cmd/compile: turn off jump tables when spectre retpolines are on

Fixes #57097

Change-Id: I6ab659abbca1ae0ac8710674d39aec116fab0baa
Reviewed-on: https://go-review.googlesource.com/c/go/+/455336
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/test/codegen/retpoline.go b/test/codegen/retpoline.go
index 15d6a26615..a04a005e2e 100644
--- a/test/codegen/retpoline.go
+++ b/test/codegen/retpoline.go
@@ -12,3 +12,31 @@ func CallInterface(x interface{ M() }) {
 	// amd64:`CALL\truntime.retpoline`
 	x.M()
 }
+
+// Check to make sure that jump tables are disabled
+// when retpoline is on. See issue 57097.
+func noJumpTables(x int) int {
+	switch x {
+	case 0:
+		return 0
+	case 1:
+		return 1
+	case 2:
+		return 2
+	case 3:
+		return 3
+	case 4:
+		return 4
+	case 5:
+		return 5
+	case 6:
+		return 6
+	case 7:
+		return 7
+	case 8:
+		return 8
+	case 9:
+		return 9
+	}
+	return 10
+}