Commit d2930ede authored by Remi Bernon's avatar Remi Bernon Committed by Arnaldo Carvalho de Melo
Browse files

perf symbol: Look for ImageBase in PE file to compute .text offset 



Instead of using the file offset in the debug file.

This fixes a regression from 00a34234 ("perf symbols: Make
dso__load_bfd_symbols() load PE files from debug cache only"), causing
incorrect symbol resolution when debug file have been stripped from
non-debug sections (in which case its .text section is empty and doesn't
have any file position).

The debug files could also be created with a different file alignment,
and have different file positions from the mmap-ed binary, or have the
section reordered.

This instead looks for the file image base, using the corresponding bfd
*ABS* symbols. As PE symbols only have 4 bytes, it also needs to keep
.text section vma high bits.

Signed-off-by: default avatarRemi Bernon <rbernon@codeweavers.com>
Fixes: 00a34234 ("perf symbols: Make dso__load_bfd_symbols() load PE files from debug cache only")
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Nicholas Fraser <nfraser@codeweavers.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210909192637.4139125-1-rbernon@codeweavers.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 51ae7fa6

tools/perf/util/symbol.c

+16 −4
Original line number Diff line number Diff line
@@ -1581,10 +1581,6 @@ int dso__load_bfd_symbols(struct dso *dso, const char *debugfile) 
	if (bfd_get_flavour(abfd) == bfd_target_elf_flavour)

		goto out_close;



	section = bfd_get_section_by_name(abfd, ".text");

	if (section)

		dso->text_offset = section->vma - section->filepos;



	symbols_size = bfd_get_symtab_upper_bound(abfd);

	if (symbols_size == 0) {

		bfd_close(abfd);
@@ -1602,6 +1598,22 @@ int dso__load_bfd_symbols(struct dso *dso, const char *debugfile) 
	if (symbols_count < 0)

		goto out_free;



	section = bfd_get_section_by_name(abfd, ".text");

	if (section) {

		for (i = 0; i < symbols_count; ++i) {

			if (!strcmp(bfd_asymbol_name(symbols[i]), "__ImageBase") ||

			    !strcmp(bfd_asymbol_name(symbols[i]), "__image_base__"))

				break;

		}

		if (i < symbols_count) {

			/* PE symbols can only have 4 bytes, so use .text high bits */

			dso->text_offset = section->vma - (u32)section->vma;

			dso->text_offset += (u32)bfd_asymbol_value(symbols[i]);

		} else {

			dso->text_offset = section->vma - section->filepos;

		}

	}



	qsort(symbols, symbols_count, sizeof(asymbol *), bfd_symbols__cmpvalue);



#ifdef bfd_get_section