Vyacheslav Egorov
7eed880d53
Instead of having special support for targeting catch entry as a lazy deoptimization target, split this into two independent operations: * Perform lazy deoptimization at call. * Rethrow the exception once deoptimization is complete. TEST=ci Change-Id: Ib275d615bc6717e1184e88602ae5459d5b771f2b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/361580 Reviewed-by: Alexander Aprelev <aam@google.com> Commit-Queue: Slava Egorov <vegorov@google.com>
117 lines
3.9 KiB
C++
117 lines
3.9 KiB
C++
// Copyright (c) 2021, 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 "vm/pending_deopts.h"
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#include "vm/log.h"
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#include "vm/stack_frame.h"
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#include "vm/stub_code.h"
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namespace dart {
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DECLARE_FLAG(bool, trace_deoptimization);
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PendingDeopts::PendingDeopts()
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: pending_deopts_(new MallocGrowableArray<PendingLazyDeopt>()) {}
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PendingDeopts::~PendingDeopts() {
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delete pending_deopts_;
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pending_deopts_ = nullptr;
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}
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void PendingDeopts::AddPendingDeopt(uword fp, uword pc) {
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// GrowableArray::Add is not atomic and may be interrupted by a profiler
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// stack walk.
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MallocGrowableArray<PendingLazyDeopt>* old_pending_deopts = pending_deopts_;
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MallocGrowableArray<PendingLazyDeopt>* new_pending_deopts =
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new MallocGrowableArray<PendingLazyDeopt>(old_pending_deopts->length() +
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1);
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for (intptr_t i = 0; i < old_pending_deopts->length(); i++) {
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ASSERT((*old_pending_deopts)[i].fp() != fp);
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new_pending_deopts->Add((*old_pending_deopts)[i]);
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}
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PendingLazyDeopt deopt(fp, pc);
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new_pending_deopts->Add(deopt);
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pending_deopts_ = new_pending_deopts;
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delete old_pending_deopts;
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}
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PendingLazyDeopt* PendingDeopts::FindPendingDeoptRecord(uword fp) {
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for (intptr_t i = 0; i < pending_deopts_->length(); i++) {
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if ((*pending_deopts_)[i].fp() == fp) {
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return &(*pending_deopts_)[i];
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}
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}
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return nullptr;
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}
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uword PendingDeopts::FindPendingDeopt(uword fp) {
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auto record = FindPendingDeoptRecord(fp);
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if (record != nullptr) {
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return record->pc();
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}
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FATAL("Missing pending deopt entry");
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return 0;
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}
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void PendingDeopts::ClearPendingDeoptsBelow(uword fp, ClearReason reason) {
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for (intptr_t i = pending_deopts_->length() - 1; i >= 0; i--) {
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if ((*pending_deopts_)[i].fp() < fp) {
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if (FLAG_trace_deoptimization) {
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switch (reason) {
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case kClearDueToThrow:
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THR_Print(
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"Lazy deopt skipped due to throw for "
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"fp=%" Pp ", pc=%" Pp "\n",
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(*pending_deopts_)[i].fp(), (*pending_deopts_)[i].pc());
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break;
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case kClearDueToDeopt:
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THR_Print("Lazy deopt fp=%" Pp " pc=%" Pp "\n",
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(*pending_deopts_)[i].fp(), (*pending_deopts_)[i].pc());
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break;
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}
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}
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pending_deopts_->RemoveAt(i);
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}
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}
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}
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void PendingDeopts::ClearPendingDeoptsAtOrBelow(uword fp, ClearReason reason) {
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ClearPendingDeoptsBelow(fp + kWordSize, reason);
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}
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uword PendingDeopts::RemapExceptionPCForDeopt(uword program_counter,
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uword frame_pointer,
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bool* clear_deopt) {
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*clear_deopt = false;
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// Do not attempt to deopt at async exception handler as it doesn't
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// belong to the function code. Async handler never continues execution
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// in the same frame - it either rethrows exception to the caller or
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// tail calls Dart handler, leaving the function frame before the call.
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if (program_counter == StubCode::AsyncExceptionHandler().EntryPoint()) {
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*clear_deopt = true;
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return program_counter;
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}
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// Check if the target frame is scheduled for lazy deopt.
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if (FindPendingDeoptRecord(frame_pointer) != nullptr) {
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#if defined(DEBUG)
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// Ensure the frame references optimized code.
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ObjectPtr pc_marker = *(reinterpret_cast<ObjectPtr*>(
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frame_pointer + runtime_frame_layout.code_from_fp * kWordSize));
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Code& code = Code::Handle(Code::RawCast(pc_marker));
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ASSERT(code.is_optimized() && !code.is_force_optimized());
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#endif
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if (FLAG_trace_deoptimization) {
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THR_Print("Throwing to frame scheduled for lazy deopt fp=%" Pp "\n",
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frame_pointer);
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}
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return StubCode::DeoptimizeLazyFromThrow().EntryPoint();
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}
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return program_counter;
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}
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} // namespace dart
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