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llvm-6502/lib/Target/Sparc/InstSelectSimple.cpp
Brian Gaeke 6c868a4c17 Support generating machine instructions for Phi nodes (based on x86, but with 
modifications for 1 LLVM BB --> many MBBs).
Fix store operand order: make it always be Base, Offset, SrcReg (think
"[ Base + Offset ] = SrcReg").
Rewrite visitBranchInst() to be even dumber (but working) -- give up on
the branch fallthrough trick, for the time being.
Make visitSetCondInst() work.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14208 91177308-0d34-0410-b5e6-96231b3b80d8
2004-06-17 22:34:08 +00:00

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//===-- 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/IntrinsicLowering.h"
#include "llvm/Pass.h"
#include "llvm/Constants.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFrameInfo.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"
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);
/// 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(Instruction &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 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.
///
/// Long values are handled somewhat specially. They are always allocated
/// as pairs of 32 bit integer values. The register number returned is the
/// lower 32 bits of the long value, and the regNum+1 is the upper 32 bits
/// of the long value.
///
unsigned makeAnotherReg(const Type *Ty) {
assert(dynamic_cast<const SparcV8RegisterInfo*>(TM.getRegisterInfo()) &&
"Current target doesn't have SparcV8 reg info??");
const SparcV8RegisterInfo *MRI =
static_cast<const SparcV8RegisterInfo*>(TM.getRegisterInfo());
if (Ty == Type::LongTy || Ty == Type::ULongTy) {
const TargetRegisterClass *RC = MRI->getRegClassForType(Type::IntTy);
// Create the lower part
F->getSSARegMap()->createVirtualRegister(RC);
// Create the upper part.
return F->getSSARegMap()->createVirtualRegister(RC)-1;
}
// Add the mapping of regnumber => reg class to MachineFunction
const TargetRegisterClass *RC = MRI->getRegClassForType(Ty);
return F->getSSARegMap()->createVirtualRegister(RC);
}
unsigned getReg(Value &V) { return getReg (&V); } // allow refs.
unsigned getReg(Value *V) {
// Just append to the end of the current bb.
MachineBasicBlock::iterator It = BB->end();
return getReg(V, BB, It);
}
unsigned getReg(Value *V, MachineBasicBlock *MBB,
MachineBasicBlock::iterator IPt) {
unsigned &Reg = RegMap[V];
if (Reg == 0) {
Reg = makeAnotherReg(V->getType());
RegMap[V] = Reg;
}
// If this operand is a constant, emit the code to copy the constant into
// the register here...
//
if (Constant *C = dyn_cast<Constant>(V)) {
copyConstantToRegister(MBB, IPt, C, Reg);
RegMap.erase(V); // Assign a new name to this constant if ref'd again
} else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
// Move the address of the global into the register
unsigned TmpReg = makeAnotherReg(V->getType());
BuildMI (*MBB, IPt, V8::SETHIi, 1, TmpReg).addGlobalAddress (GV);
BuildMI (*MBB, IPt, V8::ORri, 2, Reg).addReg (TmpReg)
.addGlobalAddress (GV);
RegMap.erase(V); // Assign a new name to this address if ref'd again
}
return Reg;
}
};
}
FunctionPass *llvm::createSparcV8SimpleInstructionSelector(TargetMachine &TM) {
return new V8ISel(TM);
}
enum TypeClass {
cByte, cShort, cInt, cLong, cFloat, cDouble
};
static TypeClass getClass (const Type *T) {
switch (T->getTypeID()) {
case Type::UByteTyID: case Type::SByteTyID: return cByte;
case Type::UShortTyID: case Type::ShortTyID: return cShort;
case Type::PointerTyID:
case Type::UIntTyID: case Type::IntTyID: return cInt;
case Type::ULongTyID: case Type::LongTyID: return cLong;
case Type::FloatTyID: return cFloat;
case Type::DoubleTyID: return cDouble;
default:
assert (0 && "Type of unknown class passed to getClass?");
return cByte;
}
}
static TypeClass getClassB(const Type *T) {
if (T == Type::BoolTy) return cByte;
return getClass(T);
}
/// copyConstantToRegister - Output the instructions required to put the
/// specified constant into the specified register.
///
void V8ISel::copyConstantToRegister(MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
Constant *C, unsigned R) {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
switch (CE->getOpcode()) {
case Instruction::GetElementPtr:
emitGEPOperation(MBB, IP, CE->getOperand(0),
CE->op_begin()+1, CE->op_end(), R);
return;
default:
std::cerr << "Copying this constant expr not yet handled: " << *CE;
abort();
}
}
if (C->getType()->isIntegral ()) {
uint64_t Val;
unsigned Class = getClassB (C->getType ());
if (Class == cLong) {
unsigned TmpReg = makeAnotherReg (Type::IntTy);
unsigned TmpReg2 = makeAnotherReg (Type::IntTy);
// Copy the value into the register pair.
// R = top(more-significant) half, R+1 = bottom(less-significant) half
uint64_t Val = cast<ConstantInt>(C)->getRawValue();
unsigned topHalf = Val & 0xffffffffU;
unsigned bottomHalf = Val >> 32;
unsigned HH = topHalf >> 10;
unsigned HM = topHalf & 0x03ff;
unsigned LM = bottomHalf >> 10;
unsigned LO = bottomHalf & 0x03ff;
BuildMI (*MBB, IP, V8::SETHIi, 1, TmpReg).addImm(HH);
BuildMI (*MBB, IP, V8::ORri, 2, R).addReg (TmpReg)
.addImm (HM);
BuildMI (*MBB, IP, V8::SETHIi, 1, TmpReg2).addImm(LM);
BuildMI (*MBB, IP, V8::ORri, 2, R+1).addReg (TmpReg2)
.addImm (LO);
return;
}
assert(Class <= cInt && "Type not handled yet!");
if (C->getType() == Type::BoolTy) {
Val = (C == ConstantBool::True);
} else {
ConstantInt *CI = dyn_cast<ConstantInt> (C);
Val = CI->getRawValue ();
}
switch (Class) {
case cByte:
BuildMI (*MBB, IP, V8::ORri, 2, R).addReg (V8::G0).addImm((uint8_t)Val);
return;
case cShort: {
unsigned TmpReg = makeAnotherReg (C->getType ());
BuildMI (*MBB, IP, V8::SETHIi, 1, TmpReg)
.addImm (((uint16_t) Val) >> 10);
BuildMI (*MBB, IP, V8::ORri, 2, R).addReg (TmpReg)
.addImm (((uint16_t) Val) & 0x03ff);
return;
}
case cInt: {
unsigned TmpReg = makeAnotherReg (C->getType ());
BuildMI (*MBB, IP, V8::SETHIi, 1, TmpReg).addImm(((uint32_t)Val) >> 10);
BuildMI (*MBB, IP, V8::ORri, 2, R).addReg (TmpReg)
.addImm (((uint32_t) Val) & 0x03ff);
return;
}
default:
std::cerr << "Offending constant: " << *C << "\n";
assert (0 && "Can't copy this kind of constant into register yet");
return;
}
} else if (isa<ConstantPointerNull>(C)) {
// Copy zero (null pointer) to the register.
BuildMI (*MBB, IP, V8::ORri, 2, R).addReg (V8::G0).addImm (0);
} else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(C)) {
// Copy it with a SETHI/OR pair; the JIT + asmwriter should recognize
// that SETHI %reg,global == SETHI %reg,%hi(global) and
// OR %reg,global,%reg == OR %reg,%lo(global),%reg.
unsigned TmpReg = makeAnotherReg (C->getType ());
BuildMI (*MBB, IP, V8::SETHIi, 1, TmpReg).addGlobalAddress (CPR->getValue());
BuildMI (*MBB, IP, V8::ORri, 2, R).addReg (TmpReg)
.addGlobalAddress (CPR->getValue ());
} else {
std::cerr << "Offending constant: " << *C << "\n";
assert (0 && "Can't copy this kind of constant into register yet");
}
}
void V8ISel::LoadArgumentsToVirtualRegs (Function *F) {
unsigned ArgOffset = 0;
static const unsigned IncomingArgRegs[] = { V8::I0, V8::I1, V8::I2,
V8::I3, V8::I4, V8::I5 };
assert (F->asize () < 7
&& "Can't handle loading excess call args off the stack yet");
for (Function::aiterator I = F->abegin(), E = F->aend(); I != E; ++I) {
unsigned Reg = getReg(*I);
switch (getClassB(I->getType())) {
case cByte:
case cShort:
case cInt:
BuildMI(BB, V8::ORrr, 2, Reg).addReg (V8::G0)
.addReg (IncomingArgRegs[ArgOffset]);
break;
default:
assert (0 && "Only <=32-bit, integral arguments currently handled");
return;
}
++ArgOffset;
}
}
void V8ISel::SelectPHINodes() {
const TargetInstrInfo &TII = *TM.getInstrInfo();
const Function &LF = *F->getFunction(); // The LLVM function...
for (Function::const_iterator I = LF.begin(), E = LF.end(); I != E; ++I) {
const BasicBlock *BB = I;
MachineBasicBlock &MBB = *MBBMap[I];
// Loop over all of the PHI nodes in the LLVM basic block...
MachineBasicBlock::iterator PHIInsertPoint = MBB.begin();
for (BasicBlock::const_iterator I = BB->begin();
PHINode *PN = const_cast<PHINode*>(dyn_cast<PHINode>(I)); ++I) {
// Create a new machine instr PHI node, and insert it.
unsigned PHIReg = getReg(*PN);
MachineInstr *PhiMI = BuildMI(MBB, PHIInsertPoint,
V8::PHI, PN->getNumOperands(), PHIReg);
MachineInstr *LongPhiMI = 0;
if (PN->getType() == Type::LongTy || PN->getType() == Type::ULongTy)
LongPhiMI = BuildMI(MBB, PHIInsertPoint,
V8::PHI, PN->getNumOperands(), PHIReg+1);
// PHIValues - Map of blocks to incoming virtual registers. We use this
// so that we only initialize one incoming value for a particular block,
// even if the block has multiple entries in the PHI node.
//
std::map<MachineBasicBlock*, unsigned> PHIValues;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
MachineBasicBlock *PredMBB = 0;
for (MachineBasicBlock::pred_iterator PI = MBB.pred_begin (),
PE = MBB.pred_end (); PI != PE; ++PI)
if (PN->getIncomingBlock(i) == (*PI)->getBasicBlock()) {
PredMBB = *PI;
break;
}
assert (PredMBB && "Couldn't find incoming machine-cfg edge for phi");
unsigned ValReg;
std::map<MachineBasicBlock*, unsigned>::iterator EntryIt =
PHIValues.lower_bound(PredMBB);
if (EntryIt != PHIValues.end() && EntryIt->first == PredMBB) {
// We already inserted an initialization of the register for this
// predecessor. Recycle it.
ValReg = EntryIt->second;
} else {
// Get the incoming value into a virtual register.
//
Value *Val = PN->getIncomingValue(i);
// If this is a constant or GlobalValue, we may have to insert code
// into the basic block to compute it into a virtual register.
if ((isa<Constant>(Val) && !isa<ConstantExpr>(Val)) ||
isa<GlobalValue>(Val)) {
// Simple constants get emitted at the end of the basic block,
// before any terminator instructions. We "know" that the code to
// move a constant into a register will never clobber any flags.
ValReg = getReg(Val, PredMBB, PredMBB->getFirstTerminator());
} else {
// Because we don't want to clobber any values which might be in
// physical registers with the computation of this constant (which
// might be arbitrarily complex if it is a constant expression),
// just insert the computation at the top of the basic block.
MachineBasicBlock::iterator PI = PredMBB->begin();
// Skip over any PHI nodes though!
while (PI != PredMBB->end() && PI->getOpcode() == V8::PHI)
++PI;
ValReg = getReg(Val, PredMBB, PI);
}
// Remember that we inserted a value for this PHI for this predecessor
PHIValues.insert(EntryIt, std::make_pair(PredMBB, ValReg));
}
PhiMI->addRegOperand(ValReg);
PhiMI->addMachineBasicBlockOperand(PredMBB);
if (LongPhiMI) {
LongPhiMI->addRegOperand(ValReg+1);
LongPhiMI->addMachineBasicBlockOperand(PredMBB);
}
}
// Now that we emitted all of the incoming values for the PHI node, make
// sure to reposition the InsertPoint after the PHI that we just added.
// This is needed because we might have inserted a constant into this
// block, right after the PHI's which is before the old insert point!
PHIInsertPoint = LongPhiMI ? LongPhiMI : PhiMI;
++PHIInsertPoint;
}
}
}
bool V8ISel::runOnFunction(Function &Fn) {
// First pass over the function, lower any unknown intrinsic functions
// with the IntrinsicLowering class.
LowerUnknownIntrinsicFunctionCalls(Fn);
F = &MachineFunction::construct(&Fn, TM);
// Create all of the machine basic blocks for the function...
for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
F->getBasicBlockList().push_back(MBBMap[I] = new MachineBasicBlock(I));
BB = &F->front();
// Set up a frame object for the return address. This is used by the
// llvm.returnaddress & llvm.frameaddress intrinisics.
//ReturnAddressIndex = F->getFrameInfo()->CreateFixedObject(4, -4);
// Copy incoming arguments off of the stack and out of fixed registers.
LoadArgumentsToVirtualRegs(&Fn);
// Instruction select everything except PHI nodes
visit(Fn);
// Select the PHI nodes
SelectPHINodes();
RegMap.clear();
MBBMap.clear();
F = 0;
// We always build a machine code representation for the function
return true;
}
void V8ISel::visitCastInst(CastInst &I) {
unsigned SrcReg = getReg (I.getOperand (0));
unsigned DestReg = getReg (I);
const Type *oldTy = I.getOperand (0)->getType ();
const Type *newTy = I.getType ();
unsigned oldTyClass = getClassB (oldTy);
unsigned newTyClass = getClassB (newTy);
if (oldTyClass < cLong && newTyClass < cLong) {
if (oldTyClass >= newTyClass) {
// Emit a reg->reg copy to do a equal-size or narrowing cast,
// and do sign/zero extension (necessary if we change signedness).
unsigned TmpReg1 = makeAnotherReg (newTy);
unsigned TmpReg2 = makeAnotherReg (newTy);
BuildMI (BB, V8::ORrr, 2, TmpReg1).addReg (V8::G0).addReg (SrcReg);
unsigned shiftWidth = 32 - (8 * TM.getTargetData ().getTypeSize (newTy));
BuildMI (BB, V8::SLLri, 2, TmpReg2).addZImm (shiftWidth).addReg(TmpReg1);
if (newTy->isSigned ()) { // sign-extend with SRA
BuildMI(BB, V8::SRAri, 2, DestReg).addZImm (shiftWidth).addReg(TmpReg2);
} else { // zero-extend with SRL
BuildMI(BB, V8::SRLri, 2, DestReg).addZImm (shiftWidth).addReg(TmpReg2);
}
} else {
unsigned TmpReg1 = makeAnotherReg (oldTy);
unsigned TmpReg2 = makeAnotherReg (newTy);
unsigned TmpReg3 = makeAnotherReg (newTy);
// Widening integer cast. Make sure it's fully sign/zero-extended
// wrt the input type, then make sure it's fully sign/zero-extended wrt
// the output type. Kind of stupid, but simple...
unsigned shiftWidth = 32 - (8 * TM.getTargetData ().getTypeSize (oldTy));
BuildMI (BB, V8::SLLri, 2, TmpReg1).addZImm (shiftWidth).addReg(SrcReg);
if (oldTy->isSigned ()) { // sign-extend with SRA
BuildMI(BB, V8::SRAri, 2, TmpReg2).addZImm (shiftWidth).addReg(TmpReg1);
} else { // zero-extend with SRL
BuildMI(BB, V8::SRLri, 2, TmpReg2).addZImm (shiftWidth).addReg(TmpReg1);
}
shiftWidth = 32 - (8 * TM.getTargetData ().getTypeSize (newTy));
BuildMI (BB, V8::SLLri, 2, TmpReg3).addZImm (shiftWidth).addReg(TmpReg2);
if (newTy->isSigned ()) { // sign-extend with SRA
BuildMI(BB, V8::SRAri, 2, DestReg).addZImm (shiftWidth).addReg(TmpReg3);
} else { // zero-extend with SRL
BuildMI(BB, V8::SRLri, 2, DestReg).addZImm (shiftWidth).addReg(TmpReg3);
}
}
} else {
std::cerr << "Casts w/ long, fp, double still unsupported: " << I;
abort ();
}
}
void V8ISel::visitLoadInst(LoadInst &I) {
unsigned DestReg = getReg (I);
unsigned PtrReg = getReg (I.getOperand (0));
switch (getClassB (I.getType ())) {
case cByte:
if (I.getType ()->isSigned ())
BuildMI (BB, V8::LDSBmr, 1, DestReg).addReg (PtrReg).addSImm(0);
else
BuildMI (BB, V8::LDUBmr, 1, DestReg).addReg (PtrReg).addSImm(0);
return;
case cShort:
if (I.getType ()->isSigned ())
BuildMI (BB, V8::LDSHmr, 1, DestReg).addReg (PtrReg).addSImm(0);
else
BuildMI (BB, V8::LDUHmr, 1, DestReg).addReg (PtrReg).addSImm(0);
return;
case cInt:
BuildMI (BB, V8::LDmr, 1, DestReg).addReg (PtrReg).addSImm(0);
return;
case cLong:
BuildMI (BB, V8::LDDmr, 1, DestReg).addReg (PtrReg).addSImm(0);
return;
default:
std::cerr << "Load instruction not handled: " << I;
abort ();
return;
}
}
void V8ISel::visitStoreInst(StoreInst &I) {
Value *SrcVal = I.getOperand (0);
unsigned SrcReg = getReg (SrcVal);
unsigned PtrReg = getReg (I.getOperand (1));
switch (getClassB (SrcVal->getType ())) {
case cByte:
BuildMI (BB, V8::STBrm, 3).addReg (PtrReg).addSImm (0).addReg (SrcReg);
return;
case cShort:
BuildMI (BB, V8::STHrm, 3).addReg (PtrReg).addSImm (0).addReg (SrcReg);
return;
case cInt:
BuildMI (BB, V8::STrm, 3).addReg (PtrReg).addSImm (0).addReg (SrcReg);
return;
case cLong:
BuildMI (BB, V8::STDrm, 3).addReg (PtrReg).addSImm (0).addReg (SrcReg);
return;
default:
std::cerr << "Store instruction not handled: " << I;
abort ();
return;
}
}
void V8ISel::visitCallInst(CallInst &I) {
assert (I.getNumOperands () < 8
&& "Can't handle pushing excess call args on the stack yet");
static const unsigned OutgoingArgRegs[] = { V8::O0, V8::O1, V8::O2, V8::O3,
V8::O4, V8::O5 };
for (unsigned i = 1; i < 7; ++i)
if (i < I.getNumOperands ()) {
unsigned ArgReg = getReg (I.getOperand (i));
// Schlep it over into the incoming arg register
BuildMI (BB, V8::ORrr, 2, OutgoingArgRegs[i - 1]).addReg (V8::G0)
.addReg (ArgReg);
}
BuildMI (BB, V8::CALL, 1).addGlobalAddress(I.getCalledFunction (), true);
if (I.getType () == Type::VoidTy)
return;
unsigned DestReg = getReg (I);
// Deal w/ return value
switch (getClass (I.getType ())) {
case cByte:
case cShort:
case cInt:
// Schlep it over into the destination register
BuildMI (BB, V8::ORrr, 2, DestReg).addReg(V8::G0).addReg(V8::O0);
break;
default:
std::cerr << "Return type of call instruction not handled: " << I;
abort ();
}
}
void V8ISel::visitReturnInst(ReturnInst &I) {
if (I.getNumOperands () == 1) {
unsigned RetValReg = getReg (I.getOperand (0));
switch (getClass (I.getOperand (0)->getType ())) {
case cByte:
case cShort:
case cInt:
// Schlep it over into i0 (where it will become o0 after restore).
BuildMI (BB, V8::ORrr, 2, V8::I0).addReg(V8::G0).addReg(RetValReg);
break;
default:
std::cerr << "Return instruction of this type not handled: " << I;
abort ();
}
}
// Just emit a 'retl' instruction to return.
BuildMI(BB, V8::RETL, 0);
return;
}
static inline BasicBlock *getBlockAfter(BasicBlock *BB) {
Function::iterator I = BB; ++I; // Get iterator to next block
return I != BB->getParent()->end() ? &*I : 0;
}
/// visitBranchInst - Handles conditional and unconditional branches.
///
void V8ISel::visitBranchInst(BranchInst &I) {
BasicBlock *takenSucc = I.getSuccessor (0);
MachineBasicBlock *takenSuccMBB = MBBMap[takenSucc];
BB->addSuccessor (takenSuccMBB);
if (I.isConditional()) { // conditional branch
BasicBlock *notTakenSucc = I.getSuccessor (1);
MachineBasicBlock *notTakenSuccMBB = MBBMap[notTakenSucc];
BB->addSuccessor (notTakenSuccMBB);
// CondReg=(<condition>);
// If (CondReg==0) goto notTakenSuccMBB;
unsigned CondReg = getReg (I.getCondition ());
BuildMI (BB, V8::CMPri, 2).addSImm (0).addReg (CondReg);
BuildMI (BB, V8::BE, 1).addMBB (notTakenSuccMBB);
}
// goto takenSuccMBB;
BuildMI (BB, V8::BA, 1).addMBB (takenSuccMBB);
}
/// emitGEPOperation - Common code shared between visitGetElementPtrInst and
/// constant expression GEP support.
///
void V8ISel::emitGEPOperation (MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
Value *Src, User::op_iterator IdxBegin,
User::op_iterator IdxEnd, unsigned TargetReg) {
const TargetData &TD = TM.getTargetData ();
const Type *Ty = Src->getType ();
unsigned basePtrReg = getReg (Src);
// GEPs have zero or more indices; we must perform a struct access
// or array access for each one.
for (GetElementPtrInst::op_iterator oi = IdxBegin, oe = IdxEnd; oi != oe;
++oi) {
Value *idx = *oi;
unsigned nextBasePtrReg = makeAnotherReg (Type::UIntTy);
if (const StructType *StTy = dyn_cast<StructType> (Ty)) {
// It's a struct access. idx is the index into the structure,
// which names the field. Use the TargetData structure to
// pick out what the layout of the structure is in memory.
// Use the (constant) structure index's value to find the
// right byte offset from the StructLayout class's list of
// structure member offsets.
unsigned fieldIndex = cast<ConstantUInt> (idx)->getValue ();
unsigned memberOffset =
TD.getStructLayout (StTy)->MemberOffsets[fieldIndex];
// Emit an ADD to add memberOffset to the basePtr.
BuildMI (*MBB, IP, V8::ADDri, 2,
nextBasePtrReg).addReg (basePtrReg).addZImm (memberOffset);
// The next type is the member of the structure selected by the
// index.
Ty = StTy->getElementType (fieldIndex);
} else if (const SequentialType *SqTy = dyn_cast<SequentialType> (Ty)) {
// It's an array or pointer access: [ArraySize x ElementType].
// We want to add basePtrReg to (idxReg * sizeof ElementType). First, we
// must find the size of the pointed-to type (Not coincidentally, the next
// type is the type of the elements in the array).
Ty = SqTy->getElementType ();
unsigned elementSize = TD.getTypeSize (Ty);
unsigned idxReg = getReg (idx, MBB, IP);
unsigned OffsetReg = makeAnotherReg (Type::IntTy);
unsigned elementSizeReg = makeAnotherReg (Type::UIntTy);
BuildMI (*MBB, IP, V8::ORri, 2,
elementSizeReg).addZImm (elementSize).addReg (V8::G0);
// Emit a SMUL to multiply the register holding the index by
// elementSize, putting the result in OffsetReg.
BuildMI (*MBB, IP, V8::SMULrr, 2,
OffsetReg).addReg (elementSizeReg).addReg (idxReg);
// Emit an ADD to add OffsetReg to the basePtr.
BuildMI (*MBB, IP, V8::ADDrr, 2,
nextBasePtrReg).addReg (basePtrReg).addReg (OffsetReg);
}
basePtrReg = nextBasePtrReg;
}
// After we have processed all the indices, the result is left in
// basePtrReg. Move it to the register where we were expected to
// put the answer.
BuildMI (BB, V8::ORrr, 1, TargetReg).addReg (V8::G0).addReg (basePtrReg);
}
void V8ISel::visitGetElementPtrInst (GetElementPtrInst &I) {
unsigned outputReg = getReg (I);
emitGEPOperation (BB, BB->end (), I.getOperand (0),
I.op_begin ()+1, I.op_end (), outputReg);
}
void V8ISel::visitBinaryOperator (Instruction &I) {
unsigned DestReg = getReg (I);
unsigned Op0Reg = getReg (I.getOperand (0));
unsigned Op1Reg = getReg (I.getOperand (1));
unsigned ResultReg = DestReg;
if (getClassB(I.getType()) != cInt)
ResultReg = makeAnotherReg (I.getType ());
unsigned OpCase = ~0;
// FIXME: support long, ulong, fp.
switch (I.getOpcode ()) {
case Instruction::Add: OpCase = 0; break;
case Instruction::Sub: OpCase = 1; break;
case Instruction::Mul: OpCase = 2; break;
case Instruction::And: OpCase = 3; break;
case Instruction::Or: OpCase = 4; break;
case Instruction::Xor: OpCase = 5; break;
case Instruction::Shl: OpCase = 6; break;
case Instruction::Shr: OpCase = 7+I.getType()->isSigned(); break;
case Instruction::Div:
case Instruction::Rem: {
unsigned Dest = ResultReg;
if (I.getOpcode() == Instruction::Rem)
Dest = makeAnotherReg(I.getType());
// FIXME: this is probably only right for 32 bit operands.
if (I.getType ()->isSigned()) {
unsigned Tmp = makeAnotherReg (I.getType ());
// Sign extend into the Y register
BuildMI (BB, V8::SRAri, 2, Tmp).addReg (Op0Reg).addZImm (31);
BuildMI (BB, V8::WRrr, 2, V8::Y).addReg (Tmp).addReg (V8::G0);
BuildMI (BB, V8::SDIVrr, 2, Dest).addReg (Op0Reg).addReg (Op1Reg);
} else {
// Zero extend into the Y register, ie, just set it to zero
BuildMI (BB, V8::WRrr, 2, V8::Y).addReg (V8::G0).addReg (V8::G0);
BuildMI (BB, V8::UDIVrr, 2, Dest).addReg (Op0Reg).addReg (Op1Reg);
}
if (I.getOpcode() == Instruction::Rem) {
unsigned Tmp = makeAnotherReg (I.getType ());
BuildMI (BB, V8::SMULrr, 2, Tmp).addReg(Dest).addReg(Op1Reg);
BuildMI (BB, V8::SUBrr, 2, ResultReg).addReg(Op0Reg).addReg(Tmp);
}
break;
}
default:
visitInstruction (I);
return;
}
if (OpCase != ~0U) {
static const unsigned Opcodes[] = {
V8::ADDrr, V8::SUBrr, V8::SMULrr, V8::ANDrr, V8::ORrr, V8::XORrr,
V8::SLLrr, V8::SRLrr, V8::SRArr
};
BuildMI (BB, Opcodes[OpCase], 2, ResultReg).addReg (Op0Reg).addReg (Op1Reg);
}
switch (getClass (I.getType ())) {
case cByte:
if (I.getType ()->isSigned ()) { // add byte
BuildMI (BB, V8::ANDri, 2, DestReg).addReg (ResultReg).addZImm (0xff);
} else { // add ubyte
unsigned TmpReg = makeAnotherReg (I.getType ());
BuildMI (BB, V8::SLLri, 2, TmpReg).addReg (ResultReg).addZImm (24);
BuildMI (BB, V8::SRAri, 2, DestReg).addReg (TmpReg).addZImm (24);
}
break;
case cShort:
if (I.getType ()->isSigned ()) { // add short
unsigned TmpReg = makeAnotherReg (I.getType ());
BuildMI (BB, V8::SLLri, 2, TmpReg).addReg (ResultReg).addZImm (16);
BuildMI (BB, V8::SRAri, 2, DestReg).addReg (TmpReg).addZImm (16);
} else { // add ushort
unsigned TmpReg = makeAnotherReg (I.getType ());
BuildMI (BB, V8::SLLri, 2, TmpReg).addReg (ResultReg).addZImm (16);
BuildMI (BB, V8::SRLri, 2, DestReg).addReg (TmpReg).addZImm (16);
}
break;
case cInt:
// Nothing todo here.
break;
default:
visitInstruction (I);
return;
}
}
void V8ISel::visitSetCondInst(Instruction &I) {
unsigned Op0Reg = getReg (I.getOperand (0));
unsigned Op1Reg = getReg (I.getOperand (1));
unsigned DestReg = getReg (I);
const Type *Ty = I.getOperand (0)->getType ();
// Compare the two values.
BuildMI(BB, V8::SUBCCrr, 2, V8::G0).addReg(Op0Reg).addReg(Op1Reg);
unsigned BranchIdx;
switch (I.getOpcode()) {
default: assert(0 && "Unknown setcc instruction!");
case Instruction::SetEQ: BranchIdx = 0; break;
case Instruction::SetNE: BranchIdx = 1; break;
case Instruction::SetLT: BranchIdx = 2; break;
case Instruction::SetGT: BranchIdx = 3; break;
case Instruction::SetLE: BranchIdx = 4; break;
case Instruction::SetGE: BranchIdx = 5; break;
}
static unsigned OpcodeTab[12] = {
// LLVM SparcV8
// unsigned signed
V8::BE, V8::BE, // seteq = be be
V8::BNE, V8::BNE, // setne = bne bne
V8::BCS, V8::BL, // setlt = bcs bl
V8::BGU, V8::BG, // setgt = bgu bg
V8::BLEU, V8::BLE, // setle = bleu ble
V8::BCC, V8::BGE // setge = bcc bge
};
unsigned Opcode = OpcodeTab[2*BranchIdx + (Ty->isSigned() ? 1 : 0)];
MachineBasicBlock *thisMBB = BB;
const BasicBlock *LLVM_BB = BB->getBasicBlock ();
// thisMBB:
// ...
// subcc %reg0, %reg1, %g0
// bCC copy1MBB
// ba copy0MBB
// FIXME: we wouldn't need copy0MBB (we could fold it into thisMBB)
// if we could insert other, non-terminator instructions after the
// bCC. But MBB->getFirstTerminator() can't understand this.
MachineBasicBlock *copy1MBB = new MachineBasicBlock (LLVM_BB);
F->getBasicBlockList ().push_back (copy1MBB);
BuildMI (BB, Opcode, 1).addMBB (copy1MBB);
MachineBasicBlock *copy0MBB = new MachineBasicBlock (LLVM_BB);
F->getBasicBlockList ().push_back (copy0MBB);
BuildMI (BB, V8::BA, 1).addMBB (copy0MBB);
// Update machine-CFG edges
BB->addSuccessor (copy1MBB);
BB->addSuccessor (copy0MBB);
// copy0MBB:
// %FalseValue = or %G0, 0
// ba sinkMBB
BB = copy0MBB;
unsigned FalseValue = makeAnotherReg (I.getType ());
BuildMI (BB, V8::ORri, 2, FalseValue).addReg (V8::G0).addZImm (0);
MachineBasicBlock *sinkMBB = new MachineBasicBlock (LLVM_BB);
F->getBasicBlockList ().push_back (sinkMBB);
BuildMI (BB, V8::BA, 1).addMBB (sinkMBB);
// Update machine-CFG edges
BB->addSuccessor (sinkMBB);
DEBUG (std::cerr << "thisMBB is at " << (void*)thisMBB << "\n");
DEBUG (std::cerr << "copy1MBB is at " << (void*)copy1MBB << "\n");
DEBUG (std::cerr << "copy0MBB is at " << (void*)copy0MBB << "\n");
DEBUG (std::cerr << "sinkMBB is at " << (void*)sinkMBB << "\n");
// copy1MBB:
// %TrueValue = or %G0, 1
// ba sinkMBB
BB = copy1MBB;
unsigned TrueValue = makeAnotherReg (I.getType ());
BuildMI (BB, V8::ORri, 2, TrueValue).addReg (V8::G0).addZImm (1);
BuildMI (BB, V8::BA, 1).addMBB (sinkMBB);
// Update machine-CFG edges
BB->addSuccessor (sinkMBB);
// sinkMBB:
// %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, copy1MBB ]
// ...
BB = sinkMBB;
BuildMI (BB, V8::PHI, 4, DestReg).addReg (FalseValue)
.addMBB (copy0MBB).addReg (TrueValue).addMBB (copy1MBB);
}
/// LowerUnknownIntrinsicFunctionCalls - This performs a prepass over the
/// function, lowering any calls to unknown intrinsic functions into the
/// equivalent LLVM code.
void V8ISel::LowerUnknownIntrinsicFunctionCalls(Function &F) {
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
if (CallInst *CI = dyn_cast<CallInst>(I++))
if (Function *F = CI->getCalledFunction())
switch (F->getIntrinsicID()) {
case Intrinsic::not_intrinsic: break;
default:
// All other intrinsic calls we must lower.
Instruction *Before = CI->getPrev();
TM.getIntrinsicLowering().LowerIntrinsicCall(CI);
if (Before) { // Move iterator to instruction after call
I = Before; ++I;
} else {
I = BB->begin();
}
}
}
void V8ISel::visitIntrinsicCall(Intrinsic::ID ID, CallInst &CI) {
unsigned TmpReg1, TmpReg2;
switch (ID) {
default: assert(0 && "Intrinsic not supported!");
}
}
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