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87 lines
2.8 KiB
87 lines
2.8 KiB
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "x86_memory_gen.h"
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#include "code_generator.h"
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#include "driver/compiler_options.h"
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namespace art {
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namespace x86 {
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/**
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* Replace instructions with memory operand forms.
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*/
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class MemoryOperandVisitor : public HGraphVisitor {
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public:
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MemoryOperandVisitor(HGraph* graph, bool do_implicit_null_checks)
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: HGraphVisitor(graph),
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do_implicit_null_checks_(do_implicit_null_checks) {}
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private:
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void VisitBoundsCheck(HBoundsCheck* check) override {
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// Replace the length by the array itself, so that we can do compares to memory.
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HArrayLength* array_len = check->InputAt(1)->AsArrayLength();
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// We only want to replace an ArrayLength.
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if (array_len == nullptr) {
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return;
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}
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HInstruction* array = array_len->InputAt(0);
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DCHECK_EQ(array->GetType(), DataType::Type::kReference);
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// Don't apply this optimization when the array is nullptr.
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if (array->IsConstant() || (array->IsNullCheck() && array->InputAt(0)->IsConstant())) {
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return;
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}
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// Is there a null check that could be an implicit check?
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if (array->IsNullCheck() && do_implicit_null_checks_) {
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// The ArrayLen may generate the implicit null check. Can the
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// bounds check do so as well?
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if (array_len->GetNextDisregardingMoves() != check) {
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// No, it won't. Leave as is.
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return;
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}
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}
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// Can we suppress the ArrayLength and generate at BoundCheck?
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if (array_len->HasOnlyOneNonEnvironmentUse()) {
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array_len->MarkEmittedAtUseSite();
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// We need the ArrayLength just before the BoundsCheck.
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array_len->MoveBefore(check);
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}
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}
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bool do_implicit_null_checks_;
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};
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X86MemoryOperandGeneration::X86MemoryOperandGeneration(HGraph* graph,
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CodeGenerator* codegen,
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OptimizingCompilerStats* stats)
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: HOptimization(graph, kX86MemoryOperandGenerationPassName, stats),
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do_implicit_null_checks_(codegen->GetCompilerOptions().GetImplicitNullChecks()) {
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}
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bool X86MemoryOperandGeneration::Run() {
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MemoryOperandVisitor visitor(graph_, do_implicit_null_checks_);
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visitor.VisitInsertionOrder();
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return true;
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}
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} // namespace x86
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} // namespace art
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