src/v8/src/ia32/code-stubs-ia32.h

   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
  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
  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
  93   Register dictionary() const {
  94     return Register::from_code(DictionaryBits::decode(minor_key_));
  95   }
  96
  97   Register result() const {
  98     return Register::from_code(ResultBits::decode(minor_key_));
  99   }
 100
 101   Register index() const {
 102     return Register::from_code(IndexBits::decode(minor_key_));
 103   }
 104
 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:
 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
 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
 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
 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
 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:
 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
 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
 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.
 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
 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
 305     inline Register object() { return object_; }
 306     inline Register address() { return address_; }
 307     inline Register scratch0() { return scratch0_; }
 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
 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
 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
 352   void Activate(Code* code) {
 353     code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
 354   }
 355
 356   Register object() const {
 357     return Register::from_code(ObjectBits::decode(minor_key_));
 358   }
 359
 360   Register value() const {
 361     return Register::from_code(ValueBits::decode(minor_key_));
 362   }
 363
 364   Register address() const {
 365     return Register::from_code(AddressBits::decode(minor_key_));
 366   }
 367
 368   RememberedSetAction remembered_set_action() const {
 369     return RememberedSetActionBits::decode(minor_key_);
 370   }
 371
 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_