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// 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 "debug.h"
#include "execution.h"
#include "messages.h"
#include "platform.h"
#include "simulator.h"
#include "string-stream.h"
namespace v8 {
namespace internal {
ThreadLocalTop Top::thread_local_;
Mutex* Top::break_access_ = OS::CreateMutex();
NoAllocationStringAllocator* preallocated_message_space = NULL;
bool capture_stack_trace_for_uncaught_exceptions = false;
int stack_trace_for_uncaught_exceptions_frame_limit = 0;
StackTrace::StackTraceOptions stack_trace_for_uncaught_exceptions_options =
StackTrace::kOverview;
Address top_addresses[] = {
#define C(name) reinterpret_cast<Address>(Top::name()),
TOP_ADDRESS_LIST(C)
TOP_ADDRESS_LIST_PROF(C)
#undef C
NULL
};
v8::TryCatch* ThreadLocalTop::TryCatchHandler() {
return TRY_CATCH_FROM_ADDRESS(try_catch_handler_address());
}
void ThreadLocalTop::Initialize() {
c_entry_fp_ = 0;
handler_ = 0;
#ifdef ENABLE_LOGGING_AND_PROFILING
js_entry_sp_ = 0;
#endif
try_catch_handler_address_ = NULL;
context_ = NULL;
int id = ThreadManager::CurrentId();
thread_id_ = (id == 0) ? ThreadManager::kInvalidId : id;
external_caught_exception_ = false;
failed_access_check_callback_ = NULL;
save_context_ = NULL;
catcher_ = NULL;
}
Address Top::get_address_from_id(Top::AddressId id) {
return top_addresses[id];
}
char* Top::Iterate(ObjectVisitor* v, char* thread_storage) {
ThreadLocalTop* thread = reinterpret_cast<ThreadLocalTop*>(thread_storage);
Iterate(v, thread);
return thread_storage + sizeof(ThreadLocalTop);
}
void Top::IterateThread(ThreadVisitor* v) {
v->VisitThread(&thread_local_);
}
void Top::IterateThread(ThreadVisitor* v, char* t) {
ThreadLocalTop* thread = reinterpret_cast<ThreadLocalTop*>(t);
v->VisitThread(thread);
}
void Top::Iterate(ObjectVisitor* v, ThreadLocalTop* thread) {
v->VisitPointer(&(thread->pending_exception_));
v->VisitPointer(&(thread->pending_message_obj_));
v->VisitPointer(BitCast<Object**>(&(thread->pending_message_script_)));
v->VisitPointer(BitCast<Object**>(&(thread->context_)));
v->VisitPointer(&(thread->scheduled_exception_));
for (v8::TryCatch* block = thread->TryCatchHandler();
block != NULL;
block = TRY_CATCH_FROM_ADDRESS(block->next_)) {
v->VisitPointer(BitCast<Object**>(&(block->exception_)));
v->VisitPointer(BitCast<Object**>(&(block->message_)));
}
// Iterate over pointers on native execution stack.
for (StackFrameIterator it(thread); !it.done(); it.Advance()) {
it.frame()->Iterate(v);
}
}
void Top::Iterate(ObjectVisitor* v) {
ThreadLocalTop* current_t = &thread_local_;
Iterate(v, current_t);
}
void Top::InitializeThreadLocal() {
thread_local_.Initialize();
clear_pending_exception();
clear_pending_message();
clear_scheduled_exception();
}
// Create a dummy thread that will wait forever on a semaphore. The only
// purpose for this thread is to have some stack area to save essential data
// into for use by a stacks only core dump (aka minidump).
class PreallocatedMemoryThread: public Thread {
public:
PreallocatedMemoryThread() : keep_running_(true) {
wait_for_ever_semaphore_ = OS::CreateSemaphore(0);
data_ready_semaphore_ = OS::CreateSemaphore(0);
}
// When the thread starts running it will allocate a fixed number of bytes
// on the stack and publish the location of this memory for others to use.
void Run() {
EmbeddedVector<char, 15 * 1024> local_buffer;
// Initialize the buffer with a known good value.
OS::StrNCpy(local_buffer, "Trace data was not generated.\n",
local_buffer.length());
// Publish the local buffer and signal its availability.
data_ = local_buffer.start();
length_ = local_buffer.length();
data_ready_semaphore_->Signal();
while (keep_running_) {
// This thread will wait here until the end of time.
wait_for_ever_semaphore_->Wait();
}
// Make sure we access the buffer after the wait to remove all possibility
// of it being optimized away.
OS::StrNCpy(local_buffer, "PreallocatedMemoryThread shutting down.\n",
local_buffer.length());
}
static char* data() {
if (data_ready_semaphore_ != NULL) {
// Initial access is guarded until the data has been published.
data_ready_semaphore_->Wait();
delete data_ready_semaphore_;
data_ready_semaphore_ = NULL;
}
return data_;
}
static unsigned length() {
if (data_ready_semaphore_ != NULL) {
// Initial access is guarded until the data has been published.
data_ready_semaphore_->Wait();
delete data_ready_semaphore_;
data_ready_semaphore_ = NULL;
}
return length_;
}
static void StartThread() {
if (the_thread_ != NULL) return;
the_thread_ = new PreallocatedMemoryThread();
the_thread_->Start();
}
// Stop the PreallocatedMemoryThread and release its resources.
static void StopThread() {
if (the_thread_ == NULL) return;
the_thread_->keep_running_ = false;
wait_for_ever_semaphore_->Signal();
// Wait for the thread to terminate.
the_thread_->Join();
if (data_ready_semaphore_ != NULL) {
delete data_ready_semaphore_;
data_ready_semaphore_ = NULL;
}
delete wait_for_ever_semaphore_;
wait_for_ever_semaphore_ = NULL;
// Done with the thread entirely.
delete the_thread_;
the_thread_ = NULL;
}
private:
// Used to make sure that the thread keeps looping even for spurious wakeups.
bool keep_running_;
// The preallocated memory thread singleton.
static PreallocatedMemoryThread* the_thread_;
// This semaphore is used by the PreallocatedMemoryThread to wait for ever.
static Semaphore* wait_for_ever_semaphore_;
// Semaphore to signal that the data has been initialized.
static Semaphore* data_ready_semaphore_;
// Location and size of the preallocated memory block.
static char* data_;
static unsigned length_;
DISALLOW_COPY_AND_ASSIGN(PreallocatedMemoryThread);
};
PreallocatedMemoryThread* PreallocatedMemoryThread::the_thread_ = NULL;
Semaphore* PreallocatedMemoryThread::wait_for_ever_semaphore_ = NULL;
Semaphore* PreallocatedMemoryThread::data_ready_semaphore_ = NULL;
char* PreallocatedMemoryThread::data_ = NULL;
unsigned PreallocatedMemoryThread::length_ = 0;
static bool initialized = false;
void Top::Initialize() {
CHECK(!initialized);
InitializeThreadLocal();
// Only preallocate on the first initialization.
if (FLAG_preallocate_message_memory && (preallocated_message_space == NULL)) {
// Start the thread which will set aside some memory.
PreallocatedMemoryThread::StartThread();
preallocated_message_space =
new NoAllocationStringAllocator(PreallocatedMemoryThread::data(),
PreallocatedMemoryThread::length());
PreallocatedStorage::Init(PreallocatedMemoryThread::length() / 4);
}
initialized = true;
}
void Top::TearDown() {
if (initialized) {
// Remove the external reference to the preallocated stack memory.
if (preallocated_message_space != NULL) {
delete preallocated_message_space;
preallocated_message_space = NULL;
}
PreallocatedMemoryThread::StopThread();
initialized = false;
}
}
void Top::RegisterTryCatchHandler(v8::TryCatch* that) {
// The ARM simulator has a separate JS stack. We therefore register
// the C++ try catch handler with the simulator and get back an
// address that can be used for comparisons with addresses into the
// JS stack. When running without the simulator, the address
// returned will be the address of the C++ try catch handler itself.
Address address = reinterpret_cast<Address>(
SimulatorStack::RegisterCTryCatch(reinterpret_cast<uintptr_t>(that)));
thread_local_.set_try_catch_handler_address(address);
}
void Top::UnregisterTryCatchHandler(v8::TryCatch* that) {
ASSERT(thread_local_.TryCatchHandler() == that);
thread_local_.set_try_catch_handler_address(
reinterpret_cast<Address>(that->next_));
thread_local_.catcher_ = NULL;
SimulatorStack::UnregisterCTryCatch();
}
static int stack_trace_nesting_level = 0;
static StringStream* incomplete_message = NULL;
Handle<String> Top::StackTraceString() {
if (stack_trace_nesting_level == 0) {
stack_trace_nesting_level++;
HeapStringAllocator allocator;
StringStream::ClearMentionedObjectCache();
StringStream accumulator(&allocator);
incomplete_message = &accumulator;
PrintStack(&accumulator);
Handle<String> stack_trace = accumulator.ToString();
incomplete_message = NULL;
stack_trace_nesting_level = 0;
return stack_trace;
} else if (stack_trace_nesting_level == 1) {
stack_trace_nesting_level++;
OS::PrintError(
"\n\nAttempt to print stack while printing stack (double fault)\n");
OS::PrintError(
"If you are lucky you may find a partial stack dump on stdout.\n\n");
incomplete_message->OutputToStdOut();
return Factory::empty_symbol();
} else {
OS::Abort();
// Unreachable
return Factory::empty_symbol();
}
}
Handle<JSArray> Top::CaptureCurrentStackTrace(
int frame_limit, StackTrace::StackTraceOptions options) {
// Ensure no negative values.
int limit = Max(frame_limit, 0);
Handle<JSArray> stack_trace = Factory::NewJSArray(frame_limit);
Handle<String> column_key = Factory::LookupAsciiSymbol("column");
Handle<String> line_key = Factory::LookupAsciiSymbol("lineNumber");
Handle<String> script_key = Factory::LookupAsciiSymbol("scriptName");
Handle<String> function_key = Factory::LookupAsciiSymbol("functionName");
Handle<String> eval_key = Factory::LookupAsciiSymbol("isEval");
Handle<String> constructor_key = Factory::LookupAsciiSymbol("isConstructor");
StackTraceFrameIterator it;
int frames_seen = 0;
while (!it.done() && (frames_seen < limit)) {
// Create a JSObject to hold the information for the StackFrame.
Handle<JSObject> stackFrame = Factory::NewJSObject(object_function());
JavaScriptFrame* frame = it.frame();
JSFunction* fun(JSFunction::cast(frame->function()));
Script* script = Script::cast(fun->shared()->script());
if (options & StackTrace::kLineNumber) {
int script_line_offset = script->line_offset()->value();
int position = frame->code()->SourcePosition(frame->pc());
int line_number = GetScriptLineNumber(Handle<Script>(script), position);
// line_number is already shifted by the script_line_offset.
int relative_line_number = line_number - script_line_offset;
if (options & StackTrace::kColumnOffset && relative_line_number >= 0) {
Handle<FixedArray> line_ends(FixedArray::cast(script->line_ends()));
int start = (relative_line_number == 0) ? 0 :
Smi::cast(line_ends->get(relative_line_number - 1))->value() + 1;
int column_offset = position - start;
if (relative_line_number == 0) {
// For the case where the code is on the same line as the script tag.
column_offset += script->column_offset()->value();
}
SetProperty(stackFrame, column_key,
Handle<Smi>(Smi::FromInt(column_offset + 1)), NONE);
}
SetProperty(stackFrame, line_key,
Handle<Smi>(Smi::FromInt(line_number + 1)), NONE);
}
if (options & StackTrace::kScriptName) {
Handle<Object> script_name(script->name());
SetProperty(stackFrame, script_key, script_name, NONE);
}
if (options & StackTrace::kFunctionName) {
Handle<Object> fun_name(fun->shared()->name());
if (fun_name->ToBoolean()->IsFalse()) {
fun_name = Handle<Object>(fun->shared()->inferred_name());
}
SetProperty(stackFrame, function_key, fun_name, NONE);
}
if (options & StackTrace::kIsEval) {
int type = Smi::cast(script->compilation_type())->value();
Handle<Object> is_eval = (type == Script::COMPILATION_TYPE_EVAL) ?
Factory::true_value() : Factory::false_value();
SetProperty(stackFrame, eval_key, is_eval, NONE);
}
if (options & StackTrace::kIsConstructor) {
Handle<Object> is_constructor = (frame->IsConstructor()) ?
Factory::true_value() : Factory::false_value();
SetProperty(stackFrame, constructor_key, is_constructor, NONE);
}
FixedArray::cast(stack_trace->elements())->set(frames_seen, *stackFrame);
frames_seen++;
it.Advance();
}
stack_trace->set_length(Smi::FromInt(frames_seen));
return stack_trace;
}
void Top::PrintStack() {
if (stack_trace_nesting_level == 0) {
stack_trace_nesting_level++;
StringAllocator* allocator;
if (preallocated_message_space == NULL) {
allocator = new HeapStringAllocator();
} else {
allocator = preallocated_message_space;
}
NativeAllocationChecker allocation_checker(
!FLAG_preallocate_message_memory ?
NativeAllocationChecker::ALLOW :
NativeAllocationChecker::DISALLOW);
StringStream::ClearMentionedObjectCache();
StringStream accumulator(allocator);
incomplete_message = &accumulator;
PrintStack(&accumulator);
accumulator.OutputToStdOut();
accumulator.Log();
incomplete_message = NULL;
stack_trace_nesting_level = 0;
if (preallocated_message_space == NULL) {
// Remove the HeapStringAllocator created above.
delete allocator;
}
} else if (stack_trace_nesting_level == 1) {
stack_trace_nesting_level++;
OS::PrintError(
"\n\nAttempt to print stack while printing stack (double fault)\n");
OS::PrintError(
"If you are lucky you may find a partial stack dump on stdout.\n\n");
incomplete_message->OutputToStdOut();
}
}
static void PrintFrames(StringStream* accumulator,
StackFrame::PrintMode mode) {
StackFrameIterator it;
for (int i = 0; !it.done(); it.Advance()) {
it.frame()->Print(accumulator, mode, i++);
}
}
void Top::PrintStack(StringStream* accumulator) {
// The MentionedObjectCache is not GC-proof at the moment.
AssertNoAllocation nogc;
ASSERT(StringStream::IsMentionedObjectCacheClear());
// Avoid printing anything if there are no frames.
if (c_entry_fp(GetCurrentThread()) == 0) return;
accumulator->Add(
"\n==== Stack trace ============================================\n\n");
PrintFrames(accumulator, StackFrame::OVERVIEW);
accumulator->Add(
"\n==== Details ================================================\n\n");
PrintFrames(accumulator, StackFrame::DETAILS);
accumulator->PrintMentionedObjectCache();
accumulator->Add("=====================\n\n");
}
void Top::SetFailedAccessCheckCallback(v8::FailedAccessCheckCallback callback) {
thread_local_.failed_access_check_callback_ = callback;
}
void Top::ReportFailedAccessCheck(JSObject* receiver, v8::AccessType type) {
if (!thread_local_.failed_access_check_callback_) return;
ASSERT(receiver->IsAccessCheckNeeded());
ASSERT(Top::context());
// Get the data object from access check info.
JSFunction* constructor = JSFunction::cast(receiver->map()->constructor());
if (!constructor->shared()->IsApiFunction()) return;
Object* data_obj =
constructor->shared()->get_api_func_data()->access_check_info();
if (data_obj == Heap::undefined_value()) return;
HandleScope scope;
Handle<JSObject> receiver_handle(receiver);
Handle<Object> data(AccessCheckInfo::cast(data_obj)->data());
thread_local_.failed_access_check_callback_(
v8::Utils::ToLocal(receiver_handle),
type,
v8::Utils::ToLocal(data));
}
enum MayAccessDecision {
YES, NO, UNKNOWN
};
static MayAccessDecision MayAccessPreCheck(JSObject* receiver,
v8::AccessType type) {
// During bootstrapping, callback functions are not enabled yet.
if (Bootstrapper::IsActive()) return YES;
if (receiver->IsJSGlobalProxy()) {
Object* receiver_context = JSGlobalProxy::cast(receiver)->context();
if (!receiver_context->IsContext()) return NO;
// Get the global context of current top context.
// avoid using Top::global_context() because it uses Handle.
Context* global_context = Top::context()->global()->global_context();
if (receiver_context == global_context) return YES;
if (Context::cast(receiver_context)->security_token() ==
global_context->security_token())
return YES;
}
return UNKNOWN;
}
bool Top::MayNamedAccess(JSObject* receiver, Object* key, v8::AccessType type) {
ASSERT(receiver->IsAccessCheckNeeded());
// The callers of this method are not expecting a GC.
AssertNoAllocation no_gc;
// Skip checks for hidden properties access. Note, we do not
// require existence of a context in this case.
if (key == Heap::hidden_symbol()) return true;
// Check for compatibility between the security tokens in the
// current lexical context and the accessed object.
ASSERT(Top::context());
MayAccessDecision decision = MayAccessPreCheck(receiver, type);
if (decision != UNKNOWN) return decision == YES;
// Get named access check callback
JSFunction* constructor = JSFunction::cast(receiver->map()->constructor());
if (!constructor->shared()->IsApiFunction()) return false;
Object* data_obj =
constructor->shared()->get_api_func_data()->access_check_info();
if (data_obj == Heap::undefined_value()) return false;
Object* fun_obj = AccessCheckInfo::cast(data_obj)->named_callback();
v8::NamedSecurityCallback callback =
v8::ToCData<v8::NamedSecurityCallback>(fun_obj);
if (!callback) return false;
HandleScope scope;
Handle<JSObject> receiver_handle(receiver);
Handle<Object> key_handle(key);
Handle<Object> data(AccessCheckInfo::cast(data_obj)->data());
LOG(ApiNamedSecurityCheck(key));
bool result = false;
{
// Leaving JavaScript.
VMState state(EXTERNAL);
result = callback(v8::Utils::ToLocal(receiver_handle),
v8::Utils::ToLocal(key_handle),
type,
v8::Utils::ToLocal(data));
}
return result;
}
bool Top::MayIndexedAccess(JSObject* receiver,
uint32_t index,
v8::AccessType type) {
ASSERT(receiver->IsAccessCheckNeeded());
// Check for compatibility between the security tokens in the
// current lexical context and the accessed object.
ASSERT(Top::context());
// The callers of this method are not expecting a GC.
AssertNoAllocation no_gc;
MayAccessDecision decision = MayAccessPreCheck(receiver, type);
if (decision != UNKNOWN) return decision == YES;
// Get indexed access check callback
JSFunction* constructor = JSFunction::cast(receiver->map()->constructor());
if (!constructor->shared()->IsApiFunction()) return false;
Object* data_obj =
constructor->shared()->get_api_func_data()->access_check_info();
if (data_obj == Heap::undefined_value()) return false;
Object* fun_obj = AccessCheckInfo::cast(data_obj)->indexed_callback();
v8::IndexedSecurityCallback callback =
v8::ToCData<v8::IndexedSecurityCallback>(fun_obj);
if (!callback) return false;
HandleScope scope;
Handle<JSObject> receiver_handle(receiver);
Handle<Object> data(AccessCheckInfo::cast(data_obj)->data());
LOG(ApiIndexedSecurityCheck(index));
bool result = false;
{
// Leaving JavaScript.
VMState state(EXTERNAL);
result = callback(v8::Utils::ToLocal(receiver_handle),
index,
type,
v8::Utils::ToLocal(data));
}
return result;
}
const char* Top::kStackOverflowMessage =
"Uncaught RangeError: Maximum call stack size exceeded";
Failure* Top::StackOverflow() {
HandleScope scope;
Handle<String> key = Factory::stack_overflow_symbol();
Handle<JSObject> boilerplate =
Handle<JSObject>::cast(GetProperty(Top::builtins(), key));
Handle<Object> exception = Copy(boilerplate);
// TODO(1240995): To avoid having to call JavaScript code to compute
// the message for stack overflow exceptions which is very likely to
// double fault with another stack overflow exception, we use a
// precomputed message.
DoThrow(*exception, NULL, kStackOverflowMessage);
return Failure::Exception();
}
Failure* Top::TerminateExecution() {
DoThrow(Heap::termination_exception(), NULL, NULL);
return Failure::Exception();
}
Failure* Top::Throw(Object* exception, MessageLocation* location) {
DoThrow(exception, location, NULL);
return Failure::Exception();
}
Failure* Top::ReThrow(Object* exception, MessageLocation* location) {
// Set the exception being re-thrown.
set_pending_exception(exception);
return Failure::Exception();
}
Failure* Top::ThrowIllegalOperation() {
return Throw(Heap::illegal_access_symbol());
}
void Top::ScheduleThrow(Object* exception) {
// When scheduling a throw we first throw the exception to get the
// error reporting if it is uncaught before rescheduling it.
Throw(exception);
thread_local_.scheduled_exception_ = pending_exception();
thread_local_.external_caught_exception_ = false;
clear_pending_exception();
}
Object* Top::PromoteScheduledException() {
Object* thrown = scheduled_exception();
clear_scheduled_exception();
// Re-throw the exception to avoid getting repeated error reporting.
return ReThrow(thrown);
}
void Top::PrintCurrentStackTrace(FILE* out) {
StackTraceFrameIterator it;
while (!it.done()) {
HandleScope scope;
// Find code position if recorded in relocation info.
JavaScriptFrame* frame = it.frame();
int pos = frame->code()->SourcePosition(frame->pc());
Handle<Object> pos_obj(Smi::FromInt(pos));
// Fetch function and receiver.
Handle<JSFunction> fun(JSFunction::cast(frame->function()));
Handle<Object> recv(frame->receiver());
// Advance to the next JavaScript frame and determine if the
// current frame is the top-level frame.
it.Advance();
Handle<Object> is_top_level = it.done()
? Factory::true_value()
: Factory::false_value();
// Generate and print stack trace line.
Handle<String> line =
Execution::GetStackTraceLine(recv, fun, pos_obj, is_top_level);
if (line->length() > 0) {
line->PrintOn(out);
fprintf(out, "\n");
}
}
}
void Top::ComputeLocation(MessageLocation* target) {
*target = MessageLocation(Handle<Script>(Heap::empty_script()), -1, -1);
StackTraceFrameIterator it;
if (!it.done()) {
JavaScriptFrame* frame = it.frame();
JSFunction* fun = JSFunction::cast(frame->function());
Object* script = fun->shared()->script();
if (script->IsScript() &&
!(Script::cast(script)->source()->IsUndefined())) {
int pos = frame->code()->SourcePosition(frame->pc());
// Compute the location from the function and the reloc info.
Handle<Script> casted_script(Script::cast(script));
*target = MessageLocation(casted_script, pos, pos + 1);
}
}
}
bool Top::ShouldReturnException(bool* is_caught_externally,
bool catchable_by_javascript) {
// Find the top-most try-catch handler.
StackHandler* handler =
StackHandler::FromAddress(Top::handler(Top::GetCurrentThread()));
while (handler != NULL && !handler->is_try_catch()) {
handler = handler->next();
}
// Get the address of the external handler so we can compare the address to
// determine which one is closer to the top of the stack.
Address external_handler_address = thread_local_.try_catch_handler_address();
// The exception has been externally caught if and only if there is
// an external handler which is on top of the top-most try-catch
// handler.
*is_caught_externally = external_handler_address != NULL &&
(handler == NULL || handler->address() > external_handler_address ||
!catchable_by_javascript);
if (*is_caught_externally) {
// Only report the exception if the external handler is verbose.
return thread_local_.TryCatchHandler()->is_verbose_;
} else {
// Report the exception if it isn't caught by JavaScript code.
return handler == NULL;
}
}
void Top::DoThrow(Object* exception,
MessageLocation* location,
const char* message) {
ASSERT(!has_pending_exception());
HandleScope scope;
Handle<Object> exception_handle(exception);
// Determine reporting and whether the exception is caught externally.
bool is_caught_externally = false;
bool is_out_of_memory = exception == Failure::OutOfMemoryException();
bool is_termination_exception = exception == Heap::termination_exception();
bool catchable_by_javascript = !is_termination_exception && !is_out_of_memory;
bool should_return_exception =
ShouldReturnException(&is_caught_externally, catchable_by_javascript);
bool report_exception = catchable_by_javascript && should_return_exception;
#ifdef ENABLE_DEBUGGER_SUPPORT
// Notify debugger of exception.
if (catchable_by_javascript) {
Debugger::OnException(exception_handle, report_exception);
}
#endif
// Generate the message.
Handle<Object> message_obj;
MessageLocation potential_computed_location;
bool try_catch_needs_message =
is_caught_externally &&
thread_local_.TryCatchHandler()->capture_message_;
if (report_exception || try_catch_needs_message) {
if (location == NULL) {
// If no location was specified we use a computed one instead
ComputeLocation(&potential_computed_location);
location = &potential_computed_location;
}
if (!Bootstrapper::IsActive()) {
// It's not safe to try to make message objects or collect stack
// traces while the bootstrapper is active since the infrastructure
// may not have been properly initialized.
Handle<String> stack_trace;
if (FLAG_trace_exception) stack_trace = StackTraceString();
Handle<JSArray> stack_trace_object;
if (report_exception && capture_stack_trace_for_uncaught_exceptions) {
stack_trace_object = Top::CaptureCurrentStackTrace(
stack_trace_for_uncaught_exceptions_frame_limit,
stack_trace_for_uncaught_exceptions_options);
}
message_obj = MessageHandler::MakeMessageObject("uncaught_exception",
location, HandleVector<Object>(&exception_handle, 1), stack_trace,
stack_trace_object);
}
}
// Save the message for reporting if the the exception remains uncaught.
thread_local_.has_pending_message_ = report_exception;
thread_local_.pending_message_ = message;
if (!message_obj.is_null()) {
thread_local_.pending_message_obj_ = *message_obj;
if (location != NULL) {
thread_local_.pending_message_script_ = *location->script();
thread_local_.pending_message_start_pos_ = location->start_pos();
thread_local_.pending_message_end_pos_ = location->end_pos();
}
}
if (is_caught_externally) {
thread_local_.catcher_ = thread_local_.TryCatchHandler();
}
// NOTE: Notifying the debugger or generating the message
// may have caused new exceptions. For now, we just ignore
// that and set the pending exception to the original one.
set_pending_exception(*exception_handle);
}
void Top::ReportPendingMessages() {
ASSERT(has_pending_exception());
setup_external_caught();
// 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.
bool external_caught = thread_local_.external_caught_exception_;
HandleScope scope;
if (thread_local_.pending_exception_ == Failure::OutOfMemoryException()) {
context()->mark_out_of_memory();
} else if (thread_local_.pending_exception_ ==
Heap::termination_exception()) {
if (external_caught) {
thread_local_.TryCatchHandler()->can_continue_ = false;
thread_local_.TryCatchHandler()->exception_ = Heap::null_value();
}
} else {
Handle<Object> exception(pending_exception());
thread_local_.external_caught_exception_ = false;
if (external_caught) {
thread_local_.TryCatchHandler()->can_continue_ = true;
thread_local_.TryCatchHandler()->exception_ =
thread_local_.pending_exception_;
if (!thread_local_.pending_message_obj_->IsTheHole()) {
try_catch_handler()->message_ = thread_local_.pending_message_obj_;
}
}
if (thread_local_.has_pending_message_) {
thread_local_.has_pending_message_ = false;
if (thread_local_.pending_message_ != NULL) {
MessageHandler::ReportMessage(thread_local_.pending_message_);
} else if (!thread_local_.pending_message_obj_->IsTheHole()) {
Handle<Object> message_obj(thread_local_.pending_message_obj_);
if (thread_local_.pending_message_script_ != NULL) {
Handle<Script> script(thread_local_.pending_message_script_);
int start_pos = thread_local_.pending_message_start_pos_;
int end_pos = thread_local_.pending_message_end_pos_;
MessageLocation location(script, start_pos, end_pos);
MessageHandler::ReportMessage(&location, message_obj);
} else {
MessageHandler::ReportMessage(NULL, message_obj);
}
}
}
thread_local_.external_caught_exception_ = external_caught;
set_pending_exception(*exception);
}
clear_pending_message();
}
void Top::TraceException(bool flag) {
FLAG_trace_exception = flag;
}
bool Top::OptionalRescheduleException(bool is_bottom_call) {
// Allways reschedule out of memory exceptions.
if (!is_out_of_memory()) {
bool is_termination_exception =
pending_exception() == Heap::termination_exception();
// Do not reschedule the exception if this is the bottom call.
bool clear_exception = is_bottom_call;
if (is_termination_exception) {
if (is_bottom_call) {
thread_local_.external_caught_exception_ = false;
clear_pending_exception();
return false;
}
} else if (thread_local_.external_caught_exception_) {
// If the exception is externally caught, clear it if there are no
// JavaScript frames on the way to the C++ frame that has the
// external handler.
ASSERT(thread_local_.try_catch_handler_address() != NULL);
Address external_handler_address =
thread_local_.try_catch_handler_address();
JavaScriptFrameIterator it;
if (it.done() || (it.frame()->sp() > external_handler_address)) {
clear_exception = true;
}
}
// Clear the exception if needed.
if (clear_exception) {
thread_local_.external_caught_exception_ = false;
clear_pending_exception();
return false;
}
}
// Reschedule the exception.
thread_local_.scheduled_exception_ = pending_exception();
clear_pending_exception();
return true;
}
void Top::SetCaptureStackTraceForUncaughtExceptions(
bool capture,
int frame_limit,
StackTrace::StackTraceOptions options) {
capture_stack_trace_for_uncaught_exceptions = capture;
stack_trace_for_uncaught_exceptions_frame_limit = frame_limit;
stack_trace_for_uncaught_exceptions_options = options;
}
bool Top::is_out_of_memory() {
if (has_pending_exception()) {
Object* e = pending_exception();
if (e->IsFailure() && Failure::cast(e)->IsOutOfMemoryException()) {
return true;
}
}
if (has_scheduled_exception()) {
Object* e = scheduled_exception();
if (e->IsFailure() && Failure::cast(e)->IsOutOfMemoryException()) {
return true;
}
}
return false;
}
Handle<Context> Top::global_context() {
GlobalObject* global = thread_local_.context_->global();
return Handle<Context>(global->global_context());
}
Handle<Context> Top::GetCallingGlobalContext() {
JavaScriptFrameIterator it;
#ifdef ENABLE_DEBUGGER_SUPPORT
if (Debug::InDebugger()) {
while (!it.done()) {
JavaScriptFrame* frame = it.frame();
Context* context = Context::cast(frame->context());
if (context->global_context() == *Debug::debug_context()) {
it.Advance();
} else {
break;
}
}
}
#endif // ENABLE_DEBUGGER_SUPPORT
if (it.done()) return Handle<Context>::null();
JavaScriptFrame* frame = it.frame();
Context* context = Context::cast(frame->context());
return Handle<Context>(context->global_context());
}
char* Top::ArchiveThread(char* to) {
memcpy(to, reinterpret_cast<char*>(&thread_local_), sizeof(thread_local_));
InitializeThreadLocal();
return to + sizeof(thread_local_);
}
char* Top::RestoreThread(char* from) {
memcpy(reinterpret_cast<char*>(&thread_local_), from, sizeof(thread_local_));
return from + sizeof(thread_local_);
}
ExecutionAccess::ExecutionAccess() {
Top::break_access_->Lock();
}
ExecutionAccess::~ExecutionAccess() {
Top::break_access_->Unlock();
}
} } // namespace v8::internal