builtins.cc.svn-base

Google浏览器V8内核代码

// Copyright 2006-2008 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.

#include "v8.h"

#include "api.h"
#include "bootstrapper.h"
#include "builtins.h"
#include "ic-inl.h"

namespace v8 { namespace internal {

// ----------------------------------------------------------------------------
// Support macros for defining builtins in C.
// ----------------------------------------------------------------------------
//
// A builtin function is defined by writing:
//
//   BUILTIN(name) {
//     ...
//   }
//   BUILTIN_END
//
// In the body of the builtin function, the variable 'receiver' is visible.
// The arguments can be accessed through:
//
//   BUILTIN_ARG(0): Receiver (also available as 'receiver')
//   BUILTIN_ARG(1): First argument
//     ...
//   BUILTIN_ARG(n): Last argument
//
// and they evaluate to undefined values if too few arguments were
// passed to the builtin function invocation.
//
// __argc__ is the number of arguments including the receiver.
// ----------------------------------------------------------------------------


// TODO(1238487): We should consider passing whether or not the
// builtin was invoked as a constructor as part of the
// arguments. Maybe we also want to pass the called function?
#define BUILTIN(name)                                                   \
  static Object* Builtin_##name(int __argc__, Object** __argv__) {      \
    Handle<Object> receiver(&__argv__[0]);


// Use an inline function to avoid evaluating the index (n) more than
// once in the BUILTIN_ARG macro.
static inline Object* __builtin_arg__(int n, int argc, Object** argv) {
  ASSERT(n >= 0);
  return (argc > n) ? argv[-n] : Heap::undefined_value();
}


// NOTE: Argument 0 is the receiver. The first 'real' argument is
// argument 1 - BUILTIN_ARG(1).
#define BUILTIN_ARG(n) (__builtin_arg__(n, __argc__, __argv__))


#define BUILTIN_END                             \
  return Heap::undefined_value();               \
}


// TODO(1238487): Get rid of this function that determines if the
// builtin is called as a constructor. This may be a somewhat slow
// operation due to the stack frame iteration.
static inline bool CalledAsConstructor() {
  StackFrameIterator it;
  ASSERT(it.frame()->is_exit());
  it.Advance();
  StackFrame* frame = it.frame();
  return frame->is_internal() &&
      InternalFrame::cast(frame)->is_construct_trampoline();
}


// ----------------------------------------------------------------------------


int Builtins::construct_call_pc_offset_ = 0;
int Builtins::arguments_adaptor_call_pc_offset_ = 0;


// Check if the builtin was called in a 'new' call.
bool Builtins::IsConstructCall(Address pc) {
  ASSERT(construct_call_pc_offset_ > 0);
  int offset = pc - builtin(JSConstructCall)->address();
  return offset == construct_call_pc_offset_;
}


bool Builtins::IsArgumentsAdaptorCall(Address pc) {
  ASSERT(arguments_adaptor_call_pc_offset_ > 0);
  int offset = pc - builtin(ArgumentsAdaptorTrampoline)->address();
  return offset == arguments_adaptor_call_pc_offset_;
}


Handle<Code> Builtins::GetCode(JavaScript id, bool* resolved) {
  Code* code = Builtins::builtin(Builtins::Illegal);
  *resolved = false;

  if (Top::security_context() != NULL) {
    Object* object = Top::security_context_builtins()->javascript_builtin(id);
    if (object->IsJSFunction()) {
      Handle<JSFunction> function(JSFunction::cast(object));
      // Make sure the number of parameters match the formal parameter count.
      ASSERT(function->shared()->formal_parameter_count() ==
             Builtins::GetArgumentsCount(id));
      if (function->is_compiled() || CompileLazy(function, CLEAR_EXCEPTION)) {
        code = function->code();
        *resolved = true;
      }
    }
  }

  return Handle<Code>(code);
}


BUILTIN(Illegal) {
  UNREACHABLE();
}
BUILTIN_END


BUILTIN(EmptyFunction) {
}
BUILTIN_END


BUILTIN(ArrayCode) {
  JSArray* array;
  if (CalledAsConstructor()) {
    array = JSArray::cast(*receiver);
  } else {
    // Allocate the JS Array
    JSFunction* constructor =
        Top::context()->global_context()->array_function();
    Object* obj = Heap::AllocateJSObject(constructor);
    if (obj->IsFailure()) return obj;
    array = JSArray::cast(obj);
  }

  // 'array' now contains the JSArray we should initialize.

  // Optimize the case where there is one argument and the argument is a
  // small smi.
  if (__argc__ == 2) {
    Object* obj = BUILTIN_ARG(1);
    if (obj->IsSmi()) {
      int len = Smi::cast(obj)->value();
      if (len >= 0 && len < JSObject::kMaxFastElementsLength) {
        Object* obj = Heap::AllocateFixedArrayWithHoles(len);
        if (obj->IsFailure()) return obj;
        array->SetContent(FixedArray::cast(obj));
        return array;
      }
    }
    // Take the argument as the length.
    obj = array->Initialize(0);
    if (obj->IsFailure()) return obj;
    if (__argc__ == 2) return array->SetElementsLength(BUILTIN_ARG(1));
  }

  // Optimize the case where there are no parameters passed.
  if (__argc__ == 1) return array->Initialize(4);

  // Take the arguments as elements.
  int number_of_elements = __argc__ - 1;
  Smi* len = Smi::FromInt(number_of_elements);
  Object* obj = Heap::AllocateFixedArrayWithHoles(len->value());
  if (obj->IsFailure()) return obj;
  FixedArray* elms = FixedArray::cast(obj);
  FixedArray::WriteBarrierMode mode = elms->GetWriteBarrierMode();
  // Fill in the content
  for (int index = 0; index < number_of_elements; index++) {
    elms->set(index, BUILTIN_ARG(index+1), mode);
  }

  // Set length and elements on the array.
  array->set_elements(FixedArray::cast(obj));
  array->set_length(len);

  return array;
}
BUILTIN_END


BUILTIN(ArrayPush) {
  JSArray* array = JSArray::cast(*receiver);
  ASSERT(array->HasFastElements());

  // Make sure we have space for the elements.
  int len = Smi::cast(array->length())->value();

  // Set new length.
  int new_length = len + __argc__ - 1;
  FixedArray* elms = FixedArray::cast(array->elements());

  if (new_length <= elms->length()) {
    // Backing storage has extra space for the provided values.
    for (int index = 0; index < __argc__ - 1; index++) {
      elms->set(index + len, BUILTIN_ARG(index+1));
    }
  } else {
    // New backing storage is needed.
    int capacity = new_length + (new_length >> 1) + 16;
    Object* obj = Heap::AllocateFixedArrayWithHoles(capacity);
    if (obj->IsFailure()) return obj;
    FixedArray* new_elms = FixedArray::cast(obj);
    FixedArray::WriteBarrierMode mode = new_elms->GetWriteBarrierMode();
    // Fill out the new array with old elements.
    for (int i = 0; i < len; i++) new_elms->set(i, elms->get(i), mode);
    // Add the provided values.
    for (int index = 0; index < __argc__ - 1; index++) {
      new_elms->set(index + len, BUILTIN_ARG(index+1), mode);
    }
    // Set the new backing storage.
    array->set_elements(new_elms);
  }
  // Set the length.
  array->set_length(Smi::FromInt(new_length));
  return array->length();
}
BUILTIN_END


BUILTIN(ArrayPop) {
  JSArray* array = JSArray::cast(*receiver);
  ASSERT(array->HasFastElements());
  Object* undefined = Heap::undefined_value();

  int len = Smi::cast(array->length())->value();
  if (len == 0) return undefined;

  // Get top element
  FixedArray* elms = FixedArray::cast(array->elements());
  Object* top = elms->get(len - 1);

  // Set the length.
  array->set_length(Smi::FromInt(len - 1));

  if (!top->IsTheHole()) {
    // Delete the top element.
    elms->set_the_hole(len - 1);

    return top;
  }

  // Remember to check the prototype chain.
  JSFunction* array_function =
      Top::context()->global_context()->array_function();
  JSObject* prototype = JSObject::cast(array_function->prototype());
  top = prototype->GetElement(len - 1);

  return top;
}
BUILTIN_END


// -----------------------------------------------------------------------------
//


// Returns the holder JSObject if the function can legally be called
// with this receiver.  Returns Heap::null_value() if the call is
// illegal.  Any arguments that don't fit the expected type is
// overwritten with undefined.  Arguments that do fit the expected
// type is overwritten with the object in the prototype chain that
// actually has that type.
static inline Object* TypeCheck(int argc,
                                Object** argv,
                                FunctionTemplateInfo* info) {
  Object* recv = argv[0];
  Object* sig_obj = info->signature();
  if (sig_obj->IsUndefined()) return recv;
  SignatureInfo* sig = SignatureInfo::cast(sig_obj);
  // If necessary, check the receiver
  Object* recv_type = sig->receiver();

  Object* holder = recv;
  if (!recv_type->IsUndefined()) {
    for (; holder != Heap::null_value(); holder = holder->GetPrototype()) {
      if (holder->IsInstanceOf(FunctionTemplateInfo::cast(recv_type))) {
        break;
      }
    }
    if (holder == Heap::null_value()) return holder;
  }
  Object* args_obj = sig->args();
  // If there is no argument signature we're done
  if (args_obj->IsUndefined()) return holder;
  FixedArray* args = FixedArray::cast(args_obj);
  int length = args->length();
  if (argc <= length) length = argc - 1;
  for (int i = 0; i < length; i++) {
    Object* argtype = args->get(i);
    if (argtype->IsUndefined()) continue;
    Object** arg = &argv[-1 - i];
    Object* current = *arg;
    for (; current != Heap::null_value(); current = current->GetPrototype()) {
      if (current->IsInstanceOf(FunctionTemplateInfo::cast(argtype))) {
        *arg = current;
        break;
      }
    }
    if (current == Heap::null_value()) *arg = Heap::undefined_value();
  }
  return holder;
}


BUILTIN(HandleApiCall) {
  HandleScope scope;
  bool is_construct = CalledAsConstructor();

  // TODO(1238487): This is not nice. We need to get rid of this
  // kludgy behavior and start handling API calls in a more direct
  // way - maybe compile specialized stubs lazily?.
  Handle<JSFunction> function =
      Handle<JSFunction>(JSFunction::cast(Builtins::builtin_passed_function));

  if (is_construct) {
    Handle<FunctionTemplateInfo> desc =
        Handle<FunctionTemplateInfo>(
            FunctionTemplateInfo::cast(function->shared()->function_data()));
    bool pending_exception = false;
    Factory::ConfigureInstance(desc, Handle<JSObject>::cast(receiver),
                               &pending_exception);
    ASSERT(Top::has_pending_exception() == pending_exception);
    if (pending_exception) return Failure::Exception();
  }

  FunctionTemplateInfo* fun_data =
      FunctionTemplateInfo::cast(function->shared()->function_data());