/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "pc_relative_fixups_x86.h"
#include "code_generator_x86.h"
#include "intrinsics_x86.h"
namespace art {
namespace x86 {
/**
* Finds instructions that need the constant area base as an input.
*/
class PCRelativeHandlerVisitor : public HGraphVisitor {
public:
PCRelativeHandlerVisitor(HGraph* graph, CodeGenerator* codegen)
: HGraphVisitor(graph),
codegen_(down_cast<CodeGeneratorX86*>(codegen)),
base_(nullptr) {}
void MoveBaseIfNeeded() {
if (base_ != nullptr) {
// Bring the base closer to the first use (previously, it was in the
// entry block) and relieve some pressure on the register allocator
// while avoiding recalculation of the base in a loop.
base_->MoveBeforeFirstUserAndOutOfLoops();
}
}
private:
void VisitAdd(HAdd* add) override {
BinaryFP(add);
}
void VisitSub(HSub* sub) override {
BinaryFP(sub);
}
void VisitMul(HMul* mul) override {
BinaryFP(mul);
}
void VisitDiv(HDiv* div) override {
BinaryFP(div);
}
void VisitCompare(HCompare* compare) override {
BinaryFP(compare);
}
void VisitReturn(HReturn* ret) override {
HConstant* value = ret->InputAt(0)->AsConstant();
if ((value != nullptr && DataType::IsFloatingPointType(value->GetType()))) {
ReplaceInput(ret, value, 0, true);
}
}
void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) override {
HandleInvoke(invoke);
}
void VisitInvokeVirtual(HInvokeVirtual* invoke) override {
HandleInvoke(invoke);
}
void VisitInvokeInterface(HInvokeInterface* invoke) override {
HandleInvoke(invoke);
}
void VisitLoadClass(HLoadClass* load_class) override {
if (load_class->HasPcRelativeLoadKind()) {
HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(load_class);
load_class->AddSpecialInput(method_address);
}
}
void VisitLoadString(HLoadString* load_string) override {
if (load_string->HasPcRelativeLoadKind()) {
HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(load_string);
load_string->AddSpecialInput(method_address);
}
}
void BinaryFP(HBinaryOperation* bin) {
HConstant* rhs = bin->InputAt(1)->AsConstant();
if (rhs != nullptr && DataType::IsFloatingPointType(rhs->GetType())) {
ReplaceInput(bin, rhs, 1, false);
}
}
void VisitEqual(HEqual* cond) override {
BinaryFP(cond);
}
void VisitNotEqual(HNotEqual* cond) override {
BinaryFP(cond);
}
void VisitLessThan(HLessThan* cond) override {
BinaryFP(cond);
}
void VisitLessThanOrEqual(HLessThanOrEqual* cond) override {
BinaryFP(cond);
}
void VisitGreaterThan(HGreaterThan* cond) override {
BinaryFP(cond);
}
void VisitGreaterThanOrEqual(HGreaterThanOrEqual* cond) override {
BinaryFP(cond);
}
void VisitNeg(HNeg* neg) override {
if (DataType::IsFloatingPointType(neg->GetType())) {
// We need to replace the HNeg with a HX86FPNeg in order to address the constant area.
HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(neg);
HGraph* graph = GetGraph();
HBasicBlock* block = neg->GetBlock();
HX86FPNeg* x86_fp_neg = new (graph->GetAllocator()) HX86FPNeg(
neg->GetType(),
neg->InputAt(0),
method_address,
neg->GetDexPc());
block->ReplaceAndRemoveInstructionWith(neg, x86_fp_neg);
}
}
void VisitPackedSwitch(HPackedSwitch* switch_insn) override {
if (switch_insn->GetNumEntries() <=
InstructionCodeGeneratorX86::kPackedSwitchJumpTableThreshold) {
return;
}
// We need to replace the HPackedSwitch with a HX86PackedSwitch in order to
// address the constant area.
HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(switch_insn);
HGraph* graph = GetGraph();
HBasicBlock* block = switch_insn->GetBlock();
HX86PackedSwitch* x86_switch = new (graph->GetAllocator()) HX86PackedSwitch(
switch_insn->GetStartValue(),
switch_insn->GetNumEntries(),
switch_insn->InputAt(0),
method_address,
switch_insn->GetDexPc());
block->ReplaceAndRemoveInstructionWith(switch_insn, x86_switch);
}
HX86ComputeBaseMethodAddress* GetPCRelativeBasePointer(HInstruction* cursor) {
bool has_irreducible_loops = GetGraph()->HasIrreducibleLoops();
if (!has_irreducible_loops) {
// Ensure we only initialize the pointer once.
if (base_ != nullptr) {
return base_;
}
}
// Insert the base at the start of the entry block, move it to a better
// position later in MoveBaseIfNeeded().
HX86ComputeBaseMethodAddress* method_address =
new (GetGraph()->GetAllocator()) HX86ComputeBaseMethodAddress();
if (has_irreducible_loops) {
cursor->GetBlock()->InsertInstructionBefore(method_address, cursor);
} else {
HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
entry_block->InsertInstructionBefore(method_address, entry_block->GetFirstInstruction());
base_ = method_address;
}
return method_address;
}
void ReplaceInput(HInstruction* insn, HConstant* value, int input_index, bool materialize) {
HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(insn);
HX86LoadFromConstantTable* load_constant =
new (GetGraph()->GetAllocator()) HX86LoadFromConstantTable(method_address, value);
if (!materialize) {
load_constant->MarkEmittedAtUseSite();
}
insn->GetBlock()->InsertInstructionBefore(load_constant, insn);
insn->ReplaceInput(load_constant, input_index);
}
void HandleInvoke(HInvoke* invoke) {
HInvokeStaticOrDirect* invoke_static_or_direct = invoke->AsInvokeStaticOrDirect();
// We can't add the method address if we already have a current method pointer.
// This may arise when sharpening doesn't remove the current method pointer from the invoke.
if (invoke_static_or_direct != nullptr && invoke_static_or_direct->HasCurrentMethodInput()) {
// Note: This happens only for recursive calls (including compiling an intrinsic
// by faking a call to itself; we use kRuntimeCall for this case).
DCHECK(!invoke_static_or_direct->HasPcRelativeMethodLoadKind());
return;
}
// If this is an invoke-static/-direct with PC-relative addressing (within boot image
// or using .bss or .data.bimg.rel.ro), we need the PC-relative address base.
bool base_added = false;
if (invoke_static_or_direct != nullptr &&
invoke_static_or_direct->HasPcRelativeMethodLoadKind() &&
!IsCallFreeIntrinsic<IntrinsicLocationsBuilderX86>(invoke, codegen_)) {
HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(invoke);
// Add the extra parameter.
invoke_static_or_direct->AddSpecialInput(method_address);
base_added = true;
}
// Ensure that we can load FP arguments from the constant area.
HInputsRef inputs = invoke->GetInputs();
for (size_t i = 0; i < inputs.size(); i++) {
HConstant* input = inputs[i]->AsConstant();
if (input != nullptr && DataType::IsFloatingPointType(input->GetType())) {
ReplaceInput(invoke, input, i, true);
}
}
switch (invoke->GetIntrinsic()) {
case Intrinsics::kIntegerValueOf:
// This intrinsic can be call free if it loads the address of the boot image object.
// If we're compiling PIC, we need the address base for loading from .data.bimg.rel.ro.
if (!codegen_->GetCompilerOptions().GetCompilePic()) {
break;
}
FALLTHROUGH_INTENDED;
case Intrinsics::kMathRoundFloat:
// This intrinsic needs the constant area.
if (!base_added) {
DCHECK(invoke_static_or_direct != nullptr);
DCHECK(!invoke_static_or_direct->HasCurrentMethodInput());
HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(invoke);
invoke_static_or_direct->AddSpecialInput(method_address);
}
break;
default:
break;
}
}
CodeGeneratorX86* codegen_;
// The generated HX86ComputeBaseMethodAddress in the entry block needed as an
// input to the HX86LoadFromConstantTable instructions. Only set for
// graphs with reducible loops.
HX86ComputeBaseMethodAddress* base_;
};
bool PcRelativeFixups::Run() {
PCRelativeHandlerVisitor visitor(graph_, codegen_);
visitor.VisitInsertionOrder();
visitor.MoveBaseIfNeeded();
return true;
}
} // namespace x86
} // namespace art