cmd/gc: fix handling of struct padding in hash/eq.
The test case of issue 4585 was not passing due to
miscalculation of memequal args, and the previous fix
does not handle padding at the end of a struct.
Handling of padding at end of structs also fixes the case
of [n]T where T is such a padded struct.
Fixes #4585.
(again)
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7133059
diff --git a/test/fixedbugs/issue4585.go b/test/fixedbugs/issue4585.go
index 558bd1e..ad1242d 100644
--- a/test/fixedbugs/issue4585.go
+++ b/test/fixedbugs/issue4585.go
@@ -32,6 +32,20 @@
A, _, B int32
}
+// V has padding but not on the first field.
+type V struct {
+ A1, A2, A3 int32
+ B int16
+ C int32
+}
+
+// W has padding at the end.
+type W struct {
+ A1, A2, A3 int32
+ B int32
+ C int8
+}
+
func test1() {
var a, b U
m := make(map[U]int)
@@ -84,8 +98,54 @@
}
}
+func test4() {
+ var a, b V
+ m := make(map[V]int)
+
+ copy((*[20]byte)(unsafe.Pointer(&a))[:], "Hello World, Gopher!")
+ a.A1, a.A2, a.A3, a.B, a.C = 1, 2, 3, 4, 5
+ b.A1, b.A2, b.A3, b.B, b.C = 1, 2, 3, 4, 5
+
+ if a != b {
+ panic("broken equality: a != b")
+ }
+
+ m[a] = 1
+ m[b] = 2
+ if len(m) == 2 {
+ panic("broken hash: len(m) == 2")
+ }
+ if m[a] != 2 {
+ panic("m[a] != 2")
+ }
+}
+
+func test5() {
+ var a, b W
+ m := make(map[W]int)
+
+ copy((*[20]byte)(unsafe.Pointer(&a))[:], "Hello World, Gopher!")
+ a.A1, a.A2, a.A3, a.B, a.C = 1, 2, 3, 4, 5
+ b.A1, b.A2, b.A3, b.B, b.C = 1, 2, 3, 4, 5
+
+ if a != b {
+ panic("broken equality: a != b")
+ }
+
+ m[a] = 1
+ m[b] = 2
+ if len(m) == 2 {
+ panic("broken hash: len(m) == 2")
+ }
+ if m[a] != 2 {
+ panic("m[a] != 2")
+ }
+}
+
func main() {
test1()
test2()
test3()
+ test4()
+ test5()
}
