compiler/optimizing/pc_relative_fixups_x86.cc - platform/art - Git at Google

 /*
  * 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 && Primitive::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 VisitLoadString(HLoadString* load_string) OVERRIDE {
     HLoadString::LoadKind load_kind = load_string->GetLoadKind();
     if (load_kind == HLoadString::LoadKind::kBootImageLinkTimePcRelative ||
         load_kind == HLoadString::LoadKind::kDexCachePcRelative) {
       InitializePCRelativeBasePointer();
       load_string->AddSpecialInput(base_);
     }
   }

   void BinaryFP(HBinaryOperation* bin) {
     HConstant* rhs = bin->InputAt(1)->AsConstant();
     if (rhs != nullptr && Primitive::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 (Primitive::IsFloatingPointType(neg->GetType())) {
       // We need to replace the HNeg with a HX86FPNeg in order to address the constant area.
       InitializePCRelativeBasePointer();
       HGraph* graph = GetGraph();
       HBasicBlock* block = neg->GetBlock();
       HX86FPNeg* x86_fp_neg = new (graph->GetArena()) HX86FPNeg(
           neg->GetType(),
           neg->InputAt(0),
           base_,
           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.
     InitializePCRelativeBasePointer();
     HGraph* graph = GetGraph();
     HBasicBlock* block = switch_insn->GetBlock();
     HX86PackedSwitch* x86_switch = new (graph->GetArena()) HX86PackedSwitch(
         switch_insn->GetStartValue(),
         switch_insn->GetNumEntries(),
         switch_insn->InputAt(0),
         base_,
         switch_insn->GetDexPc());
     block->ReplaceAndRemoveInstructionWith(switch_insn, x86_switch);
   }

   void InitializePCRelativeBasePointer() {
     // Ensure we only initialize the pointer once.
     if (base_ != nullptr) {
       return;
     }
     // Insert the base at the start of the entry block, move it to a better
     // position later in MoveBaseIfNeeded().
     base_ = new (GetGraph()->GetArena()) HX86ComputeBaseMethodAddress();
     HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
     entry_block->InsertInstructionBefore(base_, entry_block->GetFirstInstruction());
     DCHECK(base_ != nullptr);
   }

   void ReplaceInput(HInstruction* insn, HConstant* value, int input_index, bool materialize) {
     InitializePCRelativeBasePointer();
     HX86LoadFromConstantTable* load_constant =
         new (GetGraph()->GetArena()) HX86LoadFromConstantTable(base_, value);
     if (!materialize) {
       load_constant->MarkEmittedAtUseSite();
     }
     insn->GetBlock()->InsertInstructionBefore(load_constant, insn);
     insn->ReplaceInput(load_constant, input_index);
   }

   void HandleInvoke(HInvoke* invoke) {
     // If this is an invoke-static/-direct with PC-relative dex cache array
     // addressing, we need the PC-relative address base.
     HInvokeStaticOrDirect* invoke_static_or_direct = invoke->AsInvokeStaticOrDirect();
     // We can't add a pointer to the constant area 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()) {
       DCHECK(!invoke_static_or_direct->HasPcRelativeDexCache());
       return;
     }

     bool base_added = false;
     if (invoke_static_or_direct != nullptr &&
         invoke_static_or_direct->HasPcRelativeDexCache() &&
         !WillHaveCallFreeIntrinsicsCodeGen(invoke)) {
       InitializePCRelativeBasePointer();
       // Add the extra parameter base_.
       invoke_static_or_direct->AddSpecialInput(base_);
       base_added = true;
     }

     // Ensure that we can load FP arguments from the constant area.
     for (size_t i = 0, e = invoke->InputCount(); i < e; i++) {
       HConstant* input = invoke->InputAt(i)->AsConstant();
       if (input != nullptr && Primitive::IsFloatingPointType(input->GetType())) {
         ReplaceInput(invoke, input, i, true);
       }
     }

     // These intrinsics need the constant area.
     switch (invoke->GetIntrinsic()) {
       case Intrinsics::kMathAbsDouble:
       case Intrinsics::kMathAbsFloat:
       case Intrinsics::kMathMaxDoubleDouble:
       case Intrinsics::kMathMaxFloatFloat:
       case Intrinsics::kMathMinDoubleDouble:
       case Intrinsics::kMathMinFloatFloat:
         if (!base_added) {
           DCHECK(invoke_static_or_direct != nullptr);
           DCHECK(!invoke_static_or_direct->HasCurrentMethodInput());
           InitializePCRelativeBasePointer();
           invoke_static_or_direct->AddSpecialInput(base_);
         }
         break;
       default:
         break;
     }
   }

   bool WillHaveCallFreeIntrinsicsCodeGen(HInvoke* invoke) {
     if (invoke->GetIntrinsic() != Intrinsics::kNone) {
       // This invoke may have intrinsic code generation defined. However, we must
       // now also determine if this code generation is truly there and call-free
       // (not unimplemented, no bail on instruction features, or call on slow path).
       // This is done by actually calling the locations builder on the instruction
       // and clearing out the locations once result is known. We assume this
       // call only has creating locations as side effects!
       IntrinsicLocationsBuilderX86 builder(codegen_);
       bool success = builder.TryDispatch(invoke) && !invoke->GetLocations()->CanCall();
       invoke->SetLocations(nullptr);
       return success;
     }
     return false;
   }

   CodeGeneratorX86* codegen_;

   // The generated HX86ComputeBaseMethodAddress in the entry block needed as an
   // input to the HX86LoadFromConstantTable instructions.
   HX86ComputeBaseMethodAddress* base_;
 };

 void PcRelativeFixups::Run() {
   if (graph_->HasIrreducibleLoops()) {
     // Do not run this optimization, as irreducible loops do not work with an instruction
     // that can be live-in at the irreducible loop header.
     return;
   }
   PCRelativeHandlerVisitor visitor(graph_, codegen_);
   visitor.VisitInsertionOrder();
   visitor.MoveBaseIfNeeded();
 }

 }  // namespace x86
 }  // namespace art
	/*
	* 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 && Primitive::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 VisitLoadString(HLoadString* load_string) OVERRIDE {
	HLoadString::LoadKind load_kind = load_string->GetLoadKind();
	if (load_kind == HLoadString::LoadKind::kBootImageLinkTimePcRelative \|\|
	load_kind == HLoadString::LoadKind::kDexCachePcRelative) {
	InitializePCRelativeBasePointer();
	load_string->AddSpecialInput(base_);
	}
	}

	void BinaryFP(HBinaryOperation* bin) {
	HConstant* rhs = bin->InputAt(1)->AsConstant();
	if (rhs != nullptr && Primitive::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 (Primitive::IsFloatingPointType(neg->GetType())) {
	// We need to replace the HNeg with a HX86FPNeg in order to address the constant area.
	InitializePCRelativeBasePointer();
	HGraph* graph = GetGraph();
	HBasicBlock* block = neg->GetBlock();
	HX86FPNeg* x86_fp_neg = new (graph->GetArena()) HX86FPNeg(
	neg->GetType(),
	neg->InputAt(0),
	base_,
	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.
	InitializePCRelativeBasePointer();
	HGraph* graph = GetGraph();
	HBasicBlock* block = switch_insn->GetBlock();
	HX86PackedSwitch* x86_switch = new (graph->GetArena()) HX86PackedSwitch(
	switch_insn->GetStartValue(),
	switch_insn->GetNumEntries(),
	switch_insn->InputAt(0),
	base_,
	switch_insn->GetDexPc());
	block->ReplaceAndRemoveInstructionWith(switch_insn, x86_switch);
	}

	void InitializePCRelativeBasePointer() {
	// Ensure we only initialize the pointer once.
	if (base_ != nullptr) {
	return;
	}
	// Insert the base at the start of the entry block, move it to a better
	// position later in MoveBaseIfNeeded().
	base_ = new (GetGraph()->GetArena()) HX86ComputeBaseMethodAddress();
	HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
	entry_block->InsertInstructionBefore(base_, entry_block->GetFirstInstruction());
	DCHECK(base_ != nullptr);
	}

	void ReplaceInput(HInstruction* insn, HConstant* value, int input_index, bool materialize) {
	InitializePCRelativeBasePointer();
	HX86LoadFromConstantTable* load_constant =
	new (GetGraph()->GetArena()) HX86LoadFromConstantTable(base_, value);
	if (!materialize) {
	load_constant->MarkEmittedAtUseSite();
	}
	insn->GetBlock()->InsertInstructionBefore(load_constant, insn);
	insn->ReplaceInput(load_constant, input_index);
	}

	void HandleInvoke(HInvoke* invoke) {
	// If this is an invoke-static/-direct with PC-relative dex cache array
	// addressing, we need the PC-relative address base.
	HInvokeStaticOrDirect* invoke_static_or_direct = invoke->AsInvokeStaticOrDirect();
	// We can't add a pointer to the constant area 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()) {
	DCHECK(!invoke_static_or_direct->HasPcRelativeDexCache());
	return;
	}

	bool base_added = false;
	if (invoke_static_or_direct != nullptr &&
	invoke_static_or_direct->HasPcRelativeDexCache() &&
	!WillHaveCallFreeIntrinsicsCodeGen(invoke)) {
	InitializePCRelativeBasePointer();
	// Add the extra parameter base_.
	invoke_static_or_direct->AddSpecialInput(base_);
	base_added = true;
	}

	// Ensure that we can load FP arguments from the constant area.
	for (size_t i = 0, e = invoke->InputCount(); i < e; i++) {
	HConstant* input = invoke->InputAt(i)->AsConstant();
	if (input != nullptr && Primitive::IsFloatingPointType(input->GetType())) {
	ReplaceInput(invoke, input, i, true);
	}
	}

	// These intrinsics need the constant area.
	switch (invoke->GetIntrinsic()) {
	case Intrinsics::kMathAbsDouble:
	case Intrinsics::kMathAbsFloat:
	case Intrinsics::kMathMaxDoubleDouble:
	case Intrinsics::kMathMaxFloatFloat:
	case Intrinsics::kMathMinDoubleDouble:
	case Intrinsics::kMathMinFloatFloat:
	if (!base_added) {
	DCHECK(invoke_static_or_direct != nullptr);
	DCHECK(!invoke_static_or_direct->HasCurrentMethodInput());
	InitializePCRelativeBasePointer();
	invoke_static_or_direct->AddSpecialInput(base_);
	}
	break;
	default:
	break;
	}
	}

	bool WillHaveCallFreeIntrinsicsCodeGen(HInvoke* invoke) {
	if (invoke->GetIntrinsic() != Intrinsics::kNone) {
	// This invoke may have intrinsic code generation defined. However, we must
	// now also determine if this code generation is truly there and call-free
	// (not unimplemented, no bail on instruction features, or call on slow path).
	// This is done by actually calling the locations builder on the instruction
	// and clearing out the locations once result is known. We assume this
	// call only has creating locations as side effects!
	IntrinsicLocationsBuilderX86 builder(codegen_);
	bool success = builder.TryDispatch(invoke) && !invoke->GetLocations()->CanCall();
	invoke->SetLocations(nullptr);
	return success;
	}
	return false;
	}

	CodeGeneratorX86* codegen_;

	// The generated HX86ComputeBaseMethodAddress in the entry block needed as an
	// input to the HX86LoadFromConstantTable instructions.
	HX86ComputeBaseMethodAddress* base_;
	};

	void PcRelativeFixups::Run() {
	if (graph_->HasIrreducibleLoops()) {
	// Do not run this optimization, as irreducible loops do not work with an instruction
	// that can be live-in at the irreducible loop header.
	return;
	}
	PCRelativeHandlerVisitor visitor(graph_, codegen_);
	visitor.VisitInsertionOrder();
	visitor.MoveBaseIfNeeded();
	}

	} // namespace x86
	} // namespace art