cmd/compile/internal/types2: export TypeHash, return value without blanks
Change the typeWriter to produce blank-free hashes where easily possible
if used as a type hasher, and replace remaining blanks with '#' is needed.
Exported Environment.TypeHash for use by the compiler.
Change-Id: Icbd364c207f9c139a7a1844bb695512a0c56a4e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/349990
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
diff --git a/src/cmd/compile/internal/types2/environment.go b/src/cmd/compile/internal/types2/environment.go
index 816139b..5ef8855 100644
--- a/src/cmd/compile/internal/types2/environment.go
+++ b/src/cmd/compile/internal/types2/environment.go
@@ -5,6 +5,7 @@
import (
"bytes"
+ "strings"
"sync"
)
@@ -28,11 +29,11 @@
}
}
-// typeHash returns a string representation of typ, which can be used as an exact
+// TypeHash returns a string representation of typ, which can be used as an exact
// type hash: types that are identical produce identical string representations.
// If typ is a *Named type and targs is not empty, typ is printed as if it were
-// instantiated with targs.
-func (env *Environment) typeHash(typ Type, targs []Type) string {
+// instantiated with targs. The result is guaranteed to not contain blanks (" ").
+func (env *Environment) TypeHash(typ Type, targs []Type) string {
assert(env != nil)
assert(typ != nil)
var buf bytes.Buffer
@@ -56,7 +57,7 @@
}
}
- return buf.String()
+ return strings.Replace(buf.String(), " ", "#", -1) // ReplaceAll is not available in Go1.4
}
// typeForHash returns the recorded type for the type hash h, if it exists.
diff --git a/src/cmd/compile/internal/types2/instantiate.go b/src/cmd/compile/internal/types2/instantiate.go
index 469ceea..fdb87e7 100644
--- a/src/cmd/compile/internal/types2/instantiate.go
+++ b/src/cmd/compile/internal/types2/instantiate.go
@@ -108,7 +108,7 @@
case *Named:
var h string
if env != nil {
- h = env.typeHash(t, targs)
+ h = env.TypeHash(t, targs)
// typ may already have been instantiated with identical type arguments. In
// that case, re-use the existing instance.
if named := env.typeForHash(h, nil); named != nil {
diff --git a/src/cmd/compile/internal/types2/named.go b/src/cmd/compile/internal/types2/named.go
index 99410ae..46487d1 100644
--- a/src/cmd/compile/internal/types2/named.go
+++ b/src/cmd/compile/internal/types2/named.go
@@ -262,7 +262,7 @@
// instance in the process of expansion.
env = NewEnvironment()
}
- h := env.typeHash(n.orig, n.targs.list())
+ h := env.TypeHash(n.orig, n.targs.list())
// add the instance to the environment to avoid infinite recursion.
// addInstance may return a different, existing instance, but we
// shouldn't return that instance from expand.
diff --git a/src/cmd/compile/internal/types2/subst.go b/src/cmd/compile/internal/types2/subst.go
index 4627dd3..8d96494 100644
--- a/src/cmd/compile/internal/types2/subst.go
+++ b/src/cmd/compile/internal/types2/subst.go
@@ -211,7 +211,7 @@
}
// before creating a new named type, check if we have this one already
- h := subst.env.typeHash(t.orig, newTArgs)
+ h := subst.env.TypeHash(t.orig, newTArgs)
dump(">>> new type hash: %s", h)
if named := subst.env.typeForHash(h, nil); named != nil {
dump(">>> found %s", named)
diff --git a/src/cmd/compile/internal/types2/typestring.go b/src/cmd/compile/internal/types2/typestring.go
index 39ba278..71da37c 100644
--- a/src/cmd/compile/internal/types2/typestring.go
+++ b/src/cmd/compile/internal/types2/typestring.go
@@ -8,7 +8,6 @@
import (
"bytes"
- "fmt"
"strconv"
"unicode/utf8"
)
@@ -83,14 +82,29 @@
return &typeWriter{buf, make(map[Type]bool), nil, env}
}
-func (w *typeWriter) byte(b byte) { w.buf.WriteByte(b) }
-func (w *typeWriter) string(s string) { w.buf.WriteString(s) }
-func (w *typeWriter) writef(format string, args ...interface{}) { fmt.Fprintf(w.buf, format, args...) }
+func (w *typeWriter) byte(b byte) {
+ if w.env != nil {
+ if b == ' ' {
+ b = '#'
+ }
+ w.buf.WriteByte(b)
+ return
+ }
+ w.buf.WriteByte(b)
+ if b == ',' || b == ';' {
+ w.buf.WriteByte(' ')
+ }
+}
+
+func (w *typeWriter) string(s string) {
+ w.buf.WriteString(s)
+}
+
func (w *typeWriter) error(msg string) {
if w.env != nil {
panic(msg)
}
- w.string("<" + msg + ">")
+ w.buf.WriteString("<" + msg + ">")
}
func (w *typeWriter) typ(typ Type) {
@@ -117,7 +131,9 @@
w.string(t.name)
case *Array:
- w.writef("[%d]", t.len)
+ w.byte('[')
+ w.string(strconv.FormatInt(t.len, 10))
+ w.byte(']')
w.typ(t.elem)
case *Slice:
@@ -128,7 +144,7 @@
w.string("struct{")
for i, f := range t.fields {
if i > 0 {
- w.string("; ")
+ w.byte(';')
}
// This doesn't do the right thing for embedded type
// aliases where we should print the alias name, not
@@ -139,7 +155,11 @@
}
w.typ(f.typ)
if tag := t.Tag(i); tag != "" {
- w.writef(" %q", tag)
+ w.byte(' ')
+ // TODO(gri) If tag contains blanks, replacing them with '#'
+ // in Environment.TypeHash may produce another tag
+ // accidentally.
+ w.string(strconv.Quote(tag))
}
}
w.byte('}')
@@ -177,7 +197,7 @@
first := true
for _, m := range t.methods {
if !first {
- w.string("; ")
+ w.byte(';')
}
first = false
w.string(m.name)
@@ -185,7 +205,7 @@
}
for _, typ := range t.embeddeds {
if !first {
- w.string("; ")
+ w.byte(';')
}
first = false
w.typ(typ)
@@ -279,7 +299,7 @@
w.byte('[')
for i, typ := range list {
if i > 0 {
- w.string(", ")
+ w.byte(',')
}
w.typ(typ)
}
@@ -303,7 +323,7 @@
w.byte(' ')
w.typ(prev)
}
- w.string(", ")
+ w.byte(',')
}
prev = tpar.bound
w.typ(tpar)
@@ -327,7 +347,7 @@
if tup != nil {
for i, v := range tup.vars {
if i > 0 {
- w.string(", ")
+ w.byte(',')
}
// parameter names are ignored for type identity and thus type hashes
if w.env == nil && v.name != "" {
