cmd/compile: add support for a go:noinline directive

Some tests need to disable inlining of a function.  It's currently done
in one of a few ways (adding a function call, an empty switch, or a
defer).  Add support for a less fragile 'go:noinline' directive that
prevents inlining.

Fixes #12312

Change-Id: Ife444e13361b4a927709d81aa41e448f32eec8d4
Reviewed-on: https://go-review.googlesource.com/13911
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/test/inline.go b/test/inline.go
index 54f7b3efb1..fb20fab329 100644
--- a/test/inline.go
+++ b/test/inline.go
@@ -22,3 +22,12 @@ func add1(p unsafe.Pointer, x uintptr) unsafe.Pointer { // ERROR "can inline add
 func f(x *byte) *byte { // ERROR "can inline f" "leaking param: x to result"
 	return add2(x, 1) // ERROR "inlining call to add2" "inlining call to add1"
 }
+
+//go:noinline
+func g(x int) int {
+	return x + 1
+}
+
+func h(x int) int { // ERROR "can inline h"
+	return x + 2
+}