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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef VM_NATIVE_ARGUMENTS_H_
#define VM_NATIVE_ARGUMENTS_H_
#include "platform/assert.h"
#include "platform/memory_sanitizer.h"
#include "vm/globals.h"
#include "vm/handles_impl.h"
#include "vm/simulator.h"
#include "vm/stub_code.h"
namespace dart {
DECLARE_FLAG(bool, deoptimize_alot);
DECLARE_FLAG(bool, trace_natives);
DECLARE_FLAG(bool, verify_on_transition);
// Forward declarations.
class BootstrapNatives;
class Object;
class RawObject;
class Simulator;
class Thread;
#if defined(TESTING) || defined(DEBUG)
#if defined(USING_SIMULATOR)
#define CHECK_STACK_ALIGNMENT { \
uword current_sp = Simulator::Current()->get_register(SPREG); \
ASSERT(Utils::IsAligned(current_sp, OS::ActivationFrameAlignment())); \
}
#elif defined(TARGET_OS_WINDOWS)
// The compiler may dynamically align the stack on Windows, so do not check.
#define CHECK_STACK_ALIGNMENT { }
#else
#define CHECK_STACK_ALIGNMENT { \
uword (*func)() = reinterpret_cast<uword (*)()>( \
StubCode::GetStackPointer_entry()->EntryPoint()); \
uword current_sp = func(); \
ASSERT(Utils::IsAligned(current_sp, OS::ActivationFrameAlignment())); \
}
#endif
#define VERIFY_ON_TRANSITION \
if (FLAG_verify_on_transition) { \
VerifyPointersVisitor::VerifyPointers(); \
Isolate::Current()->heap()->Verify(); \
}
#define DEOPTIMIZE_ALOT \
if (FLAG_deoptimize_alot) { \
DeoptimizeFunctionsOnStack(); \
}
#else
#define CHECK_STACK_ALIGNMENT { }
#define VERIFY_ON_TRANSITION { }
#define DEOPTIMIZE_ALOT { }
#endif
#define TRACE_NATIVE_CALL(format, name) \
if (FLAG_trace_natives) { \
OS::Print("Calling native: " format "\n", name); \
}
// Class NativeArguments is used to access arguments passed in from
// generated dart code to a runtime function or a dart library native
// function. It is also used to set the return value if any at the slot
// reserved for return values.
// All runtime function/dart library native functions have the
// following signature:
// void function_name(NativeArguments arguments);
// Inside the function, arguments are accessed as follows:
// const Instance& arg0 = Instance::CheckedHandle(arguments.ArgAt(0));
// const Smi& arg1 = Smi::CheckedHandle(arguments.ArgAt(1));
// The return value is set as follows:
// arguments.SetReturn(result);
// NOTE: Since we pass 'this' as a pass-by-value argument in the stubs we don't
// have DISALLOW_COPY_AND_ASSIGN in the class definition and do not make it a
// subclass of ValueObject.
class NativeArguments {
public:
Thread* thread() const { return thread_; }
int ArgCount() const { return ArgcBits::decode(argc_tag_); }
RawObject* ArgAt(int index) const {
ASSERT((index >= 0) && (index < ArgCount()));
RawObject** arg_ptr = &((*argv_)[-index]);
// Tell MemorySanitizer the RawObject* was initialized (by generated code).
MSAN_UNPOISON(arg_ptr, kWordSize);
return *arg_ptr;
}
int NativeArgCount() const {
int function_bits = FunctionBits::decode(argc_tag_);
return ArgCount() - NumHiddenArgs(function_bits);
}
RawObject* NativeArg0() const {
int function_bits = FunctionBits::decode(argc_tag_);
if (function_bits == (kClosureFunctionBit | kInstanceFunctionBit)) {
// Retrieve the receiver from the context.
const Object& closure = Object::Handle(ArgAt(0));
const Context& context =
Context::Handle(Closure::context(Instance::Cast(closure)));
return context.At(0);
}
return ArgAt(NumHiddenArgs(function_bits));
}
RawObject* NativeArgAt(int index) const {
ASSERT((index >= 0) && (index < NativeArgCount()));
if (index == 0) {
return NativeArg0();
}
int function_bits = FunctionBits::decode(argc_tag_);
const int actual_index = index + NumHiddenArgs(function_bits);
return ArgAt(actual_index);
}
void SetReturn(const Object& value) const {
*retval_ = value.raw();
}
static intptr_t thread_offset() {
return OFFSET_OF(NativeArguments, thread_);
}
static intptr_t argc_tag_offset() {
return OFFSET_OF(NativeArguments, argc_tag_);
}
static intptr_t argv_offset() { return OFFSET_OF(NativeArguments, argv_); }
static intptr_t retval_offset() {
return OFFSET_OF(NativeArguments, retval_);
}
static intptr_t AutoSetupScopeMask() {
return AutoSetupScopeBits::mask_in_place();
}
static intptr_t ParameterCountForResolution(const Function& function) {
ASSERT(function.is_native());
ASSERT(!function.IsGenerativeConstructor()); // Not supported.
intptr_t count = function.NumParameters();
if (function.is_static() && function.IsClosureFunction()) {
// The closure object is hidden and not accessible from native code.
// However, if the function is an instance closure function, the captured
// receiver located in the context is made accessible in native code at
// index 0, thereby hidding the closure object at index 0.
count--;
}
return count;
}
static int ComputeArgcTag(const Function& function) {
ASSERT(function.is_native());
ASSERT(!function.IsGenerativeConstructor()); // Not supported.
int tag = ArgcBits::encode(function.NumParameters());
int function_bits = 0;
if (!function.is_static()) {
function_bits |= kInstanceFunctionBit;
}
if (function.IsClosureFunction()) {
function_bits |= kClosureFunctionBit;
}
tag = FunctionBits::update(function_bits, tag);
if (function.IsNativeAutoSetupScope()) {
tag = AutoSetupScopeBits::update(1, tag);
}
return tag;
}
private:
enum {
kInstanceFunctionBit = 1,
kClosureFunctionBit = 2,
};
enum ArgcTagBits {
kArgcBit = 0,
kArgcSize = 24,
kFunctionBit = 24,
kFunctionSize = 2,
kAutoSetupScopeBit = 26,
};
class ArgcBits : public BitField<int, kArgcBit, kArgcSize> {};
class FunctionBits : public BitField<int, kFunctionBit, kFunctionSize> {};
class AutoSetupScopeBits : public BitField<int, kAutoSetupScopeBit, 1> {};
friend class Api;
friend class BootstrapNatives;
friend class Simulator;
// Since this function is passed a RawObject directly, we need to be
// exceedingly careful when we use it. If there are any other side
// effects in the statement that may cause GC, it could lead to
// bugs.
void SetReturnUnsafe(RawObject* value) const {
*retval_ = value;
}
// Returns true if the arguments are those of an instance function call.
bool ToInstanceFunction() const {
return (FunctionBits::decode(argc_tag_) & kInstanceFunctionBit);
}
// Returns true if the arguments are those of a closure function call.
bool ToClosureFunction() const {
return (FunctionBits::decode(argc_tag_) & kClosureFunctionBit);
}
int NumHiddenArgs(int function_bits) const {
// For static closure functions, the closure at index 0 is hidden.
// In the instance closure function case, the receiver is accessed from
// the context and the closure at index 0 is hidden, so the apparent
// argument count remains unchanged.
if (function_bits == kClosureFunctionBit) {
return 1;
}
return 0;
}
Thread* thread_; // Current thread pointer.
int argc_tag_; // Encodes argument count and invoked native call type.
RawObject*(*argv_)[]; // Pointer to an array of arguments to runtime call.
RawObject** retval_; // Pointer to the return value area.
};
} // namespace dart
#endif // VM_NATIVE_ARGUMENTS_H_