macro-assembler-ia32.cc.svn-base

Google浏览器V8内核代码

  // expectation.
  if (f->nargs >= 0 && f->nargs != num_arguments) {
    IllegalOperation();
    return;
  }

  Runtime::FunctionId function_id =
      static_cast<Runtime::FunctionId>(f->stub_id);
  RuntimeStub stub(function_id, num_arguments);
  CallStub(&stub);
}


void MacroAssembler::TailCallRuntime(const ExternalReference& ext,
                                     int num_arguments) {
  // TODO(1236192): Most runtime routines don't need the number of
  // arguments passed in because it is constant. At some point we
  // should remove this need and make the runtime routine entry code
  // smarter.
  mov(Operand(eax), Immediate(num_arguments));
  JumpToBuiltin(ext);
}


void MacroAssembler::JumpToBuiltin(const ExternalReference& ext) {
  // Set the entry point and jump to the C entry runtime stub.
  mov(Operand(ebx), Immediate(ext));
  CEntryStub ces;
  jmp(ces.GetCode(), RelocInfo::CODE_TARGET);
}


void MacroAssembler::InvokePrologue(const ParameterCount& expected,
                                    const ParameterCount& actual,
                                    Handle<Code> code_constant,
                                    const Operand& code_operand,
                                    Label* done,
                                    InvokeFlag flag) {
  bool definitely_matches = false;
  Label invoke;
  if (expected.is_immediate()) {
    ASSERT(actual.is_immediate());
    if (expected.immediate() == actual.immediate()) {
      definitely_matches = true;
    } else {
      mov(eax, actual.immediate());
      const int sentinel = SharedFunctionInfo::kDontAdaptArgumentsSentinel;
      if (expected.immediate() == sentinel) {
        // Don't worry about adapting arguments for builtins that
        // don't want that done. Skip adaption code by making it look
        // like we have a match between expected and actual number of
        // arguments.
        definitely_matches = true;
      } else {
        mov(ebx, expected.immediate());
      }
    }
  } else {
    if (actual.is_immediate()) {
      // Expected is in register, actual is immediate. This is the
      // case when we invoke function values without going through the
      // IC mechanism.
      cmp(expected.reg(), actual.immediate());
      j(equal, &invoke);
      ASSERT(expected.reg().is(ebx));
      mov(eax, actual.immediate());
    } else if (!expected.reg().is(actual.reg())) {
      // Both expected and actual are in (different) registers. This
      // is the case when we invoke functions using call and apply.
      cmp(expected.reg(), Operand(actual.reg()));
      j(equal, &invoke);
      ASSERT(actual.reg().is(eax));
      ASSERT(expected.reg().is(ebx));
    }
  }

  if (!definitely_matches) {
    Handle<Code> adaptor =
        Handle<Code>(Builtins::builtin(Builtins::ArgumentsAdaptorTrampoline));
    if (!code_constant.is_null()) {
      mov(Operand(edx), Immediate(code_constant));
      add(Operand(edx), Immediate(Code::kHeaderSize - kHeapObjectTag));
    } else if (!code_operand.is_reg(edx)) {
      mov(edx, code_operand);
    }

    if (flag == CALL_FUNCTION) {
      call(adaptor, RelocInfo::CODE_TARGET);
      jmp(done);
    } else {
      jmp(adaptor, RelocInfo::CODE_TARGET);
    }
    bind(&invoke);
  }
}


void MacroAssembler::InvokeCode(const Operand& code,
                                const ParameterCount& expected,
                                const ParameterCount& actual,
                                InvokeFlag flag) {
  Label done;
  InvokePrologue(expected, actual, Handle<Code>::null(), code, &done, flag);
  if (flag == CALL_FUNCTION) {
    call(code);
  } else {
    ASSERT(flag == JUMP_FUNCTION);
    jmp(code);
  }
  bind(&done);
}


void MacroAssembler::InvokeCode(Handle<Code> code,
                                const ParameterCount& expected,
                                const ParameterCount& actual,
                                RelocInfo::Mode rmode,
                                InvokeFlag flag) {
  Label done;
  Operand dummy(eax);
  InvokePrologue(expected, actual, code, dummy, &done, flag);
  if (flag == CALL_FUNCTION) {
    call(code, rmode);
  } else {
    ASSERT(flag == JUMP_FUNCTION);
    jmp(code, rmode);
  }
  bind(&done);
}


void MacroAssembler::InvokeFunction(Register fun,
                                    const ParameterCount& actual,
                                    InvokeFlag flag) {
  ASSERT(fun.is(edi));
  mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
  mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
  mov(ebx, FieldOperand(edx, SharedFunctionInfo::kFormalParameterCountOffset));
  mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
  lea(edx, FieldOperand(edx, Code::kHeaderSize));

  ParameterCount expected(ebx);
  InvokeCode(Operand(edx), expected, actual, flag);
}


void MacroAssembler::InvokeBuiltin(Builtins::JavaScript id, InvokeFlag flag) {
  bool resolved;
  Handle<Code> code = ResolveBuiltin(id, &resolved);

    // Calls are not allowed in some stubs.
  ASSERT(flag == JUMP_FUNCTION || allow_stub_calls());

  // Rely on the assertion to check that the number of provided
  // arguments match the expected number of arguments. Fake a
  // parameter count to avoid emitting code to do the check.
  ParameterCount expected(0);
  InvokeCode(Handle<Code>(code), expected, expected,
             RelocInfo::CODE_TARGET, flag);

  const char* name = Builtins::GetName(id);
  int argc = Builtins::GetArgumentsCount(id);

  if (!resolved) {
    uint32_t flags =
        Bootstrapper::FixupFlagsArgumentsCount::encode(argc) |
        Bootstrapper::FixupFlagsIsPCRelative::encode(true);
    Unresolved entry = { pc_offset() - sizeof(int32_t), flags, name };
    unresolved_.Add(entry);
  }
}


void MacroAssembler::GetBuiltinEntry(Register target, Builtins::JavaScript id) {
  bool resolved;
  Handle<Code> code = ResolveBuiltin(id, &resolved);

  const char* name = Builtins::GetName(id);
  int argc = Builtins::GetArgumentsCount(id);

  mov(Operand(target), Immediate(code));
  if (!resolved) {
    uint32_t flags =
        Bootstrapper::FixupFlagsArgumentsCount::encode(argc) |
        Bootstrapper::FixupFlagsIsPCRelative::encode(false);
    Unresolved entry = { pc_offset() - sizeof(int32_t), flags, name };
    unresolved_.Add(entry);
  }
  add(Operand(target), Immediate(Code::kHeaderSize - kHeapObjectTag));
}


Handle<Code> MacroAssembler::ResolveBuiltin(Builtins::JavaScript id,
                                            bool* resolved) {
  // Move the builtin function into the temporary function slot by
  // reading it from the builtins object. NOTE: We should be able to
  // reduce this to two instructions by putting the function table in
  // the global object instead of the "builtins" object and by using a
  // real register for the function.
  mov(edx, Operand(esi, Context::SlotOffset(Context::GLOBAL_INDEX)));
  mov(edx, FieldOperand(edx, GlobalObject::kBuiltinsOffset));
  int builtins_offset =
      JSBuiltinsObject::kJSBuiltinsOffset + (id * kPointerSize);
  mov(edi, FieldOperand(edx, builtins_offset));


  return Builtins::GetCode(id, resolved);
}


void MacroAssembler::Ret() {
  ret(0);
}


void MacroAssembler::SetCounter(StatsCounter* counter, int value) {
  if (FLAG_native_code_counters && counter->Enabled()) {
    mov(Operand::StaticVariable(ExternalReference(counter)), Immediate(value));
  }
}


void MacroAssembler::IncrementCounter(StatsCounter* counter, int value) {
  ASSERT(value > 0);
  if (FLAG_native_code_counters && counter->Enabled()) {
    Operand operand = Operand::StaticVariable(ExternalReference(counter));
    if (value == 1) {
      inc(operand);
    } else {
      add(operand, Immediate(value));
    }
  }
}


void MacroAssembler::DecrementCounter(StatsCounter* counter, int value) {
  ASSERT(value > 0);
  if (FLAG_native_code_counters && counter->Enabled()) {
    Operand operand = Operand::StaticVariable(ExternalReference(counter));
    if (value == 1) {
      dec(operand);
    } else {
      sub(operand, Immediate(value));
    }
  }
}


void MacroAssembler::Assert(Condition cc, const char* msg) {
  if (FLAG_debug_code) Check(cc, msg);
}


void MacroAssembler::Check(Condition cc, const char* msg) {
  Label L;
  j(cc, &L, taken);
  Abort(msg);
  // will not return here
  bind(&L);
}


void MacroAssembler::Abort(const char* msg) {
  // We want to pass the msg string like a smi to avoid GC
  // problems, however msg is not guaranteed to be aligned
  // properly. Instead, we pass an aligned pointer that is
  // a proper v8 smi, but also pass the aligment difference
  // from the real pointer as a smi.
  intptr_t p1 = reinterpret_cast<intptr_t>(msg);
  intptr_t p0 = (p1 & ~kSmiTagMask) + kSmiTag;
  ASSERT(reinterpret_cast<Object*>(p0)->IsSmi());
#ifdef DEBUG
  if (msg != NULL) {
    RecordComment("Abort message: ");
    RecordComment(msg);
  }
#endif
  push(eax);
  push(Immediate(p0));
  push(Immediate(reinterpret_cast<intptr_t>(Smi::FromInt(p1 - p0))));
  CallRuntime(Runtime::kAbort, 2);
  // will not return here
}


CodePatcher::CodePatcher(byte* address, int size)
  : address_(address), size_(size), masm_(address, size + Assembler::kGap) {
  // Create a new macro assembler pointing to the assress of the code to patch.
  // The size is adjusted with kGap on order for the assembler to generate size
  // bytes of instructions without failing with buffer size constraints.
  ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
}


CodePatcher::~CodePatcher() {
  // Indicate that code has changed.
  CPU::FlushICache(address_, size_);

  // Check that the code was patched as expected.
  ASSERT(masm_.pc_ == address_ + size_);
  ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
}


} }  // namespace v8::internal