kernel/linux.git/tools/include/linux/compiler-gcc.h, branch v6.19.11

Improve consistency of '#error' directive messages

2024-11-12T01:17:04+00:00

Remove the use of contractions and use proper punctuation in #error directive messages that discourage the direct inclusion of header files. Link: https://lkml.kernel.org/r/20241105032231.28833-1-natanielfarzan@gmail.com Signed-off-by: Nataniel Farzan Signed-off-by: Andrew Morton

tools: Rename __fallthrough to fallthrough

2023-04-07T00:41:00+00:00

Rename the fallthrough attribute to better align with the kernel version. Copy the definition from include/linux/compiler_attributes.h including the #else clause. Adding the #else clause allows the tools compiler.h header to drop the check for a definition entirely and keeps both definitions together. Change any __fallthrough statements to fallthrough anywhere it was used within perf. This allows other tools to use the same key word as the kernel. Committer notes: Did some missing conversions to: builtin-list.c Also included gtk.h before the 'fallthrough' definition in: tools/perf/ui/gtk/hists.c tools/perf/ui/gtk/helpline.c tools/perf/ui/gtk/browser.c As it is the arg name for a macro in glib.h: /var/home/acme/git/perf-tools-next/tools/include/linux/compiler-gcc.h:16:55: error: missing binary operator before token "(" 16 | # define fallthrough __attribute__((__fallthrough__)) | ^ /usr/include/glib-2.0/glib/gmacros.h:637:28: note: in expansion of macro ‘fallthrough’ 637 | #if g_macro__has_attribute(fallthrough) Reviewed-by: Miguel Ojeda Signed-off-by: Liam Howlett Cc: Ingo Molnar Cc: Mark Rutland Cc: Miguel Ojeda Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Rasmus Villemoes Cc: Tom Rix Cc: linux-sparse@vger.kernel.org Cc: llvm@lists.linux.dev Link: https://lore.kernel.org/r/20221125154947.2163498-1-Liam.Howlett@oracle.com Signed-off-by: Arnaldo Carvalho de Melo

tools: compiler-gcc.h: Guard error attribute use with __has_attribute

2021-09-13T22:51:41+00:00

When building objtool with HOSTCC=clang, there are several errors along the lines of orc_dump.c:201:28: error: unknown attribute 'error' ignored [-Werror,-Wunknown-attributes] This occurs after commit 4e59869aa655 ("compiler-gcc.h: drop checks for older GCC versions"), which removed the GCC_VERSION gating. The removed version check just so happened to prevent __compiletime_error() from being defined with clang because it pretends to be GCC 4.2.1 for compatibility but the error attribute was not added to clang until 14.0.0. Commit 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") and commit a3f8a30f3f00 ("Compiler Attributes: use feature checks instead of version checks") refactored the handling of attributes in the main kernel to avoid situations like this but that refactoring has never been done for the tools directory. Refactoring is a rather large undertaking and this has never been an issue before so instead, just guard the definition of __compiletime_error() with __has_attribute() so that there are no more errors. Fixes: 4e59869aa655 ("compiler-gcc.h: drop checks for older GCC versions") Signed-off-by: Nathan Chancellor Signed-off-by: Linus Torvalds

compiler-gcc.h: drop checks for older GCC versions

2021-09-13T17:18:29+00:00

Now that GCC 5.1 is the minimally supported default, drop the values we don't use. Signed-off-by: Nick Desaulniers Reviewed-by: Kees Cook Reviewed-by: Nathan Chancellor Signed-off-by: Linus Torvalds

compiler.h: drop fallback overflow checkers

2021-09-13T17:18:28+00:00

Once upgrading the minimum supported version of GCC to 5.1, we can drop the fallback code for !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW. This is effectively a revert of commit f0907827a8a9 ("compiler.h: enable builtin overflow checkers and add fallback code") Link: https://github.com/ClangBuiltLinux/linux/issues/1438#issuecomment-916745801 Suggested-by: Rasmus Villemoes Signed-off-by: Nick Desaulniers Acked-by: Kees Cook Reviewed-by: Nathan Chancellor Signed-off-by: Linus Torvalds

perf tools: Remove broken __no_tail_call attribute

2020-11-03T11:32:15+00:00

The GCC specific __attribute__((optimize)) attribute does not what is commonly expected and is explicitly recommended against using in production code by the GCC people. Unlike what is often expected, it doesn't add to the optimization flags, but it fully replaces them, loosing any and all optimization flags provided by the compiler commandline. The only guaranteed upon means of inhibiting tail-calls is by placing a volatile asm with side-effects after the call such that the tail-call simply cannot be done. Given the original commit wasn't specific on which calls were the problem, this removal might re-introduce the problem, which can then be re-analyzed and cured properly. Signed-off-by: Peter Zijlstra Acked-by: Ard Biesheuvel Acked-by: Miguel Ojeda Cc: Alexei Starovoitov Cc: Arnd Bergmann Cc: Arvind Sankar Cc: Daniel Borkmann Cc: Geert Uytterhoeven Cc: Ian Rogers Cc: Josh Poimboeuf Cc: Kees Kook Cc: Martin Liška Cc: Nick Desaulniers Cc: Randy Dunlap Cc: Thomas Gleixner Link: http://lore.kernel.org/lkml/20201028081123.GT2628@hirez.programming.kicks-ass.net Signed-off-by: Arnaldo Carvalho de Melo

tools compiler.h: Add attribute to disable tail calls

2020-06-01T15:24:21+00:00

Tail call optimizations can remove stack frames that are used in unwinding tests. Add an attribute that can be used to disable the tail call optimization. Tested on clang and GCC. Committer notes: Old versions of clang don't like that __attribute__((optimize)), so add an ifdef to make it go away. Signed-off-by: Ian Rogers Cc: Alexander Shishkin Cc: Alexei Starovoitov Cc: clang-built-linux@googlegroups.com Cc: Jakub Kicinski Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Quentin Monnet Cc: Stephane Eranian Link: http://lore.kernel.org/lkml/20200530082015.39162-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

tools: bpftool: move "__printf()" attributes to header file

2019-08-16T05:06:46+00:00

Some functions in bpftool have a "__printf()" format attributes to tell the compiler they should expect printf()-like arguments. But because these attributes are not used for the function prototypes in the header files, the compiler does not run the checks everywhere the functions are used, and some mistakes on format string and corresponding arguments slipped in over time. Let's move the __printf() attributes to the correct places. Note: We add guards around the definition of GCC_VERSION in tools/include/linux/compiler-gcc.h to prevent a conflict in jit_disasm.c on GCC_VERSION from headers pulled via libbfd. Fixes: c101189bc968 ("tools: bpftool: fix -Wmissing declaration warnings") Reported-by: Jakub Kicinski Signed-off-by: Quentin Monnet Reviewed-by: Jakub Kicinski Signed-off-by: Alexei Starovoitov

tools: bpf: make use of reallocarray

2018-07-11T20:13:34+00:00

reallocarray() is a safer variant of realloc which checks for multiplication overflow in case of array allocation. Since it's not available in Glibc < 2.26 import kernel's overflow.h and add a static inline implementation when needed. Use feature detection to probe for existence of reallocarray. Signed-off-by: Jakub Kicinski Reviewed-by: Quentin Monnet Reviewed-by: Jiong Wang Signed-off-by: Daniel Borkmann

tools include compiler-gcc: Add __pure attribute helper

2018-05-17T18:17:21+00:00

Adopt it from the kernel sources, will be used soon. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-oubheiqj8edo5rzewt11cbn0@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo