execution.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 <stdlib.h>

#include "v8.h"

#include "api.h"
#include "codegen-inl.h"

#if defined(ARM) || defined (__arm__) || defined(__thumb__)
#include "simulator-arm.h"
#else  // ia32
#include "simulator-ia32.h"
#endif

namespace v8 { namespace internal {


static Handle<Object> Invoke(bool construct,
                             Handle<JSFunction> func,
                             Handle<Object> receiver,
                             int argc,
                             Object*** args,
                             bool* has_pending_exception) {
  // Make sure we have a real function, not a boilerplate function.
  ASSERT(!func->IsBoilerplate());

  // Entering JavaScript.
  VMState state(JS);

  // Guard the stack against too much recursion.
  StackGuard guard;

  // Placeholder for return value.
  Object* value = reinterpret_cast<Object*>(kZapValue);

  typedef Object* (*JSEntryFunction)(
    byte* entry,
    Object* function,
    Object* receiver,
    int argc,
    Object*** args);

  Handle<Code> code;
  if (construct) {
    JSConstructEntryStub stub;
    code = stub.GetCode();
  } else {
    JSEntryStub stub;
    code = stub.GetCode();
  }

  {
    // Save and restore context around invocation and block the
    // allocation of handles without explicit handle scopes.
    SaveContext save;
    NoHandleAllocation na;
    JSEntryFunction entry = FUNCTION_CAST<JSEntryFunction>(code->entry());

    // Call the function through the right JS entry stub.
    value = CALL_GENERATED_CODE(entry, func->code()->entry(), *func,
                                *receiver, argc, args);
  }

#ifdef DEBUG
  value->Verify();
#endif

  // Update the pending exception flag and return the value.
  *has_pending_exception = value->IsException();
  ASSERT(*has_pending_exception == Top::has_pending_exception());

  // If the pending exception is OutOfMemoryException set out_of_memory in
  // the global context.  Note: We have to mark the global context here
  // since the GenerateThrowOutOfMemory stub cannot make a RuntimeCall to
  // set it.
  if (*has_pending_exception) {
    if (Top::pending_exception() == Failure::OutOfMemoryException()) {
      Top::context()->mark_out_of_memory();
    }
  }

  return Handle<Object>(value);
}


Handle<Object> Execution::Call(Handle<JSFunction> func,
                               Handle<Object> receiver,
                               int argc,
                               Object*** args,
                               bool* pending_exception) {
  return Invoke(false, func, receiver, argc, args, pending_exception);
}


Handle<Object> Execution::New(Handle<JSFunction> func, int argc,
                              Object*** args, bool* pending_exception) {
  return Invoke(true, func, Top::global(), argc, args, pending_exception);
}


Handle<Object> Execution::TryCall(Handle<JSFunction> func,
                                  Handle<Object> receiver,
                                  int argc,
                                  Object*** args,
                                  bool* caught_exception) {
  // Enter a try-block while executing the JavaScript code. To avoid
  // duplicate error printing it must be non-verbose.  Also, to avoid
  // creating message objects during stack overflow we shouldn't
  // capture messages.
  v8::TryCatch catcher;
  catcher.SetVerbose(false);
  catcher.SetCaptureMessage(false);

  Handle<Object> result = Invoke(false, func, receiver, argc, args,
                                 caught_exception);

  if (*caught_exception) {
    ASSERT(catcher.HasCaught());
    ASSERT(Top::has_pending_exception());
    ASSERT(Top::external_caught_exception());
    Top::optional_reschedule_exception(true);
    result = v8::Utils::OpenHandle(*catcher.Exception());
  }

  ASSERT(!Top::has_pending_exception());
  ASSERT(!Top::external_caught_exception());
  return result;
}


Handle<Object> Execution::GetFunctionDelegate(Handle<Object> object) {
  ASSERT(!object->IsJSFunction());

  // If you return a function from here, it will be called when an
  // attempt is made to call the given object as a function.

  // The regular expression code here is really meant more as an
  // example than anything else. KJS does not support calling regular
  // expressions as functions, but SpiderMonkey does.
  if (FLAG_call_regexp) {
    bool is_regexp =
        object->IsHeapObject() &&
        (HeapObject::cast(*object)->map()->constructor() ==
         *Top::regexp_function());

    if (is_regexp) {
      Handle<String> exec = Factory::exec_symbol();
      return Handle<Object>(object->GetProperty(*exec));
    }
  }

  // Objects created through the API can have an instance-call handler
  // that should be used when calling the object as a function.
  if (object->IsHeapObject() &&
      HeapObject::cast(*object)->map()->has_instance_call_handler()) {
    return Handle<JSFunction>(
        Top::global_context()->call_as_function_delegate());
  }

  return Factory::undefined_value();
}


// Static state for stack guards.
StackGuard::ThreadLocal StackGuard::thread_local_;


StackGuard::StackGuard() {
  ExecutionAccess access;
  if (thread_local_.nesting_++ == 0 &&
      thread_local_.jslimit_ != kInterruptLimit) {
    // NOTE: We assume that the stack grows towards lower addresses.
    ASSERT(thread_local_.jslimit_ == kIllegalLimit);
    ASSERT(thread_local_.climit_ == kIllegalLimit);

    thread_local_.initial_jslimit_ = thread_local_.jslimit_ =
        GENERATED_CODE_STACK_LIMIT(kLimitSize);
    // NOTE: The check for overflow is not safe as there is no guarantee that
    // the running thread has its stack in all memory up to address 0x00000000.
    thread_local_.initial_climit_ = thread_local_.climit_ =
        reinterpret_cast<uintptr_t>(this) >= kLimitSize ?
            reinterpret_cast<uintptr_t>(this) - kLimitSize : 0;

    if (thread_local_.interrupt_flags_ != 0) {
      set_limits(kInterruptLimit, access);
    }
  }
  // make sure we have proper limits setup
  ASSERT(thread_local_.jslimit_ != kIllegalLimit &&
         thread_local_.climit_ != kIllegalLimit);
}


StackGuard::~StackGuard() {
  ExecutionAccess access;
  if (--thread_local_.nesting_ == 0) {
    set_limits(kIllegalLimit, access);
  }
}


bool StackGuard::IsStackOverflow() {
  ExecutionAccess access;
  return (thread_local_.jslimit_ != kInterruptLimit &&
          thread_local_.climit_ != kInterruptLimit);
}


void StackGuard::EnableInterrupts() {
  ExecutionAccess access;
  if (IsSet(access)) {
    set_limits(kInterruptLimit, access);
  }
}


void StackGuard::SetStackLimit(uintptr_t limit) {
  ExecutionAccess access;
  // If the current limits are special (eg due to a pending interrupt) then
  // leave them alone.
  if (thread_local_.jslimit_ == thread_local_.initial_jslimit_) {
    thread_local_.jslimit_ = limit;
  }
  if (thread_local_.climit_ == thread_local_.initial_climit_) {
    thread_local_.climit_ = limit;
  }
  thread_local_.initial_climit_ = limit;
  thread_local_.initial_jslimit_ = limit;
}


void StackGuard::DisableInterrupts() {
  ExecutionAccess access;
  reset_limits(access);
}


bool StackGuard::IsSet(const ExecutionAccess& lock) {
  return thread_local_.interrupt_flags_ != 0;
}


bool StackGuard::IsInterrupted() {
  ExecutionAccess access;
  return thread_local_.interrupt_flags_ & INTERRUPT;
}


void StackGuard::Interrupt() {
  ExecutionAccess access;
  thread_local_.interrupt_flags_ |= INTERRUPT;
  set_limits(kInterruptLimit, access);
}


bool StackGuard::IsPreempted() {
  ExecutionAccess access;
  return thread_local_.interrupt_flags_ & PREEMPT;
}


void StackGuard::Preempt() {
  ExecutionAccess access;
  thread_local_.interrupt_flags_ |= PREEMPT;
  set_limits(kInterruptLimit, access);
}


bool StackGuard::IsDebugBreak() {
  ExecutionAccess access;
  return thread_local_.interrupt_flags_ & DEBUGBREAK;
}


void StackGuard::DebugBreak() {
  ExecutionAccess access;
  thread_local_.interrupt_flags_ |= DEBUGBREAK;
  set_limits(kInterruptLimit, access);
}


void StackGuard::Continue(InterruptFlag after_what) {
  ExecutionAccess access;
  thread_local_.interrupt_flags_ &= ~static_cast<int>(after_what);
  if (thread_local_.interrupt_flags_ == 0) {
    reset_limits(access);
  }
}


int StackGuard::ArchiveSpacePerThread() {
  return sizeof(ThreadLocal);
}


char* StackGuard::ArchiveStackGuard(char* to) {
  ExecutionAccess access;
  memcpy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
  ThreadLocal blank;
  thread_local_ = blank;
  return to + sizeof(ThreadLocal);
}


char* StackGuard::RestoreStackGuard(char* from) {
  ExecutionAccess access;
  memcpy(reinterpret_cast<char*>(&thread_local_), from, sizeof(ThreadLocal));
  return from + sizeof(ThreadLocal);
}