text: // Copyright (c) 1994-2006 Sun Microsystems Inc.
  // 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.
  //
  // - Redistribution 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 Sun Microsystems or the names of 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.
  
  // The original source code covered by the above license above has been
  // modified significantly by Google Inc.
  // Copyright 2011 the V8 project authors. All rights reserved.
  
  #include "v8.h"
  
  #include "arguments.h"
  #include "deoptimizer.h"
  #include "execution.h"
  #include "ic-inl.h"
  #include "incremental-marking.h"
  #include "factory.h"
  #include "runtime.h"
  #include "runtime-profiler.h"
  #include "serialize.h"
  #include "stub-cache.h"
  #include "regexp-stack.h"
  #include "ast.h"
  #include "regexp-macro-assembler.h"
  #include "platform.h"
  #include "store-buffer.h"
  // Include native regexp-macro-assembler.
  #ifndef V8_INTERPRETED_REGEXP
  #if V8_TARGET_ARCH_IA32
  #include "ia32/regexp-macro-assembler-ia32.h"
  #elif V8_TARGET_ARCH_X64
  #include "x64/regexp-macro-assembler-x64.h"
  #elif V8_TARGET_ARCH_ARM
  #include "arm/regexp-macro-assembler-arm.h"
  #elif V8_TARGET_ARCH_MIPS
  #include "mips/regexp-macro-assembler-mips.h"
  #else  // Unknown architecture.
  #error "Unknown architecture."
  #endif  // Target architecture.
  #endif  // V8_INTERPRETED_REGEXP
  
  namespace v8 {
  namespace internal {
  
  
  const double DoubleConstant::min_int = kMinInt;
  const double DoubleConstant::one_half = 0.5;
  const double DoubleConstant::minus_zero = -0.0;
  const double DoubleConstant::uint8_max_value = 255;
  const double DoubleConstant::zero = 0.0;
  const double DoubleConstant::canonical_non_hole_nan = OS::nan_value();
  const double DoubleConstant::the_hole_nan = BitCast<double>(kHoleNanInt64);
  const double DoubleConstant::negative_infinity = -V8_INFINITY;
  const char* const RelocInfo::kFillerCommentString = "DEOPTIMIZATION PADDING";
  
  // -----------------------------------------------------------------------------
  // Implementation of AssemblerBase
  
  AssemblerBase::AssemblerBase(Isolate* isolate)
      : isolate_(isolate),
        jit_cookie_(0) {
    if (FLAG_mask_constants_with_cookie && isolate != NULL)  {
      jit_cookie_ = V8::RandomPrivate(isolate);
    }
  }
  
  
  // -----------------------------------------------------------------------------
  // Implementation of Label
  
  int Label::pos() const {
    if (pos_ < 0) return -pos_ - 1;
    if (pos_ > 0) return  pos_ - 1;
    UNREACHABLE();
    return 0;
  }
  
  
  // -----------------------------------------------------------------------------
  // Implementation of RelocInfoWriter and RelocIterator
  //
  // Relocation information is written backwards in memory, from high addresses
  // towards low addresses, byte by byte.  Therefore, in the encodings listed
  // below, the first byte listed it at the highest address, and successive
  // bytes in the record are at progressively lower addresses.
  //
  // Encoding
  //
  // The most common modes are given single-byte encodings.  Also, it is
  // easy to identify the type of reloc info and skip unwanted modes in
  // an iteration.
  //
  // The encoding relies on the fact that there are fewer than 14
  // different non-compactly encoded relocation modes.
  //
  // The first byte of a relocation record has a tag in its low 2 bits:
  // Here are the record schemes, depending on the low tag and optional higher
  // tags.
  //
  // Low tag:
  //   00: embedded_object:      [6-bit pc delta] 00
  //
  //   01: code_target:          [6-bit pc delta] 01
  //
  //   10: short_data_record:    [6-bit pc delta] 10 followed by
  //                             [6-bit data delta] [2-bit data type tag]
  //
  //   11: long_record           [2-bit high tag][4 bit middle_tag] 11
  //                             followed by variable data depending on type.
  //
  //  2-bit data type tags, used in short_data_record and data_jump long_record:
  //   code_target_with_id: 00
  //   position:            01
  //   statement_position:  10
  //   comment:             11 (not used in short_data_record)
  //
  //  Long record format:
  //    4-bit middle_tag:
  //      0000 - 1100 : Short record for RelocInfo::Mode middle_tag + 2
  //         (The middle_tag encodes rmode - RelocInfo::LAST_COMPACT_ENUM,
  //          and is between 0000 and 1100)
  //        The format is:
  //                              00 [4 bit middle_tag] 11 followed by
  //                              00 [6 bit pc delta]
  //
  //      1101: not used (would allow one more relocation mode to be added)
  //      1110: long_data_record
  //        The format is:       [2-bit data_type_tag] 1110 11
  //                             signed intptr_t, lowest byte written first
  //                             (except data_type code_target_with_id, which
  //                             is followed by a signed int, not intptr_t.)
  //
  //      1111: long_pc_jump
  //        The format is:
  //          pc-jump:             00 1111 11,
  //                               00 [6 bits pc delta]
  //        or
  //          pc-jump (variable length):
  //                               01 1111 11,
  //                               [7 bits data] 0
  //                                  ...
  //                               [7 bits data] 1
  //               (Bits 6..31 of pc delta, with leading zeroes
  //                dropped, and last non-zero chunk tagged with 1.)
  
  
  const int kMaxRelocModes = 14;
  
  const int kTagBits = 2;
  const int kTagMask = (1 << kTagBits) - 1;
  const int kExtraTagBits = 4;
  const int kLocatableTypeTagBits = 2;
  const int kSmallDataBits = kBitsPerByte - kLocatableTypeTagBits;
  
  const int kEmbeddedObjectTag = 0;
  const int kCodeTargetTag = 1;
  const int kLocatableTag = 2;
  const int kDefaultTag = 3;
  
  const int kPCJumpExtraTag = (1 << kExtraTagBits) - 1;
  
  const int kSmallPCDeltaBits = kBitsPerByte - kTagBits;
  const int kSmallPCDeltaMask = (1 << kSmallPCDeltaBits) - 1;
  const int RelocInfo::kMaxSmallPCDelta = kSmallPCDeltaMask;
  
  const int kVariableLengthPCJumpTopTag = 1;
  const int kChunkBits = 7;
  const int kChunkMask = (1 << kChunkBits) - 1;
  const int kLastChunkTagBits = 1;
  const int kLastChunkTagMask = 1;
  const int kLastChunkTag = 1;
  
  
  const int kDataJumpExtraTag = kPCJumpExtraTag - 1;
  
  const int kCodeWithIdTag = 0;
  const int kNonstatementPositionTag = 1;
  const int kStatementPositionTag = 2;
  const int kCommentTag = 3;
  
  
  uint32_t RelocInfoWriter::WriteVariableLengthPCJump(uint32_t pc_delta) {
    // Return if the pc_delta can fit in kSmallPCDeltaBits bits.
    // Otherwise write a variable length PC jump for the bits that do
    // not fit in the kSmallPCDeltaBits bits.
    if (is_uintn(pc_delta, kSmallPCDeltaBits)) return pc_delta;
    WriteExtraTag(kPCJumpExtraTag, kVariableLengthPCJumpTopTag);
    uint32_t pc_jump = pc_delta >> kSmallPCDeltaBits;
    ASSERT(pc_jump > 0);
    // Write kChunkBits size chunks of the pc_jump.
    for (; pc_jump > 0; pc_jump = pc_jump >> kChunkBits) {
      byte b = pc_jump & kChunkMask;
      *--pos_ = b << kLastChunkTagBits;
    }
    // Tag the last chunk so it can be identified.
    *pos_ = *pos_ | kLastChunkTag;
    // Return the remaining kSmallPCDeltaBits of the pc_delta.
    return pc_delta & kSmallPCDeltaMask;
  }
  
  
  void RelocInfoWriter::WriteTaggedPC(uint32_t pc_delta, int tag) {
    // Write a byte of tagged pc-delta, possibly preceded by var. length pc-jump.
    pc_delta = WriteVariableLengthPCJump(pc_delta);
    *--pos_ = pc_delta << kTagBits | tag;
  }
  
  
  void RelocInfoWriter::WriteTaggedData(intptr_t data_delta, int tag) {
    *--pos_ = static_cast<byte>(data_delta << kLocatableTypeTagBits | tag);
  }
  
  
  void RelocInfoWriter::WriteExtraTag(int extra_tag, int top_tag) {
    *--pos_ = static_cast<int>(top_tag << (kTagBits + kExtraTagBits) |
                               extra_tag << kTagBits |
                               kDefaultTag);
  }
  
  
  void RelocInfoWriter::WriteExtraTaggedPC(uint32_t pc_delta, int extra_tag) {
    // Write two-byte tagged pc-delta, possibly preceded by var. length pc-jump.
    pc_delta = WriteVariableLengthPCJump(pc_delta);
    WriteExtraTag(extra_tag, 0);
    *--pos_ = pc_delta;
  }
  
  
  void RelocInfoWriter::WriteExtraTaggedIntData(int data_delta, int top_tag) {
    WriteExtraTag(kDataJumpExtraTag, top_tag);
    for (int i = 0; i < kIntSize; i++) {
      *--pos_ = static_cast<byte>(data_delta);
      // Signed right shift is arithmetic shift.  Tested in test-utils.cc.
      data_delta = data_delta >> kBitsPerByte;
    }
  }
  
  void RelocInfoWriter::WriteExtraTaggedData(intptr_t data_delta, int top_tag) {
    WriteExtraTag(kDataJumpExtraTag, top_tag);
    for (int i = 0; i < kIntptrSize; i++) {
      *--pos_ = static_cast<byte>(data_delta);
      // Signed right shift is arithmetic shift.  Tested in test-utils.cc.
      data_delta = data_delta >> kBitsPerByte;
    }
  }
  
  
  void RelocInfoWriter::Write(const RelocInfo* rinfo) {
  #ifdef DEBUG
    byte* begin_pos = pos_;
  #endif
    ASSERT(rinfo->pc() - last_pc_ >= 0);
    ASSERT(RelocInfo::NUMBER_OF_MODES - RelocInfo::LAST_COMPACT_ENUM <=
           kMaxRelocModes);
    // Use unsigned delta-encoding for pc.
    uint32_t pc_delta = static_cast<uint32_t>(rinfo->pc() - last_pc_);
    RelocInfo::Mode rmode = rinfo->rmode();
  
    // The two most common modes are given small tags, and usually fit in a byte.
    if (rmode == RelocInfo::EMBEDDED_OBJECT) {
      WriteTaggedPC(pc_delta, kEmbeddedObjectTag);
    } else if (rmode == RelocInfo::CODE_TARGET) {
      WriteTaggedPC(pc_delta, kCodeTargetTag);
      ASSERT(begin_pos - pos_ <= RelocInfo::kMaxCallSize);
    } else if (rmode == RelocInfo::CODE_TARGET_WITH_ID) {
      // Use signed delta-encoding for id.
      ASSERT(static_cast<int>(rinfo->data()) == rinfo->data());
      int id_delta = static_cast<int>(rinfo->data()) - last_id_;
      // Check if delta is small enough to fit in a tagged byte.
      if (is_intn(id_delta, kSmallDataBits)) {
        WriteTaggedPC(pc_delta, kLocatableTag);
        WriteTaggedData(id_delta, kCodeWithIdTag);
      } else {
        // Otherwise, use costly encoding.
        WriteExtraTaggedPC(pc_delta, kPCJumpExtraTag);
        WriteExtraTaggedIntData(id_delta, kCodeWithIdTag);
      }
      last_id_ = static_cast<int>(rinfo->data());
    } else if (RelocInfo::IsPosition(rmode)) {
      // Use signed delta-encoding for position.
      ASSERT(static_cast<int>(rinfo->data()) == rinfo->data());
      int pos_delta = static_cast<int>(rinfo->data()) - last_position_;
      int pos_type_tag = (rmode == RelocInfo::POSITION) ? kNonstatementPositionTag
                                                        : kStatementPositionTag;
      // Check if delta is small enough to fit in a tagged byte.
      if (is_intn(pos_delta, kSmallDataBits)) {
        WriteTaggedPC(pc_delta, kLocatableTag);
        WriteTaggedData(pos_delta, pos_type_tag);
      } else {
        // Otherwise, use costly encoding.
        WriteExtraTaggedPC(pc_delta, kPCJumpExtraTag);
        WriteExtraTaggedIntData(pos_delta, pos_type_tag);
      }
      last_position_ = static_cast<int>(rinfo->data());
    } else if (RelocInfo::IsComment(rmode)) {
      // Comments are normally not generated, so we use the costly encoding.
      WriteExtraTaggedPC(pc_delta, kPCJumpExtraTag);
      WriteExtraTaggedData(rinfo->data(), kCommentTag);
      ASSERT(begin_pos - pos_ >= RelocInfo::kMinRelocCommentSize);
    } else {
      ASSERT(rmode > RelocInfo::LAST_COMPACT_ENUM);
      int saved_mode = rmode - RelocInfo::LAST_COMPACT_ENUM;
      // For all other modes we simply use the mode as the extra tag.
      // None of these modes need a data component.
      ASSERT(saved_mode < kPCJumpExtraTag && saved_mode < kDataJumpExtraTag);
      WriteExtraTaggedPC(pc_delta, saved_mode);
    }
    last_pc_ = rinfo->pc();
  #ifdef DEBUG
    ASSERT(begin_pos - pos_ <= kMaxSize);
  #endif
  }
  
  
  inline int RelocIterator::AdvanceGetTag() {
    return *--pos_ & kTagMask;
  }
  
  
  inline int RelocIterator::GetExtraTag() {
    return (*pos_ >> kTagBits) & ((1 << kExtraTagBits) - 1);
  }
  
  
  inline int RelocIterator::GetTopTag() {
    return *pos_ >> (kTagBits + kExtraTagBits);
  }
  
  
  inline void RelocIterator::ReadTaggedPC() {
    rinfo_.pc_ += *pos_ >> kTagBits;
  }
  
  
  inline void RelocIterator::AdvanceReadPC() {
    rinfo_.pc_ += *--pos_;
  }
  
  
  void RelocIterator::AdvanceReadId() {
    int x = 0;
    for (int i = 0; i < kIntSize; i++) {
      x |= static_cast<int>(*--pos_) << i * kBitsPerByte;
    }
    last_id_ += x;
    rinfo_.data_ = last_id_;
  }
  
  
  void RelocIterator::AdvanceReadPosition() {
    int x = 0;
    for (int i = 0; i < kIntSize; i++) {
      x |= static_cast<int>(*--pos_) << i * kBitsPerByte;
    }
    last_position_ += x;
    rinfo_.data_ = last_position_;
  }
  
  
  void RelocIterator::AdvanceReadData() {
    intptr_t x = 0;
    for (int i = 0; i < kIntptrSize; i++) {
      x |= static_cast<intptr_t>(*--pos_) << i * kBitsPerByte;
    }
    rinfo_.data_ = x;
  }
  
  
  void RelocIterator::AdvanceReadVariableLengthPCJump() {
    // Read the 32-kSmallPCDeltaBits most significant bits of the
    // pc jump in kChunkBits bit chunks and shift them into place.
    // Stop when the last chunk is encountered.
    uint32_t pc_jump = 0;
    for (int i = 0; i < kIntSize; i++) {
      byte pc_jump_part = *--pos_;
      pc_jump |= (pc_jump_part >> kLastChunkTagBits) << i * kChunkBits;
      if ((pc_jump_part & kLastChunkTagMask) == 1) break;
    }
    // The least significant kSmallPCDeltaBits bits will be added
    // later.
    rinfo_.pc_ += pc_jump << kSmallPCDeltaBits;
  }
  
  
  inline int RelocIterator::GetLocatableTypeTag() {
    return *pos_ & ((1 << kLocatableTypeTagBits) - 1);
  }
  
  
  inline void RelocIterator::ReadTaggedId() {
    int8_t signed_b = *pos_;
    // Signed right shift is arithmetic shift.  Tested in test-utils.cc.
    last_id_ += signed_b >> kLocatableTypeTagBits;
    rinfo_.data_ = last_id_;
  }
  
  
  inline void RelocIterator::ReadTaggedPosition() {
    int8_t signed_b = *pos_;
    // Signed right shift is arithmetic shift.  Tested in test-utils.cc.
    last_position_ += signed_b >> kLocatableTypeTagBits;
    rinfo_.data_ = last_position_;
  }
  
  
  static inline RelocInfo::Mode GetPositionModeFromTag(int tag) {
    ASSERT(tag == kNonstatementPositionTag ||
           tag == kStatementPositionTag);
    return (tag == kNonstatementPositionTag) ?
           RelocInfo::POSITION :
           RelocInfo::STATEMENT_POSITION;
  }
  
  
  void RelocIterator::next() {
    ASSERT(!done());
    // Basically, do the opposite of RelocInfoWriter::Write.
    // Reading of data is as far as possible avoided for unwanted modes,
    // but we must always update the pc.
    //
    // We exit this loop by returning when we find a mode we want.
    while (pos_ > end_) {
      int tag = AdvanceGetTag();
      if (tag == kEmbeddedObjectTag) {
        ReadTaggedPC();
        if (SetMode(RelocInfo::EMBEDDED_OBJECT)) return;
      } else if (tag == kCodeTargetTag) {
        ReadTaggedPC();
        if (SetMode(RelocInfo::CODE_TARGET)) return;
      } else if (tag == kLocatableTag) {
        ReadTaggedPC();
        Advance();
        int locatable_tag = GetLocatableTypeTag();
        if (locatable_tag == kCodeWithIdTag) {
          if (SetMode(RelocInfo::CODE_TARGET_WITH_ID)) {
            ReadTaggedId();
            return;
          }
        } else {
          // Compact encoding is never used for comments,
          // so it must be a position.
          ASSERT(locatable_tag == kNonstatementPositionTag ||
                 locatable_tag == kStatementPositionTag);
          if (mode_mask_ & RelocInfo::kPositionMask) {
            ReadTaggedPosition();
            if (SetMode(GetPositionModeFromTag(locatable_tag))) return;
          }
        }
      } else {
        ASSERT(tag == kDefaultTag);
        int extra_tag = GetExtraTag();
        if (extra_tag == kPCJumpExtraTag) {
          int top_tag = GetTopTag();
          if (top_tag == kVariableLengthPCJumpTopTag) {
            AdvanceReadVariableLengthPCJump();
          } else {
            AdvanceReadPC();
          }
        } else if (extra_tag == kDataJumpExtraTag) {
          int locatable_tag = GetTopTag();
          if (locatable_tag == kCodeWithIdTag) {
            if (SetMode(RelocInfo::CODE_TARGET_WITH_ID)) {
              AdvanceReadId();
              return;
            }
            Advance(kIntSize);
          } else if (locatable_tag != kCommentTag) {
            ASSERT(locatable_tag == kNonstatementPositionTag ||
                   locatable_tag == kStatementPositionTag);
            if (mode_mask_ & RelocInfo::kPositionMask) {
              AdvanceReadPosition();
              if (SetMode(GetPositionModeFromTag(locatable_tag))) return;
            } else {
              Advance(kIntSize);
            }
          } else {
            ASSERT(locatable_tag == kCommentTag);
            if (SetMode(RelocInfo::COMMENT)) {
              AdvanceReadData();
              return;
            }
            Advance(kIntptrSize);
          }
        } else {
          AdvanceReadPC();
          int rmode = extra_tag + RelocInfo::LAST_COMPACT_ENUM;
          if (SetMode(static_cast<RelocInfo::Mode>(rmode))) return;
        }
      }
    }
    done_ = true;
  }
  
  
  RelocIterator::RelocIterator(Code* code, int mode_mask) {
    rinfo_.host_ = code;
    rinfo_.pc_ = code->instruction_start();
    rinfo_.data_ = 0;
    // Relocation info is read backwards.
    pos_ = code->relocation_start() + code->relocation_size();
    end_ = code->relocation_start();
    done_ = false;
    mode_mask_ = mode_mask;
    last_id_ = 0;
    last_position_ = 0;
    if (mode_mask_ == 0) pos_ = end_;
    next();
  }
  
  
  RelocIterator::RelocIterator(const CodeDesc& desc, int mode_mask) {
    rinfo_.pc_ = desc.buffer;
    rinfo_.data_ = 0;
    // Relocation info is read backwards.
    pos_ = desc.buffer + desc.buffer_size;
    end_ = pos_ - desc.reloc_size;
    done_ = false;
    mode_mask_ = mode_mask;
    last_id_ = 0;
    last_position_ = 0;
    if (mode_mask_ == 0) pos_ = end_;
    next();
  }
  
  
  // -----------------------------------------------------------------------------
  // Implementation of RelocInfo
  
  
  #ifdef ENABLE_DISASSEMBLER
  const char* RelocInfo::RelocModeName(RelocInfo::Mode rmode) {
    switch (rmode) {
      case RelocInfo::NONE:
        return "no reloc";
      case RelocInfo::EMBEDDED_OBJECT:
        return "embedded object";
      case RelocInfo::CONSTRUCT_CALL:
        return "code target (js construct call)";
      case RelocInfo::CODE_TARGET_CONTEXT:
        return "code target (context)";
      case RelocInfo::DEBUG_BREAK:
  #ifndef ENABLE_DEBUGGER_SUPPORT
        UNREACHABLE();
  #endif
        return "debug break";
      case RelocInfo::CODE_TARGET:
        return "code target";
      case RelocInfo::CODE_TARGET_WITH_ID:
        return "code target with id";
      case RelocInfo::GLOBAL_PROPERTY_CELL:
        return "global property cell";
      case RelocInfo::RUNTIME_ENTRY:
        return "runtime entry";
      case RelocInfo::JS_RETURN:
        return "js return";
      case RelocInfo::COMMENT:
        return "comment";
      case RelocInfo::POSITION:
        return "position";
      case RelocInfo::STATEMENT_POSITION:
        return "statement position";
      case RelocInfo::EXTERNAL_REFERENCE:
        return "external reference";
      case RelocInfo::INTERNAL_REFERENCE:
        return "internal reference";
      case RelocInfo::DEBUG_BREAK_SLOT:
  #ifndef ENABLE_DEBUGGER_SUPPORT
        UNREACHABLE();
  #endif
        return "debug break slot";
      case RelocInfo::NUMBER_OF_MODES:
        UNREACHABLE();
        return "number_of_modes";
    }
    return "unknown relocation type";
  }
  
  
  void RelocInfo::Print(FILE* out) {
    PrintF(out, "%p  %s", pc_, RelocModeName(rmode_));
    if (IsComment(rmode_)) {
      PrintF(out, "  (%s)", reinterpret_cast<char*>(data_));
    } else if (rmode_ == EMBEDDED_OBJECT) {
      PrintF(out, "  (");
      target_object()->ShortPrint(out);
      PrintF(out, ")");
    } else if (rmode_ == EXTERNAL_REFERENCE) {
      ExternalReferenceEncoder ref_encoder;
      PrintF(out, " (%s)  (%p)",
             ref_encoder.NameOfAddress(*target_reference_address()),
             *target_reference_address());
    } else if (IsCodeTarget(rmode_)) {
      Code* code = Code::GetCodeFromTargetAddress(target_address());
      PrintF(out, " (%s)  (%p)", Code::Kind2String(code->kind()),
             target_address());
      if (rmode_ == CODE_TARGET_WITH_ID) {
        PrintF(" (id=%d)", static_cast<int>(data_));
      }
    } else if (IsPosition(rmode_)) {
      PrintF(out, "  (%" V8_PTR_PREFIX "d)", data());
    } else if (rmode_ == RelocInfo::RUNTIME_ENTRY &&
               Isolate::Current()->deoptimizer_data() != NULL) {
      // Depotimization bailouts are stored as runtime entries.
      int id = Deoptimizer::GetDeoptimizationId(
          target_address(), Deoptimizer::EAGER);
      if (id != Deoptimizer::kNotDeoptimizationEntry) {
        PrintF(out, "  (deoptimization bailout %d)", id);
      }
    }
  
    PrintF(out, "\n");
  }
  #endif  // ENABLE_DISASSEMBLER
  
  
  #ifdef DEBUG
  void RelocInfo::Verify() {
    switch (rmode_) {
      case EMBEDDED_OBJECT:
        Object::VerifyPointer(target_object());
        break;
      case GLOBAL_PROPERTY_CELL:
        Object::VerifyPointer(target_cell());
        break;
      case DEBUG_BREAK:
  #ifndef ENABLE_DEBUGGER_SUPPORT
        UNREACHABLE();
        break;
  #endif
      case CONSTRUCT_CALL:
      case CODE_TARGET_CONTEXT:
      case CODE_TARGET_WITH_ID:
      case CODE_TARGET: {
        // convert inline target address to code object
        Address addr = target_address();
        ASSERT(addr != NULL);
        // Check that we can find the right code object.
        Code* code = Code::GetCodeFromTargetAddress(addr);
        Object* found = HEAP->FindCodeObject(addr);
        ASSERT(found->IsCode());
        ASSERT(code->address() == HeapObject::cast(found)->address());
        break;
      }
      case RUNTIME_ENTRY:
      case JS_RETURN:
      case COMMENT:
      case POSITION:
      case STATEMENT_POSITION:
      case EXTERNAL_REFERENCE:
      case INTERNAL_REFERENCE:
      case DEBUG_BREAK_SLOT:
      case NONE:
        break;
      case NUMBER_OF_MODES:
        UNREACHABLE();
        break;
    }
  }
  #endif  // DEBUG
  
  
  // -----------------------------------------------------------------------------
  // Implementation of ExternalReference
  
  ExternalReference::ExternalReference(Builtins::CFunctionId id, Isolate* isolate)
    : address_(Redirect(isolate, Builtins::c_function_address(id))) {}
  
  
  ExternalReference::ExternalReference(
      ApiFunction* fun,
      Type type = ExternalReference::BUILTIN_CALL,
      Isolate* isolate = NULL)
    : address_(Redirect(isolate, fun->address(), type)) {}
  
  
  ExternalReference::ExternalReference(Builtins::Name name, Isolate* isolate)
    : address_(isolate->builtins()->builtin_address(name)) {}
  
  
  ExternalReference::ExternalReference(Runtime::FunctionId id,
                                       Isolate* isolate)
    : address_(Redirect(isolate, Runtime::FunctionForId(id)->entry)) {}
  
  
  ExternalReference::ExternalReference(const Runtime::Function* f,
                                       Isolate* isolate)
    : address_(Redirect(isolate, f->entry)) {}
  
  
  ExternalReference ExternalReference::isolate_address() {
    return ExternalReference(Isolate::Current());
  }
  
  
  ExternalReference::ExternalReference(const IC_Utility& ic_utility,
                                       Isolate* isolate)
    : address_(Redirect(isolate, ic_utility.address())) {}
  
  #ifdef ENABLE_DEBUGGER_SUPPORT
  ExternalReference::ExternalReference(const Debug_Address& debug_address,
                                       Isolate* isolate)
    : address_(debug_address.address(isolate)) {}
  #endif
  
  ExternalReference::ExternalReference(StatsCounter* counter)
    : address_(reinterpret_cast<Address>(counter->GetInternalPointer())) {}
  
  
  ExternalReference::ExternalReference(Isolate::AddressId id, Isolate* isolate)
    : address_(isolate->get_address_from_id(id)) {}
  
  
  ExternalReference::ExternalReference(const SCTableReference& table_ref)
    : address_(table_ref.address()) {}
  
  
  ExternalReference ExternalReference::
      incremental_marking_record_write_function(Isolate* isolate) {
    return ExternalReference(Redirect(
        isolate,
        FUNCTION_ADDR(IncrementalMarking::RecordWriteFromCode)));
  }
  
  
  ExternalReference ExternalReference::
      incremental_evacuation_record_write_function(Isolate* isolate) {
    return ExternalReference(Redirect(
        isolate,
        FUNCTION_ADDR(IncrementalMarking::RecordWriteForEvacuationFromCode)));
  }
  
  
  ExternalReference ExternalReference::
      store_buffer_overflow_function(Isolate* isolate) {
    return ExternalReference(Redirect(
        isolate,
        FUNCTION_ADDR(StoreBuffer::StoreBufferOverflow)));
  }
  
  
  ExternalReference ExternalReference::flush_icache_function(Isolate* isolate) {
    return ExternalReference(Redirect(isolate, FUNCTION_ADDR(CPU::FlushICache)));
  }
  
  
  ExternalReference ExternalReference::perform_gc_function(Isolate* isolate) {
    return
        ExternalReference(Redirect(isolate, FUNCTION_ADDR(Runtime::PerformGC)));
  }
  
  
  ExternalReference ExternalReference::fill_heap_number_with_random_function(
      Isolate* isolate) {
    return ExternalReference(Redirect(
        isolate,
        FUNCTION_ADDR(V8::FillHeapNumberWithRandom)));
  }
  
  
  ExternalReference ExternalReference::delete_handle_scope_extensions(
      Isolate* isolate) {
    return ExternalReference(Redirect(
        isolate,
        FUNCTION_ADDR(HandleScope::DeleteExtensions)));
  }
  
  
  ExternalReference ExternalReference::random_uint32_function(
      Isolate* isolate) {
    return ExternalReference(Redirect(isolate, FUNCTION_ADDR(V8::Random)));
  }
  
  
  ExternalReference ExternalReference::transcendental_cache_array_address(
      Isolate* isolate) {
    return ExternalReference(
        isolate->transcendental_cache()->cache_array_address());
  }
  
  
  ExternalReference ExternalReference::new_deoptimizer_function(
      Isolate* isolate) {
    return ExternalReference(
        Redirect(isolate, FUNCTION_ADDR(Deoptimizer::New)));
  }
  
  
  ExternalReference ExternalReference::compute_output_frames_function(
      Isolate* isolate) {
    return ExternalReference(
        Redirect(isolate, FUNCTION_ADDR(Deoptimizer::ComputeOutputFrames)));
  }
  
  
  ExternalReference ExternalReference::keyed_lookup_cache_keys(Isolate* isolate) {
    return ExternalReference(isolate->keyed_lookup_cache()->keys_address());
  }
  
  
  ExternalReference ExternalReference::keyed_lookup_cache_field_offsets(
      Isolate* isolate) {
    return ExternalReference(
        isolate->keyed_lookup_cache()->field_offsets_address());
  }
  
  
  ExternalReference ExternalReference::roots_array_start(Isolate* isolate) {
    return ExternalReference(isolate->heap()->roots_array_start());
  }
  
  
  ExternalReference ExternalReference::address_of_stack_limit(Isolate* isolate) {
    return ExternalReference(isolate->stack_guard()->address_of_jslimit());
  }
  
  
  ExternalReference ExternalReference::address_of_real_stack_limit(
      Isolate* isolate) {
    return ExternalReference(isolate->stack_guard()->address_of_real_jslimit());
  }
  
  
  ExternalReference ExternalReference::address_of_regexp_stack_limit(
      Isolate* isolate) {
    return ExternalReference(isolate->regexp_stack()->limit_address());
  }
  
  
  ExternalReference ExternalReference::new_space_start(Isolate* isolate) {
    return ExternalReference(isolate->heap()->NewSpaceStart());
  }
  
  
  ExternalReference ExternalReference::store_buffer_top(Isolate* isolate) {
    return ExternalReference(isolate->heap()->store_buffer()->TopAddress());
  }
  
  
  ExternalReference ExternalReference::new_space_mask(Isolate* isolate) {
    return ExternalReference(reinterpret_cast<Address>(
        isolate->heap()->NewSpaceMask()));
  }
  
  
  ExternalReference ExternalReference::new_space_allocation_top_address(
      Isolate* isolate) {
    return ExternalReference(isolate->heap()->NewSpaceAllocationTopAddress());
  }
  
  
  ExternalReference ExternalReference::heap_always_allocate_scope_depth(
      Isolate* isolate) {
    Heap* heap = isolate->heap();
    return ExternalReference(heap->always_allocate_scope_depth_address());
  }
  
  
  ExternalReference ExternalReference::new_space_allocation_limit_address(
      Isolate* isolate) {
    return ExternalReference(isolate->heap()->NewSpaceAllocationLimitAddress());
  }
  
  
  ExternalReference ExternalReference::handle_scope_level_address() {
    return ExternalReference(HandleScope::current_level_address());
  }
  
  
  ExternalReference ExternalReference::handle_scope_next_address() {
    return ExternalReference(HandleScope::current_next_address());
  }
  
  
  ExternalReference ExternalReference::handle_scope_limit_address() {
    return ExternalReference(HandleScope::current_limit_address());
  }
  
  
  ExternalReference ExternalReference::scheduled_exception_address(
      Isolate* isolate) {
    return ExternalReference(isolate->scheduled_exception_address());
  }
  
  
  ExternalReference ExternalReference::address_of_min_int() {
    return ExternalReference(reinterpret_cast<void*>(
        const_cast<double*>(&DoubleConstant::min_int)));
  }
  
  
  ExternalReference ExternalReference::address_of_one_half() {
    return ExternalReference(reinterpret_cast<void*>(
        const_cast<double*>(&DoubleConstant::one_half)));
  }
  
  
  ExternalReference ExternalReference::address_of_minus_zero() {
    return ExternalReference(reinterpret_cast<void*>(
        const_cast<double*>(&DoubleConstant::minus_zero)));
  }
  
  
  ExternalReference ExternalReference::address_of_zero() {
    return ExternalReference(reinterpret_cast<void*>(
        const_cast<double*>(&DoubleConstant::zero)));
  }
  
  
  ExternalReference ExternalReference::address_of_uint8_max_value() {
    return ExternalReference(reinterpret_cast<void*>(
        const_cast<double*>(&DoubleConstant::uint8_max_value)));
  }
  
  
  ExternalReference ExternalReference::address_of_negative_infinity() {
    return ExternalReference(reinterpret_cast<void*>(
        const_cast<double*>(&DoubleConstant::negative_infinity)));
  }
  
  
  ExternalReference ExternalReference::address_of_canonical_non_hole_nan() {
    return ExternalReference(reinterpret_cast<void*>(
        const_cast<double*>(&DoubleConstant::canonical_non_hole_nan)));
  }
  
  
  ExternalReference ExternalReference::address_of_the_hole_nan() {
    return ExternalReference(reinterpret_cast<void*>(
        const_cast<double*>(&DoubleConstant::the_hole_nan)));
  }
  
  
  #ifndef V8_INTERPRETED_REGEXP
  
  ExternalReference ExternalReference::re_check_stack_guard_state(
      Isolate* isolate) {
    Address function;
  #ifdef V8_TARGET_ARCH_X64
    function = FUNCTION_ADDR(RegExpMacroAssemblerX64::CheckStackGuardState);
  #elif V8_TARGET_ARCH_IA32
    function = FUNCTION_ADDR(RegExpMacroAssemblerIA32::CheckStackGuardState);
  #elif V8_TARGET_ARCH_ARM
    function = FUNCTION_ADDR(RegExpMacroAssemblerARM::CheckStackGuardState);
  #elif V8_TARGET_ARCH_MIPS
    function = FUNCTION_ADDR(RegExpMacroAssemblerMIPS::CheckStackGuardState);
  #else
    UNREACHABLE();
  #endif
    return ExternalReference(Redirect(isolate, function));
  }
  
  ExternalReference ExternalReference::re_grow_stack(Isolate* isolate) {
    return ExternalReference(
        Redirect(isolate, FUNCTION_ADDR(NativeRegExpMacroAssembler::GrowStack)));
  }
  
  ExternalReference ExternalReference::re_case_insensitive_compare_uc16(
      Isolate* isolate) {
    return ExternalReference(Redirect(
        isolate,
        FUNCTION_ADDR(NativeRegExpMacroAssembler::CaseInsensitiveCompareUC16)));
  }
  
  ExternalReference ExternalReference::re_word_character_map() {
    return ExternalReference(
        NativeRegExpMacroAssembler::word_character_map_address());
  }
  
  ExternalReference ExternalReference::address_of_static_offsets_vector(
      Isolate* isolate) {
    return ExternalReference(
        OffsetsVector::static_offsets_vector_address(isolate));
  }
  
  ExternalReference ExternalReference::address_of_regexp_stack_memory_address(
      Isolate* isolate) {
    return ExternalReference(
        isolate->regexp_stack()->memory_address());
  }
  
  ExternalReference ExternalReference::address_of_regexp_stack_memory_size(
      Isolate* isolate) {
    return ExternalReference(isolate->regexp_stack()->memory_size_address());
  }
  
  #endif  // V8_INTERPRETED_REGEXP
  
  
  static double add_two_doubles(double x, double y) {
    return x + y;
  }
  
  
  static double sub_two_doubles(double x, double y) {
    return x - y;
  }
  
  
  static double mul_two_doubles(double x, double y) {
    return x * y;
  }
  
  
  static double div_two_doubles(double x, double y) {
    return x / y;
  }
  
  
  static double mod_two_doubles(double x, double y) {
    return modulo(x, y);
  }
  
  
  static double math_sin_double(double x) {
    return sin(x);
  }
  
  
  static double math_cos_double(double x) {
    return cos(x);
  }
  
  
  static double math_tan_double(double x) {
    return tan(x);
  }
  
  
  static double math_log_double(double x) {
    return log(x);
  }
  
  
  ExternalReference ExternalReference::math_sin_double_function(
      Isolate* isolate) {
    return ExternalReference(Redirect(isolate,
                                      FUNCTION_ADDR(math_sin_double),
                                      BUILTIN_FP_CALL));
  }
  
  
  ExternalReference ExternalReference::math_cos_double_function(
      Isolate* isolate) {
    return ExternalReference(Redirect(isolate,
                                      FUNCTION_ADDR(math_cos_double),
                                      BUILTIN_FP_CALL));
  }
  
  
  ExternalReference ExternalReference::math_tan_double_function(
      Isolate* isolate) {
    return ExternalReference(Redirect(isolate,
                                      FUNCTION_ADDR(math_tan_double),
                                      BUILTIN_FP_CALL));
  }
  
  
  ExternalReference ExternalReference::math_log_double_function(
      Isolate* isolate) {
    return ExternalReference(Redirect(isolate,
                                      FUNCTION_ADDR(math_log_double),
                                      BUILTIN_FP_CALL));
  }
  
  
  // Helper function to compute x^y, where y is known to be an
  // integer. Uses binary decomposition to limit the number of
  // multiplications; see the discussion in "Hacker's Delight" by Henry
  // S. Warren, Jr., figure 11-6, page 213.
  double power_double_int(double x, int y) {
    double m = (y < 0) ? 1 / x : x;
    unsigned n = (y < 0) ? -y : y;
    double p = 1;
    while (n != 0) {
      if ((n & 1) != 0) p *= m;
      m *= m;
      if ((n & 2) != 0) p *= m;
      m *= m;
      n >>= 2;
    }
    return p;
  }
  
  
  double power_double_double(double x, double y) {
    // The checks for special cases can be dropped in ia32 because it has already
    // been done in generated code before bailing out here.
    if (isnan(y) || ((x == 1 || x == -1) && isinf(y))) return OS::nan_value();
    return pow(x, y);
  }
  
  
  ExternalReference ExternalReference::power_double_double_function(
      Isolate* isolate) {
    return ExternalReference(Redirect(isolate,
                                      FUNCTION_ADDR(power_double_double),
                                      BUILTIN_FP_FP_CALL));
  }
  
  
  ExternalReference ExternalReference::power_double_int_function(
      Isolate* isolate) {
    return ExternalReference(Redirect(isolate,
                                      FUNCTION_ADDR(power_double_int),
                                      BUILTIN_FP_INT_CALL));
  }
  
  
  static int native_compare_doubles(double y, double x) {
    if (x == y) return EQUAL;
    return x < y ? LESS : GREATER;
  }
  
  
  bool EvalComparison(Token::Value op, double op1, double op2) {
    ASSERT(Token::IsCompareOp(op));
    switch (op) {
      case Token::EQ:
      case Token::EQ_STRICT: return (op1 == op2);
      case Token::NE: return (op1 != op2);
      case Token::LT: return (op1 < op2);
      case Token::GT: return (op1 > op2);
      case Token::LTE: return (op1 <= op2);
      case Token::GTE: return (op1 >= op2);
      default:
        UNREACHABLE();
        return false;
    }
  }
  
  
  ExternalReference ExternalReference::double_fp_operation(
      Token::Value operation, Isolate* isolate) {
    typedef double BinaryFPOperation(double x, double y);
    BinaryFPOperation* function = NULL;
    switch (operation) {
      case Token::ADD:
        function = &add_two_doubles;
        break;
      case Token::SUB:
        function = &sub_two_doubles;
        break;
      case Token::MUL:
        function = &mul_two_doubles;
        break;
      case Token::DIV:
        function = &div_two_doubles;
        break;
      case Token::MOD:
        function = &mod_two_doubles;
        break;
      default:
        UNREACHABLE();
    }
    return ExternalReference(Redirect(isolate,
                                      FUNCTION_ADDR(function),
                                      BUILTIN_FP_FP_CALL));
  }
  
  
  ExternalReference ExternalReference::compare_doubles(Isolate* isolate) {
    return ExternalReference(Redirect(isolate,
                                      FUNCTION_ADDR(native_compare_doubles),
                                      BUILTIN_COMPARE_CALL));
  }
  
  
  #ifdef ENABLE_DEBUGGER_SUPPORT
  ExternalReference ExternalReference::debug_break(Isolate* isolate) {
    return ExternalReference(Redirect(isolate, FUNCTION_ADDR(Debug_Break)));
  }
  
  
  ExternalReference ExternalReference::debug_step_in_fp_address(
      Isolate* isolate) {
    return ExternalReference(isolate->debug()->step_in_fp_addr());
  }
  #endif
  
  
  void PositionsRecorder::RecordPosition(int pos) {
    ASSERT(pos != RelocInfo::kNoPosition);
    ASSERT(pos >= 0);
    state_.current_position = pos;
  #ifdef ENABLE_GDB_JIT_INTERFACE
    if (gdbjit_lineinfo_ != NULL) {
      gdbjit_lineinfo_->SetPosition(assembler_->pc_offset(), pos, false);
    }
  #endif
  }
  
  
  void PositionsRecorder::RecordStatementPosition(int pos) {
    ASSERT(pos != RelocInfo::kNoPosition);
    ASSERT(pos >= 0);
    state_.current_statement_position = pos;
  #ifdef ENABLE_GDB_JIT_INTERFACE
    if (gdbjit_lineinfo_ != NULL) {
      gdbjit_lineinfo_->SetPosition(assembler_->pc_offset(), pos, true);
    }
  #endif
  }
  
  
  bool PositionsRecorder::WriteRecordedPositions() {
    bool written = false;
  
    // Write the statement position if it is different from what was written last
    // time.
    if (state_.current_statement_position != state_.written_statement_position) {
      EnsureSpace ensure_space(assembler_);
      assembler_->RecordRelocInfo(RelocInfo::STATEMENT_POSITION,
                                  state_.current_statement_position);
      state_.written_statement_position = state_.current_statement_position;
      written = true;
    }
  
    // Write the position if it is different from what was written last time and
    // also different from the written statement position.
    if (state_.current_position != state_.written_position &&
        state_.current_position != state_.written_statement_position) {
      EnsureSpace ensure_space(assembler_);
      assembler_->RecordRelocInfo(RelocInfo::POSITION, state_.current_position);
      state_.written_position = state_.current_position;
      written = true;
    }
  
    // Return whether something was written.
    return written;
  }
  
  } }  // namespace v8::internal
  