[patch] 38_all_gcov-TOPN-PR96913.patch

38_all_gcov-TOPN-PR96913.patch (text/plain), 1.39 KB, created by Sergei Trofimovich (RETIRED) on 2020-09-06 11:56:21 UTC

https://gcc.gnu.org/PR96913
https://gcc.gnu.org/PR96394
https://bugs.gentoo.org/734006

From ae887148e112e018bec0bab5bc15e53f2225037a Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <[e-mail]>
Date: Sun, 6 Sep 2020 12:13:54 +0100
Subject: [PATCH] gcov: fix TOPN streaming from shared libraries

Before the change gcc did not stream correctly TOPN counters
if counters belonged to a non-local shared object.

As a result zero-section optimization generated TOPN sections
in a form not recognizable by '__gcov_merge_topn'.

The problem happens because in a case of multiple shared objects
'__gcov_merge_topn' function is present in address space multiple
times (once per each object).

The fix is to never rely on function address and predicate on TOPN
counter types.

libgcc/ChangeLog:

	PR gcov-profile/96913
	* libgcov-driver.c (write_one_data): Avoid function pointer
	comparison in TOP streaming decision.
---
 libgcc/libgcov-driver.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/libgcc/libgcov-driver.c
+++ b/libgcc/libgcov-driver.c
@@ -242,7 +242,7 @@ prune_counters (struct gcov_info *gi)
 	  if (gi->merge[j] == NULL)
 	    continue;
 
-	  if (gi->merge[j] == __gcov_merge_topn)
+	  if (j == GCOV_COUNTER_V_TOPN || j == GCOV_COUNTER_V_INDIR)
 	    {
 	      gcc_assert (!(ci->num % GCOV_TOPN_VALUES_COUNTERS));
 	      for (unsigned k = 0; k < (ci->num / GCOV_TOPN_VALUES_COUNTERS);