[tip:core/urgent] objtool: Support GCC 9 cold subfunction naming scheme

tip-bot for Josh Poimboeuf
2018-11-01T08:58:52Z

Commit-ID: bcb6fb5da77c2a228adf07cc9cb1a0c2aa2001c6
Gitweb: https://git.kernel.org/tip/bcb6fb5da77c2a228adf07cc9cb1a0c2aa2001c6
Author: Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Wed, 31 Oct 2018 21:57:30 -0500
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 1 Nov 2018 09:55:38 +0100

objtool: Support GCC 9 cold subfunction naming scheme

Starting with GCC 8, a lot of unlikely code was moved out of line to
"cold" subfunctions in .text.unlikely.

For example, the unlikely bits of:

irq_do_set_affinity()

are moved out to the following subfunction:

irq_do_set_affinity.cold.49()

Starting with GCC 9, the numbered suffix has been removed. So in the
above example, the cold subfunction is instead:

irq_do_set_affinity.cold()

Tweak the objtool subfunction detection logic so that it detects both
GCC 8 and GCC 9 naming schemes.

Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/015e9544b1f188d36a7f02fa31e9e95629aa5f50.1541040800.git.jpoimboe@redhat.com

---
tools/objtool/elf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 7ec85d567598..f8cef271dfc7 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -301,7 +301,7 @@ static int read_symbols(struct elf *elf)
if (sym->type != STT_FUNC)
continue;
sym->pfunc = sym->cfunc = sym;
- coldstr = strstr(sym->name, ".cold.");
+ coldstr = strstr(sym->name, ".cold");
if (!coldstr)
continue;