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// Copyright 2011 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 "bootstrapper.h"
#include "codegen.h"
#include "debug.h"
#include "runtime-profiler.h"
#include "simulator.h"
#include "v8threads.h"
#include "vm-state-inl.h"
namespace v8 {
namespace internal {
StackGuard::StackGuard()
: isolate_(NULL) {
}
void StackGuard::set_interrupt_limits(const ExecutionAccess& lock) {
ASSERT(isolate_ != NULL);
// Ignore attempts to interrupt when interrupts are postponed.
if (should_postpone_interrupts(lock)) return;
thread_local_.jslimit_ = kInterruptLimit;
thread_local_.climit_ = kInterruptLimit;
isolate_->heap()->SetStackLimits();
}
void StackGuard::reset_limits(const ExecutionAccess& lock) {
ASSERT(isolate_ != NULL);
thread_local_.jslimit_ = thread_local_.real_jslimit_;
thread_local_.climit_ = thread_local_.real_climit_;
isolate_->heap()->SetStackLimits();
}
static Handle<Object> Invoke(bool construct,
Handle<JSFunction> func,
Handle<Object> receiver,
int argc,
Object*** args,
bool* has_pending_exception) {
Isolate* isolate = func->GetIsolate();
// Entering JavaScript.
VMState state(isolate, JS);
// Placeholder for return value.
MaybeObject* 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();
}
// Convert calls on global objects to be calls on the global
// receiver instead to avoid having a 'this' pointer which refers
// directly to a global object.
if (receiver->IsGlobalObject()) {
Handle<GlobalObject> global = Handle<GlobalObject>::cast(receiver);
receiver = Handle<JSObject>(global->global_receiver());
}
// Make sure that the global object of the context we're about to
// make the current one is indeed a global object.
ASSERT(func->context()->global()->IsGlobalObject());
{
// Save and restore context around invocation and block the
// allocation of handles without explicit handle scopes.
SaveContext save(isolate);
NoHandleAllocation na;
JSEntryFunction entry = FUNCTION_CAST<JSEntryFunction>(code->entry());
// Call the function through the right JS entry stub.
byte* entry_address = func->code()->entry();
JSFunction* function = *func;
Object* receiver_pointer = *receiver;
value = CALL_GENERATED_CODE(entry, entry_address, function,
receiver_pointer, 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 == Isolate::Current()->has_pending_exception());
if (*has_pending_exception) {
isolate->ReportPendingMessages();
if (isolate->pending_exception() == Failure::OutOfMemoryException()) {
if (!isolate->ignore_out_of_memory()) {
V8::FatalProcessOutOfMemory("JS", true);
}
}
return Handle<Object>();
} else {
isolate->clear_pending_message();
}
return Handle<Object>(value->ToObjectUnchecked(), isolate);
}
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, Isolate::Current()->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());
Isolate* isolate = Isolate::Current();
ASSERT(isolate->has_pending_exception());
ASSERT(isolate->external_caught_exception());
if (isolate->pending_exception() ==
isolate->heap()->termination_exception()) {
result = isolate->factory()->termination_exception();
} else {
result = v8::Utils::OpenHandle(*catcher.Exception());
}
isolate->OptionalRescheduleException(true);
}
ASSERT(!Isolate::Current()->has_pending_exception());
ASSERT(!Isolate::Current()->external_caught_exception());
return result;
}
Handle<Object> Execution::GetFunctionDelegate(Handle<Object> object) {
ASSERT(!object->IsJSFunction());
Isolate* isolate = Isolate::Current();
Factory* factory = isolate->factory();
// If you return a function from here, it will be called when an
// attempt is made to call the given object as a function.
// Regular expressions can be called as functions in both Firefox
// and Safari so we allow it too.
if (object->IsJSRegExp()) {
Handle<String> exec = factory->exec_symbol();
// TODO(lrn): Bug 617. We should use the default function here, not the
// one on the RegExp object.
Object* exec_function;
{ MaybeObject* maybe_exec_function = object->GetProperty(*exec);
// This can lose an exception, but the alternative is to put a failure
// object in a handle, which is not GC safe.
if (!maybe_exec_function->ToObject(&exec_function)) {
return factory->undefined_value();
}
}
return Handle<Object>(exec_function);
}
// 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>(
isolate->global_context()->call_as_function_delegate());
}
return factory->undefined_value();
}
Handle<Object> Execution::GetConstructorDelegate(Handle<Object> object) {
ASSERT(!object->IsJSFunction());
Isolate* isolate = Isolate::Current();
// If you return a function from here, it will be called when an
// attempt is made to call the given object as a constructor.
// 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>(
isolate->global_context()->call_as_constructor_delegate());
}
return isolate->factory()->undefined_value();
}
bool StackGuard::IsStackOverflow() {
ExecutionAccess access(isolate_);
return (thread_local_.jslimit_ != kInterruptLimit &&
thread_local_.climit_ != kInterruptLimit);
}
void StackGuard::EnableInterrupts() {
ExecutionAccess access(isolate_);
if (has_pending_interrupts(access)) {
set_interrupt_limits(access);
}
}
void StackGuard::SetStackLimit(uintptr_t limit) {
ExecutionAccess access(isolate_);
// If the current limits are special (eg due to a pending interrupt) then
// leave them alone.
uintptr_t jslimit = SimulatorStack::JsLimitFromCLimit(limit);
if (thread_local_.jslimit_ == thread_local_.real_jslimit_) {
thread_local_.jslimit_ = jslimit;
}
if (thread_local_.climit_ == thread_local_.real_climit_) {
thread_local_.climit_ = limit;
}
thread_local_.real_climit_ = limit;
thread_local_.real_jslimit_ = jslimit;
}
void StackGuard::DisableInterrupts() {
ExecutionAccess access(isolate_);
reset_limits(access);
}
bool StackGuard::IsInterrupted() {
ExecutionAccess access(isolate_);
return thread_local_.interrupt_flags_ & INTERRUPT;
}
void StackGuard::Interrupt() {
ExecutionAccess access(isolate_);
thread_local_.interrupt_flags_ |= INTERRUPT;
set_interrupt_limits(access);
}
bool StackGuard::IsPreempted() {
ExecutionAccess access(isolate_);
return thread_local_.interrupt_flags_ & PREEMPT;
}
void StackGuard::Preempt() {
ExecutionAccess access(isolate_);
thread_local_.interrupt_flags_ |= PREEMPT;
set_interrupt_limits(access);
}
bool StackGuard::IsTerminateExecution() {
ExecutionAccess access(isolate_);
return thread_local_.interrupt_flags_ & TERMINATE;
}
void StackGuard::TerminateExecution() {
ExecutionAccess access(isolate_);
thread_local_.interrupt_flags_ |= TERMINATE;
set_interrupt_limits(access);
}
bool StackGuard::IsRuntimeProfilerTick() {
ExecutionAccess access(isolate_);
return thread_local_.interrupt_flags_ & RUNTIME_PROFILER_TICK;
}
void StackGuard::RequestRuntimeProfilerTick() {
// Ignore calls if we're not optimizing or if we can't get the lock.
if (FLAG_opt && ExecutionAccess::TryLock(isolate_)) {
thread_local_.interrupt_flags_ |= RUNTIME_PROFILER_TICK;
if (thread_local_.postpone_interrupts_nesting_ == 0) {
thread_local_.jslimit_ = thread_local_.climit_ = kInterruptLimit;
isolate_->heap()->SetStackLimits();
}
ExecutionAccess::Unlock(isolate_);
}
}
#ifdef ENABLE_DEBUGGER_SUPPORT
bool StackGuard::IsDebugBreak() {
ExecutionAccess access(isolate_);
return thread_local_.interrupt_flags_ & DEBUGBREAK;
}
void StackGuard::DebugBreak() {
ExecutionAccess access(isolate_);
thread_local_.interrupt_flags_ |= DEBUGBREAK;
set_interrupt_limits(access);
}
bool StackGuard::IsDebugCommand() {
ExecutionAccess access(isolate_);
return thread_local_.interrupt_flags_ & DEBUGCOMMAND;
}
void StackGuard::DebugCommand() {
if (FLAG_debugger_auto_break) {
ExecutionAccess access(isolate_);
thread_local_.interrupt_flags_ |= DEBUGCOMMAND;
set_interrupt_limits(access);
}
}
#endif
void StackGuard::Continue(InterruptFlag after_what) {
ExecutionAccess access(isolate_);
thread_local_.interrupt_flags_ &= ~static_cast<int>(after_what);
if (!should_postpone_interrupts(access) && !has_pending_interrupts(access)) {
reset_limits(access);
}
}
char* StackGuard::ArchiveStackGuard(char* to) {
ExecutionAccess access(isolate_);
memcpy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
ThreadLocal blank;
// Set the stack limits using the old thread_local_.
// TODO(isolates): This was the old semantics of constructing a ThreadLocal
// (as the ctor called SetStackLimits, which looked at the
// current thread_local_ from StackGuard)-- but is this
// really what was intended?
isolate_->heap()->SetStackLimits();
thread_local_ = blank;
return to + sizeof(ThreadLocal);
}
char* StackGuard::RestoreStackGuard(char* from) {
ExecutionAccess access(isolate_);
memcpy(reinterpret_cast<char*>(&thread_local_), from, sizeof(ThreadLocal));
isolate_->heap()->SetStackLimits();
return from + sizeof(ThreadLocal);
}
void StackGuard::FreeThreadResources() {
Isolate::CurrentPerIsolateThreadData()->set_stack_limit(
thread_local_.real_climit_);
}
void StackGuard::ThreadLocal::Clear() {
real_jslimit_ = kIllegalLimit;
jslimit_ = kIllegalLimit;
real_climit_ = kIllegalLimit;
climit_ = kIllegalLimit;
nesting_ = 0;
postpone_interrupts_nesting_ = 0;
interrupt_flags_ = 0;
}
bool StackGuard::ThreadLocal::Initialize() {
bool should_set_stack_limits = false;
if (real_climit_ == kIllegalLimit) {
// Takes the address of the limit variable in order to find out where
// the top of stack is right now.
const uintptr_t kLimitSize = FLAG_stack_size * KB;
uintptr_t limit = reinterpret_cast<uintptr_t>(&limit) - kLimitSize;
ASSERT(reinterpret_cast<uintptr_t>(&limit) > kLimitSize);
real_jslimit_ = SimulatorStack::JsLimitFromCLimit(limit);
jslimit_ = SimulatorStack::JsLimitFromCLimit(limit);
real_climit_ = limit;
climit_ = limit;
should_set_stack_limits = true;
}
nesting_ = 0;
postpone_interrupts_nesting_ = 0;
interrupt_flags_ = 0;
return should_set_stack_limits;
}
void StackGuard::ClearThread(const ExecutionAccess& lock) {
thread_local_.Clear();
isolate_->heap()->SetStackLimits();
}
void StackGuard::InitThread(const ExecutionAccess& lock) {
if (thread_local_.Initialize()) isolate_->heap()->SetStackLimits();
uintptr_t stored_limit =
Isolate::CurrentPerIsolateThreadData()->stack_limit();
// You should hold the ExecutionAccess lock when you call this.
if (stored_limit != 0) {
StackGuard::SetStackLimit(stored_limit);
}
}
// --- C a l l s t o n a t i v e s ---
#define RETURN_NATIVE_CALL(name, argc, argv, has_pending_exception) \
do { \
Isolate* isolate = Isolate::Current(); \
Object** args[argc] = argv; \
ASSERT(has_pending_exception != NULL); \
return Call(isolate->name##_fun(), \
isolate->js_builtins_object(), argc, args, \
has_pending_exception); \
} while (false)
Handle<Object> Execution::ToBoolean(Handle<Object> obj) {
// See the similar code in runtime.js:ToBoolean.
if (obj->IsBoolean()) return obj;
bool result = true;
if (obj->IsString()) {
result = Handle<String>::cast(obj)->length() != 0;
} else if (obj->IsNull() || obj->IsUndefined()) {
result = false;
} else if (obj->IsNumber()) {
double value = obj->Number();
result = !((value == 0) || isnan(value));
}
return Handle<Object>(HEAP->ToBoolean(result));
}
Handle<Object> Execution::ToNumber(Handle<Object> obj, bool* exc) {
RETURN_NATIVE_CALL(to_number, 1, { obj.location() }, exc);
}
Handle<Object> Execution::ToString(Handle<Object> obj, bool* exc) {
RETURN_NATIVE_CALL(to_string, 1, { obj.location() }, exc);
}
Handle<Object> Execution::ToDetailString(Handle<Object> obj, bool* exc) {
RETURN_NATIVE_CALL(to_detail_string, 1, { obj.location() }, exc);
}
Handle<Object> Execution::ToObject(Handle<Object> obj, bool* exc) {
if (obj->IsJSObject()) return obj;
RETURN_NATIVE_CALL(to_object, 1, { obj.location() }, exc);
}
Handle<Object> Execution::ToInteger(Handle<Object> obj, bool* exc) {
RETURN_NATIVE_CALL(to_integer, 1, { obj.location() }, exc);
}
Handle<Object> Execution::ToUint32(Handle<Object> obj, bool* exc) {
RETURN_NATIVE_CALL(to_uint32, 1, { obj.location() }, exc);
}
Handle<Object> Execution::ToInt32(Handle<Object> obj, bool* exc) {
RETURN_NATIVE_CALL(to_int32, 1, { obj.location() }, exc);
}
Handle<Object> Execution::NewDate(double time, bool* exc) {
Handle<Object> time_obj = FACTORY->NewNumber(time);
RETURN_NATIVE_CALL(create_date, 1, { time_obj.location() }, exc);
}
#undef RETURN_NATIVE_CALL
Handle<JSRegExp> Execution::NewJSRegExp(Handle<String> pattern,
Handle<String> flags,
bool* exc) {
Handle<JSFunction> function = Handle<JSFunction>(
pattern->GetIsolate()->global_context()->regexp_function());
Handle<Object> re_obj = RegExpImpl::CreateRegExpLiteral(
function, pattern, flags, exc);
if (*exc) return Handle<JSRegExp>();
return Handle<JSRegExp>::cast(re_obj);
}
Handle<Object> Execution::CharAt(Handle<String> string, uint32_t index) {
Isolate* isolate = string->GetIsolate();
Factory* factory = isolate->factory();
int int_index = static_cast<int>(index);
if (int_index < 0 || int_index >= string->length()) {
return factory->undefined_value();
}
Handle<Object> char_at =
GetProperty(isolate->js_builtins_object(),
factory->char_at_symbol());
if (!char_at->IsJSFunction()) {
return factory->undefined_value();
}
bool caught_exception;
Handle<Object> index_object = factory->NewNumberFromInt(int_index);
Object** index_arg[] = { index_object.location() };
Handle<Object> result = TryCall(Handle<JSFunction>::cast(char_at),
string,
ARRAY_SIZE(index_arg),
index_arg,
&caught_exception);
if (caught_exception) {
return factory->undefined_value();
}
return result;
}
Handle<JSFunction> Execution::InstantiateFunction(
Handle<FunctionTemplateInfo> data, bool* exc) {
Isolate* isolate = data->GetIsolate();
// Fast case: see if the function has already been instantiated
int serial_number = Smi::cast(data->serial_number())->value();
Object* elm =
isolate->global_context()->function_cache()->
GetElementNoExceptionThrown(serial_number);
if (elm->IsJSFunction()) return Handle<JSFunction>(JSFunction::cast(elm));
// The function has not yet been instantiated in this context; do it.
Object** args[1] = { Handle<Object>::cast(data).location() };
Handle<Object> result =
Call(isolate->instantiate_fun(),
isolate->js_builtins_object(), 1, args, exc);
if (*exc) return Handle<JSFunction>::null();
return Handle<JSFunction>::cast(result);
}
Handle<JSObject> Execution::InstantiateObject(Handle<ObjectTemplateInfo> data,
bool* exc) {
Isolate* isolate = data->GetIsolate();
if (data->property_list()->IsUndefined() &&
!data->constructor()->IsUndefined()) {
// Initialization to make gcc happy.
Object* result = NULL;
{
HandleScope scope(isolate);
Handle<FunctionTemplateInfo> cons_template =
Handle<FunctionTemplateInfo>(
FunctionTemplateInfo::cast(data->constructor()));
Handle<JSFunction> cons = InstantiateFunction(cons_template, exc);
if (*exc) return Handle<JSObject>::null();
Handle<Object> value = New(cons, 0, NULL, exc);
if (*exc) return Handle<JSObject>::null();
result = *value;
}
ASSERT(!*exc);
return Handle<JSObject>(JSObject::cast(result));
} else {
Object** args[1] = { Handle<Object>::cast(data).location() };
Handle<Object> result =
Call(isolate->instantiate_fun(),
isolate->js_builtins_object(), 1, args, exc);
if (*exc) return Handle<JSObject>::null();
return Handle<JSObject>::cast(result);
}
}
void Execution::ConfigureInstance(Handle<Object> instance,
Handle<Object> instance_template,
bool* exc) {
Isolate* isolate = Isolate::Current();
Object** args[2] = { instance.location(), instance_template.location() };
Execution::Call(isolate->configure_instance_fun(),
isolate->js_builtins_object(), 2, args, exc);
}
Handle<String> Execution::GetStackTraceLine(Handle<Object> recv,
Handle<JSFunction> fun,
Handle<Object> pos,
Handle<Object> is_global) {
Isolate* isolate = fun->GetIsolate();
const int argc = 4;
Object** args[argc] = { recv.location(),
Handle<Object>::cast(fun).location(),
pos.location(),
is_global.location() };
bool caught_exception = false;
Handle<Object> result =
TryCall(isolate->get_stack_trace_line_fun(),
isolate->js_builtins_object(), argc, args,
&caught_exception);
if (caught_exception || !result->IsString()) {
return isolate->factory()->empty_symbol();
}
return Handle<String>::cast(result);
}
static Object* RuntimePreempt() {
Isolate* isolate = Isolate::Current();
// Clear the preempt request flag.
isolate->stack_guard()->Continue(PREEMPT);
ContextSwitcher::PreemptionReceived();
#ifdef ENABLE_DEBUGGER_SUPPORT
if (isolate->debug()->InDebugger()) {
// If currently in the debugger don't do any actual preemption but record
// that preemption occoured while in the debugger.
isolate->debug()->PreemptionWhileInDebugger();
} else {
// Perform preemption.
v8::Unlocker unlocker;
Thread::YieldCPU();
}
#else
{ // NOLINT
// Perform preemption.
v8::Unlocker unlocker;
Thread::YieldCPU();
}
#endif
return isolate->heap()->undefined_value();
}
#ifdef ENABLE_DEBUGGER_SUPPORT
Object* Execution::DebugBreakHelper() {
Isolate* isolate = Isolate::Current();
// Just continue if breaks are disabled.
if (isolate->debug()->disable_break()) {
return isolate->heap()->undefined_value();
}
// Ignore debug break during bootstrapping.
if (isolate->bootstrapper()->IsActive()) {
return isolate->heap()->undefined_value();
}
{
JavaScriptFrameIterator it(isolate);
ASSERT(!it.done());
Object* fun = it.frame()->function();
if (fun && fun->IsJSFunction()) {
// Don't stop in builtin functions.
if (JSFunction::cast(fun)->IsBuiltin()) {
return isolate->heap()->undefined_value();
}
GlobalObject* global = JSFunction::cast(fun)->context()->global();
// Don't stop in debugger functions.
if (isolate->debug()->IsDebugGlobal(global)) {
return isolate->heap()->undefined_value();
}
}
}
// Collect the break state before clearing the flags.
bool debug_command_only =
isolate->stack_guard()->IsDebugCommand() &&
!isolate->stack_guard()->IsDebugBreak();
// Clear the debug break request flag.
isolate->stack_guard()->Continue(DEBUGBREAK);
ProcessDebugMesssages(debug_command_only);
// Return to continue execution.
return isolate->heap()->undefined_value();
}
void Execution::ProcessDebugMesssages(bool debug_command_only) {
Isolate* isolate = Isolate::Current();
// Clear the debug command request flag.
isolate->stack_guard()->Continue(DEBUGCOMMAND);
HandleScope scope(isolate);
// Enter the debugger. Just continue if we fail to enter the debugger.
EnterDebugger debugger;
if (debugger.FailedToEnter()) {
return;
}
// Notify the debug event listeners. Indicate auto continue if the break was
// a debug command break.
isolate->debugger()->OnDebugBreak(isolate->factory()->undefined_value(),
debug_command_only);
}
#endif
MaybeObject* Execution::HandleStackGuardInterrupt() {
Isolate* isolate = Isolate::Current();
StackGuard* stack_guard = isolate->stack_guard();
isolate->counters()->stack_interrupts()->Increment();
if (stack_guard->IsRuntimeProfilerTick()) {
isolate->counters()->runtime_profiler_ticks()->Increment();
stack_guard->Continue(RUNTIME_PROFILER_TICK);
isolate->runtime_profiler()->OptimizeNow();
}
#ifdef ENABLE_DEBUGGER_SUPPORT
if (stack_guard->IsDebugBreak() || stack_guard->IsDebugCommand()) {
DebugBreakHelper();
}
#endif
if (stack_guard->IsPreempted()) RuntimePreempt();
if (stack_guard->IsTerminateExecution()) {
stack_guard->Continue(TERMINATE);
return isolate->TerminateExecution();
}
if (stack_guard->IsInterrupted()) {
stack_guard->Continue(INTERRUPT);
return isolate->StackOverflow();
}
return isolate->heap()->undefined_value();
}
} } // namespace v8::internal