// If this value is sufficiently large, look through referrers to see if we can
// avoid a load.
func (fr *frame) canAvoidLoad(instr *ssa.UnOp, op llvm.Value) bool {
if fr.types.Sizeof(instr.Type()) < 16 {
// Don't bother with small values.
return false
}
// Keep track of whether our pointer may escape. We conservatively assume
// that MakeInterfaces will escape.
esc := false
// We only know how to avoid loads if they are used to create an interface
// or read an element of the structure. If we see any other referrer, abort.
for _, ref := range *instr.Referrers() {
switch ref.(type) {
case *ssa.MakeInterface:
esc = true
case *ssa.Field, *ssa.Index:
// ok
default:
return false
}
}
var opcopy llvm.Value
if esc {
opcopy = fr.createTypeMalloc(instr.Type())
} else {
opcopy = fr.allocaBuilder.CreateAlloca(fr.types.ToLLVM(instr.Type()), "")
}
fr.memcpy(opcopy, op, llvm.ConstInt(fr.types.inttype, uint64(fr.types.Sizeof(instr.Type())), false))
fr.ptr[instr] = opcopy
return true
}
// arithmetic negation
func (f *Function) UnOpSub(instr *ssa.UnOp) (string, *Error) {
ctx := context{f, instr}
if ident := f.Ident(instr); ident == nil {
return ErrorMsg(fmt.Sprintf("Cannot alloc value: %v", instr))
}
var regSubX, regX, regVal *register
var a1, a2 string
a1, regVal = f.allocReg(instr, regType(instr.Type()), f.sizeof(instr))
a2, regSubX = f.allocReg(instr, regType(instr.X.Type()), f.sizeof(instr.X))
addr, ok := f.identifiers[instr.Name()]
if !ok {
msg := fmt.Sprintf("unknown name (%v), instr (%v)\n", instr.Name(), instr)
ice(msg)
}
a3, regX, err := f.LoadValueSimple(instr, instr.X)
asm := a1 + a2 + a3
if err != nil {
return asm, err
}
asm += ZeroReg(ctx, regSubX)
optypes := GetOpDataType(instr.Type())
asm += ArithOp(ctx, optypes, token.SUB, regSubX, regX, regVal)
f.freeReg(regX)
f.freeReg(regSubX)
a, err := f.StoreValue(instr, addr, regVal)
if err != nil {
return asm, err
} else {
asm += a
}
f.freeReg(regVal)
asm = fmt.Sprintf("// BEGIN ssa.UnOpSub, %v = %v\n", instr.Name(), instr) + asm
asm += fmt.Sprintf("// END ssa.UnOpSub, %v = %v\n", instr.Name(), instr)
return asm, nil
}
//pointer indirection, in assignment such as "z = *x"
func (f *Function) UnOpPointer(instr *ssa.UnOp) (string, *Error) {
asm := ""
assignment := f.Ident(instr)
if assignment == nil {
return ErrorMsg(fmt.Sprintf("Cannot alloc value: %v", instr))
}
xName := instr.X.Name()
xInfo, okX := f.identifiers[xName]
if !xInfo.isSsaLocal() && xInfo.param == nil && xInfo.ptr == nil {
panic("unexpected nil ptr")
} else if !xInfo.isSsaLocal() && xInfo.param == nil {
asm += xInfo.ptr.spillAllRegisters(instr)
}
// TODO add complex64/128 support
if isComplex(instr.Type()) || isComplex(instr.X.Type()) {
return ErrorMsg("complex64/complex128 unimplemented")
}
if !okX {
msgstr := "Unknown name for UnOp X (%v), instr \"(%v)\""
ice(fmt.Sprintf(msgstr, instr.X, instr))
}
if xInfo.local == nil && xInfo.param == nil && !xInfo.isPointer() {
fmtstr := "in UnOp, X (%v) isn't a pointer, X.type (%v), instr \"(%v)\""
msg := fmt.Sprintf(fmtstr, instr.X, instr.X.Type(), instr)
ice(msg)
}
_, _, size := assignment.Addr()
if xInfo.isSsaLocal() {
ctx := context{f, instr}
a, reg := xInfo.load(ctx)
asm += a
asm += assignment.newValue(ctx, reg, 0, xInfo.size())
f.freeReg(reg)
} else {
var tmpData *register
var a1 string
if isXmm(instr.Type()) {
a1, tmpData = f.allocReg(instr, XMM_REG, XmmRegSize)
} else {
a1, tmpData = f.allocReg(instr, regType(instr.Type()), DataRegSize)
}
asm += a1
var a2 string
var tmpAddr *register
a2, tmpAddr = f.allocReg(instr, DATA_REG, DataRegSize)
asm += a2
src, ok := xInfo.storage.(*memory)
if !ok {
ice("cannot dereference pointer to constant")
}
dst, ok := assignment.storage.(*memory)
if !ok {
ice("cannot modify constant")
}
dst.removeAliases()
ctx := context{f, instr}
a, srcReg := src.load(ctx, src.ownerRegion())
asm += a
aReg, aOffset, _ := assignment.Addr()
asm += MovRegIndirectMem(ctx, dst.optype(), srcReg, assignment.name, aOffset, &aReg, size, tmpAddr, tmpData)
dst.setInitialized(region{0, size})
f.freeReg(srcReg)
f.freeReg(tmpAddr)
f.freeReg(tmpData)
}
asm = fmt.Sprintf("// BEGIN ssa.UnOpPointer, %v = %v\n", instr.Name(), instr) + asm
asm += fmt.Sprintf("// END ssa.UnOpPointer, %v = %v\n", instr.Name(), instr)
return asm, nil
}
func visitDeref(inst *ssa.UnOp, fr *frame) {
ptr := inst.X
val := inst
if _, ok := ptr.(*ssa.Global); ok {
fr.locals[ptr] = fr.env.globals[ptr]
fmt.Fprintf(os.Stderr, " %s = *%s (global) of type %s\n", cyan(reg(val)), ptr.Name(), ptr.Type().String())
fmt.Fprintf(os.Stderr, " ^ i.e. %s\n", fr.locals[ptr].String())
switch deref(fr.locals[ptr].Var.Type()).(type) {
case *types.Array, *types.Slice:
if _, ok := fr.env.arrays[fr.env.globals[ptr]]; !ok {
fr.env.arrays[fr.env.globals[ptr]] = make(Elems)
}
case *types.Struct:
if _, ok := fr.env.structs[fr.env.globals[ptr]]; !ok {
fr.env.structs[fr.env.globals[ptr]] = make(Fields)
}
}
}
switch vd, kind := fr.get(ptr); kind {
case Array, LocalArray:
fr.locals[val] = vd
fmt.Fprintf(os.Stderr, " %s = *%s (array)\n", cyan(reg(val)), ptr.Name())
case Struct, LocalStruct:
fr.locals[val] = vd
fmt.Fprintf(os.Stderr, " %s = *%s (struct)\n", cyan(reg(val)), ptr.Name())
case Chan:
fr.locals[val] = vd
fmt.Fprintf(os.Stderr, " %s = *%s (previously initalised Chan)\n", cyan(reg(val)), ptr.Name())
case Nothing:
fmt.Fprintf(os.Stderr, " # %s = *%s (not found)\n", red(inst.String()), red(inst.X.String()))
if _, ok := val.Type().Underlying().(*types.Chan); ok {
fmt.Fprintf(os.Stderr, " ^ channel (not allocated, must be initialised by MakeChan)")
}
default:
fmt.Fprintf(os.Stderr, " # %s = *%s/%s (not found, type=%s)\n", red(inst.String()), red(inst.X.String()), reg(inst.X), inst.Type().String())
}
}