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 00a3423492bc90be ("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: Remi Bernon <rbernon@codeweavers.com>
Fixes: 00a3423492bc90be ("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: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 77fc46c..0fc9a54 100644 (file)
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -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;
 
        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);
        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;
 
        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
        qsort(symbols, symbols_count, sizeof(asymbol *), bfd_symbols__cmpvalue);
 
 #ifdef bfd_get_section