提交 3aafe5ae 编写于 作者: C Cody P Schafer 提交者: Arnaldo Carvalho de Melo

perf symbols: Use both runtime and debug images

We keep both a 'runtime' elf image as well as a 'debug' elf image around
and generate symbols by looking at both of these.

This eliminates the need for the want_symtab/goto restart mechanism
combined with iterating over and reopening the elf images a second time.

Also give dso__synthsize_plt_symbols() the runtime image (which has
dynsyms) instead of the symbol image (which may only have a symtab and
no dynsyms).

Previously if a debug image was found all runtime images were ignored.

This fixes 2 issues:

 - Symbol resolution to failure on PowerPC systems with debug symbols
   installed, as the debug images lack a '.opd' section which contains
   function descriptors.

 - On all archs, plt synthesis failed when a debug image was loaded and
   that debug image lacks a dynsym section while a runtime image has a
   dynsym section.

Assumptions:

 - If a .opd section exists, it is contained in the highest priority
   image with a dynsym section.

 - This generally implies that the debug image lacks a dynsym section
   (ie: it is marked as NO_BITS).
Signed-off-by: NCody 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/1344637382-22789-17-git-send-email-cody@linux.vnet.ibm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
上级 261360b6
......@@ -525,6 +525,11 @@ static int dso__swap_init(struct dso *dso, unsigned char eidata)
return 0;
}
bool symsrc__possibly_runtime(struct symsrc *ss)
{
return ss->dynsym || ss->opdsec;
}
bool symsrc__has_symtab(struct symsrc *ss)
{
return ss->symtab != NULL;
......
......@@ -260,6 +260,12 @@ int symsrc__init(struct symsrc *ss, struct dso *dso __used, const char *name,
return -1;
}
bool symsrc__possibly_runtime(struct symsrc *ss __used)
{
/* Assume all sym sources could be a runtime image. */
return true;
}
bool symsrc__has_symtab(struct symsrc *ss __used)
{
return false;
......
......@@ -1026,11 +1026,12 @@ int dso__load(struct dso *dso, struct map *map, symbol_filter_t filter)
{
char *name;
int ret = -1;
struct symsrc ss;
u_int i;
struct machine *machine;
char *root_dir = (char *) "";
int want_symtab;
int ss_pos = 0;
struct symsrc ss_[2];
struct symsrc *syms_ss = NULL, *runtime_ss = NULL;
dso__set_loaded(dso, map->type);
......@@ -1072,12 +1073,12 @@ int dso__load(struct dso *dso, struct map *map, symbol_filter_t filter)
root_dir = machine->root_dir;
/* 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
* Keep track of "interesting" ones (those which have a symtab, dynsym,
* and/or opd section) for processing.
*/
want_symtab = 1;
restart:
for (i = 0; i < DSO_BINARY_TYPE__SYMTAB_CNT; i++) {
struct symsrc *ss = &ss_[ss_pos];
bool next_slot = false;
enum dso_binary_type symtab_type = binary_type_symtab[i];
......@@ -1086,45 +1087,55 @@ int dso__load(struct dso *dso, struct map *map, symbol_filter_t filter)
continue;
/* Name is now the name of the next image to try */
if (symsrc__init(&ss, dso, name, symtab_type) < 0)
if (symsrc__init(ss, dso, name, symtab_type) < 0)
continue;
if (want_symtab && !symsrc__has_symtab(&ss)) {
symsrc__destroy(&ss);
continue;
if (!syms_ss && symsrc__has_symtab(ss)) {
syms_ss = ss;
next_slot = true;
}
ret = dso__load_sym(dso, map, &ss, &ss, filter, 0);
/*
* Some people seem to have debuginfo files _WITHOUT_ debug
* info!?!?
*/
if (!ret) {
symsrc__destroy(&ss);
continue;
if (!runtime_ss && symsrc__possibly_runtime(ss)) {
runtime_ss = ss;
next_slot = true;
}
if (ret > 0) {
int nr_plt;
if (next_slot) {
ss_pos++;
nr_plt = dso__synthesize_plt_symbols(dso, &ss, map, filter);
if (nr_plt > 0)
ret += nr_plt;
symsrc__destroy(&ss);
break;
if (syms_ss && runtime_ss)
break;
}
}
/*
* If we wanted a full symtab but no image had one,
* relax our requirements and repeat the search.
*/
if (ret <= 0 && want_symtab) {
want_symtab = 0;
goto restart;
if (!runtime_ss && !syms_ss)
goto out_free;
if (runtime_ss && !syms_ss) {
syms_ss = runtime_ss;
}
/* We'll have to hope for the best */
if (!runtime_ss && syms_ss)
runtime_ss = syms_ss;
if (syms_ss)
ret = dso__load_sym(dso, map, syms_ss, runtime_ss, filter, 0);
else
ret = -1;
if (ret > 0 && runtime_ss->dynsym) {
int nr_plt;
nr_plt = dso__synthesize_plt_symbols(dso, runtime_ss, map, filter);
if (nr_plt > 0)
ret += nr_plt;
}
for (; ss_pos > 0; ss_pos--)
symsrc__destroy(&ss_[ss_pos - 1]);
out_free:
free(name);
if (ret < 0 && strstr(dso->name, " (deleted)") != NULL)
return 0;
......
......@@ -253,6 +253,7 @@ void symsrc__destroy(struct symsrc *ss);
int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
enum dso_binary_type type);
bool symsrc__has_symtab(struct symsrc *ss);
bool symsrc__possibly_runtime(struct symsrc *ss);
#define DSO__SWAP(dso, type, val) \
({ \
......
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