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cmd/compile: simplify Eqtype

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Change-Id: I443f997ed53f965ef5b33734351ab8a07a09746b
Reviewed-on: https://go-review.googlesource.com/20213
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
This commit is contained in:
Matthew Dempsky 2016-03-04 01:53:54 -08:00
parent 132ebeac3f
commit 62e26e7511
1 changed files with 22 additions and 41 deletions
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63
src/cmd/compile/internal/gc/subr.go
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@ -705,32 +705,22 @@ func eqnote(a, b *string) bool {
return a == b || a != nil && b != nil && *a == *b
}
type TypePairList struct {
t1 *Type
t2 *Type
next *TypePairList
}
func onlist(l *TypePairList, t1 *Type, t2 *Type) bool {
for ; l != nil; l = l.next {
if (l.t1 == t1 && l.t2 == t2) || (l.t1 == t2 && l.t2 == t1) {
return true
}
}
return false
}
// Return 1 if t1 and t2 are identical, following the spec rules.
// Eqtype reports whether t1 and t2 are identical, following the spec rules.
//
// Any cyclic type must go through a named type, and if one is
// named, it is only identical to the other if they are the same
// pointer (t1 == t2), so there's no chance of chasing cycles
// ad infinitum, so no need for a depth counter.
func Eqtype(t1 *Type, t2 *Type) bool {
func Eqtype(t1, t2 *Type) bool {
return eqtype1(t1, t2, nil)
}
func eqtype1(t1 *Type, t2 *Type, assumed_equal *TypePairList) bool {
type typePair struct {
t1 *Type
t2 *Type
}
func eqtype1(t1, t2 *Type, assumedEqual map[typePair]struct{}) bool {
if t1 == t2 {
return true
}
@ -738,30 +728,24 @@ func eqtype1(t1 *Type, t2 *Type, assumed_equal *TypePairList) bool {
return false
}
if t1.Sym != nil || t2.Sym != nil {
// Special case: we keep byte and uint8 separate
// for error messages. Treat them as equal.
// Special case: we keep byte/uint8 and rune/int32
// separate for error messages. Treat them as equal.
switch t1.Etype {
case TUINT8:
if (t1 == Types[TUINT8] || t1 == bytetype) && (t2 == Types[TUINT8] || t2 == bytetype) {
return true
}
case TINT, TINT32:
if (t1 == Types[runetype.Etype] || t1 == runetype) && (t2 == Types[runetype.Etype] || t2 == runetype) {
return true
}
return (t1 == Types[TUINT8] || t1 == bytetype) && (t2 == Types[TUINT8] || t2 == bytetype)
case TINT32:
return (t1 == Types[TINT32] || t1 == runetype) && (t2 == Types[TINT32] || t2 == runetype)
default:
return false
}
return false
}
if onlist(assumed_equal, t1, t2) {
if assumedEqual == nil {
assumedEqual = make(map[typePair]struct{})
} else if _, ok := assumedEqual[typePair{t1, t2}]; ok {
return true
}
var l TypePairList
l.next = assumed_equal
l.t1 = t1
l.t2 = t2
assumedEqual[typePair{t1, t2}] = struct{}{}
switch t1.Etype {
case TINTER, TSTRUCT:
@ -771,7 +755,7 @@ func eqtype1(t1 *Type, t2 *Type, assumed_equal *TypePairList) bool {
if t1.Etype != TFIELD || t2.Etype != TFIELD {
Fatalf("struct/interface missing field: %v %v", t1, t2)
}
if t1.Sym != t2.Sym || t1.Embedded != t2.Embedded || !eqtype1(t1.Type, t2.Type, &l) || !eqnote(t1.Note, t2.Note) {
if t1.Sym != t2.Sym || t1.Embedded != t2.Embedded || !eqtype1(t1.Type, t2.Type, assumedEqual) || !eqnote(t1.Note, t2.Note) {
return false
}
}
@ -797,7 +781,7 @@ func eqtype1(t1 *Type, t2 *Type, assumed_equal *TypePairList) bool {
if ta.Etype != TFIELD || tb.Etype != TFIELD {
Fatalf("func struct missing field: %v %v", ta, tb)
}
if ta.Isddd != tb.Isddd || !eqtype1(ta.Type, tb.Type, &l) {
if ta.Isddd != tb.Isddd || !eqtype1(ta.Type, tb.Type, assumedEqual) {
return false
}
}
@ -823,10 +807,7 @@ func eqtype1(t1 *Type, t2 *Type, assumed_equal *TypePairList) bool {
}
}
if eqtype1(t1.Down, t2.Down, &l) && eqtype1(t1.Type, t2.Type, &l) {
return true
}
return false
return eqtype1(t1.Down, t2.Down, assumedEqual) && eqtype1(t1.Type, t2.Type, assumedEqual)
}
// Are t1 and t2 equal struct types when field names are ignored?