blob: 2ea19b71a892f9b958519c0f667e4e101dcc463c [file] [log] [blame]
// Copyright (c) 2017, 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/stack_trace.h"
#include "vm/dart_api_impl.h"
#include "vm/stack_frame.h"
#include "vm/symbols.h"
#if !defined(DART_PRECOMPILED_RUNTIME)
#include "vm/compiler/frontend/bytecode_reader.h"
#endif // !defined(DART_PRECOMPILED_RUNTIME)
namespace dart {
// Keep in sync with
// sdk/lib/async/stream_controller.dart:_StreamController._STATE_SUBSCRIBED.
const intptr_t kStreamController_StateSubscribed = 1;
ClosurePtr FindClosureInFrame(ObjectPtr* last_object_in_caller,
const Function& function,
bool is_interpreted) {
NoSafepointScope nsp;
// The callee has function signature
// :async_op([result, exception, stack])
// So we are guaranteed to
// a) have only tagged arguments on the stack until we find the :async_op
// closure, and
// b) find the async closure.
auto& closure = Closure::Handle();
for (intptr_t i = 0; i < 4; i++) {
// KBC builds the stack upwards instead of the usual downwards stack.
ObjectPtr arg = last_object_in_caller[(is_interpreted ? -i : i)];
if (arg->IsHeapObject() && arg->GetClassId() == kClosureCid) {
closure = Closure::RawCast(arg);
if (closure.function() == function.raw()) {
return closure.raw();
}
}
}
UNREACHABLE();
}
// Find current yield index from async closure.
// Async closures contains a variable, :await_jump_var that holds the index into
// async wrapper.
intptr_t GetYieldIndex(const Closure& receiver_closure) {
const auto& function = Function::Handle(receiver_closure.function());
if (!function.IsAsyncClosure() && !function.IsAsyncGenClosure()) {
return PcDescriptorsLayout::kInvalidYieldIndex;
}
const auto& await_jump_var =
Object::Handle(Context::Handle(receiver_closure.context())
.At(Context::kAwaitJumpVarIndex));
ASSERT(await_jump_var.IsSmi());
return Smi::Cast(await_jump_var).Value();
}
intptr_t FindPcOffset(const PcDescriptors& pc_descs, intptr_t yield_index) {
if (yield_index == PcDescriptorsLayout::kInvalidYieldIndex) {
return 0;
}
PcDescriptors::Iterator iter(pc_descs, PcDescriptorsLayout::kAnyKind);
while (iter.MoveNext()) {
if (iter.YieldIndex() == yield_index) {
return iter.PcOffset();
}
}
UNREACHABLE(); // If we cannot find it we have a bug.
}
#if !defined(DART_PRECOMPILED_RUNTIME)
intptr_t FindPcOffset(const Bytecode& bytecode, intptr_t yield_index) {
if (yield_index == PcDescriptorsLayout::kInvalidYieldIndex) {
return 0;
}
if (!bytecode.HasSourcePositions()) {
return 0;
}
intptr_t last_yield_point = 0;
kernel::BytecodeSourcePositionsIterator iter(Thread::Current()->zone(),
bytecode);
while (iter.MoveNext()) {
if (iter.IsYieldPoint()) {
last_yield_point++;
}
if (last_yield_point == yield_index) {
return iter.PcOffset();
}
}
UNREACHABLE(); // If we cannot find it we have a bug.
}
#endif
// Helper class for finding the closure of the caller.
// This is done via the _AsyncAwaitCompleter which holds a
// FutureResultOrListeners which in turn holds a callback.
class CallerClosureFinder {
public:
// Instance caches library and field references.
// This way we don't have to do the look-ups for every frame in the stack.
explicit CallerClosureFinder(Zone* zone)
: receiver_context_(Context::Handle(zone)),
receiver_function_(Function::Handle(zone)),
parent_function_(Function::Handle(zone)),
context_entry_(Object::Handle(zone)),
is_sync(Object::Handle(zone)),
future_(Object::Handle(zone)),
listener_(Object::Handle(zone)),
callback_(Object::Handle(zone)),
controller_(Object::Handle(zone)),
state_(Object::Handle(zone)),
var_data_(Object::Handle(zone)),
callback_instance_(Object::Handle(zone)),
future_impl_class(Class::Handle(zone)),
async_await_completer_class(Class::Handle(zone)),
future_listener_class(Class::Handle(zone)),
async_start_stream_controller_class(Class::Handle(zone)),
stream_controller_class(Class::Handle(zone)),
async_stream_controller_class(Class::Handle(zone)),
controller_subscription_class(Class::Handle(zone)),
buffering_stream_subscription_class(Class::Handle(zone)),
stream_iterator_class(Class::Handle(zone)),
completer_is_sync_field(Field::Handle(zone)),
completer_future_field(Field::Handle(zone)),
future_result_or_listeners_field(Field::Handle(zone)),
callback_field(Field::Handle(zone)),
controller_controller_field(Field::Handle(zone)),
var_data_field(Field::Handle(zone)),
state_field(Field::Handle(zone)),
on_data_field(Field::Handle(zone)),
state_data_field(Field::Handle(zone)) {
const auto& async_lib = Library::Handle(zone, Library::AsyncLibrary());
// Look up classes:
// - async:
future_impl_class =
async_lib.LookupClassAllowPrivate(Symbols::FutureImpl());
ASSERT(!future_impl_class.IsNull());
async_await_completer_class =
async_lib.LookupClassAllowPrivate(Symbols::_AsyncAwaitCompleter());
ASSERT(!async_await_completer_class.IsNull());
future_listener_class =
async_lib.LookupClassAllowPrivate(Symbols::_FutureListener());
ASSERT(!future_listener_class.IsNull());
// - async*:
async_start_stream_controller_class = async_lib.LookupClassAllowPrivate(
Symbols::_AsyncStarStreamController());
ASSERT(!async_start_stream_controller_class.IsNull());
stream_controller_class =
async_lib.LookupClassAllowPrivate(Symbols::_StreamController());
ASSERT(!stream_controller_class.IsNull());
async_stream_controller_class =
async_lib.LookupClassAllowPrivate(Symbols::_AsyncStreamController());
ASSERT(!async_stream_controller_class.IsNull());
controller_subscription_class =
async_lib.LookupClassAllowPrivate(Symbols::_ControllerSubscription());
ASSERT(!controller_subscription_class.IsNull());
buffering_stream_subscription_class = async_lib.LookupClassAllowPrivate(
Symbols::_BufferingStreamSubscription());
ASSERT(!buffering_stream_subscription_class.IsNull());
stream_iterator_class =
async_lib.LookupClassAllowPrivate(Symbols::_StreamIterator());
ASSERT(!stream_iterator_class.IsNull());
// Look up fields:
// - async:
completer_is_sync_field =
async_await_completer_class.LookupFieldAllowPrivate(Symbols::isSync());
ASSERT(!completer_is_sync_field.IsNull());
completer_future_field =
async_await_completer_class.LookupFieldAllowPrivate(Symbols::_future());
ASSERT(!completer_future_field.IsNull());
future_result_or_listeners_field =
future_impl_class.LookupFieldAllowPrivate(
Symbols::_resultOrListeners());
ASSERT(!future_result_or_listeners_field.IsNull());
callback_field =
future_listener_class.LookupFieldAllowPrivate(Symbols::callback());
ASSERT(!callback_field.IsNull());
// - async*:
controller_controller_field =
async_start_stream_controller_class.LookupFieldAllowPrivate(
Symbols::controller());
ASSERT(!controller_controller_field.IsNull());
state_field =
stream_controller_class.LookupFieldAllowPrivate(Symbols::_state());
ASSERT(!state_field.IsNull());
var_data_field =
stream_controller_class.LookupFieldAllowPrivate(Symbols::_varData());
ASSERT(!var_data_field.IsNull());
on_data_field = buffering_stream_subscription_class.LookupFieldAllowPrivate(
Symbols::_onData());
ASSERT(!on_data_field.IsNull());
state_data_field =
stream_iterator_class.LookupFieldAllowPrivate(Symbols::_stateData());
ASSERT(!state_data_field.IsNull());
}
ClosurePtr GetCallerInFutureImpl(const Object& future_) {
ASSERT(!future_.IsNull());
ASSERT(future_.GetClassId() == future_impl_class.id());
listener_ =
Instance::Cast(future_).GetField(future_result_or_listeners_field);
if (listener_.GetClassId() != future_listener_class.id()) {
return Closure::null();
}
callback_ = Instance::Cast(listener_).GetField(callback_field);
// This happens for e.g.: await f().catchError(..);
if (callback_.IsNull()) {
return Closure::null();
}
ASSERT(callback_.IsClosure());
return Closure::Cast(callback_).raw();
}
ClosurePtr FindCallerInAsyncClosure(const Context& receiver_context) {
context_entry_ = receiver_context.At(Context::kAsyncCompleterIndex);
ASSERT(context_entry_.IsInstance());
ASSERT(context_entry_.GetClassId() == async_await_completer_class.id());
const Instance& completer = Instance::Cast(context_entry_);
future_ = completer.GetField(completer_future_field);
return GetCallerInFutureImpl(future_);
}
ClosurePtr FindCallerInAsyncGenClosure(const Context& receiver_context) {
context_entry_ = receiver_context.At(Context::kControllerIndex);
ASSERT(context_entry_.IsInstance());
ASSERT(context_entry_.GetClassId() ==
async_start_stream_controller_class.id());
const Instance& controller = Instance::Cast(context_entry_);
controller_ = controller.GetField(controller_controller_field);
ASSERT(!controller_.IsNull());
ASSERT(controller_.GetClassId() == async_stream_controller_class.id());
state_ = Instance::Cast(controller_).GetField(state_field);
ASSERT(state_.IsSmi());
if (Smi::Cast(state_).Value() != kStreamController_StateSubscribed) {
return Closure::null();
}
// _StreamController._varData
var_data_ = Instance::Cast(controller_).GetField(var_data_field);
ASSERT(var_data_.GetClassId() == controller_subscription_class.id());
// _ControllerSubscription<T>/_BufferingStreamSubscription.<T>_onData
callback_ = Instance::Cast(var_data_).GetField(on_data_field);
ASSERT(callback_.IsClosure());
// If this is not the "_StreamIterator._onData" tear-off, we return the
// callback we found.
receiver_function_ = Closure::Cast(callback_).function();
if (!receiver_function_.IsImplicitInstanceClosureFunction() ||
receiver_function_.Owner() != stream_iterator_class.raw()) {
return Closure::Cast(callback_).raw();
}
// All implicit closure functions (tear-offs) have the "this" receiver
// captured.
receiver_context_ = Closure::Cast(callback_).context();
ASSERT(receiver_context_.num_variables() == 1);
callback_instance_ = receiver_context_.At(0);
ASSERT(callback_instance_.IsInstance());
// If the async* stream is await-for'd:
if (callback_instance_.GetClassId() == stream_iterator_class.id()) {
// _StreamIterator._stateData
future_ = Instance::Cast(callback_instance_).GetField(state_data_field);
return GetCallerInFutureImpl(future_);
}
UNREACHABLE(); // If no onData is found we have a bug.
}
ClosurePtr FindCaller(const Closure& receiver_closure) {
receiver_function_ = receiver_closure.function();
receiver_context_ = receiver_closure.context();
if (receiver_function_.IsAsyncClosure()) {
return FindCallerInAsyncClosure(receiver_context_);
} else if (receiver_function_.IsAsyncGenClosure()) {
return FindCallerInAsyncGenClosure(receiver_context_);
} else if (receiver_function_.IsLocalFunction()) {
parent_function_ = receiver_function_.parent_function();
if (parent_function_.recognized_kind() ==
MethodRecognizer::kFutureTimeout) {
context_entry_ =
receiver_context_.At(Context::kFutureTimeoutFutureIndex);
return GetCallerInFutureImpl(context_entry_);
} else if (parent_function_.recognized_kind() ==
MethodRecognizer::kFutureWait) {
receiver_context_ = receiver_context_.parent();
ASSERT(!receiver_context_.IsNull());
context_entry_ = receiver_context_.At(Context::kFutureWaitFutureIndex);
return GetCallerInFutureImpl(context_entry_);
}
}
return Closure::null();
}
bool IsRunningAsync(const Closure& receiver_closure) {
receiver_function_ = receiver_closure.function();
receiver_context_ = receiver_closure.context();
// The async* functions are never started synchronously, they start running
// after the first `listen()` call to its returned `Stream`.
if (receiver_function_.IsAsyncGenClosure()) {
return true;
}
ASSERT(receiver_function_.IsAsyncClosure());
context_entry_ = receiver_context_.At(Context::kAsyncCompleterIndex);
ASSERT(context_entry_.IsInstance());
ASSERT(context_entry_.GetClassId() == async_await_completer_class.id());
const Instance& completer = Instance::Cast(context_entry_);
is_sync = completer.GetField(completer_is_sync_field);
ASSERT(!is_sync.IsNull());
ASSERT(is_sync.IsBool());
// _AsyncAwaitCompleter.isSync indicates whether the future should be
// completed async. or sync., based on whether it has yielded yet.
// isSync is true when the :async_op is running async.
return Bool::Cast(is_sync).value();
}
private:
Context& receiver_context_;
Function& receiver_function_;
Function& parent_function_;
Object& context_entry_;
Object& is_sync;
Object& future_;
Object& listener_;
Object& callback_;
Object& controller_;
Object& state_;
Object& var_data_;
Object& callback_instance_;
Class& future_impl_class;
Class& async_await_completer_class;
Class& future_listener_class;
Class& async_start_stream_controller_class;
Class& stream_controller_class;
Class& async_stream_controller_class;
Class& controller_subscription_class;
Class& buffering_stream_subscription_class;
Class& stream_iterator_class;
Field& completer_is_sync_field;
Field& completer_future_field;
Field& future_result_or_listeners_field;
Field& callback_field;
Field& controller_controller_field;
Field& var_data_field;
Field& state_field;
Field& on_data_field;
Field& state_data_field;
};
void StackTraceUtils::CollectFramesLazy(
Thread* thread,
const GrowableObjectArray& code_array,
const GrowableObjectArray& pc_offset_array,
int skip_frames,
std::function<void(StackFrame*)>* on_sync_frames,
bool* has_async) {
if (has_async != nullptr) {
*has_async = false;
}
Zone* zone = thread->zone();
DartFrameIterator frames(thread, StackFrameIterator::kNoCrossThreadIteration);
StackFrame* frame = frames.NextFrame();
// If e.g. the isolate is paused before executing anything, we might not get
// any frames at all. Bail:
if (frame == nullptr) {
return;
}
auto& function = Function::Handle(zone);
auto& code = Code::Handle(zone);
auto& bytecode = Bytecode::Handle(zone);
auto& offset = Smi::Handle(zone);
auto& closure = Closure::Handle(zone);
CallerClosureFinder caller_closure_finder(zone);
auto& pc_descs = PcDescriptors::Handle();
// Start by traversing the sync. part of the stack.
for (; frame != nullptr; frame = frames.NextFrame()) {
if (skip_frames > 0) {
skip_frames--;
continue;
}
if (frame->is_interpreted()) {
bytecode = frame->LookupDartBytecode();
ASSERT(!bytecode.IsNull());
function = bytecode.function();
if (function.IsNull()) {
continue;
}
RELEASE_ASSERT(function.raw() == frame->LookupDartFunction());
} else {
function = frame->LookupDartFunction();
}
// Add the current synchronous frame.
if (frame->is_interpreted()) {
code_array.Add(bytecode);
const intptr_t pc_offset = frame->pc() - bytecode.PayloadStart();
ASSERT(pc_offset > 0 && pc_offset <= bytecode.Size());
offset = Smi::New(pc_offset);
} else {
code = frame->LookupDartCode();
ASSERT(function.raw() == code.function());
code_array.Add(code);
const intptr_t pc_offset = frame->pc() - code.PayloadStart();
ASSERT(pc_offset > 0 && pc_offset <= code.Size());
offset = Smi::New(pc_offset);
}
pc_offset_array.Add(offset);
if (on_sync_frames != nullptr) {
(*on_sync_frames)(frame);
}
// Either continue the loop (sync-async case) or find all await'ers and
// return.
if (!function.IsNull() &&
(function.IsAsyncClosure() || function.IsAsyncGenClosure())) {
if (has_async != nullptr) {
*has_async = true;
}
// Next, look up caller's closure on the stack and walk backwards through
// the yields.
ObjectPtr* last_caller_obj =
reinterpret_cast<ObjectPtr*>(frame->GetCallerSp());
closure = FindClosureInFrame(last_caller_obj, function,
frame->is_interpreted());
// If this async function hasn't yielded yet, we're still dealing with a
// normal stack. Continue to next frame as usual.
if (!caller_closure_finder.IsRunningAsync(closure)) {
continue;
}
// Inject async suspension marker.
code_array.Add(StubCode::AsynchronousGapMarker());
offset = Smi::New(0);
pc_offset_array.Add(offset);
// Skip: Already handled this frame's function above.
closure = caller_closure_finder.FindCaller(closure);
// Traverse the trail of async futures all the way up.
for (; !closure.IsNull();
closure = caller_closure_finder.FindCaller(closure)) {
function = closure.function();
// In hot-reload-test-mode we sometimes have to do this:
if (!function.HasCode() && !function.HasBytecode()) {
function.EnsureHasCode();
}
if (function.HasBytecode()) {
#if !defined(DART_PRECOMPILED_RUNTIME)
bytecode = function.bytecode();
code_array.Add(bytecode);
offset = Smi::New(FindPcOffset(bytecode, GetYieldIndex(closure)));
#else
UNREACHABLE();
#endif // !defined(DART_PRECOMPILED_RUNTIME)
} else if (function.HasCode()) {
code = function.CurrentCode();
code_array.Add(code);
pc_descs = code.pc_descriptors();
offset = Smi::New(FindPcOffset(pc_descs, GetYieldIndex(closure)));
} else {
UNREACHABLE();
}
// Unlike other sources of PC offsets, the offset may be 0 here if we
// reach a non-async closure receiving the yielded value.
ASSERT(offset.Value() >= 0);
pc_offset_array.Add(offset);
// Inject async suspension marker.
code_array.Add(StubCode::AsynchronousGapMarker());
offset = Smi::New(0);
pc_offset_array.Add(offset);
}
// Ignore the rest of the stack; already unwound all async calls.
return;
}
}
return;
}
// Count the number of frames that are on the stack.
intptr_t StackTraceUtils::CountFrames(Thread* thread,
int skip_frames,
const Function& async_function,
bool* sync_async_end) {
Zone* zone = thread->zone();
intptr_t frame_count = 0;
StackFrameIterator frames(ValidationPolicy::kDontValidateFrames, thread,
StackFrameIterator::kNoCrossThreadIteration);
StackFrame* frame = frames.NextFrame();
ASSERT(frame != NULL); // We expect to find a dart invocation frame.
Function& function = Function::Handle(zone);
Code& code = Code::Handle(zone);
Bytecode& bytecode = Bytecode::Handle(zone);
String& function_name = String::Handle(zone);
const bool async_function_is_null = async_function.IsNull();
int sync_async_gap_frames = -1;
ASSERT(async_function_is_null || sync_async_end != NULL);
for (; frame != NULL && sync_async_gap_frames != 0;
frame = frames.NextFrame()) {
if (!frame->IsDartFrame()) {
continue;
}
if (skip_frames > 0) {
skip_frames--;
continue;
}
if (frame->is_interpreted()) {
bytecode = frame->LookupDartBytecode();
function = bytecode.function();
if (function.IsNull()) continue;
} else {
code = frame->LookupDartCode();
function = code.function();
}
const bool function_is_null = function.IsNull();
if (!function_is_null && sync_async_gap_frames > 0) {
function_name = function.QualifiedScrubbedName();
if (!CheckAndSkipAsync(&sync_async_gap_frames, function_name)) {
*sync_async_end = false;
return frame_count;
}
} else {
frame_count++;
}
if (!async_function_is_null && !function_is_null &&
(async_function.raw() == function.parent_function())) {
sync_async_gap_frames = kSyncAsyncFrameGap;
}
}
if (!async_function_is_null) {
*sync_async_end = sync_async_gap_frames == 0;
}
return frame_count;
}
intptr_t StackTraceUtils::CollectFrames(Thread* thread,
const Array& code_array,
const Array& pc_offset_array,
intptr_t array_offset,
intptr_t count,
int skip_frames) {
Zone* zone = thread->zone();
StackFrameIterator frames(ValidationPolicy::kDontValidateFrames, thread,
StackFrameIterator::kNoCrossThreadIteration);
StackFrame* frame = frames.NextFrame();
ASSERT(frame != NULL); // We expect to find a dart invocation frame.
Function& function = Function::Handle(zone);
Code& code = Code::Handle(zone);
Bytecode& bytecode = Bytecode::Handle(zone);
Smi& offset = Smi::Handle(zone);
intptr_t collected_frames_count = 0;
for (; (frame != NULL) && (collected_frames_count < count);
frame = frames.NextFrame()) {
if (!frame->IsDartFrame()) {
continue;
}
if (skip_frames > 0) {
skip_frames--;
continue;
}
if (frame->is_interpreted()) {
bytecode = frame->LookupDartBytecode();
function = bytecode.function();
if (function.IsNull()) {
continue;
}
offset = Smi::New(frame->pc() - bytecode.PayloadStart());
code_array.SetAt(array_offset, bytecode);
} else {
code = frame->LookupDartCode();
offset = Smi::New(frame->pc() - code.PayloadStart());
code_array.SetAt(array_offset, code);
}
pc_offset_array.SetAt(array_offset, offset);
array_offset++;
collected_frames_count++;
}
return collected_frames_count;
}
intptr_t StackTraceUtils::ExtractAsyncStackTraceInfo(
Thread* thread,
Function* async_function,
StackTrace* async_stack_trace_out,
Array* async_code_array,
Array* async_pc_offset_array) {
if (thread->async_stack_trace() == StackTrace::null()) {
return 0;
}
*async_stack_trace_out = thread->async_stack_trace();
ASSERT(!async_stack_trace_out->IsNull());
const StackTrace& async_stack_trace =
StackTrace::Handle(thread->async_stack_trace());
const intptr_t async_stack_trace_length = async_stack_trace.Length();
// At least two entries (0: gap marker, 1: async function).
ASSERT(async_stack_trace_length >= 2);
// Validate the structure of this stack trace.
*async_code_array = async_stack_trace.code_array();
ASSERT(!async_code_array->IsNull());
*async_pc_offset_array = async_stack_trace.pc_offset_array();
ASSERT(!async_pc_offset_array->IsNull());
// We start with the asynchronous gap marker.
ASSERT(async_code_array->At(0) != Code::null());
ASSERT(async_code_array->At(0) == StubCode::AsynchronousGapMarker().raw());
const Object& code_object = Object::Handle(async_code_array->At(1));
if (code_object.IsCode()) {
*async_function = Code::Cast(code_object).function();
} else {
ASSERT(code_object.IsBytecode());
*async_function = Bytecode::Cast(code_object).function();
}
ASSERT(!async_function->IsNull());
ASSERT(async_function->IsAsyncFunction() ||
async_function->IsAsyncGenerator());
return async_stack_trace_length;
}
} // namespace dart