// makeConstant creates the value node and object node (if needed) for
// constant c, and returns the value node.
// An object node is created only for []byte or []rune constants.
// The value node points to the object node, iff present.
//
func (a *analysis) makeConstant(l *ssa.Const) nodeid {
id := a.addNodes(l.Type(), "const")
if !l.IsNil() {
// []byte or []rune?
if t, ok := l.Type().Underlying().(*types.Slice); ok {
// Treat []T like *[1]T, 'make []T' like new([1]T).
obj := a.nextNode()
a.addNodes(sliceToArray(t), "array in slice constant")
a.endObject(obj, nil, l)
a.addressOf(id, obj)
}
}
return id
}
// constValue returns the value of the constant with the
// dynamic type tag appropriate for c.Type().
func constValue(c *ssa.Const) value {
if c.IsNil() {
return zero(c.Type()) // typed nil
}
// By destination type:
switch t := c.Type().Underlying().(type) {
case *types.Basic:
// TODO(adonovan): eliminate untyped constants from SSA form.
switch t.Kind() {
case types.Bool, types.UntypedBool:
return exact.BoolVal(c.Value)
case types.Int, types.UntypedInt:
// Assume sizeof(int) is same on host and target.
return int(c.Int64())
case types.Int8:
return int8(c.Int64())
case types.Int16:
return int16(c.Int64())
case types.Int32, types.UntypedRune:
return int32(c.Int64())
case types.Int64:
return c.Int64()
case types.Uint:
// Assume sizeof(uint) is same on host and target.
return uint(c.Uint64())
case types.Uint8:
return uint8(c.Uint64())
case types.Uint16:
return uint16(c.Uint64())
case types.Uint32:
return uint32(c.Uint64())
case types.Uint64:
return c.Uint64()
case types.Uintptr:
// Assume sizeof(uintptr) is same on host and target.
return uintptr(c.Uint64())
case types.Float32:
return float32(c.Float64())
case types.Float64, types.UntypedFloat:
return c.Float64()
case types.Complex64:
return complex64(c.Complex128())
case types.Complex128, types.UntypedComplex:
return c.Complex128()
case types.String, types.UntypedString:
if c.Value.Kind() == exact.String {
return exact.StringVal(c.Value)
}
return string(rune(c.Int64()))
case types.UnsafePointer:
panic("unsafe.Pointer constant") // not possible
case types.UntypedNil:
// nil was handled above.
}
case *types.Slice:
switch et := t.Elem().Underlying().(type) {
case *types.Basic:
switch et.Kind() {
case types.Byte: // string -> []byte
var v []value
for _, b := range []byte(exact.StringVal(c.Value)) {
v = append(v, b)
}
return v
case types.Rune: // string -> []rune
var v []value
for _, r := range []rune(exact.StringVal(c.Value)) {
v = append(v, r)
}
return v
}
}
}
panic(fmt.Sprintf("constValue: Value.(type)=%T Type()=%s", c.Value, c.Type()))
}