Disable a couple of compilation warning (which are treated as errors) on
strlcpy definition and declaration, allow users to compile perf and
kernel (objtool).
1. When glibc have strlcpy (such as in ALT Linux since 2004) objtool and
perf build fails with this (in gcc):
In file included from exec-cmd.c:3:
tools/include/linux/string.h:20:15: error: redundant redeclaration of ‘strlcpy’ [-Werror=redundant-decls]
20 | extern size_t strlcpy(char *dest, const char *src, size_t size);
2. Clang ignores `-Wredundant-decls', but produces another warning when
building perf:
CC util/string.o
../lib/string.c:99:8: error: attribute declaration must precede definition [-Werror,-Wignored-attributes]
size_t __weak strlcpy(char *dest, const char *src, size_t size)
../../tools/include/linux/compiler.h:66:34: note: expanded from macro '__weak'
# define __weak __attribute__((weak))
/usr/include/bits/string_fortified.h:151:8: note: previous definition is here
__NTH (strlcpy (char *__restrict __dest, const char *__restrict __src,
Fixes: ce99091 ("perf tools: Move strlcpy() from perf to tools/lib/string.c")
Fixes: 0215d59 ("tools lib: Reinstate strlcpy() header guard with __UCLIBC__")
Resolves: https://bugzilla.kernel.org/show_bug.cgi?id=118481
Signed-off-by: Vitaly Chikunov <[email protected]>
Reviewed-by: Dmitry V. Levin <[email protected]>
Cc: Dmitry V. Levin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: [email protected]
---
Changes since v2:
- v2 was failing to compile on gcc-4.9, because there was no `-Wignored-attributes'.
Make this pragma only efficient for Clang.
Reported-by: kbuild test robot <[email protected]>
Changes since v1:
- Fix compiling with clang due to __weak triggering `-Wignored-attributes'.
tools/include/linux/string.h | 3 +++
tools/lib/string.c | 7 +++++++
2 files changed, 10 insertions(+)
diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index 980cb9266718..99ede7f5dfb8 100644
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -17,7 +17,10 @@ int strtobool(const char *s, bool *res);
* However uClibc headers also define __GLIBC__ hence the hack below
*/
#if defined(__GLIBC__) && !defined(__UCLIBC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wredundant-decls"
extern size_t strlcpy(char *dest, const char *src, size_t size);
+#pragma GCC diagnostic pop
#endif
char *str_error_r(int errnum, char *buf, size_t buflen);
diff --git a/tools/lib/string.c b/tools/lib/string.c
index f2ae1b87c719..f645343815de 100644
--- a/tools/lib/string.c
+++ b/tools/lib/string.c
@@ -96,6 +96,10 @@ int strtobool(const char *s, bool *res)
* If libc has strlcpy() then that version will override this
* implementation:
*/
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wignored-attributes"
+#endif
size_t __weak strlcpy(char *dest, const char *src, size_t size)
{
size_t ret = strlen(src);
@@ -107,6 +111,9 @@ size_t __weak strlcpy(char *dest, const char *src, size_t size)
}
return ret;
}
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
/**
* skip_spaces - Removes leading whitespace from @str.
--
2.11.0
The following commit has been merged into the perf/core branch of tip:
Commit-ID: 6c4798d3f08b81c2c52936b10e0fa872590c96ae
Gitweb: https://git.kernel.org/tip/6c4798d3f08b81c2c52936b10e0fa872590c96ae
Author: Vitaly Chikunov <[email protected]>
AuthorDate: Tue, 24 Dec 2019 20:20:29 +03:00
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitterDate: Mon, 06 Jan 2020 11:46:10 -03:00
tools lib: Fix builds when glibc contains strlcpy()
Disable a couple of compilation warnings (which are treated as errors)
on strlcpy() definition and declaration, allowing users to compile perf
and kernel (objtool) when:
1. glibc have strlcpy() (such as in ALT Linux since 2004) objtool and
perf build fails with this (in gcc):
In file included from exec-cmd.c:3:
tools/include/linux/string.h:20:15: error: redundant redeclaration of ‘strlcpy’ [-Werror=redundant-decls]
20 | extern size_t strlcpy(char *dest, const char *src, size_t size);
2. clang ignores `-Wredundant-decls', but produces another warning when
building perf:
CC util/string.o
../lib/string.c:99:8: error: attribute declaration must precede definition [-Werror,-Wignored-attributes]
size_t __weak strlcpy(char *dest, const char *src, size_t size)
../../tools/include/linux/compiler.h:66:34: note: expanded from macro '__weak'
# define __weak __attribute__((weak))
/usr/include/bits/string_fortified.h:151:8: note: previous definition is here
__NTH (strlcpy (char *__restrict __dest, const char *__restrict __src,
Committer notes:
The
#pragma GCC diagnostic
directive was introduced in gcc 4.6, so check for that as well.
Fixes: ce99091 ("perf tools: Move strlcpy() from perf to tools/lib/string.c")
Fixes: 0215d59 ("tools lib: Reinstate strlcpy() header guard with __UCLIBC__")
Resolves: https://bugzilla.kernel.org/show_bug.cgi?id=118481
Signed-off-by: Vitaly Chikunov <[email protected]>
Reviewed-by: Dmitry Levin <[email protected]>
Cc: Dmitry Levin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: kbuild test robot <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
Cc: Vineet Gupta <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/include/linux/string.h | 8 ++++++++
tools/lib/string.c | 7 +++++++
2 files changed, 15 insertions(+)
diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index 980cb92..5e9e781 100644
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -17,7 +17,15 @@ int strtobool(const char *s, bool *res);
* However uClibc headers also define __GLIBC__ hence the hack below
*/
#if defined(__GLIBC__) && !defined(__UCLIBC__)
+// pragma diagnostic was introduced in gcc 4.6
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wredundant-decls"
+#endif
extern size_t strlcpy(char *dest, const char *src, size_t size);
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+#pragma GCC diagnostic pop
+#endif
#endif
char *str_error_r(int errnum, char *buf, size_t buflen);
diff --git a/tools/lib/string.c b/tools/lib/string.c
index f2ae1b8..f645343 100644
--- a/tools/lib/string.c
+++ b/tools/lib/string.c
@@ -96,6 +96,10 @@ int strtobool(const char *s, bool *res)
* If libc has strlcpy() then that version will override this
* implementation:
*/
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wignored-attributes"
+#endif
size_t __weak strlcpy(char *dest, const char *src, size_t size)
{
size_t ret = strlen(src);
@@ -107,6 +111,9 @@ size_t __weak strlcpy(char *dest, const char *src, size_t size)
}
return ret;
}
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
/**
* skip_spaces - Removes leading whitespace from @str.