[PATCH] Test for profiling support (_mcount/gprof)

[Florian Weimer <fweimer at redhat dot com>]

The attached patch adds an integration test for gcc -pg, _mcount/gmon,
and gprof.

It passes on aarch64, ppc, ppc64, ppc64le, s390, s390x, x86_64, and on
i386 with the _mcount internal_function replacement applied.

The test is compiled with -pg and is linked against gcrt1.o, via the new
CRT-* makefile hook.  As far as I can tell, it is properly isolated from
system glibc (only GCC objects are picked up).

Thanks,
Florian

gmon: Add test for basic mcount/gprof functionality

2017-08-15  Florian Weimer  <fweimer@redhat.com>

	* gmon/Makefile (tests): Add tst-gmon.
	(CFLAGS-tst-gmon.c, LDFLAGS-tst-gmon, CRT-tst-gmon, tst-gmon-ENV):
	Set.
	(tests-special): Add tst-gmon-prof.out.
	(tst-gmon.out): Depend on clean-tst-gmon-data.
	(clean-tst-gmon-data, tst-gmon-gprof.out): New targets.
	* gmon/tst-gmon.c, gmon/tst-gmon-gprof.sh: New files.
	* Makeconfig (+link-before-libc): Add CRT-* hook to override the
	startup object.
	* aclocal.m4 (GPROF): Set and substitute.
	* config.amke.in (GPROF): Set.
	* configure: Regenerate.

diff --git a/Makeconfig b/Makeconfig
index 80aed2a987..19b559701a 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -465,7 +465,8 @@ else  # not build-pie-default
 +link-before-libc = $(CC) -nostdlib -nostartfiles -o $@ \
 	      $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \
 	      $(combreloc-LDFLAGS) $(relro-LDFLAGS) $(hashstyle-LDFLAGS) \
-	      $(addprefix $(csu-objpfx),$(start-installed-name)) \
+	      $(or $(CRT-$(@F)), $ \
+		$(addprefix $(csu-objpfx),$(start-installed-name))) \
 	      $(+preinit) $(+prector) \
 	      $(filter-out $(addprefix $(csu-objpfx),start.o \
 						     $(start-installed-name))\
diff --git a/aclocal.m4 b/aclocal.m4
index 69021558af..fe2a3713cc 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -121,6 +121,8 @@ OBJDUMP=`$CC -print-prog-name=objdump`
 AC_SUBST(OBJDUMP)
 OBJCOPY=`$CC -print-prog-name=objcopy`
 AC_SUBST(OBJCOPY)
+GPROF=`$CC -print-prog-name=gprof`
+AC_SUBST(GPROF)
 
 # Determine whether we are using GNU binutils.
 AC_CACHE_CHECK(whether $AS is GNU as, libc_cv_prog_as_gnu,
diff --git a/config.make.in b/config.make.in
index 7eff1daf6a..ea7a42cc19 100644
--- a/config.make.in
+++ b/config.make.in
@@ -120,6 +120,7 @@ BISON = @BISON@
 AUTOCONF = @AUTOCONF@
 OBJDUMP = @OBJDUMP@
 OBJCOPY = @OBJCOPY@
+GPROF = @GPROF@
 READELF = @READELF@
 
 # Installation tools.
diff --git a/configure b/configure
index e6a54d7841..5cb5210107 100755
--- a/configure
+++ b/configure
@@ -651,6 +651,7 @@ MSGFMT
 MAKE
 LD
 AS
+GPROF
 OBJCOPY
 OBJDUMP
 AR
@@ -4572,6 +4573,8 @@ OBJDUMP=`$CC -print-prog-name=objdump`
 
 OBJCOPY=`$CC -print-prog-name=objcopy`
 
+GPROF=`$CC -print-prog-name=gprof`
+
 
 # Determine whether we are using GNU binutils.
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $AS is GNU as" >&5
diff --git a/gmon/Makefile b/gmon/Makefile
index 6ff4cb0dfb..947e6b5905 100644
--- a/gmon/Makefile
+++ b/gmon/Makefile
@@ -27,7 +27,7 @@ routines := gmon mcount profil sprofil bb_init_func bb_exit_func prof-freq
 
 elide-routines.os = bb_init_func bb_exit_func
 
-tests	= tst-sprofil
+tests	= tst-sprofil tst-gmon
 ifeq ($(build-profile),yes)
 tests	+= tst-profile-static
 tests-static	+= tst-profile-static
@@ -38,6 +38,12 @@ endif
 # The mcount code won't work without a frame pointer.
 CFLAGS-mcount.c := -fno-omit-frame-pointer
 
+CFLAGS-tst-gmon.c := -pg
+LDFLAGS-tst-gmon := $(no-pie-ldflag)
+CRT-tst-gmon := $(csu-objpfx)gcrt1.o
+tst-gmon-ENV := GMON_OUT_PREFIX=$(objpfx)tst-gmon.data
+tests-special += $(objpfx)tst-gmon-gprof.out
+
 include ../Rules
 
 # We cannot compile mcount.c with -pg because that would
@@ -53,3 +59,13 @@ endif
 $(noprof:%=$(objpfx)%.op): %.op: %.o
 	rm -f $@
 	ln $< $@
+
+# GMON_OUTPUT_PREFIX only sets the output prefix.  The actual file
+# name contains the PID as well.
+$(objpfx)tst-gmon.out: clean-tst-gmon-data
+clean-tst-gmon-data:
+	rm -f $(objpfx)tst-gmon.data.*
+
+$(objpfx)tst-gmon-gprof.out: tst-gmon-gprof.sh $(objpfx)tst-gmon.out
+	$(SHELL) $< $(GPROF) $(objpfx)tst-gmon $(objpfx)tst-gmon.data.* > $@; \
+	$(evaluate-test)
diff --git a/gmon/tst-gmon-gprof.sh b/gmon/tst-gmon-gprof.sh
new file mode 100644
index 0000000000..b10a6e0763
--- /dev/null
+++ b/gmon/tst-gmon-gprof.sh
@@ -0,0 +1,59 @@
+#!/bin/sh
+# Check the output of gprof against a carfully crafted binary.
+# Copyright (C) 2017 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+LC_ALL=C
+export LC_ALL
+set -e
+exec 2>&1
+
+GPROF="$1"
+program="$2"
+data="$3"
+
+actual=$(mktemp)
+expected=$(mktemp)
+expected_dot=$(mktemp)
+cleanup () {
+    rm -f "$actual"
+    rm -f "$expected_dot"
+}
+trap cleanup 0
+
+cat > "$expected" <<EOF
+f1 2000
+f2 1000
+EOF
+
+# Special version for powerpc with function descriptors.
+cat > "$expected_dot" <<EOF
+.f1 2000
+.f2 1000
+EOF
+
+"$GPROF" -C "$program" "$data" \
+    | awk -F  '[(): ]' '/executions/{print $5, $8}' \
+    | sort > "$actual"
+
+if cmp -s "$actual" "$expected_dot" \
+   || diff -u --label expected "$expected" --label actual "$actual" ; then
+    echo "PASS"
+else
+    echo "FAIL"
+    exit 1
+fi
diff --git a/gmon/tst-gmon.c b/gmon/tst-gmon.c
new file mode 100644
index 0000000000..ce81aa41b8
--- /dev/null
+++ b/gmon/tst-gmon.c
@@ -0,0 +1,50 @@
+/* Test program for profiling information collection (_mcount/gprof).
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This program does not use the test harness because we want tight
+   control over the call graph.  */
+
+__attribute__ ((noinline, noclone, weak)) void
+f1 (void)
+{
+}
+
+__attribute__ ((noinline, noclone, weak)) void
+f2 (void)
+{
+  f1 ();
+  /* Prevent tail call.  */
+  asm volatile ("");
+}
+
+__attribute__ ((noinline, noclone, weak)) void
+f3 (int count)
+{
+  for (int i = 0; i < count; ++i)
+    {
+      f1 ();
+      f2 ();
+    }
+}
+
+int
+main (void)
+{
+  f3 (1000);
+  return 0;
+}