations. Applies to branches
1986    *     and switch statements.
1987    * (3) Exception handlers. Applies to any instruction that can
1988    *     throw an exception that is handled by an encompassing "try"
1989    *     block.
1990    *
1991    * We can also return, in which case there is no successor instruction
1992    * from this point.
1993    *
1994    * The behavior can be determined from the opcode flags.
1995    */
1996   const uint16_t* insns = code_item_->insns_ + work_insn_idx_;
1997   const Instruction* inst = Instruction::At(insns);
1998   int opcode_flags = Instruction::FlagsOf(inst->Opcode());
1999 
2000   int32_t branch_target = 0;
2001   bool just_set_result = false;
2002   if (kDebugVerify) {
2003     // Generate processing back trace to debug verifier
2004     LogVerifyInfo() << "Processing " << inst->DumpString(dex_file_) << "\n"
2005                     << work_line_->Dump(this) << "\n";
2006   }
2007 
2008   /*
2009    * Make a copy of the previous register state. If the instruction
2010    * can throw an exception, we will copy/merge this into the "catch"
2011    * address rather than work_line, because we don't want the result
2012    * from the "successful" code path (e.g. a check-cast that "improves"
2013    * a type) to be visible to the exception handler.
2014    */
2015   if ((opcode_flags & Instruction::kThrow) != 0 && CurrentInsnFlags()->IsInTry()) {
2016     saved_line_->CopyFromLine(work_line_.get());
2017   } else if (kIsDebugBuild) {
2018     saved_line_->FillWithGarbage();
2019   }
2020   DCHECK(!have_pending_runtime_throw_failure_);  // Per-instruction flag, should not be set here.
2021 
2022 
2023   // We need to ensure the work line is consistent while performing validation. When we spot a
2024   // peephole pattern we compute a new line for either the fallthrough instruction or the
2025   // branch target.
2026   RegisterLineArenaUniquePtr branch_line;
2027   RegisterLineArenaUniquePtr fallthrough_line;
2028 
2029   switch (inst->Opcode()) {
2030     case Instruction::NOP:
2031       /*
2032        * A "pure" NOP has no effect on anything. Data tables start with
2033        * a signature that looks like a NOP; if we see one of these in
2034        * the course of executing code then we have a problem.
2035        */
2036       if (inst->VRegA_10x() != 0) {
2037         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "encountered data table in instruction stream";
2038       }
2039       break;
2040 
2041     case Instruction::MOVE:
2042       work_line_->CopyRegister1(this, inst->VRegA_12x(), inst->VRegB_12x(), kTypeCategory1nr);
2043       break;
2044     case Instruction::MOVE_FROM16:
2045       work_line_->CopyRegister1(this, inst->VRegA_22x(), inst->VRegB_22x(), kTypeCategory1nr);
2046       break;
2047     case Instruction::MOVE_16:
2048       work_line_->CopyRegister1(this, inst->VRegA_32x(), inst->VRegB_32x(), kTypeCategory1nr);
2049       break;
2050     case Instruction::MOVE_WIDE:
2051       work_line_->CopyRegister2(this, inst->VRegA_12x(), inst->VRegB_12x());
2052       break;
2053     case Instruction::MOVE_WIDE_FROM16:
2054       work_line_->CopyRegister2(this, inst->VRegA_22x(), inst->VRegB_22x());
2055       break;
2056     case Instruction::MOVE_WIDE_16:
2057       work_line_->CopyRegister2(this, inst->VRegA_32x(), inst->VRegB_32x());
2058       break;
2059     case Instruction::MOVE_OBJECT:
2060       work_line_->CopyRegister1(this, inst->VRegA_12x(), inst->VRegB_12x(), kTypeCategoryRef);
2061       break;
2062     case Instruction::MOVE_OBJECT_FROM16:
2063       work_line_->CopyRegister1(this, inst->VRegA_22x(), inst->VRegB_22x(), kTypeCategoryRef);
2064       break;
2065     case Instruction::MOVE_OBJECT_16:
2066       work_line_->CopyRegister1(this, inst->VRegA_32x(), inst->VRegB_32x(), kTypeCategoryRef);
2067       break;
2068 
2069     /*
2070      * The move-result instructions copy data out of a "pseudo-register"
2071      * with the results from the last method invocation. In practice we
2072      * might want to hold the result in an actual CPU register, so the
2073      * Dalvik spec requires that these only appear immediately after an
2074      * invoke or filled-new-array.
2075      *
2076      * These calls invalidate the "result" register. (This is now
2077      * redundant with the reset done below, but it can make the debug info
2078      * easier to read in some cases.)
2079      */
2080     case Instruction::MOVE_RESULT:
2081       work_line_->CopyResultRegister1(this, inst->VRegA_11x(), false);
2082       break;
2083     case Instruction::MOVE_RESULT_WIDE:
2084       work_line_->CopyResultRegister2(this, inst->VRegA_11x());
2085       break;
2086     case Instruction::MOVE_RESULT_OBJECT:
2087       work_line_->CopyResultRegister1(this, inst->VRegA_11x(), true);
2088       break;
2089 
2090     case Instruction::MOVE_EXCEPTION: {
2091       // We do not allow MOVE_EXCEPTION as the first instruction in a method. This is a simple case
2092       // where one entrypoint to the catch block is not actually an exception path.
2093       if (work_insn_idx_ == 0) {
2094         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "move-exception at pc 0x0";
2095         break;
2096       }
2097       /*
2098        * This statement can only appear as the first instruction in an exception handler. We verify
2099        * that as part of extracting the exception type from the catch block list.
2100        */
2101       const RegType& res_type = GetCaughtExceptionType();
2102       work_line_->SetRegisterType<LockOp::kClear>(this, inst->VRegA_11x(), res_type);
2103       break;
2104     }
2105     case Instruction::RETURN_VOID:
2106       if (!IsInstanceConstructor() || work_line_->CheckConstructorReturn(this)) {
2107         if (!GetMethodReturnType().IsConflict()) {
2108           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "return-void not expected";
2109         }
2110       }
2111       break;
2112     case Instruction::RETURN:
2113       if (!IsInstanceConstructor() || work_line_->CheckConstructorReturn(this)) {
2114         /* check the method signature */
2115         const RegType& return_type = GetMethodReturnType();
2116         if (!return_type.IsCategory1Types()) {
2117           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unexpected non-category 1 return type "
2118                                             << return_type;
2119         } else {
2120           // Compilers may generate synthetic functions that write byte values into boolean fields.
2121           // Also, it may use integer values for boolean, byte, short, and character return types.
2122           const uint32_t vregA = inst->VRegA_11x();
2123           const RegType& src_type = work_line_->GetRegisterType(this, vregA);
2124           bool use_src = ((return_type.IsBoolean() && src_type.IsByte()) ||
2125                           ((return_type.IsBoolean() || return_type.IsByte() ||
2126                            return_type.IsShort() || return_type.IsChar()) &&
2127                            src_type.IsInteger()));
2128           /* check the register contents */
2129           bool success =
2130               work_line_->VerifyRegisterType(this, vregA, use_src ? src_type : return_type);
2131           if (!success) {
2132             AppendToLastFailMessage(StringPrintf(" return-1nr on invalid register v%d", vregA));
2133           }
2134         }
2135       }
2136       break;
2137     case Instruction::RETURN_WIDE:
2138       if (!IsInstanceConstructor() || work_line_->CheckConstructorReturn(this)) {
2139         /* check the method signature */
2140         const RegType& return_type = GetMethodReturnType();
2141         if (!return_type.IsCategory2Types()) {
2142           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "return-wide not expected";
2143         } else {
2144           /* check the register contents */
2145           const uint32_t vregA = inst->VRegA_11x();
2146           bool success = work_line_->VerifyRegisterType(this, vregA, return_type);
2147           if (!success) {
2148             AppendToLastFailMessage(StringPrintf(" return-wide on invalid register v%d", vregA));
2149           }
2150         }
2151       }
2152       break;
2153     case Instruction::RETURN_OBJECT:
2154       if (!IsInstanceConstructor() || work_line_->CheckConstructorReturn(this)) {
2155         const RegType& return_type = GetMethodReturnType();
2156         if (!return_type.IsReferenceTypes()) {
2157           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "return-object not expected";
2158         } else {
2159           /* return_type is the *expected* return type, not register value */
2160           DCHECK(!return_type.IsZero());
2161           DCHECK(!return_type.IsUninitializedReference());
2162           const uint32_t vregA = inst->VRegA_11x();
2163           const RegType& reg_type = work_line_->GetRegisterType(this, vregA);
2164           // Disallow returning undefined, conflict & uninitialized values and verify that the
2165           // reference in vAA is an instance of the "return_type."
2166           if (reg_type.IsUndefined()) {
2167             Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "returning undefined register";
2168           } else if (reg_type.IsConflict()) {
2169             Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "returning register with conflict";
2170           } else if (reg_type.IsUninitializedTypes()) {
2171             Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "returning uninitialized object '"
2172                                               << reg_type << "'";
2173           } else if (!reg_type.IsReferenceTypes()) {
2174             // We really do expect a reference here.
2175             Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "return-object returns a non-reference type "
2176                                               << reg_type;
2177           } else if (!return_type.IsAssignableFrom(reg_type)) {
2178             if (reg_type.IsUnresolvedTypes() || return_type.IsUnresolvedTypes()) {
2179               Fail(VERIFY_ERROR_NO_CLASS) << " can't resolve returned type '" << return_type
2180                   << "' or '" << reg_type << "'";
2181             } else {
2182               bool soft_error = false;
2183               // Check whether arrays are involved. They will show a valid class status, even
2184               // if their components are erroneous.
2185               if (reg_type.IsArrayTypes() && return_type.IsArrayTypes()) {
2186                 return_type.CanAssignArray(reg_type, reg_types_, class_loader_, &soft_error);
2187                 if (soft_error) {
2188                   Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "array with erroneous component type: "
2189                         << reg_type << " vs " << return_type;
2190                 }
2191               }
2192 
2193               if (!soft_error) {
2194                 Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "returning '" << reg_type
2195                     << "', but expected from declaration '" << return_type << "'";
2196               }
2197             }
2198           }
2199         }
2200       }
2201       break;
2202 
2203       /* could be boolean, int, float, or a null reference */
2204     case Instruction::CONST_4: {
2205       int32_t val = static_cast<int32_t>(inst->VRegB_11n() << 28) >> 28;
2206       work_line_->SetRegisterType<LockOp::kClear>(
2207           this, inst->VRegA_11n(), DetermineCat1Constant(val, need_precise_constants_));
2208       break;
2209     }
2210     case Instruction::CONST_16: {
2211       int16_t val = static_cast<int16_t>(inst->VRegB_21s());
2212       work_line_->SetRegisterType<LockOp::kClear>(
2213           this, inst->VRegA_21s(), DetermineCat1Constant(val, need_precise_constants_));
2214       break;
2215     }
2216     case Instruction::CONST: {
2217       int32_t val = inst->VRegB_31i();
2218       work_line_->SetRegisterType<LockOp::kClear>(
2219           this, inst->VRegA_31i(), DetermineCat1Constant(val, need_precise_constants_));
2220       break;
2221     }
2222     case Instruction::CONST_HIGH16: {
2223       int32_t val = static_cast<int32_t>(inst->VRegB_21h() << 16);
2224       work_line_->SetRegisterType<LockOp::kClear>(
2225           this, inst->VRegA_21h(), DetermineCat1Constant(val, need_precise_constants_));
2226       break;
2227     }
2228       /* could be long or double; resolved upon use */
2229     case Instruction::CONST_WIDE_16: {
2230       int64_t val = static_cast<int16_t>(inst->VRegB_21s());
2231       const RegType& lo = reg_types_.FromCat2ConstLo(static_cast<int32_t>(val), true);
2232       const RegType& hi = reg_types_.FromCat2ConstHi(static_cast<int32_t>(val >> 32), true);
2233       work_line_->SetRegisterTypeWide(this, inst->VRegA_21s(), lo, hi);
2234       break;
2235     }
2236     case Instruction::CONST_WIDE_32: {
2237       int64_t val = static_cast<int32_t>(inst->VRegB_31i());
2238       const RegType& lo = reg_types_.FromCat2ConstLo(static_cast<int32_t>(val), true);
2239       const RegType& hi = reg_types_.FromCat2ConstHi(static_cast<int32_t>(val >> 32), true);
2240       work_line_->SetRegisterTypeWide(this, inst->VRegA_31i(), lo, hi);
2241       break;
2242     }
2243     case Instruction::CONST_WIDE: {
2244       int64_t val = inst->VRegB_51l();
2245       const RegType& lo = reg_types_.FromCat2ConstLo(static_cast<int32_t>(val), true);
2246       const RegType& hi = reg_types_.FromCat2ConstHi(static_cast<int32_t>(val >> 32), true);
2247       work_line_->SetRegisterTypeWide(this, inst->VRegA_51l(), lo, hi);
2248       break;
2249     }
2250     case Instruction::CONST_WIDE_HIGH16: {
2251       int64_t val = static_cast<uint64_t>(inst->VRegB_21h()) << 48;
2252       const RegType& lo = reg_types_.FromCat2ConstLo(static_cast<int32_t>(val), true);
2253       const RegType& hi = reg_types_.FromCat2ConstHi(static_cast<int32_t>(val >> 32), true);
2254       work_line_->SetRegisterTypeWide(this, inst->VRegA_21h(), lo, hi);
2255       break;
2256     }
2257     case Instruction::CONST_STRING:
2258       work_line_->SetRegisterType<LockOp::kClear>(
2259           this, inst->VRegA_21c(), reg_types_.JavaLangString());
2260       break;
2261     case Instruction::CONST_STRING_JUMBO:
2262       work_line_->SetRegisterType<LockOp::kClear>(
2263           this, inst->VRegA_31c(), reg_types_.JavaLangString());
2264       break;
2265     case Instruction::CONST_CLASS: {
2266       // Get type from instruction if unresolved then we need an access check
2267       // TODO: check Compiler::CanAccessTypeWithoutChecks returns false when res_type is unresolved
2268       const RegType& res_type = ResolveClassAndCheckAccess(inst->VRegB_21c());
2269       // Register holds class, ie its type is class, on error it will hold Conflict.
2270       work_line_->SetRegisterType<LockOp::kClear>(
2271           this, inst->VRegA_21c(), res_type.IsConflict() ? res_type
2272                                                          : reg_types_.JavaLangClass());
2273       break;
2274     }
2275     case Instruction::MONITOR_ENTER:
2276       work_line_->PushMonitor(this, inst->VRegA_11x(), work_insn_idx_);
2277       // Check whether the previous instruction is a move-object with vAA as a source, creating
2278       // untracked lock aliasing.
2279       if (0 != work_insn_idx_ && !GetInstructionFlags(work_insn_idx_).IsBranchTarget()) {
2280         uint32_t prev_idx = work_insn_idx_ - 1;
2281         while (0 != prev_idx && !GetInstructionFlags(prev_idx).IsOpcode()) {
2282           prev_idx--;
2283         }
2284         const Instruction* prev_inst = Instruction::At(code_item_->insns_ + prev_idx);
2285         switch (prev_inst->Opcode()) {
2286           case Instruction::MOVE_OBJECT:
2287           case Instruction::MOVE_OBJECT_16:
2288           case Instruction::MOVE_OBJECT_FROM16:
2289             if (prev_inst->VRegB() == inst->VRegA_11x()) {
2290               // Redo the copy. This won't change the register types, but update the lock status
2291               // for the aliased register.
2292               work_line_->CopyRegister1(this,
2293                                         prev_inst->VRegA(),
2294                                         prev_inst->VRegB(),
2295                                         kTypeCategoryRef);
2296             }
2297             break;
2298 
2299           default:  // Other instruction types ignored.
2300             break;
2301         }
2302       }
2303       break;
2304     case Instruction::MONITOR_EXIT:
2305       /*
2306        * monitor-exit instructions are odd. They can throw exceptions,
2307        * but when they do they act as if they succeeded and the PC is
2308        * pointing to the following instruction. (This behavior goes back
2309        * to the need to handle asynchronous exceptions, a now-deprecated
2310        * feature that Dalvik doesn't support.)
2311        *
2312        * In practice we don't need to worry about this. The only
2313        * exceptions that can be thrown from monitor-exit are for a
2314        * null reference and -exit without a matching -enter. If the
2315        * structured locking checks are working, the former would have
2316        * failed on the -enter instruction, and the latter is impossible.
2317        *
2318        * This is fortunate, because issue 3221411 prevents us from
2319        * chasing the "can throw" path when monitor verification is
2320        * enabled. If we can fully verify the locking we can ignore
2321        * some catch blocks (which will show up as "dead" code when
2322        * we skip them here); if we can't, then the code path could be
2323        * "live" so we still need to check it.
2324        */
2325       opcode_flags &= ~Instruction::kThrow;
2326       work_line_->PopMonitor(this, inst->VRegA_11x());
2327       break;
2328     case Instruction::CHECK_CAST:
2329     case Instruction::INSTANCE_OF: {
2330       /*
2331        * If this instruction succeeds, we will "downcast" register vA to the type in vB. (This
2332        * could be a "upcast" -- not expected, so we don't try to address it.)
2333        *
2334        * If it fails, an exception is thrown, which we deal with later by ignoring the update to
2335        * dec_insn.vA when branching to a handler.
2336        */
2337       const bool is_checkcast = (inst->Opcode() == Instruction::CHECK_CAST);
2338       const uint32_t type_idx = (is_checkcast) ? inst->VRegB_21c() : inst->VRegC_22c();
2339       const RegType& res_type = ResolveClassAndCheckAccess(type_idx);
2340       if (res_type.IsConflict()) {
2341         // If this is a primitive type, fail HARD.
2342         mirror::Class* klass = dex_cache_->GetResolvedType(type_idx);
2343         if (klass != nullptr && klass->IsPrimitive()) {
2344           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "using primitive type "
2345               << dex_file_->StringByTypeIdx(type_idx) << " in instanceof in "
2346               << GetDeclaringClass();
2347           break;
2348         }
2349 
2350         DCHECK_NE(failures_.size(), 0U);
2351         if (!is_checkcast) {
2352           work_line_->SetRegisterType<LockOp::kClear>(this,
2353                                                       inst->VRegA_22c(),
2354                                                       reg_types_.Boolean());
2355         }
2356         break;  // bad class
2357       }
2358       // TODO: check Compiler::CanAccessTypeWithoutChecks returns false when res_type is unresolved
2359       uint32_t orig_type_reg = (is_checkcast) ? inst->VRegA_21c() : inst->VRegB_22c();
2360       const RegType& orig_type = work_line_->GetRegisterType(this, orig_type_reg);
2361       if (!res_type.IsNonZeroReferenceTypes()) {
2362         if (is_checkcast) {
2363           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "check-cast on unexpected class " << res_type;
2364         } else {
2365           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "instance-of on unexpected class " << res_type;
2366         }
2367       } else if (!orig_type.IsReferenceTypes()) {
2368         if (is_checkcast) {
2369           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "check-cast on non-reference in v" << orig_type_reg;
2370         } else {
2371           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "instance-of on non-reference in v" << orig_type_reg;
2372         }
2373       } else if (orig_type.IsUninitializedTypes()) {
2374         if (is_checkcast) {
2375           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "check-cast on uninitialized reference in v"
2376                                             << orig_type_reg;
2377         } else {
2378           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "instance-of on uninitialized reference in v"
2379                                             << orig_type_reg;
2380         }
2381       } else {
2382         if (is_checkcast) {
2383           work_line_->SetRegisterType<LockOp::kKeep>(this, inst->VRegA_21c(), res_type);
2384         } else {
2385           work_line_->SetRegisterType<LockOp::kClear>(this,
2386                                                       inst->VRegA_22c(),
2387                                                       reg_types_.Boolean());
2388         }
2389       }
2390       break;
2391     }
2392     case Instruction::ARRAY_LENGTH: {
2393       const RegType& res_type = work_line_->GetRegisterType(this, inst->VRegB_12x());
2394       if (res_type.IsReferenceTypes()) {
2395         if (!res_type.IsArrayTypes() && !res_type.IsZero()) {  // ie not an array or null
2396           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "array-length on non-array " << res_type;
2397         } else {
2398           work_line_->SetRegisterType<LockOp::kClear>(this,
2399                                                       inst->VRegA_12x(),
2400                                                       reg_types_.Integer());
2401         }
2402       } else {
2403         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "array-length on non-array " << res_type;
2404       }
2405       break;
2406     }
2407     case Instruction::NEW_INSTANCE: {
2408       const RegType& res_type = ResolveClassAndCheckAccess(inst->VRegB_21c());
2409       if (res_type.IsConflict()) {
2410         DCHECK_NE(failures_.size(), 0U);
2411         break;  // bad class
2412       }
2413       // TODO: check Compiler::CanAccessTypeWithoutChecks returns false when res_type is unresolved
2414       // can't create an instance of an interface or abstract class */
2415       if (!res_type.IsInstantiableTypes()) {
2416         Fail(VERIFY_ERROR_INSTANTIATION)
2417             << "new-instance on primitive, interface or abstract class" << res_type;
2418         // Soft failure so carry on to set register type.
2419       }
2420       const RegType& uninit_type = reg_types_.Uninitialized(res_type, work_insn_idx_);
2421       // Any registers holding previous allocations from this address that have not yet been
2422       // initialized must be marked invalid.
2423       work_line_->MarkUninitRefsAsInvalid(this, uninit_type);
2424       // add the new uninitialized reference to the register state
2425       work_line_->SetRegisterType<LockOp::kClear>(this, inst->VRegA_21c(), uninit_type);
2426       break;
2427     }
2428     case Instruction::NEW_ARRAY:
2429       VerifyNewArray(inst, false, false);
2430       break;
2431     case Instruction::FILLED_NEW_ARRAY:
2432       VerifyNewArray(inst, true, false);
2433       just_set_result = true;  // Filled new array sets result register
2434       break;
2435     case Instruction::FILLED_NEW_ARRAY_RANGE:
2436       VerifyNewArray(inst, true, true);
2437       just_set_result = true;  // Filled new array range sets result register
2438       break;
2439     case Instruction::CMPL_FLOAT:
2440     case Instruction::CMPG_FLOAT:
2441       if (!work_line_->VerifyRegisterType(this, inst->VRegB_23x(), reg_types_.Float())) {
2442         break;
2443       }
2444       if (!work_line_->VerifyRegisterType(this, inst->VRegC_23x(), reg_types_.Float())) {
2445         break;
2446       }
2447       work_line_->SetRegisterType<LockOp::kClear>(this, inst->VRegA_23x(), reg_types_.Integer());
2448       break;
2449     case Instruction::CMPL_DOUBLE:
2450     case Instruction::CMPG_DOUBLE:
2451       if (!work_line_->VerifyRegisterTypeWide(this, inst->VRegB_23x(), reg_types_.DoubleLo(),
2452                                               reg_types_.DoubleHi())) {
2453         break;
2454       }
2455       if (!work_line_->VerifyRegisterTypeWide(this, inst->VRegC_23x(), reg_types_.DoubleLo(),
2456                                               reg_types_.DoubleHi())) {
2457         break;
2458       }
2459       work_line_->SetRegisterType<LockOp::kClear>(this, inst->VRegA_23x(), reg_types_.Integer());
2460       break;
2461     case Instruction::CMP_LONG:
2462       if (!work_line_->VerifyRegisterTypeWide(this, inst->VRegB_23x(), reg_types_.LongLo(),
2463                                               reg_types_.LongHi())) {
2464         break;
2465       }
2466       if (!work_line_->VerifyRegisterTypeWide(this, inst->VRegC_23x(), reg_types_.LongLo(),
2467                                               reg_types_.LongHi())) {
2468         break;
2469       }
2470       work_line_->SetRegisterType<LockOp::kClear>(this, inst->VRegA_23x(), reg_types_.Integer());
2471       break;
2472     case Instruction::THROW: {
2473       const RegType& res_type = work_line_->GetRegisterType(this, inst->VRegA_11x());
2474       if (!reg_types_.JavaLangThrowable(false).IsAssignableFrom(res_type)) {
2475         if (res_type.IsUninitializedTypes()) {
2476           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "thrown exception not initialized";
2477         } else if (!res_type.IsReferenceTypes()) {
2478           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "thrown value of non-reference type " << res_type;
2479         } else {
2480           Fail(res_type.IsUnresolvedTypes() ? VERIFY_ERROR_NO_CLASS : VERIFY_ERROR_BAD_CLASS_SOFT)
2481                 << "thrown class " << res_type << " not instanceof Throwable";
2482         }
2483       }
2484       break;
2485     }
2486     case Instruction::GOTO:
2487     case Instruction::GOTO_16:
2488     case Instruction::GOTO_32:
2489       /* no effect on or use of registers */
2490       break;
2491 
2492     case Instruction::PACKED_SWITCH:
2493     case Instruction::SPARSE_SWITCH:
2494       /* verify that vAA is an integer, or can be converted to one */
2495       work_line_->VerifyRegisterType(this, inst->VRegA_31t(), reg_types_.Integer());
2496       break;
2497 
2498     case Instruction::FILL_ARRAY_DATA: {
2499       /* Similar to the verification done for APUT */
2500       const RegType& array_type = work_line_->GetRegisterType(this, inst->VRegA_31t());
2501       /* array_type can be null if the reg type is Zero */
2502       if (!array_type.IsZero()) {
2503         if (!array_type.IsArrayTypes()) {
2504           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid fill-array-data with array type "
2505                                             << array_type;
2506         } else if (array_type.IsUnresolvedTypes()) {
2507           // If it's an unresolved array type, it must be non-primitive.
2508           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid fill-array-data for array of type "
2509                                             << array_type;
2510         } else {
2511           const RegType& component_type = reg_types_.GetComponentType(array_type, GetClassLoader());
2512           DCHECK(!component_type.IsConflict());
2513           if (component_type.IsNonZeroReferenceTypes()) {
2514             Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid fill-array-data with component type "
2515                                               << component_type;
2516           } else {
2517             // Now verify if the element width in the table matches the element width declared in
2518             // the array
2519             const uint16_t* array_data =
2520                 insns + (insns[1] | (static_cast<int32_t>(insns[2]) << 16));
2521             if (array_data[0] != Instruction::kArrayDataSignature) {
2522               Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid magic for array-data";
2523             } else {
2524               size_t elem_width = Primitive::ComponentSize(component_type.GetPrimitiveType());
2525               // Since we don't compress the data in Dex, expect to see equal width of data stored
2526               // in the table and expected from the array class.
2527               if (array_data[1] != elem_width) {
2528                 Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "array-data size mismatch (" << array_data[1]
2529                                                   << " vs " << elem_width << ")";
2530               }
2531             }
2532           }
2533         }
2534       }
2535       break;
2536     }
2537     case Instruction::IF_EQ:
2538     case Instruction::IF_NE: {
2539       const RegType& reg_type1 = work_line_->GetRegisterType(this, inst->VRegA_22t());
2540       const RegType& reg_type2 = work_line_->GetRegisterType(this, inst->VRegB_22t());
2541       bool mismatch = false;
2542       if (reg_type1.IsZero()) {  // zero then integral or reference expected
2543         mismatch = !reg_type2.IsReferenceTypes() && !reg_type2.IsIntegralTypes();
2544       } else if (reg_type1.IsReferenceTypes()) {  // both references?
2545         mismatch = !reg_type2.IsReferenceTypes();
2546       } else {  // both integral?
2547         mismatch = !reg_type1.IsIntegralTypes() || !reg_type2.IsIntegralTypes();
2548       }
2549       if (mismatch) {
2550         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "args to if-eq/if-ne (" << reg_type1 << ","
2551                                           << reg_type2 << ") must both be references or integral";
2552       }
2553       break;
2554     }
2555     case Instruction::IF_LT:
2556     case Instruction::IF_GE:
2557     case Instruction::IF_GT:
2558     case Instruction::IF_LE: {
2559       const RegType& reg_type1 = work_line_->GetRegisterType(this, inst->VRegA_22t());
2560       const RegType& reg_type2 = work_line_->GetRegisterType(this, inst->VRegB_22t());
2561       if (!reg_type1.IsIntegralTypes() || !reg_type2.IsIntegralTypes()) {
2562         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "args to 'if' (" << reg_type1 << ","
2563                                           << reg_type2 << ") must be integral";
2564       }
2565       break;
2566     }
2567     case Instruction::IF_EQZ:
2568     case Instruction::IF_NEZ: {
2569       const RegType& reg_type = work_line_->GetRegisterType(this, inst->VRegA_21t());
2570       if (!reg_type.IsReferenceTypes() && !reg_type.IsIntegralTypes()) {
2571         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "type " << reg_type
2572                                           << " unexpected as arg to if-eqz/if-nez";
2573       }
2574 
2575       // Find previous instruction - its existence is a precondition to peephole optimization.
2576       uint32_t instance_of_idx = 0;
2577       if (0 != work_insn_idx_) {
2578         instance_of_idx = work_insn_idx_ - 1;
2579         while (0 != instance_of_idx && !GetInstructionFlags(instance_of_idx).IsOpcode()) {
2580           instance_of_idx--;
2581         }
2582         if (FailOrAbort(this, GetInstructionFlags(instance_of_idx).IsOpcode(),
2583                         "Unable to get previous instruction of if-eqz/if-nez for work index ",
2584                         work_insn_idx_)) {
2585           break;
2586         }
2587       } else {
2588         break;
2589       }
2590 
2591       const Instruction* instance_of_inst = Instruction::At(code_item_->insns_ + instance_of_idx);
2592 
2593       /* Check for peep-hole pattern of:
2594        *    ...;
2595        *    instance-of vX, vY, T;
2596        *    ifXXX vX, label ;
2597        *    ...;
2598        * label:
2599        *    ...;
2600        * and sharpen the type of vY to be type T.
2601        * Note, this pattern can't be if:
2602        *  - if there are other branches to this branch,
2603        *  - when vX == vY.
2604        */
2605       if (!CurrentInsnFlags()->IsBranchTarget() &&
2606           (Instruction::INSTANCE_OF == instance_of_inst->Opcode()) &&
2607           (inst->VRegA_21t() == instance_of_inst->VRegA_22c()) &&
2608           (instance_of_inst->VRegA_22c() != instance_of_inst->VRegB_22c())) {
2609         // Check the type of the instance-of is different than that of registers type, as if they
2610         // are the same there is no work to be done here. Check that the conversion is not to or
2611         // from an unresolved type as type information is imprecise. If the instance-of is to an
2612         // interface then ignore the type information as interfaces can only be treated as Objects
2613         // and we don't want to disallow field and other operations on the object. If the value
2614         // being instance-of checked against is known null (zero) then allow the optimization as
2615         // we didn't have type information. If the merge of the instance-of type with the original
2616         // type is assignable to the original then allow optimization. This check is performed to
2617         // ensure that subsequent merges don't lose type information - such as becoming an
2618         // interface from a class that would lose information relevant to field checks.
2619         const RegType& orig_type = work_line_->GetRegisterType(this, instance_of_inst->VRegB_22c());
2620         const RegType& cast_type = ResolveClassAndCheckAccess(instance_of_inst->VRegC_22c());
2621 
2622         if (!orig_type.Equals(cast_type) &&
2623             !cast_type.IsUnresolvedTypes() && !orig_type.IsUnresolvedTypes() &&
2624             cast_type.HasClass() &&             // Could be conflict type, make sure it has a class.
2625             !cast_type.GetClass()->IsInterface() &&
2626             (orig_type.IsZero() ||
2627                 orig_type.IsStrictlyAssignableFrom(cast_type.Merge(orig_type, &reg_types_)))) {
2628           RegisterLine* update_line = RegisterLine::Create(code_item_->registers_size_, this);
2629           if (inst->Opcode() == Instruction::IF_EQZ) {
2630             fallthrough_line.reset(update_line);
2631           } else {
2632             branch_line.reset(update_line);
2633           }
2634           update_line->CopyFromLine(work_line_.get());
2635           update_line->SetRegisterType<LockOp::kKeep>(this,
2636                                                       instance_of_inst->VRegB_22c(),
2637                                                       cast_type);
2638           if (!GetInstructionFlags(instance_of_idx).IsBranchTarget() && 0 != instance_of_idx) {
2639             // See if instance-of was preceded by a move-object operation, common due to the small
2640             // register encoding space of instance-of, and propagate type information to the source
2641             // of the move-object.
2642             uint32_t move_idx = instance_of_idx - 1;
2643             while (0 != move_idx && !GetInstructionFlags(move_idx).IsOpcode()) {
2644               move_idx--;
2645             }
2646             if (FailOrAbort(this, GetInstructionFlags(move_idx).IsOpcode(),
2647                             "Unable to get previous instruction of if-eqz/if-nez for work index ",
2648                             work_insn_idx_)) {
2649               break;
2650             }
2651             const Instruction* move_inst = Instruction::At(code_item_->insns_ + move_idx);
2652             switch (move_inst->Opcode()) {
2653               case Instruction::MOVE_OBJECT:
2654                 if (move_inst->VRegA_12x() == instance_of_inst->VRegB_22c()) {
2655                   update_line->SetRegisterType<LockOp::kKeep>(this,
2656                                                               move_inst->VRegB_12x(),
2657                                                               cast_type);
2658                 }
2659                 break;
2660               case Instruction::MOVE_OBJECT_FROM16:
2661                 if (move_inst->VRegA_22x() == instance_of_inst->VRegB_22c()) {
2662                   update_line->SetRegisterType<LockOp::kKeep>(this,
2663                                                               move_inst->VRegB_22x(),
2664                                                               cast_type);
2665                 }
2666                 break;
2667               case Instruction::MOVE_OBJECT_16:
2668                 if (move_inst->VRegA_32x() == instance_of_inst->VRegB_22c()) {
2669                   update_line->SetRegisterType<LockOp::kKeep>(this,
2670                                                               move_inst->VRegB_32x(),
2671                                                               cast_type);
2672                 }
2673                 break;
2674               default:
2675                 break;
2676             }
2677           }
2678         }
2679       }
2680 
2681       break;
2682     }
2683     case Instruction::IF_LTZ:
2684     case Instruction::IF_GEZ:
2685     case Instruction::IF_GTZ:
2686     case Instruction::IF_LEZ: {
2687       const RegType& reg_type = work_line_->GetRegisterType(this, inst->VRegA_21t());
2688       if (!reg_type.IsIntegralTypes()) {
2689         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "type " << reg_type
2690                                           << " unexpected as arg to if-ltz/if-gez/if-gtz/if-lez";
2691       }
2692       break;
2693     }
2694     case Instruction::AGET_BOOLEAN:
2695       VerifyAGet(inst, reg_types_.Boolean(), true);
2696       break;
2697     case Instruction::AGET_BYTE:
2698       VerifyAGet(inst, reg_types_.Byte(), true);
2699       break;
2700     case Instruction::AGET_CHAR:
2701       VerifyAGet(inst, reg_types_.Char(), true);
2702       break;
2703     case Instruction::AGET_SHORT:
2704       VerifyAGet(inst, reg_types_.Short(), true);
2705       break;
2706     case Instruction::AGET:
2707       VerifyAGet(inst, reg_types_.Integer(), true);
2708       break;
2709     case Instruction::AGET_WIDE:
2710       VerifyAGet(inst, reg_types_.LongLo(), true);
2711       break;
2712     case Instruction::AGET_OBJECT:
2713       VerifyAGet(inst, reg_types_.JavaLangObject(false), false);
2714       break;
2715 
2716     case Instruction::APUT_BOOLEAN:
2717       VerifyAPut(inst, reg_types_.Boolean(), true);
2718       break;
2719     case Instruction::APUT_BYTE:
2720       VerifyAPut(inst, reg_types_.Byte(), true);
2721       break;
2722     case Instruction::APUT_CHAR:
2723       VerifyAPut(inst, reg_types_.Char(), true);
2724       break;
2725     case Instruction::APUT_SHORT:
2726       VerifyAPut(inst, reg_types_.Short(), true);
2727       break;
2728     case Instruction::APUT:
2729       VerifyAPut(inst, reg_types_.Integer(), true);
2730       break;
2731     case Instruction::APUT_WIDE:
2732       VerifyAPut(inst, reg_types_.LongLo(), true);
2733       break;
2734     case Instruction::APUT_OBJECT:
2735       VerifyAPut(inst, reg_types_.JavaLangObject(false), false);
2736       break;
2737 
2738     case Instruction::IGET_BOOLEAN:
2739       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Boolean(), true, false);
2740       break;
2741     case Instruction::IGET_BYTE:
2742       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Byte(), true, false);
2743       break;
2744     case Instruction::IGET_CHAR:
2745       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Char(), true, false);
2746       break;
2747     case Instruction::IGET_SHORT:
2748       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Short(), true, false);
2749       break;
2750     case Instruction::IGET:
2751       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Integer(), true, false);
2752       break;
2753     case Instruction::IGET_WIDE:
2754       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.LongLo(), true, false);
2755       break;
2756     case Instruction::IGET_OBJECT:
2757       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.JavaLangObject(false), false,
2758                                                     false);
2759       break;
2760 
2761     case Instruction::IPUT_BOOLEAN:
2762       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Boolean(), true, false);
2763       break;
2764     case Instruction::IPUT_BYTE:
2765       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Byte(), true, false);
2766       break;
2767     case Instruction::IPUT_CHAR:
2768       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Char(), true, false);
2769       break;
2770     case Instruction::IPUT_SHORT:
2771       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Short(), true, false);
2772       break;
2773     case Instruction::IPUT:
2774       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Integer(), true, false);
2775       break;
2776     case Instruction::IPUT_WIDE:
2777       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.LongLo(), true, false);
2778       break;
2779     case Instruction::IPUT_OBJECT:
2780       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.JavaLangObject(false), false,
2781                                                     false);
2782       break;
2783 
2784     case Instruction::SGET_BOOLEAN:
2785       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Boolean(), true, true);
2786       break;
2787     case Instruction::SGET_BYTE:
2788       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Byte(), true, true);
2789       break;
2790     case Instruction::SGET_CHAR:
2791       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Char(), true, true);
2792       break;
2793     case Instruction::SGET_SHORT:
2794       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Short(), true, true);
2795       break;
2796     case Instruction::SGET:
2797       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Integer(), true, true);
2798       break;
2799     case Instruction::SGET_WIDE:
2800       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.LongLo(), true, true);
2801       break;
2802     case Instruction::SGET_OBJECT:
2803       VerifyISFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.JavaLangObject(false), false,
2804                                                     true);
2805       break;
2806 
2807     case Instruction::SPUT_BOOLEAN:
2808       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Boolean(), true, true);
2809       break;
2810     case Instruction::SPUT_BYTE:
2811       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Byte(), true, true);
2812       break;
2813     case Instruction::SPUT_CHAR:
2814       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Char(), true, true);
2815       break;
2816     case Instruction::SPUT_SHORT:
2817       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Short(), true, true);
2818       break;
2819     case Instruction::SPUT:
2820       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Integer(), true, true);
2821       break;
2822     case Instruction::SPUT_WIDE:
2823       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.LongLo(), true, true);
2824       break;
2825     case Instruction::SPUT_OBJECT:
2826       VerifyISFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.JavaLangObject(false), false,
2827                                                     true);
2828       break;
2829 
2830     case Instruction::INVOKE_VIRTUAL:
2831     case Instruction::INVOKE_VIRTUAL_RANGE:
2832     case Instruction::INVOKE_SUPER:
2833     case Instruction::INVOKE_SUPER_RANGE: {
2834       bool is_range = (inst->Opcode() == Instruction::INVOKE_VIRTUAL_RANGE ||
2835                        inst->Opcode() == Instruction::INVOKE_SUPER_RANGE);
2836       bool is_super = (inst->Opcode() == Instruction::INVOKE_SUPER ||
2837                        inst->Opcode() == Instruction::INVOKE_SUPER_RANGE);
2838       MethodType type = is_super ? METHOD_SUPER : METHOD_VIRTUAL;
2839       ArtMethod* called_method = VerifyInvocationArgs(inst, type, is_range);
2840       const RegType* return_type = nullptr;
2841       if (called_method != nullptr) {
2842         size_t pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize();
2843         mirror::Class* return_type_class = called_method->GetReturnType(can_load_classes_,
2844                                                                         pointer_size);
2845         if (return_type_class != nullptr) {
2846           return_type = &FromClass(called_method->GetReturnTypeDescriptor(),
2847                                    return_type_class,
2848                                    return_type_class->CannotBeAssignedFromOtherTypes());
2849         } else {
2850           DCHECK(!can_load_classes_ || self_->IsExceptionPending());
2851           self_->ClearException();
2852         }
2853       }
2854       if (return_type == nullptr) {
2855         uint32_t method_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
2856         const DexFile::MethodId& method_id = dex_file_->GetMethodId(method_idx);
2857         uint32_t return_type_idx = dex_file_->GetProtoId(method_id.proto_idx_).return_type_idx_;
2858         const char* descriptor = dex_file_->StringByTypeIdx(return_type_idx);
2859         return_type = &reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
2860       }
2861       if (!return_type->IsLowHalf()) {
2862         work_line_->SetResultRegisterType(this, *return_type);
2863       } else {
2864         work_line_->SetResultRegisterTypeWide(*return_type, return_type->HighHalf(&reg_types_));
2865       }
2866       just_set_result = true;
2867       break;
2868     }
2869     case Instruction::INVOKE_DIRECT:
2870     case Instruction::INVOKE_DIRECT_RANGE: {
2871       bool is_range = (inst->Opcode() == Instruction::INVOKE_DIRECT_RANGE);
2872       ArtMethod* called_method = VerifyInvocationArgs(inst, METHOD_DIRECT, is_range);
2873       const char* return_type_descriptor;
2874       bool is_constructor;
2875       const RegType* return_type = nullptr;
2876       if (called_method == nullptr) {
2877         uint32_t method_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
2878         const DexFile::MethodId& method_id = dex_file_->GetMethodId(method_idx);
2879         is_constructor = strcmp("<init>", dex_file_->StringDataByIdx(method_id.name_idx_)) == 0;
2880         uint32_t return_type_idx = dex_file_->GetProtoId(method_id.proto_idx_).return_type_idx_;
2881         return_type_descriptor =  dex_file_->StringByTypeIdx(return_type_idx);
2882       } else {
2883         is_constructor = called_method->IsConstructor();
2884         return_type_descriptor = called_method->GetReturnTypeDescriptor();
2885         size_t pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize();
2886         mirror::Class* return_type_class = called_method->GetReturnType(can_load_classes_,
2887                                                                         pointer_size);
2888         if (return_type_class != nullptr) {
2889           return_type = &FromClass(return_type_descriptor,
2890                                    return_type_class,
2891                                    return_type_class->CannotBeAssignedFromOtherTypes());
2892         } else {
2893           DCHECK(!can_load_classes_ || self_->IsExceptionPending());
2894           self_->ClearException();
2895         }
2896       }
2897       if (is_constructor) {
2898         /*
2899          * Some additional checks when calling a constructor. We know from the invocation arg check
2900          * that the "this" argument is an instance of called_method->klass. Now we further restrict
2901          * that to require that called_method->klass is the same as this->klass or this->super,
2902          * allowing the latter only if the "this" argument is the same as the "this" argument to
2903          * this method (which implies that we're in a constructor ourselves).
2904          */
2905         const RegType& this_type = work_line_->GetInvocationThis(this, inst, is_range);
2906         if (this_type.IsConflict())  // failure.
2907           break;
2908 
2909         /* no null refs allowed (?) */
2910         if (this_type.IsZero()) {
2911           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unable to initialize null ref";
2912           break;
2913         }
2914 
2915         /* must be in same class or in superclass */
2916         // const RegType& this_super_klass = this_type.GetSuperClass(&reg_types_);
2917         // TODO: re-enable constructor type verification
2918         // if (this_super_klass.IsConflict()) {
2919           // Unknown super class, fail so we re-check at runtime.
2920           // Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "super class unknown for '" << this_type << "'";
2921           // break;
2922         // }
2923 
2924         /* arg must be an uninitialized reference */
2925         if (!this_type.IsUninitializedTypes()) {
2926           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Expected initialization on uninitialized reference "
2927               << this_type;
2928           break;
2929         }
2930 
2931         /*
2932          * Replace the uninitialized reference with an initialized one. We need to do this for all
2933          * registers that have the same object instance in them, not just the "this" register.
2934          */
2935         work_line_->MarkRefsAsInitialized(this, this_type);
2936       }
2937       if (return_type == nullptr) {
2938         return_type = &reg_types_.FromDescriptor(GetClassLoader(), return_type_descriptor, false);
2939       }
2940       if (!return_type->IsLowHalf()) {
2941         work_line_->SetResultRegisterType(this, *return_type);
2942       } else {
2943         work_line_->SetResultRegisterTypeWide(*return_type, return_type->HighHalf(&reg_types_));
2944       }
2945       just_set_result = true;
2946       break;
2947     }
2948     case Instruction::INVOKE_STATIC:
2949     case Instruction::INVOKE_STATIC_RANGE: {
2950         bool is_range = (inst->Opcode() == Instruction::INVOKE_STATIC_RANGE);
2951         ArtMethod* called_method = VerifyInvocationArgs(inst, METHOD_STATIC, is_range);
2952         const char* descriptor;
2953         if (called_method == nullptr) {
2954           uint32_t method_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
2955           const DexFile::MethodId& method_id = dex_file_->GetMethodId(method_idx);
2956           uint32_t return_type_idx = dex_file_->GetProtoId(method_id.proto_idx_).return_type_idx_;
2957           descriptor = dex_file_->StringByTypeIdx(return_type_idx);
2958         } else {
2959           descriptor = called_method->GetReturnTypeDescriptor();
2960         }
2961         const RegType& return_type = reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
2962         if (!return_type.IsLowHalf()) {
2963           work_line_->SetResultRegisterType(this, return_type);
2964         } else {
2965           work_line_->SetResultRegisterTypeWide(return_type, return_type.HighHalf(&reg_types_));
2966         }
2967         just_set_result = true;
2968       }
2969       break;
2970     case Instruction::INVOKE_INTERFACE:
2971     case Instruction::INVOKE_INTERFACE_RANGE: {
2972       bool is_range =  (inst->Opcode() == Instruction::INVOKE_INTERFACE_RANGE);
2973       ArtMethod* abs_method = VerifyInvocationArgs(inst, METHOD_INTERFACE, is_range);
2974       if (abs_method != nullptr) {
2975         mirror::Class* called_interface = abs_method->GetDeclaringClass();
2976         if (!called_interface->IsInterface() && !called_interface->IsObjectClass()) {
2977           Fail(VERIFY_ERROR_CLASS_CHANGE) << "expected interface class in invoke-interface '"
2978               << PrettyMethod(abs_method) << "'";
2979           break;
2980         }
2981       }
2982       /* Get the type of the "this" arg, which should either be a sub-interface of called
2983        * interface or Object (see comments in RegType::JoinClass).
2984        */
2985       const RegType& this_type = work_line_->GetInvocationThis(this, inst, is_range);
2986       if (this_type.IsZero()) {
2987         /* null pointer always passes (and always fails at runtime) */
2988       } else {
2989         if (this_type.IsUninitializedTypes()) {
2990           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "interface call on uninitialized object "
2991               << this_type;
2992           break;
2993         }
2994         // In the past we have tried to assert that "called_interface" is assignable
2995         // from "this_type.GetClass()", however, as we do an imprecise Join
2996         // (RegType::JoinClass) we don't have full information on what interfaces are
2997         // implemented by "this_type". For example, two classes may implement the same
2998         // interfaces and have a common parent that doesn't implement the interface. The
2999         // join will set "this_type" to the parent class and a test that this implements
3000         // the interface will incorrectly fail.
3001       }
3002       /*
3003        * We don't have an object instance, so we can't find the concrete method. However, all of
3004        * the type information is in the abstract method, so we're good.
3005        */
3006       const char* descriptor;
3007       if (abs_method == nullptr) {
3008         uint32_t method_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
3009         const DexFile::MethodId& method_id = dex_file_->GetMethodId(method_idx);
3010         uint32_t return_type_idx = dex_file_->GetProtoId(method_id.proto_idx_).return_type_idx_;
3011         descriptor = dex_file_->StringByTypeIdx(return_type_idx);
3012       } else {
3013         descriptor = abs_method->GetReturnTypeDescriptor();
3014       }
3015       const RegType& return_type = reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
3016       if (!return_type.IsLowHalf()) {
3017         work_line_->SetResultRegisterType(this, return_type);
3018       } else {
3019         work_line_->SetResultRegisterTypeWide(return_type, return_type.HighHalf(&reg_types_));
3020       }
3021       just_set_result = true;
3022       break;
3023     }
3024     case Instruction::NEG_INT:
3025     case Instruction::NOT_INT:
3026       work_line_->CheckUnaryOp(this, inst, reg_types_.Integer(), reg_types_.Integer());
3027       break;
3028     case Instruction::NEG_LONG:
3029     case Instruction::NOT_LONG:
3030       work_line_->CheckUnaryOpWide(this, inst, reg_types_.LongLo(), reg_types_.LongHi(),
3031                                    reg_types_.LongLo(), reg_types_.LongHi());
3032       break;
3033     case Instruction::NEG_FLOAT:
3034       work_line_->CheckUnaryOp(this, inst, reg_types_.Float(), reg_types_.Float());
3035       break;
3036     case Instruction::NEG_DOUBLE:
3037       work_line_->CheckUnaryOpWide(this, inst, reg_types_.DoubleLo(), reg_types_.DoubleHi(),
3038                                    reg_types_.DoubleLo(), reg_types_.DoubleHi());
3039       break;
3040     case Instruction::INT_TO_LONG:
3041       work_line_->CheckUnaryOpToWide(this, inst, reg_types_.LongLo(), reg_types_.LongHi(),
3042                                      reg_types_.Integer());
3043       break;
3044     case Instruction::INT_TO_FLOAT:
3045       work_line_->CheckUnaryOp(this, inst, reg_types_.Float(), reg_types_.Integer());
3046       break;
3047     case Instruction::INT_TO_DOUBLE:
3048       work_line_->CheckUnaryOpToWide(this, inst, reg_types_.DoubleLo(), reg_types_.DoubleHi(),
3049                                      reg_types_.Integer());
3050       break;
3051     case Instruction::LONG_TO_INT:
3052       work_line_->CheckUnaryOpFromWide(this, inst, reg_types_.Integer(),
3053                                        reg_types_.LongLo(), reg_types_.LongHi());
3054       break;
3055     case Instruction::LONG_TO_FLOAT:
3056       work_line_->CheckUnaryOpFromWide(this, inst, reg_types_.Float(),
3057                                        reg_types_.LongLo(), reg_types_.LongHi());
3058       break;
3059     case Instruction::LONG_TO_DOUBLE:
3060       work_line_->CheckUnaryOpWide(this, inst, reg_types_.DoubleLo(), reg_types_.DoubleHi(),
3061                                    reg_types_.LongLo(), reg_types_.LongHi());
3062       break;
3063     case Instruction::FLOAT_TO_INT:
3064       work_line_->CheckUnaryOp(this, inst, reg_types_.Integer(), reg_types_.Float());
3065       break;
3066     case Instruction::FLOAT_TO_LONG:
3067       work_line_->CheckUnaryOpToWide(this, inst, reg_types_.LongLo(), reg_types_.LongHi(),
3068                                      reg_types_.Float());
3069       break;
3070     case Instruction::FLOAT_TO_DOUBLE:
3071       work_line_->CheckUnaryOpToWide(this, inst, reg_types_.DoubleLo(), reg_types_.DoubleHi(),
3072                                      reg_types_.Float());
3073       break;
3074     case Instruction::DOUBLE_TO_INT:
3075       work_line_->CheckUnaryOpFromWide(this, inst, reg_types_.Integer(),
3076                                        reg_types_.DoubleLo(), reg_types_.DoubleHi());
3077       break;
3078     case Instruction::DOUBLE_TO_LONG:
3079       work_line_->CheckUnaryOpWide(this, inst, reg_types_.LongLo(), reg_types_.LongHi(),
3080                                    reg_types_.DoubleLo(), reg_types_.DoubleHi());
3081       break;
3082     case Instruction::DOUBLE_TO_FLOAT:
3083       work_line_->CheckUnaryOpFromWide(this, inst, reg_types_.Float(),
3084                                        reg_types_.DoubleLo(), reg_types_.DoubleHi());
3085       break;
3086     case Instruction::INT_TO_BYTE:
3087       work_line_->CheckUnaryOp(this, inst, reg_types_.Byte(), reg_types_.Integer());
3088       break;
3089     case Instruction::INT_TO_CHAR:
3090       work_line_->CheckUnaryOp(this, inst, reg_types_.Char(), reg_types_.Integer());
3091       break;
3092     case Instruction::INT_TO_SHORT:
3093       work_line_->CheckUnaryOp(this, inst, reg_types_.Short(), reg_types_.Integer());
3094       break;
3095 
3096     case Instruction::ADD_INT:
3097     case Instruction::SUB_INT:
3098     case Instruction::MUL_INT:
3099     case Instruction::REM_INT:
3100     case Instruction::DIV_INT:
3101     case Instruction::SHL_INT:
3102     case Instruction::SHR_INT:
3103     case Instruction::USHR_INT:
3104       work_line_->CheckBinaryOp(this, inst, reg_types_.Integer(), reg_types_.Integer(),
3105                                 reg_types_.Integer(), false);
3106       break;
3107     case Instruction::AND_INT:
3108     case Instruction::OR_INT:
3109     case Instruction::XOR_INT:
3110       work_line_->CheckBinaryOp(this, inst, reg_types_.Integer(), reg_types_.Integer(),
3111                                 reg_types_.Integer(), true);
3112       break;
3113     case Instruction::ADD_LONG:
3114     case Instruction::SUB_LONG:
3115     case Instruction::MUL_LONG:
3116     case Instruction::DIV_LONG:
3117     case Instruction::REM_LONG:
3118     case Instruction::AND_LONG:
3119     case Instruction::OR_LONG:
3120     case Instruction::XOR_LONG:
3121       work_line_->CheckBinaryOpWide(this, inst, reg_types_.LongLo(), reg_types_.LongHi(),
3122                                     reg_types_.LongLo(), reg_types_.LongHi(),
3123                                     reg_types_.LongLo(), reg_types_.LongHi());
3124       break;
3125     case Instruction::SHL_LONG:
3126     case Instruction::SHR_LONG:
3127     case Instruction::USHR_LONG:
3128       /* shift distance is Int, making these different from other binary operations */
3129       work_line_->CheckBinaryOpWideShift(this, inst, reg_types_.LongLo(), reg_types_.LongHi(),
3130                                          reg_types_.Integer());
3131       break;
3132     case Instruction::ADD_FLOAT:
3133     case Instruction::SUB_FLOAT:
3134     case Instruction::MUL_FLOAT:
3135     case Instruction::DIV_FLOAT:
3136     case Instruction::REM_FLOAT:
3137       work_line_->CheckBinaryOp(this, inst, reg_types_.Float(), reg_types_.Float(),
3138                                 reg_types_.Float(), false);
3139       break;
3140     case Instruction::ADD_DOUBLE:
3141     case Instruction::SUB_DOUBLE:
3142     case Instruction::MUL_DOUBLE:
3143     case Instruction::DIV_DOUBLE:
3144     case Instruction::REM_DOUBLE:
3145       work_line_->CheckBinaryOpWide(this, inst, reg_types_.DoubleLo(), reg_types_.DoubleHi(),
3146                                     reg_types_.DoubleLo(), reg_types_.DoubleHi(),
3147                                     reg_types_.DoubleLo(), reg_types_.DoubleHi());
3148       break;
3149     case Instruction::ADD_INT_2ADDR:
3150     case Instruction::SUB_INT_2ADDR:
3151     case Instruction::MUL_INT_2ADDR:
3152     case Instruction::REM_INT_2ADDR:
3153     case Instruction::SHL_INT_2ADDR:
3154     case Instruction::SHR_INT_2ADDR:
3155     case Instruction::USHR_INT_2ADDR:
3156       work_line_->CheckBinaryOp2addr(this, inst, reg_types_.Integer(), reg_types_.Integer(),
3157                                      reg_types_.Integer(), false);
3158       break;
3159     case Instruction::AND_INT_2ADDR:
3160     case Instruction::OR_INT_2ADDR:
3161     case Instruction::XOR_INT_2ADDR:
3162       work_line_->CheckBinaryOp2addr(this, inst, reg_types_.Integer(), reg_types_.Integer(),
3163                                      reg_types_.Integer(), true);
3164       break;
3165     case Instruction::DIV_INT_2ADDR:
3166       work_line_->CheckBinaryOp2addr(this, inst, reg_types_.Integer(), reg_types_.Integer(),
3167                                      reg_types_.Integer(), false);
3168       break;
3169     case Instruction::ADD_LONG_2ADDR:
3170     case Instruction::SUB_LONG_2ADDR:
3171     case Instruction::MUL_LONG_2ADDR:
3172     case Instruction::DIV_LONG_2ADDR:
3173     case Instruction::REM_LONG_2ADDR:
3174     case Instruction::AND_LONG_2ADDR:
3175     case Instruction::OR_LONG_2ADDR:
3176     case Instruction::XOR_LONG_2ADDR:
3177       work_line_->CheckBinaryOp2addrWide(this, inst, reg_types_.LongLo(), reg_types_.LongHi(),
3178                                          reg_types_.LongLo(), reg_types_.LongHi(),
3179                                          reg_types_.LongLo(), reg_types_.LongHi());
3180       break;
3181     case Instruction::SHL_LONG_2ADDR:
3182     case Instruction::SHR_LONG_2ADDR:
3183     case Instruction::USHR_LONG_2ADDR:
3184       work_line_->CheckBinaryOp2addrWideShift(this, inst, reg_types_.LongLo(), reg_types_.LongHi(),
3185                                               reg_types_.Integer());
3186       break;
3187     case Instruction::ADD_FLOAT_2ADDR:
3188     case Instruction::SUB_FLOAT_2ADDR:
3189     case Instruction::MUL_FLOAT_2ADDR:
3190     case Instruction::DIV_FLOAT_2ADDR:
3191     case Instruction::REM_FLOAT_2ADDR:
3192       work_line_->CheckBinaryOp2addr(this, inst, reg_types_.Float(), reg_types_.Float(),
3193                                      reg_types_.Float(), false);
3194       break;
3195     case Instruction::ADD_DOUBLE_2ADDR:
3196     case Instruction::SUB_DOUBLE_2ADDR:
3197     case Instruction::MUL_DOUBLE_2ADDR:
3198     case Instruction::DIV_DOUBLE_2ADDR:
3199     case Instruction::REM_DOUBLE_2ADDR:
3200       work_line_->CheckBinaryOp2addrWide(this, inst, reg_types_.DoubleLo(), reg_types_.DoubleHi(),
3201                                          reg_types_.DoubleLo(),  reg_types_.DoubleHi(),
3202                                          reg_types_.DoubleLo(), reg_types_.DoubleHi());
3203       break;
3204     case Instruction::ADD_INT_LIT16:
3205     case Instruction::RSUB_INT_LIT16:
3206     case Instruction::MUL_INT_LIT16:
3207     case Instruction::DIV_INT_LIT16:
3208     case Instruction::REM_INT_LIT16:
3209       work_line_->CheckLiteralOp(this, inst, reg_types_.Integer(), reg_types_.Integer(), false,
3210                                  true);
3211       break;
3212     case Instruction::AND_INT_LIT16:
3213     case Instruction::OR_INT_LIT16:
3214     case Instruction::XOR_INT_LIT16:
3215       work_line_->CheckLiteralOp(this, inst, reg_types_.Integer(), reg_types_.Integer(), true,
3216                                  true);
3217       break;
3218     case Instruction::ADD_INT_LIT8:
3219     case Instruction::RSUB_INT_LIT8:
3220     case Instruction::MUL_INT_LIT8:
3221     case Instruction::DIV_INT_LIT8:
3222     case Instruction::REM_INT_LIT8:
3223     case Instruction::SHL_INT_LIT8:
3224     case Instruction::SHR_INT_LIT8:
3225     case Instruction::USHR_INT_LIT8:
3226       work_line_->CheckLiteralOp(this, inst, reg_types_.Integer(), reg_types_.Integer(), false,
3227                                  false);
3228       break;
3229     case Instruction::AND_INT_LIT8:
3230     case Instruction::OR_INT_LIT8:
3231     case Instruction::XOR_INT_LIT8:
3232       work_line_->CheckLiteralOp(this, inst, reg_types_.Integer(), reg_types_.Integer(), true,
3233                                  false);
3234       break;
3235 
3236     // Special instructions.
3237     case Instruction::RETURN_VOID_NO_BARRIER:
3238       if (IsConstructor() && !IsStatic()) {
3239         auto& declaring_class = GetDeclaringClass();
3240         if (declaring_class.IsUnresolvedReference()) {
3241           // We must iterate over the fields, even if we cannot use mirror classes to do so. Do it
3242           // manually over the underlying dex file.
3243           uint32_t first_index = GetFirstFinalInstanceFieldIndex(*dex_file_,
3244               dex_file_->GetMethodId(dex_method_idx_).class_idx_);
3245           if (first_index != DexFile::kDexNoIndex) {
3246             Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "return-void-no-barrier not expected for field "
3247                               << first_index;
3248           }
3249           break;
3250         }
3251         auto* klass = declaring_class.GetClass();
3252         for (uint32_t i = 0, num_fields = klass->NumInstanceFields(); i < num_fields; ++i) {
3253           if (klass->GetInstanceField(i)->IsFinal()) {
3254             Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "return-void-no-barrier not expected for "
3255                 << PrettyField(klass->GetInstanceField(i));
3256             break;
3257           }
3258         }
3259       }
3260       // Handle this like a RETURN_VOID now. Code is duplicated to separate standard from
3261       // quickened opcodes (otherwise this could be a fall-through).
3262       if (!IsConstructor()) {
3263         if (!GetMethodReturnType().IsConflict()) {
3264           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "return-void not expected";
3265         }
3266       }
3267       break;
3268     // Note: the following instructions encode offsets derived from class linking.
3269     // As such they use Class*/Field*/AbstractMethod* as these offsets only have
3270     // meaning if the class linking and resolution were successful.
3271     case Instruction::IGET_QUICK:
3272       VerifyQuickFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Integer(), true);
3273       break;
3274     case Instruction::IGET_WIDE_QUICK:
3275       VerifyQuickFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.LongLo(), true);
3276       break;
3277     case Instruction::IGET_OBJECT_QUICK:
3278       VerifyQuickFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.JavaLangObject(false), false);
3279       break;
3280     case Instruction::IGET_BOOLEAN_QUICK:
3281       VerifyQuickFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Boolean(), true);
3282       break;
3283     case Instruction::IGET_BYTE_QUICK:
3284       VerifyQuickFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Byte(), true);
3285       break;
3286     case Instruction::IGET_CHAR_QUICK:
3287       VerifyQuickFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Char(), true);
3288       break;
3289     case Instruction::IGET_SHORT_QUICK:
3290       VerifyQuickFieldAccess<FieldAccessType::kAccGet>(inst, reg_types_.Short(), true);
3291       break;
3292     case Instruction::IPUT_QUICK:
3293       VerifyQuickFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Integer(), true);
3294       break;
3295     case Instruction::IPUT_BOOLEAN_QUICK:
3296       VerifyQuickFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Boolean(), true);
3297       break;
3298     case Instruction::IPUT_BYTE_QUICK:
3299       VerifyQuickFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Byte(), true);
3300       break;
3301     case Instruction::IPUT_CHAR_QUICK:
3302       VerifyQuickFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Char(), true);
3303       break;
3304     case Instruction::IPUT_SHORT_QUICK:
3305       VerifyQuickFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.Short(), true);
3306       break;
3307     case Instruction::IPUT_WIDE_QUICK:
3308       VerifyQuickFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.LongLo(), true);
3309       break;
3310     case Instruction::IPUT_OBJECT_QUICK:
3311       VerifyQuickFieldAccess<FieldAccessType::kAccPut>(inst, reg_types_.JavaLangObject(false), false);
3312       break;
3313     case Instruction::INVOKE_VIRTUAL_QUICK:
3314     case Instruction::INVOKE_VIRTUAL_RANGE_QUICK: {
3315       bool is_range = (inst->Opcode() == Instruction::INVOKE_VIRTUAL_RANGE_QUICK);
3316       ArtMethod* called_method = VerifyInvokeVirtualQuickArgs(inst, is_range);
3317       if (called_method != nullptr) {
3318         const char* descriptor = called_method->GetReturnTypeDescriptor();
3319         const RegType& return_type = reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
3320         if (!return_type.IsLowHalf()) {
3321           work_line_->SetResultRegisterType(this, return_type);
3322         } else {
3323           work_line_->SetResultRegisterTypeWide(return_type, return_type.HighHalf(&reg_types_));
3324         }
3325         just_set_result = true;
3326       }
3327       break;
3328     }
3329     case Instruction::INVOKE_LAMBDA: {
3330       // Don't bother verifying, instead the interpreter will take the slow path with access checks.
3331       // If the code would've normally hard-failed, then the interpreter will throw the
3332       // appropriate verification errors at runtime.
3333       Fail(VERIFY_ERROR_FORCE_INTERPRETER);  // TODO(iam): implement invoke-lambda verification
3334       break;
3335     }
3336     case Instruction::CAPTURE_VARIABLE: {
3337       // Don't bother verifying, instead the interpreter will take the slow path with access checks.
3338       // If the code would've normally hard-failed, then the interpreter will throw the
3339       // appropriate verification errors at runtime.
3340       Fail(VERIFY_ERROR_FORCE_INTERPRETER);  // TODO(iam): implement capture-variable verification
3341       break;
3342     }
3343     case Instruction::CREATE_LAMBDA: {
3344       // Don't bother verifying, instead the interpreter will take the slow path with access checks.
3345       // If the code would've normally hard-failed, then the interpreter will throw the
3346       // appropriate verification errors at runtime.
3347       Fail(VERIFY_ERROR_FORCE_INTERPRETER);  // TODO(iam): implement create-lambda verification
3348       break;
3349     }
3350     case Instruction::LIBERATE_VARIABLE: {
3351       // Don't bother verifying, instead the interpreter will take the slow path with access checks.
3352       // If the code would've normally hard-failed, then the interpreter will throw the
3353       // appropriate verification errors at runtime.
3354       Fail(VERIFY_ERROR_FORCE_INTERPRETER);  // TODO(iam): implement liberate-variable verification
3355       break;
3356     }
3357 
3358     case Instruction::UNUSED_F4: {
3359       DCHECK(false);  // TODO(iam): Implement opcodes for lambdas
3360       // Conservatively fail verification on release builds.
3361       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Unexpected opcode " << inst->DumpString(dex_file_);
3362       break;
3363     }
3364 
3365     case Instruction::BOX_LAMBDA: {
3366       // Don't bother verifying, instead the interpreter will take the slow path with access checks.
3367       // If the code would've normally hard-failed, then the interpreter will throw the
3368       // appropriate verification errors at runtime.
3369       Fail(VERIFY_ERROR_FORCE_INTERPRETER);  // TODO(iam): implement box-lambda verification
3370 
3371       // Partial verification. Sets the resulting type to always be an object, which
3372       // is good enough for some other verification to occur without hard-failing.
3373       const uint32_t vreg_target_object = inst->VRegA_22x();  // box-lambda vA, vB
3374       const RegType& reg_type = reg_types_.JavaLangObject(need_precise_constants_);
3375       work_line_->SetRegisterType<LockOp::kClear>(this, vreg_target_object, reg_type);
3376       break;
3377     }
3378 
3379      case Instruction::UNBOX_LAMBDA: {
3380       // Don't bother verifying, instead the interpreter will take the slow path with access checks.
3381       // If the code would've normally hard-failed, then the interpreter will throw the
3382       // appropriate verification errors at runtime.
3383       Fail(VERIFY_ERROR_FORCE_INTERPRETER);  // TODO(iam): implement unbox-lambda verification
3384       break;
3385     }
3386 
3387     /* These should never appear during verification. */
3388     case Instruction::UNUSED_3E ... Instruction::UNUSED_43:
3389     case Instruction::UNUSED_FA ... Instruction::UNUSED_FF:
3390     case Instruction::UNUSED_79:
3391     case Instruction::UNUSED_7A:
3392       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Unexpected opcode " << inst->DumpString(dex_file_);
3393       break;
3394 
3395     /*
3396      * DO NOT add a "default" clause here. Without it the compiler will
3397      * complain if an instruction is missing (which is desirable).
3398      */
3399   }  // end - switch (dec_insn.opcode)
3400 
3401   if (have_pending_hard_failure_) {
3402     if (Runtime::Current()->IsAotCompiler()) {
3403       /* When AOT compiling, check that the last failure is a hard failure */
3404       if (failures_[failures_.size() - 1] != VERIFY_ERROR_BAD_CLASS_HARD) {
3405         LOG(ERROR) << "Pending failures:";
3406         for (auto& error : failures_) {
3407           LOG(ERROR) << error;
3408         }
3409         for (auto& error_msg : failure_messages_) {
3410           LOG(ERROR) << error_msg->str();
3411         }
3412         LOG(FATAL) << "Pending hard failure, but last failure not hard.";
3413       }
3414     }
3415     /* immediate failure, reject class */
3416     info_messages_ << "Rejecting opcode " << inst->DumpString(dex_file_);
3417     return false;
3418   } else if (have_pending_runtime_throw_failure_) {
3419     /* checking interpreter will throw, mark following code as unreachable */
3420     opcode_flags = Instruction::kThrow;
3421     // Note: the flag must be reset as it is only global to decouple Fail and is semantically per
3422     //       instruction. However, RETURN checking may throw LOCKING errors, so we clear at the
3423     //       very end.
3424   }
3425   /*
3426    * If we didn't just set the result register, clear it out. This ensures that you can only use
3427    * "move-result" immediately after the result is set. (We could check this statically, but it's
3428    * not expensive and it makes our debugging output cleaner.)
3429    */
3430   if (!just_set_result) {
3431     work_line_->SetResultTypeToUnknown(this);
3432   }
3433 
3434 
3435 
3436   /*
3437    * Handle "branch". Tag the branch target.
3438    *
3439    * NOTE: instructions like Instruction::EQZ provide information about the
3440    * state of the register when the branch is taken or not taken. For example,
3441    * somebody could get a reference field, check it for zero, and if the
3442    * branch is taken immediately store that register in a boolean field
3443    * since the value is known to be zero. We do not currently account for
3444    * that, and will reject the code.
3445    *
3446    * TODO: avoid re-fetching the branch target
3447    */
3448   if ((opcode_flags & Instruction::kBranch) != 0) {
3449     bool isConditional, selfOkay;
3450     if (!GetBranchOffset(work_insn_idx_, &branch_target, &isConditional, &selfOkay)) {
3451       /* should never happen after static verification */
3452       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "bad branch";
3453       return false;
3454     }
3455     DCHECK_EQ(isConditional, (opcode_flags & Instruction::kContinue) != 0);
3456     if (!CheckNotMoveExceptionOrMoveResult(code_item_->insns_, work_insn_idx_ + branch_target)) {
3457       return false;
3458     }
3459     /* update branch target, set "changed" if appropriate */
3460     if (nullptr != branch_line) {
3461       if (!UpdateRegisters(work_insn_idx_ + branch_target, branch_line.get(), false)) {
3462         return false;
3463       }
3464     } else {
3465       if (!UpdateRegisters(work_insn_idx_ + branch_target, work_line_.get(), false)) {
3466         return false;
3467       }
3468     }
3469   }
3470 
3471   /*
3472    * Handle "switch". Tag all possible branch targets.
3473    *
3474    * We've already verified that the table is structurally sound, so we
3475    * just need to walk through and tag the targets.
3476    */
3477   if ((opcode_flags & Instruction::kSwitch) != 0) {
3478     int offset_to_switch = insns[1] | (static_cast<int32_t>(insns[2]) << 16);
3479     const uint16_t* switch_insns = insns + offset_to_switch;
3480     int switch_count = switch_insns[1];
3481     int offset_to_targets, targ;
3482 
3483     if ((*insns & 0xff) == Instruction::PACKED_SWITCH) {
3484       /* 0 = sig, 1 = count, 2/3 = first key */
3485       offset_to_targets = 4;
3486     } else {
3487       /* 0 = sig, 1 = count, 2..count * 2 = keys */
3488       DCHECK((*insns & 0xff) == Instruction::SPARSE_SWITCH);
3489       offset_to_targets = 2 + 2 * switch_count;
3490     }
3491 
3492     /* verify each switch target */
3493     for (targ = 0; targ < switch_count; targ++) {
3494       int offset;
3495       uint32_t abs_offset;
3496 
3497       /* offsets are 32-bit, and only partly endian-swapped */
3498       offset = switch_insns[offset_to_targets + targ * 2] |
3499          (static_cast<int32_t>(switch_insns[offset_to_targets + targ * 2 + 1]) << 16);
3500       abs_offset = work_insn_idx_ + offset;
3501       DCHECK_LT(abs_offset, code_item_->insns_size_in_code_units_);
3502       if (!CheckNotMoveExceptionOrMoveResult(code_item_->insns_, abs_offset)) {
3503         return false;
3504       }
3505       if (!UpdateRegisters(abs_offset, work_line_.get(), false)) {
3506         return false;
3507       }
3508     }
3509   }
3510 
3511   /*
3512    * Handle instructions that can throw and that are sitting in a "try" block. (If they're not in a
3513    * "try" block when they throw, control transfers out of the method.)
3514    */
3515   if ((opcode_flags & Instruction::kThrow) != 0 && GetInstructionFlags(work_insn_idx_).IsInTry()) {
3516     bool has_catch_all_handler = false;
3517     CatchHandlerIterator iterator(*code_item_, work_insn_idx_);
3518 
3519     // Need the linker to try and resolve the handled class to check if it's Throwable.
3520     ClassLinker* linker = Runtime::Current()->GetClassLinker();
3521 
3522     for (; iterator.HasNext(); iterator.Next()) {
3523       uint16_t handler_type_idx = iterator.GetHandlerTypeIndex();
3524       if (handler_type_idx == DexFile::kDexNoIndex16) {
3525         has_catch_all_handler = true;
3526       } else {
3527         // It is also a catch-all if it is java.lang.Throwable.
3528         mirror::Class* klass = linker->ResolveType(*dex_file_, handler_type_idx, dex_cache_,
3529                                                    class_loader_);
3530         if (klass != nullptr) {
3531           if (klass == mirror::Throwable::GetJavaLangThrowable()) {
3532             has_catch_all_handler = true;
3533           }
3534         } else {
3535           // Clear exception.
3536           DCHECK(self_->IsExceptionPending());
3537           self_->ClearException();
3538         }
3539       }
3540       /*
3541        * Merge registers into the "catch" block. We want to use the "savedRegs" rather than
3542        * "work_regs", because at runtime the exception will be thrown before the instruction
3543        * modifies any registers.
3544        */
3545       if (!UpdateRegisters(iterator.GetHandlerAddress(), saved_line_.get(), false)) {
3546         return false;
3547       }
3548     }
3549 
3550     /*
3551      * If the monitor stack depth is nonzero, there must be a "catch all" handler for this
3552      * instruction. This does apply to monitor-exit because of async exception handling.
3553      */
3554     if (work_line_->MonitorStackDepth() > 0 && !has_catch_all_handler) {
3555       /*
3556        * The state in work_line reflects the post-execution state. If the current instruction is a
3557        * monitor-enter and the monitor stack was empty, we don't need a catch-all (if it throws,
3558        * it will do so before grabbing the lock).
3559        */
3560       if (inst->Opcode() != Instruction::MONITOR_ENTER || work_line_->MonitorStackDepth() != 1) {
3561         Fail(VERIFY_ERROR_BAD_CLASS_HARD)
3562             << "expected to be within a catch-all for an instruction where a monitor is held";
3563         return false;
3564       }
3565     }
3566   }
3567 
3568   /* Handle "continue". Tag the next consecutive instruction.
3569    *  Note: Keep the code handling "continue" case below the "branch" and "switch" cases,
3570    *        because it changes work_line_ when performing peephole optimization
3571    *        and this change should not be used in those cases.
3572    */
3573   if ((opcode_flags & Instruction::kContinue) != 0) {
3574     DCHECK_EQ(Instruction::At(code_item_->insns_ + work_insn_idx_), inst);
3575     uint32_t next_insn_idx = work_insn_idx_ + inst->SizeInCodeUnits();
3576     if (next_insn_idx >= code_item_->insns_size_in_code_units_) {
3577       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Execution can walk off end of code area";
3578       return false;
3579     }
3580     // The only way to get to a move-exception instruction is to get thrown there. Make sure the
3581     // next instruction isn't one.
3582     if (!CheckNotMoveException(code_item_->insns_, next_insn_idx)) {
3583       return false;
3584     }
3585     if (nullptr != fallthrough_line) {
3586       // Make workline consistent with fallthrough computed from peephole optimization.
3587       work_line_->CopyFromLine(fallthrough_line.get());
3588     }
3589     if (GetInstructionFlags(next_insn_idx).IsReturn()) {
3590       // For returns we only care about the operand to the return, all other registers are dead.
3591       const Instruction* ret_inst = Instruction::At(code_item_->insns_ + next_insn_idx);
3592       AdjustReturnLine(this, ret_inst, work_line_.get());
3593     }
3594     RegisterLine* next_line = reg_table_.GetLine(next_insn_idx);
3595     if (next_line != nullptr) {
3596       // Merge registers into what we have for the next instruction, and set the "changed" flag if
3597       // needed. If the merge changes the state of the registers then the work line will be
3598       // updated.
3599       if (!UpdateRegisters(next_insn_idx, work_line_.get(), true)) {
3600         return false;
3601       }
3602     } else {
3603       /*
3604        * We're not recording register data for the next instruction, so we don't know what the
3605        * prior state was. We have to assume that something has changed and re-evaluate it.
3606        */
3607       GetInstructionFlags(next_insn_idx).SetChanged();
3608     }
3609   }
3610 
3611   /* If we're returning from the method, make sure monitor stack is empty. */
3612   if ((opcode_flags & Instruction::kReturn) != 0) {
3613     work_line_->VerifyMonitorStackEmpty(this);
3614   }
3615 
3616   /*
3617    * Update start_guess. Advance to the next instruction of that's
3618    * possible, otherwise use the branch target if one was found. If
3619    * neither of those exists we're in a return or throw; leave start_guess
3620    * alone and let the caller sort it out.
3621    */
3622   if ((opcode_flags & Instruction::kContinue) != 0) {
3623     DCHECK_EQ(Instruction::At(code_item_->insns_ + work_insn_idx_), inst);
3624     *start_guess = work_insn_idx_ + inst->SizeInCodeUnits();
3625   } else if ((opcode_flags & Instruction::kBranch) != 0) {
3626     /* we're still okay if branch_target is zero */
3627     *start_guess = work_insn_idx_ + branch_target;
3628   }
3629 
3630   DCHECK_LT(*start_guess, code_item_->insns_size_in_code_units_);
3631   DCHECK(GetInstructionFlags(*start_guess).IsOpcode());
3632 
3633   if (have_pending_runtime_throw_failure_) {
3634     have_any_pending_runtime_throw_failure_ = true;
3635     // Reset the pending_runtime_throw flag now.
3636     have_pending_runtime_throw_failure_ = false;
3637   }
3638 
3639   return true;
3640 }  // NOLINT(readability/fn_size)
3641 
UninstantiableError(const char * descriptor)3642 void MethodVerifier::UninstantiableError(const char* descriptor) {
3643   Fail(VerifyError::VERIFY_ERROR_NO_CLASS) << "Could not create precise reference for "
3644                                            << "non-instantiable klass " << descriptor;
3645 }
3646 
IsInstantiableOrPrimitive(mirror::Class * klass)3647 inline bool MethodVerifier::IsInstantiableOrPrimitive(mirror::Class* klass) {
3648   return klass->IsInstantiable() || klass->IsPrimitive();
3649 }
3650 
ResolveClassAndCheckAccess(uint32_t class_idx)3651 const RegType& MethodVerifier::ResolveClassAndCheckAccess(uint32_t class_idx) {
3652   mirror::Class* klass = dex_cache_->GetResolvedType(class_idx);
3653   const RegType* result = nullptr;
3654   if (klass != nullptr) {
3655     bool precise = klass->CannotBeAssignedFromOtherTypes();
3656     if (precise && !IsInstantiableOrPrimitive(klass)) {
3657       const char* descriptor = dex_file_->StringByTypeIdx(class_idx);
3658       UninstantiableError(descriptor);
3659       precise = false;
3660     }
3661     result = reg_types_.FindClass(klass, precise);
3662     if (result == nullptr) {
3663       const char* descriptor = dex_file_->StringByTypeIdx(class_idx);
3664       result = reg_types_.InsertClass(descriptor, klass, precise);
3665     }
3666   } else {
3667     const char* descriptor = dex_file_->StringByTypeIdx(class_idx);
3668     result = &reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
3669   }
3670   DCHECK(result != nullptr);
3671   if (result->IsConflict()) {
3672     const char* descriptor = dex_file_->StringByTypeIdx(class_idx);
3673     Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "accessing broken descriptor '" << descriptor
3674         << "' in " << GetDeclaringClass();
3675     return *result;
3676   }
3677   if (klass == nullptr && !result->IsUnresolvedTypes()) {
3678     dex_cache_->SetResolvedType(class_idx, result->GetClass());
3679   }
3680   // Check if access is allowed. Unresolved types use xxxWithAccessCheck to
3681   // check at runtime if access is allowed and so pass here. If result is
3682   // primitive, skip the access check.
3683   if (result->IsNonZeroReferenceTypes() && !result->IsUnresolvedTypes()) {
3684     const RegType& referrer = GetDeclaringClass();
3685     if (!referrer.IsUnresolvedTypes() && !referrer.CanAccess(*result)) {
3686       Fail(VERIFY_ERROR_ACCESS_CLASS) << "illegal class access: '"
3687                                       << referrer << "' -> '" << result << "'";
3688     }
3689   }
3690   return *result;
3691 }
3692 
GetCaughtExceptionType()3693 const RegType& MethodVerifier::GetCaughtExceptionType() {
3694   const RegType* common_super = nullptr;
3695   if (code_item_->tries_size_ != 0) {
3696     const uint8_t* handlers_ptr = DexFile::GetCatchHandlerData(*code_item_, 0);
3697     uint32_t handlers_size = DecodeUnsignedLeb128(&handlers_ptr);
3698     for (uint32_t i = 0; i < handlers_size; i++) {
3699       CatchHandlerIterator iterator(handlers_ptr);
3700       for (; iterator.HasNext(); iterator.Next()) {
3701         if (iterator.GetHandlerAddress() == (uint32_t) work_insn_idx_) {
3702           if (iterator.GetHandlerTypeIndex() == DexFile::kDexNoIndex16) {
3703             common_super = &reg_types_.JavaLangThrowable(false);
3704           } else {
3705             const RegType& exception = ResolveClassAndCheckAccess(iterator.GetHandlerTypeIndex());
3706             if (!reg_types_.JavaLangThrowable(false).IsAssignableFrom(exception)) {
3707               DCHECK(!exception.IsUninitializedTypes());  // Comes from dex, shouldn't be uninit.
3708               if (exception.IsUnresolvedTypes()) {
3709                 // We don't know enough about the type. Fail here and let runtime handle it.
3710                 Fail(VERIFY_ERROR_NO_CLASS) << "unresolved exception class " << exception;
3711                 return exception;
3712               } else {
3713                 Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "unexpected non-exception class " << exception;
3714                 return reg_types_.Conflict();
3715               }
3716             } else if (common_super == nullptr) {
3717               common_super = &exception;
3718             } else if (common_super->Equals(exception)) {
3719               // odd case, but nothing to do
3720             } else {
3721               common_super = &common_super->Merge(exception, &reg_types_);
3722               if (FailOrAbort(this,
3723                               reg_types_.JavaLangThrowable(false).IsAssignableFrom(*common_super),
3724                               "java.lang.Throwable is not assignable-from common_super at ",
3725                               work_insn_idx_)) {
3726                 break;
3727               }
3728             }
3729           }
3730         }
3731       }
3732       handlers_ptr = iterator.EndDataPointer();
3733     }
3734   }
3735   if (common_super == nullptr) {
3736     /* no catch blocks, or no catches with classes we can find */
3737     Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "unable to find exception handler";
3738     return reg_types_.Conflict();
3739   }
3740   return *common_super;
3741 }
3742 
ResolveMethodAndCheckAccess(uint32_t dex_method_idx,MethodType method_type)3743 ArtMethod* MethodVerifier::ResolveMethodAndCheckAccess(
3744     uint32_t dex_method_idx, MethodType method_type) {
3745   const DexFile::MethodId& method_id = dex_file_->GetMethodId(dex_method_idx);
3746   const RegType& klass_type = ResolveClassAndCheckAccess(method_id.class_idx_);
3747   if (klass_type.IsConflict()) {
3748     std::string append(" in attempt to access method ");
3749     append += dex_file_->GetMethodName(method_id);
3750     AppendToLastFailMessage(append);
3751     return nullptr;
3752   }
3753   if (klass_type.IsUnresolvedTypes()) {
3754     return nullptr;  // Can't resolve Class so no more to do here
3755   }
3756   mirror::Class* klass = klass_type.GetClass();
3757   const RegType& referrer = GetDeclaringClass();
3758   auto* cl = Runtime::Current()->GetClassLinker();
3759   auto pointer_size = cl->GetImagePointerSize();
3760 
3761   ArtMethod* res_method = dex_cache_->GetResolvedMethod(dex_method_idx, pointer_size);
3762   bool stash_method = false;
3763   if (res_method == nullptr) {
3764     const char* name = dex_file_->GetMethodName(method_id);
3765     const Signature signature = dex_file_->GetMethodSignature(method_id);
3766 
3767     if (method_type == METHOD_DIRECT || method_type == METHOD_STATIC) {
3768       res_method = klass->FindDirectMethod(name, signature, pointer_size);
3769     } else if (method_type == METHOD_INTERFACE) {
3770       res_method = klass->FindInterfaceMethod(name, signature, pointer_size);
3771     } else if (method_type == METHOD_SUPER && klass->IsInterface()) {
3772       res_method = klass->FindInterfaceMethod(name, signature, pointer_size);
3773     } else {
3774       DCHECK(method_type == METHOD_VIRTUAL || method_type == METHOD_SUPER);
3775       res_method = klass->FindVirtualMethod(name, signature, pointer_size);
3776     }
3777     if (res_method != nullptr) {
3778       stash_method = true;
3779     } else {
3780       // If a virtual or interface method wasn't found with the expected type, look in
3781       // the direct methods. This can happen when the wrong invoke type is used or when
3782       // a class has changed, and will be flagged as an error in later checks.
3783       if (method_type == METHOD_INTERFACE ||
3784           method_type == METHOD_VIRTUAL ||
3785           method_type == METHOD_SUPER) {
3786         res_method = klass->FindDirectMethod(name, signature, pointer_size);
3787       }
3788       if (res_method == nullptr) {
3789         Fail(VERIFY_ERROR_NO_METHOD) << "couldn't find method "
3790                                      << PrettyDescriptor(klass) << "." << name
3791                                      << " " << signature;
3792         return nullptr;
3793       }
3794     }
3795   }
3796   // Make sure calls to constructors are "direct". There are additional restrictions but we don't
3797   // enforce them here.
3798   if (res_method->IsConstructor() && method_type != METHOD_DIRECT) {
3799     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "rejecting non-direct call to constructor "
3800                                       << PrettyMethod(res_method);
3801     return nullptr;
3802   }
3803   // Disallow any calls to class initializers.
3804   if (res_method->IsClassInitializer()) {
3805     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "rejecting call to class initializer "
3806                                       << PrettyMethod(res_method);
3807     return nullptr;
3808   }
3809 
3810   // Check that interface methods are static or match interface classes.
3811   // We only allow statics if we don't have default methods enabled.
3812   //
3813   // Note: this check must be after the initializer check, as those are required to fail a class,
3814   //       while this check implies an IncompatibleClassChangeError.
3815   if (klass->IsInterface()) {
3816     // methods called on interfaces should be invoke-interface, invoke-super, invoke-direct (if
3817     // dex file version is 37 or greater), or invoke-static.
3818     if (method_type != METHOD_INTERFACE &&
3819         method_type != METHOD_STATIC &&
3820         ((dex_file_->GetVersion() < DexFile::kDefaultMethodsVersion) ||
3821          method_type != METHOD_DIRECT) &&
3822         method_type != METHOD_SUPER) {
3823       Fail(VERIFY_ERROR_CLASS_CHANGE)
3824           << "non-interface method " << PrettyMethod(dex_method_idx, *dex_file_)
3825           << " is in an interface class " << PrettyClass(klass);
3826       return nullptr;
3827     }
3828   } else {
3829     if (method_type == METHOD_INTERFACE) {
3830       Fail(VERIFY_ERROR_CLASS_CHANGE)
3831           << "interface method " << PrettyMethod(dex_method_idx, *dex_file_)
3832           << " is in a non-interface class " << PrettyClass(klass);
3833       return nullptr;
3834     }
3835   }
3836 
3837   // Only stash after the above passed. Otherwise the method wasn't guaranteed to be correct.
3838   if (stash_method) {
3839     dex_cache_->SetResolvedMethod(dex_method_idx, res_method, pointer_size);
3840   }
3841 
3842   // Check if access is allowed.
3843   if (!referrer.CanAccessMember(res_method->GetDeclaringClass(), res_method->GetAccessFlags())) {
3844     Fail(VERIFY_ERROR_ACCESS_METHOD) << "illegal method access (call " << PrettyMethod(res_method)
3845                                      << " from " << referrer << ")";
3846     return res_method;
3847   }
3848   // Check that invoke-virtual and invoke-super are not used on private methods of the same class.
3849   if (res_method->IsPrivate() && (method_type == METHOD_VIRTUAL || method_type == METHOD_SUPER)) {
3850     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invoke-super/virtual can't be used on private method "
3851                                       << PrettyMethod(res_method);
3852     return nullptr;
3853   }
3854   // See if the method type implied by the invoke instruction matches the access flags for the
3855   // target method.
3856   if ((method_type == METHOD_DIRECT && (!res_method->IsDirect() || res_method->IsStatic())) ||
3857       (method_type == METHOD_STATIC && !res_method->IsStatic()) ||
3858       ((method_type == METHOD_SUPER ||
3859         method_type == METHOD_VIRTUAL ||
3860         method_type == METHOD_INTERFACE) && res_method->IsDirect())
3861       ) {
3862     Fail(VERIFY_ERROR_CLASS_CHANGE) << "invoke type (" << method_type << ") does not match method "
3863                                        " type of " << PrettyMethod(res_method);
3864     return nullptr;
3865   }
3866   return res_method;
3867 }
3868 
3869 template <class T>
VerifyInvocationArgsFromIterator(T * it,const Instruction * inst,MethodType method_type,bool is_range,ArtMethod * res_method)3870 ArtMethod* MethodVerifier::VerifyInvocationArgsFromIterator(
3871     T* it, const Instruction* inst, MethodType method_type, bool is_range, ArtMethod* res_method) {
3872   // We use vAA as our expected arg count, rather than res_method->insSize, because we need to
3873   // match the call to the signature. Also, we might be calling through an abstract method
3874   // definition (which doesn't have register count values).
3875   const size_t expected_args = (is_range) ? inst->VRegA_3rc() : inst->VRegA_35c();
3876   /* caught by static verifier */
3877   DCHECK(is_range || expected_args <= 5);
3878   if (expected_args > code_item_->outs_size_) {
3879     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid argument count (" << expected_args
3880         << ") exceeds outsSize (" << code_item_->outs_size_ << ")";
3881     return nullptr;
3882   }
3883 
3884   uint32_t arg[5];
3885   if (!is_range) {
3886     inst->GetVarArgs(arg);
3887   }
3888   uint32_t sig_registers = 0;
3889 
3890   /*
3891    * Check the "this" argument, which must be an instance of the class that declared the method.
3892    * For an interface class, we don't do the full interface merge (see JoinClass), so we can't do a
3893    * rigorous check here (which is okay since we have to do it at runtime).
3894    */
3895   if (method_type != METHOD_STATIC) {
3896     const RegType& actual_arg_type = work_line_->GetInvocationThis(this, inst, is_range);
3897     if (actual_arg_type.IsConflict()) {  // GetInvocationThis failed.
3898       CHECK(have_pending_hard_failure_);
3899       return nullptr;
3900     }
3901     bool is_init = false;
3902     if (actual_arg_type.IsUninitializedTypes()) {
3903       if (res_method) {
3904         if (!res_method->IsConstructor()) {
3905           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "'this' arg must be initialized";
3906           return nullptr;
3907         }
3908       } else {
3909         // Check whether the name of the called method is "<init>"
3910         const uint32_t method_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
3911         if (strcmp(dex_file_->GetMethodName(dex_file_->GetMethodId(method_idx)), "<init>") != 0) {
3912           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "'this' arg must be initialized";
3913           return nullptr;
3914         }
3915       }
3916       is_init = true;
3917     }
3918     const RegType& adjusted_type = is_init
3919                                        ? GetRegTypeCache()->FromUninitialized(actual_arg_type)
3920                                        : actual_arg_type;
3921     if (method_type != METHOD_INTERFACE && !adjusted_type.IsZero()) {
3922       const RegType* res_method_class;
3923       // Miranda methods have the declaring interface as their declaring class, not the abstract
3924       // class. It would be wrong to use this for the type check (interface type checks are
3925       // postponed to runtime).
3926       if (res_method != nullptr && !res_method->IsMiranda()) {
3927         mirror::Class* klass = res_method->GetDeclaringClass();
3928         std::string temp;
3929         res_method_class = &FromClass(klass->GetDescriptor(&temp), klass,
3930                                       klass->CannotBeAssignedFromOtherTypes());
3931       } else {
3932         const uint32_t method_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
3933         const uint16_t class_idx = dex_file_->GetMethodId(method_idx).class_idx_;
3934         res_method_class = &reg_types_.FromDescriptor(
3935             GetClassLoader(),
3936             dex_file_->StringByTypeIdx(class_idx),
3937             false);
3938       }
3939       if (!res_method_class->IsAssignableFrom(adjusted_type)) {
3940         Fail(adjusted_type.IsUnresolvedTypes()
3941                  ? VERIFY_ERROR_NO_CLASS
3942                  : VERIFY_ERROR_BAD_CLASS_SOFT)
3943             << "'this' argument '" << actual_arg_type << "' not instance of '"
3944             << *res_method_class << "'";
3945         // Continue on soft failures. We need to find possible hard failures to avoid problems in
3946         // the compiler.
3947         if (have_pending_hard_failure_) {
3948           return nullptr;
3949         }
3950       }
3951     }
3952     sig_registers = 1;
3953   }
3954 
3955   for ( ; it->HasNext(); it->Next()) {
3956     if (sig_registers >= expected_args) {
3957       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Rejecting invocation, expected " << inst->VRegA() <<
3958           " arguments, found " << sig_registers << " or more.";
3959       return nullptr;
3960     }
3961 
3962     const char* param_descriptor = it->GetDescriptor();
3963 
3964     if (param_descriptor == nullptr) {
3965       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Rejecting invocation because of missing signature "
3966           "component";
3967       return nullptr;
3968     }
3969 
3970     const RegType& reg_type = reg_types_.FromDescriptor(GetClassLoader(), param_descriptor, false);
3971     uint32_t get_reg = is_range ? inst->VRegC_3rc() + static_cast<uint32_t>(sig_registers) :
3972         arg[sig_registers];
3973     if (reg_type.IsIntegralTypes()) {
3974       const RegType& src_type = work_line_->GetRegisterType(this, get_reg);
3975       if (!src_type.IsIntegralTypes()) {
3976         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "register v" << get_reg << " has type " << src_type
3977             << " but expected " << reg_type;
3978         return nullptr;
3979       }
3980     } else {
3981       if (!work_line_->VerifyRegisterType(this, get_reg, reg_type)) {
3982         // Continue on soft failures. We need to find possible hard failures to avoid problems in
3983         // the compiler.
3984         if (have_pending_hard_failure_) {
3985           return nullptr;
3986         }
3987       } else if (reg_type.IsLongOrDoubleTypes()) {
3988         // Check that registers are consecutive (for non-range invokes). Invokes are the only
3989         // instructions not specifying register pairs by the first component, but require them
3990         // nonetheless. Only check when there's an actual register in the parameters. If there's
3991         // none, this will fail below.
3992         if (!is_range && sig_registers + 1 < expected_args) {
3993           uint32_t second_reg = arg[sig_registers + 1];
3994           if (second_reg != get_reg + 1) {
3995             Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Rejecting invocation, long or double parameter "
3996                 "at index " << sig_registers << " is not a pair: " << get_reg << " + "
3997                 << second_reg << ".";
3998             return nullptr;
3999           }
4000         }
4001       }
4002     }
4003     sig_registers += reg_type.IsLongOrDoubleTypes() ?  2 : 1;
4004   }
4005   if (expected_args != sig_registers) {
4006     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Rejecting invocation, expected " << expected_args <<
4007         " arguments, found " << sig_registers;
4008     return nullptr;
4009   }
4010   return res_method;
4011 }
4012 
VerifyInvocationArgsUnresolvedMethod(const Instruction * inst,MethodType method_type,bool is_range)4013 void MethodVerifier::VerifyInvocationArgsUnresolvedMethod(const Instruction* inst,
4014                                                           MethodType method_type,
4015                                                           bool is_range) {
4016   // As the method may not have been resolved, make this static check against what we expect.
4017   // The main reason for this code block is to fail hard when we find an illegal use, e.g.,
4018   // wrong number of arguments or wrong primitive types, even if the method could not be resolved.
4019   const uint32_t method_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
4020   DexFileParameterIterator it(*dex_file_,
4021                               dex_file_->GetProtoId(dex_file_->GetMethodId(method_idx).proto_idx_));
4022   VerifyInvocationArgsFromIterator<DexFileParameterIterator>(&it, inst, method_type, is_range,
4023                                                              nullptr);
4024 }
4025 
4026 class MethodParamListDescriptorIterator {
4027  public:
MethodParamListDescriptorIterator(ArtMethod * res_method)4028   explicit MethodParamListDescriptorIterator(ArtMethod* res_method) :
4029       res_method_(res_method), pos_(0), params_(res_method->GetParameterTypeList()),
4030       params_size_(params_ == nullptr ? 0 : params_->Size()) {
4031   }
4032 
HasNext()4033   bool HasNext() {
4034     return pos_ < params_size_;
4035   }
4036 
Next()4037   void Next() {
4038     ++pos_;
4039   }
4040 
GetDescriptor()4041   const char* GetDescriptor() SHARED_REQUIRES(Locks::mutator_lock_) {
4042     return res_method_->GetTypeDescriptorFromTypeIdx(params_->GetTypeItem(pos_).type_idx_);
4043   }
4044 
4045  private:
4046   ArtMethod* res_method_;
4047   size_t pos_;
4048   const DexFile::TypeList* params_;
4049   const size_t params_size_;
4050 };
4051 
VerifyInvocationArgs(const Instruction * inst,MethodType method_type,bool is_range)4052 ArtMethod* MethodVerifier::VerifyInvocationArgs(
4053     const Instruction* inst, MethodType method_type, bool is_range) {
4054   // Resolve the method. This could be an abstract or concrete method depending on what sort of call
4055   // we're making.
4056   const uint32_t method_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
4057 
4058   ArtMethod* res_method = ResolveMethodAndCheckAccess(method_idx, method_type);
4059   if (res_method == nullptr) {  // error or class is unresolved
4060     // Check what we can statically.
4061     if (!have_pending_hard_failure_) {
4062       VerifyInvocationArgsUnresolvedMethod(inst, method_type, is_range);
4063     }
4064     return nullptr;
4065   }
4066 
4067   // If we're using invoke-super(method), make sure that the executing method's class' superclass
4068   // has a vtable entry for the target method. Or the target is on a interface.
4069   if (method_type == METHOD_SUPER) {
4070     uint16_t class_idx = dex_file_->GetMethodId(method_idx).class_idx_;
4071     mirror::Class* reference_class = dex_cache_->GetResolvedType(class_idx);
4072     if (reference_class == nullptr) {
4073       Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "Unable to find referenced class from invoke-super";
4074       return nullptr;
4075     }
4076     if (reference_class->IsInterface()) {
4077       // TODO Can we verify anything else.
4078       if (class_idx == class_def_->class_idx_) {
4079         Fail(VERIFY_ERROR_CLASS_CHANGE) << "Cannot invoke-super on self as interface";
4080         return nullptr;
4081       }
4082       // TODO Revisit whether we want to allow invoke-super on direct interfaces only like the JLS
4083       // does.
4084       if (!GetDeclaringClass().HasClass()) {
4085         Fail(VERIFY_ERROR_NO_CLASS) << "Unable to resolve the full class of 'this' used in an"
4086                                     << "interface invoke-super";
4087         return nullptr;
4088       } else if (!reference_class->IsAssignableFrom(GetDeclaringClass().GetClass())) {
4089         Fail(VERIFY_ERROR_CLASS_CHANGE)
4090             << "invoke-super in " << PrettyClass(GetDeclaringClass().GetClass()) << " in method "
4091             << PrettyMethod(dex_method_idx_, *dex_file_) << " to method "
4092             << PrettyMethod(method_idx, *dex_file_) << " references "
4093             << "non-super-interface type " << PrettyClass(reference_class);
4094         return nullptr;
4095       }
4096     } else {
4097       const RegType& super = GetDeclaringClass().GetSuperClass(&reg_types_);
4098       if (super.IsUnresolvedTypes()) {
4099         Fail(VERIFY_ERROR_NO_METHOD) << "unknown super class in invoke-super from "
4100                                     << PrettyMethod(dex_method_idx_, *dex_file_)
4101                                     << " to super " << PrettyMethod(res_method);
4102         return nullptr;
4103       }
4104       if (!reference_class->IsAssignableFrom(GetDeclaringClass().GetClass()) ||
4105           (res_method->GetMethodIndex() >= super.GetClass()->GetVTableLength())) {
4106         Fail(VERIFY_ERROR_NO_METHOD) << "invalid invoke-super from "
4107                                     << PrettyMethod(dex_method_idx_, *dex_file_)
4108                                     << " to super " << super
4109                                     << "." << res_method->GetName()
4110                                     << res_method->GetSignature();
4111         return nullptr;
4112       }
4113     }
4114   }
4115 
4116   // Process the target method's signature. This signature may or may not
4117   MethodParamListDescriptorIterator it(res_method);
4118   return VerifyInvocationArgsFromIterator<MethodParamListDescriptorIterator>(&it, inst, method_type,
4119                                                                              is_range, res_method);
4120 }
4121 
GetQuickInvokedMethod(const Instruction * inst,RegisterLine * reg_line,bool is_range,bool allow_failure)4122 ArtMethod* MethodVerifier::GetQuickInvokedMethod(const Instruction* inst, RegisterLine* reg_line,
4123                                                  bool is_range, bool allow_failure) {
4124   if (is_range) {
4125     DCHECK_EQ(inst->Opcode(), Instruction::INVOKE_VIRTUAL_RANGE_QUICK);
4126   } else {
4127     DCHECK_EQ(inst->Opcode(), Instruction::INVOKE_VIRTUAL_QUICK);
4128   }
4129   const RegType& actual_arg_type = reg_line->GetInvocationThis(this, inst, is_range, allow_failure);
4130   if (!actual_arg_type.HasClass()) {
4131     VLOG(verifier) << "Failed to get mirror::Class* from '" << actual_arg_type << "'";
4132     return nullptr;
4133   }
4134   mirror::Class* klass = actual_arg_type.GetClass();
4135   mirror::Class* dispatch_class;
4136   if (klass->IsInterface()) {
4137     // Derive Object.class from Class.class.getSuperclass().
4138     mirror::Class* object_klass = klass->GetClass()->GetSuperClass();
4139     if (FailOrAbort(this, object_klass->IsObjectClass(),
4140                     "Failed to find Object class in quickened invoke receiver", work_insn_idx_)) {
4141       return nullptr;
4142     }
4143     dispatch_class = object_klass;
4144   } else {
4145     dispatch_class = klass;
4146   }
4147   if (!dispatch_class->HasVTable()) {
4148     FailOrAbort(this, allow_failure, "Receiver class has no vtable for quickened invoke at ",
4149                 work_insn_idx_);
4150     return nullptr;
4151   }
4152   uint16_t vtable_index = is_range ? inst->VRegB_3rc() : inst->VRegB_35c();
4153   auto* cl = Runtime::Current()->GetClassLinker();
4154   auto pointer_size = cl->GetImagePointerSize();
4155   if (static_cast<int32_t>(vtable_index) >= dispatch_class->GetVTableLength()) {
4156     FailOrAbort(this, allow_failure,
4157                 "Receiver class has not enough vtable slots for quickened invoke at ",
4158                 work_insn_idx_);
4159     return nullptr;
4160   }
4161   ArtMethod* res_method = dispatch_class->GetVTableEntry(vtable_index, pointer_size);
4162   if (self_->IsExceptionPending()) {
4163     FailOrAbort(this, allow_failure, "Unexpected exception pending for quickened invoke at ",
4164                 work_insn_idx_);
4165     return nullptr;
4166   }
4167   return res_method;
4168 }
4169 
VerifyInvokeVirtualQuickArgs(const Instruction * inst,bool is_range)4170 ArtMethod* MethodVerifier::VerifyInvokeVirtualQuickArgs(const Instruction* inst, bool is_range) {
4171   DCHECK(Runtime::Current()->IsStarted() || verify_to_dump_)
4172       << PrettyMethod(dex_method_idx_, *dex_file_, true) << "@" << work_insn_idx_;
4173 
4174   ArtMethod* res_method = GetQuickInvokedMethod(inst, work_line_.get(), is_range, false);
4175   if (res_method == nullptr) {
4176     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Cannot infer method from " << inst->Name();
4177     return nullptr;
4178   }
4179   if (FailOrAbort(this, !res_method->IsDirect(), "Quick-invoked method is direct at ",
4180                   work_insn_idx_)) {
4181     return nullptr;
4182   }
4183   if (FailOrAbort(this, !res_method->IsStatic(), "Quick-invoked method is static at ",
4184                   work_insn_idx_)) {
4185     return nullptr;
4186   }
4187 
4188   // We use vAA as our expected arg count, rather than res_method->insSize, because we need to
4189   // match the call to the signature. Also, we might be calling through an abstract method
4190   // definition (which doesn't have register count values).
4191   const RegType& actual_arg_type = work_line_->GetInvocationThis(this, inst, is_range);
4192   if (actual_arg_type.IsConflict()) {  // GetInvocationThis failed.
4193     return nullptr;
4194   }
4195   const size_t expected_args = (is_range) ? inst->VRegA_3rc() : inst->VRegA_35c();
4196   /* caught by static verifier */
4197   DCHECK(is_range || expected_args <= 5);
4198   if (expected_args > code_item_->outs_size_) {
4199     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid argument count (" << expected_args
4200         << ") exceeds outsSize (" << code_item_->outs_size_ << ")";
4201     return nullptr;
4202   }
4203 
4204   /*
4205    * Check the "this" argument, which must be an instance of the class that declared the method.
4206    * For an interface class, we don't do the full interface merge (see JoinClass), so we can't do a
4207    * rigorous check here (which is okay since we have to do it at runtime).
4208    */
4209   // Note: given an uninitialized type, this should always fail. Constructors aren't virtual.
4210   if (actual_arg_type.IsUninitializedTypes() && !res_method->IsConstructor()) {
4211     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "'this' arg must be initialized";
4212     return nullptr;
4213   }
4214   if (!actual_arg_type.IsZero()) {
4215     mirror::Class* klass = res_method->GetDeclaringClass();
4216     std::string temp;
4217     const RegType& res_method_class =
4218         FromClass(klass->GetDescriptor(&temp), klass, klass->CannotBeAssignedFromOtherTypes());
4219     if (!res_method_class.IsAssignableFrom(actual_arg_type)) {
4220       Fail(actual_arg_type.IsUninitializedTypes()    // Just overcautious - should have never
4221                ? VERIFY_ERROR_BAD_CLASS_HARD         // quickened this.
4222                : actual_arg_type.IsUnresolvedTypes()
4223                      ? VERIFY_ERROR_NO_CLASS
4224                      : VERIFY_ERROR_BAD_CLASS_SOFT) << "'this' argument '" << actual_arg_type
4225           << "' not instance of '" << res_method_class << "'";
4226       return nullptr;
4227     }
4228   }
4229   /*
4230    * Process the target method's signature. This signature may or may not
4231    * have been verified, so we can't assume it's properly formed.
4232    */
4233   const DexFile::TypeList* params = res_method->GetParameterTypeList();
4234   size_t params_size = params == nullptr ? 0 : params->Size();
4235   uint32_t arg[5];
4236   if (!is_range) {
4237     inst->GetVarArgs(arg);
4238   }
4239   size_t actual_args = 1;
4240   for (size_t param_index = 0; param_index < params_size; param_index++) {
4241     if (actual_args >= expected_args) {
4242       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Rejecting invalid call to '" << PrettyMethod(res_method)
4243                                         << "'. Expected " << expected_args
4244                                          << " arguments, processing argument " << actual_args
4245                                         << " (where longs/doubles count twice).";
4246       return nullptr;
4247     }
4248     const char* descriptor =
4249         res_method->GetTypeDescriptorFromTypeIdx(params->GetTypeItem(param_index).type_idx_);
4250     if (descriptor == nullptr) {
4251       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Rejecting invocation of " << PrettyMethod(res_method)
4252                                         << " missing signature component";
4253       return nullptr;
4254     }
4255     const RegType& reg_type = reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
4256     uint32_t get_reg = is_range ? inst->VRegC_3rc() + actual_args : arg[actual_args];
4257     if (!work_line_->VerifyRegisterType(this, get_reg, reg_type)) {
4258       return res_method;
4259     }
4260     actual_args = reg_type.IsLongOrDoubleTypes() ? actual_args + 2 : actual_args + 1;
4261   }
4262   if (actual_args != expected_args) {
4263     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Rejecting invocation of " << PrettyMethod(res_method)
4264               << " expected " << expected_args << " arguments, found " << actual_args;
4265     return nullptr;
4266   } else {
4267     return res_method;
4268   }
4269 }
4270 
VerifyNewArray(const Instruction * inst,bool is_filled,bool is_range)4271 void MethodVerifier::VerifyNewArray(const Instruction* inst, bool is_filled, bool is_range) {
4272   uint32_t type_idx;
4273   if (!is_filled) {
4274     DCHECK_EQ(inst->Opcode(), Instruction::NEW_ARRAY);
4275     type_idx = inst->VRegC_22c();
4276   } else if (!is_range) {
4277     DCHECK_EQ(inst->Opcode(), Instruction::FILLED_NEW_ARRAY);
4278     type_idx = inst->VRegB_35c();
4279   } else {
4280     DCHECK_EQ(inst->Opcode(), Instruction::FILLED_NEW_ARRAY_RANGE);
4281     type_idx = inst->VRegB_3rc();
4282   }
4283   const RegType& res_type = ResolveClassAndCheckAccess(type_idx);
4284   if (res_type.IsConflict()) {  // bad class
4285     DCHECK_NE(failures_.size(), 0U);
4286   } else {
4287     // TODO: check Compiler::CanAccessTypeWithoutChecks returns false when res_type is unresolved
4288     if (!res_type.IsArrayTypes()) {
4289       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "new-array on non-array class " << res_type;
4290     } else if (!is_filled) {
4291       /* make sure "size" register is valid type */
4292       work_line_->VerifyRegisterType(this, inst->VRegB_22c(), reg_types_.Integer());
4293       /* set register type to array class */
4294       const RegType& precise_type = reg_types_.FromUninitialized(res_type);
4295       work_line_->SetRegisterType<LockOp::kClear>(this, inst->VRegA_22c(), precise_type);
4296     } else {
4297       DCHECK(!res_type.IsUnresolvedMergedReference());
4298       // Verify each register. If "arg_count" is bad, VerifyRegisterType() will run off the end of
4299       // the list and fail. It's legal, if silly, for arg_count to be zero.
4300       const RegType& expected_type = reg_types_.GetComponentType(res_type, GetClassLoader());
4301       uint32_t arg_count = (is_range) ? inst->VRegA_3rc() : inst->VRegA_35c();
4302       uint32_t arg[5];
4303       if (!is_range) {
4304         inst->GetVarArgs(arg);
4305       }
4306       for (size_t ui = 0; ui < arg_count; ui++) {
4307         uint32_t get_reg = is_range ? inst->VRegC_3rc() + ui : arg[ui];
4308         if (!work_line_->VerifyRegisterType(this, get_reg, expected_type)) {
4309           work_line_->SetResultRegisterType(this, reg_types_.Conflict());
4310           return;
4311         }
4312       }
4313       // filled-array result goes into "result" register
4314       const RegType& precise_type = reg_types_.FromUninitialized(res_type);
4315       work_line_->SetResultRegisterType(this, precise_type);
4316     }
4317   }
4318 }
4319 
VerifyAGet(const Instruction * inst,const RegType & insn_type,bool is_primitive)4320 void MethodVerifier::VerifyAGet(const Instruction* inst,
4321                                 const RegType& insn_type, bool is_primitive) {
4322   const RegType& index_type = work_line_->GetRegisterType(this, inst->VRegC_23x());
4323   if (!index_type.IsArrayIndexTypes()) {
4324     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Invalid reg type for array index (" << index_type << ")";
4325   } else {
4326     const RegType& array_type = work_line_->GetRegisterType(this, inst->VRegB_23x());
4327     if (array_type.IsZero()) {
4328       have_pending_runtime_throw_failure_ = true;
4329       // Null array class; this code path will fail at runtime. Infer a merge-able type from the
4330       // instruction type. TODO: have a proper notion of bottom here.
4331       if (!is_primitive || insn_type.IsCategory1Types()) {
4332         // Reference or category 1
4333         work_line_->SetRegisterType<LockOp::kClear>(this, inst->VRegA_23x(), reg_types_.Zero());
4334       } else {
4335         // Category 2
4336         work_line_->SetRegisterTypeWide(this, inst->VRegA_23x(),
4337                                         reg_types_.FromCat2ConstLo(0, false),
4338                                         reg_types_.FromCat2ConstHi(0, false));
4339       }
4340     } else if (!array_type.IsArrayTypes()) {
4341       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "not array type " << array_type << " with aget";
4342     } else if (array_type.IsUnresolvedMergedReference()) {
4343       // Unresolved array types must be reference array types.
4344       if (is_primitive) {
4345         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "reference array type " << array_type
4346                     << " source for category 1 aget";
4347       } else {
4348         Fail(VERIFY_ERROR_NO_CLASS) << "cannot verify aget for " << array_type
4349             << " because of missing class";
4350         // Approximate with java.lang.Object[].
4351         work_line_->SetRegisterType<LockOp::kClear>(this,
4352                                                     inst->VRegA_23x(),
4353                                                     reg_types_.JavaLangObject(false));
4354       }
4355     } else {
4356       /* verify the class */
4357       const RegType& component_type = reg_types_.GetComponentType(array_type, GetClassLoader());
4358       if (!component_type.IsReferenceTypes() && !is_primitive) {
4359         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "primitive array type " << array_type
4360             << " source for aget-object";
4361       } else if (component_type.IsNonZeroReferenceTypes() && is_primitive) {
4362         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "reference array type " << array_type
4363             << " source for category 1 aget";
4364       } else if (is_primitive && !insn_type.Equals(component_type) &&
4365                  !((insn_type.IsInteger() && component_type.IsFloat()) ||
4366                  (insn_type.IsLong() && component_type.IsDouble()))) {
4367         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "array type " << array_type
4368             << " incompatible with aget of type " << insn_type;
4369       } else {
4370         // Use knowledge of the field type which is stronger than the type inferred from the
4371         // instruction, which can't differentiate object types and ints from floats, longs from
4372         // doubles.
4373         if (!component_type.IsLowHalf()) {
4374           work_line_->SetRegisterType<LockOp::kClear>(this, inst->VRegA_23x(), component_type);
4375         } else {
4376           work_line_->SetRegisterTypeWide(this, inst->VRegA_23x(), component_type,
4377                                           component_type.HighHalf(&reg_types_));
4378         }
4379       }
4380     }
4381   }
4382 }
4383 
VerifyPrimitivePut(const RegType & target_type,const RegType & insn_type,const uint32_t vregA)4384 void MethodVerifier::VerifyPrimitivePut(const RegType& target_type, const RegType& insn_type,
4385                                         const uint32_t vregA) {
4386   // Primitive assignability rules are weaker than regular assignability rules.
4387   bool instruction_compatible;
4388   bool value_compatible;
4389   const RegType& value_type = work_line_->GetRegisterType(this, vregA);
4390   if (target_type.IsIntegralTypes()) {
4391     instruction_compatible = target_type.Equals(insn_type);
4392     value_compatible = value_type.IsIntegralTypes();
4393   } else if (target_type.IsFloat()) {
4394     instruction_compatible = insn_type.IsInteger();  // no put-float, so expect put-int
4395     value_compatible = value_type.IsFloatTypes();
4396   } else if (target_type.IsLong()) {
4397     instruction_compatible = insn_type.IsLong();
4398     // Additional register check: this is not checked statically (as part of VerifyInstructions),
4399     // as target_type depends on the resolved type of the field.
4400     if (instruction_compatible && work_line_->NumRegs() > vregA + 1) {
4401       const RegType& value_type_hi = work_line_->GetRegisterType(this, vregA + 1);
4402       value_compatible = value_type.IsLongTypes() && value_type.CheckWidePair(value_type_hi);
4403     } else {
4404       value_compatible = false;
4405     }
4406   } else if (target_type.IsDouble()) {
4407     instruction_compatible = insn_type.IsLong();  // no put-double, so expect put-long
4408     // Additional register check: this is not checked statically (as part of VerifyInstructions),
4409     // as target_type depends on the resolved type of the field.
4410     if (instruction_compatible && work_line_->NumRegs() > vregA + 1) {
4411       const RegType& value_type_hi = work_line_->GetRegisterType(this, vregA + 1);
4412       value_compatible = value_type.IsDoubleTypes() && value_type.CheckWidePair(value_type_hi);
4413     } else {
4414       value_compatible = false;
4415     }
4416   } else {
4417     instruction_compatible = false;  // reference with primitive store
4418     value_compatible = false;  // unused
4419   }
4420   if (!instruction_compatible) {
4421     // This is a global failure rather than a class change failure as the instructions and
4422     // the descriptors for the type should have been consistent within the same file at
4423     // compile time.
4424     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "put insn has type '" << insn_type
4425         << "' but expected type '" << target_type << "'";
4426     return;
4427   }
4428   if (!value_compatible) {
4429     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unexpected value in v" << vregA
4430         << " of type " << value_type << " but expected " << target_type << " for put";
4431     return;
4432   }
4433 }
4434 
VerifyAPut(const Instruction * inst,const RegType & insn_type,bool is_primitive)4435 void MethodVerifier::VerifyAPut(const Instruction* inst,
4436                                 const RegType& insn_type, bool is_primitive) {
4437   const RegType& index_type = work_line_->GetRegisterType(this, inst->VRegC_23x());
4438   if (!index_type.IsArrayIndexTypes()) {
4439     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Invalid reg type for array index (" << index_type << ")";
4440   } else {
4441     const RegType& array_type = work_line_->GetRegisterType(this, inst->VRegB_23x());
4442     if (array_type.IsZero()) {
4443       // Null array type; this code path will fail at runtime.
4444       // Still check that the given value matches the instruction's type.
4445       // Note: this is, as usual, complicated by the fact the the instruction isn't fully typed
4446       //       and fits multiple register types.
4447       const RegType* modified_reg_type = &insn_type;
4448       if ((modified_reg_type == &reg_types_.Integer()) ||
4449           (modified_reg_type == &reg_types_.LongLo())) {
4450         // May be integer or float | long or double. Overwrite insn_type accordingly.
4451         const RegType& value_type = work_line_->GetRegisterType(this, inst->VRegA_23x());
4452         if (modified_reg_type == &reg_types_.Integer()) {
4453           if (&value_type == &reg_types_.Float()) {
4454             modified_reg_type = &value_type;
4455           }
4456         } else {
4457           if (&value_type == &reg_types_.DoubleLo()) {
4458             modified_reg_type = &value_type;
4459           }
4460         }
4461       }
4462       work_line_->VerifyRegisterType(this, inst->VRegA_23x(), *modified_reg_type);
4463     } else if (!array_type.IsArrayTypes()) {
4464       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "not array type " << array_type << " with aput";
4465     } else if (array_type.IsUnresolvedMergedReference()) {
4466       // Unresolved array types must be reference array types.
4467       if (is_primitive) {
4468         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "put insn has type '" << insn_type
4469                                           << "' but unresolved type '" << array_type << "'";
4470       } else {
4471         Fail(VERIFY_ERROR_NO_CLASS) << "cannot verify aput for " << array_type
4472                                     << " because of missing class";
4473       }
4474     } else {
4475       const RegType& component_type = reg_types_.GetComponentType(array_type, GetClassLoader());
4476       const uint32_t vregA = inst->VRegA_23x();
4477       if (is_primitive) {
4478         VerifyPrimitivePut(component_type, insn_type, vregA);
4479       } else {
4480         if (!component_type.IsReferenceTypes()) {
4481           Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "primitive array type " << array_type
4482               << " source for aput-object";
4483         } else {
4484           // The instruction agrees with the type of array, confirm the value to be stored does too
4485           // Note: we use the instruction type (rather than the component type) for aput-object as
4486           // incompatible classes will be caught at runtime as an array store exception
4487           work_line_->VerifyRegisterType(this, vregA, insn_type);
4488         }
4489       }
4490     }
4491   }
4492 }
4493 
GetStaticField(int field_idx)4494 ArtField* MethodVerifier::GetStaticField(int field_idx) {
4495   const DexFile::FieldId& field_id = dex_file_->GetFieldId(field_idx);
4496   // Check access to class
4497   const RegType& klass_type = ResolveClassAndCheckAccess(field_id.class_idx_);
4498   if (klass_type.IsConflict()) {  // bad class
4499     AppendToLastFailMessage(StringPrintf(" in attempt to access static field %d (%s) in %s",
4500                                          field_idx, dex_file_->GetFieldName(field_id),
4501                                          dex_file_->GetFieldDeclaringClassDescriptor(field_id)));
4502     return nullptr;
4503   }
4504   if (klass_type.IsUnresolvedTypes()) {
4505     return nullptr;  // Can't resolve Class so no more to do here, will do checking at runtime.
4506   }
4507   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
4508   ArtField* field = class_linker->ResolveFieldJLS(*dex_file_, field_idx, dex_cache_,
4509                                                   class_loader_);
4510   if (field == nullptr) {
4511     VLOG(verifier) << "Unable to resolve static field " << field_idx << " ("
4512               << dex_file_->GetFieldName(field_id) << ") in "
4513               << dex_file_->GetFieldDeclaringClassDescriptor(field_id);
4514     DCHECK(self_->IsExceptionPending());
4515     self_->ClearException();
4516     return nullptr;
4517   } else if (!GetDeclaringClass().CanAccessMember(field->GetDeclaringClass(),
4518                                                   field->GetAccessFlags())) {
4519     Fail(VERIFY_ERROR_ACCESS_FIELD) << "cannot access static field " << PrettyField(field)
4520                                     << " from " << GetDeclaringClass();
4521     return nullptr;
4522   } else if (!field->IsStatic()) {
4523     Fail(VERIFY_ERROR_CLASS_CHANGE) << "expected field " << PrettyField(field) << " to be static";
4524     return nullptr;
4525   }
4526   return field;
4527 }
4528 
GetInstanceField(const RegType & obj_type,int field_idx)4529 ArtField* MethodVerifier::GetInstanceField(const RegType& obj_type, int field_idx) {
4530   const DexFile::FieldId& field_id = dex_file_->GetFieldId(field_idx);
4531   // Check access to class
4532   const RegType& klass_type = ResolveClassAndCheckAccess(field_id.class_idx_);
4533   if (klass_type.IsConflict()) {
4534     AppendToLastFailMessage(StringPrintf(" in attempt to access instance field %d (%s) in %s",
4535                                          field_idx, dex_file_->GetFieldName(field_id),
4536                                          dex_file_->GetFieldDeclaringClassDescriptor(field_id)));
4537     return nullptr;
4538   }
4539   if (klass_type.IsUnresolvedTypes()) {
4540     return nullptr;  // Can't resolve Class so no more to do here
4541   }
4542   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
4543   ArtField* field = class_linker->ResolveFieldJLS(*dex_file_, field_idx, dex_cache_,
4544                                                   class_loader_);
4545   if (field == nullptr) {
4546     VLOG(verifier) << "Unable to resolve instance field " << field_idx << " ("
4547               << dex_file_->GetFieldName(field_id) << ") in "
4548               << dex_file_->GetFieldDeclaringClassDescriptor(field_id);
4549     DCHECK(self_->IsExceptionPending());
4550     self_->ClearException();
4551     return nullptr;
4552   } else if (!GetDeclaringClass().CanAccessMember(field->GetDeclaringClass(),
4553                                                   field->GetAccessFlags())) {
4554     Fail(VERIFY_ERROR_ACCESS_FIELD) << "cannot access instance field " << PrettyField(field)
4555                                     << " from " << GetDeclaringClass();
4556     return nullptr;
4557   } else if (field->IsStatic()) {
4558     Fail(VERIFY_ERROR_CLASS_CHANGE) << "expected field " << PrettyField(field)
4559                                     << " to not be static";
4560     return nullptr;
4561   } else if (obj_type.IsZero()) {
4562     // Cannot infer and check type, however, access will cause null pointer exception
4563     return field;
4564   } else if (!obj_type.IsReferenceTypes()) {
4565     // Trying to read a field from something that isn't a reference
4566     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "instance field access on object that has "
4567                                       << "non-reference type " << obj_type;
4568     return nullptr;
4569   } else {
4570     mirror::Class* klass = field->GetDeclaringClass();
4571     const RegType& field_klass =
4572         FromClass(dex_file_->GetFieldDeclaringClassDescriptor(field_id),
4573                   klass, klass->CannotBeAssignedFromOtherTypes());
4574     if (obj_type.IsUninitializedTypes()) {
4575       // Field accesses through uninitialized references are only allowable for constructors where
4576       // the field is declared in this class.
4577       // Note: this IsConstructor check is technically redundant, as UninitializedThis should only
4578       //       appear in constructors.
4579       if (!obj_type.IsUninitializedThisReference() ||
4580           !IsConstructor() ||
4581           !field_klass.Equals(GetDeclaringClass())) {
4582         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "cannot access instance field " << PrettyField(field)
4583                                           << " of a not fully initialized object within the context"
4584                                           << " of " << PrettyMethod(dex_method_idx_, *dex_file_);
4585         return nullptr;
4586       }
4587       return field;
4588     } else if (!field_klass.IsAssignableFrom(obj_type)) {
4589       // Trying to access C1.field1 using reference of type C2, which is neither C1 or a sub-class
4590       // of C1. For resolution to occur the declared class of the field must be compatible with
4591       // obj_type, we've discovered this wasn't so, so report the field didn't exist.
4592       VerifyError type;
4593       bool is_aot = Runtime::Current()->IsAotCompiler();
4594       if (is_aot && (field_klass.IsUnresolvedTypes() || obj_type.IsUnresolvedTypes())) {
4595         // Compiler & unresolved types involved, retry at runtime.
4596         type = VerifyError::VERIFY_ERROR_NO_CLASS;
4597       } else {
4598         // Classes known (resolved; and thus assignability check is precise), or we are at runtime
4599         // and still missing classes. This is a hard failure.
4600         type = VerifyError::VERIFY_ERROR_BAD_CLASS_HARD;
4601       }
4602       Fail(type) << "cannot access instance field " << PrettyField(field)
4603                  << " from object of type " << obj_type;
4604       return nullptr;
4605     } else {
4606       return field;
4607     }
4608   }
4609 }
4610 
4611 template <MethodVerifier::FieldAccessType kAccType>
VerifyISFieldAccess(const Instruction * inst,const RegType & insn_type,bool is_primitive,bool is_static)4612 void MethodVerifier::VerifyISFieldAccess(const Instruction* inst, const RegType& insn_type,
4613                                          bool is_primitive, bool is_static) {
4614   uint32_t field_idx = is_static ? inst->VRegB_21c() : inst->VRegC_22c();
4615   ArtField* field;
4616   if (is_static) {
4617     field = GetStaticField(field_idx);
4618   } else {
4619     const RegType& object_type = work_line_->GetRegisterType(this, inst->VRegB_22c());
4620 
4621     // One is not allowed to access fields on uninitialized references, except to write to
4622     // fields in the constructor (before calling another constructor).
4623     // GetInstanceField does an assignability check which will fail for uninitialized types.
4624     // We thus modify the type if the uninitialized reference is a "this" reference (this also
4625     // checks at the same time that we're verifying a constructor).
4626     bool should_adjust = (kAccType == FieldAccessType::kAccPut) &&
4627                          object_type.IsUninitializedThisReference();
4628     const RegType& adjusted_type = should_adjust
4629                                        ? GetRegTypeCache()->FromUninitialized(object_type)
4630                                        : object_type;
4631     field = GetInstanceField(adjusted_type, field_idx);
4632     if (UNLIKELY(have_pending_hard_failure_)) {
4633       return;
4634     }
4635     if (should_adjust) {
4636       if (field == nullptr) {
4637         Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "Might be accessing a superclass instance field prior "
4638                                           << "to the superclass being initialized in "
4639                                           << PrettyMethod(dex_method_idx_, *dex_file_);
4640       } else if (field->GetDeclaringClass() != GetDeclaringClass().GetClass()) {
4641         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "cannot access superclass instance field "
4642                                           << PrettyField(field) << " of a not fully initialized "
4643                                           << "object within the context of "
4644                                           << PrettyMethod(dex_method_idx_, *dex_file_);
4645         return;
4646       }
4647     }
4648   }
4649   const RegType* field_type = nullptr;
4650   if (field != nullptr) {
4651     if (kAccType == FieldAccessType::kAccPut) {
4652       if (field->IsFinal() && field->GetDeclaringClass() != GetDeclaringClass().GetClass()) {
4653         Fail(VERIFY_ERROR_ACCESS_FIELD) << "cannot modify final field " << PrettyField(field)
4654                                         << " from other class " << GetDeclaringClass();
4655         // Keep hunting for possible hard fails.
4656       }
4657     }
4658 
4659     mirror::Class* field_type_class =
4660         can_load_classes_ ? field->GetType<true>() : field->GetType<false>();
4661     if (field_type_class != nullptr) {
4662       field_type = &FromClass(field->GetTypeDescriptor(), field_type_class,
4663                               field_type_class->CannotBeAssignedFromOtherTypes());
4664     } else {
4665       DCHECK(!can_load_classes_ || self_->IsExceptionPending());
4666       self_->ClearException();
4667     }
4668   }
4669   if (field_type == nullptr) {
4670     const DexFile::FieldId& field_id = dex_file_->GetFieldId(field_idx);
4671     const char* descriptor = dex_file_->GetFieldTypeDescriptor(field_id);
4672     field_type = &reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
4673   }
4674   DCHECK(field_type != nullptr);
4675   const uint32_t vregA = (is_static) ? inst->VRegA_21c() : inst->VRegA_22c();
4676   static_assert(kAccType == FieldAccessType::kAccPut || kAccType == FieldAccessType::kAccGet,
4677                 "Unexpected third access type");
4678   if (kAccType == FieldAccessType::kAccPut) {
4679     // sput or iput.
4680     if (is_primitive) {
4681       VerifyPrimitivePut(*field_type, insn_type, vregA);
4682     } else {
4683       if (!insn_type.IsAssignableFrom(*field_type)) {
4684         // If the field type is not a reference, this is a global failure rather than
4685         // a class change failure as the instructions and the descriptors for the type
4686         // should have been consistent within the same file at compile time.
4687         VerifyError error = field_type->IsReferenceTypes() ? VERIFY_ERROR_BAD_CLASS_SOFT
4688                                                            : VERIFY_ERROR_BAD_CLASS_HARD;
4689         Fail(error) << "expected field " << PrettyField(field)
4690                     << " to be compatible with type '" << insn_type
4691                     << "' but found type '" << *field_type
4692                     << "' in put-object";
4693         return;
4694       }
4695       work_line_->VerifyRegisterType(this, vregA, *field_type);
4696     }
4697   } else if (kAccType == FieldAccessType::kAccGet) {
4698     // sget or iget.
4699     if (is_primitive) {
4700       if (field_type->Equals(insn_type) ||
4701           (field_type->IsFloat() && insn_type.IsInteger()) ||
4702           (field_type->IsDouble() && insn_type.IsLong())) {
4703         // expected that read is of the correct primitive type or that int reads are reading
4704         // floats or long reads are reading doubles
4705       } else {
4706         // This is a global failure rather than a class change failure as the instructions and
4707         // the descriptors for the type should have been consistent within the same file at
4708         // compile time
4709         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "expected field " << PrettyField(field)
4710                                           << " to be of type '" << insn_type
4711                                           << "' but found type '" << *field_type << "' in get";
4712         return;
4713       }
4714     } else {
4715       if (!insn_type.IsAssignableFrom(*field_type)) {
4716         // If the field type is not a reference, this is a global failure rather than
4717         // a class change failure as the instructions and the descriptors for the type
4718         // should have been consistent within the same file at compile time.
4719         VerifyError error = field_type->IsReferenceTypes() ? VERIFY_ERROR_BAD_CLASS_SOFT
4720                                                            : VERIFY_ERROR_BAD_CLASS_HARD;
4721         Fail(error) << "expected field " << PrettyField(field)
4722                     << " to be compatible with type '" << insn_type
4723                     << "' but found type '" << *field_type
4724                     << "' in get-object";
4725         if (error != VERIFY_ERROR_BAD_CLASS_HARD) {
4726           work_line_->SetRegisterType<LockOp::kClear>(this, vregA, reg_types_.Conflict());
4727         }
4728         return;
4729       }
4730     }
4731     if (!field_type->IsLowHalf()) {
4732       work_line_->SetRegisterType<LockOp::kClear>(this, vregA, *field_type);
4733     } else {
4734       work_line_->SetRegisterTypeWide(this, vregA, *field_type, field_type->HighHalf(&reg_types_));
4735     }
4736   } else {
4737     LOG(FATAL) << "Unexpected case.";
4738   }
4739 }
4740 
GetQuickFieldAccess(const Instruction * inst,RegisterLine * reg_line)4741 ArtField* MethodVerifier::GetQuickFieldAccess(const Instruction* inst,
4742                                                       RegisterLine* reg_line) {
4743   DCHECK(IsInstructionIGetQuickOrIPutQuick(inst->Opcode())) << inst->Opcode();
4744   const RegType& object_type = reg_line->GetRegisterType(this, inst->VRegB_22c());
4745   if (!object_type.HasClass()) {
4746     VLOG(verifier) << "Failed to get mirror::Class* from '" << object_type << "'";
4747     return nullptr;
4748   }
4749   uint32_t field_offset = static_cast<uint32_t>(inst->VRegC_22c());
4750   ArtField* const f = ArtField::FindInstanceFieldWithOffset(object_type.GetClass(), field_offset);
4751   DCHECK_EQ(f->GetOffset().Uint32Value(), field_offset);
4752   if (f == nullptr) {
4753     VLOG(verifier) << "Failed to find instance field at offset '" << field_offset
4754                    << "' from '" << PrettyDescriptor(object_type.GetClass()) << "'";
4755   }
4756   return f;
4757 }
4758 
4759 template <MethodVerifier::FieldAccessType kAccType>
VerifyQuickFieldAccess(const Instruction * inst,const RegType & insn_type,bool is_primitive)4760 void MethodVerifier::VerifyQuickFieldAccess(const Instruction* inst, const RegType& insn_type,
4761                                             bool is_primitive) {
4762   DCHECK(Runtime::Current()->IsStarted() || verify_to_dump_);
4763 
4764   ArtField* field = GetQuickFieldAccess(inst, work_line_.get());
4765   if (field == nullptr) {
4766     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Cannot infer field from " << inst->Name();
4767     return;
4768   }
4769 
4770   // For an IPUT_QUICK, we now test for final flag of the field.
4771   if (kAccType == FieldAccessType::kAccPut) {
4772     if (field->IsFinal() && field->GetDeclaringClass() != GetDeclaringClass().GetClass()) {
4773       Fail(VERIFY_ERROR_ACCESS_FIELD) << "cannot modify final field " << PrettyField(field)
4774                                       << " from other class " << GetDeclaringClass();
4775       return;
4776     }
4777   }
4778 
4779   // Get the field type.
4780   const RegType* field_type;
4781   {
4782     mirror::Class* field_type_class = can_load_classes_ ? field->GetType<true>() :
4783         field->GetType<false>();
4784 
4785     if (field_type_class != nullptr) {
4786       field_type = &FromClass(field->GetTypeDescriptor(),
4787                               field_type_class,
4788                               field_type_class->CannotBeAssignedFromOtherTypes());
4789     } else {
4790       Thread* self = Thread::Current();
4791       DCHECK(!can_load_classes_ || self->IsExceptionPending());
4792       self->ClearException();
4793       field_type = &reg_types_.FromDescriptor(field->GetDeclaringClass()->GetClassLoader(),
4794                                               field->GetTypeDescriptor(),
4795                                               false);
4796     }
4797     if (field_type == nullptr) {
4798       Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "Cannot infer field type from " << inst->Name();
4799       return;
4800     }
4801   }
4802 
4803   const uint32_t vregA = inst->VRegA_22c();
4804   static_assert(kAccType == FieldAccessType::kAccPut || kAccType == FieldAccessType::kAccGet,
4805                 "Unexpected third access type");
4806   if (kAccType == FieldAccessType::kAccPut) {
4807     if (is_primitive) {
4808       // Primitive field assignability rules are weaker than regular assignability rules
4809       bool instruction_compatible;
4810       bool value_compatible;
4811       const RegType& value_type = work_line_->GetRegisterType(this, vregA);
4812       if (field_type->IsIntegralTypes()) {
4813         instruction_compatible = insn_type.IsIntegralTypes();
4814         value_compatible = value_type.IsIntegralTypes();
4815       } else if (field_type->IsFloat()) {
4816         instruction_compatible = insn_type.IsInteger();  // no [is]put-float, so expect [is]put-int
4817         value_compatible = value_type.IsFloatTypes();
4818       } else if (field_type->IsLong()) {
4819         instruction_compatible = insn_type.IsLong();
4820         value_compatible = value_type.IsLongTypes();
4821       } else if (field_type->IsDouble()) {
4822         instruction_compatible = insn_type.IsLong();  // no [is]put-double, so expect [is]put-long
4823         value_compatible = value_type.IsDoubleTypes();
4824       } else {
4825         instruction_compatible = false;  // reference field with primitive store
4826         value_compatible = false;  // unused
4827       }
4828       if (!instruction_compatible) {
4829         // This is a global failure rather than a class change failure as the instructions and
4830         // the descriptors for the type should have been consistent within the same file at
4831         // compile time
4832         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "expected field " << PrettyField(field)
4833                                           << " to be of type '" << insn_type
4834                                           << "' but found type '" << *field_type
4835                                           << "' in put";
4836         return;
4837       }
4838       if (!value_compatible) {
4839         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "unexpected value in v" << vregA
4840             << " of type " << value_type
4841             << " but expected " << *field_type
4842             << " for store to " << PrettyField(field) << " in put";
4843         return;
4844       }
4845     } else {
4846       if (!insn_type.IsAssignableFrom(*field_type)) {
4847         Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "expected field " << PrettyField(field)
4848                                           << " to be compatible with type '" << insn_type
4849                                           << "' but found type '" << *field_type
4850                                           << "' in put-object";
4851         return;
4852       }
4853       work_line_->VerifyRegisterType(this, vregA, *field_type);
4854     }
4855   } else if (kAccType == FieldAccessType::kAccGet) {
4856     if (is_primitive) {
4857       if (field_type->Equals(insn_type) ||
4858           (field_type->IsFloat() && insn_type.IsIntegralTypes()) ||
4859           (field_type->IsDouble() && insn_type.IsLongTypes())) {
4860         // expected that read is of the correct primitive type or that int reads are reading
4861         // floats or long reads are reading doubles
4862       } else {
4863         // This is a global failure rather than a class change failure as the instructions and
4864         // the descriptors for the type should have been consistent within the same file at
4865         // compile time
4866         Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "expected field " << PrettyField(field)
4867                                           << " to be of type '" << insn_type
4868                                           << "' but found type '" << *field_type << "' in Get";
4869         return;
4870       }
4871     } else {
4872       if (!insn_type.IsAssignableFrom(*field_type)) {
4873         Fail(VERIFY_ERROR_BAD_CLASS_SOFT) << "expected field " << PrettyField(field)
4874                                           << " to be compatible with type '" << insn_type
4875                                           << "' but found type '" << *field_type
4876                                           << "' in get-object";
4877         work_line_->SetRegisterType<LockOp::kClear>(this, vregA, reg_types_.Conflict());
4878         return;
4879       }
4880     }
4881     if (!field_type->IsLowHalf()) {
4882       work_line_->SetRegisterType<LockOp::kClear>(this, vregA, *field_type);
4883     } else {
4884       work_line_->SetRegisterTypeWide(this, vregA, *field_type, field_type->HighHalf(&reg_types_));
4885     }
4886   } else {
4887     LOG(FATAL) << "Unexpected case.";
4888   }
4889 }
4890 
CheckNotMoveException(const uint16_t * insns,int insn_idx)4891 bool MethodVerifier::CheckNotMoveException(const uint16_t* insns, int insn_idx) {
4892   if ((insns[insn_idx] & 0xff) == Instruction::MOVE_EXCEPTION) {
4893     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid use of move-exception";
4894     return false;
4895   }
4896   return true;
4897 }
4898 
CheckNotMoveResult(const uint16_t * insns,int insn_idx)4899 bool MethodVerifier::CheckNotMoveResult(const uint16_t* insns, int insn_idx) {
4900   if (((insns[insn_idx] & 0xff) >= Instruction::MOVE_RESULT) &&
4901       ((insns[insn_idx] & 0xff) <= Instruction::MOVE_RESULT_OBJECT)) {
4902     Fail(VERIFY_ERROR_BAD_CLASS_HARD) << "invalid use of move-result*";
4903     return false;
4904   }
4905   return true;
4906 }
4907 
CheckNotMoveExceptionOrMoveResult(const uint16_t * insns,int insn_idx)4908 bool MethodVerifier::CheckNotMoveExceptionOrMoveResult(const uint16_t* insns, int insn_idx) {
4909   return (CheckNotMoveException(insns, insn_idx) && CheckNotMoveResult(insns, insn_idx));
4910 }
4911 
UpdateRegisters(uint32_t next_insn,RegisterLine * merge_line,bool update_merge_line)4912 bool MethodVerifier::UpdateRegisters(uint32_t next_insn, RegisterLine* merge_line,
4913                                      bool update_merge_line) {
4914   bool changed = true;
4915   RegisterLine* target_line = reg_table_.GetLine(next_insn);
4916   if (!GetInstructionFlags(next_insn).IsVisitedOrChanged()) {
4917     /*
4918      * We haven't processed this instruction before, and we haven't touched the registers here, so
4919      * there's nothing to "merge". Copy the registers over and mark it as changed. (This is the
4920      * only way a register can transition out of "unknown", so this is not just an optimization.)
4921      */
4922     target_line->CopyFromLine(merge_line);
4923     if (GetInstructionFlags(next_insn).IsReturn()) {
4924       // Verify that the monitor stack is empty on return.
4925       merge_line->VerifyMonitorStackEmpty(this);
4926 
4927       // For returns we only care about the operand to the return, all other registers are dead.
4928       // Initialize them as conflicts so they don't add to GC and deoptimization information.
4929       const Instruction* ret_inst = Instruction::At(code_item_->insns_ + next_insn);
4930       AdjustReturnLine(this, ret_inst, target_line);
4931     }
4932   } else {
4933     RegisterLineArenaUniquePtr copy;
4934     if (kDebugVerify) {
4935       copy.reset(RegisterLine::Create(target_line->NumRegs(), this));
4936       copy->CopyFromLine(target_line);
4937     }
4938     changed = target_line->MergeRegisters(this, merge_line);
4939     if (have_pending_hard_failure_) {
4940       return false;
4941     }
4942     if (kDebugVerify && changed) {
4943       LogVerifyInfo() << "Merging at [" << reinterpret_cast<void*>(work_insn_idx_) << "]"
4944                       << " to [" << reinterpret_cast<void*>(next_insn) << "]: " << "\n"
4945                       << copy->Dump(this) << "  MERGE\n"
4946                       << merge_line->Dump(this) << "  ==\n"
4947                       << target_line->Dump(this) << "\n";
4948     }
4949     if (update_merge_line && changed) {
4950       merge_line->CopyFromLine(target_line);
4951     }
4952   }
4953   if (changed) {
4954     GetInstructionFlags(next_insn).SetChanged();
4955   }
4956   return true;
4957 }
4958 
CurrentInsnFlags()4959 InstructionFlags* MethodVerifier::CurrentInsnFlags() {
4960   return &GetInstructionFlags(work_insn_idx_);
4961 }
4962 
GetMethodReturnType()4963 const RegType& MethodVerifier::GetMethodReturnType() {
4964   if (return_type_ == nullptr) {
4965     if (mirror_method_ != nullptr) {
4966       size_t pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize();
4967       mirror::Class* return_type_class = mirror_method_->GetReturnType(can_load_classes_,
4968                                                                        pointer_size);
4969       if (return_type_class != nullptr) {
4970         return_type_ = &FromClass(mirror_method_->GetReturnTypeDescriptor(),
4971                                   return_type_class,
4972                                   return_type_class->CannotBeAssignedFromOtherTypes());
4973       } else {
4974         DCHECK(!can_load_classes_ || self_->IsExceptionPending());
4975         self_->ClearException();
4976       }
4977     }
4978     if (return_type_ == nullptr) {
4979       const DexFile::MethodId& method_id = dex_file_->GetMethodId(dex_method_idx_);
4980       const DexFile::ProtoId& proto_id = dex_file_->GetMethodPrototype(method_id);
4981       uint16_t return_type_idx = proto_id.return_type_idx_;
4982       const char* descriptor = dex_file_->GetTypeDescriptor(dex_file_->GetTypeId(return_type_idx));
4983       return_type_ = &reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
4984     }
4985   }
4986   return *return_type_;
4987 }
4988 
GetDeclaringClass()4989 const RegType& MethodVerifier::GetDeclaringClass() {
4990   if (declaring_class_ == nullptr) {
4991     const DexFile::MethodId& method_id = dex_file_->GetMethodId(dex_method_idx_);
4992     const char* descriptor
4993         = dex_file_->GetTypeDescriptor(dex_file_->GetTypeId(method_id.class_idx_));
4994     if (mirror_method_ != nullptr) {
4995       mirror::Class* klass = mirror_method_->GetDeclaringClass();
4996       declaring_class_ = &FromClass(descriptor, klass, klass->CannotBeAssignedFromOtherTypes());
4997     } else {
4998       declaring_class_ = &reg_types_.FromDescriptor(GetClassLoader(), descriptor, false);
4999     }
5000   }
5001   return *declaring_class_;
5002 }
5003 
DescribeVRegs(uint32_t dex_pc)5004 std::vector<int32_t> MethodVerifier::DescribeVRegs(uint32_t dex_pc) {
5005   RegisterLine* line = reg_table_.GetLine(dex_pc);
5006   DCHECK(line != nullptr) << "No register line at DEX pc " << StringPrintf("0x%x", dex_pc);
5007   std::vector<int32_t> result;
5008   for (size_t i = 0; i < line->NumRegs(); ++i) {
5009     const RegType& type = line->GetRegisterType(this, i);
5010     if (type.IsConstant()) {
5011       result.push_back(type.IsPreciseConstant() ? kConstant : kImpreciseConstant);
5012       const ConstantType* const_val = down_cast<const ConstantType*>(&type);
5013       result.push_back(const_val->ConstantValue());
5014     } else if (type.IsConstantLo()) {
5015       result.push_back(type.IsPreciseConstantLo() ? kConstant : kImpreciseConstant);
5016       const ConstantType* const_val = down_cast<const ConstantType*>(&type);
5017       result.push_back(const_val->ConstantValueLo());
5018     } else if (type.IsConstantHi()) {
5019       result.push_back(type.IsPreciseConstantHi() ? kConstant : kImpreciseConstant);
5020       const ConstantType* const_val = down_cast<const ConstantType*>(&type);
5021       result.push_back(const_val->ConstantValueHi());
5022     } else if (type.IsIntegralTypes()) {
5023       result.push_back(kIntVReg);
5024       result.push_back(0);
5025     } else if (type.IsFloat()) {
5026       result.push_back(kFloatVReg);
5027       result.push_back(0);
5028     } else if (type.IsLong()) {
5029       result.push_back(kLongLoVReg);
5030       result.push_back(0);
5031       result.push_back(kLongHiVReg);
5032       result.push_back(0);
5033       ++i;
5034     } else if (type.IsDouble()) {
5035       result.push_back(kDoubleLoVReg);
5036       result.push_back(0);
5037       result.push_back(kDoubleHiVReg);
5038       result.push_back(0);
5039       ++i;
5040     } else if (type.IsUndefined() || type.IsConflict() || type.IsHighHalf()) {
5041       result.push_back(kUndefined);
5042       result.push_back(0);
5043     } else {
5044       CHECK(type.IsNonZeroReferenceTypes());
5045       result.push_back(kReferenceVReg);
5046       result.push_back(0);
5047     }
5048   }
5049   return result;
5050 }
5051 
DetermineCat1Constant(int32_t value,bool precise)5052 const RegType& MethodVerifier::DetermineCat1Constant(int32_t value, bool precise) {
5053   if (precise) {
5054     // Precise constant type.
5055     return reg_types_.FromCat1Const(value, true);
5056   } else {
5057     // Imprecise constant type.
5058     if (value < -32768) {
5059       return reg_types_.IntConstant();
5060     } else if (value < -128) {
5061       return reg_types_.ShortConstant();
5062     } else if (value < 0) {
5063       return reg_types_.ByteConstant();
5064     } else if (value == 0) {
5065       return reg_types_.Zero();
5066     } else if (value == 1) {
5067       return reg_types_.One();
5068     } else if (value < 128) {
5069       return reg_types_.PosByteConstant();
5070     } else if (value < 32768) {
5071       return reg_types_.PosShortConstant();
5072     } else if (value < 65536) {
5073       return reg_types_.CharConstant();
5074     } else {
5075       return reg_types_.IntConstant();
5076     }
5077   }
5078 }
5079 
Init()5080 void MethodVerifier::Init() {
5081   art::verifier::RegTypeCache::Init();
5082 }
5083 
Shutdown()5084 void MethodVerifier::Shutdown() {
5085   verifier::RegTypeCache::ShutDown();
5086 }
5087 
VisitStaticRoots(RootVisitor * visitor)5088 void MethodVerifier::VisitStaticRoots(RootVisitor* visitor) {
5089   RegTypeCache::VisitStaticRoots(visitor);
5090 }
5091 
VisitRoots(RootVisitor * visitor,const RootInfo & root_info)5092 void MethodVerifier::VisitRoots(RootVisitor* visitor, const RootInfo& root_info) {
5093   reg_types_.VisitRoots(visitor, root_info);
5094 }
5095 
FromClass(const char * descriptor,mirror::Class * klass,bool precise)5096 const RegType& MethodVerifier::FromClass(const char* descriptor,
5097                                          mirror::Class* klass,
5098                                          bool precise) {
5099   DCHECK(klass != nullptr);
5100   if (precise && !klass->IsInstantiable() && !klass->IsPrimitive()) {
5101     Fail(VerifyError::VERIFY_ERROR_NO_CLASS) << "Could not create precise reference for "
5102         << "non-instantiable klass " << descriptor;
5103     precise = false;
5104   }
5105   return reg_types_.FromClass(descriptor, klass, precise);
5106 }
5107 
5108 }  // namespace verifier
5109 }  // namespace art
5110