func (v Target) genConvert(a *allocator, instr *ssa.Convert) {
op := ssa.GetOperands(instr)[0]
checkTypeSupported(op.Type())
checkTypeSupported(instr.Type())
targetStoresz := TypeStoreSizeInBits(instr.Type())
targetsz := TypeSizeInBits(instr.Type())
opsz := TypeSizeInBits(op.Type())
switch instr.ConvertType() {
case ssa.ConvertBitcast:
v.moveValToVal(a, op, instr)
case ssa.ConvertTrunc:
v.moveIntToReg(a, op, "rax")
if !isRegSizeBits(targetsz) {
v.wop("andq $%d, #rax", (1<<uint(targetsz))-1)
}
v.wop("mov%s #%s, %s", sizeSuffixBits(targetStoresz), regToSize("rax", targetStoresz), a.valStr(instr))
case ssa.ConvertZExt:
v.moveIntToReg(a, op, "rax")
v.moveRegToVal(a, "rax", instr)
case ssa.ConvertSExt:
v.genSExt(a, instr, op, opsz, targetStoresz, targetsz)
case ssa.ConvertIntToPtr, ssa.ConvertPtrToInt:
v.moveIntToReg(a, op, "rax")
v.moveRegToVal(a, "rax", instr)
default:
panic("unim")
}
}
// this function is bad
func checkConvert(instr *ssa.Convert) error {
ops := ssa.GetOperands(instr)
srcType := ops[0].Type()
destType := instr.Type()
mustBeInt := make([]types.Type, 0, 2)
mustBeFloat := make([]types.Type, 0, 2)
mustBePointer := make([]types.Type, 0, 2)
switch instr.ConvertType() {
case ssa.ConvertSExt, ssa.ConvertZExt, ssa.ConvertTrunc:
mustBeInt = append(mustBeInt, srcType, destType)
case ssa.ConvertBitcast:
mustBePointer = append(mustBePointer, srcType, destType)
case ssa.ConvertFExt, ssa.ConvertFTrunc:
mustBeFloat = append(mustBeFloat, srcType, destType)
case ssa.ConvertFToUI, ssa.ConvertFToSI:
mustBeFloat = append(mustBeFloat, srcType)
mustBeInt = append(mustBeInt, destType)
case ssa.ConvertUIToF, ssa.ConvertSIToF:
mustBeFloat = append(mustBeFloat, destType)
mustBeInt = append(mustBeInt, srcType)
case ssa.ConvertPtrToInt:
mustBePointer = append(mustBePointer, srcType)
mustBeInt = append(mustBeInt, destType)
case ssa.ConvertIntToPtr:
mustBeInt = append(mustBeInt, srcType)
mustBePointer = append(mustBePointer, destType)
default:
panic("unim")
}
for _, t := range mustBeInt {
if err := errIfNotIntType(instr, t); err != nil {
return err
}
}
for _, t := range mustBeFloat {
if err := errIfNotFloatType(instr, t); err != nil {
return err
}
}
for _, t := range mustBePointer {
if err := errIfNotPointerType(instr, t); err != nil {
return err
}
}
instrError := func(message string) error {
return &InstrError{
Instr: instr,
Message: message,
}
}
switch instr.ConvertType() {
case ssa.ConvertSExt, ssa.ConvertZExt:
if srcType.(*types.Int).Width() >= destType.(*types.Int).Width() {
return instrError("sext/zext requires src width < dest width")
}
case ssa.ConvertTrunc:
if srcType.(*types.Int).Width() <= destType.(*types.Int).Width() {
return instrError("trunc requires src width > dest width")
}
case ssa.ConvertBitcast:
// do nothing
case ssa.ConvertFExt:
if srcType.(*types.Float).Type().CanExtendTo(destType.(*types.Float).Type()) {
return instrError("fext cannot convert from " + srcType.String() + " to " + destType.String())
}
case ssa.ConvertFTrunc:
if srcType.(*types.Float).Type().CanTruncateTo(destType.(*types.Float).Type()) {
return instrError("ftrunc cannot convert from " + srcType.String() + " to " + destType.String())
}
case ssa.ConvertFToUI, ssa.ConvertFToSI, ssa.ConvertUIToF, ssa.ConvertSIToF, ssa.ConvertPtrToInt, ssa.ConvertIntToPtr:
// nothing to do
default:
panic("unim")
}
return nil
}