GCOV: document behavior of -fkeep-{static,inline}-functions (PR gcov-profile/82633).

2017-10-31  Martin Liska  <mliska@suse.cz>

	PR gcov-profile/82633
	* doc/gcov.texi: Document -fkeep-{static,inline}-functions and
	their interaction with GCOV infrastructure.
	* configure.ac: Add -fkeep-{inline,static}-functions to
	coverage_flags.
	* configure: Regenerate.

From-SVN: r254257

gcc/ChangeLog

+2017-10-31  Martin Liska  <mliska@suse.cz>
+
+	PR gcov-profile/82633
+	* doc/gcov.texi: Document -fkeep-{static,inline}-functions and
+	their interaction with GCOV infrastructure.
+	* configure.ac: Add -fkeep-{inline,static}-functions to
+	coverage_flags.
+	* configure: Regenerate.
+
 2017-10-31  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/82772

gcc/configure

@@ -7321,10 +7321,10 @@ fi
 if test "${enable_coverage+set}" = set; then :
   enableval=$enable_coverage; case "${enableval}" in
   yes|noopt)
-    coverage_flags="-fprofile-arcs -ftest-coverage -frandom-seed=\$@ -O0"
+    coverage_flags="-fprofile-arcs -ftest-coverage -frandom-seed=\$@ -O0 -fkeep-inline-functions -fkeep-static-functions"
     ;;
   opt)
-    coverage_flags="-fprofile-arcs -ftest-coverage -frandom-seed=\$@ -O2"
+    coverage_flags="-fprofile-arcs -ftest-coverage -frandom-seed=\$@ -O2 -fkeep-inline-functions -fkeep-static-functions"
     ;;
   no)
     # a.k.a. --disable-coverage

gcc/configure.ac

@@ -728,10 +728,10 @@ AC_ARG_ENABLE(coverage,
 		 default is noopt])],
 [case "${enableval}" in
   yes|noopt)
-    coverage_flags="-fprofile-arcs -ftest-coverage -frandom-seed=\$@ -O0"
+    coverage_flags="-fprofile-arcs -ftest-coverage -frandom-seed=\$@ -O0 -fkeep-inline-functions -fkeep-static-functions"
     ;;
   opt)
-    coverage_flags="-fprofile-arcs -ftest-coverage -frandom-seed=\$@ -O2"
+    coverage_flags="-fprofile-arcs -ftest-coverage -frandom-seed=\$@ -O2 -fkeep-inline-functions -fkeep-static-functions"
     ;;
   no)
     # a.k.a. --disable-coverage

gcc/doc/gcov.texi

@@ -328,6 +328,13 @@ handlers, respectively. Given @samp{-a} option, unexecuted blocks are
 marked @samp{$$$$$} or @samp{%%%%%}, depending on whether a basic block
 is reachable via non-exceptional or exceptional paths.
 
+Note that GCC can completely remove the bodies of functions that are
+not needed -- for instance if they are inlined everywhere.  Such functions
+are marked with @samp{-}, which can be confusing.
+Use the @option{-fkeep-inline-functions} and @option{-fkeep-static-functions}
+options to retain these functions and
+allow gcov to properly show their @var{execution_count}.
+
 Some lines of information at the start have @var{line_number} of zero.
 These preamble lines are of the form