Re: [PATCH 2/9] perf/jit: enable jitdump support without dwarf

From: Arnaldo Carvalho de Melo
Date: Thu Oct 13 2016 - 14:17:35 EST


Em Thu, Oct 13, 2016 at 03:59:36AM -0700, Stephane Eranian escreveu:
> From: Maciej Debski <maciejd@xxxxxxxxxx>
>
> This patch modifies the build dependencies on the jitdump
> support in perf. As it stands jitdump was wrongfully made dependent
> 100% on using DWARF. However, the dwarf dependency, only exist if
> generating the source line table in genelf_debug.c. The rest of the
> support does not need DWARF.
>
> This patch removes the dependency on DWARF for the entire jitdump
> support. It keeps it only for the genelf_debug.c support.

Please add a:

Fixes: e12b202f8fb9 ("perf jitdump: Build only on supported archs")

Next time, so that scripts can pick patches for stable kernels, etc.

Adding it this time.

Thanks,

- Arnaldo


> Signed-off-by: Maciej Debski <maciejd@xxxxxxxxxx>
> Reviewed-by: Stephane Eranian <eranian@xxxxxxxxxx>
> ---
> tools/perf/Makefile.config | 2 --
> tools/perf/util/Build | 2 +-
> tools/perf/util/genelf.c | 9 +++++++--
> tools/perf/util/genelf.h | 2 ++
> 4 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 72edf83d76b7..8cfc310d4358 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -366,10 +366,8 @@ ifndef NO_SDT
> endif
>
> ifdef PERF_HAVE_JITDUMP
> - ifndef NO_DWARF
> $(call detected,CONFIG_JITDUMP)
> CFLAGS += -DHAVE_JITDUMP
> - endif
> endif
>
> ifeq ($(ARCH),powerpc)
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index eb60e613d795..1dc67efad634 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -120,7 +120,7 @@ libperf-y += demangle-rust.o
> ifdef CONFIG_JITDUMP
> libperf-$(CONFIG_LIBELF) += jitdump.o
> libperf-$(CONFIG_LIBELF) += genelf.o
> -libperf-$(CONFIG_LIBELF) += genelf_debug.o
> +libperf-$(CONFIG_DWARF) += genelf_debug.o
> endif
>
> CFLAGS_config.o += -DETC_PERFCONFIG="BUILD_STR($(ETC_PERFCONFIG_SQ))"
> diff --git a/tools/perf/util/genelf.c b/tools/perf/util/genelf.c
> index c1ef805c6a8f..14a73acc549c 100644
> --- a/tools/perf/util/genelf.c
> +++ b/tools/perf/util/genelf.c
> @@ -19,7 +19,9 @@
> #include <limits.h>
> #include <fcntl.h>
> #include <err.h>
> +#ifdef HAVE_DWARF_SUPPORT
> #include <dwarf.h>
> +#endif
>
> #include "perf.h"
> #include "genelf.h"
> @@ -157,7 +159,7 @@ gen_build_id(struct buildid_note *note, unsigned long load_addr, const void *cod
> int
> jit_write_elf(int fd, uint64_t load_addr, const char *sym,
> const void *code, int csize,
> - void *debug, int nr_debug_entries)
> + void *debug __maybe_unused, int nr_debug_entries __maybe_unused)
> {
> Elf *e;
> Elf_Data *d;
> @@ -386,11 +388,14 @@ jit_write_elf(int fd, uint64_t load_addr, const char *sym,
> shdr->sh_size = sizeof(bnote);
> shdr->sh_entsize = 0;
>
> +#ifdef HAVE_DWARF_SUPPORT
> if (debug && nr_debug_entries) {
> retval = jit_add_debug_info(e, load_addr, debug, nr_debug_entries);
> if (retval)
> goto error;
> - } else {
> + } else
> +#endif
> + {
> if (elf_update(e, ELF_C_WRITE) < 0) {
> warnx("elf_update 4 failed");
> goto error;
> diff --git a/tools/perf/util/genelf.h b/tools/perf/util/genelf.h
> index 2fbeb59c4bdd..5c933ac71451 100644
> --- a/tools/perf/util/genelf.h
> +++ b/tools/perf/util/genelf.h
> @@ -4,8 +4,10 @@
> /* genelf.c */
> int jit_write_elf(int fd, uint64_t code_addr, const char *sym,
> const void *code, int csize, void *debug, int nr_debug_entries);
> +#ifdef HAVE_DWARF_SUPPORT
> /* genelf_debug.c */
> int jit_add_debug_info(Elf *e, uint64_t code_addr, void *debug, int nr_debug_entries);
> +#endif
>
> #if defined(__arm__)
> #define GEN_ELF_ARCH EM_ARM
> --
> 1.9.1