1 files changed, 65 insertions, 51 deletions

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 8efe7e41109a..f40266b4845d 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;