cmd/compile: make duplicate anonymous interface output deterministic
Taking over CL 162240, the original CL hasn't been making progress.
I just took the parts that fix the immediate issue. I left the
signatslice changes out, I don't think they are necessary.
Fixes #30202
Change-Id: I5b347605f0841dd925d5a73150b8bf269fa82464
Reviewed-on: https://go-review.googlesource.com/c/go/+/183852
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go
index 9b26ba1..c2d9ba2 100644
--- a/src/cmd/compile/internal/gc/reflect.go
+++ b/src/cmd/compile/internal/gc/reflect.go
@@ -1659,7 +1659,17 @@
// they refer to byte or uint8, such as **byte vs **uint8,
// the types' ShortStrings can be identical.
// To preserve deterministic sort ordering, sort these by String().
- return a[i].regular < a[j].regular
+ if a[i].regular != a[j].regular {
+ return a[i].regular < a[j].regular
+ }
+ // Identical anonymous interfaces defined in different locations
+ // will be equal for the above checks, but different in DWARF output.
+ // Sort by source position to ensure deterministic order.
+ // See issues 27013 and 30202.
+ if a[i].t.Etype == types.TINTER && a[i].t.Methods().Len() > 0 {
+ return a[i].t.Methods().Index(0).Pos.Before(a[j].t.Methods().Index(0).Pos)
+ }
+ return false
}
func (a typesByString) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
diff --git a/src/cmd/compile/internal/gc/reproduciblebuilds_test.go b/src/cmd/compile/internal/gc/reproduciblebuilds_test.go
index 9173f80..59d1edb 100644
--- a/src/cmd/compile/internal/gc/reproduciblebuilds_test.go
+++ b/src/cmd/compile/internal/gc/reproduciblebuilds_test.go
@@ -18,6 +18,7 @@
tests := []string{
"issue20272.go",
"issue27013.go",
+ "issue30202.go",
}
testenv.MustHaveGoBuild(t)
@@ -38,7 +39,9 @@
defer os.Remove(tmp.Name())
defer tmp.Close()
for i := 0; i < iters; i++ {
- out, err := exec.Command(testenv.GoToolPath(t), "tool", "compile", "-o", tmp.Name(), filepath.Join("testdata", "reproducible", test)).CombinedOutput()
+ // Note: use -c 2 to expose any nondeterminism which is the result
+ // of the runtime scheduler.
+ out, err := exec.Command(testenv.GoToolPath(t), "tool", "compile", "-c", "2", "-o", tmp.Name(), filepath.Join("testdata", "reproducible", test)).CombinedOutput()
if err != nil {
t.Fatalf("failed to compile: %v\n%s", err, out)
}
diff --git a/src/cmd/compile/internal/gc/testdata/reproducible/issue30202.go b/src/cmd/compile/internal/gc/testdata/reproducible/issue30202.go
new file mode 100644
index 0000000..7b5de2c
--- /dev/null
+++ b/src/cmd/compile/internal/gc/testdata/reproducible/issue30202.go
@@ -0,0 +1,17 @@
+// Copyright 2019 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 p
+
+func A(x interface {
+ X() int
+}) int {
+ return x.X()
+}
+
+func B(x interface {
+ X() int
+}) int {
+ return x.X()
+}
