1 // Copyright 2011 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_X87_CODE_STUBS_X87_H_
6 #define V8_X87_CODE_STUBS_X87_H_
7 
8 namespace v8 {
9 namespace internal {
10 
11 
12 void ArrayNativeCode(MacroAssembler* masm,
13                      bool construct_call,
14                      Label* call_generic_code);
15 
16 
17 class StringHelper : public AllStatic {
18  public:
19   // Generate code for copying characters using the rep movs instruction.
20   // Copies ecx characters from esi to edi. Copying of overlapping regions is
21   // not supported.
22   static void GenerateCopyCharacters(MacroAssembler* masm,
23                                      Register dest,
24                                      Register src,
25                                      Register count,
26                                      Register scratch,
27                                      String::Encoding encoding);
28 
29   // Compares two flat one byte strings and returns result in eax.
30   static void GenerateCompareFlatOneByteStrings(MacroAssembler* masm,
31                                                 Register left, Register right,
32                                                 Register scratch1,
33                                                 Register scratch2,
34                                                 Register scratch3);
35 
36   // Compares two flat one byte strings for equality and returns result in eax.
37   static void GenerateFlatOneByteStringEquals(MacroAssembler* masm,
38                                               Register left, Register right,
39                                               Register scratch1,
40                                               Register scratch2);
41 
42  private:
43   static void GenerateOneByteCharsCompareLoop(
44       MacroAssembler* masm, Register left, Register right, Register length,
45       Register scratch, Label* chars_not_equal,
46       Label::Distance chars_not_equal_near = Label::kFar);
47 
48   DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
49 };
50 
51 
52 class NameDictionaryLookupStub: public PlatformCodeStub {
53  public:
54   enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };
55 
NameDictionaryLookupStub(Isolate * isolate,Register dictionary,Register result,Register index,LookupMode mode)56   NameDictionaryLookupStub(Isolate* isolate, Register dictionary,
57                            Register result, Register index, LookupMode mode)
58       : PlatformCodeStub(isolate) {
59     minor_key_ = DictionaryBits::encode(dictionary.code()) |
60                  ResultBits::encode(result.code()) |
61                  IndexBits::encode(index.code()) | LookupModeBits::encode(mode);
62   }
63 
64   static void GenerateNegativeLookup(MacroAssembler* masm,
65                                      Label* miss,
66                                      Label* done,
67                                      Register properties,
68                                      Handle<Name> name,
69                                      Register r0);
70 
71   static void GeneratePositiveLookup(MacroAssembler* masm,
72                                      Label* miss,
73                                      Label* done,
74                                      Register elements,
75                                      Register name,
76                                      Register r0,
77                                      Register r1);
78 
SometimesSetsUpAFrame()79   bool SometimesSetsUpAFrame() override { return false; }
80 
81  private:
82   static const int kInlinedProbes = 4;
83   static const int kTotalProbes = 20;
84 
85   static const int kCapacityOffset =
86       NameDictionary::kHeaderSize +
87       NameDictionary::kCapacityIndex * kPointerSize;
88 
89   static const int kElementsStartOffset =
90       NameDictionary::kHeaderSize +
91       NameDictionary::kElementsStartIndex * kPointerSize;
92 
dictionary()93   Register dictionary() const {
94     return Register::from_code(DictionaryBits::decode(minor_key_));
95   }
96 
result()97   Register result() const {
98     return Register::from_code(ResultBits::decode(minor_key_));
99   }
100 
index()101   Register index() const {
102     return Register::from_code(IndexBits::decode(minor_key_));
103   }
104 
mode()105   LookupMode mode() const { return LookupModeBits::decode(minor_key_); }
106 
107   class DictionaryBits: public BitField<int, 0, 3> {};
108   class ResultBits: public BitField<int, 3, 3> {};
109   class IndexBits: public BitField<int, 6, 3> {};
110   class LookupModeBits: public BitField<LookupMode, 9, 1> {};
111 
112   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
113   DEFINE_PLATFORM_CODE_STUB(NameDictionaryLookup, PlatformCodeStub);
114 };
115 
116 
117 class RecordWriteStub: public PlatformCodeStub {
118  public:
RecordWriteStub(Isolate * isolate,Register object,Register value,Register address,RememberedSetAction remembered_set_action,SaveFPRegsMode fp_mode)119   RecordWriteStub(Isolate* isolate, Register object, Register value,
120                   Register address, RememberedSetAction remembered_set_action,
121                   SaveFPRegsMode fp_mode)
122       : PlatformCodeStub(isolate),
123         regs_(object,   // An input reg.
124               address,  // An input reg.
125               value) {  // One scratch reg.
126     minor_key_ = ObjectBits::encode(object.code()) |
127                  ValueBits::encode(value.code()) |
128                  AddressBits::encode(address.code()) |
129                  RememberedSetActionBits::encode(remembered_set_action) |
130                  SaveFPRegsModeBits::encode(fp_mode);
131   }
132 
RecordWriteStub(uint32_t key,Isolate * isolate)133   RecordWriteStub(uint32_t key, Isolate* isolate)
134       : PlatformCodeStub(key, isolate), regs_(object(), address(), value()) {}
135 
136   enum Mode {
137     STORE_BUFFER_ONLY,
138     INCREMENTAL,
139     INCREMENTAL_COMPACTION
140   };
141 
SometimesSetsUpAFrame()142   bool SometimesSetsUpAFrame() override { return false; }
143 
144   static const byte kTwoByteNopInstruction = 0x3c;  // Cmpb al, #imm8.
145   static const byte kTwoByteJumpInstruction = 0xeb;  // Jmp #imm8.
146 
147   static const byte kFiveByteNopInstruction = 0x3d;  // Cmpl eax, #imm32.
148   static const byte kFiveByteJumpInstruction = 0xe9;  // Jmp #imm32.
149 
GetMode(Code * stub)150   static Mode GetMode(Code* stub) {
151     byte first_instruction = stub->instruction_start()[0];
152     byte second_instruction = stub->instruction_start()[2];
153 
154     if (first_instruction == kTwoByteJumpInstruction) {
155       return INCREMENTAL;
156     }
157 
158     DCHECK(first_instruction == kTwoByteNopInstruction);
159 
160     if (second_instruction == kFiveByteJumpInstruction) {
161       return INCREMENTAL_COMPACTION;
162     }
163 
164     DCHECK(second_instruction == kFiveByteNopInstruction);
165 
166     return STORE_BUFFER_ONLY;
167   }
168 
Patch(Code * stub,Mode mode)169   static void Patch(Code* stub, Mode mode) {
170     switch (mode) {
171       case STORE_BUFFER_ONLY:
172         DCHECK(GetMode(stub) == INCREMENTAL ||
173                GetMode(stub) == INCREMENTAL_COMPACTION);
174         stub->instruction_start()[0] = kTwoByteNopInstruction;
175         stub->instruction_start()[2] = kFiveByteNopInstruction;
176         break;
177       case INCREMENTAL:
178         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
179         stub->instruction_start()[0] = kTwoByteJumpInstruction;
180         break;
181       case INCREMENTAL_COMPACTION:
182         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
183         stub->instruction_start()[0] = kTwoByteNopInstruction;
184         stub->instruction_start()[2] = kFiveByteJumpInstruction;
185         break;
186     }
187     DCHECK(GetMode(stub) == mode);
188     Assembler::FlushICache(stub->GetIsolate(), stub->instruction_start(), 7);
189   }
190 
191   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
192 
193  private:
194   // This is a helper class for freeing up 3 scratch registers, where the third
195   // is always ecx (needed for shift operations).  The input is two registers
196   // that must be preserved and one scratch register provided by the caller.
197   class RegisterAllocation {
198    public:
RegisterAllocation(Register object,Register address,Register scratch0)199     RegisterAllocation(Register object,
200                        Register address,
201                        Register scratch0)
202         : object_orig_(object),
203           address_orig_(address),
204           scratch0_orig_(scratch0),
205           object_(object),
206           address_(address),
207           scratch0_(scratch0) {
208       DCHECK(!AreAliased(scratch0, object, address, no_reg));
209       scratch1_ = GetRegThatIsNotEcxOr(object_, address_, scratch0_);
210       if (scratch0.is(ecx)) {
211         scratch0_ = GetRegThatIsNotEcxOr(object_, address_, scratch1_);
212       }
213       if (object.is(ecx)) {
214         object_ = GetRegThatIsNotEcxOr(address_, scratch0_, scratch1_);
215       }
216       if (address.is(ecx)) {
217         address_ = GetRegThatIsNotEcxOr(object_, scratch0_, scratch1_);
218       }
219       DCHECK(!AreAliased(scratch0_, object_, address_, ecx));
220     }
221 
Save(MacroAssembler * masm)222     void Save(MacroAssembler* masm) {
223       DCHECK(!address_orig_.is(object_));
224       DCHECK(object_.is(object_orig_) || address_.is(address_orig_));
225       DCHECK(!AreAliased(object_, address_, scratch1_, scratch0_));
226       DCHECK(!AreAliased(object_orig_, address_, scratch1_, scratch0_));
227       DCHECK(!AreAliased(object_, address_orig_, scratch1_, scratch0_));
228       // We don't have to save scratch0_orig_ because it was given to us as
229       // a scratch register.  But if we had to switch to a different reg then
230       // we should save the new scratch0_.
231       if (!scratch0_.is(scratch0_orig_)) masm->push(scratch0_);
232       if (!ecx.is(scratch0_orig_) &&
233           !ecx.is(object_orig_) &&
234           !ecx.is(address_orig_)) {
235         masm->push(ecx);
236       }
237       masm->push(scratch1_);
238       if (!address_.is(address_orig_)) {
239         masm->push(address_);
240         masm->mov(address_, address_orig_);
241       }
242       if (!object_.is(object_orig_)) {
243         masm->push(object_);
244         masm->mov(object_, object_orig_);
245       }
246     }
247 
Restore(MacroAssembler * masm)248     void Restore(MacroAssembler* masm) {
249       // These will have been preserved the entire time, so we just need to move
250       // them back.  Only in one case is the orig_ reg different from the plain
251       // one, since only one of them can alias with ecx.
252       if (!object_.is(object_orig_)) {
253         masm->mov(object_orig_, object_);
254         masm->pop(object_);
255       }
256       if (!address_.is(address_orig_)) {
257         masm->mov(address_orig_, address_);
258         masm->pop(address_);
259       }
260       masm->pop(scratch1_);
261       if (!ecx.is(scratch0_orig_) &&
262           !ecx.is(object_orig_) &&
263           !ecx.is(address_orig_)) {
264         masm->pop(ecx);
265       }
266       if (!scratch0_.is(scratch0_orig_)) masm->pop(scratch0_);
267     }
268 
269     // If we have to call into C then we need to save and restore all caller-
270     // saved registers that were not already preserved.  The caller saved
271     // registers are eax, ecx and edx.  The three scratch registers (incl. ecx)
272     // will be restored by other means so we don't bother pushing them here.
SaveCallerSaveRegisters(MacroAssembler * masm,SaveFPRegsMode mode)273     void SaveCallerSaveRegisters(MacroAssembler* masm, SaveFPRegsMode mode) {
274       if (!scratch0_.is(eax) && !scratch1_.is(eax)) masm->push(eax);
275       if (!scratch0_.is(edx) && !scratch1_.is(edx)) masm->push(edx);
276       if (mode == kSaveFPRegs) {
277         // Save FPU state in m108byte.
278         masm->sub(esp, Immediate(108));
279         masm->fnsave(Operand(esp, 0));
280       }
281     }
282 
RestoreCallerSaveRegisters(MacroAssembler * masm,SaveFPRegsMode mode)283     inline void RestoreCallerSaveRegisters(MacroAssembler* masm,
284                                            SaveFPRegsMode mode) {
285       if (mode == kSaveFPRegs) {
286         // Restore FPU state in m108byte.
287         masm->frstor(Operand(esp, 0));
288         masm->add(esp, Immediate(108));
289       }
290       if (!scratch0_.is(edx) && !scratch1_.is(edx)) masm->pop(edx);
291       if (!scratch0_.is(eax) && !scratch1_.is(eax)) masm->pop(eax);
292     }
293 
object()294     inline Register object() { return object_; }
address()295     inline Register address() { return address_; }
scratch0()296     inline Register scratch0() { return scratch0_; }
scratch1()297     inline Register scratch1() { return scratch1_; }
298 
299    private:
300     Register object_orig_;
301     Register address_orig_;
302     Register scratch0_orig_;
303     Register object_;
304     Register address_;
305     Register scratch0_;
306     Register scratch1_;
307     // Third scratch register is always ecx.
308 
GetRegThatIsNotEcxOr(Register r1,Register r2,Register r3)309     Register GetRegThatIsNotEcxOr(Register r1,
310                                   Register r2,
311                                   Register r3) {
312       for (int i = 0; i < Register::kNumRegisters; i++) {
313         Register candidate = Register::from_code(i);
314         if (candidate.IsAllocatable()) {
315           if (candidate.is(ecx)) continue;
316           if (candidate.is(r1)) continue;
317           if (candidate.is(r2)) continue;
318           if (candidate.is(r3)) continue;
319           return candidate;
320         }
321       }
322       UNREACHABLE();
323       return no_reg;
324     }
325     friend class RecordWriteStub;
326   };
327 
328   enum OnNoNeedToInformIncrementalMarker {
329     kReturnOnNoNeedToInformIncrementalMarker,
330     kUpdateRememberedSetOnNoNeedToInformIncrementalMarker
331   };
332 
MajorKey()333   inline Major MajorKey() const final { return RecordWrite; }
334 
335   void Generate(MacroAssembler* masm) override;
336   void GenerateIncremental(MacroAssembler* masm, Mode mode);
337   void CheckNeedsToInformIncrementalMarker(
338       MacroAssembler* masm,
339       OnNoNeedToInformIncrementalMarker on_no_need,
340       Mode mode);
341   void InformIncrementalMarker(MacroAssembler* masm);
342 
Activate(Code * code)343   void Activate(Code* code) override {
344     code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
345   }
346 
object()347   Register object() const {
348     return Register::from_code(ObjectBits::decode(minor_key_));
349   }
350 
value()351   Register value() const {
352     return Register::from_code(ValueBits::decode(minor_key_));
353   }
354 
address()355   Register address() const {
356     return Register::from_code(AddressBits::decode(minor_key_));
357   }
358 
remembered_set_action()359   RememberedSetAction remembered_set_action() const {
360     return RememberedSetActionBits::decode(minor_key_);
361   }
362 
save_fp_regs_mode()363   SaveFPRegsMode save_fp_regs_mode() const {
364     return SaveFPRegsModeBits::decode(minor_key_);
365   }
366 
367   class ObjectBits: public BitField<int, 0, 3> {};
368   class ValueBits: public BitField<int, 3, 3> {};
369   class AddressBits: public BitField<int, 6, 3> {};
370   class RememberedSetActionBits: public BitField<RememberedSetAction, 9, 1> {};
371   class SaveFPRegsModeBits : public BitField<SaveFPRegsMode, 10, 1> {};
372 
373   RegisterAllocation regs_;
374 
375   DISALLOW_COPY_AND_ASSIGN(RecordWriteStub);
376 };
377 
378 
379 }  // namespace internal
380 }  // namespace v8
381 
382 #endif  // V8_X87_CODE_STUBS_X87_H_
383