Hi,
On Mon, 7 Aug 2017, H.J. Lu wrote:
> >> This will break unwinders relying on frame pointers to exist on all
> >> functions, for which projects conciously forced a frame pointer with this
> >> option. I don't think we can simply override user specified explicit
> >> wishes in this way, presumably they had a reason to use it.
> >
> > Hm... yes, you are right.
> >
> > HJ, please revert the patch.
> >
>
> Is there a testcae? I'd like to add it.
Trivial change of your first example, see below.
> [hjl@gnu-tools-1 pr81736]$ clang -S -O2 -fno-omit-frame-pointer x.i
> [hjl@gnu-tools-1 pr81736]$ cat x.s
[... no frame ...]
> [hjl@gnu-tools-1 pr81736]$
>
> Does it mean clang is broken?
In my book, yes.
Ciao,
Michael.
Index: gcc/testsuite/gcc.target/i386/force-frame.c
===================================================================
--- gcc/testsuite/gcc.target/i386/force-frame.c (revision 0)
+++ gcc/testsuite/gcc.target/i386/force-frame.c (working copy)
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-omit-frame-pointer" } */
+
+int
+#ifndef __x86_64__
+__attribute__((regparm(3)))
+#endif
+foo (int i)
+{
+ return i;
+}
+
+/* The user wants a frame pointer. */
+/* { dg-final { scan-assembler "%\[re\]bp" } } */
