perf symbols: Convert dso__load_syms to take 2 symsrc's

To properly handle platforms with an opd section, both a runtime image
(which contains the opd section but possibly lacks symbols) and a symbol
image (which probably lacks an opd section but has symbols).

The next patch ("perf symbol: use both runtime and debug images")
adjusts the callsite in dso__load() to take advantage of being able to
pass both runtime & debug images.

Assumptions made here:

 - The opd section, if it exists in the runtime image, has headers in
   both the runtime image and the debug/syms image.

 - The index of the opd section (again, only if it exists in the runtime
   image) is the same in both the runtime and debug/symbols image.

Both of these are true on RHEL, but it is unclear how accurate they are
in general (on platforms with function descriptors in opd sections).

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Hansen <dave@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matt Hellsley <matthltc@us.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1344637382-22789-16-git-send-email-cody@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 30 insertions, 27 deletions

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 492ebecfbfb6..36e4a458e7a1 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -619,7 +619,8 @@ out_close:
         return err;
 }
 
-int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *ss,
+int dso__load_sym(struct dso *dso, struct map *map,
+                  struct symsrc *syms_ss, struct symsrc *runtime_ss,
                   symbol_filter_t filter, int kmodule)
 {
         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
@@ -630,31 +631,27 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *ss,
         int err = -1;
         uint32_t idx;
         GElf_Ehdr ehdr;
-        GElf_Shdr shdr, opdshdr;
+        GElf_Shdr shdr;
         Elf_Data *syms, *opddata = NULL;
         GElf_Sym sym;
-        Elf_Scn *sec, *sec_strndx, *opdsec;
+        Elf_Scn *sec, *sec_strndx;
         Elf *elf;
         int nr = 0;
-        size_t opdidx = 0;
 
-        dso->symtab_type = ss->type;
+        dso->symtab_type = syms_ss->type;
 
-        if (!ss->symtab) {
-                ss->symtab  = ss->dynsym;
-                ss->symshdr = ss->dynshdr;
+        if (!syms_ss->symtab) {
+                syms_ss->symtab  = syms_ss->dynsym;
+                syms_ss->symshdr = syms_ss->dynshdr;
         }
 
-        elf = ss->elf;
-        ehdr = ss->ehdr;
-        sec = ss->symtab;
-        shdr = ss->symshdr;
+        elf = syms_ss->elf;
+        ehdr = syms_ss->ehdr;
+        sec = syms_ss->symtab;
+        shdr = syms_ss->symshdr;
 
-        opdsec = ss->opdsec;
-        opdshdr = ss->opdshdr;
-        opdidx  = ss->opdidx;
-        if (opdsec)
-                opddata = elf_rawdata(opdsec, NULL);
+        if (runtime_ss->opdsec)
+                opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 
         syms = elf_getdata(sec, NULL);
         if (syms == NULL)
@@ -679,13 +676,14 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *ss,
         nr_syms = shdr.sh_size / shdr.sh_entsize;
 
         memset(&sym, 0, sizeof(sym));
-        dso->adjust_symbols = ss->adjust_symbols;
+        dso->adjust_symbols = runtime_ss->adjust_symbols;
         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
                 struct symbol *f;
                 const char *elf_name = elf_sym__name(&sym, symstrs);
                 char *demangled = NULL;
                 int is_label = elf_sym__is_label(&sym);
                 const char *section_name;
+                bool used_opd = false;
 
                 if (kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
                     strcmp(elf_name, kmap->ref_reloc_sym->name) == 0)
@@ -704,14 +702,16 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *ss,
                                 continue;
                 }
 
-                if (opdsec && sym.st_shndx == opdidx) {
-                        u32 offset = sym.st_value - opdshdr.sh_addr;
+                if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
+                        u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
                         u64 *opd = opddata->d_buf + offset;
                         sym.st_value = DSO__SWAP(dso, u64, *opd);
-                        sym.st_shndx = elf_addr_to_index(elf, sym.st_value);
+                        sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
+                                        sym.st_value);
+                        used_opd = true;
                 }
 
-                sec = elf_getscn(elf, sym.st_shndx);
+                sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
                 if (!sec)
                         goto out_elf_end;
 
@@ -777,7 +777,8 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *ss,
                         goto new_symbol;
                 }
 
-                if (curr_dso->adjust_symbols && sym.st_value) {
+                if ((used_opd && runtime_ss->adjust_symbols)
+                                || (!used_opd && syms_ss->adjust_symbols)) {
                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
                                   (u64)sym.st_value, (u64)shdr.sh_addr,
diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c
index 11c2c606ce77..7747ea6d7e97 100644
--- a/tools/perf/util/symbol-minimal.c
+++ b/tools/perf/util/symbol-minimal.c
@@ -280,6 +280,7 @@ int dso__synthesize_plt_symbols(struct dso *dso __used,
 }
 
 int dso__load_sym(struct dso *dso, struct map *map __used, struct symsrc *ss,
+                  struct symsrc *runtime_ss __used,
                   symbol_filter_t filter __used, int kmodule __used)
 {
         unsigned char *build_id[BUILD_ID_SIZE];
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 8e7d74ff6ba5..739e5a32366a 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1094,7 +1094,7 @@ restart:
                         continue;
                 }
 
-                ret = dso__load_sym(dso, map, &ss, filter, 0);
+                ret = dso__load_sym(dso, map, &ss, &ss, filter, 0);
 
                 /*
                  * Some people seem to have debuginfo files _WITHOUT_ debug
@@ -1380,7 +1380,7 @@ int dso__load_vmlinux(struct dso *dso, struct map *map,
         if (symsrc__init(&ss, dso, symfs_vmlinux, symtab_type))
                 return -1;
 
-        err = dso__load_sym(dso, map, &ss, filter, 0);
+        err = dso__load_sym(dso, map, &ss, &ss, filter, 0);
         symsrc__destroy(&ss);
 
         if (err > 0) {
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index fa9f6b1cdc46..1f3eed21f35d 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -369,8 +369,9 @@ ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
                             struct machine *machine, u64 addr,
                             u8 *data, ssize_t size);
 int dso__test_data(void);
-int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *ss,
-                  symbol_filter_t filter, int kmodule);
+int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
+                  struct symsrc *runtime_ss, symbol_filter_t filter,
+                  int kmodule);
 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss,
                                 struct map *map, symbol_filter_t filter);