CSE2410 Fall 2014 Bounce

// Copyright 2011 the V8 project authors. All rights reserved.

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

//     * Redistributions of source code must retain the above copyright

//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above

//       copyright notice, this list of conditions and the following

//       disclaimer in the documentation and/or other materials provided

//       with the distribution.

//     * Neither the name of Google Inc. nor the names of its

//       contributors may be used to endorse or promote products derived

//       from this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef V8_X64_CODE_STUBS_X64_H_

#define V8_X64_CODE_STUBS_X64_H_

#include "ic-inl.h"

#include "type-info.h"

namespace v8 {

namespace internal {

void ArrayNativeCode(MacroAssembler* masm, Label* call_generic_code);

// Compute a transcendental math function natively, or call the

// TranscendentalCache runtime function.

class TranscendentalCacheStub: public PlatformCodeStub {

 public:

  enum ArgumentType {

    TAGGED = 0,

    UNTAGGED = 1 << TranscendentalCache::kTranscendentalTypeBits

  };

  explicit TranscendentalCacheStub(TranscendentalCache::Type type,

                                   ArgumentType argument_type)

      : type_(type), argument_type_(argument_type) {}

  void Generate(MacroAssembler* masm);

  static void GenerateOperation(MacroAssembler* masm,

                                TranscendentalCache::Type type);

 private:

  TranscendentalCache::Type type_;

  ArgumentType argument_type_;

  Major MajorKey() { return TranscendentalCache; }

  int MinorKey() { return type_ | argument_type_; }

  Runtime::FunctionId RuntimeFunction();

};

class StoreBufferOverflowStub: public PlatformCodeStub {

 public:

  explicit StoreBufferOverflowStub(SaveFPRegsMode save_fp)

      : save_doubles_(save_fp) { }

  void Generate(MacroAssembler* masm);

  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE { return true; }

  static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);

  virtual bool SometimesSetsUpAFrame() { return false; }

 private:

  SaveFPRegsMode save_doubles_;

  Major MajorKey() { return StoreBufferOverflow; }

  int MinorKey() { return (save_doubles_ == kSaveFPRegs) ? 1 : 0; }

};

class StringHelper : public AllStatic {

 public:

  // Generate code for copying characters using a simple loop. This should only

  // be used in places where the number of characters is small and the

  // additional setup and checking in GenerateCopyCharactersREP adds too much

  // overhead. Copying of overlapping regions is not supported.

  static void GenerateCopyCharacters(MacroAssembler* masm,

                                     Register dest,

                                     Register src,

                                     Register count,

                                     bool ascii);

  // Generate code for copying characters using the rep movs instruction.

  // Copies rcx characters from rsi to rdi. Copying of overlapping regions is

  // not supported.

  static void GenerateCopyCharactersREP(MacroAssembler* masm,

                                        Register dest,     // Must be rdi.

                                        Register src,      // Must be rsi.

                                        Register count,    // Must be rcx.

                                        bool ascii);

  // Probe the string table for a two character string. If the string is

  // not found by probing a jump to the label not_found is performed. This jump

  // does not guarantee that the string is not in the string table. If the

  // string is found the code falls through with the string in register rax.

  static void GenerateTwoCharacterStringTableProbe(MacroAssembler* masm,

                                                   Register c1,

                                                   Register c2,

                                                   Register scratch1,

                                                   Register scratch2,

                                                   Register scratch3,

                                                   Register scratch4,

                                                   Label* not_found);

  // Generate string hash.

  static void GenerateHashInit(MacroAssembler* masm,

                               Register hash,

                               Register character,

                               Register scratch);

  static void GenerateHashAddCharacter(MacroAssembler* masm,

                                       Register hash,

                                       Register character,

                                       Register scratch);

  static void GenerateHashGetHash(MacroAssembler* masm,

                                  Register hash,

                                  Register scratch);

 private:

  DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);

};

class StringAddStub: public PlatformCodeStub {

 public:

  explicit StringAddStub(StringAddFlags flags) : flags_(flags) {}

 private:

  Major MajorKey() { return StringAdd; }

  int MinorKey() { return flags_; }

  void Generate(MacroAssembler* masm);

  void GenerateConvertArgument(MacroAssembler* masm,

                               int stack_offset,

                               Register arg,

                               Register scratch1,

                               Register scratch2,

                               Register scratch3,

                               Label* slow);

  void GenerateRegisterArgsPush(MacroAssembler* masm);

  void GenerateRegisterArgsPop(MacroAssembler* masm, Register temp);

  const StringAddFlags flags_;

};

class SubStringStub: public PlatformCodeStub {

 public:

  SubStringStub() {}

 private:

  Major MajorKey() { return SubString; }

  int MinorKey() { return 0; }

  void Generate(MacroAssembler* masm);

};

class StringCompareStub: public PlatformCodeStub {

 public:

  StringCompareStub() {}

  // Compares two flat ASCII strings and returns result in rax.

  static void GenerateCompareFlatAsciiStrings(MacroAssembler* masm,

                                              Register left,

                                              Register right,

                                              Register scratch1,

                                              Register scratch2,

                                              Register scratch3,

                                              Register scratch4);

  // Compares two flat ASCII strings for equality and returns result

  // in rax.

  static void GenerateFlatAsciiStringEquals(MacroAssembler* masm,

                                            Register left,

                                            Register right,

                                            Register scratch1,

                                            Register scratch2);

 private:

  virtual Major MajorKey() { return StringCompare; }

  virtual int MinorKey() { return 0; }

  virtual void Generate(MacroAssembler* masm);

  static void GenerateAsciiCharsCompareLoop(

      MacroAssembler* masm,

      Register left,

      Register right,

      Register length,

      Register scratch,

      Label* chars_not_equal,

      Label::Distance near_jump = Label::kFar);

};

class NameDictionaryLookupStub: public PlatformCodeStub {

 public:

  enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };

  NameDictionaryLookupStub(Register dictionary,

                           Register result,

                           Register index,

                           LookupMode mode)

      : dictionary_(dictionary), result_(result), index_(index), mode_(mode) { }

  void Generate(MacroAssembler* masm);

  static void GenerateNegativeLookup(MacroAssembler* masm,

                                     Label* miss,

                                     Label* done,

                                     Register properties,

                                     Handle<Name> name,

                                     Register r0);

  static void GeneratePositiveLookup(MacroAssembler* masm,

                                     Label* miss,

                                     Label* done,

                                     Register elements,

                                     Register name,

                                     Register r0,

                                     Register r1);

  virtual bool SometimesSetsUpAFrame() { return false; }

 private:

  static const int kInlinedProbes = 4;

  static const int kTotalProbes = 20;

  static const int kCapacityOffset =

      NameDictionary::kHeaderSize +

      NameDictionary::kCapacityIndex * kPointerSize;

  static const int kElementsStartOffset =

      NameDictionary::kHeaderSize +

      NameDictionary::kElementsStartIndex * kPointerSize;

  Major MajorKey() { return NameDictionaryLookup; }

  int MinorKey() {

    return DictionaryBits::encode(dictionary_.code()) |

        ResultBits::encode(result_.code()) |

        IndexBits::encode(index_.code()) |

        LookupModeBits::encode(mode_);

  }

  class DictionaryBits: public BitField<int, 0, 4> {};

  class ResultBits: public BitField<int, 4, 4> {};

  class IndexBits: public BitField<int, 8, 4> {};

  class LookupModeBits: public BitField<LookupMode, 12, 1> {};

  Register dictionary_;

  Register result_;

  Register index_;

  LookupMode mode_;

};

class RecordWriteStub: public PlatformCodeStub {

 public:

  RecordWriteStub(Register object,

                  Register value,

                  Register address,

                  RememberedSetAction remembered_set_action,

                  SaveFPRegsMode fp_mode)

      : object_(object),

        value_(value),

        address_(address),

        remembered_set_action_(remembered_set_action),

        save_fp_regs_mode_(fp_mode),

        regs_(object,   // An input reg.

              address,  // An input reg.

              value) {  // One scratch reg.

  }

  enum Mode {

    STORE_BUFFER_ONLY,

    INCREMENTAL,

    INCREMENTAL_COMPACTION

  };

  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE;

  static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);

  virtual bool SometimesSetsUpAFrame() { return false; }

  static const byte kTwoByteNopInstruction = 0x3c;  // Cmpb al, #imm8.

  static const byte kTwoByteJumpInstruction = 0xeb;  // Jmp #imm8.

  static const byte kFiveByteNopInstruction = 0x3d;  // Cmpl eax, #imm32.

  static const byte kFiveByteJumpInstruction = 0xe9;  // Jmp #imm32.

  static Mode GetMode(Code* stub) {

    byte first_instruction = stub->instruction_start()[0];

    byte second_instruction = stub->instruction_start()[2];

    if (first_instruction == kTwoByteJumpInstruction) {

      return INCREMENTAL;

    }

    ASSERT(first_instruction == kTwoByteNopInstruction);

    if (second_instruction == kFiveByteJumpInstruction) {

      return INCREMENTAL_COMPACTION;

    }

    ASSERT(second_instruction == kFiveByteNopInstruction);

    return STORE_BUFFER_ONLY;

  }

  static void Patch(Code* stub, Mode mode) {

    switch (mode) {

      case STORE_BUFFER_ONLY:

        ASSERT(GetMode(stub) == INCREMENTAL ||

               GetMode(stub) == INCREMENTAL_COMPACTION);

        stub->instruction_start()[0] = kTwoByteNopInstruction;

        stub->instruction_start()[2] = kFiveByteNopInstruction;

        break;

      case INCREMENTAL:

        ASSERT(GetMode(stub) == STORE_BUFFER_ONLY);

        stub->instruction_start()[0] = kTwoByteJumpInstruction;

        break;

      case INCREMENTAL_COMPACTION:

        ASSERT(GetMode(stub) == STORE_BUFFER_ONLY);

        stub->instruction_start()[0] = kTwoByteNopInstruction;

        stub->instruction_start()[2] = kFiveByteJumpInstruction;

        break;

    }

    ASSERT(GetMode(stub) == mode);

    CPU::FlushICache(stub->instruction_start(), 7);

  }

 private:

  // This is a helper class for freeing up 3 scratch registers, where the third

  // is always rcx (needed for shift operations).  The input is two registers

  // that must be preserved and one scratch register provided by the caller.

  class RegisterAllocation {

   public:

    RegisterAllocation(Register object,

                       Register address,

                       Register scratch0)

        : object_orig_(object),

          address_orig_(address),

          scratch0_orig_(scratch0),

          object_(object),

          address_(address),

          scratch0_(scratch0) {

      ASSERT(!AreAliased(scratch0, object, address, no_reg));

      scratch1_ = GetRegThatIsNotRcxOr(object_, address_, scratch0_);

      if (scratch0.is(rcx)) {

        scratch0_ = GetRegThatIsNotRcxOr(object_, address_, scratch1_);

      }

      if (object.is(rcx)) {

        object_ = GetRegThatIsNotRcxOr(address_, scratch0_, scratch1_);

      }

      if (address.is(rcx)) {

        address_ = GetRegThatIsNotRcxOr(object_, scratch0_, scratch1_);

      }

      ASSERT(!AreAliased(scratch0_, object_, address_, rcx));

    }

    void Save(MacroAssembler* masm) {

      ASSERT(!address_orig_.is(object_));

      ASSERT(object_.is(object_orig_) || address_.is(address_orig_));

      ASSERT(!AreAliased(object_, address_, scratch1_, scratch0_));

      ASSERT(!AreAliased(object_orig_, address_, scratch1_, scratch0_));

      ASSERT(!AreAliased(object_, address_orig_, scratch1_, scratch0_));

      // We don't have to save scratch0_orig_ because it was given to us as

      // a scratch register.  But if we had to switch to a different reg then

      // we should save the new scratch0_.

      if (!scratch0_.is(scratch0_orig_)) masm->push(scratch0_);

      if (!rcx.is(scratch0_orig_) &&

          !rcx.is(object_orig_) &&

          !rcx.is(address_orig_)) {

        masm->push(rcx);

      }

      masm->push(scratch1_);

      if (!address_.is(address_orig_)) {

        masm->push(address_);

        masm->movq(address_, address_orig_);

      }

      if (!object_.is(object_orig_)) {

        masm->push(object_);

        masm->movq(object_, object_orig_);

      }

    }

    void Restore(MacroAssembler* masm) {

      // These will have been preserved the entire time, so we just need to move

      // them back.  Only in one case is the orig_ reg different from the plain

      // one, since only one of them can alias with rcx.

      if (!object_.is(object_orig_)) {

        masm->movq(object_orig_, object_);

        masm->pop(object_);

      }

      if (!address_.is(address_orig_)) {

        masm->movq(address_orig_, address_);

        masm->pop(address_);

      }

      masm->pop(scratch1_);

      if (!rcx.is(scratch0_orig_) &&

          !rcx.is(object_orig_) &&

          !rcx.is(address_orig_)) {

        masm->pop(rcx);

      }

      if (!scratch0_.is(scratch0_orig_)) masm->pop(scratch0_);

    }

    // If we have to call into C then we need to save and restore all caller-

    // saved registers that were not already preserved.

    // The three scratch registers (incl. rcx) will be restored by other means

    // so we don't bother pushing them here.  Rbx, rbp and r12-15 are callee

    // save and don't need to be preserved.

    void SaveCallerSaveRegisters(MacroAssembler* masm, SaveFPRegsMode mode) {

      masm->PushCallerSaved(mode, scratch0_, scratch1_, rcx);

    }

    inline void RestoreCallerSaveRegisters(MacroAssembler*masm,

                                           SaveFPRegsMode mode) {

      masm->PopCallerSaved(mode, scratch0_, scratch1_, rcx);

    }

    inline Register object() { return object_; }

    inline Register address() { return address_; }

    inline Register scratch0() { return scratch0_; }

    inline Register scratch1() { return scratch1_; }

   private:

    Register object_orig_;

    Register address_orig_;

    Register scratch0_orig_;

    Register object_;

    Register address_;

    Register scratch0_;

    Register scratch1_;

    // Third scratch register is always rcx.

    Register GetRegThatIsNotRcxOr(Register r1,

                                  Register r2,

                                  Register r3) {

      for (int i = 0; i < Register::NumAllocatableRegisters(); i++) {

        Register candidate = Register::FromAllocationIndex(i);

        if (candidate.is(rcx)) continue;

        if (candidate.is(r1)) continue;

        if (candidate.is(r2)) continue;

        if (candidate.is(r3)) continue;

        return candidate;

      }

      UNREACHABLE();

      return no_reg;

    }

    friend class RecordWriteStub;

  };

  enum OnNoNeedToInformIncrementalMarker {

    kReturnOnNoNeedToInformIncrementalMarker,

    kUpdateRememberedSetOnNoNeedToInformIncrementalMarker

  };

  void Generate(MacroAssembler* masm);

  void GenerateIncremental(MacroAssembler* masm, Mode mode);

  void CheckNeedsToInformIncrementalMarker(

      MacroAssembler* masm,

      OnNoNeedToInformIncrementalMarker on_no_need,

      Mode mode);

  void InformIncrementalMarker(MacroAssembler* masm, Mode mode);

  Major MajorKey() { return RecordWrite; }

  int MinorKey() {

    return ObjectBits::encode(object_.code()) |

        ValueBits::encode(value_.code()) |

        AddressBits::encode(address_.code()) |

        RememberedSetActionBits::encode(remembered_set_action_) |

        SaveFPRegsModeBits::encode(save_fp_regs_mode_);

  }

  void Activate(Code* code) {

    code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);

  }

  class ObjectBits: public BitField<int, 0, 4> {};

  class ValueBits: public BitField<int, 4, 4> {};

  class AddressBits: public BitField<int, 8, 4> {};

  class RememberedSetActionBits: public BitField<RememberedSetAction, 12, 1> {};

  class SaveFPRegsModeBits: public BitField<SaveFPRegsMode, 13, 1> {};

  Register object_;

  Register value_;

  Register address_;

  RememberedSetAction remembered_set_action_;

  SaveFPRegsMode save_fp_regs_mode_;

  Label slow_;

  RegisterAllocation regs_;

};

} }  // namespace v8::internal

#endif  // V8_X64_CODE_STUBS_X64_H_