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e35ba65b02
llvm-6502/lib/Target/X86/InstSelectSimple.cpp
Alkis Evlogimenos e35ba65b02 Rename SHL, SHR, SAR, SHLD and SHLR instructions to make them 
consistent with the rest and also pepare for the addition of their
memory operand variants.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11902 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-27 06:57:05 +00:00

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//===-- InstSelectSimple.cpp - A simple instruction selector for x86 ------===//
//
// 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 x86 target
//
//===----------------------------------------------------------------------===//
#include "X86.h"
#include "X86InstrBuilder.h"
#include "X86InstrInfo.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicLowering.h"
#include "llvm/Pass.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/Target/MRegisterInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/CFG.h"
#include "Support/Statistic.h"
using namespace llvm;
namespace {
Statistic<>
NumFPKill("x86-codegen", "Number of FP_REG_KILL instructions added");
}
/// BMI - A special BuildMI variant that takes an iterator to insert the
/// instruction at as well as a basic block. This is the version for when you
/// have a destination register in mind.
inline static MachineInstrBuilder BMI(MachineBasicBlock *MBB,
MachineBasicBlock::iterator I,
int Opcode, unsigned NumOperands,
unsigned DestReg) {
MachineInstr *MI = new MachineInstr(Opcode, NumOperands+1, true, true);
MBB->insert(I, MI);
return MachineInstrBuilder(MI).addReg(DestReg, MachineOperand::Def);
}
/// BMI - A special BuildMI variant that takes an iterator to insert the
/// instruction at as well as a basic block.
inline static MachineInstrBuilder BMI(MachineBasicBlock *MBB,
MachineBasicBlock::iterator I,
int Opcode, unsigned NumOperands) {
MachineInstr *MI = new MachineInstr(Opcode, NumOperands, true, true);
MBB->insert(I, MI);
return MachineInstrBuilder(MI);
}
namespace {
struct ISel : public FunctionPass, InstVisitor<ISel> {
TargetMachine &TM;
MachineFunction *F; // The function we are compiling into
MachineBasicBlock *BB; // The current MBB we are compiling
int VarArgsFrameIndex; // FrameIndex for start of varargs area
int ReturnAddressIndex; // FrameIndex for the return address
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;
ISel(TargetMachine &tm) : TM(tm), F(0), BB(0) {}
/// runOnFunction - Top level implementation of instruction selection for
/// the entire function.
///
bool 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...
LoadArgumentsToVirtualRegs(Fn);
// Instruction select everything except PHI nodes
visit(Fn);
// Select the PHI nodes
SelectPHINodes();
// Insert the FP_REG_KILL instructions into blocks that need them.
InsertFPRegKills();
RegMap.clear();
MBBMap.clear();
F = 0;
// We always build a machine code representation for the function
return true;
}
virtual const char *getPassName() const {
return "X86 Simple Instruction Selection";
}
/// 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];
}
/// LowerUnknownIntrinsicFunctionCalls - This performs a prepass over the
/// function, lowering any calls to unknown intrinsic functions into the
/// equivalent LLVM code.
void LowerUnknownIntrinsicFunctionCalls(Function &F);
/// LoadArgumentsToVirtualRegs - Load all of the arguments to this function
/// from the stack into virtual registers.
///
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();
/// InsertFPRegKills - Insert FP_REG_KILL instructions into basic blocks
/// that need them. This only occurs due to the floating point stackifier
/// not being aggressive enough to handle arbitrary global stackification.
///
void InsertFPRegKills();
// Visitation methods for various instructions. These methods simply emit
// fixed X86 code for each instruction.
//
// Control flow operators
void visitReturnInst(ReturnInst &RI);
void visitBranchInst(BranchInst &BI);
struct ValueRecord {
Value *Val;
unsigned Reg;
const Type *Ty;
ValueRecord(unsigned R, const Type *T) : Val(0), Reg(R), Ty(T) {}
ValueRecord(Value *V) : Val(V), Reg(0), Ty(V->getType()) {}
};
void doCall(const ValueRecord &Ret, MachineInstr *CallMI,
const std::vector<ValueRecord> &Args);
void visitCallInst(CallInst &I);
void visitIntrinsicCall(Intrinsic::ID ID, CallInst &I);
// Arithmetic operators
void visitSimpleBinary(BinaryOperator &B, unsigned OpcodeClass);
void visitAdd(BinaryOperator &B) { visitSimpleBinary(B, 0); }
void visitSub(BinaryOperator &B) { visitSimpleBinary(B, 1); }
void doMultiply(MachineBasicBlock *MBB, MachineBasicBlock::iterator MBBI,
unsigned DestReg, const Type *DestTy,
unsigned Op0Reg, unsigned Op1Reg);
void doMultiplyConst(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI,
unsigned DestReg, const Type *DestTy,
unsigned Op0Reg, unsigned Op1Val);
void visitMul(BinaryOperator &B);
void visitDiv(BinaryOperator &B) { visitDivRem(B); }
void visitRem(BinaryOperator &B) { visitDivRem(B); }
void visitDivRem(BinaryOperator &B);
// Bitwise operators
void visitAnd(BinaryOperator &B) { visitSimpleBinary(B, 2); }
void visitOr (BinaryOperator &B) { visitSimpleBinary(B, 3); }
void visitXor(BinaryOperator &B) { visitSimpleBinary(B, 4); }
// Comparison operators...
void visitSetCondInst(SetCondInst &I);
unsigned EmitComparison(unsigned OpNum, Value *Op0, Value *Op1,
MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI);
// Memory Instructions
void visitLoadInst(LoadInst &I);
void visitStoreInst(StoreInst &I);
void visitGetElementPtrInst(GetElementPtrInst &I);
void visitAllocaInst(AllocaInst &I);
void visitMallocInst(MallocInst &I);
void visitFreeInst(FreeInst &I);
// Other operators
void visitShiftInst(ShiftInst &I);
void visitPHINode(PHINode &I) {} // PHI nodes handled by second pass
void visitCastInst(CastInst &I);
void visitVANextInst(VANextInst &I);
void visitVAArgInst(VAArgInst &I);
void visitInstruction(Instruction &I) {
std::cerr << "Cannot instruction select: " << I;
abort();
}
/// promote32 - Make a value 32-bits wide, and put it somewhere.
///
void promote32(unsigned targetReg, const ValueRecord &VR);
// getGEPIndex - This is used to fold GEP instructions into X86 addressing
// expressions.
void getGEPIndex(MachineBasicBlock *MBB, MachineBasicBlock::iterator IP,
std::vector<Value*> &GEPOps,
std::vector<const Type*> &GEPTypes, unsigned &BaseReg,
unsigned &Scale, unsigned &IndexReg, unsigned &Disp);
/// isGEPFoldable - Return true if the specified GEP can be completely
/// folded into the addressing mode of a load/store or lea instruction.
bool isGEPFoldable(MachineBasicBlock *MBB,
Value *Src, User::op_iterator IdxBegin,
User::op_iterator IdxEnd, unsigned &BaseReg,
unsigned &Scale, unsigned &IndexReg, unsigned &Disp);
/// 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);
/// emitSimpleBinaryOperation - Common code shared between visitSimpleBinary
/// and constant expression support.
void emitSimpleBinaryOperation(MachineBasicBlock *BB,
MachineBasicBlock::iterator IP,
Value *Op0, Value *Op1,
unsigned OperatorClass, unsigned TargetReg);
void emitDivRemOperation(MachineBasicBlock *BB,
MachineBasicBlock::iterator IP,
unsigned Op0Reg, unsigned Op1Reg, bool isDiv,
const Type *Ty, unsigned TargetReg);
/// emitSetCCOperation - Common code shared between visitSetCondInst and
/// constant expression support.
void emitSetCCOperation(MachineBasicBlock *BB,
MachineBasicBlock::iterator IP,
Value *Op0, Value *Op1, unsigned Opcode,
unsigned TargetReg);
/// emitShiftOperation - Common code shared between visitShiftInst and
/// constant expression support.
void emitShiftOperation(MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
Value *Op, Value *ShiftAmount, bool isLeftShift,
const Type *ResultTy, unsigned DestReg);
/// copyConstantToRegister - Output the instructions required to put the
/// specified constant into the specified register.
///
void copyConstantToRegister(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI,
Constant *C, unsigned Reg);
/// 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 X86RegisterInfo*>(TM.getRegisterInfo()) &&
"Current target doesn't have X86 reg info??");
const X86RegisterInfo *MRI =
static_cast<const X86RegisterInfo*>(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);
}
/// getReg - This method turns an LLVM value into a register number. This
/// is guaranteed to produce the same register number for a particular value
/// every time it is queried.
///
unsigned getReg(Value &V) { return getReg(&V); } // Allow references
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
BMI(MBB, IPt, X86::MOVri32, 1, Reg).addGlobalAddress(GV);
RegMap.erase(V); // Assign a new name to this address if ref'd again
}
return Reg;
}
};
}
/// TypeClass - Used by the X86 backend to group LLVM types by their basic X86
/// Representation.
///
enum TypeClass {
cByte, cShort, cInt, cFP, cLong
};
/// getClass - Turn a primitive type into a "class" number which is based on the
/// size of the type, and whether or not it is floating point.
///
static inline TypeClass getClass(const Type *Ty) {
switch (Ty->getPrimitiveID()) {
case Type::SByteTyID:
case Type::UByteTyID: return cByte; // Byte operands are class #0
case Type::ShortTyID:
case Type::UShortTyID: return cShort; // Short operands are class #1
case Type::IntTyID:
case Type::UIntTyID:
case Type::PointerTyID: return cInt; // Int's and pointers are class #2
case Type::FloatTyID:
case Type::DoubleTyID: return cFP; // Floating Point is #3
case Type::LongTyID:
case Type::ULongTyID: return cLong; // Longs are class #4
default:
assert(0 && "Invalid type to getClass!");
return cByte; // not reached
}
}
// getClassB - Just like getClass, but treat boolean values as bytes.
static inline TypeClass getClassB(const Type *Ty) {
if (Ty == Type::BoolTy) return cByte;
return getClass(Ty);
}
/// copyConstantToRegister - Output the instructions required to put the
/// specified constant into the specified register.
///
void ISel::copyConstantToRegister(MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
Constant *C, unsigned R) {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
unsigned Class = 0;
switch (CE->getOpcode()) {
case Instruction::GetElementPtr:
emitGEPOperation(MBB, IP, CE->getOperand(0),
CE->op_begin()+1, CE->op_end(), R);
return;
case Instruction::Cast:
emitCastOperation(MBB, IP, CE->getOperand(0), CE->getType(), R);
return;
case Instruction::Xor: ++Class; // FALL THROUGH
case Instruction::Or: ++Class; // FALL THROUGH
case Instruction::And: ++Class; // FALL THROUGH
case Instruction::Sub: ++Class; // FALL THROUGH
case Instruction::Add:
emitSimpleBinaryOperation(MBB, IP, CE->getOperand(0), CE->getOperand(1),
Class, R);
return;
case Instruction::Mul: {
unsigned Op0Reg = getReg(CE->getOperand(0), MBB, IP);
unsigned Op1Reg = getReg(CE->getOperand(1), MBB, IP);
doMultiply(MBB, IP, R, CE->getType(), Op0Reg, Op1Reg);
return;
}
case Instruction::Div:
case Instruction::Rem: {
unsigned Op0Reg = getReg(CE->getOperand(0), MBB, IP);
unsigned Op1Reg = getReg(CE->getOperand(1), MBB, IP);
emitDivRemOperation(MBB, IP, Op0Reg, Op1Reg,
CE->getOpcode() == Instruction::Div,
CE->getType(), R);
return;
}
case Instruction::SetNE:
case Instruction::SetEQ:
case Instruction::SetLT:
case Instruction::SetGT:
case Instruction::SetLE:
case Instruction::SetGE:
emitSetCCOperation(MBB, IP, CE->getOperand(0), CE->getOperand(1),
CE->getOpcode(), R);
return;
case Instruction::Shl:
case Instruction::Shr:
emitShiftOperation(MBB, IP, CE->getOperand(0), CE->getOperand(1),
CE->getOpcode() == Instruction::Shl, CE->getType(), R);
return;
default:
std::cerr << "Offending expr: " << C << "\n";
assert(0 && "Constant expression not yet handled!\n");
}
}
if (C->getType()->isIntegral()) {
unsigned Class = getClassB(C->getType());
if (Class == cLong) {
// Copy the value into the register pair.
uint64_t Val = cast<ConstantInt>(C)->getRawValue();
BMI(MBB, IP, X86::MOVri32, 1, R).addZImm(Val & 0xFFFFFFFF);
BMI(MBB, IP, X86::MOVri32, 1, R+1).addZImm(Val >> 32);
return;
}
assert(Class <= cInt && "Type not handled yet!");
static const unsigned IntegralOpcodeTab[] = {
X86::MOVri8, X86::MOVri16, X86::MOVri32
};
if (C->getType() == Type::BoolTy) {
BMI(MBB, IP, X86::MOVri8, 1, R).addZImm(C == ConstantBool::True);
} else {
ConstantInt *CI = cast<ConstantInt>(C);
BMI(MBB, IP, IntegralOpcodeTab[Class], 1, R).addZImm(CI->getRawValue());
}
} else if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
if (CFP->isExactlyValue(+0.0))
BMI(MBB, IP, X86::FLD0, 0, R);
else if (CFP->isExactlyValue(+1.0))
BMI(MBB, IP, X86::FLD1, 0, R);
else {
// Otherwise we need to spill the constant to memory...
MachineConstantPool *CP = F->getConstantPool();
unsigned CPI = CP->getConstantPoolIndex(CFP);
const Type *Ty = CFP->getType();
assert(Ty == Type::FloatTy || Ty == Type::DoubleTy && "Unknown FP type!");
unsigned LoadOpcode = Ty == Type::FloatTy ? X86::FLDr32 : X86::FLDr64;
addConstantPoolReference(BMI(MBB, IP, LoadOpcode, 4, R), CPI);
}
} else if (isa<ConstantPointerNull>(C)) {
// Copy zero (null pointer) to the register.
BMI(MBB, IP, X86::MOVri32, 1, R).addZImm(0);
} else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(C)) {
BMI(MBB, IP, X86::MOVri32, 1, R).addGlobalAddress(CPR->getValue());
} else {
std::cerr << "Offending constant: " << C << "\n";
assert(0 && "Type not handled yet!");
}
}
/// LoadArgumentsToVirtualRegs - Load all of the arguments to this function from
/// the stack into virtual registers.
///
void ISel::LoadArgumentsToVirtualRegs(Function &Fn) {
// Emit instructions to load the arguments... On entry to a function on the
// X86, the stack frame looks like this:
//
// [ESP] -- return address
// [ESP + 4] -- first argument (leftmost lexically)
// [ESP + 8] -- second argument, if first argument is four bytes in size
// ...
//
unsigned ArgOffset = 0; // Frame mechanisms handle retaddr slot
MachineFrameInfo *MFI = F->getFrameInfo();
for (Function::aiterator I = Fn.abegin(), E = Fn.aend(); I != E; ++I) {
unsigned Reg = getReg(*I);
int FI; // Frame object index
switch (getClassB(I->getType())) {
case cByte:
FI = MFI->CreateFixedObject(1, ArgOffset);
addFrameReference(BuildMI(BB, X86::MOVrm8, 4, Reg), FI);
break;
case cShort:
FI = MFI->CreateFixedObject(2, ArgOffset);
addFrameReference(BuildMI(BB, X86::MOVrm16, 4, Reg), FI);
break;
case cInt:
FI = MFI->CreateFixedObject(4, ArgOffset);
addFrameReference(BuildMI(BB, X86::MOVrm32, 4, Reg), FI);
break;
case cLong:
FI = MFI->CreateFixedObject(8, ArgOffset);
addFrameReference(BuildMI(BB, X86::MOVrm32, 4, Reg), FI);
addFrameReference(BuildMI(BB, X86::MOVrm32, 4, Reg+1), FI, 4);
ArgOffset += 4; // longs require 4 additional bytes
break;
case cFP:
unsigned Opcode;
if (I->getType() == Type::FloatTy) {
Opcode = X86::FLDr32;
FI = MFI->CreateFixedObject(4, ArgOffset);
} else {
Opcode = X86::FLDr64;
FI = MFI->CreateFixedObject(8, ArgOffset);
ArgOffset += 4; // doubles require 4 additional bytes
}
addFrameReference(BuildMI(BB, Opcode, 4, Reg), FI);
break;
default:
assert(0 && "Unhandled argument type!");
}
ArgOffset += 4; // Each argument takes at least 4 bytes on the stack...
}
// If the function takes variable number of arguments, add a frame offset for
// the start of the first vararg value... this is used to expand
// llvm.va_start.
if (Fn.getFunctionType()->isVarArg())
VarArgsFrameIndex = MFI->CreateFixedObject(1, ArgOffset);
}
/// 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 ISel::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 instr = 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(X86::PHI, PN->getNumOperands(), PHIReg);
MBB->insert(instr, PhiMI);
MachineInstr *LongPhiMI = 0;
if (PN->getType() == Type::LongTy || PN->getType() == Type::ULongTy) {
LongPhiMI = BuildMI(X86::PHI, PN->getNumOperands(), PHIReg+1);
MBB->insert(instr, LongPhiMI);
}
// 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 = MBBMap[PN->getIncomingBlock(i)];
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<GlobalValue>(Val)) {
// 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() == X86::PHI)
++PI;
ValReg = getReg(Val, PredMBB, PI);
} else {
ValReg = getReg(Val);
}
// 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);
}
}
}
}
}
/// RequiresFPRegKill - The floating point stackifier pass cannot insert
/// compensation code on critical edges. As such, it requires that we kill all
/// FP registers on the exit from any blocks that either ARE critical edges, or
/// branch to a block that has incoming critical edges.
///
/// Note that this kill instruction will eventually be eliminated when
/// restrictions in the stackifier are relaxed.
///
static bool RequiresFPRegKill(const BasicBlock *BB) {
#if 0
for (succ_const_iterator SI = succ_begin(BB), E = succ_end(BB); SI!=E; ++SI) {
const BasicBlock *Succ = *SI;
pred_const_iterator PI = pred_begin(Succ), PE = pred_end(Succ);
++PI; // Block have at least one predecessory
if (PI != PE) { // If it has exactly one, this isn't crit edge
// If this block has more than one predecessor, check all of the
// predecessors to see if they have multiple successors. If so, then the
// block we are analyzing needs an FPRegKill.
for (PI = pred_begin(Succ); PI != PE; ++PI) {
const BasicBlock *Pred = *PI;
succ_const_iterator SI2 = succ_begin(Pred);
++SI2; // There must be at least one successor of this block.
if (SI2 != succ_end(Pred))
return true; // Yes, we must insert the kill on this edge.
}
}
}
// If we got this far, there is no need to insert the kill instruction.
return false;
#else
return true;
#endif
}
// InsertFPRegKills - Insert FP_REG_KILL instructions into basic blocks that
// need them. This only occurs due to the floating point stackifier not being
// aggressive enough to handle arbitrary global stackification.
//
// Currently we insert an FP_REG_KILL instruction into each block that uses or
// defines a floating point virtual register.
//
// When the global register allocators (like linear scan) finally update live
// variable analysis, we can keep floating point values in registers across
// portions of the CFG that do not involve critical edges. This will be a big
// win, but we are waiting on the global allocators before we can do this.
//
// With a bit of work, the floating point stackifier pass can be enhanced to
// break critical edges as needed (to make a place to put compensation code),
// but this will require some infrastructure improvements as well.
//
void ISel::InsertFPRegKills() {
SSARegMap &RegMap = *F->getSSARegMap();
for (MachineFunction::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I!=E; ++I)
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
MachineOperand& MO = I->getOperand(i);
if (MO.isRegister() && MO.getReg()) {
unsigned Reg = MO.getReg();
if (MRegisterInfo::isVirtualRegister(Reg))
if (RegMap.getRegClass(Reg)->getSize() == 10)
goto UsesFPReg;
}
}
// If we haven't found an FP register use or def in this basic block, check
// to see if any of our successors has an FP PHI node, which will cause a
// copy to be inserted into this block.
for (succ_const_iterator SI = succ_begin(BB->getBasicBlock()),
E = succ_end(BB->getBasicBlock()); SI != E; ++SI) {
MachineBasicBlock *SBB = MBBMap[*SI];
for (MachineBasicBlock::iterator I = SBB->begin();
I != SBB->end() && I->getOpcode() == X86::PHI; ++I) {
if (RegMap.getRegClass(I->getOperand(0).getReg())->getSize() == 10)
goto UsesFPReg;
}
}
continue;
UsesFPReg:
// Okay, this block uses an FP register. If the block has successors (ie,
// it's not an unwind/return), insert the FP_REG_KILL instruction.
if (BB->getBasicBlock()->getTerminator()->getNumSuccessors() &&
RequiresFPRegKill(BB->getBasicBlock())) {
BMI(BB, BB->getFirstTerminator(), X86::FP_REG_KILL, 0);
++NumFPKill;
}
}
}
// canFoldSetCCIntoBranch - Return the setcc instruction if we can fold it into
// the conditional branch instruction which is the only user of the cc
// instruction. This is the case if the conditional branch is the only user of
// the setcc, and if the setcc is in the same basic block as the conditional
// branch. We also don't handle long arguments below, so we reject them here as
// well.
//
static SetCondInst *canFoldSetCCIntoBranch(Value *V) {
if (SetCondInst *SCI = dyn_cast<SetCondInst>(V))
if (SCI->hasOneUse() && isa<BranchInst>(SCI->use_back()) &&
SCI->getParent() == cast<BranchInst>(SCI->use_back())->getParent()) {
const Type *Ty = SCI->getOperand(0)->getType();
if (Ty != Type::LongTy && Ty != Type::ULongTy)
return SCI;
}
return 0;
}
// Return a fixed numbering for setcc instructions which does not depend on the
// order of the opcodes.
//
static unsigned getSetCCNumber(unsigned Opcode) {
switch(Opcode) {
default: assert(0 && "Unknown setcc instruction!");
case Instruction::SetEQ: return 0;
case Instruction::SetNE: return 1;
case Instruction::SetLT: return 2;
case Instruction::SetGE: return 3;
case Instruction::SetGT: return 4;
case Instruction::SetLE: return 5;
}
}
// LLVM -> X86 signed X86 unsigned
// ----- ---------- ------------
// seteq -> sete sete
// setne -> setne setne
// setlt -> setl setb
// setge -> setge setae
// setgt -> setg seta
// setle -> setle setbe
// ----
// sets // Used by comparison with 0 optimization
// setns
static const unsigned SetCCOpcodeTab[2][8] = {
{ X86::SETEr, X86::SETNEr, X86::SETBr, X86::SETAEr, X86::SETAr, X86::SETBEr,
0, 0 },
{ X86::SETEr, X86::SETNEr, X86::SETLr, X86::SETGEr, X86::SETGr, X86::SETLEr,
X86::SETSr, X86::SETNSr },
};
// EmitComparison - This function emits a comparison of the two operands,
// returning the extended setcc code to use.
unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1,
MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP) {
// The arguments are already supposed to be of the same type.
const Type *CompTy = Op0->getType();
unsigned Class = getClassB(CompTy);
unsigned Op0r = getReg(Op0, MBB, IP);
// Special case handling of: cmp R, i
if (Class == cByte || Class == cShort || Class == cInt)
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
uint64_t Op1v = cast<ConstantInt>(CI)->getRawValue();
// Mask off any upper bits of the constant, if there are any...
Op1v &= (1ULL << (8 << Class)) - 1;
// If this is a comparison against zero, emit more efficient code. We
// can't handle unsigned comparisons against zero unless they are == or
// !=. These should have been strength reduced already anyway.
if (Op1v == 0 && (CompTy->isSigned() || OpNum < 2)) {
static const unsigned TESTTab[] = {
X86::TESTrr8, X86::TESTrr16, X86::TESTrr32
};
BMI(MBB, IP, TESTTab[Class], 2).addReg(Op0r).addReg(Op0r);
if (OpNum == 2) return 6; // Map jl -> js
if (OpNum == 3) return 7; // Map jg -> jns
return OpNum;
}
static const unsigned CMPTab[] = {
X86::CMPri8, X86::CMPri16, X86::CMPri32
};
BMI(MBB, IP, CMPTab[Class], 2).addReg(Op0r).addZImm(Op1v);
return OpNum;
}
// Special case handling of comparison against +/- 0.0
if (ConstantFP *CFP = dyn_cast<ConstantFP>(Op1))
if (CFP->isExactlyValue(+0.0) || CFP->isExactlyValue(-0.0)) {
BMI(MBB, IP, X86::FTST, 1).addReg(Op0r);
BMI(MBB, IP, X86::FNSTSWr8, 0);
BMI(MBB, IP, X86::SAHF, 1);
return OpNum;
}
unsigned Op1r = getReg(Op1, MBB, IP);
switch (Class) {
default: assert(0 && "Unknown type class!");
// Emit: cmp <var1>, <var2> (do the comparison). We can
// compare 8-bit with 8-bit, 16-bit with 16-bit, 32-bit with
// 32-bit.
case cByte:
BMI(MBB, IP, X86::CMPrr8, 2).addReg(Op0r).addReg(Op1r);
break;
case cShort:
BMI(MBB, IP, X86::CMPrr16, 2).addReg(Op0r).addReg(Op1r);
break;
case cInt:
BMI(MBB, IP, X86::CMPrr32, 2).addReg(Op0r).addReg(Op1r);
break;
case cFP:
BMI(MBB, IP, X86::FpUCOM, 2).addReg(Op0r).addReg(Op1r);
BMI(MBB, IP, X86::FNSTSWr8, 0);
BMI(MBB, IP, X86::SAHF, 1);
break;
case cLong:
if (OpNum < 2) { // seteq, setne
unsigned LoTmp = makeAnotherReg(Type::IntTy);
unsigned HiTmp = makeAnotherReg(Type::IntTy);
unsigned FinalTmp = makeAnotherReg(Type::IntTy);
BMI(MBB, IP, X86::XORrr32, 2, LoTmp).addReg(Op0r).addReg(Op1r);
BMI(MBB, IP, X86::XORrr32, 2, HiTmp).addReg(Op0r+1).addReg(Op1r+1);
BMI(MBB, IP, X86::ORrr32, 2, FinalTmp).addReg(LoTmp).addReg(HiTmp);
break; // Allow the sete or setne to be generated from flags set by OR
} else {
// Emit a sequence of code which compares the high and low parts once
// each, then uses a conditional move to handle the overflow case. For
// example, a setlt for long would generate code like this:
//
// AL = lo(op1) < lo(op2) // Signedness depends on operands
// BL = hi(op1) < hi(op2) // Always unsigned comparison
// dest = hi(op1) == hi(op2) ? AL : BL;
//
// FIXME: This would be much better if we had hierarchical register
// classes! Until then, hardcode registers so that we can deal with their
// aliases (because we don't have conditional byte moves).
//
BMI(MBB, IP, X86::CMPrr32, 2).addReg(Op0r).addReg(Op1r);
BMI(MBB, IP, SetCCOpcodeTab[0][OpNum], 0, X86::AL);
BMI(MBB, IP, X86::CMPrr32, 2).addReg(Op0r+1).addReg(Op1r+1);
BMI(MBB, IP, SetCCOpcodeTab[CompTy->isSigned()][OpNum], 0, X86::BL);
BMI(MBB, IP, X86::IMPLICIT_DEF, 0, X86::BH);
BMI(MBB, IP, X86::IMPLICIT_DEF, 0, X86::AH);
BMI(MBB, IP, X86::CMOVErr16, 2, X86::BX).addReg(X86::BX).addReg(X86::AX);
// NOTE: visitSetCondInst knows that the value is dumped into the BL
// register at this point for long values...
return OpNum;
}
}
return OpNum;
}
/// SetCC instructions - Here we just emit boilerplate code to set a byte-sized
/// register, then move it to wherever the result should be.
///
void ISel::visitSetCondInst(SetCondInst &I) {
if (canFoldSetCCIntoBranch(&I)) return; // Fold this into a branch...
unsigned DestReg = getReg(I);
MachineBasicBlock::iterator MII = BB->end();
emitSetCCOperation(BB, MII, I.getOperand(0), I.getOperand(1), I.getOpcode(),
DestReg);
}
/// emitSetCCOperation - Common code shared between visitSetCondInst and
/// constant expression support.
void ISel::emitSetCCOperation(MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
Value *Op0, Value *Op1, unsigned Opcode,
unsigned TargetReg) {
unsigned OpNum = getSetCCNumber(Opcode);
OpNum = EmitComparison(OpNum, Op0, Op1, MBB, IP);
const Type *CompTy = Op0->getType();
unsigned CompClass = getClassB(CompTy);
bool isSigned = CompTy->isSigned() && CompClass != cFP;
if (CompClass != cLong || OpNum < 2) {
// Handle normal comparisons with a setcc instruction...
BMI(MBB, IP, SetCCOpcodeTab[isSigned][OpNum], 0, TargetReg);
} else {
// Handle long comparisons by copying the value which is already in BL into
// the register we want...
BMI(MBB, IP, X86::MOVrr8, 1, TargetReg).addReg(X86::BL);
}
}
/// promote32 - Emit instructions to turn a narrow operand into a 32-bit-wide
/// operand, in the specified target register.
void ISel::promote32(unsigned targetReg, const ValueRecord &VR) {
bool isUnsigned = VR.Ty->isUnsigned();
// Make sure we have the register number for this value...
unsigned Reg = VR.Val ? getReg(VR.Val) : VR.Reg;
switch (getClassB(VR.Ty)) {
case cByte:
// Extend value into target register (8->32)
if (isUnsigned)
BuildMI(BB, X86::MOVZXr32r8, 1, targetReg).addReg(Reg);
else
BuildMI(BB, X86::MOVSXr32r8, 1, targetReg).addReg(Reg);
break;
case cShort:
// Extend value into target register (16->32)
if (isUnsigned)
BuildMI(BB, X86::MOVZXr32r16, 1, targetReg).addReg(Reg);
else
BuildMI(BB, X86::MOVSXr32r16, 1, targetReg).addReg(Reg);
break;
case cInt:
// Move value into target register (32->32)
BuildMI(BB, X86::MOVrr32, 1, targetReg).addReg(Reg);
break;
default:
assert(0 && "Unpromotable operand class in promote32");
}
}
/// 'ret' instruction - Here we are interested in meeting the x86 ABI. As such,
/// we have the following possibilities:
///
/// ret void: No return value, simply emit a 'ret' instruction
/// ret sbyte, ubyte : Extend value into EAX and return
/// ret short, ushort: Extend value into EAX and return
/// ret int, uint : Move value into EAX and return
/// ret pointer : Move value into EAX and return
/// ret long, ulong : Move value into EAX/EDX and return
/// ret float/double : Top of FP stack
///
void ISel::visitReturnInst(ReturnInst &I) {
if (I.getNumOperands() == 0) {
BuildMI(BB, X86::RET, 0); // Just emit a 'ret' instruction
return;
}
Value *RetVal = I.getOperand(0);
unsigned RetReg = getReg(RetVal);
switch (getClassB(RetVal->getType())) {
case cByte: // integral return values: extend or move into EAX and return
case cShort:
case cInt:
promote32(X86::EAX, ValueRecord(RetReg, RetVal->getType()));
// Declare that EAX is live on exit
BuildMI(BB, X86::IMPLICIT_USE, 2).addReg(X86::EAX).addReg(X86::ESP);
break;
case cFP: // Floats & Doubles: Return in ST(0)
BuildMI(BB, X86::FpSETRESULT, 1).addReg(RetReg);
// Declare that top-of-stack is live on exit
BuildMI(BB, X86::IMPLICIT_USE, 2).addReg(X86::ST0).addReg(X86::ESP);
break;
case cLong:
BuildMI(BB, X86::MOVrr32, 1, X86::EAX).addReg(RetReg);
BuildMI(BB, X86::MOVrr32, 1, X86::EDX).addReg(RetReg+1);
// Declare that EAX & EDX are live on exit
BuildMI(BB, X86::IMPLICIT_USE, 3).addReg(X86::EAX).addReg(X86::EDX)
.addReg(X86::ESP);
break;
default:
visitInstruction(I);
}
// Emit a 'ret' instruction
BuildMI(BB, X86::RET, 0);
}
// getBlockAfter - Return the basic block which occurs lexically after the
// specified one.
static inline BasicBlock *getBlockAfter(BasicBlock *BB) {
Function::iterator I = BB; ++I; // Get iterator to next block
return I != BB->getParent()->end() ? &*I : 0;
}
/// visitBranchInst - Handle conditional and unconditional branches here. Note
/// that since code layout is frozen at this point, that if we are trying to
/// jump to a block that is the immediate successor of the current block, we can
/// just make a fall-through (but we don't currently).
///
void ISel::visitBranchInst(BranchInst &BI) {
BasicBlock *NextBB = getBlockAfter(BI.getParent()); // BB after current one
if (!BI.isConditional()) { // Unconditional branch?
if (BI.getSuccessor(0) != NextBB)
BuildMI(BB, X86::JMP, 1).addPCDisp(BI.getSuccessor(0));
return;
}
// See if we can fold the setcc into the branch itself...
SetCondInst *SCI = canFoldSetCCIntoBranch(BI.getCondition());
if (SCI == 0) {
// Nope, cannot fold setcc into this branch. Emit a branch on a condition
// computed some other way...
unsigned condReg = getReg(BI.getCondition());
BuildMI(BB, X86::CMPri8, 2).addReg(condReg).addZImm(0);
if (BI.getSuccessor(1) == NextBB) {
if (BI.getSuccessor(0) != NextBB)
BuildMI(BB, X86::JNE, 1).addPCDisp(BI.getSuccessor(0));
} else {
BuildMI(BB, X86::JE, 1).addPCDisp(BI.getSuccessor(1));
if (BI.getSuccessor(0) != NextBB)
BuildMI(BB, X86::JMP, 1).addPCDisp(BI.getSuccessor(0));
}
return;
}
unsigned OpNum = getSetCCNumber(SCI->getOpcode());
MachineBasicBlock::iterator MII = BB->end();
OpNum = EmitComparison(OpNum, SCI->getOperand(0), SCI->getOperand(1), BB,MII);
const Type *CompTy = SCI->getOperand(0)->getType();
bool isSigned = CompTy->isSigned() && getClassB(CompTy) != cFP;
// LLVM -> X86 signed X86 unsigned
// ----- ---------- ------------
// seteq -> je je
// setne -> jne jne
// setlt -> jl jb
// setge -> jge jae
// setgt -> jg ja
// setle -> jle jbe
// ----
// js // Used by comparison with 0 optimization
// jns
static const unsigned OpcodeTab[2][8] = {
{ X86::JE, X86::JNE, X86::JB, X86::JAE, X86::JA, X86::JBE, 0, 0 },
{ X86::JE, X86::JNE, X86::JL, X86::JGE, X86::JG, X86::JLE,
X86::JS, X86::JNS },
};
if (BI.getSuccessor(0) != NextBB) {
BuildMI(BB, OpcodeTab[isSigned][OpNum], 1).addPCDisp(BI.getSuccessor(0));
if (BI.getSuccessor(1) != NextBB)
BuildMI(BB, X86::JMP, 1).addPCDisp(BI.getSuccessor(1));
} else {
// Change to the inverse condition...
if (BI.getSuccessor(1) != NextBB) {
OpNum ^= 1;
BuildMI(BB, OpcodeTab[isSigned][OpNum], 1).addPCDisp(BI.getSuccessor(1));
}
}
}
/// doCall - This emits an abstract call instruction, setting up the arguments
/// and the return value as appropriate. For the actual function call itself,
/// it inserts the specified CallMI instruction into the stream.
///
void ISel::doCall(const ValueRecord &Ret, MachineInstr *CallMI,
const std::vector<ValueRecord> &Args) {
// Count how many bytes are to be pushed on the stack...
unsigned NumBytes = 0;
if (!Args.empty()) {
for (unsigned i = 0, e = Args.size(); i != e; ++i)
switch (getClassB(Args[i].Ty)) {
case cByte: case cShort: case cInt:
NumBytes += 4; break;
case cLong:
NumBytes += 8; break;
case cFP:
NumBytes += Args[i].Ty == Type::FloatTy ? 4 : 8;
break;
default: assert(0 && "Unknown class!");
}
// Adjust the stack pointer for the new arguments...
BuildMI(BB, X86::ADJCALLSTACKDOWN, 1).addZImm(NumBytes);
// Arguments go on the stack in reverse order, as specified by the ABI.
unsigned ArgOffset = 0;
for (unsigned i = 0, e = Args.size(); i != e; ++i) {
unsigned ArgReg = Args[i].Val ? getReg(Args[i].Val) : Args[i].Reg;
switch (getClassB(Args[i].Ty)) {
case cByte:
case cShort: {
// Promote arg to 32 bits wide into a temporary register...
unsigned R = makeAnotherReg(Type::UIntTy);
promote32(R, Args[i]);
addRegOffset(BuildMI(BB, X86::MOVmr32, 5),
X86::ESP, ArgOffset).addReg(R);
break;
}
case cInt:
addRegOffset(BuildMI(BB, X86::MOVmr32, 5),
X86::ESP, ArgOffset).addReg(ArgReg);
break;
case cLong:
addRegOffset(BuildMI(BB, X86::MOVmr32, 5),
X86::ESP, ArgOffset).addReg(ArgReg);
addRegOffset(BuildMI(BB, X86::MOVmr32, 5),
X86::ESP, ArgOffset+4).addReg(ArgReg+1);
ArgOffset += 4; // 8 byte entry, not 4.
break;
case cFP:
if (Args[i].Ty == Type::FloatTy) {
addRegOffset(BuildMI(BB, X86::FSTr32, 5),
X86::ESP, ArgOffset).addReg(ArgReg);
} else {
assert(Args[i].Ty == Type::DoubleTy && "Unknown FP type!");
addRegOffset(BuildMI(BB, X86::FSTr64, 5),
X86::ESP, ArgOffset).addReg(ArgReg);
ArgOffset += 4; // 8 byte entry, not 4.
}
break;
default: assert(0 && "Unknown class!");
}
ArgOffset += 4;
}
} else {
BuildMI(BB, X86::ADJCALLSTACKDOWN, 1).addZImm(0);
}
BB->push_back(CallMI);
BuildMI(BB, X86::ADJCALLSTACKUP, 1).addZImm(NumBytes);
// If there is a return value, scavenge the result from the location the call
// leaves it in...
//
if (Ret.Ty != Type::VoidTy) {
unsigned DestClass = getClassB(Ret.Ty);
switch (DestClass) {
case cByte:
case cShort:
case cInt: {
// Integral results are in %eax, or the appropriate portion
// thereof.
static const unsigned regRegMove[] = {
X86::MOVrr8, X86::MOVrr16, X86::MOVrr32
};
static const unsigned AReg[] = { X86::AL, X86::AX, X86::EAX };
BuildMI(BB, regRegMove[DestClass], 1, Ret.Reg).addReg(AReg[DestClass]);
break;
}
case cFP: // Floating-point return values live in %ST(0)
BuildMI(BB, X86::FpGETRESULT, 1, Ret.Reg);
break;
case cLong: // Long values are left in EDX:EAX
BuildMI(BB, X86::MOVrr32, 1, Ret.Reg).addReg(X86::EAX);
BuildMI(BB, X86::MOVrr32, 1, Ret.Reg+1).addReg(X86::EDX);
break;
default: assert(0 && "Unknown class!");
}
}
}
/// visitCallInst - Push args on stack and do a procedure call instruction.
void ISel::visitCallInst(CallInst &CI) {
MachineInstr *TheCall;
if (Function *F = CI.getCalledFunction()) {
// Is it an intrinsic function call?
if (Intrinsic::ID ID = (Intrinsic::ID)F->getIntrinsicID()) {
visitIntrinsicCall(ID, CI); // Special intrinsics are not handled here
return;
}
// Emit a CALL instruction with PC-relative displacement.
TheCall = BuildMI(X86::CALLpcrel32, 1).addGlobalAddress(F, true);
} else { // Emit an indirect call...
unsigned Reg = getReg(CI.getCalledValue());
TheCall = BuildMI(X86::CALLr32, 1).addReg(Reg);
}
std::vector<ValueRecord> Args;
for (unsigned i = 1, e = CI.getNumOperands(); i != e; ++i)
Args.push_back(ValueRecord(CI.getOperand(i)));
unsigned DestReg = CI.getType() != Type::VoidTy ? getReg(CI) : 0;
doCall(ValueRecord(DestReg, CI.getType()), TheCall, Args);
}
/// LowerUnknownIntrinsicFunctionCalls - This performs a prepass over the
/// function, lowering any calls to unknown intrinsic functions into the
/// equivalent LLVM code.
void ISel::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:
case Intrinsic::va_start:
case Intrinsic::va_copy:
case Intrinsic::va_end:
case Intrinsic::returnaddress:
case Intrinsic::frameaddress:
case Intrinsic::memcpy:
case Intrinsic::memset:
// We directly implement these intrinsics
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 ISel::visitIntrinsicCall(Intrinsic::ID ID, CallInst &CI) {
unsigned TmpReg1, TmpReg2;
switch (ID) {
case Intrinsic::va_start:
// Get the address of the first vararg value...
TmpReg1 = getReg(CI);
addFrameReference(BuildMI(BB, X86::LEAr32, 5, TmpReg1), VarArgsFrameIndex);
return;
case Intrinsic::va_copy:
TmpReg1 = getReg(CI);
TmpReg2 = getReg(CI.getOperand(1));
BuildMI(BB, X86::MOVrr32, 1, TmpReg1).addReg(TmpReg2);
return;
case Intrinsic::va_end: return; // Noop on X86
case Intrinsic::returnaddress:
case Intrinsic::frameaddress:
TmpReg1 = getReg(CI);
if (cast<Constant>(CI.getOperand(1))->isNullValue()) {
if (ID == Intrinsic::returnaddress) {
// Just load the return address
addFrameReference(BuildMI(BB, X86::MOVrm32, 4, TmpReg1),
ReturnAddressIndex);
} else {
addFrameReference(BuildMI(BB, X86::LEAr32, 4, TmpReg1),
ReturnAddressIndex, -4);
}
} else {
// Values other than zero are not implemented yet.
BuildMI(BB, X86::MOVri32, 1, TmpReg1).addZImm(0);
}
return;
case Intrinsic::memcpy: {
assert(CI.getNumOperands() == 5 && "Illegal llvm.memcpy call!");
unsigned Align = 1;
if (ConstantInt *AlignC = dyn_cast<ConstantInt>(CI.getOperand(4))) {
Align = AlignC->getRawValue();
if (Align == 0) Align = 1;
}
// Turn the byte code into # iterations
unsigned CountReg;
unsigned Opcode;
switch (Align & 3) {
case 2: // WORD aligned
if (ConstantInt *I = dyn_cast<ConstantInt>(CI.getOperand(3))) {
CountReg = getReg(ConstantUInt::get(Type::UIntTy, I->getRawValue()/2));
} else {
CountReg = makeAnotherReg(Type::IntTy);
unsigned ByteReg = getReg(CI.getOperand(3));
BuildMI(BB, X86::SHRri32, 2, CountReg).addReg(ByteReg).addZImm(1);
}
Opcode = X86::REP_MOVSW;
break;
case 0: // DWORD aligned
if (ConstantInt *I = dyn_cast<ConstantInt>(CI.getOperand(3))) {
CountReg = getReg(ConstantUInt::get(Type::UIntTy, I->getRawValue()/4));
} else {
CountReg = makeAnotherReg(Type::IntTy);
unsigned ByteReg = getReg(CI.getOperand(3));
BuildMI(BB, X86::SHRri32, 2, CountReg).addReg(ByteReg).addZImm(2);
}
Opcode = X86::REP_MOVSD;
break;
default: // BYTE aligned
CountReg = getReg(CI.getOperand(3));
Opcode = X86::REP_MOVSB;
break;
}
// No matter what the alignment is, we put the source in ESI, the
// destination in EDI, and the count in ECX.
TmpReg1 = getReg(CI.getOperand(1));
TmpReg2 = getReg(CI.getOperand(2));
BuildMI(BB, X86::MOVrr32, 1, X86::ECX).addReg(CountReg);
BuildMI(BB, X86::MOVrr32, 1, X86::EDI).addReg(TmpReg1);
BuildMI(BB, X86::MOVrr32, 1, X86::ESI).addReg(TmpReg2);
BuildMI(BB, Opcode, 0);
return;
}
case Intrinsic::memset: {
assert(CI.getNumOperands() == 5 && "Illegal llvm.memset call!");
unsigned Align = 1;
if (ConstantInt *AlignC = dyn_cast<ConstantInt>(CI.getOperand(4))) {
Align = AlignC->getRawValue();
if (Align == 0) Align = 1;
}
// Turn the byte code into # iterations
unsigned CountReg;
unsigned Opcode;
if (ConstantInt *ValC = dyn_cast<ConstantInt>(CI.getOperand(2))) {
unsigned Val = ValC->getRawValue() & 255;
// If the value is a constant, then we can potentially use larger copies.
switch (Align & 3) {
case 2: // WORD aligned
if (ConstantInt *I = dyn_cast<ConstantInt>(CI.getOperand(3))) {
CountReg =getReg(ConstantUInt::get(Type::UIntTy, I->getRawValue()/2));
} else {
CountReg = makeAnotherReg(Type::IntTy);
unsigned ByteReg = getReg(CI.getOperand(3));
BuildMI(BB, X86::SHRri32, 2, CountReg).addReg(ByteReg).addZImm(1);
}
BuildMI(BB, X86::MOVri16, 1, X86::AX).addZImm((Val << 8) | Val);
Opcode = X86::REP_STOSW;
break;
case 0: // DWORD aligned
if (ConstantInt *I = dyn_cast<ConstantInt>(CI.getOperand(3))) {
CountReg =getReg(ConstantUInt::get(Type::UIntTy, I->getRawValue()/4));
} else {
CountReg = makeAnotherReg(Type::IntTy);
unsigned ByteReg = getReg(CI.getOperand(3));
BuildMI(BB, X86::SHRri32, 2, CountReg).addReg(ByteReg).addZImm(2);
}
Val = (Val << 8) | Val;
BuildMI(BB, X86::MOVri32, 1, X86::EAX).addZImm((Val << 16) | Val);
Opcode = X86::REP_STOSD;
break;
default: // BYTE aligned
CountReg = getReg(CI.getOperand(3));
BuildMI(BB, X86::MOVri8, 1, X86::AL).addZImm(Val);
Opcode = X86::REP_STOSB;
break;
}
} else {
// If it's not a constant value we are storing, just fall back. We could
// try to be clever to form 16 bit and 32 bit values, but we don't yet.
unsigned ValReg = getReg(CI.getOperand(2));
BuildMI(BB, X86::MOVrr8, 1, X86::AL).addReg(ValReg);
CountReg = getReg(CI.getOperand(3));
Opcode = X86::REP_STOSB;
}
// No matter what the alignment is, we put the source in ESI, the
// destination in EDI, and the count in ECX.
TmpReg1 = getReg(CI.getOperand(1));
//TmpReg2 = getReg(CI.getOperand(2));
BuildMI(BB, X86::MOVrr32, 1, X86::ECX).addReg(CountReg);
BuildMI(BB, X86::MOVrr32, 1, X86::EDI).addReg(TmpReg1);
BuildMI(BB, Opcode, 0);
return;
}
default: assert(0 && "Error: unknown intrinsics should have been lowered!");
}
}
/// visitSimpleBinary - Implement simple binary operators for integral types...
/// OperatorClass is one of: 0 for Add, 1 for Sub, 2 for And, 3 for Or, 4 for
/// Xor.
void ISel::visitSimpleBinary(BinaryOperator &B, unsigned OperatorClass) {
unsigned DestReg = getReg(B);
MachineBasicBlock::iterator MI = BB->end();
emitSimpleBinaryOperation(BB, MI, B.getOperand(0), B.getOperand(1),
OperatorClass, DestReg);
}
/// emitSimpleBinaryOperation - Implement simple binary operators for integral
/// types... OperatorClass is one of: 0 for Add, 1 for Sub, 2 for And, 3 for
/// Or, 4 for Xor.
///
/// emitSimpleBinaryOperation - Common code shared between visitSimpleBinary
/// and constant expression support.
///
void ISel::emitSimpleBinaryOperation(MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
Value *Op0, Value *Op1,
unsigned OperatorClass, unsigned DestReg) {
unsigned Class = getClassB(Op0->getType());
// sub 0, X -> neg X
if (OperatorClass == 1 && Class != cLong)
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op0)) {
if (CI->isNullValue()) {
unsigned op1Reg = getReg(Op1, MBB, IP);
switch (Class) {
default: assert(0 && "Unknown class for this function!");
case cByte:
BMI(MBB, IP, X86::NEGr8, 1, DestReg).addReg(op1Reg);
return;
case cShort:
BMI(MBB, IP, X86::NEGr16, 1, DestReg).addReg(op1Reg);
return;
case cInt:
BMI(MBB, IP, X86::NEGr32, 1, DestReg).addReg(op1Reg);
return;
}
}
} else if (ConstantFP *CFP = dyn_cast<ConstantFP>(Op0))
if (CFP->isExactlyValue(-0.0)) {
// -0.0 - X === -X
unsigned op1Reg = getReg(Op1, MBB, IP);
BMI(MBB, IP, X86::FCHS, 1, DestReg).addReg(op1Reg);
return;
}
if (!isa<ConstantInt>(Op1) || Class == cLong) {
static const unsigned OpcodeTab[][4] = {
// Arithmetic operators
{ X86::ADDrr8, X86::ADDrr16, X86::ADDrr32, X86::FpADD }, // ADD
{ X86::SUBrr8, X86::SUBrr16, X86::SUBrr32, X86::FpSUB }, // SUB
// Bitwise operators
{ X86::ANDrr8, X86::ANDrr16, X86::ANDrr32, 0 }, // AND
{ X86:: ORrr8, X86:: ORrr16, X86:: ORrr32, 0 }, // OR
{ X86::XORrr8, X86::XORrr16, X86::XORrr32, 0 }, // XOR
};
bool isLong = false;
if (Class == cLong) {
isLong = true;
Class = cInt; // Bottom 32 bits are handled just like ints
}
unsigned Opcode = OpcodeTab[OperatorClass][Class];
assert(Opcode && "Floating point arguments to logical inst?");
unsigned Op0r = getReg(Op0, MBB, IP);
unsigned Op1r = getReg(Op1, MBB, IP);
BMI(MBB, IP, Opcode, 2, DestReg).addReg(Op0r).addReg(Op1r);
if (isLong) { // Handle the upper 32 bits of long values...
static const unsigned TopTab[] = {
X86::ADCrr32, X86::SBBrr32, X86::ANDrr32, X86::ORrr32, X86::XORrr32
};
BMI(MBB, IP, TopTab[OperatorClass], 2,
DestReg+1).addReg(Op0r+1).addReg(Op1r+1);
}
return;
}
// Special case: op Reg, <const>
ConstantInt *Op1C = cast<ConstantInt>(Op1);
unsigned Op0r = getReg(Op0, MBB, IP);
// xor X, -1 -> not X
if (OperatorClass == 4 && Op1C->isAllOnesValue()) {
static unsigned const NOTTab[] = { X86::NOTr8, X86::NOTr16, X86::NOTr32 };
BMI(MBB, IP, NOTTab[Class], 1, DestReg).addReg(Op0r);
return;
}
// add X, -1 -> dec X
if (OperatorClass == 0 && Op1C->isAllOnesValue()) {
static unsigned const DECTab[] = { X86::DECr8, X86::DECr16, X86::DECr32 };
BMI(MBB, IP, DECTab[Class], 1, DestReg).addReg(Op0r);
return;
}
// add X, 1 -> inc X
if (OperatorClass == 0 && Op1C->equalsInt(1)) {
static unsigned const DECTab[] = { X86::INCr8, X86::INCr16, X86::INCr32 };
BMI(MBB, IP, DECTab[Class], 1, DestReg).addReg(Op0r);
return;
}
static const unsigned OpcodeTab[][3] = {
// Arithmetic operators
{ X86::ADDri8, X86::ADDri16, X86::ADDri32 }, // ADD
{ X86::SUBri8, X86::SUBri16, X86::SUBri32 }, // SUB
// Bitwise operators
{ X86::ANDri8, X86::ANDri16, X86::ANDri32 }, // AND
{ X86:: ORri8, X86:: ORri16, X86:: ORri32 }, // OR
{ X86::XORri8, X86::XORri16, X86::XORri32 }, // XOR
};
assert(Class < 3 && "General code handles 64-bit integer types!");
unsigned Opcode = OpcodeTab[OperatorClass][Class];
uint64_t Op1v = cast<ConstantInt>(Op1C)->getRawValue();
// Mask off any upper bits of the constant, if there are any...
Op1v &= (1ULL << (8 << Class)) - 1;
BMI(MBB, IP, Opcode, 2, DestReg).addReg(Op0r).addZImm(Op1v);
}
/// doMultiply - Emit appropriate instructions to multiply together the
/// registers op0Reg and op1Reg, and put the result in DestReg. The type of the
/// result should be given as DestTy.
///
void ISel::doMultiply(MachineBasicBlock *MBB, MachineBasicBlock::iterator MBBI,
unsigned DestReg, const Type *DestTy,
unsigned op0Reg, unsigned op1Reg) {
unsigned Class = getClass(DestTy);
switch (Class) {
case cFP: // Floating point multiply
BMI(BB, MBBI, X86::FpMUL, 2, DestReg).addReg(op0Reg).addReg(op1Reg);
return;
case cInt:
case cShort:
BMI(BB, MBBI, Class == cInt ? X86::IMULrr32 : X86::IMULrr16, 2, DestReg)
.addReg(op0Reg).addReg(op1Reg);
return;
case cByte:
// Must use the MUL instruction, which forces use of AL...
BMI(MBB, MBBI, X86::MOVrr8, 1, X86::AL).addReg(op0Reg);
BMI(MBB, MBBI, X86::MULr8, 1).addReg(op1Reg);
BMI(MBB, MBBI, X86::MOVrr8, 1, DestReg).addReg(X86::AL);
return;
default:
case cLong: assert(0 && "doMultiply cannot operate on LONG values!");
}
}
// ExactLog2 - This function solves for (Val == 1 << (N-1)) and returns N. It
// returns zero when the input is not exactly a power of two.
static unsigned ExactLog2(unsigned Val) {
if (Val == 0) return 0;
unsigned Count = 0;
while (Val != 1) {
if (Val & 1) return 0;
Val >>= 1;
++Count;
}
return Count+1;
}
void ISel::doMultiplyConst(MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
unsigned DestReg, const Type *DestTy,
unsigned op0Reg, unsigned ConstRHS) {
unsigned Class = getClass(DestTy);
// If the element size is exactly a power of 2, use a shift to get it.
if (unsigned Shift = ExactLog2(ConstRHS)) {
switch (Class) {
default: assert(0 && "Unknown class for this function!");
case cByte:
BMI(MBB, IP, X86::SHLri32, 2, DestReg).addReg(op0Reg).addZImm(Shift-1);
return;
case cShort:
BMI(MBB, IP, X86::SHLri32, 2, DestReg).addReg(op0Reg).addZImm(Shift-1);
return;
case cInt:
BMI(MBB, IP, X86::SHLri32, 2, DestReg).addReg(op0Reg).addZImm(Shift-1);
return;
}
}
if (Class == cShort) {
BMI(MBB, IP, X86::IMULrri16, 2, DestReg).addReg(op0Reg).addZImm(ConstRHS);
return;
} else if (Class == cInt) {
BMI(MBB, IP, X86::IMULrri32, 2, DestReg).addReg(op0Reg).addZImm(ConstRHS);
return;
}
// Most general case, emit a normal multiply...
static const unsigned MOVriTab[] = {
X86::MOVri8, X86::MOVri16, X86::MOVri32
};
unsigned TmpReg = makeAnotherReg(DestTy);
BMI(MBB, IP, MOVriTab[Class], 1, TmpReg).addZImm(ConstRHS);
// Emit a MUL to multiply the register holding the index by
// elementSize, putting the result in OffsetReg.
doMultiply(MBB, IP, DestReg, DestTy, op0Reg, TmpReg);
}
/// visitMul - Multiplies are not simple binary operators because they must deal
/// with the EAX register explicitly.
///
void ISel::visitMul(BinaryOperator &I) {
unsigned Op0Reg = getReg(I.getOperand(0));
unsigned DestReg = getReg(I);
// Simple scalar multiply?
if (I.getType() != Type::LongTy && I.getType() != Type::ULongTy) {
if (ConstantInt *CI = dyn_cast<ConstantInt>(I.getOperand(1))) {
unsigned Val = (unsigned)CI->getRawValue(); // Cannot be 64-bit constant
MachineBasicBlock::iterator MBBI = BB->end();
doMultiplyConst(BB, MBBI, DestReg, I.getType(), Op0Reg, Val);
} else {
unsigned Op1Reg = getReg(I.getOperand(1));
MachineBasicBlock::iterator MBBI = BB->end();
doMultiply(BB, MBBI, DestReg, I.getType(), Op0Reg, Op1Reg);
}
} else {
unsigned Op1Reg = getReg(I.getOperand(1));
// Long value. We have to do things the hard way...
// Multiply the two low parts... capturing carry into EDX
BuildMI(BB, X86::MOVrr32, 1, X86::EAX).addReg(Op0Reg);
BuildMI(BB, X86::MULr32, 1).addReg(Op1Reg); // AL*BL
unsigned OverflowReg = makeAnotherReg(Type::UIntTy);
BuildMI(BB, X86::MOVrr32, 1, DestReg).addReg(X86::EAX); // AL*BL
BuildMI(BB, X86::MOVrr32, 1, OverflowReg).addReg(X86::EDX); // AL*BL >> 32
MachineBasicBlock::iterator MBBI = BB->end();
unsigned AHBLReg = makeAnotherReg(Type::UIntTy); // AH*BL
BMI(BB, MBBI, X86::IMULrr32, 2, AHBLReg).addReg(Op0Reg+1).addReg(Op1Reg);
unsigned AHBLplusOverflowReg = makeAnotherReg(Type::UIntTy);
BuildMI(BB, X86::ADDrr32, 2, // AH*BL+(AL*BL >> 32)
AHBLplusOverflowReg).addReg(AHBLReg).addReg(OverflowReg);
MBBI = BB->end();
unsigned ALBHReg = makeAnotherReg(Type::UIntTy); // AL*BH
BMI(BB, MBBI, X86::IMULrr32, 2, ALBHReg).addReg(Op0Reg).addReg(Op1Reg+1);
BuildMI(BB, X86::ADDrr32, 2, // AL*BH + AH*BL + (AL*BL >> 32)
DestReg+1).addReg(AHBLplusOverflowReg).addReg(ALBHReg);
}
}
/// visitDivRem - Handle division and remainder instructions... these
/// instruction both require the same instructions to be generated, they just
/// select the result from a different register. Note that both of these
/// instructions work differently for signed and unsigned operands.
///
void ISel::visitDivRem(BinaryOperator &I) {
unsigned Op0Reg = getReg(I.getOperand(0));
unsigned Op1Reg = getReg(I.getOperand(1));
unsigned ResultReg = getReg(I);
MachineBasicBlock::iterator IP = BB->end();
emitDivRemOperation(BB, IP, Op0Reg, Op1Reg, I.getOpcode() == Instruction::Div,
I.getType(), ResultReg);
}
void ISel::emitDivRemOperation(MachineBasicBlock *BB,
MachineBasicBlock::iterator IP,
unsigned Op0Reg, unsigned Op1Reg, bool isDiv,
const Type *Ty, unsigned ResultReg) {
unsigned Class = getClass(Ty);
switch (Class) {
case cFP: // Floating point divide
if (isDiv) {
BMI(BB, IP, X86::FpDIV, 2, ResultReg).addReg(Op0Reg).addReg(Op1Reg);
} else { // Floating point remainder...
MachineInstr *TheCall =
BuildMI(X86::CALLpcrel32, 1).addExternalSymbol("fmod", true);
std::vector<ValueRecord> Args;
Args.push_back(ValueRecord(Op0Reg, Type::DoubleTy));
Args.push_back(ValueRecord(Op1Reg, Type::DoubleTy));
doCall(ValueRecord(ResultReg, Type::DoubleTy), TheCall, Args);
}
return;
case cLong: {
static const char *FnName[] =
{ "__moddi3", "__divdi3", "__umoddi3", "__udivdi3" };
unsigned NameIdx = Ty->isUnsigned()*2 + isDiv;
MachineInstr *TheCall =
BuildMI(X86::CALLpcrel32, 1).addExternalSymbol(FnName[NameIdx], true);
std::vector<ValueRecord> Args;
Args.push_back(ValueRecord(Op0Reg, Type::LongTy));
Args.push_back(ValueRecord(Op1Reg, Type::LongTy));
doCall(ValueRecord(ResultReg, Type::LongTy), TheCall, Args);
return;
}
case cByte: case cShort: case cInt:
break; // Small integrals, handled below...
default: assert(0 && "Unknown class!");
}
static const unsigned Regs[] ={ X86::AL , X86::AX , X86::EAX };
static const unsigned MovOpcode[]={ X86::MOVrr8, X86::MOVrr16, X86::MOVrr32 };
static const unsigned SarOpcode[]={ X86::SARri8, X86::SARri16, X86::SARri32 };
static const unsigned ClrOpcode[]={ X86::MOVri8, X86::MOVri16, X86::MOVri32 };
static const unsigned ExtRegs[] ={ X86::AH , X86::DX , X86::EDX };
static const unsigned DivOpcode[][4] = {
{ X86::DIVr8 , X86::DIVr16 , X86::DIVr32 , 0 }, // Unsigned division
{ X86::IDIVr8, X86::IDIVr16, X86::IDIVr32, 0 }, // Signed division
};
bool isSigned = Ty->isSigned();
unsigned Reg = Regs[Class];
unsigned ExtReg = ExtRegs[Class];
// Put the first operand into one of the A registers...
BMI(BB, IP, MovOpcode[Class], 1, Reg).addReg(Op0Reg);
if (isSigned) {
// Emit a sign extension instruction...
unsigned ShiftResult = makeAnotherReg(Ty);
BMI(BB, IP, SarOpcode[Class], 2, ShiftResult).addReg(Op0Reg).addZImm(31);
BMI(BB, IP, MovOpcode[Class], 1, ExtReg).addReg(ShiftResult);
} else {
// If unsigned, emit a zeroing instruction... (reg = 0)
BMI(BB, IP, ClrOpcode[Class], 2, ExtReg).addZImm(0);
}
// Emit the appropriate divide or remainder instruction...
BMI(BB, IP, DivOpcode[isSigned][Class], 1).addReg(Op1Reg);
// Figure out which register we want to pick the result out of...
unsigned DestReg = isDiv ? Reg : ExtReg;
// Put the result into the destination register...
BMI(BB, IP, MovOpcode[Class], 1, ResultReg).addReg(DestReg);
}
/// Shift instructions: 'shl', 'sar', 'shr' - Some special cases here
/// for constant immediate shift values, and for constant immediate
/// shift values equal to 1. Even the general case is sort of special,
/// because the shift amount has to be in CL, not just any old register.
///
void ISel::visitShiftInst(ShiftInst &I) {
MachineBasicBlock::iterator IP = BB->end ();
emitShiftOperation (BB, IP, I.getOperand (0), I.getOperand (1),
I.getOpcode () == Instruction::Shl, I.getType (),
getReg (I));
}
/// emitShiftOperation - Common code shared between visitShiftInst and
/// constant expression support.
void ISel::emitShiftOperation(MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
Value *Op, Value *ShiftAmount, bool isLeftShift,
const Type *ResultTy, unsigned DestReg) {
unsigned SrcReg = getReg (Op, MBB, IP);
bool isSigned = ResultTy->isSigned ();
unsigned Class = getClass (ResultTy);
static const unsigned ConstantOperand[][4] = {
{ X86::SHRri8, X86::SHRri16, X86::SHRri32, X86::SHRDrri32 }, // SHR
{ X86::SARri8, X86::SARri16, X86::SARri32, X86::SHRDrri32 }, // SAR
{ X86::SHLri8, X86::SHLri16, X86::SHLri32, X86::SHLDrri32 }, // SHL
{ X86::SHLri8, X86::SHLri16, X86::SHLri32, X86::SHLDrri32 }, // SAL = SHL
};
static const unsigned NonConstantOperand[][4] = {
{ X86::SHRrCL8, X86::SHRrCL16, X86::SHRrCL32 }, // SHR
{ X86::SARrCL8, X86::SARrCL16, X86::SARrCL32 }, // SAR
{ X86::SHLrCL8, X86::SHLrCL16, X86::SHLrCL32 }, // SHL
{ X86::SHLrCL8, X86::SHLrCL16, X86::SHLrCL32 }, // SAL = SHL
};
// Longs, as usual, are handled specially...
if (Class == cLong) {
// If we have a constant shift, we can generate much more efficient code
// than otherwise...
//
if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(ShiftAmount)) {
unsigned Amount = CUI->getValue();
if (Amount < 32) {
const unsigned *Opc = ConstantOperand[isLeftShift*2+isSigned];
if (isLeftShift) {
BMI(MBB, IP, Opc[3], 3,
DestReg+1).addReg(SrcReg+1).addReg(SrcReg).addZImm(Amount);
BMI(MBB, IP, Opc[2], 2, DestReg).addReg(SrcReg).addZImm(Amount);
} else {
BMI(MBB, IP, Opc[3], 3,
DestReg).addReg(SrcReg ).addReg(SrcReg+1).addZImm(Amount);
BMI(MBB, IP, Opc[2], 2, DestReg+1).addReg(SrcReg+1).addZImm(Amount);
}
} else { // Shifting more than 32 bits
Amount -= 32;
if (isLeftShift) {
BMI(MBB, IP, X86::SHLri32, 2,
DestReg + 1).addReg(SrcReg).addZImm(Amount);
BMI(MBB, IP, X86::MOVri32, 1,
DestReg).addZImm(0);
} else {
unsigned Opcode = isSigned ? X86::SARri32 : X86::SHRri32;
BMI(MBB, IP, Opcode, 2, DestReg).addReg(SrcReg+1).addZImm(Amount);
BMI(MBB, IP, X86::MOVri32, 1, DestReg+1).addZImm(0);
}
}
} else {
unsigned TmpReg = makeAnotherReg(Type::IntTy);
if (!isLeftShift && isSigned) {
// If this is a SHR of a Long, then we need to do funny sign extension
// stuff. TmpReg gets the value to use as the high-part if we are
// shifting more than 32 bits.
BMI(MBB, IP, X86::SARri32, 2, TmpReg).addReg(SrcReg).addZImm(31);
} else {
// Other shifts use a fixed zero value if the shift is more than 32
// bits.
BMI(MBB, IP, X86::MOVri32, 1, TmpReg).addZImm(0);
}
// Initialize CL with the shift amount...
unsigned ShiftAmountReg = getReg(ShiftAmount, MBB, IP);
BMI(MBB, IP, X86::MOVrr8, 1, X86::CL).addReg(ShiftAmountReg);
unsigned TmpReg2 = makeAnotherReg(Type::IntTy);
unsigned TmpReg3 = makeAnotherReg(Type::IntTy);
if (isLeftShift) {
// TmpReg2 = shld inHi, inLo
BMI(MBB, IP, X86::SHLDrrCL32,2,TmpReg2).addReg(SrcReg+1).addReg(SrcReg);
// TmpReg3 = shl inLo, CL
BMI(MBB, IP, X86::SHLrCL32, 1, TmpReg3).addReg(SrcReg);
// Set the flags to indicate whether the shift was by more than 32 bits.
BMI(MBB, IP, X86::TESTri8, 2).addReg(X86::CL).addZImm(32);
// DestHi = (>32) ? TmpReg3 : TmpReg2;
BMI(MBB, IP, X86::CMOVNErr32, 2,
DestReg+1).addReg(TmpReg2).addReg(TmpReg3);
// DestLo = (>32) ? TmpReg : TmpReg3;
BMI(MBB, IP, X86::CMOVNErr32, 2,
DestReg).addReg(TmpReg3).addReg(TmpReg);
} else {
// TmpReg2 = shrd inLo, inHi
BMI(MBB, IP, X86::SHRDrrCL32,2,TmpReg2).addReg(SrcReg).addReg(SrcReg+1);
// TmpReg3 = s[ah]r inHi, CL
BMI(MBB, IP, isSigned ? X86::SARrCL32 : X86::SHRrCL32, 1, TmpReg3)
.addReg(SrcReg+1);
// Set the flags to indicate whether the shift was by more than 32 bits.
BMI(MBB, IP, X86::TESTri8, 2).addReg(X86::CL).addZImm(32);
// DestLo = (>32) ? TmpReg3 : TmpReg2;
BMI(MBB, IP, X86::CMOVNErr32, 2,
DestReg).addReg(TmpReg2).addReg(TmpReg3);
// DestHi = (>32) ? TmpReg : TmpReg3;
BMI(MBB, IP, X86::CMOVNErr32, 2,
DestReg+1).addReg(TmpReg3).addReg(TmpReg);
}
}
return;
}
if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(ShiftAmount)) {
// The shift amount is constant, guaranteed to be a ubyte. Get its value.
assert(CUI->getType() == Type::UByteTy && "Shift amount not a ubyte?");
const unsigned *Opc = ConstantOperand[isLeftShift*2+isSigned];
BMI(MBB, IP, Opc[Class], 2,
DestReg).addReg(SrcReg).addZImm(CUI->getValue());
} else { // The shift amount is non-constant.
unsigned ShiftAmountReg = getReg (ShiftAmount, MBB, IP);
BMI(MBB, IP, X86::MOVrr8, 1, X86::CL).addReg(ShiftAmountReg);
const unsigned *Opc = NonConstantOperand[isLeftShift*2+isSigned];
BMI(MBB, IP, Opc[Class], 1, DestReg).addReg(SrcReg);
}
}
/// visitLoadInst - Implement LLVM load instructions in terms of the x86 'mov'
/// instruction. The load and store instructions are the only place where we
/// need to worry about the memory layout of the target machine.
///
void ISel::visitLoadInst(LoadInst &I) {
unsigned DestReg = getReg(I);
unsigned BaseReg = 0, Scale = 1, IndexReg = 0, Disp = 0;
Value *Addr = I.getOperand(0);
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Addr)) {
if (isGEPFoldable(BB, GEP->getOperand(0), GEP->op_begin()+1, GEP->op_end(),
BaseReg, Scale, IndexReg, Disp))
Addr = 0; // Address is consumed!
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
if (CE->getOpcode() == Instruction::GetElementPtr)
if (isGEPFoldable(BB, CE->getOperand(0), CE->op_begin()+1, CE->op_end(),
BaseReg, Scale, IndexReg, Disp))
Addr = 0;
}
if (Addr) {
// If it's not foldable, reset addr mode.
BaseReg = getReg(Addr);
Scale = 1; IndexReg = 0; Disp = 0;
}
unsigned Class = getClassB(I.getType());
if (Class == cLong) {
addFullAddress(BuildMI(BB, X86::MOVrm32, 4, DestReg),
BaseReg, Scale, IndexReg, Disp);
addFullAddress(BuildMI(BB, X86::MOVrm32, 4, DestReg+1),
BaseReg, Scale, IndexReg, Disp+4);
return;
}
static const unsigned Opcodes[] = {
X86::MOVrm8, X86::MOVrm16, X86::MOVrm32, X86::FLDr32
};
unsigned Opcode = Opcodes[Class];
if (I.getType() == Type::DoubleTy) Opcode = X86::FLDr64;
addFullAddress(BuildMI(BB, Opcode, 4, DestReg),
BaseReg, Scale, IndexReg, Disp);
}
/// visitStoreInst - Implement LLVM store instructions in terms of the x86 'mov'
/// instruction.
///
void ISel::visitStoreInst(StoreInst &I) {
unsigned BaseReg = 0, Scale = 1, IndexReg = 0, Disp = 0;
Value *Addr = I.getOperand(1);
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Addr)) {
if (isGEPFoldable(BB, GEP->getOperand(0), GEP->op_begin()+1, GEP->op_end(),
BaseReg, Scale, IndexReg, Disp))
Addr = 0; // Address is consumed!
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
if (CE->getOpcode() == Instruction::GetElementPtr)
if (isGEPFoldable(BB, CE->getOperand(0), CE->op_begin()+1, CE->op_end(),
BaseReg, Scale, IndexReg, Disp))
Addr = 0;
}
if (Addr) {
// If it's not foldable, reset addr mode.
BaseReg = getReg(Addr);
Scale = 1; IndexReg = 0; Disp = 0;
}
const Type *ValTy = I.getOperand(0)->getType();
unsigned Class = getClassB(ValTy);
if (ConstantInt *CI = dyn_cast<ConstantInt>(I.getOperand(0))) {
uint64_t Val = CI->getRawValue();
if (Class == cLong) {
addFullAddress(BuildMI(BB, X86::MOVmi32, 5),
BaseReg, Scale, IndexReg, Disp).addZImm(Val & ~0U);
addFullAddress(BuildMI(BB, X86::MOVmi32, 5),
BaseReg, Scale, IndexReg, Disp+4).addZImm(Val>>32);
} else {
static const unsigned Opcodes[] = {
X86::MOVmi8, X86::MOVmi16, X86::MOVmi32
};
unsigned Opcode = Opcodes[Class];
addFullAddress(BuildMI(BB, Opcode, 5),
BaseReg, Scale, IndexReg, Disp).addZImm(Val);
}
} else if (ConstantBool *CB = dyn_cast<ConstantBool>(I.getOperand(0))) {
addFullAddress(BuildMI(BB, X86::MOVmi8, 5),
BaseReg, Scale, IndexReg, Disp).addZImm(CB->getValue());
} else {
if (Class == cLong) {
unsigned ValReg = getReg(I.getOperand(0));
addFullAddress(BuildMI(BB, X86::MOVmr32, 5),
BaseReg, Scale, IndexReg, Disp).addReg(ValReg);
addFullAddress(BuildMI(BB, X86::MOVmr32, 5),
BaseReg, Scale, IndexReg, Disp+4).addReg(ValReg+1);
} else {
unsigned ValReg = getReg(I.getOperand(0));
static const unsigned Opcodes[] = {
X86::MOVmr8, X86::MOVmr16, X86::MOVmr32, X86::FSTr32
};
unsigned Opcode = Opcodes[Class];
if (ValTy == Type::DoubleTy) Opcode = X86::FSTr64;
addFullAddress(BuildMI(BB, Opcode, 1+4),
BaseReg, Scale, IndexReg, Disp).addReg(ValReg);
}
}
}
/// visitCastInst - Here we have various kinds of copying with or without
/// sign extension going on.
void ISel::visitCastInst(CastInst &CI) {
Value *Op = CI.getOperand(0);
// If this is a cast from a 32-bit integer to a Long type, and the only uses
// of the case are GEP instructions, then the cast does not need to be
// generated explicitly, it will be folded into the GEP.
if (CI.getType() == Type::LongTy &&
(Op->getType() == Type::IntTy || Op->getType() == Type::UIntTy)) {
bool AllUsesAreGEPs = true;
for (Value::use_iterator I = CI.use_begin(), E = CI.use_end(); I != E; ++I)
if (!isa<GetElementPtrInst>(*I)) {
AllUsesAreGEPs = false;
break;
}
// No need to codegen this cast if all users are getelementptr instrs...
if (AllUsesAreGEPs) return;
}
unsigned DestReg = getReg(CI);
MachineBasicBlock::iterator MI = BB->end();
emitCastOperation(BB, MI, Op, CI.getType(), DestReg);
}
/// emitCastOperation - Common code shared between visitCastInst and
/// constant expression cast support.
void ISel::emitCastOperation(MachineBasicBlock *BB,
MachineBasicBlock::iterator IP,
Value *Src, const Type *DestTy,
unsigned DestReg) {
unsigned SrcReg = getReg(Src, BB, IP);
const Type *SrcTy = Src->getType();
unsigned SrcClass = getClassB(SrcTy);
unsigned DestClass = getClassB(DestTy);
// Implement casts to bool by using compare on the operand followed by set if
// not zero on the result.
if (DestTy == Type::BoolTy) {
switch (SrcClass) {
case cByte:
BMI(BB, IP, X86::TESTrr8, 2).addReg(SrcReg).addReg(SrcReg);
break;
case cShort:
BMI(BB, IP, X86::TESTrr16, 2).addReg(SrcReg).addReg(SrcReg);
break;
case cInt:
BMI(BB, IP, X86::TESTrr32, 2).addReg(SrcReg).addReg(SrcReg);
break;
case cLong: {
unsigned TmpReg = makeAnotherReg(Type::IntTy);
BMI(BB, IP, X86::ORrr32, 2, TmpReg).addReg(SrcReg).addReg(SrcReg+1);
break;
}
case cFP:
BMI(BB, IP, X86::FTST, 1).addReg(SrcReg);
BMI(BB, IP, X86::FNSTSWr8, 0);
BMI(BB, IP, X86::SAHF, 1);
break;
}
// If the zero flag is not set, then the value is true, set the byte to
// true.
BMI(BB, IP, X86::SETNEr, 1, DestReg);
return;
}
static const unsigned RegRegMove[] = {
X86::MOVrr8, X86::MOVrr16, X86::MOVrr32, X86::FpMOV, X86::MOVrr32
};
// Implement casts between values of the same type class (as determined by
// getClass) by using a register-to-register move.
if (SrcClass == DestClass) {
if (SrcClass <= cInt || (SrcClass == cFP && SrcTy == DestTy)) {
BMI(BB, IP, RegRegMove[SrcClass], 1, DestReg).addReg(SrcReg);
} else if (SrcClass == cFP) {
if (SrcTy == Type::FloatTy) { // double -> float
assert(DestTy == Type::DoubleTy && "Unknown cFP member!");
BMI(BB, IP, X86::FpMOV, 1, DestReg).addReg(SrcReg);
} else { // float -> double
assert(SrcTy == Type::DoubleTy && DestTy == Type::FloatTy &&
"Unknown cFP member!");
// Truncate from double to float by storing to memory as short, then
// reading it back.
unsigned FltAlign = TM.getTargetData().getFloatAlignment();
int FrameIdx = F->getFrameInfo()->CreateStackObject(4, FltAlign);
addFrameReference(BMI(BB, IP, X86::FSTr32, 5), FrameIdx).addReg(SrcReg);
addFrameReference(BMI(BB, IP, X86::FLDr32, 5, DestReg), FrameIdx);
}
} else if (SrcClass == cLong) {
BMI(BB, IP, X86::MOVrr32, 1, DestReg).addReg(SrcReg);
BMI(BB, IP, X86::MOVrr32, 1, DestReg+1).addReg(SrcReg+1);
} else {
assert(0 && "Cannot handle this type of cast instruction!");
abort();
}
return;
}
// Handle cast of SMALLER int to LARGER int using a move with sign extension
// or zero extension, depending on whether the source type was signed.
if (SrcClass <= cInt && (DestClass <= cInt || DestClass == cLong) &&
SrcClass < DestClass) {
bool isLong = DestClass == cLong;
if (isLong) DestClass = cInt;
static const unsigned Opc[][4] = {
{ X86::MOVSXr16r8, X86::MOVSXr32r8, X86::MOVSXr32r16, X86::MOVrr32 }, // s
{ X86::MOVZXr16r8, X86::MOVZXr32r8, X86::MOVZXr32r16, X86::MOVrr32 } // u
};
bool isUnsigned = SrcTy->isUnsigned();
BMI(BB, IP, Opc[isUnsigned][SrcClass + DestClass - 1], 1,
DestReg).addReg(SrcReg);
if (isLong) { // Handle upper 32 bits as appropriate...
if (isUnsigned) // Zero out top bits...
BMI(BB, IP, X86::MOVri32, 1, DestReg+1).addZImm(0);
else // Sign extend bottom half...
BMI(BB, IP, X86::SARri32, 2, DestReg+1).addReg(DestReg).addZImm(31);
}
return;
}
// Special case long -> int ...
if (SrcClass == cLong && DestClass == cInt) {
BMI(BB, IP, X86::MOVrr32, 1, DestReg).addReg(SrcReg);
return;
}
// Handle cast of LARGER int to SMALLER int using a move to EAX followed by a
// move out of AX or AL.
if ((SrcClass <= cInt || SrcClass == cLong) && DestClass <= cInt
&& SrcClass > DestClass) {
static const unsigned AReg[] = { X86::AL, X86::AX, X86::EAX, 0, X86::EAX };
BMI(BB, IP, RegRegMove[SrcClass], 1, AReg[SrcClass]).addReg(SrcReg);
BMI(BB, IP, RegRegMove[DestClass], 1, DestReg).addReg(AReg[DestClass]);
return;
}
// Handle casts from integer to floating point now...
if (DestClass == cFP) {
// Promote the integer to a type supported by FLD. We do this because there
// are no unsigned FLD instructions, so we must promote an unsigned value to
// a larger signed value, then use FLD on the larger value.
//
const Type *PromoteType = 0;
unsigned PromoteOpcode;
unsigned RealDestReg = DestReg;
switch (SrcTy->getPrimitiveID()) {
case Type::BoolTyID:
case Type::SByteTyID:
// We don't have the facilities for directly loading byte sized data from
// memory (even signed). Promote it to 16 bits.
PromoteType = Type::ShortTy;
PromoteOpcode = X86::MOVSXr16r8;
break;
case Type::UByteTyID:
PromoteType = Type::ShortTy;
PromoteOpcode = X86::MOVZXr16r8;
break;
case Type::UShortTyID:
PromoteType = Type::IntTy;
PromoteOpcode = X86::MOVZXr32r16;
break;
case Type::UIntTyID: {
// Make a 64 bit temporary... and zero out the top of it...
unsigned TmpReg = makeAnotherReg(Type::LongTy);
BMI(BB, IP, X86::MOVrr32, 1, TmpReg).addReg(SrcReg);
BMI(BB, IP, X86::MOVri32, 1, TmpReg+1).addZImm(0);
SrcTy = Type::LongTy;
SrcClass = cLong;
SrcReg = TmpReg;
break;
}
case Type::ULongTyID:
// Don't fild into the read destination.
DestReg = makeAnotherReg(Type::DoubleTy);
break;
default: // No promotion needed...
break;
}
if (PromoteType) {
unsigned TmpReg = makeAnotherReg(PromoteType);
unsigned Opc = SrcTy->isSigned() ? X86::MOVSXr16r8 : X86::MOVZXr16r8;
BMI(BB, IP, Opc, 1, TmpReg).addReg(SrcReg);
SrcTy = PromoteType;
SrcClass = getClass(PromoteType);
SrcReg = TmpReg;
}
// Spill the integer to memory and reload it from there...
int FrameIdx =
F->getFrameInfo()->CreateStackObject(SrcTy, TM.getTargetData());
if (SrcClass == cLong) {
addFrameReference(BMI(BB, IP, X86::MOVmr32, 5), FrameIdx).addReg(SrcReg);
addFrameReference(BMI(BB, IP, X86::MOVmr32, 5),
FrameIdx, 4).addReg(SrcReg+1);
} else {
static const unsigned Op1[] = { X86::MOVmr8, X86::MOVmr16, X86::MOVmr32 };
addFrameReference(BMI(BB, IP, Op1[SrcClass], 5), FrameIdx).addReg(SrcReg);
}
static const unsigned Op2[] =
{ 0/*byte*/, X86::FILDr16, X86::FILDr32, 0/*FP*/, X86::FILDr64 };
addFrameReference(BMI(BB, IP, Op2[SrcClass], 5, DestReg), FrameIdx);
// We need special handling for unsigned 64-bit integer sources. If the
// input number has the "sign bit" set, then we loaded it incorrectly as a
// negative 64-bit number. In this case, add an offset value.
if (SrcTy == Type::ULongTy) {
// Emit a test instruction to see if the dynamic input value was signed.
BMI(BB, IP, X86::TESTrr32, 2).addReg(SrcReg+1).addReg(SrcReg+1);
// If the sign bit is set, get a pointer to an offset, otherwise get a
// pointer to a zero.
MachineConstantPool *CP = F->getConstantPool();
unsigned Zero = makeAnotherReg(Type::IntTy);
Constant *Null = Constant::getNullValue(Type::UIntTy);
addConstantPoolReference(BMI(BB, IP, X86::LEAr32, 5, Zero),
CP->getConstantPoolIndex(Null));
unsigned Offset = makeAnotherReg(Type::IntTy);
Constant *OffsetCst = ConstantUInt::get(Type::UIntTy, 0x5f800000);
addConstantPoolReference(BMI(BB, IP, X86::LEAr32, 5, Offset),
CP->getConstantPoolIndex(OffsetCst));
unsigned Addr = makeAnotherReg(Type::IntTy);
BMI(BB, IP, X86::CMOVSrr32, 2, Addr).addReg(Zero).addReg(Offset);
// Load the constant for an add. FIXME: this could make an 'fadd' that
// reads directly from memory, but we don't support these yet.
unsigned ConstReg = makeAnotherReg(Type::DoubleTy);
addDirectMem(BMI(BB, IP, X86::FLDr32, 4, ConstReg), Addr);
BMI(BB, IP, X86::FpADD, 2, RealDestReg).addReg(ConstReg).addReg(DestReg);
}
return;
}
// Handle casts from floating point to integer now...
if (SrcClass == cFP) {
// Change the floating point control register to use "round towards zero"
// mode when truncating to an integer value.
//
int CWFrameIdx = F->getFrameInfo()->CreateStackObject(2, 2);
addFrameReference(BMI(BB, IP, X86::FNSTCWm16, 4), CWFrameIdx);
// Load the old value of the high byte of the control word...
unsigned HighPartOfCW = makeAnotherReg(Type::UByteTy);
addFrameReference(BMI(BB, IP, X86::MOVrm8, 4, HighPartOfCW), CWFrameIdx, 1);
// Set the high part to be round to zero...
addFrameReference(BMI(BB, IP, X86::MOVmi8, 5), CWFrameIdx, 1).addZImm(12);
// Reload the modified control word now...
addFrameReference(BMI(BB, IP, X86::FLDCWm16, 4), CWFrameIdx);
// Restore the memory image of control word to original value
addFrameReference(BMI(BB, IP, X86::MOVmr8, 5),
CWFrameIdx, 1).addReg(HighPartOfCW);
// We don't have the facilities for directly storing byte sized data to
// memory. Promote it to 16 bits. We also must promote unsigned values to
// larger classes because we only have signed FP stores.
unsigned StoreClass = DestClass;
const Type *StoreTy = DestTy;
if (StoreClass == cByte || DestTy->isUnsigned())
switch (StoreClass) {
case cByte: StoreTy = Type::ShortTy; StoreClass = cShort; break;
case cShort: StoreTy = Type::IntTy; StoreClass = cInt; break;
case cInt: StoreTy = Type::LongTy; StoreClass = cLong; break;
// The following treatment of cLong may not be perfectly right,
// but it survives chains of casts of the form
// double->ulong->double.
case cLong: StoreTy = Type::LongTy; StoreClass = cLong; break;
default: assert(0 && "Unknown store class!");
}
// Spill the integer to memory and reload it from there...
int FrameIdx =
F->getFrameInfo()->CreateStackObject(StoreTy, TM.getTargetData());
static const unsigned Op1[] =
{ 0, X86::FISTr16, X86::FISTr32, 0, X86::FISTPr64 };
addFrameReference(BMI(BB, IP, Op1[StoreClass], 5), FrameIdx).addReg(SrcReg);
if (DestClass == cLong) {
addFrameReference(BMI(BB, IP, X86::MOVrm32, 4, DestReg), FrameIdx);
addFrameReference(BMI(BB, IP, X86::MOVrm32, 4, DestReg+1), FrameIdx, 4);
} else {
static const unsigned Op2[] = { X86::MOVrm8, X86::MOVrm16, X86::MOVrm32 };
addFrameReference(BMI(BB, IP, Op2[DestClass], 4, DestReg), FrameIdx);
}
// Reload the original control word now...
addFrameReference(BMI(BB, IP, X86::FLDCWm16, 4), CWFrameIdx);
return;
}
// Anything we haven't handled already, we can't (yet) handle at all.
assert(0 && "Unhandled cast instruction!");
abort();
}
/// visitVANextInst - Implement the va_next instruction...
///
void ISel::visitVANextInst(VANextInst &I) {
unsigned VAList = getReg(I.getOperand(0));
unsigned DestReg = getReg(I);
unsigned Size;
switch (I.getArgType()->getPrimitiveID()) {
default:
std::cerr << I;
assert(0 && "Error: bad type for va_next instruction!");
return;
case Type::PointerTyID:
case Type::UIntTyID:
case Type::IntTyID:
Size = 4;
break;
case Type::ULongTyID:
case Type::LongTyID:
case Type::DoubleTyID:
Size = 8;
break;
}
// Increment the VAList pointer...
BuildMI(BB, X86::ADDri32, 2, DestReg).addReg(VAList).addZImm(Size);
}
void ISel::visitVAArgInst(VAArgInst &I) {
unsigned VAList = getReg(I.getOperand(0));
unsigned DestReg = getReg(I);
switch (I.getType()->getPrimitiveID()) {
default:
std::cerr << I;
assert(0 && "Error: bad type for va_next instruction!");
return;
case Type::PointerTyID:
case Type::UIntTyID:
case Type::IntTyID:
addDirectMem(BuildMI(BB, X86::MOVrm32, 4, DestReg), VAList);
break;
case Type::ULongTyID:
case Type::LongTyID:
addDirectMem(BuildMI(BB, X86::MOVrm32, 4, DestReg), VAList);
addRegOffset(BuildMI(BB, X86::MOVrm32, 4, DestReg+1), VAList, 4);
break;
case Type::DoubleTyID:
addDirectMem(BuildMI(BB, X86::FLDr64, 4, DestReg), VAList);
break;
}
}
void ISel::visitGetElementPtrInst(GetElementPtrInst &I) {
// If this GEP instruction will be folded into all of its users, we don't need
// to explicitly calculate it!
unsigned A, B, C, D;
if (isGEPFoldable(0, I.getOperand(0), I.op_begin()+1, I.op_end(), A,B,C,D)) {
// Check all of the users of the instruction to see if they are loads and
// stores.
bool AllWillFold = true;
for (Value::use_iterator UI = I.use_begin(), E = I.use_end(); UI != E; ++UI)
if (cast<Instruction>(*UI)->getOpcode() != Instruction::Load)
if (cast<Instruction>(*UI)->getOpcode() != Instruction::Store ||
cast<Instruction>(*UI)->getOperand(0) == &I) {
AllWillFold = false;
break;
}
// If the instruction is foldable, and will be folded into all users, don't
// emit it!
if (AllWillFold) return;
}
unsigned outputReg = getReg(I);
emitGEPOperation(BB, BB->end(), I.getOperand(0),
I.op_begin()+1, I.op_end(), outputReg);
}
/// getGEPIndex - Inspect the getelementptr operands specified with GEPOps and
/// GEPTypes (the derived types being stepped through at each level). On return
/// from this function, if some indexes of the instruction are representable as
/// an X86 lea instruction, the machine operands are put into the Ops
/// instruction and the consumed indexes are poped from the GEPOps/GEPTypes
/// lists. Otherwise, GEPOps.size() is returned. If this returns a an
/// addressing mode that only partially consumes the input, the BaseReg input of
/// the addressing mode must be left free.
///
/// Note that there is one fewer entry in GEPTypes than there is in GEPOps.
///
void ISel::getGEPIndex(MachineBasicBlock *MBB, MachineBasicBlock::iterator IP,
std::vector<Value*> &GEPOps,
std::vector<const Type*> &GEPTypes, unsigned &BaseReg,
unsigned &Scale, unsigned &IndexReg, unsigned &Disp) {
const TargetData &TD = TM.getTargetData();
// Clear out the state we are working with...
BaseReg = 0; // No base register
Scale = 1; // Unit scale
IndexReg = 0; // No index register
Disp = 0; // No displacement
// While there are GEP indexes that can be folded into the current address,
// keep processing them.
while (!GEPTypes.empty()) {
if (const StructType *StTy = dyn_cast<StructType>(GEPTypes.back())) {
// It's a struct access. CUI is the index into the structure,
// which names the field. This index must have unsigned type.
const ConstantUInt *CUI = cast<ConstantUInt>(GEPOps.back());
// Use the TargetData structure to pick out what the layout of the
// structure is in memory. Since the structure index must be constant, we
// can get its value and use it to find the right byte offset from the
// StructLayout class's list of structure member offsets.
Disp += TD.getStructLayout(StTy)->MemberOffsets[CUI->getValue()];
GEPOps.pop_back(); // Consume a GEP operand
GEPTypes.pop_back();
} else {
// It's an array or pointer access: [ArraySize x ElementType].
const SequentialType *SqTy = cast<SequentialType>(GEPTypes.back());
Value *idx = GEPOps.back();
// idx is the index into the array. Unlike with structure
// indices, we may not know its actual value at code-generation
// time.
assert(idx->getType() == Type::LongTy && "Bad GEP array index!");
// If idx is a constant, fold it into the offset.
unsigned TypeSize = TD.getTypeSize(SqTy->getElementType());
if (ConstantSInt *CSI = dyn_cast<ConstantSInt>(idx)) {
Disp += TypeSize*CSI->getValue();
} else {
// If the index reg is already taken, we can't handle this index.
if (IndexReg) return;
// If this is a size that we can handle, then add the index as
switch (TypeSize) {
case 1: case 2: case 4: case 8:
// These are all acceptable scales on X86.
Scale = TypeSize;
break;
default:
// Otherwise, we can't handle this scale
return;
}
if (CastInst *CI = dyn_cast<CastInst>(idx))
if (CI->getOperand(0)->getType() == Type::IntTy ||
CI->getOperand(0)->getType() == Type::UIntTy)
idx = CI->getOperand(0);
IndexReg = MBB ? getReg(idx, MBB, IP) : 1;
}
GEPOps.pop_back(); // Consume a GEP operand
GEPTypes.pop_back();
}
}
// GEPTypes is empty, which means we have a single operand left. See if we
// can set it as the base register.
//
// FIXME: When addressing modes are more powerful/correct, we could load
// global addresses directly as 32-bit immediates.
assert(BaseReg == 0);
BaseReg = MBB ? getReg(GEPOps[0], MBB, IP) : 1;
GEPOps.pop_back(); // Consume the last GEP operand
}
/// isGEPFoldable - Return true if the specified GEP can be completely
/// folded into the addressing mode of a load/store or lea instruction.
bool ISel::isGEPFoldable(MachineBasicBlock *MBB,
Value *Src, User::op_iterator IdxBegin,
User::op_iterator IdxEnd, unsigned &BaseReg,
unsigned &Scale, unsigned &IndexReg, unsigned &Disp) {
if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Src))
Src = CPR->getValue();
std::vector<Value*> GEPOps;
GEPOps.resize(IdxEnd-IdxBegin+1);
GEPOps[0] = Src;
std::copy(IdxBegin, IdxEnd, GEPOps.begin()+1);
std::vector<const Type*> GEPTypes;
GEPTypes.assign(gep_type_begin(Src->getType(), IdxBegin, IdxEnd),
gep_type_end(Src->getType(), IdxBegin, IdxEnd));
MachineBasicBlock::iterator IP;
if (MBB) IP = MBB->end();
getGEPIndex(MBB, IP, GEPOps, GEPTypes, BaseReg, Scale, IndexReg, Disp);
// We can fold it away iff the getGEPIndex call eliminated all operands.
return GEPOps.empty();
}
void ISel::emitGEPOperation(MachineBasicBlock *MBB,
MachineBasicBlock::iterator IP,
Value *Src, User::op_iterator IdxBegin,
User::op_iterator IdxEnd, unsigned TargetReg) {
const TargetData &TD = TM.getTargetData();
if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Src))
Src = CPR->getValue();
std::vector<Value*> GEPOps;
GEPOps.resize(IdxEnd-IdxBegin+1);
GEPOps[0] = Src;
std::copy(IdxBegin, IdxEnd, GEPOps.begin()+1);
std::vector<const Type*> GEPTypes;
GEPTypes.assign(gep_type_begin(Src->getType(), IdxBegin, IdxEnd),
gep_type_end(Src->getType(), IdxBegin, IdxEnd));
// Keep emitting instructions until we consume the entire GEP instruction.
while (!GEPOps.empty()) {
unsigned OldSize = GEPOps.size();
unsigned BaseReg, Scale, IndexReg, Disp;
getGEPIndex(MBB, IP, GEPOps, GEPTypes, BaseReg, Scale, IndexReg, Disp);
if (GEPOps.size() != OldSize) {
// getGEPIndex consumed some of the input. Build an LEA instruction here.
unsigned NextTarget = 0;
if (!GEPOps.empty()) {
assert(BaseReg == 0 &&
"getGEPIndex should have left the base register open for chaining!");
NextTarget = BaseReg = makeAnotherReg(Type::UIntTy);
}
if (IndexReg == 0 && Disp == 0)
BMI(MBB, IP, X86::MOVrr32, 1, TargetReg).addReg(BaseReg);
else
addFullAddress(BMI(MBB, IP, X86::LEAr32, 5, TargetReg),
BaseReg, Scale, IndexReg, Disp);
--IP;
TargetReg = NextTarget;
} else if (GEPTypes.empty()) {
// The getGEPIndex operation didn't want to build an LEA. Check to see if
// all operands are consumed but the base pointer. If so, just load it
// into the register.
if (GlobalValue *GV = dyn_cast<GlobalValue>(GEPOps[0])) {
BMI(MBB, IP, X86::MOVri32, 1, TargetReg).addGlobalAddress(GV);
} else {
unsigned BaseReg = getReg(GEPOps[0], MBB, IP);
BMI(MBB, IP, X86::MOVrr32, 1, TargetReg).addReg(BaseReg);
}
break; // we are now done
} else {
// It's an array or pointer access: [ArraySize x ElementType].
const SequentialType *SqTy = cast<SequentialType>(GEPTypes.back());
Value *idx = GEPOps.back();
GEPOps.pop_back(); // Consume a GEP operand
GEPTypes.pop_back();
// idx is the index into the array. Unlike with structure
// indices, we may not know its actual value at code-generation
// time.
assert(idx->getType() == Type::LongTy && "Bad GEP array index!");
// Most GEP instructions use a [cast (int/uint) to LongTy] as their
// operand on X86. Handle this case directly now...
if (CastInst *CI = dyn_cast<CastInst>(idx))
if (CI->getOperand(0)->getType() == Type::IntTy ||
CI->getOperand(0)->getType() == Type::UIntTy)
idx = CI->getOperand(0);
// We want to add BaseReg 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).
const Type *ElTy = SqTy->getElementType();
unsigned elementSize = TD.getTypeSize(ElTy);
// If idxReg is a constant, we don't need to perform the multiply!
if (ConstantSInt *CSI = dyn_cast<ConstantSInt>(idx)) {
if (!CSI->isNullValue()) {
unsigned Offset = elementSize*CSI->getValue();
unsigned Reg = makeAnotherReg(Type::UIntTy);
BMI(MBB, IP, X86::ADDri32, 2, TargetReg).addReg(Reg).addZImm(Offset);
--IP; // Insert the next instruction before this one.
TargetReg = Reg; // Codegen the rest of the GEP into this
}
} else if (elementSize == 1) {
// If the element size is 1, we don't have to multiply, just add
unsigned idxReg = getReg(idx, MBB, IP);
unsigned Reg = makeAnotherReg(Type::UIntTy);
BMI(MBB, IP, X86::ADDrr32, 2, TargetReg).addReg(Reg).addReg(idxReg);
--IP; // Insert the next instruction before this one.
TargetReg = Reg; // Codegen the rest of the GEP into this
} else {
unsigned idxReg = getReg(idx, MBB, IP);
unsigned OffsetReg = makeAnotherReg(Type::UIntTy);
// Make sure we can back the iterator up to point to the first
// instruction emitted.
MachineBasicBlock::iterator BeforeIt = IP;
if (IP == MBB->begin())
BeforeIt = MBB->end();
else
--BeforeIt;
doMultiplyConst(MBB, IP, OffsetReg, Type::IntTy, idxReg, elementSize);
// Emit an ADD to add OffsetReg to the basePtr.
unsigned Reg = makeAnotherReg(Type::UIntTy);
BMI(MBB, IP, X86::ADDrr32, 2, TargetReg).addReg(Reg).addReg(OffsetReg);
// Step to the first instruction of the multiply.
if (BeforeIt == MBB->end())
IP = MBB->begin();
else
IP = ++BeforeIt;
TargetReg = Reg; // Codegen the rest of the GEP into this
}
}
}
}
/// visitAllocaInst - If this is a fixed size alloca, allocate space from the
/// frame manager, otherwise do it the hard way.
///
void ISel::visitAllocaInst(AllocaInst &I) {
// Find the data size of the alloca inst's getAllocatedType.
const Type *Ty = I.getAllocatedType();
unsigned TySize = TM.getTargetData().getTypeSize(Ty);
// If this is a fixed size alloca in the entry block for the function,
// statically stack allocate the space.
//
if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(I.getArraySize())) {
if (I.getParent() == I.getParent()->getParent()->begin()) {
TySize *= CUI->getValue(); // Get total allocated size...
unsigned Alignment = TM.getTargetData().getTypeAlignment(Ty);
// Create a new stack object using the frame manager...
int FrameIdx = F->getFrameInfo()->CreateStackObject(TySize, Alignment);
addFrameReference(BuildMI(BB, X86::LEAr32, 5, getReg(I)), FrameIdx);
return;
}
}
// Create a register to hold the temporary result of multiplying the type size
// constant by the variable amount.
unsigned TotalSizeReg = makeAnotherReg(Type::UIntTy);
unsigned SrcReg1 = getReg(I.getArraySize());
// TotalSizeReg = mul <numelements>, <TypeSize>
MachineBasicBlock::iterator MBBI = BB->end();
doMultiplyConst(BB, MBBI, TotalSizeReg, Type::UIntTy, SrcReg1, TySize);
// AddedSize = add <TotalSizeReg>, 15
unsigned AddedSizeReg = makeAnotherReg(Type::UIntTy);
BuildMI(BB, X86::ADDri32, 2, AddedSizeReg).addReg(TotalSizeReg).addZImm(15);
// AlignedSize = and <AddedSize>, ~15
unsigned AlignedSize = makeAnotherReg(Type::UIntTy);
BuildMI(BB, X86::ANDri32, 2, AlignedSize).addReg(AddedSizeReg).addZImm(~15);
// Subtract size from stack pointer, thereby allocating some space.
BuildMI(BB, X86::SUBrr32, 2, X86::ESP).addReg(X86::ESP).addReg(AlignedSize);
// Put a pointer to the space into the result register, by copying
// the stack pointer.
BuildMI(BB, X86::MOVrr32, 1, getReg(I)).addReg(X86::ESP);
// Inform the Frame Information that we have just allocated a variable-sized
// object.
F->getFrameInfo()->CreateVariableSizedObject();
}
/// visitMallocInst - Malloc instructions are code generated into direct calls
/// to the library malloc.
///
void ISel::visitMallocInst(MallocInst &I) {
unsigned AllocSize = TM.getTargetData().getTypeSize(I.getAllocatedType());
unsigned Arg;
if (ConstantUInt *C = dyn_cast<ConstantUInt>(I.getOperand(0))) {
Arg = getReg(ConstantUInt::get(Type::UIntTy, C->getValue() * AllocSize));
} else {
Arg = makeAnotherReg(Type::UIntTy);
unsigned Op0Reg = getReg(I.getOperand(0));
MachineBasicBlock::iterator MBBI = BB->end();
doMultiplyConst(BB, MBBI, Arg, Type::UIntTy, Op0Reg, AllocSize);
}
std::vector<ValueRecord> Args;
Args.push_back(ValueRecord(Arg, Type::UIntTy));
MachineInstr *TheCall = BuildMI(X86::CALLpcrel32,
1).addExternalSymbol("malloc", true);
doCall(ValueRecord(getReg(I), I.getType()), TheCall, Args);
}
/// visitFreeInst - Free instructions are code gen'd to call the free libc
/// function.
///
void ISel::visitFreeInst(FreeInst &I) {
std::vector<ValueRecord> Args;
Args.push_back(ValueRecord(I.getOperand(0)));
MachineInstr *TheCall = BuildMI(X86::CALLpcrel32,
1).addExternalSymbol("free", true);
doCall(ValueRecord(0, Type::VoidTy), TheCall, Args);
}
/// createX86SimpleInstructionSelector - This pass converts an LLVM function
/// into a machine code representation is a very simple peep-hole fashion. The
/// generated code sucks but the implementation is nice and simple.
///
FunctionPass *llvm::createX86SimpleInstructionSelector(TargetMachine &TM) {
return new ISel(TM);
}
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