[release-branch.go1.22] cmd/compile: make jump table symbol static

The jump table symbol is accessed only from the function symbol
(in the same package), so it can be static. Also, if the function
is DUPOK and it is, somehow, compiled differently in two different
packages, the linker must choose the jump table symbol associated
to the function symbol it chose. Currently the jump table symbol
is DUPOK, so that is not guaranteed. Making it static will
guarantee that, as each copy of the function symbol refers to its
own jump table symbol.

Updates #65783.
Fixes #65818.

Change-Id: I27e051d01ef585d07700b75d4dfac5768f16441e
Reviewed-on: https://go-review.googlesource.com/c/go/+/565535
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
(cherry picked from commit 290835298067014e906c540d64dcaa706d66b2ce)
Reviewed-on: https://go-review.googlesource.com/c/go/+/566475

diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go
index fa4208228e78cbb49c16ecf5704b04d19ee068e5..bb09c6cddaae2d972a45a12cd02c7f938720cc68 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewrite.go
+++ b/src/cmd/compile/internal/ssa/rewrite.go
@@ -2131,8 +2131,8 @@ func logicFlags32(x int32) flagConstant {
 
 func makeJumpTableSym(b *Block) *obj.LSym {
        s := base.Ctxt.Lookup(fmt.Sprintf("%s.jump%d", b.Func.fe.Func().LSym.Name, b.ID))
-       s.Set(obj.AttrDuplicateOK, true)
-       s.Set(obj.AttrLocal, true)
+       // The jump table symbol is accessed only from the function symbol.
+       s.Set(obj.AttrStatic, true)
        return s
 }