frames.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 "frames-inl.h"
#include "scopeinfo.h"
#include "string-stream.h"
#include "top.h"
#include "zone-inl.h"

namespace v8 { namespace internal {

// Iterator that supports traversing the stack handlers of a
// particular frame. Needs to know the top of the handler chain.
class StackHandlerIterator BASE_EMBEDDED {
 public:
  StackHandlerIterator(const StackFrame* frame, StackHandler* handler)
      : limit_(frame->fp()), handler_(handler) {
    // Make sure the handler has already been unwound to this frame.
    ASSERT(frame->sp() <= handler->address());
  }

  StackHandler* handler() const { return handler_; }

  bool done() { return handler_->address() > limit_; }
  void Advance() {
    ASSERT(!done());
    handler_ = handler_->next();
  }

 private:
  const Address limit_;
  StackHandler* handler_;
};


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


#define INITIALIZE_SINGLETON(type, field) field##_(this),
StackFrameIterator::StackFrameIterator()
    : STACK_FRAME_TYPE_LIST(INITIALIZE_SINGLETON)
      frame_(NULL), handler_(NULL), thread_(Top::GetCurrentThread()) {
  Reset();
}
StackFrameIterator::StackFrameIterator(ThreadLocalTop* t)
    : STACK_FRAME_TYPE_LIST(INITIALIZE_SINGLETON)
      frame_(NULL), handler_(NULL), thread_(t) {
  Reset();
}
#undef INITIALIZE_SINGLETON


void StackFrameIterator::Advance() {
  ASSERT(!done());
  // Compute the state of the calling frame before restoring
  // callee-saved registers and unwinding handlers. This allows the
  // frame code that computes the caller state to access the top
  // handler and the value of any callee-saved register if needed.
  StackFrame::State state;
  StackFrame::Type type = frame_->GetCallerState(&state);

  // Unwind handlers corresponding to the current frame.
  StackHandlerIterator it(frame_, handler_);
  while (!it.done()) it.Advance();
  handler_ = it.handler();

  // Advance to the calling frame.
  frame_ = SingletonFor(type, &state);

  // When we're done iterating over the stack frames, the handler
  // chain must have been completely unwound.
  ASSERT(!done() || handler_ == NULL);
}


void StackFrameIterator::Reset() {
  Address fp = Top::c_entry_fp(thread_);
  StackFrame::State state;
  StackFrame::Type type = ExitFrame::GetStateForFramePointer(fp, &state);
  frame_ = SingletonFor(type, &state);
  handler_ = StackHandler::FromAddress(Top::handler(thread_));
}


StackFrame* StackFrameIterator::SingletonFor(StackFrame::Type type,
                                             StackFrame::State* state) {
#define FRAME_TYPE_CASE(type, field) \
  case StackFrame::type: result = &field##_; break;

  StackFrame* result = NULL;
  switch (type) {
    case StackFrame::NONE: return NULL;
    STACK_FRAME_TYPE_LIST(FRAME_TYPE_CASE)
    default: break;
  }
  ASSERT(result != NULL);
  result->state_ = *state;
  return result;

#undef FRAME_TYPE_CASE
}


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


JavaScriptFrameIterator::JavaScriptFrameIterator(StackFrame::Id id) {
  while (true) {
    Advance();
    if (frame()->id() == id) return;
  }
}


void JavaScriptFrameIterator::Advance() {
  do {
    iterator_.Advance();
  } while (!iterator_.done() && !iterator_.frame()->is_java_script());
}


void JavaScriptFrameIterator::AdvanceToArgumentsFrame() {
  if (!frame()->has_adapted_arguments()) return;
  iterator_.Advance();
  ASSERT(iterator_.frame()->is_arguments_adaptor());
}


void JavaScriptFrameIterator::Reset() {
  iterator_.Reset();
  Advance();
}


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


void StackHandler::Cook(Code* code) {
  ASSERT(code->contains(pc()));
  set_pc(AddressFrom<Address>(pc() - code->instruction_start()));
}


void StackHandler::Uncook(Code* code) {
  set_pc(code->instruction_start() + OffsetFrom(pc()));
  ASSERT(code->contains(pc()));
}


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


bool StackFrame::HasHandler() const {
  StackHandlerIterator it(this, top_handler());
  return !it.done();
}


void StackFrame::CookFramesForThread(ThreadLocalTop* thread) {
  ASSERT(!thread->stack_is_cooked());
  for (StackFrameIterator it(thread); !it.done(); it.Advance()) {
    it.frame()->Cook();
  }
  thread->set_stack_is_cooked(true);
}


void StackFrame::UncookFramesForThread(ThreadLocalTop* thread) {
  ASSERT(thread->stack_is_cooked());
  for (StackFrameIterator it(thread); !it.done(); it.Advance()) {
    it.frame()->Uncook();
  }
  thread->set_stack_is_cooked(false);
}


void StackFrame::Cook() {
  Code* code = FindCode();
  for (StackHandlerIterator it(this, top_handler()); !it.done(); it.Advance()) {
    it.handler()->Cook(code);
  }
  ASSERT(code->contains(pc()));
  set_pc(AddressFrom<Address>(pc() - code->instruction_start()));
}


void StackFrame::Uncook() {
  Code* code = FindCode();
  for (StackHandlerIterator it(this, top_handler()); !it.done(); it.Advance()) {
    it.handler()->Uncook(code);
  }
  set_pc(code->instruction_start() + OffsetFrom(pc()));
  ASSERT(code->contains(pc()));
}


Code* EntryFrame::FindCode() const {
  return Heap::js_entry_code();
}


StackFrame::Type EntryFrame::GetCallerState(State* state) const {
  const int offset = EntryFrameConstants::kCallerFPOffset;
  Address fp = Memory::Address_at(this->fp() + offset);
  return ExitFrame::GetStateForFramePointer(fp, state);
}


Code* EntryConstructFrame::FindCode() const {
  return Heap::js_construct_entry_code();
}


Code* ExitFrame::FindCode() const {
  return Heap::c_entry_code();
}


StackFrame::Type ExitFrame::GetCallerState(State* state) const {
  // Setup the caller state.
  state->sp = pp();
  state->fp = Memory::Address_at(fp() + ExitFrameConstants::kCallerFPOffset);
  state->pc_address
      = reinterpret_cast<Address*>(fp() + ExitFrameConstants::kCallerPCOffset);
  return ComputeType(state);
}


Address ExitFrame::GetCallerStackPointer() const {
  return fp() + ExitFrameConstants::kPPDisplacement;
}


Code* ExitDebugFrame::FindCode() const {
  return Heap::c_entry_debug_break_code();
}


Address StandardFrame::GetExpressionAddress(int n) const {
  const int offset = StandardFrameConstants::kExpressionsOffset;
  return fp() + offset - n * kPointerSize;
}


int StandardFrame::ComputeExpressionsCount() const {
  const int offset =
      StandardFrameConstants::kExpressionsOffset + kPointerSize;
  Address base = fp() + offset;
  Address limit = sp();
  ASSERT(base >= limit);  // stack grows downwards
  // Include register-allocated locals in number of expressions.
  return (base - limit) / kPointerSize;
}


StackFrame::Type StandardFrame::GetCallerState(State* state) const {
  state->sp = caller_sp();
  state->fp = caller_fp();
  state->pc_address = reinterpret_cast<Address*>(ComputePCAddress(fp()));
  return ComputeType(state);
}


bool StandardFrame::IsExpressionInsideHandler(int n) const {
  Address address = GetExpressionAddress(n);
  for (StackHandlerIterator it(this, top_handler()); !it.done(); it.Advance()) {
    if (it.handler()->includes(address)) return true;
  }