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 "stack.h"
18 
19 #include "arch/context.h"
20 #include "base/hex_dump.h"
21 #include "mirror/art_method-inl.h"
22 #include "mirror/class-inl.h"
23 #include "mirror/object.h"
24 #include "mirror/object-inl.h"
25 #include "mirror/object_array-inl.h"
26 #include "quick/quick_method_frame_info.h"
27 #include "runtime.h"
28 #include "thread.h"
29 #include "thread_list.h"
30 #include "throw_location.h"
31 #include "verify_object-inl.h"
32 #include "vmap_table.h"
33 
34 namespace art {
35 
GetThisObject() const36 mirror::Object* ShadowFrame::GetThisObject() const {
37   mirror::ArtMethod* m = GetMethod();
38   if (m->IsStatic()) {
39     return NULL;
40   } else if (m->IsNative()) {
41     return GetVRegReference(0);
42   } else {
43     const DexFile::CodeItem* code_item = m->GetCodeItem();
44     CHECK(code_item != NULL) << PrettyMethod(m);
45     uint16_t reg = code_item->registers_size_ - code_item->ins_size_;
46     return GetVRegReference(reg);
47   }
48 }
49 
GetThisObject(uint16_t num_ins) const50 mirror::Object* ShadowFrame::GetThisObject(uint16_t num_ins) const {
51   mirror::ArtMethod* m = GetMethod();
52   if (m->IsStatic()) {
53     return NULL;
54   } else {
55     return GetVRegReference(NumberOfVRegs() - num_ins);
56   }
57 }
58 
GetCurrentLocationForThrow() const59 ThrowLocation ShadowFrame::GetCurrentLocationForThrow() const {
60   return ThrowLocation(GetThisObject(), GetMethod(), GetDexPC());
61 }
62 
NumJniShadowFrameReferences() const63 size_t ManagedStack::NumJniShadowFrameReferences() const {
64   size_t count = 0;
65   for (const ManagedStack* current_fragment = this; current_fragment != NULL;
66        current_fragment = current_fragment->GetLink()) {
67     for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != NULL;
68          current_frame = current_frame->GetLink()) {
69       if (current_frame->GetMethod()->IsNative()) {
70         // The JNI ShadowFrame only contains references. (For indirect reference.)
71         count += current_frame->NumberOfVRegs();
72       }
73     }
74   }
75   return count;
76 }
77 
ShadowFramesContain(StackReference<mirror::Object> * shadow_frame_entry) const78 bool ManagedStack::ShadowFramesContain(StackReference<mirror::Object>* shadow_frame_entry) const {
79   for (const ManagedStack* current_fragment = this; current_fragment != NULL;
80        current_fragment = current_fragment->GetLink()) {
81     for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != NULL;
82          current_frame = current_frame->GetLink()) {
83       if (current_frame->Contains(shadow_frame_entry)) {
84         return true;
85       }
86     }
87   }
88   return false;
89 }
90 
StackVisitor(Thread * thread,Context * context)91 StackVisitor::StackVisitor(Thread* thread, Context* context)
92     : thread_(thread), cur_shadow_frame_(NULL),
93       cur_quick_frame_(NULL), cur_quick_frame_pc_(0), num_frames_(0), cur_depth_(0),
94       context_(context) {
95   DCHECK(thread == Thread::Current() || thread->IsSuspended()) << *thread;
96 }
97 
StackVisitor(Thread * thread,Context * context,size_t num_frames)98 StackVisitor::StackVisitor(Thread* thread, Context* context, size_t num_frames)
99     : thread_(thread), cur_shadow_frame_(NULL),
100       cur_quick_frame_(NULL), cur_quick_frame_pc_(0), num_frames_(num_frames), cur_depth_(0),
101       context_(context) {
102   DCHECK(thread == Thread::Current() || thread->IsSuspended()) << *thread;
103 }
104 
GetDexPc(bool abort_on_failure) const105 uint32_t StackVisitor::GetDexPc(bool abort_on_failure) const {
106   if (cur_shadow_frame_ != NULL) {
107     return cur_shadow_frame_->GetDexPC();
108   } else if (cur_quick_frame_ != NULL) {
109     return GetMethod()->ToDexPc(cur_quick_frame_pc_, abort_on_failure);
110   } else {
111     return 0;
112   }
113 }
114 
115 extern "C" mirror::Object* artQuickGetProxyThisObject(StackReference<mirror::ArtMethod>* sp)
116     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
117 
GetThisObject() const118 mirror::Object* StackVisitor::GetThisObject() const {
119   mirror::ArtMethod* m = GetMethod();
120   if (m->IsStatic()) {
121     return NULL;
122   } else if (m->IsNative()) {
123     if (cur_quick_frame_ != NULL) {
124       HandleScope* hs = reinterpret_cast<HandleScope*>(
125           reinterpret_cast<char*>(cur_quick_frame_) + m->GetHandleScopeOffsetInBytes().SizeValue());
126       return hs->GetReference(0);
127     } else {
128       return cur_shadow_frame_->GetVRegReference(0);
129     }
130   } else if (m->IsProxyMethod()) {
131     if (cur_quick_frame_ != nullptr) {
132       return artQuickGetProxyThisObject(cur_quick_frame_);
133     } else {
134       return cur_shadow_frame_->GetVRegReference(0);
135     }
136   } else {
137     const DexFile::CodeItem* code_item = m->GetCodeItem();
138     if (code_item == NULL) {
139       UNIMPLEMENTED(ERROR) << "Failed to determine this object of abstract or proxy method: "
140           << PrettyMethod(m);
141       return nullptr;
142     } else {
143       uint16_t reg = code_item->registers_size_ - code_item->ins_size_;
144       return reinterpret_cast<mirror::Object*>(GetVReg(m, reg, kReferenceVReg));
145     }
146   }
147 }
148 
GetNativePcOffset() const149 size_t StackVisitor::GetNativePcOffset() const {
150   DCHECK(!IsShadowFrame());
151   return GetMethod()->NativePcOffset(cur_quick_frame_pc_);
152 }
153 
GetVReg(mirror::ArtMethod * m,uint16_t vreg,VRegKind kind,uint32_t * val) const154 bool StackVisitor::GetVReg(mirror::ArtMethod* m, uint16_t vreg, VRegKind kind,
155                            uint32_t* val) const {
156   if (cur_quick_frame_ != nullptr) {
157     DCHECK(context_ != nullptr);  // You can't reliably read registers without a context.
158     DCHECK(m == GetMethod());
159     const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
160     DCHECK(code_pointer != nullptr);
161     const VmapTable vmap_table(m->GetVmapTable(code_pointer, sizeof(void*)));
162     QuickMethodFrameInfo frame_info = m->GetQuickFrameInfo(code_pointer);
163     uint32_t vmap_offset;
164     // TODO: IsInContext stops before spotting floating point registers.
165     if (vmap_table.IsInContext(vreg, kind, &vmap_offset)) {
166       bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
167       uint32_t spill_mask = is_float ? frame_info.FpSpillMask() : frame_info.CoreSpillMask();
168       uint32_t reg = vmap_table.ComputeRegister(spill_mask, vmap_offset, kind);
169       uintptr_t ptr_val;
170       bool success = is_float ? GetFPR(reg, &ptr_val) : GetGPR(reg, &ptr_val);
171       if (!success) {
172         return false;
173       }
174       bool target64 = Is64BitInstructionSet(kRuntimeISA);
175       if (target64) {
176         bool wide_lo = (kind == kLongLoVReg) || (kind == kDoubleLoVReg);
177         bool wide_hi = (kind == kLongHiVReg) || (kind == kDoubleHiVReg);
178         int64_t value_long = static_cast<int64_t>(ptr_val);
179         if (wide_lo) {
180           ptr_val = static_cast<uintptr_t>(value_long & 0xFFFFFFFF);
181         } else if (wide_hi) {
182           ptr_val = static_cast<uintptr_t>(value_long >> 32);
183         }
184       }
185       *val = ptr_val;
186       return true;
187     } else {
188       const DexFile::CodeItem* code_item = m->GetCodeItem();
189       DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be NULL or how would we compile
190                                                         // its instructions?
191       *val = *GetVRegAddr(cur_quick_frame_, code_item, frame_info.CoreSpillMask(),
192                           frame_info.FpSpillMask(), frame_info.FrameSizeInBytes(), vreg);
193       return true;
194     }
195   } else {
196     *val = cur_shadow_frame_->GetVReg(vreg);
197     return true;
198   }
199 }
200 
GetVRegPair(mirror::ArtMethod * m,uint16_t vreg,VRegKind kind_lo,VRegKind kind_hi,uint64_t * val) const201 bool StackVisitor::GetVRegPair(mirror::ArtMethod* m, uint16_t vreg, VRegKind kind_lo,
202                                VRegKind kind_hi, uint64_t* val) const {
203   if (kind_lo == kLongLoVReg) {
204     DCHECK_EQ(kind_hi, kLongHiVReg);
205   } else if (kind_lo == kDoubleLoVReg) {
206     DCHECK_EQ(kind_hi, kDoubleHiVReg);
207   } else {
208     LOG(FATAL) << "Expected long or double: kind_lo=" << kind_lo << ", kind_hi=" << kind_hi;
209   }
210   if (cur_quick_frame_ != nullptr) {
211     DCHECK(context_ != nullptr);  // You can't reliably read registers without a context.
212     DCHECK(m == GetMethod());
213     const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
214     DCHECK(code_pointer != nullptr);
215     const VmapTable vmap_table(m->GetVmapTable(code_pointer, sizeof(void*)));
216     QuickMethodFrameInfo frame_info = m->GetQuickFrameInfo(code_pointer);
217     uint32_t vmap_offset_lo, vmap_offset_hi;
218     // TODO: IsInContext stops before spotting floating point registers.
219     if (vmap_table.IsInContext(vreg, kind_lo, &vmap_offset_lo) &&
220         vmap_table.IsInContext(vreg + 1, kind_hi, &vmap_offset_hi)) {
221       bool is_float = (kind_lo == kDoubleLoVReg);
222       uint32_t spill_mask = is_float ? frame_info.FpSpillMask() : frame_info.CoreSpillMask();
223       uint32_t reg_lo = vmap_table.ComputeRegister(spill_mask, vmap_offset_lo, kind_lo);
224       uint32_t reg_hi = vmap_table.ComputeRegister(spill_mask, vmap_offset_hi, kind_hi);
225       uintptr_t ptr_val_lo, ptr_val_hi;
226       bool success = is_float ? GetFPR(reg_lo, &ptr_val_lo) : GetGPR(reg_lo, &ptr_val_lo);
227       success &= is_float ? GetFPR(reg_hi, &ptr_val_hi) : GetGPR(reg_hi, &ptr_val_hi);
228       if (!success) {
229         return false;
230       }
231       bool target64 = Is64BitInstructionSet(kRuntimeISA);
232       if (target64) {
233         int64_t value_long_lo = static_cast<int64_t>(ptr_val_lo);
234         int64_t value_long_hi = static_cast<int64_t>(ptr_val_hi);
235         ptr_val_lo = static_cast<uintptr_t>(value_long_lo & 0xFFFFFFFF);
236         ptr_val_hi = static_cast<uintptr_t>(value_long_hi >> 32);
237       }
238       *val = (static_cast<uint64_t>(ptr_val_hi) << 32) | static_cast<uint32_t>(ptr_val_lo);
239       return true;
240     } else {
241       const DexFile::CodeItem* code_item = m->GetCodeItem();
242       DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be NULL or how would we compile
243                                                         // its instructions?
244       uint32_t* addr = GetVRegAddr(cur_quick_frame_, code_item, frame_info.CoreSpillMask(),
245                                    frame_info.FpSpillMask(), frame_info.FrameSizeInBytes(), vreg);
246       *val = *reinterpret_cast<uint64_t*>(addr);
247       return true;
248     }
249   } else {
250     *val = cur_shadow_frame_->GetVRegLong(vreg);
251     return true;
252   }
253 }
254 
SetVReg(mirror::ArtMethod * m,uint16_t vreg,uint32_t new_value,VRegKind kind)255 bool StackVisitor::SetVReg(mirror::ArtMethod* m, uint16_t vreg, uint32_t new_value,
256                            VRegKind kind) {
257   if (cur_quick_frame_ != nullptr) {
258     DCHECK(context_ != nullptr);  // You can't reliably write registers without a context.
259     DCHECK(m == GetMethod());
260     const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
261     DCHECK(code_pointer != nullptr);
262     const VmapTable vmap_table(m->GetVmapTable(code_pointer, sizeof(void*)));
263     QuickMethodFrameInfo frame_info = m->GetQuickFrameInfo(code_pointer);
264     uint32_t vmap_offset;
265     // TODO: IsInContext stops before spotting floating point registers.
266     if (vmap_table.IsInContext(vreg, kind, &vmap_offset)) {
267       bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
268       uint32_t spill_mask = is_float ? frame_info.FpSpillMask() : frame_info.CoreSpillMask();
269       const uint32_t reg = vmap_table.ComputeRegister(spill_mask, vmap_offset, kind);
270       bool target64 = Is64BitInstructionSet(kRuntimeISA);
271       // Deal with 32 or 64-bit wide registers in a way that builds on all targets.
272       if (target64) {
273         bool wide_lo = (kind == kLongLoVReg) || (kind == kDoubleLoVReg);
274         bool wide_hi = (kind == kLongHiVReg) || (kind == kDoubleHiVReg);
275         if (wide_lo || wide_hi) {
276           uintptr_t old_reg_val;
277           bool success = is_float ? GetFPR(reg, &old_reg_val) : GetGPR(reg, &old_reg_val);
278           if (!success) {
279             return false;
280           }
281           uint64_t new_vreg_portion = static_cast<uint64_t>(new_value);
282           uint64_t old_reg_val_as_wide = static_cast<uint64_t>(old_reg_val);
283           uint64_t mask = 0xffffffff;
284           if (wide_lo) {
285             mask = mask << 32;
286           } else {
287             new_vreg_portion = new_vreg_portion << 32;
288           }
289           new_value = static_cast<uintptr_t>((old_reg_val_as_wide & mask) | new_vreg_portion);
290         }
291       }
292       if (is_float) {
293         return SetFPR(reg, new_value);
294       } else {
295         return SetGPR(reg, new_value);
296       }
297     } else {
298       const DexFile::CodeItem* code_item = m->GetCodeItem();
299       DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be NULL or how would we compile
300                                                         // its instructions?
301       uint32_t* addr = GetVRegAddr(cur_quick_frame_, code_item, frame_info.CoreSpillMask(),
302                                    frame_info.FpSpillMask(), frame_info.FrameSizeInBytes(), vreg);
303       *addr = new_value;
304       return true;
305     }
306   } else {
307     cur_shadow_frame_->SetVReg(vreg, new_value);
308     return true;
309   }
310 }
311 
SetVRegPair(mirror::ArtMethod * m,uint16_t vreg,uint64_t new_value,VRegKind kind_lo,VRegKind kind_hi)312 bool StackVisitor::SetVRegPair(mirror::ArtMethod* m, uint16_t vreg, uint64_t new_value,
313                                VRegKind kind_lo, VRegKind kind_hi) {
314   if (kind_lo == kLongLoVReg) {
315     DCHECK_EQ(kind_hi, kLongHiVReg);
316   } else if (kind_lo == kDoubleLoVReg) {
317     DCHECK_EQ(kind_hi, kDoubleHiVReg);
318   } else {
319     LOG(FATAL) << "Expected long or double: kind_lo=" << kind_lo << ", kind_hi=" << kind_hi;
320   }
321   if (cur_quick_frame_ != nullptr) {
322     DCHECK(context_ != nullptr);  // You can't reliably write registers without a context.
323     DCHECK(m == GetMethod());
324     const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
325     DCHECK(code_pointer != nullptr);
326     const VmapTable vmap_table(m->GetVmapTable(code_pointer, sizeof(void*)));
327     QuickMethodFrameInfo frame_info = m->GetQuickFrameInfo(code_pointer);
328     uint32_t vmap_offset_lo, vmap_offset_hi;
329     // TODO: IsInContext stops before spotting floating point registers.
330     if (vmap_table.IsInContext(vreg, kind_lo, &vmap_offset_lo) &&
331         vmap_table.IsInContext(vreg + 1, kind_hi, &vmap_offset_hi)) {
332       bool is_float = (kind_lo == kDoubleLoVReg);
333       uint32_t spill_mask = is_float ? frame_info.FpSpillMask() : frame_info.CoreSpillMask();
334       uint32_t reg_lo = vmap_table.ComputeRegister(spill_mask, vmap_offset_lo, kind_lo);
335       uint32_t reg_hi = vmap_table.ComputeRegister(spill_mask, vmap_offset_hi, kind_hi);
336       uintptr_t new_value_lo = static_cast<uintptr_t>(new_value & 0xFFFFFFFF);
337       uintptr_t new_value_hi = static_cast<uintptr_t>(new_value >> 32);
338       bool target64 = Is64BitInstructionSet(kRuntimeISA);
339       // Deal with 32 or 64-bit wide registers in a way that builds on all targets.
340       if (target64) {
341         uintptr_t old_reg_val_lo, old_reg_val_hi;
342         bool success = is_float ? GetFPR(reg_lo, &old_reg_val_lo) : GetGPR(reg_lo, &old_reg_val_lo);
343         success &= is_float ? GetFPR(reg_hi, &old_reg_val_hi) : GetGPR(reg_hi, &old_reg_val_hi);
344         if (!success) {
345           return false;
346         }
347         uint64_t new_vreg_portion_lo = static_cast<uint64_t>(new_value_lo);
348         uint64_t new_vreg_portion_hi = static_cast<uint64_t>(new_value_hi) << 32;
349         uint64_t old_reg_val_lo_as_wide = static_cast<uint64_t>(old_reg_val_lo);
350         uint64_t old_reg_val_hi_as_wide = static_cast<uint64_t>(old_reg_val_hi);
351         uint64_t mask_lo = static_cast<uint64_t>(0xffffffff) << 32;
352         uint64_t mask_hi = 0xffffffff;
353         new_value_lo = static_cast<uintptr_t>((old_reg_val_lo_as_wide & mask_lo) | new_vreg_portion_lo);
354         new_value_hi = static_cast<uintptr_t>((old_reg_val_hi_as_wide & mask_hi) | new_vreg_portion_hi);
355       }
356       bool success = is_float ? SetFPR(reg_lo, new_value_lo) : SetGPR(reg_lo, new_value_lo);
357       success &= is_float ? SetFPR(reg_hi, new_value_hi) : SetGPR(reg_hi, new_value_hi);
358       return success;
359     } else {
360       const DexFile::CodeItem* code_item = m->GetCodeItem();
361       DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be NULL or how would we compile
362                                                         // its instructions?
363       uint32_t* addr = GetVRegAddr(cur_quick_frame_, code_item, frame_info.CoreSpillMask(),
364                                    frame_info.FpSpillMask(), frame_info.FrameSizeInBytes(), vreg);
365       *reinterpret_cast<uint64_t*>(addr) = new_value;
366       return true;
367     }
368   } else {
369     cur_shadow_frame_->SetVRegLong(vreg, new_value);
370     return true;
371   }
372 }
373 
GetGPRAddress(uint32_t reg) const374 uintptr_t* StackVisitor::GetGPRAddress(uint32_t reg) const {
375   DCHECK(cur_quick_frame_ != NULL) << "This is a quick frame routine";
376   return context_->GetGPRAddress(reg);
377 }
378 
GetGPR(uint32_t reg,uintptr_t * val) const379 bool StackVisitor::GetGPR(uint32_t reg, uintptr_t* val) const {
380   DCHECK(cur_quick_frame_ != NULL) << "This is a quick frame routine";
381   return context_->GetGPR(reg, val);
382 }
383 
SetGPR(uint32_t reg,uintptr_t value)384 bool StackVisitor::SetGPR(uint32_t reg, uintptr_t value) {
385   DCHECK(cur_quick_frame_ != NULL) << "This is a quick frame routine";
386   return context_->SetGPR(reg, value);
387 }
388 
GetFPR(uint32_t reg,uintptr_t * val) const389 bool StackVisitor::GetFPR(uint32_t reg, uintptr_t* val) const {
390   DCHECK(cur_quick_frame_ != NULL) << "This is a quick frame routine";
391   return context_->GetFPR(reg, val);
392 }
393 
SetFPR(uint32_t reg,uintptr_t value)394 bool StackVisitor::SetFPR(uint32_t reg, uintptr_t value) {
395   DCHECK(cur_quick_frame_ != NULL) << "This is a quick frame routine";
396   return context_->SetFPR(reg, value);
397 }
398 
GetReturnPc() const399 uintptr_t StackVisitor::GetReturnPc() const {
400   byte* sp = reinterpret_cast<byte*>(GetCurrentQuickFrame());
401   DCHECK(sp != NULL);
402   byte* pc_addr = sp + GetMethod()->GetReturnPcOffsetInBytes();
403   return *reinterpret_cast<uintptr_t*>(pc_addr);
404 }
405 
SetReturnPc(uintptr_t new_ret_pc)406 void StackVisitor::SetReturnPc(uintptr_t new_ret_pc) {
407   byte* sp = reinterpret_cast<byte*>(GetCurrentQuickFrame());
408   CHECK(sp != NULL);
409   byte* pc_addr = sp + GetMethod()->GetReturnPcOffsetInBytes();
410   *reinterpret_cast<uintptr_t*>(pc_addr) = new_ret_pc;
411 }
412 
ComputeNumFrames(Thread * thread)413 size_t StackVisitor::ComputeNumFrames(Thread* thread) {
414   struct NumFramesVisitor : public StackVisitor {
415     explicit NumFramesVisitor(Thread* thread)
416         : StackVisitor(thread, NULL), frames(0) {}
417 
418     bool VisitFrame() OVERRIDE {
419       frames++;
420       return true;
421     }
422 
423     size_t frames;
424   };
425   NumFramesVisitor visitor(thread);
426   visitor.WalkStack(true);
427   return visitor.frames;
428 }
429 
GetNextMethodAndDexPc(mirror::ArtMethod ** next_method,uint32_t * next_dex_pc)430 bool StackVisitor::GetNextMethodAndDexPc(mirror::ArtMethod** next_method, uint32_t* next_dex_pc) {
431   struct HasMoreFramesVisitor : public StackVisitor {
432     explicit HasMoreFramesVisitor(Thread* thread, size_t num_frames, size_t frame_height)
433         : StackVisitor(thread, nullptr, num_frames), frame_height_(frame_height),
434           found_frame_(false), has_more_frames_(false), next_method_(nullptr), next_dex_pc_(0) {
435     }
436 
437     bool VisitFrame() OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
438       if (found_frame_) {
439         mirror::ArtMethod* method = GetMethod();
440         if (method != nullptr && !method->IsRuntimeMethod()) {
441           has_more_frames_ = true;
442           next_method_ = method;
443           next_dex_pc_ = GetDexPc();
444           return false;  // End stack walk once next method is found.
445         }
446       } else if (GetFrameHeight() == frame_height_) {
447         found_frame_ = true;
448       }
449       return true;
450     }
451 
452     size_t frame_height_;
453     bool found_frame_;
454     bool has_more_frames_;
455     mirror::ArtMethod* next_method_;
456     uint32_t next_dex_pc_;
457   };
458   HasMoreFramesVisitor visitor(thread_, GetNumFrames(), GetFrameHeight());
459   visitor.WalkStack(true);
460   *next_method = visitor.next_method_;
461   *next_dex_pc = visitor.next_dex_pc_;
462   return visitor.has_more_frames_;
463 }
464 
DescribeStack(Thread * thread)465 void StackVisitor::DescribeStack(Thread* thread) {
466   struct DescribeStackVisitor : public StackVisitor {
467     explicit DescribeStackVisitor(Thread* thread)
468         : StackVisitor(thread, NULL) {}
469 
470     bool VisitFrame() OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
471       LOG(INFO) << "Frame Id=" << GetFrameId() << " " << DescribeLocation();
472       return true;
473     }
474   };
475   DescribeStackVisitor visitor(thread);
476   visitor.WalkStack(true);
477 }
478 
DescribeLocation() const479 std::string StackVisitor::DescribeLocation() const {
480   std::string result("Visiting method '");
481   mirror::ArtMethod* m = GetMethod();
482   if (m == NULL) {
483     return "upcall";
484   }
485   result += PrettyMethod(m);
486   result += StringPrintf("' at dex PC 0x%04x", GetDexPc());
487   if (!IsShadowFrame()) {
488     result += StringPrintf(" (native PC %p)", reinterpret_cast<void*>(GetCurrentQuickFramePc()));
489   }
490   return result;
491 }
492 
GetInstrumentationStackFrame(Thread * thread,uint32_t depth)493 static instrumentation::InstrumentationStackFrame& GetInstrumentationStackFrame(Thread* thread,
494                                                                                 uint32_t depth) {
495   CHECK_LT(depth, thread->GetInstrumentationStack()->size());
496   return thread->GetInstrumentationStack()->at(depth);
497 }
498 
SanityCheckFrame() const499 void StackVisitor::SanityCheckFrame() const {
500   if (kIsDebugBuild) {
501     mirror::ArtMethod* method = GetMethod();
502     CHECK_EQ(method->GetClass(), mirror::ArtMethod::GetJavaLangReflectArtMethod());
503     if (cur_quick_frame_ != nullptr) {
504       method->AssertPcIsWithinQuickCode(cur_quick_frame_pc_);
505       // Frame sanity.
506       size_t frame_size = method->GetFrameSizeInBytes();
507       CHECK_NE(frame_size, 0u);
508       // A rough guess at an upper size we expect to see for a frame.
509       // 256 registers
510       // 2 words HandleScope overhead
511       // 3+3 register spills
512       // TODO: this seems architecture specific for the case of JNI frames.
513       // TODO: 083-compiler-regressions ManyFloatArgs shows this estimate is wrong.
514       // const size_t kMaxExpectedFrameSize = (256 + 2 + 3 + 3) * sizeof(word);
515       const size_t kMaxExpectedFrameSize = 2 * KB;
516       CHECK_LE(frame_size, kMaxExpectedFrameSize);
517       size_t return_pc_offset = method->GetReturnPcOffsetInBytes();
518       CHECK_LT(return_pc_offset, frame_size);
519     }
520   }
521 }
522 
WalkStack(bool include_transitions)523 void StackVisitor::WalkStack(bool include_transitions) {
524   DCHECK(thread_ == Thread::Current() || thread_->IsSuspended());
525   CHECK_EQ(cur_depth_, 0U);
526   bool exit_stubs_installed = Runtime::Current()->GetInstrumentation()->AreExitStubsInstalled();
527   uint32_t instrumentation_stack_depth = 0;
528 
529   for (const ManagedStack* current_fragment = thread_->GetManagedStack(); current_fragment != NULL;
530        current_fragment = current_fragment->GetLink()) {
531     cur_shadow_frame_ = current_fragment->GetTopShadowFrame();
532     cur_quick_frame_ = current_fragment->GetTopQuickFrame();
533     cur_quick_frame_pc_ = current_fragment->GetTopQuickFramePc();
534 
535     if (cur_quick_frame_ != NULL) {  // Handle quick stack frames.
536       // Can't be both a shadow and a quick fragment.
537       DCHECK(current_fragment->GetTopShadowFrame() == NULL);
538       mirror::ArtMethod* method = cur_quick_frame_->AsMirrorPtr();
539       while (method != NULL) {
540         SanityCheckFrame();
541         bool should_continue = VisitFrame();
542         if (UNLIKELY(!should_continue)) {
543           return;
544         }
545 
546         if (context_ != NULL) {
547           context_->FillCalleeSaves(*this);
548         }
549         size_t frame_size = method->GetFrameSizeInBytes();
550         // Compute PC for next stack frame from return PC.
551         size_t return_pc_offset = method->GetReturnPcOffsetInBytes(frame_size);
552         byte* return_pc_addr = reinterpret_cast<byte*>(cur_quick_frame_) + return_pc_offset;
553         uintptr_t return_pc = *reinterpret_cast<uintptr_t*>(return_pc_addr);
554         if (UNLIKELY(exit_stubs_installed)) {
555           // While profiling, the return pc is restored from the side stack, except when walking
556           // the stack for an exception where the side stack will be unwound in VisitFrame.
557           if (GetQuickInstrumentationExitPc() == return_pc) {
558             const instrumentation::InstrumentationStackFrame& instrumentation_frame =
559                 GetInstrumentationStackFrame(thread_, instrumentation_stack_depth);
560             instrumentation_stack_depth++;
561             if (GetMethod() == Runtime::Current()->GetCalleeSaveMethod(Runtime::kSaveAll)) {
562               // Skip runtime save all callee frames which are used to deliver exceptions.
563             } else if (instrumentation_frame.interpreter_entry_) {
564               mirror::ArtMethod* callee = Runtime::Current()->GetCalleeSaveMethod(Runtime::kRefsAndArgs);
565               CHECK_EQ(GetMethod(), callee) << "Expected: " << PrettyMethod(callee) << " Found: "
566                                             << PrettyMethod(GetMethod());
567             } else if (instrumentation_frame.method_ != GetMethod()) {
568               LOG(FATAL)  << "Expected: " << PrettyMethod(instrumentation_frame.method_)
569                           << " Found: " << PrettyMethod(GetMethod());
570             }
571             if (num_frames_ != 0) {
572               // Check agreement of frame Ids only if num_frames_ is computed to avoid infinite
573               // recursion.
574               CHECK(instrumentation_frame.frame_id_ == GetFrameId())
575                     << "Expected: " << instrumentation_frame.frame_id_
576                     << " Found: " << GetFrameId();
577             }
578             return_pc = instrumentation_frame.return_pc_;
579           }
580         }
581         cur_quick_frame_pc_ = return_pc;
582         byte* next_frame = reinterpret_cast<byte*>(cur_quick_frame_) + frame_size;
583         cur_quick_frame_ = reinterpret_cast<StackReference<mirror::ArtMethod>*>(next_frame);
584         cur_depth_++;
585         method = cur_quick_frame_->AsMirrorPtr();
586       }
587     } else if (cur_shadow_frame_ != NULL) {
588       do {
589         SanityCheckFrame();
590         bool should_continue = VisitFrame();
591         if (UNLIKELY(!should_continue)) {
592           return;
593         }
594         cur_depth_++;
595         cur_shadow_frame_ = cur_shadow_frame_->GetLink();
596       } while (cur_shadow_frame_ != NULL);
597     }
598     if (include_transitions) {
599       bool should_continue = VisitFrame();
600       if (!should_continue) {
601         return;
602       }
603     }
604     cur_depth_++;
605   }
606   if (num_frames_ != 0) {
607     CHECK_EQ(cur_depth_, num_frames_);
608   }
609 }
610 
Describe(std::ostream & os) const611 void JavaFrameRootInfo::Describe(std::ostream& os) const {
612   const StackVisitor* visitor = stack_visitor_;
613   CHECK(visitor != nullptr);
614   os << "Type=" << GetType() << " thread_id=" << GetThreadId() << " location=" <<
615       visitor->DescribeLocation() << " vreg=" << vreg_;
616 }
617 
618 }  // namespace art
619