// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gc
import (
"cmd/compile/internal/types"
"math/big"
"strings"
)
// Ctype describes the constant kind of an "ideal" (untyped) constant.
type Ctype uint8
const (
CTxxx Ctype = iota
CTINT
CTRUNE
CTFLT
CTCPLX
CTSTR
CTBOOL
CTNIL
)
type Val struct {
// U contains one of:
// bool bool when Ctype() == CTBOOL
// *Mpint int when Ctype() == CTINT, rune when Ctype() == CTRUNE
// *Mpflt float when Ctype() == CTFLT
// *Mpcplx pair of floats when Ctype() == CTCPLX
// string string when Ctype() == CTSTR
// *Nilval when Ctype() == CTNIL
U interface{}
}
func (v Val) Ctype() Ctype {
switch x := v.U.(type) {
default:
Fatalf("unexpected Ctype for %T", v.U)
panic("unreachable")
case nil:
return 0
case *NilVal:
return CTNIL
case bool:
return CTBOOL
case *Mpint:
if x.Rune {
return CTRUNE
}
return CTINT
case *Mpflt:
return CTFLT
case *Mpcplx:
return CTCPLX
case string:
return CTSTR
}
}
func eqval(a, b Val) bool {
if a.Ctype() != b.Ctype() {
return false
}
switch x := a.U.(type) {
default:
Fatalf("unexpected Ctype for %T", a.U)
panic("unreachable")
case *NilVal:
return true
case bool:
y := b.U.(bool)
return x == y
case *Mpint:
y := b.U.(*Mpint)
return x.Cmp(y) == 0
case *Mpflt:
y := b.U.(*Mpflt)
return x.Cmp(y) == 0
case *Mpcplx:
y := b.U.(*Mpcplx)
return x.Real.Cmp(&y.Real) == 0 && x.Imag.Cmp(&y.Imag) == 0
case string:
y := b.U.(string)
return x == y
}
}
// Interface returns the constant value stored in v as an interface{}.
// It returns int64s for ints and runes, float64s for floats,
// complex128s for complex values, and nil for constant nils.
func (v Val) Interface() interface{} {
switch x := v.U.(type) {
default:
Fatalf("unexpected Interface for %T", v.U)
panic("unreachable")
case *NilVal:
return nil
case bool, string:
return x
case *Mpint:
return x.Int64()
case *Mpflt:
return x.Float64()
case *Mpcplx:
return complex(x.Real.Float64(), x.Imag.Float64())
}
}
type NilVal struct{}
// Int64 returns n as an int64.
// n must be an integer or rune constant.
func (n *Node) Int64() int64 {
if !Isconst(n, CTINT) {
Fatalf("Int64(%v)", n)
}
return n.Val().U.(*Mpint).Int64()
}
// CanInt64 reports whether it is safe to call Int64() on n.
func (n *Node) CanInt64() bool {
if !Isconst(n, CTINT) {
return false
}
// if the value inside n cannot be represented as an int64, the
// return value of Int64 is undefined
return n.Val().U.(*Mpint).CmpInt64(n.Int64()) == 0
}
// Bool returns n as a bool.
// n must be a boolean constant.
func (n *Node) Bool() bool {
if !Isconst(n, CTBOOL) {
Fatalf("Bool(%v)", n)
}
return n.Val().U.(bool)
}
// truncate float literal fv to 32-bit or 64-bit precision
// according to type; return truncated value.
func truncfltlit(oldv *Mpflt, t *types.Type) *Mpflt {
if t == nil {
return oldv
}
if overflow(Val{oldv}, t) {
// If there was overflow, simply continuing would set the
// value to Inf which in turn would lead to spurious follow-on
// errors. Avoid this by returning the existing value.
return oldv
}
fv := newMpflt()
// convert large precision literal floating
// into limited precision (float64 or float32)
switch t.Etype {
case types.TFLOAT32:
fv.SetFloat64(oldv.Float32())
case types.TFLOAT64:
fv.SetFloat64(oldv.Float64())
default:
Fatalf("truncfltlit: unexpected Etype %v", t.Etype)
}
return fv
}
// truncate Real and Imag parts of Mpcplx to 32-bit or 64-bit
// precision, according to type; return truncated value. In case of
// overflow, calls yyerror but does not truncate the input value.
func trunccmplxlit(oldv *Mpcplx, t *types.Type) *Mpcplx {
if t == nil {
return oldv
}
if overflow(Val{oldv}, t) {
// If there was overflow, simply continuing would set the
// value to Inf which in turn would lead to spurious follow-on
// errors. Avoid this by returning the existing value.
return oldv
}
cv := newMpcmplx()
switch t.Etype {
case types.TCOMPLEX64:
cv.Real.SetFloat64(oldv.Real.Float32())
cv.Imag.SetFloat64(oldv.Imag.Float32())
case types.TCOMPLEX128:
cv.Real.SetFloat64(oldv.Real.Float64())
cv.Imag.SetFloat64(oldv.Imag.Float64())
default:
Fatalf("trunccplxlit: unexpected Etype %v", t.Etype)
}
return cv
}
// canReuseNode indicates whether it is known to be safe
// to reuse a Node.
type canReuseNode bool
const (
noReuse canReuseNode = false // not necessarily safe to reuse
reuseOK canReuseNode = true // safe to reuse
)
// convert n, if literal, to type t.
// implicit conversion.
// The result of convlit MUST be assigned back to n, e.g.
// n.Left = convlit(n.Left, t)
func convlit(n *Node, t *types.Type) *Node {
return convlit1(n, t, false, noReuse)
}
// convlit1 converts n, if literal, to type t.
// It returns a new node if necessary.
// The result of convlit1 MUST be assigned back to n, e.g.
// n.Left = convlit1(n.Left, t, explicit, reuse)
func convlit1(n *Node, t *types.Type, explicit bool, reuse canReuseNode) *Node {
if n == nil || t == nil || n.Type == nil || t.IsUntyped() || n.Type == t {
return n
}
if !explicit && !n.Type.IsUntyped() {
return n
}
if n.Op == OLITERAL && !reuse {
// Can't always set n.Type directly on OLITERAL nodes.
// See discussion on CL 20813.
n = n.rawcopy()
reuse = true
}
switch n.Op {
default:
if n.Type == types.Idealbool {
if !t.IsBoolean() {
t = types.Types[TBOOL]
}
switch n.Op {
case ONOT:
n.Left = convlit(n.Left, t)
case OANDAND, OOROR:
n.Left = convlit(n.Left, t)
n.Right = convlit(n.Right, t)
}
n.Type = t
}
if n.Type.IsUntyped() {
if t.IsInterface() {
n.Left, n.Right = defaultlit2(n.Left, n.Right, true)
n.Type = n.Left.Type // same as n.Right.Type per defaultlit2
} else {
n.Left = convlit(n.Left, t)
n.Right = convlit(n.Right, t)
n.Type = t
}
}
return n
// target is invalid type for a constant? leave alone.
case OLITERAL:
if !okforconst[t.Etype] && n.Type.Etype != TNIL {
return defaultlitreuse(n, nil, reuse)
}
case OLSH, ORSH:
n.Left = convlit1(n.Left, t, explicit && n.Left.Type.IsUntyped(), noReuse)
t = n.Left.Type
if t != nil && t.Etype == TIDEAL && n.Val().Ctype() != CTINT {
n.SetVal(toint(n.Val()))
}
if t != nil && !t.IsInteger() {
yyerror("invalid operation: %v (shift of type %v)", n, t)
t = nil
}
n.Type = t
return n
case OCOMPLEX:
if n.Type.Etype == TIDEAL {
switch t.Etype {
default:
// If trying to convert to non-complex type,
// leave as complex128 and let typechecker complain.
t = types.Types[TCOMPLEX128]
fallthrough
case types.TCOMPLEX128:
n.Type = t
n.Left = convlit(n.Left, types.Types[TFLOAT64])
n.Right = convlit(n.Right, types.Types[TFLOAT64])
case TCOMPLEX64:
n.Type = t
n.Left = convlit(n.Left, types.Types[TFLOAT32])
n.Right = convlit(n.Right, types.Types[TFLOAT32])
}
}
return n
}
// avoid repeated calculations, errors
if types.Identical(n.Type, t) {
return n
}
ct := consttype(n)
var et types.EType
if ct == 0 {
goto bad
}
et = t.Etype
if et == TINTER {
if ct == CTNIL && n.Type == types.Types[TNIL] {
n.Type = t
return n
}
return defaultlitreuse(n, nil, reuse)
}
switch ct {
default:
goto bad
case CTNIL:
switch et {
default:
n.Type = nil
goto bad
// let normal conversion code handle it
case TSTRING:
return n
case TARRAY:
goto bad
case TPTR, TUNSAFEPTR:
n.SetVal(Val{new(Mpint)})
case TCHAN, TFUNC, TINTER, TMAP, TSLICE:
break
}
case CTSTR, CTBOOL:
if et != n.Type.Etype {
goto bad
}
case CTINT, CTRUNE, CTFLT, CTCPLX:
if n.Type.Etype == TUNSAFEPTR && t.Etype != TUINTPTR {
goto bad
}
ct := n.Val().Ctype()
if isInt[et] {
switch ct {
default:
goto bad
case CTCPLX, CTFLT, CTRUNE:
n.SetVal(toint(n.Val()))
fallthrough
case CTINT:
overflow(n.Val(), t)
}
} else if isFloat[et] {
switch ct {
default:
goto bad
case CTCPLX, CTINT, CTRUNE:
n.SetVal(toflt(n.Val()))
fallthrough
case CTFLT:
n.SetVal(Val{truncfltlit(n.Val().U.(*Mpflt), t)})
}
} else if isComplex[et] {
switch ct {
default:
goto bad
case CTFLT, CTINT, CTRUNE:
n.SetVal(tocplx(n.Val()))
fallthrough
case CTCPLX:
n.SetVal(Val{trunccmplxlit(n.Val().U.(*Mpcplx), t)})
}
} else if et == types.TSTRING && (ct == CTINT || ct == CTRUNE) && explicit {
n.SetVal(tostr(n.Val()))
} else {
goto bad
}
}
n.Type = t
return n
bad:
if !n.Diag() {
if !t.Broke() {
yyerror("cannot convert %L to type %v", n, t)
}
n.SetDiag(true)
}
if n.Type.IsUntyped() {
n = defaultlitreuse(n, nil, reuse)
}
return n
}
func tocplx(v Val) Val {
switch u := v.U.(type) {
case *Mpint:
c := newMpcmplx()
c.Real.SetInt(u)
c.Imag.SetFloat64(0.0)
v.U = c
case *Mpflt:
c := newMpcmplx()
c.Real.Set(u)
c.Imag.SetFloat64(0.0)
v.U = c
}
return v
}
func toflt(v Val) Val {
switch u := v.U.(type) {
case *Mpint:
f := newMpflt()
f.SetInt(u)
v.U = f
case *Mpcplx:
f := newMpflt()
f.Set(&u.Real)
if u.Imag.CmpFloat64(0) != 0 {
yyerror("constant %v truncated to real", u.GoString())
}
v.U = f
}
return v
}
func toint(v Val) Val {
switch u := v.U.(type) {
case *Mpint:
if u.Rune {
i := new(Mpint)
i.Set(u)
v.U = i
}
case *Mpflt:
i := new(Mpint)
if !i.SetFloat(u) {
if i.checkOverflow(0) {
yyerror("integer too large")
} else {
// The value of u cannot be represented as an integer;
// so we need to print an error message.
// Unfortunately some float values cannot be
// reasonably formatted for inclusion in an error
// message (example: 1 + 1e-100), so first we try to
// format the float; if the truncation resulted in
// something that looks like an integer we omit the
// value from the error message.
// (See issue #11371).
var t big.Float
t.Parse(u.GoString(), 10)
if t.IsInt() {
yyerror("constant truncated to integer")
} else {
yyerror("constant %v truncated to integer", u.GoString())
}
}
}
v.U = i
case *Mpcplx:
i := new(Mpint)
if !i.SetFloat(&u.Real) || u.Imag.CmpFloat64(0) != 0 {
yyerror("constant %v truncated to integer", u.GoString())
}
v.U = i
}
return v
}
func doesoverflow(v Val, t *types.Type) bool {
switch u := v.U.(type) {
case *Mpint:
if !t.IsInteger() {
Fatalf("overflow: %v integer constant", t)
}
return u.Cmp(minintval[t.Etype]) < 0 || u.Cmp(maxintval[t.Etype]) > 0
case *Mpflt:
if !t.IsFloat() {
Fatalf("overflow: %v floating-point constant", t)
}
return u.Cmp(minfltval[t.Etype]) <= 0 || u.Cmp(maxfltval[t.Etype]) >= 0
case *Mpcplx:
if !t.IsComplex() {
Fatalf("overflow: %v complex constant", t)
}
return u.Real.Cmp(minfltval[t.Etype]) <= 0 || u.Real.Cmp(maxfltval[t.Etype]) >= 0 ||
u.Imag.Cmp(minfltval[t.Etype]) <= 0 || u.Imag.Cmp(maxfltval[t.Etype]) >= 0
}
return false
}
func overflow(v Val, t *types.Type) bool {
// v has already been converted
// to appropriate form for t.
if t == nil || t.Etype == TIDEAL {
return false
}
// Only uintptrs may be converted to pointers, which cannot overflow.
if t.IsPtr() || t.IsUnsafePtr() {
return false
}
if doesoverflow(v, t) {
yyerror("constant %v overflows %v", v, t)
return true
}
return false
}
func tostr(v Val) Val {
switch u := v.U.(type) {
case *Mpint:
var i int64 = 0xFFFD
if u.Cmp(minintval[TUINT32]) >= 0 && u.Cmp(maxintval[TUINT32]) <= 0 {
i = u.Int64()
}
v.U = string(i)
}
return v
}
func consttype(n *Node) Ctype {
if n == nil || n.Op != OLITERAL {
return 0
}
return n.Val().Ctype()
}
func Isconst(n *Node, ct Ctype) bool {
t := consttype(n)
// If the caller is asking for CTINT, allow CTRUNE too.
// Makes life easier for back ends.
return t == ct || (ct == CTINT && t == CTRUNE)
}
// evconst rewrites constant expressions into OLITERAL nodes.
func evconst(n *Node) {
nl, nr := n.Left, n.Right
// Pick off just the opcodes that can be constant evaluated.
switch op := n.Op; op {
case OPLUS, ONEG, OBITNOT, ONOT:
if nl.Op == OLITERAL {
setconst(n, unaryOp(op, nl.Val(), n.Type))
}
case OADD, OSUB, OMUL, ODIV, OMOD, OOR, OXOR, OAND, OANDNOT, OOROR, OANDAND:
if nl.Op == OLITERAL && nr.Op == OLITERAL {
setconst(n, binaryOp(nl.Val(), op, nr.Val()))
}
case OEQ, ONE, OLT, OLE, OGT, OGE:
if nl.Op == OLITERAL && nr.Op == OLITERAL {
if nl.Type.IsInterface() != nr.Type.IsInterface() {
// Mixed interface/non-interface
// constant comparison means comparing
// nil interface with some typed
// constant, which is always unequal.
// E.g., interface{}(nil) == (*int)(nil).
setboolconst(n, op == ONE)
} else {
setboolconst(n, compareOp(nl.Val(), op, nr.Val()))
}
}
case OLSH, ORSH:
if nl.Op == OLITERAL && nr.Op == OLITERAL {
setconst(n, shiftOp(nl.Val(), op, nr.Val()))
}
case OCONV:
if okforconst[n.Type.Etype] && nl.Op == OLITERAL {
// TODO(mdempsky): There should be a convval function.
setconst(n, convlit1(nl, n.Type, true, false).Val())
}
case OCONVNOP:
if okforconst[n.Type.Etype] && nl.Op == OLITERAL {
// set so n.Orig gets OCONV instead of OCONVNOP
n.Op = OCONV
setconst(n, nl.Val())
}
case OADDSTR:
// Merge adjacent constants in the argument list.
s := n.List.Slice()
for i1 := 0; i1 < len(s); i1++ {
if Isconst(s[i1], CTSTR) && i1+1 < len(s) && Isconst(s[i1+1], CTSTR) {
// merge from i1 up to but not including i2
var strs []string
i2 := i1
for i2 < len(s) && Isconst(s[i2], CTSTR) {
strs = append(strs, s[i2].Val().U.(string))
i2++
}
nl := *s[i1]
nl.Orig = &nl
nl.SetVal(Val{strings.Join(strs, "")})
s[i1] = &nl
s = append(s[:i1+1], s[i2:]...)
}
}
if len(s) == 1 && Isconst(s[0], CTSTR) {
n.Op = OLITERAL
n.SetVal(s[0].Val())
} else {
n.List.Set(s)
}
case OCAP, OLEN:
switch nl.Type.Etype {
case TSTRING:
if Isconst(nl, CTSTR) {
setintconst(n, int64(len(nl.Val().U.(string))))
}
case TARRAY:
if !hascallchan(nl) {
setintconst(n, nl.Type.NumElem())
}
}
case OALIGNOF, OOFFSETOF, OSIZEOF:
setintconst(n, evalunsafe(n))
case OREAL, OIMAG:
if nl.Op == OLITERAL {
var re, im *Mpflt
switch u := nl.Val().U.(type) {
case *Mpint:
re = newMpflt()
re.SetInt(u)
// im = 0
case *Mpflt:
re = u
// im = 0
case *Mpcplx:
re = &u.Real
im = &u.Imag
default:
Fatalf("impossible")
}
if n.Op == OIMAG {
if im == nil {
im = newMpflt()
}
re = im
}
setconst(n, Val{re})
}
case OCOMPLEX:
if nl == nil || nr == nil {
// TODO(mdempsky): Remove after early OAS2FUNC rewrite CL lands.
break
}
if nl.Op == OLITERAL && nr.Op == OLITERAL {
// make it a complex literal
c := newMpcmplx()
c.Real.Set(toflt(nl.Val()).U.(*Mpflt))
c.Imag.Set(toflt(nr.Val()).U.(*Mpflt))
setconst(n, Val{c})
}
}
}
func match(x, y Val) (Val, Val) {
switch {
case x.Ctype() == CTCPLX || y.Ctype() == CTCPLX:
return tocplx(x), tocplx(y)
case x.Ctype() == CTFLT || y.Ctype() == CTFLT:
return toflt(x), toflt(y)
}
// Mixed int/rune are fine.
return x, y
}
func compareOp(x Val, op Op, y Val) bool {
x, y = match(x, y)
switch x.Ctype() {
case CTNIL:
_, _ = x.U.(*NilVal), y.U.(*NilVal) // assert dynamic types match
switch op {
case OEQ:
return true
case ONE:
return false
}
case CTBOOL:
x, y := x.U.(bool), y.U.(bool)
switch op {
case OEQ:
return x == y
case ONE:
return x != y
}
case CTINT, CTRUNE:
x, y := x.U.(*Mpint), y.U.(*Mpint)
return cmpZero(x.Cmp(y), op)
case CTFLT:
x, y := x.U.(*Mpflt), y.U.(*Mpflt)
return cmpZero(x.Cmp(y), op)
case CTCPLX:
x, y := x.U.(*Mpcplx), y.U.(*Mpcplx)
eq := x.Real.Cmp(&y.Real) == 0 && x.Imag.Cmp(&y.Imag) == 0
switch op {
case OEQ:
return eq
case ONE:
return !eq
}
case CTSTR:
x, y := x.U.(string), y.U.(string)
switch op {
case OEQ:
return x == y
case ONE:
return x != y
case OLT:
return x < y
case OLE:
return x <= y
case OGT:
return x > y
case OGE:
return x >= y
}
}
Fatalf("compareOp: bad comparison: %v %v %v", x, op, y)
panic("unreachable")
}
func cmpZero(x int, op Op) bool {
switch op {
case OEQ:
return x == 0
case ONE:
return x != 0
case OLT:
return x < 0
case OLE:
return x <= 0
case OGT:
return x > 0
case OGE:
return x >= 0
}
Fatalf("cmpZero: want comparison operator, got %v", op)
panic("unreachable")
}
func binaryOp(x Val, op Op, y Val) Val {
x, y = match(x, y)
Outer:
switch x.Ctype() {
case CTBOOL:
x, y := x.U.(bool), y.U.(bool)
switch op {
case OANDAND:
return Val{U: x && y}
case OOROR:
return Val{U: x || y}
}
case CTINT, CTRUNE:
x, y := x.U.(*Mpint), y.U.(*Mpint)
u := new(Mpint)
u.Rune = x.Rune || y.Rune
u.Set(x)
switch op {
case OADD:
u.Add(y)
case OSUB:
u.Sub(y)
case OMUL:
u.Mul(y)
case ODIV:
if y.CmpInt64(0) == 0 {
yyerror("division by zero")
return Val{}
}
u.Quo(y)
case OMOD:
if y.CmpInt64(0) == 0 {
yyerror("division by zero")
return Val{}
}
u.Rem(y)
case OOR:
u.Or(y)
case OAND:
u.And(y)
case OANDNOT:
u.AndNot(y)
case OXOR:
u.Xor(y)
default:
break Outer
}
return Val{U: u}
case CTFLT:
x, y := x.U.(*Mpflt), y.U.(*Mpflt)
u := newMpflt()
u.Set(x)
switch op {
case OADD:
u.Add(y)
case OSUB:
u.Sub(y)
case OMUL:
u.Mul(y)
case ODIV:
if y.CmpFloat64(0) == 0 {
yyerror("division by zero")
return Val{}
}
u.Quo(y)
case OMOD, OOR, OAND, OANDNOT, OXOR:
// TODO(mdempsky): Move to typecheck; see #31060.
yyerror("invalid operation: operator %v not defined on untyped float", op)
return Val{}
default:
break Outer
}
return Val{U: u}
case CTCPLX:
x, y := x.U.(*Mpcplx), y.U.(*Mpcplx)
u := newMpcmplx()
u.Real.Set(&x.Real)
u.Imag.Set(&x.Imag)
switch op {
case OADD:
u.Real.Add(&y.Real)
u.Imag.Add(&y.Imag)
case OSUB:
u.Real.Sub(&y.Real)
u.Imag.Sub(&y.Imag)
case OMUL:
u.Mul(y)
case ODIV:
if !u.Div(y) {
yyerror("complex division by zero")
return Val{}
}
case OMOD, OOR, OAND, OANDNOT, OXOR:
// TODO(mdempsky): Move to typecheck; see #31060.
yyerror("invalid operation: operator %v not defined on untyped complex", op)
return Val{}
default:
break Outer
}
return Val{U: u}
}
Fatalf("binaryOp: bad operation: %v %v %v", x, op, y)
panic("unreachable")
}
func unaryOp(op Op, x Val, t *types.Type) Val {
switch op {
case OPLUS:
switch x.Ctype() {
case CTINT, CTRUNE, CTFLT, CTCPLX:
return x
}
case ONEG:
switch x.Ctype() {
case CTINT, CTRUNE:
x := x.U.(*Mpint)
u := new(Mpint)
u.Rune = x.Rune
u.Set(x)
u.Neg()
return Val{U: u}
case CTFLT:
x := x.U.(*Mpflt)
u := newMpflt()
u.Set(x)
u.Neg()
return Val{U: u}
case CTCPLX:
x := x.U.(*Mpcplx)
u := newMpcmplx()
u.Real.Set(&x.Real)
u.Imag.Set(&x.Imag)
u.Real.Neg()
u.Imag.Neg()
return Val{U: u}
}
case OBITNOT:
switch x.Ctype() {
case CTINT, CTRUNE:
x := x.U.(*Mpint)
u := new(Mpint)
u.Rune = x.Rune
if t.IsSigned() || t.IsUntyped() {
// Signed values change sign.
u.SetInt64(-1)
} else {
// Unsigned values invert their bits.
u.Set(maxintval[t.Etype])
}
u.Xor(x)
return Val{U: u}
case CTFLT:
// TODO(mdempsky): Move to typecheck; see #31060.
yyerror("invalid operation: operator %v not defined on untyped float", op)
return Val{}
case CTCPLX:
// TODO(mdempsky): Move to typecheck; see #31060.
yyerror("invalid operation: operator %v not defined on untyped complex", op)
return Val{}
}
case ONOT:
return Val{U: !x.U.(bool)}
}
Fatalf("unaryOp: bad operation: %v %v", op, x)
panic("unreachable")
}
func shiftOp(x Val, op Op, y Val) Val {
if x.Ctype() != CTRUNE {
x = toint(x)
}
y = toint(y)
u := new(Mpint)
u.Set(x.U.(*Mpint))
u.Rune = x.U.(*Mpint).Rune
switch op {
case OLSH:
u.Lsh(y.U.(*Mpint))
case ORSH:
u.Rsh(y.U.(*Mpint))
default:
Fatalf("shiftOp: bad operator: %v", op)
panic("unreachable")
}
return Val{U: u}
}
// setconst rewrites n as an OLITERAL with value v.
func setconst(n *Node, v Val) {
// If constant folding failed, mark n as broken and give up.
if v.U == nil {
n.Type = nil
return
}
// Ensure n.Orig still points to a semantically-equivalent
// expression after we rewrite n into a constant.
if n.Orig == n {
n.Orig = n.sepcopy()
}
*n = Node{
Op: OLITERAL,
Pos: n.Pos,
Orig: n.Orig,
Type: n.Type,
Xoffset: BADWIDTH,
}
n.SetVal(v)
// Check range.
lno := setlineno(n)
overflow(v, n.Type)
lineno = lno
// Truncate precision for non-ideal float.
if v.Ctype() == CTFLT && n.Type.Etype != TIDEAL {
n.SetVal(Val{truncfltlit(v.U.(*Mpflt), n.Type)})
}
}
func setboolconst(n *Node, v bool) {
setconst(n, Val{U: v})
}
func setintconst(n *Node, v int64) {
u := new(Mpint)
u.SetInt64(v)
setconst(n, Val{u})
}
// nodlit returns a new untyped constant with value v.
func nodlit(v Val) *Node {
n := nod(OLITERAL, nil, nil)
n.SetVal(v)
switch v.Ctype() {
default:
Fatalf("nodlit ctype %d", v.Ctype())
case CTSTR:
n.Type = types.Idealstring
case CTBOOL:
n.Type = types.Idealbool
case CTINT, CTRUNE, CTFLT, CTCPLX:
n.Type = types.Types[TIDEAL]
case CTNIL:
n.Type = types.Types[TNIL]
}
return n
}
// idealkind returns a constant kind like consttype
// but for an arbitrary "ideal" (untyped constant) expression.
func idealkind(n *Node) Ctype {
if n == nil || !n.Type.IsUntyped() {
return CTxxx
}
switch n.Op {
default:
return CTxxx
case OLITERAL:
return n.Val().Ctype()
// numeric kinds.
case OADD,
OAND,
OANDNOT,
OBITNOT,
ODIV,
ONEG,
OMOD,
OMUL,
OSUB,
OXOR,
OOR,
OPLUS:
k1 := idealkind(n.Left)
k2 := idealkind(n.Right)
if k1 > k2 {
return k1
} else {
return k2
}
case OREAL, OIMAG:
return CTFLT
case OCOMPLEX:
return CTCPLX
case OADDSTR:
return CTSTR
case OANDAND,
OEQ,
OGE,
OGT,
OLE,
OLT,
ONE,
ONOT,
OOROR:
return CTBOOL
// shifts (beware!).
case OLSH, ORSH:
return idealkind(n.Left)
}
}
// The result of defaultlit MUST be assigned back to n, e.g.
// n.Left = defaultlit(n.Left, t)
func defaultlit(n *Node, t *types.Type) *Node {
return defaultlitreuse(n, t, noReuse)
}
// The result of defaultlitreuse MUST be assigned back to n, e.g.
// n.Left = defaultlitreuse(n.Left, t, reuse)
func defaultlitreuse(n *Node, t *types.Type, reuse canReuseNode) *Node {
if n == nil || !n.Type.IsUntyped() {
return n
}
if n.Op == OLITERAL && !reuse {
n = n.rawcopy()
reuse = true
}
lno := setlineno(n)
ctype := idealkind(n)
var t1 *types.Type
switch ctype {
default:
if t != nil {
return convlit(n, t)
}
switch n.Val().Ctype() {
case CTNIL:
lineno = lno
if !n.Diag() {
yyerror("use of untyped nil")
n.SetDiag(true)
}
n.Type = nil
case CTSTR:
t1 := types.Types[TSTRING]
n = convlit1(n, t1, false, reuse)
default:
yyerror("defaultlit: unknown literal: %v", n)
}
lineno = lno
return n
case CTxxx:
Fatalf("defaultlit: idealkind is CTxxx: %+v", n)
case CTBOOL:
t1 := types.Types[TBOOL]
if t != nil && t.IsBoolean() {
t1 = t
}
n = convlit1(n, t1, false, reuse)
lineno = lno
return n
case CTINT:
t1 = types.Types[TINT]
case CTRUNE:
t1 = types.Runetype
case CTFLT:
t1 = types.Types[TFLOAT64]
case CTCPLX:
t1 = types.Types[TCOMPLEX128]
}
// Note: n.Val().Ctype() can be CTxxx (not a constant) here
// in the case of an untyped non-constant value, like 1<<i.
v1 := n.Val()
if t != nil {
if t.IsInteger() {
t1 = t
v1 = toint(n.Val())
} else if t.IsFloat() {
t1 = t
v1 = toflt(n.Val())
} else if t.IsComplex() {
t1 = t
v1 = tocplx(n.Val())
}
if n.Val().Ctype() != CTxxx {
n.SetVal(v1)
}
}
if n.Val().Ctype() != CTxxx {
overflow(n.Val(), t1)
}
n = convlit1(n, t1, false, reuse)
lineno = lno
return n
}
// defaultlit on both nodes simultaneously;
// if they're both ideal going in they better
// get the same type going out.
// force means must assign concrete (non-ideal) type.
// The results of defaultlit2 MUST be assigned back to l and r, e.g.
// n.Left, n.Right = defaultlit2(n.Left, n.Right, force)
func defaultlit2(l *Node, r *Node, force bool) (*Node, *Node) {
if l.Type == nil || r.Type == nil {
return l, r
}
if !l.Type.IsUntyped() {
r = convlit(r, l.Type)
return l, r
}
if !r.Type.IsUntyped() {
l = convlit(l, r.Type)
return l, r
}
if !force {
return l, r
}
if l.Type.IsBoolean() {
l = convlit(l, types.Types[TBOOL])
r = convlit(r, types.Types[TBOOL])
}
lkind := idealkind(l)
rkind := idealkind(r)
if lkind == CTCPLX || rkind == CTCPLX {
l = convlit(l, types.Types[TCOMPLEX128])
r = convlit(r, types.Types[TCOMPLEX128])
return l, r
}
if lkind == CTFLT || rkind == CTFLT {
l = convlit(l, types.Types[TFLOAT64])
r = convlit(r, types.Types[TFLOAT64])
return l, r
}
if lkind == CTRUNE || rkind == CTRUNE {
l = convlit(l, types.Runetype)
r = convlit(r, types.Runetype)
return l, r
}
l = convlit(l, types.Types[TINT])
r = convlit(r, types.Types[TINT])
return l, r
}
// strlit returns the value of a literal string Node as a string.
func strlit(n *Node) string {
return n.Val().U.(string)
}
// TODO(gri) smallintconst is only used in one place - can we used indexconst?
func smallintconst(n *Node) bool {
if n.Op == OLITERAL && Isconst(n, CTINT) && n.Type != nil {
switch simtype[n.Type.Etype] {
case TINT8,
TUINT8,
TINT16,
TUINT16,
TINT32,
TUINT32,
TBOOL:
return true
case TIDEAL, TINT64, TUINT64, TPTR:
v, ok := n.Val().U.(*Mpint)
if ok && v.Cmp(minintval[TINT32]) >= 0 && v.Cmp(maxintval[TINT32]) <= 0 {
return true
}
}
}
return false
}
// indexconst checks if Node n contains a constant expression
// representable as a non-negative int and returns its value.
// If n is not a constant expression, not representable as an
// integer, or negative, it returns -1. If n is too large, it
// returns -2.
func indexconst(n *Node) int64 {
if n.Op != OLITERAL {
return -1
}
v := toint(n.Val()) // toint returns argument unchanged if not representable as an *Mpint
vi, ok := v.U.(*Mpint)
if !ok || vi.CmpInt64(0) < 0 {
return -1
}
if vi.Cmp(maxintval[TINT]) > 0 {
return -2
}
return vi.Int64()
}
// isGoConst reports whether n is a Go language constant (as opposed to a
// compile-time constant).
//
// Expressions derived from nil, like string([]byte(nil)), while they
// may be known at compile time, are not Go language constants.
func (n *Node) isGoConst() bool {
return n.Op == OLITERAL && n.Val().Ctype() != CTNIL
}
func hascallchan(n *Node) bool {
if n == nil {
return false
}
switch n.Op {
case OAPPEND,
OCALL,
OCALLFUNC,
OCALLINTER,
OCALLMETH,
OCAP,
OCLOSE,
OCOMPLEX,
OCOPY,
ODELETE,
OIMAG,
OLEN,
OMAKE,
ONEW,
OPANIC,
OPRINT,
OPRINTN,
OREAL,
ORECOVER,
ORECV:
return true
}
if hascallchan(n.Left) || hascallchan(n.Right) {
return true
}
for _, n1 := range n.List.Slice() {
if hascallchan(n1) {
return true
}
}
for _, n2 := range n.Rlist.Slice() {
if hascallchan(n2) {
return true
}
}
return false
}
// A constSet represents a set of Go constant expressions.
type constSet struct {
m map[constSetKey]*Node
}
type constSetKey struct {
typ *types.Type
val interface{}
}
// add adds constant expressions to s. If a constant expression of
// equal value and identical type has already been added, then that
// type expression is returned. Otherwise, add returns nil.
//
// add also returns nil if n is not a Go constant expression.
//
// n must not be an untyped constant.
func (s *constSet) add(n *Node) *Node {
if n.Op == OCONVIFACE && n.Implicit() {
n = n.Left
}
if !n.isGoConst() {
return nil
}
if n.Type.IsUntyped() {
Fatalf("%v is untyped", n)
}
// Consts are only duplicates if they have the same value and
// identical types.
//
// In general, we have to use types.Identical to test type
// identity, because == gives false negatives for anonymous
// types and the byte/uint8 and rune/int32 builtin type
// aliases. However, this is not a problem here, because
// constant expressions are always untyped or have a named
// type, and we explicitly handle the builtin type aliases
// below.
//
// This approach may need to be revisited though if we fix
// #21866 by treating all type aliases like byte/uint8 and
// rune/int32.
typ := n.Type
switch typ {
case types.Bytetype:
typ = types.Types[TUINT8]
case types.Runetype:
typ = types.Types[TINT32]
}
k := constSetKey{typ, n.Val().Interface()}
if s.m == nil {
s.m = make(map[constSetKey]*Node)
}
old, dup := s.m[k]
if !dup {
s.m[k] = n
}
return old
}
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