path: root/lib/Target/Sparc/InstSelectSimple.cpp

//===-- InstSelectSimple.cpp - A simple instruction selector for SparcV8 --===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file defines a simple peephole instruction selector for the V8 target
//
//===----------------------------------------------------------------------===//

#include "SparcV8.h"
#include "SparcV8InstrInfo.h"
#include "Support/Debug.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Constants.h"
#include "llvm/CodeGen/IntrinsicLowering.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/CFG.h"
#include <iostream>
using namespace llvm;

namespace {
  struct V8ISel : public FunctionPass, public InstVisitor<V8ISel> {
    TargetMachine &TM;
    MachineFunction *F;                 // The function we are compiling into
    MachineBasicBlock *BB;              // The current MBB we are compiling

    std::map<Value*, unsigned> RegMap;  // Mapping between Val's and SSA Regs

    // MBBMap - Mapping between LLVM BB -> Machine BB
    std::map<const BasicBlock*, MachineBasicBlock*> MBBMap;

    V8ISel(TargetMachine &tm) : TM(tm), F(0), BB(0) {}

    /// runOnFunction - Top level implementation of instruction selection for
    /// the entire function.
    ///
    bool runOnFunction(Function &Fn);

    virtual const char *getPassName() const {
      return "SparcV8 Simple Instruction Selection";
    }

    /// emitGEPOperation - Common code shared between visitGetElementPtrInst and
    /// constant expression GEP support.
    ///
    void emitGEPOperation(MachineBasicBlock *BB, MachineBasicBlock::iterator IP,
                          Value *Src, User::op_iterator IdxBegin,
                          User::op_iterator IdxEnd, unsigned TargetReg);

    /// emitCastOperation - Common code shared between visitCastInst and
    /// constant expression cast support.
    ///
    void emitCastOperation(MachineBasicBlock *BB,MachineBasicBlock::iterator IP,
                           Value *Src, const Type *DestTy, unsigned TargetReg);

    /// visitBasicBlock - This method is called when we are visiting a new basic
    /// block.  This simply creates a new MachineBasicBlock to emit code into
    /// and adds it to the current MachineFunction.  Subsequent visit* for
    /// instructions will be invoked for all instructions in the basic block.
    ///
    void visitBasicBlock(BasicBlock &LLVM_BB) {
      BB = MBBMap[&LLVM_BB];
    }

    void visitBinaryOperator(Instruction &I);
    void visitShiftInst (ShiftInst &SI) { visitBinaryOperator (SI); }
    void visitSetCondInst(SetCondInst &I);
    void visitCallInst(CallInst &I);
    void visitReturnInst(ReturnInst &I);
    void visitBranchInst(BranchInst &I);
    void visitCastInst(CastInst &I);
    void visitLoadInst(LoadInst &I);
    void visitStoreInst(StoreInst &I);
    void visitPHINode(PHINode &I) {}      // PHI nodes handled by second pass
    void visitGetElementPtrInst(GetElementPtrInst &I);
    void visitAllocaInst(AllocaInst &I);

    void visitInstruction(Instruction &I) {
      std::cerr << "Unhandled instruction: " << I;
      abort();
    }

    /// LowerUnknownIntrinsicFunctionCalls - This performs a prepass over the
    /// function, lowering any calls to unknown intrinsic functions into the
    /// equivalent LLVM code.
    void LowerUnknownIntrinsicFunctionCalls(Function &F);
    void visitIntrinsicCall(Intrinsic::ID ID, CallInst &CI);

    void LoadArgumentsToVirtualRegs(Function *F);

    /// SelectPHINodes - Insert machine code to generate phis.  This is tricky
    /// because we have to generate our sources into the source basic blocks,
    /// not the current one.
    ///
    void SelectPHINodes();

    /// copyConstantToRegister - Output the instructions required to put the
    /// specified constant into the specified register.
    ///
    void copyConstantToRegister(MachineBasicBlock *MBB,
                                MachineBasicBlock::iterator IP,
                                Constant *C, unsigned R);

    /// makeAnotherReg - This method returns the next register number we haven't
    /// yet used.