assembler.cc.svn-base

Google浏览器V8内核代码

  return *pos_ & ((1 << kPositionTypeTagBits) - 1);
}


inline void RelocIterator::ReadTaggedData() {
  int8_t signed_b = *pos_;
  rinfo_.data_ += ArithmeticShiftRight(signed_b, kPositionTypeTagBits);
}


inline RelocInfo::Mode RelocIterator::DebugInfoModeFromTag(int tag) {
  if (tag == kStatementPositionTag) {
    return RelocInfo::STATEMENT_POSITION;
  } else if (tag == kNonstatementPositionTag) {
    return RelocInfo::POSITION;
  } else {
    ASSERT(tag == kCommentTag);
    return RelocInfo::COMMENT;
  }
}


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 (*(reinterpret_cast<int**>(rinfo_.pc())) ==
          reinterpret_cast<int*>(0x61)) {
        tag = 0;
      }
      if (SetMode(RelocInfo::CODE_TARGET)) return;
    } else if (tag == kPositionTag) {
      ReadTaggedPC();
      Advance();
      // Check if we want source positions.
      if (mode_mask_ & RelocInfo::kPositionMask) {
        // Check if we want this type of source position.
        if (SetMode(DebugInfoModeFromTag(GetPositionTypeTag()))) {
          // Finally read the data before returning.
          ReadTaggedData();
          return;
        }
      }
    } else {
      ASSERT(tag == kDefaultTag);
      int extra_tag = GetExtraTag();
      if (extra_tag == kPCJumpTag) {
        int top_tag = GetTopTag();
        if (top_tag == kVariableLengthPCJumpTopTag) {
          AdvanceReadVariableLengthPCJump();
        } else {
          AdvanceReadPC();
        }
      } else if (extra_tag == kDataJumpTag) {
        // Check if we want debug modes (the only ones with data).
        if (mode_mask_ & RelocInfo::kDebugMask) {
          int top_tag = GetTopTag();
          AdvanceReadData();
          if (SetMode(DebugInfoModeFromTag(top_tag))) return;
        } else {
          // Otherwise, just skip over the data.
          Advance(kIntSize);
        }
      } else {
        AdvanceReadPC();
        if (SetMode(static_cast<RelocInfo::Mode>(extra_tag))) return;
      }
    }
  }
  done_ = true;
}


RelocIterator::RelocIterator(Code* code, int mode_mask) {
  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;
  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;
  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::EMBEDDED_STRING:
      return "embedded string";
    case RelocInfo::CONSTRUCT_CALL:
      return "code target (js construct call)";
    case RelocInfo::CODE_TARGET_CONTEXT:
      return "code target (context)";
    case RelocInfo::CODE_TARGET:
      return "code target";
    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::NUMBER_OF_MODES:
      UNREACHABLE();
      return "number_of_modes";
  }
  return "unknown relocation type";
}


void RelocInfo::Print() {
  PrintF("%p  %s", pc_, RelocModeName(rmode_));
  if (IsComment(rmode_)) {
    PrintF("  (%s)", data_);
  } else if (rmode_ == EMBEDDED_OBJECT) {
    PrintF("  (");
    target_object()->ShortPrint();
    PrintF(")");
  } else if (rmode_ == EXTERNAL_REFERENCE) {
    ExternalReferenceEncoder ref_encoder;
    PrintF(" (%s)  (%p)",
           ref_encoder.NameOfAddress(*target_reference_address()),
           *target_reference_address());
  } else if (IsCodeTarget(rmode_)) {
    Code* code = Debug::GetCodeTarget(target_address());
    PrintF(" (%s)  (%p)", Code::Kind2String(code->kind()), target_address());
  } else if (IsPosition(rmode_)) {
    PrintF("  (%d)", data());
  }

  PrintF("\n");
}
#endif  // ENABLE_DISASSEMBLER


#ifdef DEBUG
void RelocInfo::Verify() {
  switch (rmode_) {
    case EMBEDDED_OBJECT:
      Object::VerifyPointer(target_object());
      break;
    case CONSTRUCT_CALL:
    case CODE_TARGET_CONTEXT:
    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.
      HeapObject* code = HeapObject::FromAddress(addr - Code::kHeaderSize);
      Object* found = Heap::FindCodeObject(addr);
      ASSERT(found->IsCode());
      ASSERT(code->address() == HeapObject::cast(found)->address());
      break;
    }
    case RelocInfo::EMBEDDED_STRING:
    case RUNTIME_ENTRY:
    case JS_RETURN:
    case COMMENT:
    case POSITION:
    case STATEMENT_POSITION:
    case EXTERNAL_REFERENCE:
    case INTERNAL_REFERENCE:
    case NONE:
      break;
    case NUMBER_OF_MODES:
      UNREACHABLE();
      break;
  }
}
#endif  // DEBUG


// -----------------------------------------------------------------------------
// Implementation of ExternalReference

ExternalReference::ExternalReference(Builtins::CFunctionId id)
  : address_(Builtins::c_function_address(id)) {}


ExternalReference::ExternalReference(Builtins::Name name)
  : address_(Builtins::builtin_address(name)) {}


ExternalReference::ExternalReference(Runtime::FunctionId id)
  : address_(Runtime::FunctionForId(id)->entry) {}


ExternalReference::ExternalReference(Runtime::Function* f)
  : address_(f->entry) {}


ExternalReference::ExternalReference(const IC_Utility& ic_utility)
  : address_(ic_utility.address()) {}


ExternalReference::ExternalReference(const Debug_Address& debug_address)
  : address_(debug_address.address()) {}


ExternalReference::ExternalReference(StatsCounter* counter)
  : address_(reinterpret_cast<Address>(counter->GetInternalPointer())) {}


ExternalReference::ExternalReference(Top::AddressId id)
  : address_(Top::get_address_from_id(id)) {}


ExternalReference::ExternalReference(const SCTableReference& table_ref)
  : address_(table_ref.address()) {}


ExternalReference ExternalReference::builtin_passed_function() {
  return ExternalReference(&Builtins::builtin_passed_function);
}

ExternalReference ExternalReference::the_hole_value_location() {
  return ExternalReference(Factory::the_hole_value().location());
}


ExternalReference ExternalReference::address_of_stack_guard_limit() {
  return ExternalReference(StackGuard::address_of_jslimit());
}


ExternalReference ExternalReference::debug_break() {
  return ExternalReference(FUNCTION_ADDR(Debug::Break));
}


ExternalReference ExternalReference::new_space_start() {
  return ExternalReference(Heap::NewSpaceStart());
}

ExternalReference ExternalReference::new_space_allocation_top_address() {
  return ExternalReference(Heap::NewSpaceAllocationTopAddress());
}

ExternalReference ExternalReference::new_space_allocation_limit_address() {
  return ExternalReference(Heap::NewSpaceAllocationLimitAddress());
}

ExternalReference ExternalReference::debug_step_in_fp_address() {
  return ExternalReference(Debug::step_in_fp_addr());
}

} }  // namespace v8::internal