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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_IA32_CODE_STUBS_IA32_H_
6 #define V8_IA32_CODE_STUBS_IA32_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   // Compares two flat one byte strings and returns result in eax.
20   static void GenerateCompareFlatOneByteStrings(MacroAssembler* masm,
21                                                 Register left, Register right,
22                                                 Register scratch1,
23                                                 Register scratch2,
24                                                 Register scratch3);
25 
26   // Compares two flat one byte strings for equality and returns result in eax.
27   static void GenerateFlatOneByteStringEquals(MacroAssembler* masm,
28                                               Register left, Register right,
29                                               Register scratch1,
30                                               Register scratch2);
31 
32  private:
33   static void GenerateOneByteCharsCompareLoop(
34       MacroAssembler* masm, Register left, Register right, Register length,
35       Register scratch, Label* chars_not_equal,
36       Label::Distance chars_not_equal_near = Label::kFar);
37 
38   DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
39 };
40 
41 
42 class NameDictionaryLookupStub: public PlatformCodeStub {
43  public:
44   enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };
45 
NameDictionaryLookupStub(Isolate * isolate,Register dictionary,Register result,Register index,LookupMode mode)46   NameDictionaryLookupStub(Isolate* isolate, Register dictionary,
47                            Register result, Register index, LookupMode mode)
48       : PlatformCodeStub(isolate) {
49     minor_key_ = DictionaryBits::encode(dictionary.code()) |
50                  ResultBits::encode(result.code()) |
51                  IndexBits::encode(index.code()) | LookupModeBits::encode(mode);
52   }
53 
54   static void GenerateNegativeLookup(MacroAssembler* masm,
55                                      Label* miss,
56                                      Label* done,
57                                      Register properties,
58                                      Handle<Name> name,
59                                      Register r0);
60 
SometimesSetsUpAFrame()61   bool SometimesSetsUpAFrame() override { return false; }
62 
63  private:
64   static const int kInlinedProbes = 4;
65   static const int kTotalProbes = 20;
66 
67   static const int kCapacityOffset =
68       NameDictionary::kHeaderSize +
69       NameDictionary::kCapacityIndex * kPointerSize;
70 
71   static const int kElementsStartOffset =
72       NameDictionary::kHeaderSize +
73       NameDictionary::kElementsStartIndex * kPointerSize;
74 
dictionary()75   Register dictionary() const {
76     return Register::from_code(DictionaryBits::decode(minor_key_));
77   }
78 
result()79   Register result() const {
80     return Register::from_code(ResultBits::decode(minor_key_));
81   }
82 
index()83   Register index() const {
84     return Register::from_code(IndexBits::decode(minor_key_));
85   }
86 
mode()87   LookupMode mode() const { return LookupModeBits::decode(minor_key_); }
88 
89   class DictionaryBits: public BitField<int, 0, 3> {};
90   class ResultBits: public BitField<int, 3, 3> {};
91   class IndexBits: public BitField<int, 6, 3> {};
92   class LookupModeBits: public BitField<LookupMode, 9, 1> {};
93 
94   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
95   DEFINE_PLATFORM_CODE_STUB(NameDictionaryLookup, PlatformCodeStub);
96 };
97 
98 
99 class RecordWriteStub: public PlatformCodeStub {
100  public:
RecordWriteStub(Isolate * isolate,Register object,Register value,Register address,RememberedSetAction remembered_set_action,SaveFPRegsMode fp_mode)101   RecordWriteStub(Isolate* isolate,
102                   Register object,
103                   Register value,
104                   Register address,
105                   RememberedSetAction remembered_set_action,
106                   SaveFPRegsMode fp_mode)
107       : PlatformCodeStub(isolate),
108         regs_(object,   // An input reg.
109               address,  // An input reg.
110               value) {  // One scratch reg.
111     minor_key_ = ObjectBits::encode(object.code()) |
112                  ValueBits::encode(value.code()) |
113                  AddressBits::encode(address.code()) |
114                  RememberedSetActionBits::encode(remembered_set_action) |
115                  SaveFPRegsModeBits::encode(fp_mode);
116   }
117 
RecordWriteStub(uint32_t key,Isolate * isolate)118   RecordWriteStub(uint32_t key, Isolate* isolate)
119       : PlatformCodeStub(key, isolate), regs_(object(), address(), value()) {}
120 
121   enum Mode {
122     STORE_BUFFER_ONLY,
123     INCREMENTAL,
124     INCREMENTAL_COMPACTION
125   };
126 
SometimesSetsUpAFrame()127   bool SometimesSetsUpAFrame() override { return false; }
128 
129   static const byte kTwoByteNopInstruction = 0x3c;  // Cmpb al, #imm8.
130   static const byte kTwoByteJumpInstruction = 0xeb;  // Jmp #imm8.
131 
132   static const byte kFiveByteNopInstruction = 0x3d;  // Cmpl eax, #imm32.
133   static const byte kFiveByteJumpInstruction = 0xe9;  // Jmp #imm32.
134 
GetMode(Code * stub)135   static Mode GetMode(Code* stub) {
136     byte first_instruction = stub->instruction_start()[0];
137     byte second_instruction = stub->instruction_start()[2];
138 
139     if (first_instruction == kTwoByteJumpInstruction) {
140       return INCREMENTAL;
141     }
142 
143     DCHECK(first_instruction == kTwoByteNopInstruction);
144 
145     if (second_instruction == kFiveByteJumpInstruction) {
146       return INCREMENTAL_COMPACTION;
147     }
148 
149     DCHECK(second_instruction == kFiveByteNopInstruction);
150 
151     return STORE_BUFFER_ONLY;
152   }
153 
Patch(Code * stub,Mode mode)154   static void Patch(Code* stub, Mode mode) {
155     switch (mode) {
156       case STORE_BUFFER_ONLY:
157         DCHECK(GetMode(stub) == INCREMENTAL ||
158                GetMode(stub) == INCREMENTAL_COMPACTION);
159         stub->instruction_start()[0] = kTwoByteNopInstruction;
160         stub->instruction_start()[2] = kFiveByteNopInstruction;
161         break;
162       case INCREMENTAL:
163         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
164         stub->instruction_start()[0] = kTwoByteJumpInstruction;
165         break;
166       case INCREMENTAL_COMPACTION:
167         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
168         stub->instruction_start()[0] = kTwoByteNopInstruction;
169         stub->instruction_start()[2] = kFiveByteJumpInstruction;
170         break;
171     }
172     DCHECK(GetMode(stub) == mode);
173     Assembler::FlushICache(stub->GetIsolate(), stub->instruction_start(), 7);
174   }
175 
176   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
177 
178  private:
179   // This is a helper class for freeing up 3 scratch registers, where the third
180   // is always ecx (needed for shift operations).  The input is two registers
181   // that must be preserved and one scratch register provided by the caller.
182   class RegisterAllocation {
183    public:
RegisterAllocation(Register object,Register address,Register scratch0)184     RegisterAllocation(Register object,
185                        Register address,
186                        Register scratch0)
187         : object_orig_(object),
188           address_orig_(address),
189           scratch0_orig_(scratch0),
190           object_(object),
191           address_(address),
192           scratch0_(scratch0) {
193       DCHECK(!AreAliased(scratch0, object, address, no_reg));
194       scratch1_ = GetRegThatIsNotEcxOr(object_, address_, scratch0_);
195       if (scratch0.is(ecx)) {
196         scratch0_ = GetRegThatIsNotEcxOr(object_, address_, scratch1_);
197       }
198       if (object.is(ecx)) {
199         object_ = GetRegThatIsNotEcxOr(address_, scratch0_, scratch1_);
200       }
201       if (address.is(ecx)) {
202         address_ = GetRegThatIsNotEcxOr(object_, scratch0_, scratch1_);
203       }
204       DCHECK(!AreAliased(scratch0_, object_, address_, ecx));
205     }
206 
Save(MacroAssembler * masm)207     void Save(MacroAssembler* masm) {
208       DCHECK(!address_orig_.is(object_));
209       DCHECK(object_.is(object_orig_) || address_.is(address_orig_));
210       DCHECK(!AreAliased(object_, address_, scratch1_, scratch0_));
211       DCHECK(!AreAliased(object_orig_, address_, scratch1_, scratch0_));
212       DCHECK(!AreAliased(object_, address_orig_, scratch1_, scratch0_));
213       // We don't have to save scratch0_orig_ because it was given to us as
214       // a scratch register.  But if we had to switch to a different reg then
215       // we should save the new scratch0_.
216       if (!scratch0_.is(scratch0_orig_)) masm->push(scratch0_);
217       if (!ecx.is(scratch0_orig_) &&
218           !ecx.is(object_orig_) &&
219           !ecx.is(address_orig_)) {
220         masm->push(ecx);
221       }
222       masm->push(scratch1_);
223       if (!address_.is(address_orig_)) {
224         masm->push(address_);
225         masm->mov(address_, address_orig_);
226       }
227       if (!object_.is(object_orig_)) {
228         masm->push(object_);
229         masm->mov(object_, object_orig_);
230       }
231     }
232 
Restore(MacroAssembler * masm)233     void Restore(MacroAssembler* masm) {
234       // These will have been preserved the entire time, so we just need to move
235       // them back.  Only in one case is the orig_ reg different from the plain
236       // one, since only one of them can alias with ecx.
237       if (!object_.is(object_orig_)) {
238         masm->mov(object_orig_, object_);
239         masm->pop(object_);
240       }
241       if (!address_.is(address_orig_)) {
242         masm->mov(address_orig_, address_);
243         masm->pop(address_);
244       }
245       masm->pop(scratch1_);
246       if (!ecx.is(scratch0_orig_) &&
247           !ecx.is(object_orig_) &&
248           !ecx.is(address_orig_)) {
249         masm->pop(ecx);
250       }
251       if (!scratch0_.is(scratch0_orig_)) masm->pop(scratch0_);
252     }
253 
254     // If we have to call into C then we need to save and restore all caller-
255     // saved registers that were not already preserved.  The caller saved
256     // registers are eax, ecx and edx.  The three scratch registers (incl. ecx)
257     // will be restored by other means so we don't bother pushing them here.
SaveCallerSaveRegisters(MacroAssembler * masm,SaveFPRegsMode mode)258     void SaveCallerSaveRegisters(MacroAssembler* masm, SaveFPRegsMode mode) {
259       masm->PushCallerSaved(mode, ecx, scratch0_, scratch1_);
260     }
261 
RestoreCallerSaveRegisters(MacroAssembler * masm,SaveFPRegsMode mode)262     inline void RestoreCallerSaveRegisters(MacroAssembler* masm,
263                                            SaveFPRegsMode mode) {
264       masm->PopCallerSaved(mode, ecx, scratch0_, scratch1_);
265     }
266 
object()267     inline Register object() { return object_; }
address()268     inline Register address() { return address_; }
scratch0()269     inline Register scratch0() { return scratch0_; }
scratch1()270     inline Register scratch1() { return scratch1_; }
271 
272    private:
273     Register object_orig_;
274     Register address_orig_;
275     Register scratch0_orig_;
276     Register object_;
277     Register address_;
278     Register scratch0_;
279     Register scratch1_;
280     // Third scratch register is always ecx.
281 
GetRegThatIsNotEcxOr(Register r1,Register r2,Register r3)282     Register GetRegThatIsNotEcxOr(Register r1,
283                                   Register r2,
284                                   Register r3) {
285       for (int i = 0; i < Register::kNumRegisters; i++) {
286         if (RegisterConfiguration::Crankshaft()->IsAllocatableGeneralCode(i)) {
287           Register candidate = Register::from_code(i);
288           if (candidate.is(ecx)) continue;
289           if (candidate.is(r1)) continue;
290           if (candidate.is(r2)) continue;
291           if (candidate.is(r3)) continue;
292           return candidate;
293         }
294       }
295       UNREACHABLE();
296       return no_reg;
297     }
298     friend class RecordWriteStub;
299   };
300 
301   enum OnNoNeedToInformIncrementalMarker {
302     kReturnOnNoNeedToInformIncrementalMarker,
303     kUpdateRememberedSetOnNoNeedToInformIncrementalMarker
304   };
305 
MajorKey()306   inline Major MajorKey() const final { return RecordWrite; }
307 
308   void Generate(MacroAssembler* masm) override;
309   void GenerateIncremental(MacroAssembler* masm, Mode mode);
310   void CheckNeedsToInformIncrementalMarker(
311       MacroAssembler* masm,
312       OnNoNeedToInformIncrementalMarker on_no_need,
313       Mode mode);
314   void InformIncrementalMarker(MacroAssembler* masm);
315 
Activate(Code * code)316   void Activate(Code* code) override {
317     code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
318   }
319 
object()320   Register object() const {
321     return Register::from_code(ObjectBits::decode(minor_key_));
322   }
323 
value()324   Register value() const {
325     return Register::from_code(ValueBits::decode(minor_key_));
326   }
327 
address()328   Register address() const {
329     return Register::from_code(AddressBits::decode(minor_key_));
330   }
331 
remembered_set_action()332   RememberedSetAction remembered_set_action() const {
333     return RememberedSetActionBits::decode(minor_key_);
334   }
335 
save_fp_regs_mode()336   SaveFPRegsMode save_fp_regs_mode() const {
337     return SaveFPRegsModeBits::decode(minor_key_);
338   }
339 
340   class ObjectBits: public BitField<int, 0, 3> {};
341   class ValueBits: public BitField<int, 3, 3> {};
342   class AddressBits: public BitField<int, 6, 3> {};
343   class RememberedSetActionBits: public BitField<RememberedSetAction, 9, 1> {};
344   class SaveFPRegsModeBits: public BitField<SaveFPRegsMode, 10, 1> {};
345 
346   RegisterAllocation regs_;
347 
348   DISALLOW_COPY_AND_ASSIGN(RecordWriteStub);
349 };
350 
351 
352 }  // namespace internal
353 }  // namespace v8
354 
355 #endif  // V8_IA32_CODE_STUBS_IA32_H_
356