Commit 3aafe5ae authored by Cody P Schafer's avatar Cody P Schafer Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarCody 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.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 261360b6

tools/perf/util/symbol-elf.c

+5 −0
Original line number Diff line number Diff line
@@ -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;

tools/perf/util/symbol-minimal.c

+6 −0
Original line number Diff line number Diff line
@@ -260,6 +260,12 @@ out_close: 
	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;

tools/perf/util/symbol.c

+44 −33
Original line number Diff line number Diff line
@@ -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 @@ restart: 
			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);

			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;

tools/perf/util/symbol.h

+1 −0
Original line number Diff line number Diff line
@@ -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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