Ryan Macnak
7fd8ad5a2d
This reverts commit c7d7552697.
Reason for revert: https://github.com/dart-lang/sdk/issues/40780
Original change's description:
> [vm] Re-land aggressive write-barrier elimination.
>
> It incorrectly assumed that all stores in Dart code write to Instances.
> There is actually one exception, Contexts, which do not inherit from Instance.
>
> I've added asserts to ensure this kind of bug cannot resurface.
>
> The original change is in patchset 4.
>
> Change-Id: Ic2d8d05e70a4de738eb9fb5980487b4f27111b8c
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136221
> Commit-Queue: Samir Jindel <sjindel@google.com>
> Reviewed-by: Martin Kustermann <kustermann@google.com>
> Reviewed-by: Ryan Macnak <rmacnak@google.com>
TBR=kustermann@google.com,rmacnak@google.com,sjindel@google.com
# Not skipping CQ checks because original CL landed > 1 day ago.
Change-Id: I1891677b21560c7fc5a54a8eb800ef5850654402
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/137290
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
122 lines
2.8 KiB
C++
122 lines
2.8 KiB
C++
// Copyright (c) 2012, 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_BIT_VECTOR_H_
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#define RUNTIME_VM_BIT_VECTOR_H_
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#include "vm/allocation.h"
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#include "vm/isolate.h"
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#include "vm/zone.h"
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namespace dart {
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// Bit vector implementation.
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class BitVector : public ZoneAllocated {
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public:
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// Iterator for the elements of this BitVector.
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class Iterator : public ValueObject {
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public:
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explicit Iterator(BitVector* target)
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: target_(target),
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bit_index_(-1),
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word_index_(0),
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current_word_(target->data_[0]) {
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ASSERT(target->data_length_ > 0);
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Advance();
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}
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~Iterator() {}
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bool Done() const { return word_index_ >= target_->data_length_; }
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void Advance();
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intptr_t Current() const {
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ASSERT(!Done());
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return bit_index_;
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}
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private:
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BitVector* target_;
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intptr_t bit_index_;
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intptr_t word_index_;
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uword current_word_;
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friend class BitVector;
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};
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BitVector(Zone* zone, intptr_t length)
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: length_(length),
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data_length_(SizeFor(length)),
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data_(zone->Alloc<uword>(data_length_)) {
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Clear();
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}
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void CopyFrom(const BitVector* other) {
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Clear();
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AddAll(other);
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}
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static intptr_t SizeFor(intptr_t length) {
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return 1 + ((length - 1) / kBitsPerWord);
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}
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void Add(intptr_t i) {
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ASSERT(i >= 0 && i < length());
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data_[i / kBitsPerWord] |= (static_cast<uword>(1) << (i % kBitsPerWord));
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}
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void Remove(intptr_t i) {
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ASSERT(i >= 0 && i < length());
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data_[i / kBitsPerWord] &= ~(static_cast<uword>(1) << (i % kBitsPerWord));
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}
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bool Equals(const BitVector& other) const;
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// Add all elements that are in the bitvector from.
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bool AddAll(const BitVector* from);
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// Remove all elements that are in the bitvector from.
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bool RemoveAll(const BitVector* from);
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// From the bitvector gen add those elements that are not in the
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// bitvector kill.
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bool KillAndAdd(BitVector* kill, BitVector* gen);
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void Intersect(const BitVector* other);
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bool IsEmpty() const;
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bool Contains(intptr_t i) const {
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ASSERT(i >= 0 && i < length());
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uword block = data_[i / kBitsPerWord];
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return (block & (static_cast<uword>(1) << (i % kBitsPerWord))) != 0;
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}
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void Clear() {
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for (intptr_t i = 0; i < data_length_; i++) {
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data_[i] = 0;
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}
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}
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void SetAll() {
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for (intptr_t i = 0; i < data_length_; i++) {
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data_[i] = static_cast<uword>(-1);
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}
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}
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intptr_t length() const { return length_; }
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void Print() const;
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private:
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intptr_t length_;
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intptr_t data_length_;
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uword* data_;
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DISALLOW_COPY_AND_ASSIGN(BitVector);
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};
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} // namespace dart
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#endif // RUNTIME_VM_BIT_VECTOR_H_
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