#include "X86.h"
#include "X86InstrInfo.h"
+#include "X86InstrBuilder.h"
#include "llvm/Function.h"
#include "llvm/iTerminators.h"
+#include "llvm/iOperators.h"
+#include "llvm/iOther.h"
+#include "llvm/iPHINode.h"
+#include "llvm/iMemory.h"
#include "llvm/Type.h"
#include "llvm/Constants.h"
+#include "llvm/Pass.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/InstVisitor.h"
+#include "llvm/Target/MRegisterInfo.h"
#include <map>
+using namespace MOTy; // Get Use, Def, UseAndDef
+
namespace {
- struct ISel : public InstVisitor<ISel> { // eventually will be a FunctionPass
+ struct ISel : public FunctionPass, InstVisitor<ISel> {
+ TargetMachine &TM;
MachineFunction *F; // The function we are compiling into
MachineBasicBlock *BB; // The current MBB we are compiling
unsigned CurReg;
std::map<Value*, unsigned> RegMap; // Mapping between Val's and SSA Regs
- ISel(MachineFunction *f)
- : F(f), BB(0), CurReg(MRegisterInfo::FirstVirtualRegister) {}
+ ISel(TargetMachine &tm)
+ : TM(tm), F(0), BB(0), CurReg(MRegisterInfo::FirstVirtualRegister) {}
/// runOnFunction - Top level implementation of instruction selection for
/// the entire function.
///
- bool runOnFunction(Function &F) {
- visit(F);
+ bool runOnFunction(Function &Fn) {
+ F = &MachineFunction::construct(&Fn, TM);
+ visit(Fn);
RegMap.clear();
+ CurReg = MRegisterInfo::FirstVirtualRegister;
+ F = 0;
return false; // We never modify the LLVM itself.
}
/// instructions will be invoked for all instructions in the basic block.
///
void visitBasicBlock(BasicBlock &LLVM_BB) {
- BB = new MachineBasicBlock();
+ BB = new MachineBasicBlock(&LLVM_BB);
// FIXME: Use the auto-insert form when it's available
F->getBasicBlockList().push_back(BB);
}
// Visitation methods for various instructions. These methods simply emit
// fixed X86 code for each instruction.
//
+
+ // Control flow operators
void visitReturnInst(ReturnInst &RI);
- void visitAdd(BinaryOperator &B);
+ void visitBranchInst(BranchInst &BI);
+ void visitCallInst(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 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); }
+
+ // Binary comparison operators
+ void visitSetCCInst(SetCondInst &I, unsigned OpNum);
+ void visitSetEQ(SetCondInst &I) { visitSetCCInst(I, 0); }
+ void visitSetNE(SetCondInst &I) { visitSetCCInst(I, 1); }
+ void visitSetLT(SetCondInst &I) { visitSetCCInst(I, 2); }
+ void visitSetGT(SetCondInst &I) { visitSetCCInst(I, 3); }
+ void visitSetLE(SetCondInst &I) { visitSetCCInst(I, 4); }
+ void visitSetGE(SetCondInst &I) { visitSetCCInst(I, 5); }
+
+ // Memory Instructions
+ void visitLoadInst(LoadInst &I);
+ void visitStoreInst(StoreInst &I);
+
+ // Other operators
+ void visitShiftInst(ShiftInst &I);
+ void visitPHINode(PHINode &I);
+ void visitCastInst(CastInst &I);
void visitInstruction(Instruction &I) {
std::cerr << "Cannot instruction select: " << I;
abort();
}
+ void promote32 (const unsigned targetReg, Value *v);
/// copyConstantToRegister - Output the instructions required to put the
/// specified constant into the specified register.
unsigned getReg(Value &V) { return getReg(&V); } // Allow references
unsigned getReg(Value *V) {
unsigned &Reg = RegMap[V];
- if (Reg == 0)
+ if (Reg == 0) {
Reg = CurReg++;
+ RegMap[V] = Reg;
+
+ // Add the mapping of regnumber => reg class to MachineFunction
+ F->addRegMap(Reg,
+ TM.getRegisterInfo()->getRegClassForType(V->getType()));
+ }
// If this operand is a constant, emit the code to copy the constant into
// the register here...
//
- if (Constant *C = dyn_cast<Constant>(V))
+ if (Constant *C = dyn_cast<Constant>(V)) {
copyConstantToRegister(C, Reg);
+ } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
+ // Move the address of the global into the register
+ BuildMI(BB, X86::MOVir32, 1, Reg).addReg(GV);
+ } else if (Argument *A = dyn_cast<Argument>(V)) {
+ std::cerr << "ERROR: Arguments not implemented in SimpleInstSel\n";
+ } else {
+ assert(0 && "Don't know how to handle a value of this type!");
+ }
return Reg;
}
-
};
}
+/// TypeClass - Used by the X86 backend to group LLVM types by their basic X86
+/// Representation.
+///
+enum TypeClass {
+ cByte, cShort, cInt, cLong, cFloat, cDouble
+};
+
+/// 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::LongTyID:
+ case Type::ULongTyID: return cLong; // Longs are class #3
+ case Type::FloatTyID: return cFloat; // Float is class #4
+ case Type::DoubleTyID: return cDouble; // Doubles are class #5
+ default:
+ assert(0 && "Invalid type to getClass!");
+ return cByte; // not reached
+ }
+}
+
/// copyConstantToRegister - Output the instructions required to put the
/// specified constant into the specified register.
void ISel::copyConstantToRegister(Constant *C, unsigned R) {
assert (!isa<ConstantExpr>(C) && "Constant expressions not yet handled!\n");
- switch (C->getType()->getPrimitiveID()) {
- case Type::SByteTyID:
- BuildMI(BB, X86::MOVir8, R).addSImm(cast<ConstantSInt>(C)->getValue());
- break;
- case Type::UByteTyID:
- BuildMI(BB, X86::MOVir8, R).addZImm(cast<ConstantUInt>(C)->getValue());
+ if (C->getType()->isIntegral()) {
+ unsigned Class = getClass(C->getType());
+ assert(Class != 3 && "Type not handled yet!");
+
+ static const unsigned IntegralOpcodeTab[] = {
+ X86::MOVir8, X86::MOVir16, X86::MOVir32
+ };
+
+ if (C->getType()->isSigned()) {
+ ConstantSInt *CSI = cast<ConstantSInt>(C);
+ BuildMI(BB, IntegralOpcodeTab[Class], 1, R).addSImm(CSI->getValue());
+ } else {
+ ConstantUInt *CUI = cast<ConstantUInt>(C);
+ BuildMI(BB, IntegralOpcodeTab[Class], 1, R).addZImm(CUI->getValue());
+ }
+ } else {
+ assert(0 && "Type not handled yet!");
+ }
+}
+
+
+/// SetCC instructions - Here we just emit boilerplate code to set a byte-sized
+/// register, then move it to wherever the result should be.
+/// We handle FP setcc instructions by pushing them, doing a
+/// compare-and-pop-twice, and then copying the concodes to the main
+/// processor's concodes (I didn't make this up, it's in the Intel manual)
+///
+void ISel::visitSetCCInst(SetCondInst &I, unsigned OpNum) {
+ // The arguments are already supposed to be of the same type.
+ const Type *CompTy = I.getOperand(0)->getType();
+ unsigned reg1 = getReg(I.getOperand(0));
+ unsigned reg2 = getReg(I.getOperand(1));
+
+ unsigned Class = getClass(CompTy);
+ switch (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:
+ BuildMI (BB, X86::CMPrr8, 2).addReg (reg1).addReg (reg2);
break;
- case Type::ShortTyID:
- BuildMI(BB, X86::MOVir16, R).addSImm(cast<ConstantSInt>(C)->getValue());
+ case cShort:
+ BuildMI (BB, X86::CMPrr16, 2).addReg (reg1).addReg (reg2);
break;
- case Type::UShortTyID:
- BuildMI(BB, X86::MOVir16, R).addZImm(cast<ConstantUInt>(C)->getValue());
+ case cInt:
+ BuildMI (BB, X86::CMPrr32, 2).addReg (reg1).addReg (reg2);
break;
- case Type::IntTyID:
- BuildMI(BB, X86::MOVir32, R).addSImm(cast<ConstantSInt>(C)->getValue());
+
+ // Push the variables on the stack with fldl opcodes.
+ // FIXME: assuming var1, var2 are in memory, if not, spill to
+ // stack first
+ case cFloat: // Floats
+ BuildMI (BB, X86::FLDr4, 1).addReg (reg1);
+ BuildMI (BB, X86::FLDr4, 1).addReg (reg2);
break;
- case Type::UIntTyID:
- BuildMI(BB, X86::MOVir32, R).addZImm(cast<ConstantUInt>(C)->getValue());
+ case cDouble: // Doubles
+ BuildMI (BB, X86::FLDr8, 1).addReg (reg1);
+ BuildMI (BB, X86::FLDr8, 1).addReg (reg2);
break;
- default: assert(0 && "Type not handled yet!");
+ case cLong:
+ default:
+ visitInstruction(I);
+ }
+
+ if (CompTy->isFloatingPoint()) {
+ // (Non-trapping) compare and pop twice.
+ BuildMI (BB, X86::FUCOMPP, 0);
+ // Move fp status word (concodes) to ax.
+ BuildMI (BB, X86::FNSTSWr8, 1, X86::AX);
+ // Load real concodes from ax.
+ BuildMI (BB, X86::SAHF, 1).addReg(X86::AH);
}
+
+ // Emit setOp instruction (extract concode; clobbers ax),
+ // using the following mapping:
+ // LLVM -> X86 signed X86 unsigned
+ // ----- ----- -----
+ // seteq -> sete sete
+ // setne -> setne setne
+ // setlt -> setl setb
+ // setgt -> setg seta
+ // setle -> setle setbe
+ // setge -> setge setae
+
+ static const unsigned OpcodeTab[2][6] = {
+ {X86::SETEr, X86::SETNEr, X86::SETBr, X86::SETAr, X86::SETBEr, X86::SETAEr},
+ {X86::SETEr, X86::SETNEr, X86::SETLr, X86::SETGr, X86::SETLEr, X86::SETGEr},
+ };
+
+ BuildMI(BB, OpcodeTab[CompTy->isSigned()][OpNum], 0, X86::AL);
+
+ // Put it in the result using a move.
+ BuildMI (BB, X86::MOVrr8, 1, getReg(I)).addReg(X86::AL);
}
+/// promote32 - Emit instructions to turn a narrow operand into a 32-bit-wide
+/// operand, in the specified target register.
+void
+ISel::promote32 (const unsigned targetReg, Value *v)
+{
+ unsigned vReg = getReg (v);
+ unsigned Class = getClass (v->getType ());
+ bool isUnsigned = v->getType ()->isUnsigned ();
+ assert (((Class == cByte) || (Class == cShort) || (Class == cInt))
+ && "Unpromotable operand class in promote32");
+ switch (Class)
+ {
+ case cByte:
+ // Extend value into target register (8->32)
+ if (isUnsigned)
+ BuildMI (BB, X86::MOVZXr32r8, 1, targetReg).addReg (vReg);
+ else
+ BuildMI (BB, X86::MOVSXr32r8, 1, targetReg).addReg (vReg);
+ break;
+ case cShort:
+ // Extend value into target register (16->32)
+ if (isUnsigned)
+ BuildMI (BB, X86::MOVZXr32r16, 1, targetReg).addReg (vReg);
+ else
+ BuildMI (BB, X86::MOVSXr32r16, 1, targetReg).addReg (vReg);
+ break;
+ case cInt:
+ // Move value into target register (32->32)
+ BuildMI (BB, X86::MOVrr32, 1, targetReg).addReg (vReg);
+ break;
+ }
+}
/// 'ret' instruction - Here we are interested in meeting the x86 ABI. As such,
/// we have the following possibilities:
/// 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? XMM0?
+/// 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) { // Not 'ret void'?
- // Move result into a hard register... then emit a ret
- visitInstruction(I); // abort
+void
+ISel::visitReturnInst (ReturnInst &I)
+{
+ if (I.getNumOperands () == 0)
+ {
+ // Emit a 'ret' instruction
+ BuildMI (BB, X86::RET, 0);
+ return;
+ }
+ Value *rv = I.getOperand (0);
+ unsigned Class = getClass (rv->getType ());
+ switch (Class)
+ {
+ // integral return values: extend or move into EAX and return.
+ case cByte:
+ case cShort:
+ case cInt:
+ promote32 (X86::EAX, rv);
+ break;
+ // ret float/double: top of FP stack
+ // FLD <val>
+ case cFloat: // Floats
+ BuildMI (BB, X86::FLDr4, 1).addReg (getReg (rv));
+ break;
+ case cDouble: // Doubles
+ BuildMI (BB, X86::FLDr8, 1).addReg (getReg (rv));
+ break;
+ case cLong:
+ // ret long: use EAX(least significant 32 bits)/EDX (most
+ // significant 32)...uh, I think so Brain, but how do i call
+ // up the two parts of the value from inside this mouse
+ // cage? *zort*
+ default:
+ visitInstruction (I);
+ }
+ // Emit a 'ret' instruction
+ BuildMI (BB, X86::RET, 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)
+{
+ if (BI.isConditional ())
+ {
+ BasicBlock *ifTrue = BI.getSuccessor (0);
+ BasicBlock *ifFalse = BI.getSuccessor (1); // this is really unobvious
+
+ // simplest thing I can think of: compare condition with zero,
+ // followed by jump-if-equal to ifFalse, and jump-if-nonequal to
+ // ifTrue
+ unsigned int condReg = getReg (BI.getCondition ());
+ BuildMI (BB, X86::CMPri8, 2).addReg (condReg).addZImm (0);
+ BuildMI (BB, X86::JNE, 1).addPCDisp (BI.getSuccessor (0));
+ BuildMI (BB, X86::JE, 1).addPCDisp (BI.getSuccessor (1));
+ }
+ else // unconditional branch
+ {
+ BuildMI (BB, X86::JMP, 1).addPCDisp (BI.getSuccessor (0));
+ }
+}
+
+/// visitCallInst - Push args on stack and do a procedure call instruction.
+void
+ISel::visitCallInst (CallInst & CI)
+{
+ // Push the arguments on the stack in reverse order, as specified by
+ // the ABI.
+ for (unsigned i = CI.getNumOperands()-1; i >= 1; --i)
+ {
+ Value *v = CI.getOperand (i);
+ switch (getClass (v->getType ()))
+ {
+ case cByte:
+ case cShort:
+ // Promote V to 32 bits wide, and move the result into EAX,
+ // then push EAX.
+ promote32 (X86::EAX, v);
+ BuildMI (BB, X86::PUSHr32, 1).addReg (X86::EAX);
+ break;
+ case cInt:
+ case cFloat: {
+ unsigned Reg = getReg(v);
+ BuildMI (BB, X86::PUSHr32, 1).addReg(Reg);
+ break;
+ }
+ default:
+ // FIXME: long/ulong/double args not handled.
+ visitInstruction (CI);
+ break;
+ }
+ }
+ // Emit a CALL instruction with PC-relative displacement.
+ BuildMI (BB, X86::CALLpcrel32, 1).addPCDisp (CI.getCalledValue ());
+}
+
+/// 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) {
+ if (B.getType() == Type::BoolTy) // FIXME: Handle bools for logicals
+ visitInstruction(B);
+
+ unsigned Class = getClass(B.getType());
+ if (Class > 2) // FIXME: Handle longs
+ visitInstruction(B);
+
+ static const unsigned OpcodeTab[][4] = {
+ // Arithmetic operators
+ { X86::ADDrr8, X86::ADDrr16, X86::ADDrr32, 0 }, // ADD
+ { X86::SUBrr8, X86::SUBrr16, X86::SUBrr32, 0 }, // 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
+ };
+
+ unsigned Opcode = OpcodeTab[OperatorClass][Class];
+ unsigned Op0r = getReg(B.getOperand(0));
+ unsigned Op1r = getReg(B.getOperand(1));
+ BuildMI(BB, Opcode, 2, getReg(B)).addReg(Op0r).addReg(Op1r);
+}
+
+/// visitMul - Multiplies are not simple binary operators because they must deal
+/// with the EAX register explicitly.
+///
+void ISel::visitMul(BinaryOperator &I) {
+ unsigned Class = getClass(I.getType());
+ if (Class > 2) // FIXME: Handle longs
+ visitInstruction(I);
+
+ static const unsigned Regs[] ={ X86::AL , X86::AX , X86::EAX };
+ static const unsigned MulOpcode[]={ X86::MULrr8, X86::MULrr16, X86::MULrr32 };
+ static const unsigned MovOpcode[]={ X86::MOVrr8, X86::MOVrr16, X86::MOVrr32 };
+
+ unsigned Reg = Regs[Class];
+ unsigned Op0Reg = getReg(I.getOperand(0));
+ unsigned Op1Reg = getReg(I.getOperand(1));
+
+ // Put the first operand into one of the A registers...
+ BuildMI(BB, MovOpcode[Class], 1, Reg).addReg(Op0Reg);
+
+ // Emit the appropriate multiply instruction...
+ BuildMI(BB, MulOpcode[Class], 1).addReg(Op1Reg);
+
+ // Put the result into the destination register...
+ BuildMI(BB, MovOpcode[Class], 1, getReg(I)).addReg(Reg);
+}
+
+
+/// 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 Class = getClass(I.getType());
+ if (Class > 2) // FIXME: Handle longs
+ visitInstruction(I);
+
+ static const unsigned Regs[] ={ X86::AL , X86::AX , X86::EAX };
+ static const unsigned MovOpcode[]={ X86::MOVrr8, X86::MOVrr16, X86::MOVrr32 };
+ static const unsigned ExtOpcode[]={ X86::CBW , X86::CWD , X86::CDQ };
+ static const unsigned ClrOpcode[]={ X86::XORrr8, X86::XORrr16, X86::XORrr32 };
+ static const unsigned ExtRegs[] ={ X86::AH , X86::DX , X86::EDX };
+
+ static const unsigned DivOpcode[][4] = {
+ { X86::DIVrr8 , X86::DIVrr16 , X86::DIVrr32 , 0 }, // Unsigned division
+ { X86::IDIVrr8, X86::IDIVrr16, X86::IDIVrr32, 0 }, // Signed division
+ };
+
+ bool isSigned = I.getType()->isSigned();
+ unsigned Reg = Regs[Class];
+ unsigned ExtReg = ExtRegs[Class];
+ unsigned Op0Reg = getReg(I.getOperand(0));
+ unsigned Op1Reg = getReg(I.getOperand(1));
+
+ // Put the first operand into one of the A registers...
+ BuildMI(BB, MovOpcode[Class], 1, Reg).addReg(Op0Reg);
+
+ if (isSigned) {
+ // Emit a sign extension instruction...
+ BuildMI(BB, ExtOpcode[Class], 0);
+ } else {
+ // If unsigned, emit a zeroing instruction... (reg = xor reg, reg)
+ BuildMI(BB, ClrOpcode[Class], 2, ExtReg).addReg(ExtReg).addReg(ExtReg);
}
- // Emit a simple 'ret' instruction... appending it to the end of the basic
- // block
- BuildMI(BB, X86::RET, 0);
+ // Emit the appropriate divide or remainder instruction...
+ BuildMI(BB, DivOpcode[isSigned][Class], 1).addReg(Op1Reg);
+
+ // Figure out which register we want to pick the result out of...
+ unsigned DestReg = (I.getOpcode() == Instruction::Div) ? Reg : ExtReg;
+
+ // Put the result into the destination register...
+ BuildMI(BB, MovOpcode[Class], 1, getReg(I)).addReg(DestReg);
}
-/// 'add' instruction - Simply turn this into an x86 reg,reg add instruction.
-void ISel::visitAdd(BinaryOperator &B) {
- unsigned Op0r = getReg(B.getOperand(0)), Op1r = getReg(B.getOperand(1));
- unsigned DestReg = getReg(B);
+/// 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) {
+ unsigned Op0r = getReg (I.getOperand(0));
+ unsigned DestReg = getReg(I);
+ bool isLeftShift = I.getOpcode() == Instruction::Shl;
+ bool isOperandSigned = I.getType()->isUnsigned();
+ unsigned OperandClass = getClass(I.getType());
- switch (B.getType()->getPrimitiveSize()) {
- case 1: // UByte, SByte
- BuildMI(BB, X86::ADDrr8, DestReg).addReg(Op0r).addReg(Op1r);
- break;
- case 2: // UShort, Short
- BuildMI(BB, X86::ADDrr16, DestReg).addReg(Op0r).addReg(Op1r);
- break;
- case 4: // UInt, Int
- BuildMI(BB, X86::ADDrr32, DestReg).addReg(Op0r).addReg(Op1r);
- break;
+ if (OperandClass > 2)
+ visitInstruction(I); // Can't handle longs yet!
- case 8: // ULong, Long
- default:
- visitInstruction(B); // abort
+ if (ConstantUInt *CUI = dyn_cast <ConstantUInt> (I.getOperand (1)))
+ {
+ // The shift amount is constant, guaranteed to be a ubyte. Get its value.
+ assert(CUI->getType() == Type::UByteTy && "Shift amount not a ubyte?");
+ unsigned char shAmt = CUI->getValue();
+
+ static const unsigned ConstantOperand[][4] = {
+ { X86::SHRir8, X86::SHRir16, X86::SHRir32, 0 }, // SHR
+ { X86::SARir8, X86::SARir16, X86::SARir32, 0 }, // SAR
+ { X86::SHLir8, X86::SHLir16, X86::SHLir32, 0 }, // SHL
+ { X86::SHLir8, X86::SHLir16, X86::SHLir32, 0 }, // SAL = SHL
+ };
+
+ const unsigned *OpTab = // Figure out the operand table to use
+ ConstantOperand[isLeftShift*2+isOperandSigned];
+
+ // Emit: <insn> reg, shamt (shift-by-immediate opcode "ir" form.)
+ BuildMI(BB, OpTab[OperandClass], 2, DestReg).addReg(Op0r).addZImm(shAmt);
+ }
+ else
+ {
+ // The shift amount is non-constant.
+ //
+ // In fact, you can only shift with a variable shift amount if
+ // that amount is already in the CL register, so we have to put it
+ // there first.
+ //
+
+ // Emit: move cl, shiftAmount (put the shift amount in CL.)
+ BuildMI(BB, X86::MOVrr8, 1, X86::CL).addReg(getReg(I.getOperand(1)));
+
+ // This is a shift right (SHR).
+ static const unsigned NonConstantOperand[][4] = {
+ { X86::SHRrr8, X86::SHRrr16, X86::SHRrr32, 0 }, // SHR
+ { X86::SARrr8, X86::SARrr16, X86::SARrr32, 0 }, // SAR
+ { X86::SHLrr8, X86::SHLrr16, X86::SHLrr32, 0 }, // SHL
+ { X86::SHLrr8, X86::SHLrr16, X86::SHLrr32, 0 }, // SAL = SHL
+ };
+
+ const unsigned *OpTab = // Figure out the operand table to use
+ NonConstantOperand[isLeftShift*2+isOperandSigned];
+
+ BuildMI(BB, OpTab[OperandClass], 1, DestReg).addReg(Op0r);
+ }
+}
+
+
+/// visitLoadInst - Implement LLVM load instructions in terms of the x86 'mov'
+/// instruction.
+///
+void ISel::visitLoadInst(LoadInst &I) {
+ unsigned Class = getClass(I.getType());
+ if (Class > 2) // FIXME: Handle longs and others...
+ visitInstruction(I);
+
+ static const unsigned Opcode[] = { X86::MOVmr8, X86::MOVmr16, X86::MOVmr32 };
+
+ unsigned AddressReg = getReg(I.getOperand(0));
+ addDirectMem(BuildMI(BB, Opcode[Class], 4, getReg(I)), AddressReg);
+}
+
+
+/// visitStoreInst - Implement LLVM store instructions in terms of the x86 'mov'
+/// instruction.
+///
+void ISel::visitStoreInst(StoreInst &I) {
+ unsigned Class = getClass(I.getOperand(0)->getType());
+ if (Class > 2) // FIXME: Handle longs and others...
+ visitInstruction(I);
+
+ static const unsigned Opcode[] = { X86::MOVrm8, X86::MOVrm16, X86::MOVrm32 };
+
+ unsigned ValReg = getReg(I.getOperand(0));
+ unsigned AddressReg = getReg(I.getOperand(1));
+ addDirectMem(BuildMI(BB, Opcode[Class], 1+4), AddressReg).addReg(ValReg);
+}
+
+
+/// visitPHINode - Turn an LLVM PHI node into an X86 PHI node...
+///
+void ISel::visitPHINode(PHINode &PN) {
+ MachineInstr *MI = BuildMI(BB, X86::PHI, PN.getNumOperands(), getReg(PN));
+
+ for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
+ // FIXME: This will put constants after the PHI nodes in the block, which
+ // is invalid. They should be put inline into the PHI node eventually.
+ //
+ MI->addRegOperand(getReg(PN.getIncomingValue(i)));
+ MI->addPCDispOperand(PN.getIncomingBlock(i));
}
}
+/// visitCastInst - Here we have various kinds of copying with or without
+/// sign extension going on.
+void
+ISel::visitCastInst (CastInst &CI)
+{
+//> cast larger int to smaller int --> copy least significant byte/word w/ mov?
+//
+//I'm not really sure what to do with this. We could insert a pseudo-op
+//that says take the low X bits of a Y bit register, but for now we can just
+//force the value into, say, EAX, then rip out AL or AX. The advantage of
+//the former is that the register allocator could use any register it wants,
+//but for now this obviously doesn't matter. :)
+
+ const Type *targetType = CI.getType ();
+ Value *operand = CI.getOperand (0);
+ unsigned int operandReg = getReg (operand);
+ const Type *sourceType = operand->getType ();
+ unsigned int destReg = getReg (CI);
+
+ // cast to bool:
+ if (targetType == Type::BoolTy) {
+ // Emit Compare
+ BuildMI (BB, X86::CMPri8, 2).addReg (operandReg).addZImm (0);
+ // Emit Set-if-not-zero
+ BuildMI (BB, X86::SETNEr, 1, destReg);
+ return;
+ }
+// if size of target type == size of source type
+// Emit Mov reg(target) <- reg(source)
+
+// if size of target type > size of source type
+// if both types are integer types
+// if source type is signed
+// sbyte to short, ushort: Emit movsx 8->16
+// sbyte to int, uint: Emit movsx 8->32
+// short to int, uint: Emit movsx 16->32
+// else if source type is unsigned
+// ubyte to short, ushort: Emit movzx 8->16
+// ubyte to int, uint: Emit movzx 8->32
+// ushort to int, uint: Emit movzx 16->32
+// if both types are fp types
+// float to double: Emit fstp, fld (???)
+
+ visitInstruction (CI);
+}
-/// X86SimpleInstructionSelection - This function converts an LLVM function into
-/// a machine code representation is a very simple peep-hole fashion. The
+/// createSimpleX86InstructionSelector - 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.
///
-MachineFunction *X86SimpleInstructionSelection(Function &F, TargetMachine &TM) {
- MachineFunction *Result = new MachineFunction(&F, TM);
- ISel(Result).runOnFunction(F);
- return Result;
+Pass *createSimpleX86InstructionSelector(TargetMachine &TM) {
+ return new ISel(TM);
}
projects / oota-llvm.git / blobdiff