src/x64/code-stubs-x64.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_X64_CODE_STUBS_X64_H_
   6 #define V8_X64_CODE_STUBS_X64_H_
   7
   8 namespace v8 {
   9 namespace internal {
  10
  11
  12 void ArrayNativeCode(MacroAssembler* masm, Label* call_generic_code);
  13
  14
  15 class StringHelper : public AllStatic {
  16  public:
  17   // Generate code for copying characters using the rep movs instruction.
  18   // Copies rcx characters from rsi to rdi. Copying of overlapping regions is
  19   // not supported.
  20   static void GenerateCopyCharacters(MacroAssembler* masm,
  21                                      Register dest,
  22                                      Register src,
  23                                      Register count,
  24                                      String::Encoding encoding);
  25
  26   // Compares two flat one-byte strings and returns result in rax.
  27   static void GenerateCompareFlatOneByteStrings(
  28       MacroAssembler* masm, Register left, Register right, Register scratch1,
  29       Register scratch2, Register scratch3, Register scratch4);
  30
  31   // Compares two flat one-byte strings for equality and returns result in rax.
  32   static void GenerateFlatOneByteStringEquals(MacroAssembler* masm,
  33                                               Register left, Register right,
  34                                               Register scratch1,
  35                                               Register scratch2);
  36
  37  private:
  38   static void GenerateOneByteCharsCompareLoop(
  39       MacroAssembler* masm, Register left, Register right, Register length,
  40       Register scratch, Label* chars_not_equal,
  41       Label::Distance near_jump = Label::kFar);
  42
  43   DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
  44 };
  45
  46
  47 class NameDictionaryLookupStub: public PlatformCodeStub {
  48  public:
  49   enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };
  50
  51   NameDictionaryLookupStub(Isolate* isolate, Register dictionary,
  52                            Register result, Register index, LookupMode mode)
  53       : PlatformCodeStub(isolate) {
  54     minor_key_ = DictionaryBits::encode(dictionary.code()) |
  55                  ResultBits::encode(result.code()) |
  56                  IndexBits::encode(index.code()) | LookupModeBits::encode(mode);
  57   }
  58
  59   static void GenerateNegativeLookup(MacroAssembler* masm,
  60                                      Label* miss,
  61                                      Label* done,
  62                                      Register properties,
  63                                      Handle<Name> name,
  64                                      Register r0);
  65
  66   static void GeneratePositiveLookup(MacroAssembler* masm,
  67                                      Label* miss,
  68                                      Label* done,
  69                                      Register elements,
  70                                      Register name,
  71                                      Register r0,
  72                                      Register r1);
  73
  74   bool SometimesSetsUpAFrame() override { return false; }
  75
  76  private:
  77   static const int kInlinedProbes = 4;
  78   static const int kTotalProbes = 20;
  79
  80   static const int kCapacityOffset =
  81       NameDictionary::kHeaderSize +
  82       NameDictionary::kCapacityIndex * kPointerSize;
  83
  84   static const int kElementsStartOffset =
  85       NameDictionary::kHeaderSize +
  86       NameDictionary::kElementsStartIndex * kPointerSize;
  87
  88   Register dictionary() const {
  89     return Register::from_code(DictionaryBits::decode(minor_key_));
  90   }
  91
  92   Register result() const {
  93     return Register::from_code(ResultBits::decode(minor_key_));
  94   }
  95
  96   Register index() const {
  97     return Register::from_code(IndexBits::decode(minor_key_));
  98   }
  99
 100   LookupMode mode() const { return LookupModeBits::decode(minor_key_); }
 101
 102   class DictionaryBits: public BitField<int, 0, 4> {};
 103   class ResultBits: public BitField<int, 4, 4> {};
 104   class IndexBits: public BitField<int, 8, 4> {};
 105   class LookupModeBits: public BitField<LookupMode, 12, 1> {};
 106
 107   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
 108   DEFINE_PLATFORM_CODE_STUB(NameDictionaryLookup, PlatformCodeStub);
 109 };
 110
 111
 112 class RecordWriteStub: public PlatformCodeStub {
 113  public:
 114   RecordWriteStub(Isolate* isolate, Register object, Register value,
 115                   Register address, RememberedSetAction remembered_set_action,
 116                   SaveFPRegsMode fp_mode)
 117       : PlatformCodeStub(isolate),
 118         regs_(object,   // An input reg.
 119               address,  // An input reg.
 120               value) {  // One scratch reg.
 121     minor_key_ = ObjectBits::encode(object.code()) |
 122                  ValueBits::encode(value.code()) |
 123                  AddressBits::encode(address.code()) |
 124                  RememberedSetActionBits::encode(remembered_set_action) |
 125                  SaveFPRegsModeBits::encode(fp_mode);
 126   }
 127
 128   RecordWriteStub(uint32_t key, Isolate* isolate)
 129       : PlatformCodeStub(key, isolate), regs_(object(), address(), value()) {}
 130
 131   enum Mode {
 132     STORE_BUFFER_ONLY,
 133     INCREMENTAL,
 134     INCREMENTAL_COMPACTION
 135   };
 136
 137   bool SometimesSetsUpAFrame() override { return false; }
 138
 139   static const byte kTwoByteNopInstruction = 0x3c;  // Cmpb al, #imm8.
 140   static const byte kTwoByteJumpInstruction = 0xeb;  // Jmp #imm8.
 141
 142   static const byte kFiveByteNopInstruction = 0x3d;  // Cmpl eax, #imm32.
 143   static const byte kFiveByteJumpInstruction = 0xe9;  // Jmp #imm32.
 144
 145   static Mode GetMode(Code* stub) {
 146     byte first_instruction = stub->instruction_start()[0];
 147     byte second_instruction = stub->instruction_start()[2];
 148
 149     if (first_instruction == kTwoByteJumpInstruction) {
 150       return INCREMENTAL;
 151     }
 152
 153     DCHECK(first_instruction == kTwoByteNopInstruction);
 154
 155     if (second_instruction == kFiveByteJumpInstruction) {
 156       return INCREMENTAL_COMPACTION;
 157     }
 158
 159     DCHECK(second_instruction == kFiveByteNopInstruction);
 160
 161     return STORE_BUFFER_ONLY;
 162   }
 163
 164   static void Patch(Code* stub, Mode mode) {
 165     switch (mode) {
 166       case STORE_BUFFER_ONLY:
 167         DCHECK(GetMode(stub) == INCREMENTAL ||
 168                GetMode(stub) == INCREMENTAL_COMPACTION);
 169         stub->instruction_start()[0] = kTwoByteNopInstruction;
 170         stub->instruction_start()[2] = kFiveByteNopInstruction;
 171         break;
 172       case INCREMENTAL:
 173         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
 174         stub->instruction_start()[0] = kTwoByteJumpInstruction;
 175         break;
 176       case INCREMENTAL_COMPACTION:
 177         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
 178         stub->instruction_start()[0] = kTwoByteNopInstruction;
 179         stub->instruction_start()[2] = kFiveByteJumpInstruction;
 180         break;
 181     }
 182     DCHECK(GetMode(stub) == mode);
 183     Assembler::FlushICache(stub->GetIsolate(), stub->instruction_start(), 7);
 184   }
 185
 186   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
 187
 188  private:
 189   // This is a helper class for freeing up 3 scratch registers, where the third
 190   // is always rcx (needed for shift operations).  The input is two registers
 191   // that must be preserved and one scratch register provided by the caller.
 192   class RegisterAllocation {
 193    public:
 194     RegisterAllocation(Register object,
 195                        Register address,
 196                        Register scratch0)
 197         : object_orig_(object),
 198           address_orig_(address),
 199           scratch0_orig_(scratch0),
 200           object_(object),
 201           address_(address),
 202           scratch0_(scratch0) {
 203       DCHECK(!AreAliased(scratch0, object, address, no_reg));
 204       scratch1_ = GetRegThatIsNotRcxOr(object_, address_, scratch0_);
 205       if (scratch0.is(rcx)) {
 206         scratch0_ = GetRegThatIsNotRcxOr(object_, address_, scratch1_);
 207       }
 208       if (object.is(rcx)) {
 209         object_ = GetRegThatIsNotRcxOr(address_, scratch0_, scratch1_);
 210       }
 211       if (address.is(rcx)) {
 212         address_ = GetRegThatIsNotRcxOr(object_, scratch0_, scratch1_);
 213       }
 214       DCHECK(!AreAliased(scratch0_, object_, address_, rcx));
 215     }
 216
 217     void Save(MacroAssembler* masm) {
 218       DCHECK(!address_orig_.is(object_));
 219       DCHECK(object_.is(object_orig_) || address_.is(address_orig_));
 220       DCHECK(!AreAliased(object_, address_, scratch1_, scratch0_));
 221       DCHECK(!AreAliased(object_orig_, address_, scratch1_, scratch0_));
 222       DCHECK(!AreAliased(object_, address_orig_, scratch1_, scratch0_));
 223       // We don't have to save scratch0_orig_ because it was given to us as
 224       // a scratch register.  But if we had to switch to a different reg then
 225       // we should save the new scratch0_.
 226       if (!scratch0_.is(scratch0_orig_)) masm->Push(scratch0_);
 227       if (!rcx.is(scratch0_orig_) &&
 228           !rcx.is(object_orig_) &&
 229           !rcx.is(address_orig_)) {
 230         masm->Push(rcx);
 231       }
 232       masm->Push(scratch1_);
 233       if (!address_.is(address_orig_)) {
 234         masm->Push(address_);
 235         masm->movp(address_, address_orig_);
 236       }
 237       if (!object_.is(object_orig_)) {
 238         masm->Push(object_);
 239         masm->movp(object_, object_orig_);
 240       }
 241     }
 242
 243     void Restore(MacroAssembler* masm) {
 244       // These will have been preserved the entire time, so we just need to move
 245       // them back.  Only in one case is the orig_ reg different from the plain
 246       // one, since only one of them can alias with rcx.
 247       if (!object_.is(object_orig_)) {
 248         masm->movp(object_orig_, object_);
 249         masm->Pop(object_);
 250       }
 251       if (!address_.is(address_orig_)) {
 252         masm->movp(address_orig_, address_);
 253         masm->Pop(address_);
 254       }
 255       masm->Pop(scratch1_);
 256       if (!rcx.is(scratch0_orig_) &&
 257           !rcx.is(object_orig_) &&
 258           !rcx.is(address_orig_)) {
 259         masm->Pop(rcx);
 260       }
 261       if (!scratch0_.is(scratch0_orig_)) masm->Pop(scratch0_);
 262     }
 263
 264     // If we have to call into C then we need to save and restore all caller-
 265     // saved registers that were not already preserved.
 266
 267     // The three scratch registers (incl. rcx) will be restored by other means
 268     // so we don't bother pushing them here.  Rbx, rbp and r12-15 are callee
 269     // save and don't need to be preserved.
 270     void SaveCallerSaveRegisters(MacroAssembler* masm, SaveFPRegsMode mode) {
 271       masm->PushCallerSaved(mode, scratch0_, scratch1_, rcx);
 272     }
 273
 274     inline void RestoreCallerSaveRegisters(MacroAssembler*masm,
 275                                            SaveFPRegsMode mode) {
 276       masm->PopCallerSaved(mode, scratch0_, scratch1_, rcx);
 277     }
 278
 279     inline Register object() { return object_; }
 280     inline Register address() { return address_; }
 281     inline Register scratch0() { return scratch0_; }
 282     inline Register scratch1() { return scratch1_; }
 283
 284    private:
 285     Register object_orig_;
 286     Register address_orig_;
 287     Register scratch0_orig_;
 288     Register object_;
 289     Register address_;
 290     Register scratch0_;
 291     Register scratch1_;
 292     // Third scratch register is always rcx.
 293
 294     Register GetRegThatIsNotRcxOr(Register r1,
 295                                   Register r2,
 296                                   Register r3) {
 297       for (int i = 0; i < Register::NumAllocatableRegisters(); i++) {
 298         Register candidate = Register::FromAllocationIndex(i);
 299         if (candidate.is(rcx)) continue;
 300         if (candidate.is(r1)) continue;
 301         if (candidate.is(r2)) continue;
 302         if (candidate.is(r3)) continue;
 303         return candidate;
 304       }
 305       UNREACHABLE();
 306       return no_reg;
 307     }
 308     friend class RecordWriteStub;
 309   };
 310
 311   enum OnNoNeedToInformIncrementalMarker {
 312     kReturnOnNoNeedToInformIncrementalMarker,
 313     kUpdateRememberedSetOnNoNeedToInformIncrementalMarker
 314   };
 315
 316   Major MajorKey() const final { return RecordWrite; }
 317
 318   void Generate(MacroAssembler* masm) override;
 319   void GenerateIncremental(MacroAssembler* masm, Mode mode);
 320   void CheckNeedsToInformIncrementalMarker(
 321       MacroAssembler* masm,
 322       OnNoNeedToInformIncrementalMarker on_no_need,
 323       Mode mode);
 324   void InformIncrementalMarker(MacroAssembler* masm);
 325
 326   void Activate(Code* code) override {
 327     code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
 328   }
 329
 330   Register object() const {
 331     return Register::from_code(ObjectBits::decode(minor_key_));
 332   }
 333
 334   Register value() const {
 335     return Register::from_code(ValueBits::decode(minor_key_));
 336   }
 337
 338   Register address() const {
 339     return Register::from_code(AddressBits::decode(minor_key_));
 340   }
 341
 342   RememberedSetAction remembered_set_action() const {
 343     return RememberedSetActionBits::decode(minor_key_);
 344   }
 345
 346   SaveFPRegsMode save_fp_regs_mode() const {
 347     return SaveFPRegsModeBits::decode(minor_key_);
 348   }
 349
 350   class ObjectBits: public BitField<int, 0, 4> {};
 351   class ValueBits: public BitField<int, 4, 4> {};
 352   class AddressBits: public BitField<int, 8, 4> {};
 353   class RememberedSetActionBits: public BitField<RememberedSetAction, 12, 1> {};
 354   class SaveFPRegsModeBits: public BitField<SaveFPRegsMode, 13, 1> {};
 355
 356   Label slow_;
 357   RegisterAllocation regs_;
 358
 359   DISALLOW_COPY_AND_ASSIGN(RecordWriteStub);
 360 };
 361
 362
 363 }  // namespace internal
 364 }  // namespace v8
 365
 366 #endif  // V8_X64_CODE_STUBS_X64_H_