upload android base code part3
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688
android/art/compiler/optimizing/ssa_builder.cc
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688
android/art/compiler/optimizing/ssa_builder.cc
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/*
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* Copyright (C) 2014 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 "ssa_builder.h"
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#include "bytecode_utils.h"
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#include "mirror/class-inl.h"
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#include "nodes.h"
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#include "reference_type_propagation.h"
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#include "scoped_thread_state_change-inl.h"
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#include "ssa_phi_elimination.h"
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namespace art {
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void SsaBuilder::FixNullConstantType() {
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// The order doesn't matter here.
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for (HBasicBlock* block : graph_->GetReversePostOrder()) {
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for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
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HInstruction* equality_instr = it.Current();
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if (!equality_instr->IsEqual() && !equality_instr->IsNotEqual()) {
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continue;
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}
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HInstruction* left = equality_instr->InputAt(0);
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HInstruction* right = equality_instr->InputAt(1);
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HInstruction* int_operand = nullptr;
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if ((left->GetType() == Primitive::kPrimNot) && (right->GetType() == Primitive::kPrimInt)) {
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int_operand = right;
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} else if ((right->GetType() == Primitive::kPrimNot)
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&& (left->GetType() == Primitive::kPrimInt)) {
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int_operand = left;
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} else {
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continue;
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}
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// If we got here, we are comparing against a reference and the int constant
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// should be replaced with a null constant.
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// Both type propagation and redundant phi elimination ensure `int_operand`
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// can only be the 0 constant.
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DCHECK(int_operand->IsIntConstant()) << int_operand->DebugName();
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DCHECK_EQ(0, int_operand->AsIntConstant()->GetValue());
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equality_instr->ReplaceInput(graph_->GetNullConstant(), int_operand == right ? 1 : 0);
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}
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}
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}
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void SsaBuilder::EquivalentPhisCleanup() {
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// The order doesn't matter here.
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for (HBasicBlock* block : graph_->GetReversePostOrder()) {
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for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
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HPhi* phi = it.Current()->AsPhi();
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HPhi* next = phi->GetNextEquivalentPhiWithSameType();
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if (next != nullptr) {
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// Make sure we do not replace a live phi with a dead phi. A live phi
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// has been handled by the type propagation phase, unlike a dead phi.
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if (next->IsLive()) {
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phi->ReplaceWith(next);
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phi->SetDead();
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} else {
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next->ReplaceWith(phi);
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}
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DCHECK(next->GetNextEquivalentPhiWithSameType() == nullptr)
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<< "More then one phi equivalent with type " << phi->GetType()
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<< " found for phi" << phi->GetId();
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}
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}
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}
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}
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void SsaBuilder::FixEnvironmentPhis() {
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for (HBasicBlock* block : graph_->GetReversePostOrder()) {
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for (HInstructionIterator it_phis(block->GetPhis()); !it_phis.Done(); it_phis.Advance()) {
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HPhi* phi = it_phis.Current()->AsPhi();
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// If the phi is not dead, or has no environment uses, there is nothing to do.
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if (!phi->IsDead() || !phi->HasEnvironmentUses()) continue;
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HInstruction* next = phi->GetNext();
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if (!phi->IsVRegEquivalentOf(next)) continue;
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if (next->AsPhi()->IsDead()) {
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// If the phi equivalent is dead, check if there is another one.
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next = next->GetNext();
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if (!phi->IsVRegEquivalentOf(next)) continue;
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// There can be at most two phi equivalents.
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DCHECK(!phi->IsVRegEquivalentOf(next->GetNext()));
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if (next->AsPhi()->IsDead()) continue;
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}
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// We found a live phi equivalent. Update the environment uses of `phi` with it.
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phi->ReplaceWith(next);
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}
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}
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}
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static void AddDependentInstructionsToWorklist(HInstruction* instruction,
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ArenaVector<HPhi*>* worklist) {
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// If `instruction` is a dead phi, type conflict was just identified. All its
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// live phi users, and transitively users of those users, therefore need to be
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// marked dead/conflicting too, so we add them to the worklist. Otherwise we
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// add users whose type does not match and needs to be updated.
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bool add_all_live_phis = instruction->IsPhi() && instruction->AsPhi()->IsDead();
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for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) {
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HInstruction* user = use.GetUser();
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if (user->IsPhi() && user->AsPhi()->IsLive()) {
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if (add_all_live_phis || user->GetType() != instruction->GetType()) {
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worklist->push_back(user->AsPhi());
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}
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}
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}
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}
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// Find a candidate primitive type for `phi` by merging the type of its inputs.
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// Return false if conflict is identified.
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static bool TypePhiFromInputs(HPhi* phi) {
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Primitive::Type common_type = phi->GetType();
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for (HInstruction* input : phi->GetInputs()) {
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if (input->IsPhi() && input->AsPhi()->IsDead()) {
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// Phis are constructed live so if an input is a dead phi, it must have
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// been made dead due to type conflict. Mark this phi conflicting too.
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return false;
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}
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Primitive::Type input_type = HPhi::ToPhiType(input->GetType());
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if (common_type == input_type) {
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// No change in type.
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} else if (Primitive::Is64BitType(common_type) != Primitive::Is64BitType(input_type)) {
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// Types are of different sizes, e.g. int vs. long. Must be a conflict.
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return false;
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} else if (Primitive::IsIntegralType(common_type)) {
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// Previous inputs were integral, this one is not but is of the same size.
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// This does not imply conflict since some bytecode instruction types are
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// ambiguous. TypeInputsOfPhi will either type them or detect a conflict.
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DCHECK(Primitive::IsFloatingPointType(input_type) || input_type == Primitive::kPrimNot);
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common_type = input_type;
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} else if (Primitive::IsIntegralType(input_type)) {
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// Input is integral, common type is not. Same as in the previous case, if
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// there is a conflict, it will be detected during TypeInputsOfPhi.
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DCHECK(Primitive::IsFloatingPointType(common_type) || common_type == Primitive::kPrimNot);
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} else {
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// Combining float and reference types. Clearly a conflict.
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DCHECK((common_type == Primitive::kPrimFloat && input_type == Primitive::kPrimNot) ||
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(common_type == Primitive::kPrimNot && input_type == Primitive::kPrimFloat));
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return false;
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}
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}
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// We have found a candidate type for the phi. Set it and return true. We may
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// still discover conflict whilst typing the individual inputs in TypeInputsOfPhi.
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phi->SetType(common_type);
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return true;
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}
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// Replace inputs of `phi` to match its type. Return false if conflict is identified.
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bool SsaBuilder::TypeInputsOfPhi(HPhi* phi, ArenaVector<HPhi*>* worklist) {
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Primitive::Type common_type = phi->GetType();
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if (Primitive::IsIntegralType(common_type)) {
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// We do not need to retype ambiguous inputs because they are always constructed
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// with the integral type candidate.
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if (kIsDebugBuild) {
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for (HInstruction* input : phi->GetInputs()) {
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DCHECK(HPhi::ToPhiType(input->GetType()) == common_type);
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}
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}
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// Inputs did not need to be replaced, hence no conflict. Report success.
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return true;
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} else {
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DCHECK(common_type == Primitive::kPrimNot || Primitive::IsFloatingPointType(common_type));
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HInputsRef inputs = phi->GetInputs();
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for (size_t i = 0; i < inputs.size(); ++i) {
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HInstruction* input = inputs[i];
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if (input->GetType() != common_type) {
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// Input type does not match phi's type. Try to retype the input or
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// generate a suitably typed equivalent.
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HInstruction* equivalent = (common_type == Primitive::kPrimNot)
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? GetReferenceTypeEquivalent(input)
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: GetFloatOrDoubleEquivalent(input, common_type);
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if (equivalent == nullptr) {
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// Input could not be typed. Report conflict.
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return false;
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}
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// Make sure the input did not change its type and we do not need to
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// update its users.
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DCHECK_NE(input, equivalent);
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phi->ReplaceInput(equivalent, i);
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if (equivalent->IsPhi()) {
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worklist->push_back(equivalent->AsPhi());
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}
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}
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}
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// All inputs either matched the type of the phi or we successfully replaced
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// them with a suitable equivalent. Report success.
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return true;
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}
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}
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// Attempt to set the primitive type of `phi` to match its inputs. Return whether
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// it was changed by the algorithm or not.
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bool SsaBuilder::UpdatePrimitiveType(HPhi* phi, ArenaVector<HPhi*>* worklist) {
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DCHECK(phi->IsLive());
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Primitive::Type original_type = phi->GetType();
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// Try to type the phi in two stages:
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// (1) find a candidate type for the phi by merging types of all its inputs,
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// (2) try to type the phi's inputs to that candidate type.
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// Either of these stages may detect a type conflict and fail, in which case
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// we immediately abort.
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if (!TypePhiFromInputs(phi) || !TypeInputsOfPhi(phi, worklist)) {
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// Conflict detected. Mark the phi dead and return true because it changed.
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phi->SetDead();
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return true;
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}
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// Return true if the type of the phi has changed.
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return phi->GetType() != original_type;
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}
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void SsaBuilder::RunPrimitiveTypePropagation() {
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ArenaVector<HPhi*> worklist(graph_->GetArena()->Adapter(kArenaAllocGraphBuilder));
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for (HBasicBlock* block : graph_->GetReversePostOrder()) {
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if (block->IsLoopHeader()) {
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for (HInstructionIterator phi_it(block->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
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HPhi* phi = phi_it.Current()->AsPhi();
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if (phi->IsLive()) {
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worklist.push_back(phi);
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}
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}
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} else {
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for (HInstructionIterator phi_it(block->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
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// Eagerly compute the type of the phi, for quicker convergence. Note
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// that we don't need to add users to the worklist because we are
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// doing a reverse post-order visit, therefore either the phi users are
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// non-loop phi and will be visited later in the visit, or are loop-phis,
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// and they are already in the work list.
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HPhi* phi = phi_it.Current()->AsPhi();
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if (phi->IsLive()) {
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UpdatePrimitiveType(phi, &worklist);
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}
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}
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}
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}
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ProcessPrimitiveTypePropagationWorklist(&worklist);
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EquivalentPhisCleanup();
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}
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void SsaBuilder::ProcessPrimitiveTypePropagationWorklist(ArenaVector<HPhi*>* worklist) {
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// Process worklist
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while (!worklist->empty()) {
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HPhi* phi = worklist->back();
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worklist->pop_back();
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// The phi could have been made dead as a result of conflicts while in the
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// worklist. If it is now dead, there is no point in updating its type.
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if (phi->IsLive() && UpdatePrimitiveType(phi, worklist)) {
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AddDependentInstructionsToWorklist(phi, worklist);
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}
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}
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}
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static HArrayGet* FindFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) {
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Primitive::Type type = aget->GetType();
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DCHECK(Primitive::IsIntOrLongType(type));
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HInstruction* next = aget->GetNext();
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if (next != nullptr && next->IsArrayGet()) {
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HArrayGet* next_aget = next->AsArrayGet();
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if (next_aget->IsEquivalentOf(aget)) {
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return next_aget;
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}
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}
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return nullptr;
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}
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static HArrayGet* CreateFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) {
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Primitive::Type type = aget->GetType();
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DCHECK(Primitive::IsIntOrLongType(type));
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DCHECK(FindFloatOrDoubleEquivalentOfArrayGet(aget) == nullptr);
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HArrayGet* equivalent = new (aget->GetBlock()->GetGraph()->GetArena()) HArrayGet(
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aget->GetArray(),
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aget->GetIndex(),
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type == Primitive::kPrimInt ? Primitive::kPrimFloat : Primitive::kPrimDouble,
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aget->GetDexPc());
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aget->GetBlock()->InsertInstructionAfter(equivalent, aget);
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return equivalent;
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}
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static Primitive::Type GetPrimitiveArrayComponentType(HInstruction* array)
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REQUIRES_SHARED(Locks::mutator_lock_) {
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ReferenceTypeInfo array_type = array->GetReferenceTypeInfo();
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DCHECK(array_type.IsPrimitiveArrayClass());
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return array_type.GetTypeHandle()->GetComponentType()->GetPrimitiveType();
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}
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bool SsaBuilder::FixAmbiguousArrayOps() {
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if (ambiguous_agets_.empty() && ambiguous_asets_.empty()) {
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return true;
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}
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// The wrong ArrayGet equivalent may still have Phi uses coming from ArraySet
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// uses (because they are untyped) and environment uses (if --debuggable).
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// After resolving all ambiguous ArrayGets, we will re-run primitive type
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// propagation on the Phis which need to be updated.
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ArenaVector<HPhi*> worklist(graph_->GetArena()->Adapter(kArenaAllocGraphBuilder));
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{
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ScopedObjectAccess soa(Thread::Current());
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for (HArrayGet* aget_int : ambiguous_agets_) {
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HInstruction* array = aget_int->GetArray();
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if (!array->GetReferenceTypeInfo().IsPrimitiveArrayClass()) {
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// RTP did not type the input array. Bail.
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return false;
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}
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HArrayGet* aget_float = FindFloatOrDoubleEquivalentOfArrayGet(aget_int);
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Primitive::Type array_type = GetPrimitiveArrayComponentType(array);
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DCHECK_EQ(Primitive::Is64BitType(aget_int->GetType()), Primitive::Is64BitType(array_type));
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if (Primitive::IsIntOrLongType(array_type)) {
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if (aget_float != nullptr) {
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// There is a float/double equivalent. We must replace it and re-run
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// primitive type propagation on all dependent instructions.
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aget_float->ReplaceWith(aget_int);
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aget_float->GetBlock()->RemoveInstruction(aget_float);
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AddDependentInstructionsToWorklist(aget_int, &worklist);
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}
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} else {
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DCHECK(Primitive::IsFloatingPointType(array_type));
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if (aget_float == nullptr) {
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// This is a float/double ArrayGet but there were no typed uses which
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// would create the typed equivalent. Create it now.
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aget_float = CreateFloatOrDoubleEquivalentOfArrayGet(aget_int);
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}
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// Replace the original int/long instruction. Note that it may have phi
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// uses, environment uses, as well as real uses (from untyped ArraySets).
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// We need to re-run primitive type propagation on its dependent instructions.
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aget_int->ReplaceWith(aget_float);
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aget_int->GetBlock()->RemoveInstruction(aget_int);
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AddDependentInstructionsToWorklist(aget_float, &worklist);
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}
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}
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// Set a flag stating that types of ArrayGets have been resolved. Requesting
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// equivalent of the wrong type with GetFloatOrDoubleEquivalentOfArrayGet
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// will fail from now on.
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agets_fixed_ = true;
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for (HArraySet* aset : ambiguous_asets_) {
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HInstruction* array = aset->GetArray();
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if (!array->GetReferenceTypeInfo().IsPrimitiveArrayClass()) {
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// RTP did not type the input array. Bail.
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return false;
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}
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HInstruction* value = aset->GetValue();
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Primitive::Type value_type = value->GetType();
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Primitive::Type array_type = GetPrimitiveArrayComponentType(array);
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DCHECK_EQ(Primitive::Is64BitType(value_type), Primitive::Is64BitType(array_type));
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if (Primitive::IsFloatingPointType(array_type)) {
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if (!Primitive::IsFloatingPointType(value_type)) {
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DCHECK(Primitive::IsIntegralType(value_type));
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// Array elements are floating-point but the value has not been replaced
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// with its floating-point equivalent. The replacement must always
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// succeed in code validated by the verifier.
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HInstruction* equivalent = GetFloatOrDoubleEquivalent(value, array_type);
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DCHECK(equivalent != nullptr);
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aset->ReplaceInput(equivalent, /* input_index */ 2);
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if (equivalent->IsPhi()) {
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// Returned equivalent is a phi which may not have had its inputs
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// replaced yet. We need to run primitive type propagation on it.
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worklist.push_back(equivalent->AsPhi());
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}
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}
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// Refine the side effects of this floating point aset. Note that we do this even if
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// no replacement occurs, since the right-hand-side may have been corrected already.
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aset->ComputeSideEffects();
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} else {
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// Array elements are integral and the value assigned to it initially
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// was integral too. Nothing to do.
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DCHECK(Primitive::IsIntegralType(array_type));
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DCHECK(Primitive::IsIntegralType(value_type));
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}
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}
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}
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if (!worklist.empty()) {
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ProcessPrimitiveTypePropagationWorklist(&worklist);
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EquivalentPhisCleanup();
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}
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return true;
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}
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static bool HasAliasInEnvironments(HInstruction* instruction) {
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HEnvironment* last_user = nullptr;
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for (const HUseListNode<HEnvironment*>& use : instruction->GetEnvUses()) {
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DCHECK(use.GetUser() != nullptr);
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// Note: The first comparison (== null) always fails.
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if (use.GetUser() == last_user) {
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return true;
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}
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last_user = use.GetUser();
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}
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if (kIsDebugBuild) {
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// Do a quadratic search to ensure same environment uses are next
|
||||
// to each other.
|
||||
const HUseList<HEnvironment*>& env_uses = instruction->GetEnvUses();
|
||||
for (auto current = env_uses.begin(), end = env_uses.end(); current != end; ++current) {
|
||||
auto next = current;
|
||||
for (++next; next != end; ++next) {
|
||||
DCHECK(next->GetUser() != current->GetUser());
|
||||
}
|
||||
}
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
void SsaBuilder::RemoveRedundantUninitializedStrings() {
|
||||
if (graph_->IsDebuggable()) {
|
||||
// Do not perform the optimization for consistency with the interpreter
|
||||
// which always allocates an object for new-instance of String.
|
||||
return;
|
||||
}
|
||||
|
||||
for (HNewInstance* new_instance : uninitialized_strings_) {
|
||||
DCHECK(new_instance->IsInBlock());
|
||||
DCHECK(new_instance->IsStringAlloc());
|
||||
|
||||
// Replace NewInstance of String with NullConstant if not used prior to
|
||||
// calling StringFactory. In case of deoptimization, the interpreter is
|
||||
// expected to skip null check on the `this` argument of the StringFactory call.
|
||||
if (!new_instance->HasNonEnvironmentUses() && !HasAliasInEnvironments(new_instance)) {
|
||||
new_instance->ReplaceWith(graph_->GetNullConstant());
|
||||
new_instance->GetBlock()->RemoveInstruction(new_instance);
|
||||
|
||||
// Remove LoadClass if not needed any more.
|
||||
HInstruction* input = new_instance->InputAt(0);
|
||||
HLoadClass* load_class = nullptr;
|
||||
|
||||
// If the class was not present in the dex cache at the point of building
|
||||
// the graph, the builder inserted a HClinitCheck in between. Since the String
|
||||
// class is always initialized at the point of running Java code, we can remove
|
||||
// that check.
|
||||
if (input->IsClinitCheck()) {
|
||||
load_class = input->InputAt(0)->AsLoadClass();
|
||||
input->ReplaceWith(load_class);
|
||||
input->GetBlock()->RemoveInstruction(input);
|
||||
} else {
|
||||
load_class = input->AsLoadClass();
|
||||
DCHECK(new_instance->IsStringAlloc());
|
||||
DCHECK(!load_class->NeedsAccessCheck()) << "String class is always accessible";
|
||||
}
|
||||
DCHECK(load_class != nullptr);
|
||||
if (!load_class->HasUses()) {
|
||||
// Even if the HLoadClass needs access check, we can remove it, as we know the
|
||||
// String class does not need it.
|
||||
load_class->GetBlock()->RemoveInstruction(load_class);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
GraphAnalysisResult SsaBuilder::BuildSsa() {
|
||||
DCHECK(!graph_->IsInSsaForm());
|
||||
|
||||
// 1) Propagate types of phis. At this point, phis are typed void in the general
|
||||
// case, or float/double/reference if we created an equivalent phi. So we need
|
||||
// to propagate the types across phis to give them a correct type. If a type
|
||||
// conflict is detected in this stage, the phi is marked dead.
|
||||
RunPrimitiveTypePropagation();
|
||||
|
||||
// 2) Now that the correct primitive types have been assigned, we can get rid
|
||||
// of redundant phis. Note that we cannot do this phase before type propagation,
|
||||
// otherwise we could get rid of phi equivalents, whose presence is a requirement
|
||||
// for the type propagation phase. Note that this is to satisfy statement (a)
|
||||
// of the SsaBuilder (see ssa_builder.h).
|
||||
SsaRedundantPhiElimination(graph_).Run();
|
||||
|
||||
// 3) Fix the type for null constants which are part of an equality comparison.
|
||||
// We need to do this after redundant phi elimination, to ensure the only cases
|
||||
// that we can see are reference comparison against 0. The redundant phi
|
||||
// elimination ensures we do not see a phi taking two 0 constants in a HEqual
|
||||
// or HNotEqual.
|
||||
FixNullConstantType();
|
||||
|
||||
// 4) Compute type of reference type instructions. The pass assumes that
|
||||
// NullConstant has been fixed up.
|
||||
ReferenceTypePropagation(graph_,
|
||||
class_loader_,
|
||||
dex_cache_,
|
||||
handles_,
|
||||
/* is_first_run */ true).Run();
|
||||
|
||||
// 5) HInstructionBuilder duplicated ArrayGet instructions with ambiguous type
|
||||
// (int/float or long/double) and marked ArraySets with ambiguous input type.
|
||||
// Now that RTP computed the type of the array input, the ambiguity can be
|
||||
// resolved and the correct equivalents kept.
|
||||
if (!FixAmbiguousArrayOps()) {
|
||||
return kAnalysisFailAmbiguousArrayOp;
|
||||
}
|
||||
|
||||
// 6) Mark dead phis. This will mark phis which are not used by instructions
|
||||
// or other live phis. If compiling as debuggable code, phis will also be kept
|
||||
// live if they have an environment use.
|
||||
SsaDeadPhiElimination dead_phi_elimimation(graph_);
|
||||
dead_phi_elimimation.MarkDeadPhis();
|
||||
|
||||
// 7) Make sure environments use the right phi equivalent: a phi marked dead
|
||||
// can have a phi equivalent that is not dead. In that case we have to replace
|
||||
// it with the live equivalent because deoptimization and try/catch rely on
|
||||
// environments containing values of all live vregs at that point. Note that
|
||||
// there can be multiple phis for the same Dex register that are live
|
||||
// (for example when merging constants), in which case it is okay for the
|
||||
// environments to just reference one.
|
||||
FixEnvironmentPhis();
|
||||
|
||||
// 8) Now that the right phis are used for the environments, we can eliminate
|
||||
// phis we do not need. Regardless of the debuggable status, this phase is
|
||||
/// necessary for statement (b) of the SsaBuilder (see ssa_builder.h), as well
|
||||
// as for the code generation, which does not deal with phis of conflicting
|
||||
// input types.
|
||||
dead_phi_elimimation.EliminateDeadPhis();
|
||||
|
||||
// 9) HInstructionBuidler replaced uses of NewInstances of String with the
|
||||
// results of their corresponding StringFactory calls. Unless the String
|
||||
// objects are used before they are initialized, they can be replaced with
|
||||
// NullConstant. Note that this optimization is valid only if unsimplified
|
||||
// code does not use the uninitialized value because we assume execution can
|
||||
// be deoptimized at any safepoint. We must therefore perform it before any
|
||||
// other optimizations.
|
||||
RemoveRedundantUninitializedStrings();
|
||||
|
||||
graph_->SetInSsaForm();
|
||||
return kAnalysisSuccess;
|
||||
}
|
||||
|
||||
/**
|
||||
* Constants in the Dex format are not typed. So the builder types them as
|
||||
* integers, but when doing the SSA form, we might realize the constant
|
||||
* is used for floating point operations. We create a floating-point equivalent
|
||||
* constant to make the operations correctly typed.
|
||||
*/
|
||||
HFloatConstant* SsaBuilder::GetFloatEquivalent(HIntConstant* constant) {
|
||||
// We place the floating point constant next to this constant.
|
||||
HFloatConstant* result = constant->GetNext()->AsFloatConstant();
|
||||
if (result == nullptr) {
|
||||
float value = bit_cast<float, int32_t>(constant->GetValue());
|
||||
result = new (graph_->GetArena()) HFloatConstant(value);
|
||||
constant->GetBlock()->InsertInstructionBefore(result, constant->GetNext());
|
||||
graph_->CacheFloatConstant(result);
|
||||
} else {
|
||||
// If there is already a constant with the expected type, we know it is
|
||||
// the floating point equivalent of this constant.
|
||||
DCHECK_EQ((bit_cast<int32_t, float>(result->GetValue())), constant->GetValue());
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
/**
|
||||
* Wide constants in the Dex format are not typed. So the builder types them as
|
||||
* longs, but when doing the SSA form, we might realize the constant
|
||||
* is used for floating point operations. We create a floating-point equivalent
|
||||
* constant to make the operations correctly typed.
|
||||
*/
|
||||
HDoubleConstant* SsaBuilder::GetDoubleEquivalent(HLongConstant* constant) {
|
||||
// We place the floating point constant next to this constant.
|
||||
HDoubleConstant* result = constant->GetNext()->AsDoubleConstant();
|
||||
if (result == nullptr) {
|
||||
double value = bit_cast<double, int64_t>(constant->GetValue());
|
||||
result = new (graph_->GetArena()) HDoubleConstant(value);
|
||||
constant->GetBlock()->InsertInstructionBefore(result, constant->GetNext());
|
||||
graph_->CacheDoubleConstant(result);
|
||||
} else {
|
||||
// If there is already a constant with the expected type, we know it is
|
||||
// the floating point equivalent of this constant.
|
||||
DCHECK_EQ((bit_cast<int64_t, double>(result->GetValue())), constant->GetValue());
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
/**
|
||||
* Because of Dex format, we might end up having the same phi being
|
||||
* used for non floating point operations and floating point / reference operations.
|
||||
* Because we want the graph to be correctly typed (and thereafter avoid moves between
|
||||
* floating point registers and core registers), we need to create a copy of the
|
||||
* phi with a floating point / reference type.
|
||||
*/
|
||||
HPhi* SsaBuilder::GetFloatDoubleOrReferenceEquivalentOfPhi(HPhi* phi, Primitive::Type type) {
|
||||
DCHECK(phi->IsLive()) << "Cannot get equivalent of a dead phi since it would create a live one.";
|
||||
|
||||
// We place the floating point /reference phi next to this phi.
|
||||
HInstruction* next = phi->GetNext();
|
||||
if (next != nullptr
|
||||
&& next->AsPhi()->GetRegNumber() == phi->GetRegNumber()
|
||||
&& next->GetType() != type) {
|
||||
// Move to the next phi to see if it is the one we are looking for.
|
||||
next = next->GetNext();
|
||||
}
|
||||
|
||||
if (next == nullptr
|
||||
|| (next->AsPhi()->GetRegNumber() != phi->GetRegNumber())
|
||||
|| (next->GetType() != type)) {
|
||||
ArenaAllocator* allocator = graph_->GetArena();
|
||||
HInputsRef inputs = phi->GetInputs();
|
||||
HPhi* new_phi =
|
||||
new (allocator) HPhi(allocator, phi->GetRegNumber(), inputs.size(), type);
|
||||
// Copy the inputs. Note that the graph may not be correctly typed
|
||||
// by doing this copy, but the type propagation phase will fix it.
|
||||
ArrayRef<HUserRecord<HInstruction*>> new_input_records = new_phi->GetInputRecords();
|
||||
for (size_t i = 0; i < inputs.size(); ++i) {
|
||||
new_input_records[i] = HUserRecord<HInstruction*>(inputs[i]);
|
||||
}
|
||||
phi->GetBlock()->InsertPhiAfter(new_phi, phi);
|
||||
DCHECK(new_phi->IsLive());
|
||||
return new_phi;
|
||||
} else {
|
||||
// An existing equivalent was found. If it is dead, conflict was previously
|
||||
// identified and we return nullptr instead.
|
||||
HPhi* next_phi = next->AsPhi();
|
||||
DCHECK_EQ(next_phi->GetType(), type);
|
||||
return next_phi->IsLive() ? next_phi : nullptr;
|
||||
}
|
||||
}
|
||||
|
||||
HArrayGet* SsaBuilder::GetFloatOrDoubleEquivalentOfArrayGet(HArrayGet* aget) {
|
||||
DCHECK(Primitive::IsIntegralType(aget->GetType()));
|
||||
|
||||
if (!Primitive::IsIntOrLongType(aget->GetType())) {
|
||||
// Cannot type boolean, char, byte, short to float/double.
|
||||
return nullptr;
|
||||
}
|
||||
|
||||
DCHECK(ContainsElement(ambiguous_agets_, aget));
|
||||
if (agets_fixed_) {
|
||||
// This used to be an ambiguous ArrayGet but its type has been resolved to
|
||||
// int/long. Requesting a float/double equivalent should lead to a conflict.
|
||||
if (kIsDebugBuild) {
|
||||
ScopedObjectAccess soa(Thread::Current());
|
||||
DCHECK(Primitive::IsIntOrLongType(GetPrimitiveArrayComponentType(aget->GetArray())));
|
||||
}
|
||||
return nullptr;
|
||||
} else {
|
||||
// This is an ambiguous ArrayGet which has not been resolved yet. Return an
|
||||
// equivalent float/double instruction to use until it is resolved.
|
||||
HArrayGet* equivalent = FindFloatOrDoubleEquivalentOfArrayGet(aget);
|
||||
return (equivalent == nullptr) ? CreateFloatOrDoubleEquivalentOfArrayGet(aget) : equivalent;
|
||||
}
|
||||
}
|
||||
|
||||
HInstruction* SsaBuilder::GetFloatOrDoubleEquivalent(HInstruction* value, Primitive::Type type) {
|
||||
if (value->IsArrayGet()) {
|
||||
return GetFloatOrDoubleEquivalentOfArrayGet(value->AsArrayGet());
|
||||
} else if (value->IsLongConstant()) {
|
||||
return GetDoubleEquivalent(value->AsLongConstant());
|
||||
} else if (value->IsIntConstant()) {
|
||||
return GetFloatEquivalent(value->AsIntConstant());
|
||||
} else if (value->IsPhi()) {
|
||||
return GetFloatDoubleOrReferenceEquivalentOfPhi(value->AsPhi(), type);
|
||||
} else {
|
||||
return nullptr;
|
||||
}
|
||||
}
|
||||
|
||||
HInstruction* SsaBuilder::GetReferenceTypeEquivalent(HInstruction* value) {
|
||||
if (value->IsIntConstant() && value->AsIntConstant()->GetValue() == 0) {
|
||||
return graph_->GetNullConstant();
|
||||
} else if (value->IsPhi()) {
|
||||
return GetFloatDoubleOrReferenceEquivalentOfPhi(value->AsPhi(), Primitive::kPrimNot);
|
||||
} else {
|
||||
return nullptr;
|
||||
}
|
||||
}
|
||||
|
||||
} // namespace art
|
Loading…
Add table
Add a link
Reference in a new issue