cd5ea74700
Made operator* return reference to the raw type, not pointer. New method 'get()' should be used when raw pointer is needed. Also removed useless inline modifier from the SmaprtPointer methods and added const modifier to the methods that don't change smart pointer. Made ~SmartPointerBase protected to avoid accidental calls of the non-virtual base class's destructor. drive-by: fixed use after free in src/factory.cc BUG=None LOG=N R=alph@chromium.org, svenpanne@chromium.org Review URL: https://codereview.chromium.org/101763003 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18275 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
130 lines
4.7 KiB
C++
130 lines
4.7 KiB
C++
// Copyright 2013 the V8 project authors. All rights reserved.
|
|
// Redistribution and use in source and binary forms, with or without
|
|
// modification, are permitted provided that the following conditions are
|
|
// met:
|
|
//
|
|
// * Redistributions of source code must retain the above copyright
|
|
// notice, this list of conditions and the following disclaimer.
|
|
// * Redistributions in binary form must reproduce the above
|
|
// copyright notice, this list of conditions and the following
|
|
// disclaimer in the documentation and/or other materials provided
|
|
// with the distribution.
|
|
// * Neither the name of Google Inc. nor the names of its
|
|
// contributors may be used to endorse or promote products derived
|
|
// from this software without specific prior written permission.
|
|
//
|
|
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
|
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
|
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
|
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
#include "hydrogen-dce.h"
|
|
#include "v8.h"
|
|
|
|
namespace v8 {
|
|
namespace internal {
|
|
|
|
void HDeadCodeEliminationPhase::MarkLive(
|
|
HValue* instr, ZoneList<HValue*>* worklist) {
|
|
if (instr->CheckFlag(HValue::kIsLive)) return; // Already live.
|
|
|
|
if (FLAG_trace_dead_code_elimination) PrintLive(NULL, instr);
|
|
|
|
// Transitively mark all inputs of live instructions live.
|
|
worklist->Add(instr, zone());
|
|
while (!worklist->is_empty()) {
|
|
HValue* instr = worklist->RemoveLast();
|
|
instr->SetFlag(HValue::kIsLive);
|
|
for (int i = 0; i < instr->OperandCount(); ++i) {
|
|
HValue* input = instr->OperandAt(i);
|
|
if (!input->CheckFlag(HValue::kIsLive)) {
|
|
input->SetFlag(HValue::kIsLive);
|
|
worklist->Add(input, zone());
|
|
if (FLAG_trace_dead_code_elimination) PrintLive(instr, input);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
void HDeadCodeEliminationPhase::PrintLive(HValue* ref, HValue* instr) {
|
|
HeapStringAllocator allocator;
|
|
StringStream stream(&allocator);
|
|
if (ref != NULL) {
|
|
ref->PrintTo(&stream);
|
|
} else {
|
|
stream.Add("root ");
|
|
}
|
|
stream.Add(" -> ");
|
|
instr->PrintTo(&stream);
|
|
PrintF("[MarkLive %s]\n", stream.ToCString().get());
|
|
}
|
|
|
|
|
|
void HDeadCodeEliminationPhase::MarkLiveInstructions() {
|
|
ZoneList<HValue*> worklist(10, zone());
|
|
|
|
// Transitively mark all live instructions, starting from roots.
|
|
for (int i = 0; i < graph()->blocks()->length(); ++i) {
|
|
HBasicBlock* block = graph()->blocks()->at(i);
|
|
for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
|
|
HInstruction* instr = it.Current();
|
|
if (instr->CannotBeEliminated()) MarkLive(instr, &worklist);
|
|
}
|
|
for (int j = 0; j < block->phis()->length(); j++) {
|
|
HPhi* phi = block->phis()->at(j);
|
|
if (phi->CannotBeEliminated()) MarkLive(phi, &worklist);
|
|
}
|
|
}
|
|
|
|
ASSERT(worklist.is_empty()); // Should have processed everything.
|
|
}
|
|
|
|
|
|
void HDeadCodeEliminationPhase::RemoveDeadInstructions() {
|
|
ZoneList<HPhi*> worklist(graph()->blocks()->length(), zone());
|
|
|
|
// Remove any instruction not marked kIsLive.
|
|
for (int i = 0; i < graph()->blocks()->length(); ++i) {
|
|
HBasicBlock* block = graph()->blocks()->at(i);
|
|
for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
|
|
HInstruction* instr = it.Current();
|
|
if (!instr->CheckFlag(HValue::kIsLive)) {
|
|
// Instruction has not been marked live, so remove it.
|
|
instr->DeleteAndReplaceWith(NULL);
|
|
} else {
|
|
// Clear the liveness flag to leave the graph clean for the next DCE.
|
|
instr->ClearFlag(HValue::kIsLive);
|
|
}
|
|
}
|
|
// Collect phis that are dead and remove them in the next pass.
|
|
for (int j = 0; j < block->phis()->length(); j++) {
|
|
HPhi* phi = block->phis()->at(j);
|
|
if (!phi->CheckFlag(HValue::kIsLive)) {
|
|
worklist.Add(phi, zone());
|
|
} else {
|
|
phi->ClearFlag(HValue::kIsLive);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Process phis separately to avoid simultaneously mutating the phi list.
|
|
while (!worklist.is_empty()) {
|
|
HPhi* phi = worklist.RemoveLast();
|
|
HBasicBlock* block = phi->block();
|
|
phi->DeleteAndReplaceWith(NULL);
|
|
if (phi->HasMergedIndex()) {
|
|
block->RecordDeletedPhi(phi->merged_index());
|
|
}
|
|
}
|
|
}
|
|
|
|
} } // namespace v8::internal
|