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a52f2b9617
The main contribution of this CL is unification of disparate handling of various functions like `Future.timeout`, `Future.wait`, `_SuspendState.createAsyncCallbacks` and `_SuspendState._createAsyncStarCallback` into a single `@pragma('vm:awaiter-link')` which allows Dart developers to specify where awaiter unwinder should look for the next awaiter. For example this allows unwinding to succeed for the code like this: Future<int> outer(Future<int> inner) { @pragma('vm:awaiter-link') final completer = Completer<int>(); inner.then((v) => completer.complete(v)); return completer.future; } This refactoring also ensures that we preserve information (including Function & Code objects) required for awaiter unwinding across all modes (JIT, AOT and AOT with DWARF stack traces). This guarantees users will get the same information no matter which mode they are running in. Previously we have been disabling awaiter_stacks tests in some AOT modes - which led to regressions in the quality of produced stacks. This CL also cleans up relationship between debugger and awaiter stack returned by StackTrace.current - which makes stack trace displayed by debugger (used for stepping out and determinining whether exception is caught or not) and `StackTrace.current` consistent. Finally we make one user visible change to the stack trace: awaiter stack will no always include intermediate listeners created through `Future.then`. Previously we would sometimes include these listeners at the tail of the stack trace, which was inconsistent. Ultimately this means that code like this: Future<int> inner() async { await null; // asynchronous gap print(StackTrace.current); // (*) return 0; } Future<int> outer() async { int process(int v) { return v + 1; } return await inner().then(process); } void main() async { await outer(); } Produces stack trace like this: inner <asynchronous suspension> outer.process <asynchronous suspension> outer <asynchronous suspension> main <asynchronous suspension> And when stepping out of `inner` execution will stop at `outer.process` first and the next step out will bring execution to `outer` next. Fixes https://github.com/dart-lang/sdk/issues/52797 Fixes https://github.com/dart-lang/sdk/issues/52203 Issue https://github.com/dart-lang/sdk/issues/47985 TEST=ci Bug: b/279929839 CoreLibraryReviewExempt: CL just adds @pragma to facilitate unwinding Cq-Include-Trybots: luci.dart.try:vm-aot-linux-product-x64-try,vm-aot-linux-debug-x64-try,vm-aot-linux-release-x64-try,vm-aot-obfuscate-linux-release-x64-try,vm-aot-dwarf-linux-product-x64-try Change-Id: If377d5329d6a11c86effb9369dc603a7ae616fe7 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/311680 Reviewed-by: Alexander Markov <alexmarkov@google.com> Commit-Queue: Slava Egorov <vegorov@google.com>
115 lines
3.8 KiB
C++
115 lines
3.8 KiB
C++
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#include "lib/stacktrace.h"
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#include "vm/bootstrap_natives.h"
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#include "vm/debugger.h"
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#include "vm/exceptions.h"
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#include "vm/native_entry.h"
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#include "vm/object_store.h"
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#include "vm/runtime_entry.h"
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#include "vm/stack_frame.h"
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#include "vm/stack_trace.h"
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namespace dart {
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DECLARE_FLAG(bool, show_invisible_frames);
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static constexpr intptr_t kDefaultStackAllocation = 8;
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static StackTracePtr CreateStackTraceObject(
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Zone* zone,
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const GrowableObjectArray& code_list,
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const GrowableArray<uword>& pc_offset_list) {
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const auto& code_array =
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Array::Handle(zone, Array::MakeFixedLength(code_list));
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const auto& pc_offset_array = TypedData::Handle(
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zone, TypedData::New(kUintPtrCid, pc_offset_list.length()));
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{
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NoSafepointScope no_safepoint;
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memmove(pc_offset_array.DataAddr(0), pc_offset_list.data(),
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pc_offset_list.length() * kWordSize);
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}
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return StackTrace::New(code_array, pc_offset_array);
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}
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// Gets current stack trace for `thread`.
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static StackTracePtr CurrentStackTrace(Thread* thread,
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intptr_t skip_frames = 1) {
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Zone* zone = thread->zone();
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const auto& code_array = GrowableObjectArray::ZoneHandle(
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zone, GrowableObjectArray::New(kDefaultStackAllocation));
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GrowableArray<uword> pc_offset_array(kDefaultStackAllocation);
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// Collect the frames.
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StackTraceUtils::CollectFrames(thread, skip_frames,
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[&](const StackTraceUtils::Frame& frame) {
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code_array.Add(frame.code);
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pc_offset_array.Add(frame.pc_offset);
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});
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return CreateStackTraceObject(zone, code_array, pc_offset_array);
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}
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StackTracePtr GetStackTraceForException() {
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Thread* thread = Thread::Current();
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return CurrentStackTrace(thread, 0);
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}
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DEFINE_NATIVE_ENTRY(StackTrace_current, 0, 0) {
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return CurrentStackTrace(thread);
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}
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static void AppendFrames(const GrowableObjectArray& code_list,
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GrowableArray<uword>* pc_offset_list,
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int skip_frames) {
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Thread* thread = Thread::Current();
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Zone* zone = thread->zone();
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StackFrameIterator frames(ValidationPolicy::kDontValidateFrames, thread,
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StackFrameIterator::kNoCrossThreadIteration);
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StackFrame* frame = frames.NextFrame();
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ASSERT(frame != nullptr); // We expect to find a dart invocation frame.
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Code& code = Code::Handle(zone);
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for (; frame != nullptr; frame = frames.NextFrame()) {
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if (!frame->IsDartFrame()) {
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continue;
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}
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if (skip_frames > 0) {
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skip_frames--;
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continue;
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}
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code = frame->LookupDartCode();
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const intptr_t pc_offset = frame->pc() - code.PayloadStart();
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code_list.Add(code);
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pc_offset_list->Add(pc_offset);
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}
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}
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// Creates a StackTrace object from the current stack.
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//
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// Skips the first skip_frames Dart frames.
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const StackTrace& GetCurrentStackTrace(int skip_frames) {
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Zone* zone = Thread::Current()->zone();
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const GrowableObjectArray& code_list =
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GrowableObjectArray::Handle(zone, GrowableObjectArray::New());
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GrowableArray<uword> pc_offset_list;
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AppendFrames(code_list, &pc_offset_list, skip_frames);
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const StackTrace& stacktrace = StackTrace::Handle(
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zone, CreateStackTraceObject(zone, code_list, pc_offset_list));
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return stacktrace;
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}
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bool HasStack() {
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Thread* thread = Thread::Current();
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StackFrameIterator frames(ValidationPolicy::kDontValidateFrames, thread,
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StackFrameIterator::kNoCrossThreadIteration);
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StackFrame* frame = frames.NextFrame();
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return frame != nullptr;
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}
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} // namespace dart
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