Vyacheslav Egorov
7558644bd6
Also move deopt id computation logic into a separate class and add a comment explaining while deopt ids are incremented by 2. Change-Id: Ife489be7d10c7198a8e7adf9e97e0c516d78ea55 Reviewed-on: https://dart-review.googlesource.com/72685 Commit-Queue: Vyacheslav Egorov <vegorov@google.com> Reviewed-by: Martin Kustermann <kustermann@google.com>
108 lines
3.0 KiB
C++
108 lines
3.0 KiB
C++
// Copyright (c) 2018, 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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#ifndef RUNTIME_VM_COMPILER_COMPILER_STATE_H_
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#define RUNTIME_VM_COMPILER_COMPILER_STATE_H_
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#include "vm/compiler/cha.h"
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#include "vm/thread.h"
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namespace dart {
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// Deoptimization Id logic.
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//
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// Deoptimization ids are used to refer to deoptimization points, at which
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// control can enter unoptimized code from the optimized version of the code.
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//
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// Note: any instruction that does a call has two deoptimization points,
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// one before the call and one after the call - so that we could deoptimize
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// to either before or after the call depending on whether the same call
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// already occured in the optimized code (and potentially produced
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// observable side-effects) or not.
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//
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// To simplify implementation we always allocate two deopt ids (one for before
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// point and one for the after point).
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class DeoptId : public AllStatic {
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public:
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static constexpr intptr_t kNone = -1;
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static inline intptr_t Next(intptr_t deopt_id) { return deopt_id + kStep; }
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static inline intptr_t ToDeoptAfter(intptr_t deopt_id) {
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ASSERT(IsDeoptBefore(deopt_id));
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return deopt_id + kAfterOffset;
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}
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static inline bool IsDeoptBefore(intptr_t deopt_id) {
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return (deopt_id % kStep) == kBeforeOffset;
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}
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static inline bool IsDeoptAfter(intptr_t deopt_id) {
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return (deopt_id % kStep) == kAfterOffset;
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}
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private:
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static constexpr intptr_t kStep = 2;
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static constexpr intptr_t kBeforeOffset = 0;
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static constexpr intptr_t kAfterOffset = 1;
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};
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// Global compiler state attached to the thread.
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class CompilerState : public StackResource {
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public:
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explicit CompilerState(Thread* thread) : StackResource(thread), cha_(thread) {
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previous_ = thread->SetCompilerState(this);
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}
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~CompilerState() {
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ASSERT(&thread()->compiler_state() == this);
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thread()->SetCompilerState(previous_);
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}
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CHA& cha() { return cha_; }
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intptr_t deopt_id() const { return deopt_id_; }
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void set_deopt_id(int value) {
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ASSERT(value >= 0);
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deopt_id_ = value;
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}
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intptr_t GetNextDeoptId() {
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ASSERT(deopt_id_ != DeoptId::kNone);
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const intptr_t id = deopt_id_;
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deopt_id_ = DeoptId::Next(deopt_id_);
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return id;
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}
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static CompilerState& Current() {
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return Thread::Current()->compiler_state();
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}
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private:
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CHA cha_;
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intptr_t deopt_id_ = 0;
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CompilerState* previous_;
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};
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class DeoptIdScope : public StackResource {
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public:
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DeoptIdScope(Thread* thread, intptr_t deopt_id)
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: StackResource(thread),
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prev_deopt_id_(thread->compiler_state().deopt_id()) {
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thread->compiler_state().set_deopt_id(deopt_id);
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}
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~DeoptIdScope() { thread()->compiler_state().set_deopt_id(prev_deopt_id_); }
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private:
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const intptr_t prev_deopt_id_;
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DISALLOW_COPY_AND_ASSIGN(DeoptIdScope);
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};
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} // namespace dart
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#endif // RUNTIME_VM_COMPILER_COMPILER_STATE_H_
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