/*
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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 "pc_relative_fixups_x86.h"
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#include "code_generator_x86.h"
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#include "intrinsics_x86.h"
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namespace art {
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namespace x86 {
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/**
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* Finds instructions that need the constant area base as an input.
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*/
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class PCRelativeHandlerVisitor : public HGraphVisitor {
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public:
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PCRelativeHandlerVisitor(HGraph* graph, CodeGenerator* codegen)
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: HGraphVisitor(graph),
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codegen_(down_cast<CodeGeneratorX86*>(codegen)),
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base_(nullptr) {}
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void MoveBaseIfNeeded() {
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if (base_ != nullptr) {
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// Bring the base closer to the first use (previously, it was in the
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// entry block) and relieve some pressure on the register allocator
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// while avoiding recalculation of the base in a loop.
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base_->MoveBeforeFirstUserAndOutOfLoops();
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}
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}
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private:
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void VisitAdd(HAdd* add) override {
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BinaryFP(add);
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}
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void VisitSub(HSub* sub) override {
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BinaryFP(sub);
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}
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void VisitMul(HMul* mul) override {
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BinaryFP(mul);
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}
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void VisitDiv(HDiv* div) override {
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BinaryFP(div);
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}
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void VisitCompare(HCompare* compare) override {
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BinaryFP(compare);
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}
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void VisitReturn(HReturn* ret) override {
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HConstant* value = ret->InputAt(0)->AsConstant();
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if ((value != nullptr && DataType::IsFloatingPointType(value->GetType()))) {
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ReplaceInput(ret, value, 0, true);
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}
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}
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void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) override {
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HandleInvoke(invoke);
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}
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void VisitInvokeVirtual(HInvokeVirtual* invoke) override {
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HandleInvoke(invoke);
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}
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void VisitInvokeInterface(HInvokeInterface* invoke) override {
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HandleInvoke(invoke);
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}
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void VisitLoadClass(HLoadClass* load_class) override {
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if (load_class->HasPcRelativeLoadKind()) {
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HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(load_class);
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load_class->AddSpecialInput(method_address);
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}
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}
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void VisitLoadString(HLoadString* load_string) override {
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if (load_string->HasPcRelativeLoadKind()) {
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HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(load_string);
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load_string->AddSpecialInput(method_address);
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}
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}
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void BinaryFP(HBinaryOperation* bin) {
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HConstant* rhs = bin->InputAt(1)->AsConstant();
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if (rhs != nullptr && DataType::IsFloatingPointType(rhs->GetType())) {
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ReplaceInput(bin, rhs, 1, false);
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}
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}
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void VisitEqual(HEqual* cond) override {
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BinaryFP(cond);
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}
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void VisitNotEqual(HNotEqual* cond) override {
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BinaryFP(cond);
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}
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void VisitLessThan(HLessThan* cond) override {
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BinaryFP(cond);
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}
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void VisitLessThanOrEqual(HLessThanOrEqual* cond) override {
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BinaryFP(cond);
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}
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void VisitGreaterThan(HGreaterThan* cond) override {
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BinaryFP(cond);
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}
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void VisitGreaterThanOrEqual(HGreaterThanOrEqual* cond) override {
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BinaryFP(cond);
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}
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void VisitNeg(HNeg* neg) override {
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if (DataType::IsFloatingPointType(neg->GetType())) {
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// We need to replace the HNeg with a HX86FPNeg in order to address the constant area.
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HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(neg);
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HGraph* graph = GetGraph();
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HBasicBlock* block = neg->GetBlock();
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HX86FPNeg* x86_fp_neg = new (graph->GetAllocator()) HX86FPNeg(
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neg->GetType(),
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neg->InputAt(0),
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method_address,
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neg->GetDexPc());
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block->ReplaceAndRemoveInstructionWith(neg, x86_fp_neg);
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}
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}
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void VisitPackedSwitch(HPackedSwitch* switch_insn) override {
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if (switch_insn->GetNumEntries() <=
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InstructionCodeGeneratorX86::kPackedSwitchJumpTableThreshold) {
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return;
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}
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// We need to replace the HPackedSwitch with a HX86PackedSwitch in order to
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// address the constant area.
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HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(switch_insn);
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HGraph* graph = GetGraph();
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HBasicBlock* block = switch_insn->GetBlock();
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HX86PackedSwitch* x86_switch = new (graph->GetAllocator()) HX86PackedSwitch(
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switch_insn->GetStartValue(),
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switch_insn->GetNumEntries(),
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switch_insn->InputAt(0),
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method_address,
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switch_insn->GetDexPc());
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block->ReplaceAndRemoveInstructionWith(switch_insn, x86_switch);
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}
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HX86ComputeBaseMethodAddress* GetPCRelativeBasePointer(HInstruction* cursor) {
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bool has_irreducible_loops = GetGraph()->HasIrreducibleLoops();
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if (!has_irreducible_loops) {
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// Ensure we only initialize the pointer once.
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if (base_ != nullptr) {
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return base_;
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}
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}
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// Insert the base at the start of the entry block, move it to a better
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// position later in MoveBaseIfNeeded().
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HX86ComputeBaseMethodAddress* method_address =
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new (GetGraph()->GetAllocator()) HX86ComputeBaseMethodAddress();
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if (has_irreducible_loops) {
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cursor->GetBlock()->InsertInstructionBefore(method_address, cursor);
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} else {
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HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
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entry_block->InsertInstructionBefore(method_address, entry_block->GetFirstInstruction());
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base_ = method_address;
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}
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return method_address;
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}
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void ReplaceInput(HInstruction* insn, HConstant* value, int input_index, bool materialize) {
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HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(insn);
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HX86LoadFromConstantTable* load_constant =
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new (GetGraph()->GetAllocator()) HX86LoadFromConstantTable(method_address, value);
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if (!materialize) {
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load_constant->MarkEmittedAtUseSite();
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}
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insn->GetBlock()->InsertInstructionBefore(load_constant, insn);
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insn->ReplaceInput(load_constant, input_index);
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}
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void HandleInvoke(HInvoke* invoke) {
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HInvokeStaticOrDirect* invoke_static_or_direct = invoke->AsInvokeStaticOrDirect();
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// We can't add the method address if we already have a current method pointer.
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// This may arise when sharpening doesn't remove the current method pointer from the invoke.
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if (invoke_static_or_direct != nullptr && invoke_static_or_direct->HasCurrentMethodInput()) {
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// Note: This happens only for recursive calls (including compiling an intrinsic
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// by faking a call to itself; we use kRuntimeCall for this case).
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DCHECK(!invoke_static_or_direct->HasPcRelativeMethodLoadKind());
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return;
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}
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// If this is an invoke-static/-direct with PC-relative addressing (within boot image
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// or using .bss or .data.bimg.rel.ro), we need the PC-relative address base.
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bool base_added = false;
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if (invoke_static_or_direct != nullptr &&
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invoke_static_or_direct->HasPcRelativeMethodLoadKind() &&
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!IsCallFreeIntrinsic<IntrinsicLocationsBuilderX86>(invoke, codegen_)) {
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HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(invoke);
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// Add the extra parameter.
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invoke_static_or_direct->AddSpecialInput(method_address);
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base_added = true;
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}
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// Ensure that we can load FP arguments from the constant area.
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HInputsRef inputs = invoke->GetInputs();
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for (size_t i = 0; i < inputs.size(); i++) {
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HConstant* input = inputs[i]->AsConstant();
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if (input != nullptr && DataType::IsFloatingPointType(input->GetType())) {
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ReplaceInput(invoke, input, i, true);
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}
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}
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switch (invoke->GetIntrinsic()) {
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case Intrinsics::kIntegerValueOf:
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// This intrinsic can be call free if it loads the address of the boot image object.
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// If we're compiling PIC, we need the address base for loading from .data.bimg.rel.ro.
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if (!codegen_->GetCompilerOptions().GetCompilePic()) {
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break;
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}
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FALLTHROUGH_INTENDED;
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case Intrinsics::kMathRoundFloat:
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// This intrinsic needs the constant area.
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if (!base_added) {
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DCHECK(invoke_static_or_direct != nullptr);
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DCHECK(!invoke_static_or_direct->HasCurrentMethodInput());
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HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(invoke);
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invoke_static_or_direct->AddSpecialInput(method_address);
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}
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break;
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default:
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break;
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}
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}
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CodeGeneratorX86* codegen_;
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// The generated HX86ComputeBaseMethodAddress in the entry block needed as an
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// input to the HX86LoadFromConstantTable instructions. Only set for
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// graphs with reducible loops.
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HX86ComputeBaseMethodAddress* base_;
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};
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bool PcRelativeFixups::Run() {
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PCRelativeHandlerVisitor visitor(graph_, codegen_);
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visitor.VisitInsertionOrder();
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visitor.MoveBaseIfNeeded();
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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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