On May 31, 2018 8:51:59 AM GMT+02:00, Jakub Jelinek <ja...@redhat.com> wrote:
>Hi!
>
>We say in the documentation only supported body of naked functions
>is basic asm, anything else may but might not work. On the following
>testcase we end up with ICE, because the missing epilogue means the
>first
>partition is not separated from the second partition with a barrier and
>something before that.
>
>I think easiest is just not to partition such functions, for the really
>supported case it shouldn't make a difference anyway.
>
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Is naked an attribute that is specified for all targets? If so, OK. Otherwise
we may instead want to add a target hook for whether a function has a
prologue/epilogue?
Richard.
>2018-05-31 Jakub Jelinek <ja...@redhat.com>
>
> PR target/85984
> * bb-reorder.c (pass_partition_blocks::gate): Return false for
> functions with naked attribute.
>
> * gcc.target/i386/pr85984.c: New test.
>
>--- gcc/bb-reorder.c.jj 2018-05-09 20:12:28.399260557 +0200
>+++ gcc/bb-reorder.c 2018-05-30 16:01:12.113006870 +0200
>@@ -2928,8 +2928,8 @@ pass_partition_blocks::gate (function *f
> {
> /* The optimization to partition hot/cold basic blocks into separate
> sections of the .o file does not work well with linkonce or with
>- user defined section attributes. Don't call it if either case
>- arises. */
>+ user defined section attributes or with naked attribute. Don't
>call
>+ it if either case arises. */
> return (flag_reorder_blocks_and_partition
> && optimize
> /* See pass_reorder_blocks::gate. We should not partition if
>@@ -2937,6 +2937,7 @@ pass_partition_blocks::gate (function *f
> && optimize_function_for_speed_p (fun)
> && !DECL_COMDAT_GROUP (current_function_decl)
> && !lookup_attribute ("section", DECL_ATTRIBUTES (fun->decl))
>+ && !lookup_attribute ("naked", DECL_ATTRIBUTES (fun->decl))
> /* Workaround a bug in GDB where read_partial_die doesn't cope
> with DIEs with DW_AT_ranges, see PR81115. */
> && !(in_lto_p && MAIN_NAME_P (DECL_NAME (fun->decl))));
>--- gcc/testsuite/gcc.target/i386/pr85984.c.jj 2018-05-30
>16:08:24.951523398 +0200
>+++ gcc/testsuite/gcc.target/i386/pr85984.c 2018-05-30
>16:08:12.184508165 +0200
>@@ -0,0 +1,18 @@
>+/* PR target/85984 */
>+/* { dg-do compile } */
>+/* { dg-options "-O2" } */
>+
>+int foo (void);
>+
>+void __attribute__((naked))
>+bar (void)
>+{
>+ if (!foo ())
>+ __builtin_abort ();
>+}
>+
>+void
>+baz (void)
>+{
>+ bar ();
>+}
>
> Jakub
