From 6da80ce8c43ddda153208cbb46b75290cf566fac Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Fri, 30 Jul 2010 09:50:09 -0300 Subject: perf symbols: Improve debug image search when loading symbols Changes: * Simplification of the main search loop on dso__load() * Replace the search with a 2-pass search: * First, try to find an image with a proper symtab. * Second, repeat the search, accepting dynsym. A second scan should only ever happen when needed debug images are missing from the buildid cache or stale, i.e., when the cache is out of sync. Currently, the second scan also happens when using separated debug images, since the caching logic doesn't currently know how to cache those. Improvements to the cache behaviour ought to solve that. Signed-off-by: Dave Martin LKML-Reference: Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol.c | 96 ++++++++++++++++++++++++++++++------------------ 1 file changed, 61 insertions(+), 35 deletions(-) (limited to 'tools/perf/util') diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index e0d9480dc371..d99497ec52aa 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -966,7 +966,8 @@ static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr) } static int dso__load_sym(struct dso *self, struct map *map, const char *name, - int fd, symbol_filter_t filter, int kmodule) + int fd, symbol_filter_t filter, int kmodule, + int want_symtab) { struct kmap *kmap = self->kernel ? map__kmap(map) : NULL; struct map *curr_map = map; @@ -995,6 +996,7 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name, goto out_elf_end; } + /* Always reject images with a mismatched build-id: */ if (self->has_build_id) { u8 build_id[BUILD_ID_SIZE]; @@ -1008,6 +1010,9 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name, sec = elf_section_by_name(elf, &ehdr, &shdr, ".symtab", NULL); if (sec == NULL) { + if (want_symtab) + goto out_elf_end; + sec = elf_section_by_name(elf, &ehdr, &shdr, ".dynsym", NULL); if (sec == NULL) goto out_elf_end; @@ -1365,6 +1370,7 @@ int dso__load(struct dso *self, struct map *map, symbol_filter_t filter) int fd; struct machine *machine; const char *root_dir; + int want_symtab; dso__set_loaded(self, map->type); @@ -1391,13 +1397,18 @@ int dso__load(struct dso *self, struct map *map, symbol_filter_t filter) return ret; } - self->origin = DSO__ORIG_BUILD_ID_CACHE; - if (dso__build_id_filename(self, name, size) != NULL) - goto open_file; -more: - do { - self->origin++; + /* Iterate over candidate debug images. + * On the first pass, only load images if they have a full symtab. + * Failing that, do a second pass where we accept .dynsym also + */ + for (self->origin = DSO__ORIG_BUILD_ID_CACHE, want_symtab = 1; + self->origin != DSO__ORIG_NOT_FOUND; + self->origin++) { switch (self->origin) { + case DSO__ORIG_BUILD_ID_CACHE: + if (dso__build_id_filename(self, name, size) == NULL) + continue; + break; case DSO__ORIG_FEDORA: snprintf(name, size, "/usr/lib/debug%s.debug", self->long_name); @@ -1406,19 +1417,20 @@ more: snprintf(name, size, "/usr/lib/debug%s", self->long_name); break; - case DSO__ORIG_BUILDID: - if (self->has_build_id) { - char build_id_hex[BUILD_ID_SIZE * 2 + 1]; - build_id__sprintf(self->build_id, - sizeof(self->build_id), - build_id_hex); - snprintf(name, size, - "/usr/lib/debug/.build-id/%.2s/%s.debug", - build_id_hex, build_id_hex + 2); - break; + case DSO__ORIG_BUILDID: { + char build_id_hex[BUILD_ID_SIZE * 2 + 1]; + + if (!self->has_build_id) + continue; + + build_id__sprintf(self->build_id, + sizeof(self->build_id), + build_id_hex); + snprintf(name, size, + "/usr/lib/debug/.build-id/%.2s/%s.debug", + build_id_hex, build_id_hex + 2); } - self->origin++; - /* Fall thru */ + break; case DSO__ORIG_DSO: snprintf(name, size, "%s", self->long_name); break; @@ -1431,27 +1443,41 @@ more: break; default: - goto out; + /* + * If we wanted a full symtab but no image had one, + * relax our requirements and repeat the search. + */ + if (want_symtab) { + want_symtab = 0; + self->origin = DSO__ORIG_BUILD_ID_CACHE; + } else + continue; } -open_file: + + /* Name is now the name of the next image to try */ fd = open(name, O_RDONLY); - } while (fd < 0); + if (fd < 0) + continue; - ret = dso__load_sym(self, map, name, fd, filter, 0); - close(fd); + ret = dso__load_sym(self, map, name, fd, filter, 0, + want_symtab); + close(fd); - /* - * Some people seem to have debuginfo files _WITHOUT_ debug info!?!? - */ - if (!ret) - goto more; + /* + * Some people seem to have debuginfo files _WITHOUT_ debug + * info!?!? + */ + if (!ret) + continue; - if (ret > 0) { - int nr_plt = dso__synthesize_plt_symbols(self, map, filter); - if (nr_plt > 0) - ret += nr_plt; + if (ret > 0) { + int nr_plt = dso__synthesize_plt_symbols(self, map, filter); + if (nr_plt > 0) + ret += nr_plt; + break; + } } -out: + free(name); if (ret < 0 && strstr(self->name, " (deleted)") != NULL) return 0; @@ -1715,7 +1741,7 @@ static int dso__load_vmlinux(struct dso *self, struct map *map, return -1; dso__set_loaded(self, map->type); - err = dso__load_sym(self, map, vmlinux, fd, filter, 0); + err = dso__load_sym(self, map, vmlinux, fd, filter, 0, 0); close(fd); if (err > 0) -- cgit v1.2.3