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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.
#ifndef V8_EXECUTION_H_
#define V8_EXECUTION_H_
namespace v8 {
namespace internal {
// Flag used to set the interrupt causes.
enum InterruptFlag {
INTERRUPT = 1 << 0,
DEBUGBREAK = 1 << 1,
DEBUGCOMMAND = 1 << 2,
PREEMPT = 1 << 3,
TERMINATE = 1 << 4
};
class Execution : public AllStatic {
public:
// Call a function, the caller supplies a receiver and an array
// of arguments. Arguments are Object* type. After function returns,
// pointers in 'args' might be invalid.
//
// *pending_exception tells whether the invoke resulted in
// a pending exception.
//
static Handle<Object> Call(Handle<JSFunction> func,
Handle<Object> receiver,
int argc,
Object*** args,
bool* pending_exception);
// Construct object from function, the caller supplies an array of
// arguments. Arguments are Object* type. After function returns,
// pointers in 'args' might be invalid.
//
// *pending_exception tells whether the invoke resulted in
// a pending exception.
//
static Handle<Object> New(Handle<JSFunction> func,
int argc,
Object*** args,
bool* pending_exception);
// Call a function, just like Call(), but make sure to silently catch
// any thrown exceptions. The return value is either the result of
// calling the function (if caught exception is false) or the exception
// that occurred (if caught exception is true).
static Handle<Object> TryCall(Handle<JSFunction> func,
Handle<Object> receiver,
int argc,
Object*** args,
bool* caught_exception);
// ECMA-262 9.2
static Handle<Object> ToBoolean(Handle<Object> obj);
// ECMA-262 9.3
static Handle<Object> ToNumber(Handle<Object> obj, bool* exc);
// ECMA-262 9.4
static Handle<Object> ToInteger(Handle<Object> obj, bool* exc);
// ECMA-262 9.5
static Handle<Object> ToInt32(Handle<Object> obj, bool* exc);
// ECMA-262 9.6
static Handle<Object> ToUint32(Handle<Object> obj, bool* exc);
// ECMA-262 9.8
static Handle<Object> ToString(Handle<Object> obj, bool* exc);
// ECMA-262 9.8
static Handle<Object> ToDetailString(Handle<Object> obj, bool* exc);
// ECMA-262 9.9
static Handle<Object> ToObject(Handle<Object> obj, bool* exc);
// Create a new date object from 'time'.
static Handle<Object> NewDate(double time, bool* exc);
// Create a new regular expression object from 'pattern' and 'flags'.
static Handle<JSRegExp> NewJSRegExp(Handle<String> pattern,
Handle<String> flags,
bool* exc);
// Used to implement [] notation on strings (calls JS code)
static Handle<Object> CharAt(Handle<String> str, uint32_t index);
static Handle<Object> GetFunctionFor();
static Handle<JSFunction> InstantiateFunction(
Handle<FunctionTemplateInfo> data, bool* exc);
static Handle<JSObject> InstantiateObject(Handle<ObjectTemplateInfo> data,
bool* exc);
static void ConfigureInstance(Handle<Object> instance,
Handle<Object> data,
bool* exc);
static Handle<String> GetStackTraceLine(Handle<Object> recv,
Handle<JSFunction> fun,
Handle<Object> pos,
Handle<Object> is_global);
#ifdef ENABLE_DEBUGGER_SUPPORT
static Object* DebugBreakHelper();
static void ProcessDebugMesssages(bool debug_command_only);
#endif
// If the stack guard is triggered, but it is not an actual
// stack overflow, then handle the interruption accordingly.
MUST_USE_RESULT static MaybeObject* HandleStackGuardInterrupt();
// Get a function delegate (or undefined) for the given non-function
// object. Used for support calling objects as functions.
static Handle<Object> GetFunctionDelegate(Handle<Object> object);
// Get a function delegate (or undefined) for the given non-function
// object. Used for support calling objects as constructors.
static Handle<Object> GetConstructorDelegate(Handle<Object> object);
};
class ExecutionAccess;
// StackGuard contains the handling of the limits that are used to limit the
// number of nested invocations of JavaScript and the stack size used in each
// invocation.
class StackGuard : public AllStatic {
public:
// Pass the address beyond which the stack should not grow. The stack
// is assumed to grow downwards.
static void SetStackLimit(uintptr_t limit);
// Threading support.
static char* ArchiveStackGuard(char* to);
static char* RestoreStackGuard(char* from);
static int ArchiveSpacePerThread();
static void FreeThreadResources();
// Sets up the default stack guard for this thread if it has not
// already been set up.
static void InitThread(const ExecutionAccess& lock);
// Clears the stack guard for this thread so it does not look as if
// it has been set up.
static void ClearThread(const ExecutionAccess& lock);
static bool IsStackOverflow();
static bool IsPreempted();
static void Preempt();
static bool IsInterrupted();
static void Interrupt();
static bool IsTerminateExecution();
static void TerminateExecution();
#ifdef ENABLE_DEBUGGER_SUPPORT
static bool IsDebugBreak();
static void DebugBreak();
static bool IsDebugCommand();
static void DebugCommand();
#endif
static void Continue(InterruptFlag after_what);
// This provides an asynchronous read of the stack limits for the current
// thread. There are no locks protecting this, but it is assumed that you
// have the global V8 lock if you are using multiple V8 threads.
static uintptr_t climit() {
return thread_local_.climit_;
}
static uintptr_t jslimit() {
return thread_local_.jslimit_;
}
static uintptr_t real_jslimit() {
return thread_local_.real_jslimit_;
}
static Address address_of_jslimit() {
return reinterpret_cast<Address>(&thread_local_.jslimit_);
}
static Address address_of_real_jslimit() {
return reinterpret_cast<Address>(&thread_local_.real_jslimit_);
}
private:
// You should hold the ExecutionAccess lock when calling this method.
static bool has_pending_interrupts(const ExecutionAccess& lock) {
// Sanity check: We shouldn't be asking about pending interrupts
// unless we're not postponing them anymore.
ASSERT(!should_postpone_interrupts(lock));
return thread_local_.interrupt_flags_ != 0;
}
// You should hold the ExecutionAccess lock when calling this method.
static bool should_postpone_interrupts(const ExecutionAccess& lock) {
return thread_local_.postpone_interrupts_nesting_ > 0;
}
// You should hold the ExecutionAccess lock when calling this method.
static void set_interrupt_limits(const ExecutionAccess& lock) {
// Ignore attempts to interrupt when interrupts are postponed.
if (should_postpone_interrupts(lock)) return;
thread_local_.jslimit_ = kInterruptLimit;
thread_local_.climit_ = kInterruptLimit;
Heap::SetStackLimits();
}
// Reset limits to actual values. For example after handling interrupt.
// You should hold the ExecutionAccess lock when calling this method.
static void reset_limits(const ExecutionAccess& lock) {
thread_local_.jslimit_ = thread_local_.real_jslimit_;
thread_local_.climit_ = thread_local_.real_climit_;
Heap::SetStackLimits();
}
// Enable or disable interrupts.
static void EnableInterrupts();
static void DisableInterrupts();
static const uintptr_t kLimitSize = kPointerSize * 128 * KB;
#ifdef V8_TARGET_ARCH_X64
static const uintptr_t kInterruptLimit = V8_UINT64_C(0xfffffffffffffffe);
static const uintptr_t kIllegalLimit = V8_UINT64_C(0xfffffffffffffff8);
#else
static const uintptr_t kInterruptLimit = 0xfffffffe;
static const uintptr_t kIllegalLimit = 0xfffffff8;
#endif
class ThreadLocal {
public:
ThreadLocal() { Clear(); }
// You should hold the ExecutionAccess lock when you call Initialize or
// Clear.
void Initialize();
void Clear();
// The stack limit is split into a JavaScript and a C++ stack limit. These
// two are the same except when running on a simulator where the C++ and
// JavaScript stacks are separate. Each of the two stack limits have two
// values. The one eith the real_ prefix is the actual stack limit
// set for the VM. The one without the real_ prefix has the same value as
// the actual stack limit except when there is an interruption (e.g. debug
// break or preemption) in which case it is lowered to make stack checks
// fail. Both the generated code and the runtime system check against the
// one without the real_ prefix.
uintptr_t real_jslimit_; // Actual JavaScript stack limit set for the VM.
uintptr_t jslimit_;
uintptr_t real_climit_; // Actual C++ stack limit set for the VM.
uintptr_t climit_;
int nesting_;
int postpone_interrupts_nesting_;
int interrupt_flags_;
};
static ThreadLocal thread_local_;
friend class StackLimitCheck;
friend class PostponeInterruptsScope;
};
// Support for checking for stack-overflows in C++ code.
class StackLimitCheck BASE_EMBEDDED {
public:
bool HasOverflowed() const {
// Stack has overflowed in C++ code only if stack pointer exceeds the C++
// stack guard and the limits are not set to interrupt values.
// TODO(214): Stack overflows are ignored if a interrupt is pending. This
// code should probably always use the initial C++ limit.
return (reinterpret_cast<uintptr_t>(this) < StackGuard::climit()) &&
StackGuard::IsStackOverflow();
}
};
// Support for temporarily postponing interrupts. When the outermost
// postpone scope is left the interrupts will be re-enabled and any
// interrupts that occurred while in the scope will be taken into
// account.
class PostponeInterruptsScope BASE_EMBEDDED {
public:
PostponeInterruptsScope() {
StackGuard::thread_local_.postpone_interrupts_nesting_++;
StackGuard::DisableInterrupts();
}
~PostponeInterruptsScope() {
if (--StackGuard::thread_local_.postpone_interrupts_nesting_ == 0) {
StackGuard::EnableInterrupts();
}
}
};
class GCExtension : public v8::Extension {
public:
GCExtension() : v8::Extension("v8/gc", kSource) {}
virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
v8::Handle<v8::String> name);
static v8::Handle<v8::Value> GC(const v8::Arguments& args);
private:
static const char* const kSource;
};
class ExternalizeStringExtension : public v8::Extension {
public:
ExternalizeStringExtension() : v8::Extension("v8/externalize", kSource) {}
virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
v8::Handle<v8::String> name);
static v8::Handle<v8::Value> Externalize(const v8::Arguments& args);
static v8::Handle<v8::Value> IsAscii(const v8::Arguments& args);
private:
static const char* const kSource;
};
} } // namespace v8::internal
#endif // V8_EXECUTION_H_