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SparcV9StackSlots.cpp

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00001 //===- SparcV9StackSlots.cpp - Add empty stack slots to functions ---------===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This pass adds 2 empty slots at the top of function stack.  These two slots
00011 // are later used during code reoptimization for spilling the register values
00012 // when rewriting branches.
00013 //
00014 //===----------------------------------------------------------------------===//
00015 
00016 #include "SparcV9Internals.h"
00017 #include "llvm/Constant.h"
00018 #include "llvm/DerivedTypes.h"
00019 #include "llvm/Function.h"
00020 #include "llvm/CodeGen/MachineFunctionPass.h"
00021 #include "MachineFunctionInfo.h"
00022 using namespace llvm;
00023 
00024 namespace {
00025   class StackSlots : public MachineFunctionPass {
00026     const TargetMachine &Target;
00027   public:
00028     StackSlots(const TargetMachine &T) : Target(T) {}
00029     
00030     const char *getPassName() const {
00031       return "Stack Slot Insertion for profiling code";
00032     }
00033     
00034     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
00035       AU.setPreservesCFG();
00036     }
00037     
00038     bool runOnMachineFunction(MachineFunction &MF) {
00039       const Type *PtrInt = PointerType::get(Type::IntTy);
00040       unsigned Size = Target.getTargetData().getTypeSize(PtrInt);
00041       
00042       Value *V = Constant::getNullValue(Type::IntTy);
00043       MF.getInfo<SparcV9FunctionInfo>()->allocateLocalVar(V, 2*Size);
00044       return true;
00045     }
00046   };
00047 }
00048 
00049 FunctionPass *llvm::createStackSlotsPass(const TargetMachine &Target) {
00050   return new StackSlots(Target);
00051 }
00052