} 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 {
- assert(0 && "Don't know how to handle a value of this type!");
+ } else if (Argument *A = dyn_cast<Argument>(V)) {
+ std::cerr << "ERROR: Arguments not implemented in SimpleInstSel\n";
}
return Reg;
void
ISel::visitCallInst (CallInst & CI)
{
+ // keep a counter of how many bytes we pushed on the stack
+ unsigned bytesPushed = 0;
+
// Push the arguments on the stack in reverse order, as specified by
// the ABI.
for (unsigned i = CI.getNumOperands()-1; i >= 1; --i)
// then push EAX.
promote32 (X86::EAX, v);
BuildMI (BB, X86::PUSHr32, 1).addReg (X86::EAX);
+ bytesPushed += 4;
break;
case cInt:
case cFloat: {
unsigned Reg = getReg(v);
BuildMI (BB, X86::PUSHr32, 1).addReg(Reg);
+ bytesPushed += 4;
break;
}
default:
}
// Emit a CALL instruction with PC-relative displacement.
BuildMI (BB, X86::CALLpcrel32, 1).addPCDisp (CI.getCalledValue ());
+
+ // Adjust the stack by `bytesPushed' amount if non-zero
+ if (bytesPushed > 0)
+ BuildMI (BB, X86::ADDri32, 2).addReg(X86::ESP).addZImm(bytesPushed);
+
+ // If there is a return value, scavenge the result from the location the call
+ // leaves it in...
+ //
+ if (CI.getType() != Type::VoidTy) {
+ switch (getClass(CI.getType())) {
+ case cInt:
+ BuildMI(BB, X86::MOVrr32, 1, getReg(CI)).addReg(X86::EAX);
+ break;
+
+ default:
+ std::cerr << "Cannot get return value for call of type '"
+ << *CI.getType() << "'\n";
+ visitInstruction(CI);
+ }
+ }
}
/// visitSimpleBinary - Implement simple binary operators for integral types...
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 (???)
-
+ //
+ // Currently we handle:
+ //
+ // 1) cast * to bool
+ //
+ // 2) cast {sbyte, ubyte} to {sbyte, ubyte}
+ // cast {short, ushort} to {ushort, short}
+ // cast {int, uint, ptr} to {int, uint, ptr}
+ //
+ // 3) cast {sbyte, ubyte} to {ushort, short}
+ // cast {sbyte, ubyte} to {int, uint, ptr}
+ // cast {short, ushort} to {int, uint, ptr}
+ //
+ // 4) cast {int, uint, ptr} to {short, ushort}
+ // cast {int, uint, ptr} to {sbyte, ubyte}
+ // cast {short, ushort} to {sbyte, ubyte}
+ //
+ // 1) Implement casts to bool by using compare on the operand followed
+ // by set if not zero on the result.
+ if (targetType == Type::BoolTy)
+ {
+ BuildMI (BB, X86::CMPri8, 2).addReg (operandReg).addZImm (0);
+ BuildMI (BB, X86::SETNEr, 1, destReg);
+ return;
+ }
+ // 2) Implement casts between values of the same type class (as determined
+ // by getClass) by using a register-to-register move.
+ unsigned int srcClass = getClass (sourceType);
+ unsigned int targClass = getClass (targetType);
+ static const unsigned regRegMove[] = {
+ X86::MOVrr8, X86::MOVrr16, X86::MOVrr32
+ };
+ if ((srcClass < 3) && (targClass < 3) && (srcClass == targClass))
+ {
+ BuildMI (BB, regRegMove[srcClass], 1, destReg).addReg (operandReg);
+ return;
+ }
+ // 3) 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 < 3) && (targClass < 3) && (srcClass < targClass))
+ {
+ static const unsigned ops[] = {
+ X86::MOVSXr16r8, X86::MOVSXr32r8, X86::MOVSXr32r16,
+ X86::MOVZXr16r8, X86::MOVZXr32r8, X86::MOVZXr32r16
+ };
+ unsigned srcSigned = sourceType->isSigned ();
+ BuildMI (BB, ops[3 * srcSigned + srcClass + targClass - 1], 1,
+ destReg).addReg (operandReg);
+ return;
+ }
+ // 4) Handle cast of LARGER int to SMALLER int using a move to EAX
+ // followed by a move out of AX or AL.
+ if ((srcClass < 3) && (targClass < 3) && (srcClass > targClass))
+ {
+ static const unsigned AReg[] = { X86::AL, X86::AX, X86::EAX };
+ BuildMI (BB, regRegMove[srcClass], 1,
+ AReg[srcClass]).addReg (operandReg);
+ BuildMI (BB, regRegMove[targClass], 1, destReg).addReg (AReg[srcClass]);
+ return;
+ }
+ // Anything we haven't handled already, we can't (yet) handle at all.
visitInstruction (CI);
}
projects / oota-llvm.git / blobdiff