diff options
| -rw-r--r-- | tools/perf/util/symbol.c | 116 |
1 files changed, 65 insertions, 51 deletions
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 8efe7e41109..f40266b4845 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -374,36 +374,61 @@ static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, idx < nr_entries; \ ++idx, pos = gelf_getrela(reldata, idx, &pos_mem)) -static int dso__synthesize_plt_symbols(struct dso *self, Elf *elf, - GElf_Ehdr *ehdr, Elf_Scn *scn_dynsym, - GElf_Shdr *shdr_dynsym, - size_t dynsym_idx, int verbose) +/* + * We need to check if we have a .dynsym, so that we can handle the + * .plt, synthesizing its symbols, that aren't on the symtabs (be it + * .dynsym or .symtab). + * And always look at the original dso, not at debuginfo packages, that + * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS). + */ +static int dso__synthesize_plt_symbols(struct dso *self, int verbose) { uint32_t nr_rel_entries, idx; GElf_Sym sym; u64 plt_offset; GElf_Shdr shdr_plt; struct symbol *f; - GElf_Shdr shdr_rel_plt; + GElf_Shdr shdr_rel_plt, shdr_dynsym; Elf_Data *reldata, *syms, *symstrs; - Elf_Scn *scn_plt_rel, *scn_symstrs; + Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym; + size_t dynsym_idx; + GElf_Ehdr ehdr; char sympltname[1024]; - int nr = 0, symidx; + Elf *elf; + int nr = 0, symidx, fd, err = 0; + + fd = open(self->name, O_RDONLY); + if (fd < 0) + goto out; + + elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + if (elf == NULL) + goto out_close; + + if (gelf_getehdr(elf, &ehdr) == NULL) + goto out_elf_end; + + scn_dynsym = elf_section_by_name(elf, &ehdr, &shdr_dynsym, + ".dynsym", &dynsym_idx); + if (scn_dynsym == NULL) + goto out_elf_end; - scn_plt_rel = elf_section_by_name(elf, ehdr, &shdr_rel_plt, + scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, ".rela.plt", NULL); if (scn_plt_rel == NULL) { - scn_plt_rel = elf_section_by_name(elf, ehdr, &shdr_rel_plt, + scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, ".rel.plt", NULL); if (scn_plt_rel == NULL) - return 0; + goto out_elf_end; } + err = -1; + if (shdr_rel_plt.sh_link != dynsym_idx) - return 0; + goto out_elf_end; - if (elf_section_by_name(elf, ehdr, &shdr_plt, ".plt", NULL) == NULL) - return 0; + if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL) + goto out_elf_end; /* * Fetch the relocation section to find the indexes to the GOT @@ -411,19 +436,19 @@ static int dso__synthesize_plt_symbols(struct dso *self, Elf *elf, */ reldata = elf_getdata(scn_plt_rel, NULL); if (reldata == NULL) - return -1; + goto out_elf_end; syms = elf_getdata(scn_dynsym, NULL); if (syms == NULL) - return -1; + goto out_elf_end; - scn_symstrs = elf_getscn(elf, shdr_dynsym->sh_link); + scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link); if (scn_symstrs == NULL) - return -1; + goto out_elf_end; symstrs = elf_getdata(scn_symstrs, NULL); if (symstrs == NULL) - return -1; + goto out_elf_end; nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize; plt_offset = shdr_plt.sh_offset; @@ -442,7 +467,7 @@ static int dso__synthesize_plt_symbols(struct dso *self, Elf *elf, f = symbol__new(plt_offset, shdr_plt.sh_entsize, sympltname, self->sym_priv_size, 0, verbose); if (!f) - return -1; + goto out_elf_end; dso__insert_symbol(self, f); ++nr; @@ -460,19 +485,25 @@ static int dso__synthesize_plt_symbols(struct dso *self, Elf *elf, f = symbol__new(plt_offset, shdr_plt.sh_entsize, sympltname, self->sym_priv_size, 0, verbose); if (!f) - return -1; + goto out_elf_end; dso__insert_symbol(self, f); ++nr; } - } else { - /* - * TODO: There are still one more shdr_rel_plt.sh_type - * I have to investigate, but probably should be ignored. - */ } - return nr; + err = 0; +out_elf_end: + elf_end(elf); +out_close: + close(fd); + + if (err == 0) + return nr; +out: + fprintf(stderr, "%s: problems reading %s PLT info.\n", + __func__, self->name); + return 0; } static int dso__load_sym(struct dso *self, int fd, const char *name, @@ -486,9 +517,8 @@ static int dso__load_sym(struct dso *self, int fd, const char *name, GElf_Shdr shdr; Elf_Data *syms; GElf_Sym sym; - Elf_Scn *sec, *sec_dynsym, *sec_strndx; + Elf_Scn *sec, *sec_strndx; Elf *elf; - size_t dynsym_idx; int nr = 0; elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); @@ -505,32 +535,11 @@ static int dso__load_sym(struct dso *self, int fd, const char *name, goto out_elf_end; } - /* - * We need to check if we have a .dynsym, so that we can handle the - * .plt, synthesizing its symbols, that aren't on the symtabs (be it - * .dynsym or .symtab) - */ - sec_dynsym = elf_section_by_name(elf, &ehdr, &shdr, - ".dynsym", &dynsym_idx); - if (sec_dynsym != NULL) { - nr = dso__synthesize_plt_symbols(self, elf, &ehdr, - sec_dynsym, &shdr, - dynsym_idx, verbose); - if (nr < 0) - goto out_elf_end; - } - - /* - * But if we have a full .symtab (that is a superset of .dynsym) we - * should add the symbols not in the .dynsyn - */ sec = elf_section_by_name(elf, &ehdr, &shdr, ".symtab", NULL); if (sec == NULL) { - if (sec_dynsym == NULL) + sec = elf_section_by_name(elf, &ehdr, &shdr, ".dynsym", NULL); + if (sec == NULL) goto out_elf_end; - - sec = sec_dynsym; - gelf_getshdr(sec, &shdr); } syms = elf_getdata(sec, NULL); @@ -669,6 +678,11 @@ more: if (!ret) goto more; + if (ret > 0) { + int nr_plt = dso__synthesize_plt_symbols(self, verbose); + if (nr_plt > 0) + ret += nr_plt; + } out: free(name); return ret; |