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   // 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   virtual bool SometimesSetsUpAFrame() { 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,
120                   Register object,
121                   Register value,
122                   Register address,
123                   RememberedSetAction remembered_set_action,
124                   SaveFPRegsMode fp_mode)
125       : PlatformCodeStub(isolate),
126         regs_(object,   // An input reg.
127               address,  // An input reg.
128               value) {  // One scratch reg.
129     minor_key_ = ObjectBits::encode(object.code()) |
130                  ValueBits::encode(value.code()) |
131                  AddressBits::encode(address.code()) |
132                  RememberedSetActionBits::encode(remembered_set_action) |
133                  SaveFPRegsModeBits::encode(fp_mode);
134   }
135 
RecordWriteStub(uint32_t key,Isolate * isolate)136   RecordWriteStub(uint32_t key, Isolate* isolate)
137       : PlatformCodeStub(key, isolate), regs_(object(), address(), value()) {}
138 
139   enum Mode {
140     STORE_BUFFER_ONLY,
141     INCREMENTAL,
142     INCREMENTAL_COMPACTION
143   };
144 
SometimesSetsUpAFrame()145   virtual bool SometimesSetsUpAFrame() { return false; }
146 
147   static const byte kTwoByteNopInstruction = 0x3c;  // Cmpb al, #imm8.
148   static const byte kTwoByteJumpInstruction = 0xeb;  // Jmp #imm8.
149 
150   static const byte kFiveByteNopInstruction = 0x3d;  // Cmpl eax, #imm32.
151   static const byte kFiveByteJumpInstruction = 0xe9;  // Jmp #imm32.
152 
GetMode(Code * stub)153   static Mode GetMode(Code* stub) {
154     byte first_instruction = stub->instruction_start()[0];
155     byte second_instruction = stub->instruction_start()[2];
156 
157     if (first_instruction == kTwoByteJumpInstruction) {
158       return INCREMENTAL;
159     }
160 
161     DCHECK(first_instruction == kTwoByteNopInstruction);
162 
163     if (second_instruction == kFiveByteJumpInstruction) {
164       return INCREMENTAL_COMPACTION;
165     }
166 
167     DCHECK(second_instruction == kFiveByteNopInstruction);
168 
169     return STORE_BUFFER_ONLY;
170   }
171 
Patch(Code * stub,Mode mode)172   static void Patch(Code* stub, Mode mode) {
173     switch (mode) {
174       case STORE_BUFFER_ONLY:
175         DCHECK(GetMode(stub) == INCREMENTAL ||
176                GetMode(stub) == INCREMENTAL_COMPACTION);
177         stub->instruction_start()[0] = kTwoByteNopInstruction;
178         stub->instruction_start()[2] = kFiveByteNopInstruction;
179         break;
180       case INCREMENTAL:
181         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
182         stub->instruction_start()[0] = kTwoByteJumpInstruction;
183         break;
184       case INCREMENTAL_COMPACTION:
185         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
186         stub->instruction_start()[0] = kTwoByteNopInstruction;
187         stub->instruction_start()[2] = kFiveByteJumpInstruction;
188         break;
189     }
190     DCHECK(GetMode(stub) == mode);
191     CpuFeatures::FlushICache(stub->instruction_start(), 7);
192   }
193 
194   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
195 
196  private:
197   // This is a helper class for freeing up 3 scratch registers, where the third
198   // is always ecx (needed for shift operations).  The input is two registers
199   // that must be preserved and one scratch register provided by the caller.
200   class RegisterAllocation {
201    public:
RegisterAllocation(Register object,Register address,Register scratch0)202     RegisterAllocation(Register object,
203                        Register address,
204                        Register scratch0)
205         : object_orig_(object),
206           address_orig_(address),
207           scratch0_orig_(scratch0),
208           object_(object),
209           address_(address),
210           scratch0_(scratch0) {
211       DCHECK(!AreAliased(scratch0, object, address, no_reg));
212       scratch1_ = GetRegThatIsNotEcxOr(object_, address_, scratch0_);
213       if (scratch0.is(ecx)) {
214         scratch0_ = GetRegThatIsNotEcxOr(object_, address_, scratch1_);
215       }
216       if (object.is(ecx)) {
217         object_ = GetRegThatIsNotEcxOr(address_, scratch0_, scratch1_);
218       }
219       if (address.is(ecx)) {
220         address_ = GetRegThatIsNotEcxOr(object_, scratch0_, scratch1_);
221       }
222       DCHECK(!AreAliased(scratch0_, object_, address_, ecx));
223     }
224 
Save(MacroAssembler * masm)225     void Save(MacroAssembler* masm) {
226       DCHECK(!address_orig_.is(object_));
227       DCHECK(object_.is(object_orig_) || address_.is(address_orig_));
228       DCHECK(!AreAliased(object_, address_, scratch1_, scratch0_));
229       DCHECK(!AreAliased(object_orig_, address_, scratch1_, scratch0_));
230       DCHECK(!AreAliased(object_, address_orig_, scratch1_, scratch0_));
231       // We don't have to save scratch0_orig_ because it was given to us as
232       // a scratch register.  But if we had to switch to a different reg then
233       // we should save the new scratch0_.
234       if (!scratch0_.is(scratch0_orig_)) masm->push(scratch0_);
235       if (!ecx.is(scratch0_orig_) &&
236           !ecx.is(object_orig_) &&
237           !ecx.is(address_orig_)) {
238         masm->push(ecx);
239       }
240       masm->push(scratch1_);
241       if (!address_.is(address_orig_)) {
242         masm->push(address_);
243         masm->mov(address_, address_orig_);
244       }
245       if (!object_.is(object_orig_)) {
246         masm->push(object_);
247         masm->mov(object_, object_orig_);
248       }
249     }
250 
Restore(MacroAssembler * masm)251     void Restore(MacroAssembler* masm) {
252       // These will have been preserved the entire time, so we just need to move
253       // them back.  Only in one case is the orig_ reg different from the plain
254       // one, since only one of them can alias with ecx.
255       if (!object_.is(object_orig_)) {
256         masm->mov(object_orig_, object_);
257         masm->pop(object_);
258       }
259       if (!address_.is(address_orig_)) {
260         masm->mov(address_orig_, address_);
261         masm->pop(address_);
262       }
263       masm->pop(scratch1_);
264       if (!ecx.is(scratch0_orig_) &&
265           !ecx.is(object_orig_) &&
266           !ecx.is(address_orig_)) {
267         masm->pop(ecx);
268       }
269       if (!scratch0_.is(scratch0_orig_)) masm->pop(scratch0_);
270     }
271 
272     // If we have to call into C then we need to save and restore all caller-
273     // saved registers that were not already preserved.  The caller saved
274     // registers are eax, ecx and edx.  The three scratch registers (incl. ecx)
275     // will be restored by other means so we don't bother pushing them here.
SaveCallerSaveRegisters(MacroAssembler * masm,SaveFPRegsMode mode)276     void SaveCallerSaveRegisters(MacroAssembler* masm, SaveFPRegsMode mode) {
277       if (!scratch0_.is(eax) && !scratch1_.is(eax)) masm->push(eax);
278       if (!scratch0_.is(edx) && !scratch1_.is(edx)) masm->push(edx);
279       if (mode == kSaveFPRegs) {
280         masm->sub(esp,
281                   Immediate(kDoubleSize * (XMMRegister::kMaxNumRegisters - 1)));
282         // Save all XMM registers except XMM0.
283         for (int i = XMMRegister::kMaxNumRegisters - 1; i > 0; i--) {
284           XMMRegister reg = XMMRegister::from_code(i);
285           masm->movsd(Operand(esp, (i - 1) * kDoubleSize), reg);
286         }
287       }
288     }
289 
RestoreCallerSaveRegisters(MacroAssembler * masm,SaveFPRegsMode mode)290     inline void RestoreCallerSaveRegisters(MacroAssembler*masm,
291                                            SaveFPRegsMode mode) {
292       if (mode == kSaveFPRegs) {
293         // Restore all XMM registers except XMM0.
294         for (int i = XMMRegister::kMaxNumRegisters - 1; i > 0; i--) {
295           XMMRegister reg = XMMRegister::from_code(i);
296           masm->movsd(reg, Operand(esp, (i - 1) * kDoubleSize));
297         }
298         masm->add(esp,
299                   Immediate(kDoubleSize * (XMMRegister::kMaxNumRegisters - 1)));
300       }
301       if (!scratch0_.is(edx) && !scratch1_.is(edx)) masm->pop(edx);
302       if (!scratch0_.is(eax) && !scratch1_.is(eax)) masm->pop(eax);
303     }
304 
object()305     inline Register object() { return object_; }
address()306     inline Register address() { return address_; }
scratch0()307     inline Register scratch0() { return scratch0_; }
scratch1()308     inline Register scratch1() { return scratch1_; }
309 
310    private:
311     Register object_orig_;
312     Register address_orig_;
313     Register scratch0_orig_;
314     Register object_;
315     Register address_;
316     Register scratch0_;
317     Register scratch1_;
318     // Third scratch register is always ecx.
319 
GetRegThatIsNotEcxOr(Register r1,Register r2,Register r3)320     Register GetRegThatIsNotEcxOr(Register r1,
321                                   Register r2,
322                                   Register r3) {
323       for (int i = 0; i < Register::NumAllocatableRegisters(); i++) {
324         Register candidate = Register::FromAllocationIndex(i);
325         if (candidate.is(ecx)) continue;
326         if (candidate.is(r1)) continue;
327         if (candidate.is(r2)) continue;
328         if (candidate.is(r3)) continue;
329         return candidate;
330       }
331       UNREACHABLE();
332       return no_reg;
333     }
334     friend class RecordWriteStub;
335   };
336 
337   enum OnNoNeedToInformIncrementalMarker {
338     kReturnOnNoNeedToInformIncrementalMarker,
339     kUpdateRememberedSetOnNoNeedToInformIncrementalMarker
340   };
341 
MajorKey()342   virtual inline Major MajorKey() const FINAL OVERRIDE { return RecordWrite; }
343 
344   virtual void Generate(MacroAssembler* masm) OVERRIDE;
345   void GenerateIncremental(MacroAssembler* masm, Mode mode);
346   void CheckNeedsToInformIncrementalMarker(
347       MacroAssembler* masm,
348       OnNoNeedToInformIncrementalMarker on_no_need,
349       Mode mode);
350   void InformIncrementalMarker(MacroAssembler* masm);
351 
Activate(Code * code)352   void Activate(Code* code) {
353     code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
354   }
355 
object()356   Register object() const {
357     return Register::from_code(ObjectBits::decode(minor_key_));
358   }
359 
value()360   Register value() const {
361     return Register::from_code(ValueBits::decode(minor_key_));
362   }
363 
address()364   Register address() const {
365     return Register::from_code(AddressBits::decode(minor_key_));
366   }
367 
remembered_set_action()368   RememberedSetAction remembered_set_action() const {
369     return RememberedSetActionBits::decode(minor_key_);
370   }
371 
save_fp_regs_mode()372   SaveFPRegsMode save_fp_regs_mode() const {
373     return SaveFPRegsModeBits::decode(minor_key_);
374   }
375 
376   class ObjectBits: public BitField<int, 0, 3> {};
377   class ValueBits: public BitField<int, 3, 3> {};
378   class AddressBits: public BitField<int, 6, 3> {};
379   class RememberedSetActionBits: public BitField<RememberedSetAction, 9, 1> {};
380   class SaveFPRegsModeBits: public BitField<SaveFPRegsMode, 10, 1> {};
381 
382   RegisterAllocation regs_;
383 
384   DISALLOW_COPY_AND_ASSIGN(RecordWriteStub);
385 };
386 
387 
388 } }  // namespace v8::internal
389 
390 #endif  // V8_IA32_CODE_STUBS_IA32_H_
391