[PATCH 31/52] tools/perf: Turn strlcpy() into a __weak function

From: Ingo Molnar
Date: Tue Oct 08 2013 - 06:19:04 EST


The strlcpy() feature check slows every build unnecessarily - so make it
a __weak function so it does not have to be auto-detected.

If the libc (or any other library) has an strlcpy() implementation it will
be used - otherwise our fallback is active.

Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-zjbrcupapu08ePsyYhhhxiwk@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
tools/perf/config/Makefile | 7 -------
tools/perf/config/feature-checks/Makefile | 4 ----
tools/perf/config/feature-checks/test-strlcpy.c | 8 --------
tools/perf/util/cache.h | 3 +--
tools/perf/util/include/linux/compiler.h | 4 ++++
tools/perf/util/path.c | 10 +++++++---
6 files changed, 12 insertions(+), 24 deletions(-)

diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index 57ec8b6..cc857fb 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -121,7 +121,6 @@ FEATURE_TESTS = \
libperl \
libpython \
libpython-version \
- strlcpy \
libbfd \
on-exit \
backtrace \
@@ -426,12 +425,6 @@ else
endif
endif

-ifndef NO_STRLCPY
- ifeq ($(feature-strlcpy), 1)
- CFLAGS += -DHAVE_STRLCPY_SUPPORT
- endif
-endif
-
ifndef NO_ON_EXIT
ifeq ($(feature-on-exit), 1)
CFLAGS += -DHAVE_ON_EXIT_SUPPORT
diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile
index 0e4dbc2..c65bdac 100644
--- a/tools/perf/config/feature-checks/Makefile
+++ b/tools/perf/config/feature-checks/Makefile
@@ -19,7 +19,6 @@ FILES= \
test-libperl \
test-libpython \
test-libpython-version \
- test-strlcpy \
test-libbfd \
test-on-exit \
test-backtrace \
@@ -116,9 +115,6 @@ test-libpython:
test-libpython-version:
$(BUILD) $(FLAGS_PYTHON_EMBED)

-test-strlcpy:
- $(BUILD)
-
test-libbfd:
$(BUILD) -DPACKAGE='perf' -DPACKAGE=perf -lbfd -ldl

diff --git a/tools/perf/config/feature-checks/test-strlcpy.c b/tools/perf/config/feature-checks/test-strlcpy.c
deleted file mode 100644
index 4a6b6ff..0000000
--- a/tools/perf/config/feature-checks/test-strlcpy.c
+++ /dev/null
@@ -1,8 +0,0 @@
-#include <stdlib.h>
-extern size_t strlcpy(char *dest, const char *src, size_t size);
-
-int main(void)
-{
- strlcpy(NULL, NULL, 0);
- return 0;
-}
diff --git a/tools/perf/util/cache.h b/tools/perf/util/cache.h
index 442953c..7b176dd 100644
--- a/tools/perf/util/cache.h
+++ b/tools/perf/util/cache.h
@@ -70,8 +70,7 @@ extern char *perf_path(const char *fmt, ...) __attribute__((format (printf, 1, 2
extern char *perf_pathdup(const char *fmt, ...)
__attribute__((format (printf, 1, 2)));

-#ifndef HAVE_STRLCPY_SUPPORT
+/* Matches the libc/libbsd function attribute so we declare this unconditionally: */
extern size_t strlcpy(char *dest, const char *src, size_t size);
-#endif

#endif /* __PERF_CACHE_H */
diff --git a/tools/perf/util/include/linux/compiler.h b/tools/perf/util/include/linux/compiler.h
index bef4d3d..b003ad7 100644
--- a/tools/perf/util/include/linux/compiler.h
+++ b/tools/perf/util/include/linux/compiler.h
@@ -23,4 +23,8 @@
# define __force
#endif

+#ifndef __weak
+# define __weak __attribute__((weak))
+#endif
+
#endif
diff --git a/tools/perf/util/path.c b/tools/perf/util/path.c
index f395874..5d13cb4 100644
--- a/tools/perf/util/path.c
+++ b/tools/perf/util/path.c
@@ -22,19 +22,23 @@ static const char *get_perf_dir(void)
return ".";
}

-#ifndef HAVE_STRLCPY_SUPPORT
-size_t strlcpy(char *dest, const char *src, size_t size)
+/*
+ * If libc has strlcpy() then that version will override this
+ * implementation:
+ */
+size_t __weak strlcpy(char *dest, const char *src, size_t size)
{
size_t ret = strlen(src);

if (size) {
size_t len = (ret >= size) ? size - 1 : ret;
+
memcpy(dest, src, len);
dest[len] = '\0';
}
+
return ret;
}
-#endif

static char *get_pathname(void)
{
--
1.8.3.1

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