Messages in this thread Patch in this message | | | Subject | Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect | From | Marti Raudsepp <> | Date | Sat, 24 Oct 2009 18:13:12 +0300 |
| |
On Sat, 2009-10-24 at 11:26 -0200, Lucas De Marchi wrote: > In this case you should define PERF_ELF_C_READ_MMAP as ELF_C_READ_MMAP > when using elftutils: > #ifndef ELF_C_READ_MMAP > # define PERF_ELF_C_READ_MMAP ELF_C_READ > #else > # define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP > #endif
That's what I wanted to do at first, but it doesn't work because ELF_C_READ_MMAP is an enum constant -- not a #define
But defining our own PERF_ELF_C_READ_MMAP is a good idea and much cleaner than the earlier mess. Thanks
> I think the comment is wrong. I downloaded the latest version of > libelf, i.e. 0.8.12 at http://www.mr511.de/software/english.html, and > there's no support to ELF_C_READ_MMAP. It's a elfutils' feature only.
I guess the comment was confusing. With "libelf 0.8" I meant the whole 0.8.x series.
Marti
--
perf tools: add compatibility with libelf 0.8.x and autodetect
The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8.x is detected. libelf 0.8.x is still maintained and some distributions such as Arch Linux use it instead of elfutils.
Can't use #ifdef ELF_C_READ_MMAP because it's an enum constant not a define.
Signed-off-by: Marti Raudsepp <marti@juffo.org> --- Makefile | 6 +++++- util/symbol.c | 6 +++--- util/symbol.h | 10 ++++++++++ 3 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/tools/perf/Makefile b/tools/perf/Makefile --- a/tools/perf/Makefile +++ b/tools/perf/Makefile @@ -422,7 +422,11 @@ PTHREAD_LIBS = endif -ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y) +ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y) + ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y) + BASIC_CFLAGS += -DLIBELF_NO_MMAP + endif +else msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]); endif diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -413,7 +413,7 @@ if (fd < 0) goto out; - elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) goto out_close; @@ -533,7 +533,7 @@ Elf *elf; int nr = 0, kernel = !strcmp("[kernel]", self->name); - elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) { if (v) fprintf(stderr, "%s: cannot read %s ELF file.\n", @@ -675,7 +675,7 @@ if (fd < 0) goto out; - elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) { if (v) fprintf(stderr, "%s: cannot read %s ELF file.\n", diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h --- a/tools/perf/util/symbol.h +++ b/tools/perf/util/symbol.h @@ -27,6 +27,16 @@ #endif #endif +/* + * libelf 0.8.x and earlier do not support elf_c_read_mmap; for newer versions + * we can use mmap to reduce memory usage + */ +#ifdef LIBELF_NO_MMAP +# define PERF_ELF_C_READ_MMAP ELF_C_READ +#else +# define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP +#endif + #ifndef DMGL_PARAMS #define DMGL_PARAMS (1 << 0) /* Include function args */ #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
| |