runtime/vm/native_entry.cc - sdk - Git at Google

 // Copyright (c) 2011, 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.

 #include "vm/native_entry.h"

 #include "include/dart_api.h"

 #include "vm/bootstrap.h"
 #include "vm/code_patcher.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_state.h"
 #include "vm/heap/safepoint.h"
 #include "vm/native_symbol.h"
 #include "vm/object_store.h"
 #include "vm/reusable_handles.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 #include "vm/tags.h"

 namespace dart {

 void DartNativeThrowTypeArgumentCountException(int num_type_args,
                                                int num_type_args_expected) {
   const String& error = String::Handle(String::NewFormatted(
       "Wrong number of type arguments (%i), expected %i type arguments",
       num_type_args, num_type_args_expected));
   Exceptions::ThrowArgumentError(error);
 }

 void DartNativeThrowArgumentException(const Instance& instance) {
   const Array& __args__ = Array::Handle(Array::New(1));
   __args__.SetAt(0, instance);
   Exceptions::ThrowByType(Exceptions::kArgument, __args__);
 }

 NativeFunction NativeEntry::ResolveNative(const Library& library,
                                           const String& function_name,
                                           int number_of_arguments,
                                           bool* auto_setup_scope) {
   // Now resolve the native function to the corresponding native entrypoint.
   if (library.native_entry_resolver() == nullptr) {
     // Native methods are not allowed in the library to which this
     // class belongs in.
     return nullptr;
   }
   Dart_NativeFunction native_function = nullptr;
   {
     Thread* T = Thread::Current();
     Api::Scope api_scope(T);
     Dart_Handle api_function_name = Api::NewHandle(T, function_name.ptr());
     {
       Dart_NativeEntryResolver resolver = library.native_entry_resolver();
       TransitionVMToNative transition(T);
       native_function =
           resolver(api_function_name, number_of_arguments, auto_setup_scope);
     }
   }
   return reinterpret_cast<NativeFunction>(native_function);
 }

 const uint8_t* NativeEntry::ResolveSymbolInLibrary(const Library& library,
                                                    uword pc) {
   Dart_NativeEntrySymbol symbol_resolver =
       library.native_entry_symbol_resolver();
   if (symbol_resolver == nullptr) {
     // Cannot reverse lookup native entries.
     return nullptr;
   }
   return symbol_resolver(reinterpret_cast<Dart_NativeFunction>(pc));
 }

 const uint8_t* NativeEntry::ResolveSymbol(uword pc) {
   Thread* thread = Thread::Current();
   REUSABLE_GROWABLE_OBJECT_ARRAY_HANDLESCOPE(thread);
   GrowableObjectArray& libs = reused_growable_object_array_handle.Handle();
   libs = thread->isolate_group()->object_store()->libraries();
   ASSERT(!libs.IsNull());
   intptr_t num_libs = libs.Length();
   for (intptr_t i = 0; i < num_libs; i++) {
     REUSABLE_LIBRARY_HANDLESCOPE(thread);
     Library& lib = reused_library_handle.Handle();
     lib ^= libs.At(i);
     ASSERT(!lib.IsNull());
     const uint8_t* r = ResolveSymbolInLibrary(lib, pc);
     if (r != nullptr) {
       return r;
     }
   }
   return nullptr;
 }

 void NativeEntry::MaybePropagateError(NativeArguments* arguments) {
   Thread* thread = arguments->thread();

   // We must not access NativeArguments or the result's header under
   // the kThreadInNative state.
   ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
   ObjectPtr retval = arguments->ReturnValue();
   if (UNLIKELY(IsErrorClassId(retval->GetClassId()))) {
     thread->UnwindScopes(thread->top_exit_frame_info());

     TransitionGeneratedToVM transition(thread);

     // The thread->zone() is different here than before we unwound.
     const Object& error =
         Object::Handle(thread->zone(), arguments->ReturnValue());
     Exceptions::PropagateError(Error::Cast(error));
     UNREACHABLE();
   }
 }

 uword NativeEntry::BootstrapNativeCallWrapperEntry() {
   uword entry =
       reinterpret_cast<uword>(NativeEntry::BootstrapNativeCallWrapper);
 #if defined(USING_SIMULATOR)
   entry = Simulator::RedirectExternalReference(
       entry, Simulator::kNativeCallWrapper,
       NativeEntry::kNumCallWrapperArguments);
 #endif
   return entry;
 }

 void NativeEntry::BootstrapNativeCallWrapper(Dart_NativeArguments args,
                                              Dart_NativeFunction func) {
   CHECK_STACK_ALIGNMENT;
   if (func == LinkNativeCall) {
     func(args);
     return;
   }

   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   // Tell MemorySanitizer 'arguments' is initialized by generated code.
   MSAN_UNPOISON(arguments, sizeof(*arguments));
   {
     Thread* thread = arguments->thread();
     ASSERT(thread == Thread::Current());
     TransitionGeneratedToVM transition(thread);
     StackZone zone(thread);
     // Be careful holding return_value_unsafe without a handle here.
     // A return of Object::sentinel means the return value has already
     // been set.
     ObjectPtr return_value_unsafe = reinterpret_cast<BootstrapNativeFunction>(
         reinterpret_cast<void*>(func))(thread, zone.GetZone(), arguments);
     if (return_value_unsafe != Object::sentinel().ptr()) {
       ASSERT(return_value_unsafe->IsDartInstance());
       arguments->SetReturnUnsafe(return_value_unsafe);
     }
     DEOPTIMIZE_ALOT;
   }
 }

 uword NativeEntry::NoScopeNativeCallWrapperEntry() {
   uword entry = reinterpret_cast<uword>(NativeEntry::NoScopeNativeCallWrapper);
 #if defined(USING_SIMULATOR)
   entry = Simulator::RedirectExternalReference(
       entry, Simulator::kNativeCallWrapper,
       NativeEntry::kNumCallWrapperArguments);
 #endif
   return entry;
 }

 void NativeEntry::NoScopeNativeCallWrapper(Dart_NativeArguments args,
                                            Dart_NativeFunction func) {
   CHECK_STACK_ALIGNMENT;
   NoScopeNativeCallWrapperNoStackCheck(args, func);
 }

 void NativeEntry::NoScopeNativeCallWrapperNoStackCheck(
     Dart_NativeArguments args,
     Dart_NativeFunction func) {
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   // Tell MemorySanitizer 'arguments' is initialized by generated code.
   MSAN_UNPOISON(arguments, sizeof(*arguments));
   Thread* thread = arguments->thread();
   ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
   {
     TransitionGeneratedToNative transition(thread);
     func(args);
   }
   MaybePropagateError(arguments);
   ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
 }

 uword NativeEntry::AutoScopeNativeCallWrapperEntry() {
   uword entry =
       reinterpret_cast<uword>(NativeEntry::AutoScopeNativeCallWrapper);
 #if defined(USING_SIMULATOR)
   entry = Simulator::RedirectExternalReference(
       entry, Simulator::kNativeCallWrapper,
       NativeEntry::kNumCallWrapperArguments);
 #endif
   return entry;
 }

 void NativeEntry::AutoScopeNativeCallWrapper(Dart_NativeArguments args,
                                              Dart_NativeFunction func) {
   CHECK_STACK_ALIGNMENT;
   AutoScopeNativeCallWrapperNoStackCheck(args, func);
 }

 void NativeEntry::AutoScopeNativeCallWrapperNoStackCheck(
     Dart_NativeArguments args,
     Dart_NativeFunction func) {
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   // Tell MemorySanitizer 'arguments' is initialized by generated code.
   MSAN_UNPOISON(arguments, sizeof(*arguments));
   Thread* thread = arguments->thread();
   ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
   {
     Isolate* isolate = thread->isolate();
     ApiState* state = isolate->group()->api_state();
     ASSERT(state != nullptr);
     TRACE_NATIVE_CALL("0x%" Px "", reinterpret_cast<uintptr_t>(func));
     thread->EnterApiScope();
     {
       TransitionGeneratedToNative transition(thread);
       func(args);
     }
     MaybePropagateError(arguments);
     thread->ExitApiScope();
     DEOPTIMIZE_ALOT;
   }
   ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
 }

 static NativeFunction ResolveNativeFunction(Zone* zone,
                                             const Function& func,
                                             bool* is_bootstrap_native,
                                             bool* is_auto_scope) {
   const Class& cls = Class::Handle(zone, func.Owner());
   const Library& library = Library::Handle(zone, cls.library());

   *is_bootstrap_native =
       Bootstrap::IsBootstrapResolver(library.native_entry_resolver());

   const String& native_name = String::Handle(zone, func.native_name());
   ASSERT(!native_name.IsNull());

   const int num_params = NativeArguments::ParameterCountForResolution(func);
   NativeFunction native_function = NativeEntry::ResolveNative(
       library, native_name, num_params, is_auto_scope);
   if (native_function == nullptr) {
     FATAL("Failed to resolve native function '%s' in '%s'\n",
           native_name.ToCString(), func.ToQualifiedCString());
   }
   return native_function;
 }

 uword NativeEntry::LinkNativeCallEntry() {
   uword entry = reinterpret_cast<uword>(NativeEntry::LinkNativeCall);
   return entry;
 }

 void NativeEntry::LinkNativeCall(Dart_NativeArguments args) {
   CHECK_STACK_ALIGNMENT;
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   // Tell MemorySanitizer 'arguments' is initialized by generated code.
   MSAN_UNPOISON(arguments, sizeof(*arguments));
   TRACE_NATIVE_CALL("%s", "LinkNative");

   NativeFunction target_function = nullptr;
   bool is_bootstrap_native = false;
   bool is_auto_scope = true;

   {
     TransitionGeneratedToVM transition(arguments->thread());
     StackZone stack_zone(arguments->thread());
     Zone* zone = stack_zone.GetZone();

     DartFrameIterator iterator(arguments->thread(),
                                StackFrameIterator::kNoCrossThreadIteration);
     StackFrame* caller_frame = iterator.NextFrame();

     Code& code = Code::Handle(zone, caller_frame->LookupDartCode());
     Function& func = Function::Handle(zone, code.function());

     if (FLAG_trace_natives) {
       THR_Print("Resolving native target for %s\n", func.ToCString());
     }

     target_function =
         ResolveNativeFunction(arguments->thread()->zone(), func,
                               &is_bootstrap_native, &is_auto_scope);
     ASSERT(target_function != nullptr);

 #if defined(DEBUG)
     NativeFunction current_function = nullptr;
     const Code& current_trampoline =
         Code::Handle(zone, CodePatcher::GetNativeCallAt(
                                caller_frame->pc(), code, &current_function));
     // Some other isolate(with code being shared in AOT) might have updated
     // target function/trampoline already.
     ASSERT(current_function ==
                reinterpret_cast<NativeFunction>(LinkNativeCall) ||
            current_function == target_function);
     ASSERT(current_trampoline.ptr() == StubCode::CallBootstrapNative().ptr() ||
            current_function == target_function);
 #endif

     NativeFunction patch_target_function = target_function;
     Code& trampoline = Code::Handle(zone);
     if (is_bootstrap_native) {
       trampoline = StubCode::CallBootstrapNative().ptr();
     } else if (is_auto_scope) {
       trampoline = StubCode::CallAutoScopeNative().ptr();
     } else {
       trampoline = StubCode::CallNoScopeNative().ptr();
     }
     CodePatcher::PatchNativeCallAt(caller_frame->pc(), code,
                                    patch_target_function, trampoline);

     if (FLAG_trace_natives) {
       THR_Print("    -> %p (%s)\n", target_function,
                 is_bootstrap_native ? "bootstrap" : "non-bootstrap");
     }
   }

   // Tail-call resolved target.
   if (is_bootstrap_native) {
     NativeEntry::BootstrapNativeCallWrapper(
         args, reinterpret_cast<Dart_NativeFunction>(target_function));
   } else if (is_auto_scope) {
     // Because this call is within a compilation unit, Clang doesn't respect
     // the ABI alignment here.
     NativeEntry::AutoScopeNativeCallWrapperNoStackCheck(
         args, reinterpret_cast<Dart_NativeFunction>(target_function));
   } else {
     // Because this call is within a compilation unit, Clang doesn't respect
     // the ABI alignment here.
     NativeEntry::NoScopeNativeCallWrapperNoStackCheck(
         args, reinterpret_cast<Dart_NativeFunction>(target_function));
   }
 }

 #if !defined(DART_PRECOMPILED_RUNTIME)

 // Note: not GC safe. Use with care.
 NativeEntryData::Payload* NativeEntryData::FromTypedArray(TypedDataPtr data) {
   return reinterpret_cast<Payload*>(data->untag()->data());
 }

 MethodRecognizer::Kind NativeEntryData::kind() const {
   return FromTypedArray(data_.ptr())->kind;
 }

 void NativeEntryData::set_kind(MethodRecognizer::Kind value) const {
   FromTypedArray(data_.ptr())->kind = value;
 }

 MethodRecognizer::Kind NativeEntryData::GetKind(TypedDataPtr data) {
   return FromTypedArray(data)->kind;
 }

 NativeFunctionWrapper NativeEntryData::trampoline() const {
   return FromTypedArray(data_.ptr())->trampoline;
 }

 void NativeEntryData::set_trampoline(NativeFunctionWrapper value) const {
   FromTypedArray(data_.ptr())->trampoline = value;
 }

 NativeFunctionWrapper NativeEntryData::GetTrampoline(TypedDataPtr data) {
   return FromTypedArray(data)->trampoline;
 }

 NativeFunction NativeEntryData::native_function() const {
   return FromTypedArray(data_.ptr())->native_function;
 }

 void NativeEntryData::set_native_function(NativeFunction value) const {
   FromTypedArray(data_.ptr())->native_function = value;
 }

 NativeFunction NativeEntryData::GetNativeFunction(TypedDataPtr data) {
   return FromTypedArray(data)->native_function;
 }

 intptr_t NativeEntryData::argc_tag() const {
   return FromTypedArray(data_.ptr())->argc_tag;
 }

 void NativeEntryData::set_argc_tag(intptr_t value) const {
   FromTypedArray(data_.ptr())->argc_tag = value;
 }

 intptr_t NativeEntryData::GetArgcTag(TypedDataPtr data) {
   return FromTypedArray(data)->argc_tag;
 }

 TypedDataPtr NativeEntryData::New(MethodRecognizer::Kind kind,
                                   NativeFunctionWrapper trampoline,
                                   NativeFunction native_function,
                                   intptr_t argc_tag) {
   const TypedData& data = TypedData::Handle(
       TypedData::New(kTypedDataUint8ArrayCid, sizeof(Payload), Heap::kOld));
   NativeEntryData native_entry(data);
   native_entry.set_kind(kind);
   native_entry.set_trampoline(trampoline);
   native_entry.set_native_function(native_function);
   native_entry.set_argc_tag(argc_tag);
   return data.ptr();
 }

 #endif  // !defined(DART_PRECOMPILED_RUNTIME)

 }  // namespace dart
	// Copyright (c) 2011, 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.

	#include "vm/native_entry.h"

	#include "include/dart_api.h"

	#include "vm/bootstrap.h"
	#include "vm/code_patcher.h"
	#include "vm/dart_api_impl.h"
	#include "vm/dart_api_state.h"
	#include "vm/heap/safepoint.h"
	#include "vm/native_symbol.h"
	#include "vm/object_store.h"
	#include "vm/reusable_handles.h"
	#include "vm/stack_frame.h"
	#include "vm/symbols.h"
	#include "vm/tags.h"

	namespace dart {

	void DartNativeThrowTypeArgumentCountException(int num_type_args,
	int num_type_args_expected) {
	const String& error = String::Handle(String::NewFormatted(
	"Wrong number of type arguments (%i), expected %i type arguments",
	num_type_args, num_type_args_expected));
	Exceptions::ThrowArgumentError(error);
	}

	void DartNativeThrowArgumentException(const Instance& instance) {
	const Array& __args__ = Array::Handle(Array::New(1));
	__args__.SetAt(0, instance);
	Exceptions::ThrowByType(Exceptions::kArgument, __args__);
	}

	NativeFunction NativeEntry::ResolveNative(const Library& library,
	const String& function_name,
	int number_of_arguments,
	bool* auto_setup_scope) {
	// Now resolve the native function to the corresponding native entrypoint.
	if (library.native_entry_resolver() == nullptr) {
	// Native methods are not allowed in the library to which this
	// class belongs in.
	return nullptr;
	}
	Dart_NativeFunction native_function = nullptr;
	{
	Thread* T = Thread::Current();
	Api::Scope api_scope(T);
	Dart_Handle api_function_name = Api::NewHandle(T, function_name.ptr());
	{
	Dart_NativeEntryResolver resolver = library.native_entry_resolver();
	TransitionVMToNative transition(T);
	native_function =
	resolver(api_function_name, number_of_arguments, auto_setup_scope);
	}
	}
	return reinterpret_cast<NativeFunction>(native_function);
	}

	const uint8_t* NativeEntry::ResolveSymbolInLibrary(const Library& library,
	uword pc) {
	Dart_NativeEntrySymbol symbol_resolver =
	library.native_entry_symbol_resolver();
	if (symbol_resolver == nullptr) {
	// Cannot reverse lookup native entries.
	return nullptr;
	}
	return symbol_resolver(reinterpret_cast<Dart_NativeFunction>(pc));
	}

	const uint8_t* NativeEntry::ResolveSymbol(uword pc) {
	Thread* thread = Thread::Current();
	REUSABLE_GROWABLE_OBJECT_ARRAY_HANDLESCOPE(thread);
	GrowableObjectArray& libs = reused_growable_object_array_handle.Handle();
	libs = thread->isolate_group()->object_store()->libraries();
	ASSERT(!libs.IsNull());
	intptr_t num_libs = libs.Length();
	for (intptr_t i = 0; i < num_libs; i++) {
	REUSABLE_LIBRARY_HANDLESCOPE(thread);
	Library& lib = reused_library_handle.Handle();
	lib ^= libs.At(i);
	ASSERT(!lib.IsNull());
	const uint8_t* r = ResolveSymbolInLibrary(lib, pc);
	if (r != nullptr) {
	return r;
	}
	}
	return nullptr;
	}

	void NativeEntry::MaybePropagateError(NativeArguments* arguments) {
	Thread* thread = arguments->thread();

	// We must not access NativeArguments or the result's header under
	// the kThreadInNative state.
	ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
	ObjectPtr retval = arguments->ReturnValue();
	if (UNLIKELY(IsErrorClassId(retval->GetClassId()))) {
	thread->UnwindScopes(thread->top_exit_frame_info());

	TransitionGeneratedToVM transition(thread);

	// The thread->zone() is different here than before we unwound.
	const Object& error =
	Object::Handle(thread->zone(), arguments->ReturnValue());
	Exceptions::PropagateError(Error::Cast(error));
	UNREACHABLE();
	}
	}

	uword NativeEntry::BootstrapNativeCallWrapperEntry() {
	uword entry =
	reinterpret_cast<uword>(NativeEntry::BootstrapNativeCallWrapper);
	#if defined(USING_SIMULATOR)
	entry = Simulator::RedirectExternalReference(
	entry, Simulator::kNativeCallWrapper,
	NativeEntry::kNumCallWrapperArguments);
	#endif
	return entry;
	}

	void NativeEntry::BootstrapNativeCallWrapper(Dart_NativeArguments args,
	Dart_NativeFunction func) {
	CHECK_STACK_ALIGNMENT;
	if (func == LinkNativeCall) {
	func(args);
	return;
	}

	NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
	// Tell MemorySanitizer 'arguments' is initialized by generated code.
	MSAN_UNPOISON(arguments, sizeof(*arguments));
	{
	Thread* thread = arguments->thread();
	ASSERT(thread == Thread::Current());
	TransitionGeneratedToVM transition(thread);
	StackZone zone(thread);
	// Be careful holding return_value_unsafe without a handle here.
	// A return of Object::sentinel means the return value has already
	// been set.
	ObjectPtr return_value_unsafe = reinterpret_cast<BootstrapNativeFunction>(
	reinterpret_cast<void*>(func))(thread, zone.GetZone(), arguments);
	if (return_value_unsafe != Object::sentinel().ptr()) {
	ASSERT(return_value_unsafe->IsDartInstance());
	arguments->SetReturnUnsafe(return_value_unsafe);
	}
	DEOPTIMIZE_ALOT;
	}
	}

	uword NativeEntry::NoScopeNativeCallWrapperEntry() {
	uword entry = reinterpret_cast<uword>(NativeEntry::NoScopeNativeCallWrapper);
	#if defined(USING_SIMULATOR)
	entry = Simulator::RedirectExternalReference(
	entry, Simulator::kNativeCallWrapper,
	NativeEntry::kNumCallWrapperArguments);
	#endif
	return entry;
	}

	void NativeEntry::NoScopeNativeCallWrapper(Dart_NativeArguments args,
	Dart_NativeFunction func) {
	CHECK_STACK_ALIGNMENT;
	NoScopeNativeCallWrapperNoStackCheck(args, func);
	}

	void NativeEntry::NoScopeNativeCallWrapperNoStackCheck(
	Dart_NativeArguments args,
	Dart_NativeFunction func) {
	NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
	// Tell MemorySanitizer 'arguments' is initialized by generated code.
	MSAN_UNPOISON(arguments, sizeof(*arguments));
	Thread* thread = arguments->thread();
	ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
	{
	TransitionGeneratedToNative transition(thread);
	func(args);
	}
	MaybePropagateError(arguments);
	ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
	}

	uword NativeEntry::AutoScopeNativeCallWrapperEntry() {
	uword entry =
	reinterpret_cast<uword>(NativeEntry::AutoScopeNativeCallWrapper);
	#if defined(USING_SIMULATOR)
	entry = Simulator::RedirectExternalReference(
	entry, Simulator::kNativeCallWrapper,
	NativeEntry::kNumCallWrapperArguments);
	#endif
	return entry;
	}

	void NativeEntry::AutoScopeNativeCallWrapper(Dart_NativeArguments args,
	Dart_NativeFunction func) {
	CHECK_STACK_ALIGNMENT;
	AutoScopeNativeCallWrapperNoStackCheck(args, func);
	}

	void NativeEntry::AutoScopeNativeCallWrapperNoStackCheck(
	Dart_NativeArguments args,
	Dart_NativeFunction func) {
	NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
	// Tell MemorySanitizer 'arguments' is initialized by generated code.
	MSAN_UNPOISON(arguments, sizeof(*arguments));
	Thread* thread = arguments->thread();
	ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
	{
	Isolate* isolate = thread->isolate();
	ApiState* state = isolate->group()->api_state();
	ASSERT(state != nullptr);
	TRACE_NATIVE_CALL("0x%" Px "", reinterpret_cast<uintptr_t>(func));
	thread->EnterApiScope();
	{
	TransitionGeneratedToNative transition(thread);
	func(args);
	}
	MaybePropagateError(arguments);
	thread->ExitApiScope();
	DEOPTIMIZE_ALOT;
	}
	ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
	}

	static NativeFunction ResolveNativeFunction(Zone* zone,
	const Function& func,
	bool* is_bootstrap_native,
	bool* is_auto_scope) {
	const Class& cls = Class::Handle(zone, func.Owner());
	const Library& library = Library::Handle(zone, cls.library());

	*is_bootstrap_native =
	Bootstrap::IsBootstrapResolver(library.native_entry_resolver());

	const String& native_name = String::Handle(zone, func.native_name());
	ASSERT(!native_name.IsNull());

	const int num_params = NativeArguments::ParameterCountForResolution(func);
	NativeFunction native_function = NativeEntry::ResolveNative(
	library, native_name, num_params, is_auto_scope);
	if (native_function == nullptr) {
	FATAL("Failed to resolve native function '%s' in '%s'\n",
	native_name.ToCString(), func.ToQualifiedCString());
	}
	return native_function;
	}

	uword NativeEntry::LinkNativeCallEntry() {
	uword entry = reinterpret_cast<uword>(NativeEntry::LinkNativeCall);
	return entry;
	}

	void NativeEntry::LinkNativeCall(Dart_NativeArguments args) {
	CHECK_STACK_ALIGNMENT;
	NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
	// Tell MemorySanitizer 'arguments' is initialized by generated code.
	MSAN_UNPOISON(arguments, sizeof(*arguments));
	TRACE_NATIVE_CALL("%s", "LinkNative");

	NativeFunction target_function = nullptr;
	bool is_bootstrap_native = false;
	bool is_auto_scope = true;

	{
	TransitionGeneratedToVM transition(arguments->thread());
	StackZone stack_zone(arguments->thread());
	Zone* zone = stack_zone.GetZone();

	DartFrameIterator iterator(arguments->thread(),
	StackFrameIterator::kNoCrossThreadIteration);
	StackFrame* caller_frame = iterator.NextFrame();

	Code& code = Code::Handle(zone, caller_frame->LookupDartCode());
	Function& func = Function::Handle(zone, code.function());

	if (FLAG_trace_natives) {
	THR_Print("Resolving native target for %s\n", func.ToCString());
	}

	target_function =
	ResolveNativeFunction(arguments->thread()->zone(), func,
	&is_bootstrap_native, &is_auto_scope);
	ASSERT(target_function != nullptr);

	#if defined(DEBUG)
	NativeFunction current_function = nullptr;
	const Code& current_trampoline =
	Code::Handle(zone, CodePatcher::GetNativeCallAt(
	caller_frame->pc(), code, &current_function));
	// Some other isolate(with code being shared in AOT) might have updated
	// target function/trampoline already.
	ASSERT(current_function ==
	reinterpret_cast<NativeFunction>(LinkNativeCall) \|\|
	current_function == target_function);
	ASSERT(current_trampoline.ptr() == StubCode::CallBootstrapNative().ptr() \|\|
	current_function == target_function);
	#endif

	NativeFunction patch_target_function = target_function;
	Code& trampoline = Code::Handle(zone);
	if (is_bootstrap_native) {
	trampoline = StubCode::CallBootstrapNative().ptr();
	} else if (is_auto_scope) {
	trampoline = StubCode::CallAutoScopeNative().ptr();
	} else {
	trampoline = StubCode::CallNoScopeNative().ptr();
	}
	CodePatcher::PatchNativeCallAt(caller_frame->pc(), code,
	patch_target_function, trampoline);

	if (FLAG_trace_natives) {
	THR_Print(" -> %p (%s)\n", target_function,
	is_bootstrap_native ? "bootstrap" : "non-bootstrap");
	}
	}

	// Tail-call resolved target.
	if (is_bootstrap_native) {
	NativeEntry::BootstrapNativeCallWrapper(
	args, reinterpret_cast<Dart_NativeFunction>(target_function));
	} else if (is_auto_scope) {
	// Because this call is within a compilation unit, Clang doesn't respect
	// the ABI alignment here.
	NativeEntry::AutoScopeNativeCallWrapperNoStackCheck(
	args, reinterpret_cast<Dart_NativeFunction>(target_function));
	} else {
	// Because this call is within a compilation unit, Clang doesn't respect
	// the ABI alignment here.
	NativeEntry::NoScopeNativeCallWrapperNoStackCheck(
	args, reinterpret_cast<Dart_NativeFunction>(target_function));
	}
	}

	#if !defined(DART_PRECOMPILED_RUNTIME)

	// Note: not GC safe. Use with care.
	NativeEntryData::Payload* NativeEntryData::FromTypedArray(TypedDataPtr data) {
	return reinterpret_cast<Payload*>(data->untag()->data());
	}

	MethodRecognizer::Kind NativeEntryData::kind() const {
	return FromTypedArray(data_.ptr())->kind;
	}

	void NativeEntryData::set_kind(MethodRecognizer::Kind value) const {
	FromTypedArray(data_.ptr())->kind = value;
	}

	MethodRecognizer::Kind NativeEntryData::GetKind(TypedDataPtr data) {
	return FromTypedArray(data)->kind;
	}

	NativeFunctionWrapper NativeEntryData::trampoline() const {
	return FromTypedArray(data_.ptr())->trampoline;
	}

	void NativeEntryData::set_trampoline(NativeFunctionWrapper value) const {
	FromTypedArray(data_.ptr())->trampoline = value;
	}

	NativeFunctionWrapper NativeEntryData::GetTrampoline(TypedDataPtr data) {
	return FromTypedArray(data)->trampoline;
	}

	NativeFunction NativeEntryData::native_function() const {
	return FromTypedArray(data_.ptr())->native_function;
	}

	void NativeEntryData::set_native_function(NativeFunction value) const {
	FromTypedArray(data_.ptr())->native_function = value;
	}

	NativeFunction NativeEntryData::GetNativeFunction(TypedDataPtr data) {
	return FromTypedArray(data)->native_function;
	}

	intptr_t NativeEntryData::argc_tag() const {
	return FromTypedArray(data_.ptr())->argc_tag;
	}

	void NativeEntryData::set_argc_tag(intptr_t value) const {
	FromTypedArray(data_.ptr())->argc_tag = value;
	}

	intptr_t NativeEntryData::GetArgcTag(TypedDataPtr data) {
	return FromTypedArray(data)->argc_tag;
	}

	TypedDataPtr NativeEntryData::New(MethodRecognizer::Kind kind,
	NativeFunctionWrapper trampoline,
	NativeFunction native_function,
	intptr_t argc_tag) {
	const TypedData& data = TypedData::Handle(
	TypedData::New(kTypedDataUint8ArrayCid, sizeof(Payload), Heap::kOld));
	NativeEntryData native_entry(data);
	native_entry.set_kind(kind);
	native_entry.set_trampoline(trampoline);
	native_entry.set_native_function(native_function);
	native_entry.set_argc_tag(argc_tag);
	return data.ptr();
	}

	#endif // !defined(DART_PRECOMPILED_RUNTIME)

	} // namespace dart