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-rw-r--r--tools/perf/util/symbol.c116
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;
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-27 11:55:09 +0000