From 57115bb054f20a7e64182c8ffdbef976a914f074 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Tue, 8 Oct 2013 19:56:13 +0000 Subject: fix PR symtab/15597 This patch fixes gdb PR symtab/15597. The bug is that the .gnu_debugaltlink section includes the build-id of the alt file, but gdb does not use it. This patch fixes the problem by changing gdb to do what it ought to always have done: verify the build id of the file found using the filename in .gnu_debugaltlink; and if that does not match, try to find the correct debug file using the build-id and debug-file-directory. This patch touches BFD. Previously, gdb had its own code for parsing .gnu_debugaltlink; I changed it to use the BFD functions after those were introduced. However, the BFD functions are incorrect -- they assume that .gnu_debugaltlink is formatted like .gnu_debuglink. However, it it is not. Instead, it consists of a file name followed by the build-id -- no alignment, and the build-id is not a CRC. Fixing this properly is a bit of a pain. But, because separate_alt_debug_file_exists just has a FIXME for the build-id case, I did not fix it properly. Instead I introduced a hack. This leaves BFD working just as well as it did before my patch. I'm willing to do something better here but I could use some guidance as to what. It seems that the build-id code in BFD is largely punted on. FWIW gdb is the only user of bfd_get_alt_debug_link_info outside of BFD itself. I moved the build-id logic out of elfread.c and into a new file. This seemed cleanest to me. Writing a test case was a bit of a pain. I added a couple new features to the DWARF assembler to handle this. Built and regtested on x86-64 Fedora 18. * bfd-in2.h: Rebuild. * opncls.c (bfd_get_alt_debug_link_info): Add buildid_len parameter. Change type of buildid_out. Update. (get_alt_debug_link_info_shim): New function. (bfd_follow_gnu_debuglink): Use it. * Makefile.in (SFILES): Add build-id.c. (HFILES_NO_SRCDIR): Add build-id.h. * build-id.c: New file, largely from elfread.c. Modified most functions. * build-id.h: New file. * dwarf2read.c (dwarf2_get_dwz_file): Update for change to bfd_get_alt_debug_link_info. Verify dwz file's build-id. Search for dwz file using build-id. * elfread.c (build_id_bfd_get, build_id_verify) (build_id_to_debug_filename, find_separate_debug_file): Remove. * gdb.dwarf2/dwzbuildid.exp: New file. * lib/dwarf.exp (Dwarf::_section): Add "flags" and "type" parameters. (Dwarf::_defer_output): Change "section" parameter to "section_spec"; update. (Dwarf::gnu_debugaltlink, Dwarf::_note, Dwarf::build_id): New procs. --- bfd/ChangeLog | 8 ++++++++ bfd/bfd-in2.h | 3 ++- bfd/opncls.c | 41 ++++++++++++++++++++++++++++++++--------- 3 files changed, 42 insertions(+), 10 deletions(-) (limited to 'bfd') diff --git a/bfd/ChangeLog b/bfd/ChangeLog index c5d98271d19..e8534ddaee9 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,11 @@ +2013-10-08 Tom Tromey + + * bfd-in2.h: Rebuild. + * opncls.c (bfd_get_alt_debug_link_info): Add buildid_len + parameter. Change type of buildid_out. Update. + (get_alt_debug_link_info_shim): New function. + (bfd_follow_gnu_debuglink): Use it. + 2013-10-08 Andreas Schwab * elf32-m68k.c (elf_m68k_size_dynamic_sections): Add DT_DEBUG also diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h index 41f7a682c3d..67eb7da2e34 100644 --- a/bfd/bfd-in2.h +++ b/bfd/bfd-in2.h @@ -1067,7 +1067,8 @@ unsigned long bfd_calc_gnu_debuglink_crc32 char *bfd_get_debug_link_info (bfd *abfd, unsigned long *crc32_out); -char *bfd_get_alt_debug_link_info (bfd *abfd, unsigned long *crc32_out); +char *bfd_get_alt_debug_link_info (bfd * abfd, size_t *buildid_len, + bfd_byte **buildid_out); char *bfd_follow_gnu_debuglink (bfd *abfd, const char *dir); diff --git a/bfd/opncls.c b/bfd/opncls.c index cd9c826dd4b..f29b2c8a371 100644 --- a/bfd/opncls.c +++ b/bfd/opncls.c @@ -1194,18 +1194,21 @@ FUNCTION bfd_get_alt_debug_link_info SYNOPSIS - char *bfd_get_alt_debug_link_info (bfd *abfd, unsigned long *crc32_out); + char *bfd_get_alt_debug_link_info (bfd * abfd, size_t *buildid_len, + bfd_byte **buildid_out); DESCRIPTION Fetch the filename and BuildID value for any alternate debuginfo associated with @var{abfd}. Return NULL if no such info found, - otherwise return filename and update @var{buildid_out}. The - returned filename is allocated with @code{malloc}; freeing it - is the responsibility of the caller. + otherwise return filename and update @var{buildid_len} and + @var{buildid_out}. The returned filename and build_id are + allocated with @code{malloc}; freeing them is the + responsibility of the caller. */ char * -bfd_get_alt_debug_link_info (bfd * abfd, unsigned long * buildid_out) +bfd_get_alt_debug_link_info (bfd * abfd, size_t *buildid_len, + bfd_byte **buildid_out) { asection *sect; bfd_byte *contents; @@ -1213,6 +1216,7 @@ bfd_get_alt_debug_link_info (bfd * abfd, unsigned long * buildid_out) char *name; BFD_ASSERT (abfd); + BFD_ASSERT (buildid_len); BFD_ASSERT (buildid_out); sect = bfd_get_section_by_name (abfd, GNU_DEBUGALTLINK); @@ -1227,12 +1231,13 @@ bfd_get_alt_debug_link_info (bfd * abfd, unsigned long * buildid_out) return NULL; } - /* BuildID value is stored after the filename, aligned up to 4 bytes. */ + /* BuildID value is stored after the filename. */ name = (char *) contents; buildid_offset = strlen (name) + 1; - buildid_offset = (buildid_offset + 3) & ~3; - * buildid_out = bfd_get_32 (abfd, contents + buildid_offset); + *buildid_len = bfd_get_section_size (sect) - buildid_offset; + *buildid_out = bfd_malloc (*buildid_len); + memcpy (*buildid_out, contents + buildid_offset, *buildid_len); return name; } @@ -1466,6 +1471,24 @@ bfd_follow_gnu_debuglink (bfd *abfd, const char *dir) separate_debug_file_exists); } +/* Helper for bfd_follow_gnu_debugaltlink. It just pretends to return + a CRC. .gnu_debugaltlink supplies a build-id, which is different, + but this is ok because separate_alt_debug_file_exists ignores the + CRC anyway. */ + +static char * +get_alt_debug_link_info_shim (bfd * abfd, unsigned long *crc32_out) +{ + size_t len; + bfd_byte *buildid = NULL; + char *result = bfd_get_alt_debug_link_info (abfd, &len, &buildid); + + *crc32_out = 0; + free (buildid); + + return result; +} + /* FUNCTION bfd_follow_gnu_debugaltlink @@ -1496,7 +1519,7 @@ char * bfd_follow_gnu_debugaltlink (bfd *abfd, const char *dir) { return find_separate_debug_file (abfd, dir, - bfd_get_alt_debug_link_info, + get_alt_debug_link_info_shim, separate_alt_debug_file_exists); } -- cgit v1.2.1