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authorTom Tromey <tromey@redhat.com>2013-10-08 19:56:15 +0000
committerTom Tromey <tromey@redhat.com>2013-10-08 19:56:15 +0000
commitdc294be54c96414035eed7d53dafdea0a6f31a72 (patch)
treee2ec6dd2f5754858a562b4b7105ab16fd5b302af /gdb/build-id.h
parent5bb7df2edfeb80282ce424bc0d32f07713e24220 (diff)
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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.
Diffstat (limited to 'gdb/build-id.h')
-rw-r--r--gdb/build-id.h44
1 files changed, 44 insertions, 0 deletions
diff --git a/gdb/build-id.h b/gdb/build-id.h
new file mode 100644
index 0000000..b3ea4fb
--- /dev/null
+++ b/gdb/build-id.h
@@ -0,0 +1,44 @@
+/* build-id-related functions.
+
+ Copyright (C) 1991-2013 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef BUILD_ID_H
+#define BUILD_ID_H
+
+/* Return true if ABFD has NT_GNU_BUILD_ID matching the CHECK value.
+ Otherwise, issue a warning and return false. */
+
+extern int build_id_verify (bfd *abfd,
+ size_t check_len, const bfd_byte *check);
+
+
+/* Find and open a BFD given a build-id. If no BFD can be found,
+ return NULL. The returned reference to the BFD must be released by
+ the caller. */
+
+extern bfd *build_id_to_debug_bfd (size_t build_id_len,
+ const bfd_byte *build_id);
+
+/* Find the separate debug file for OBJFILE, by using the build-id
+ associated with OBJFILE's BFD. If successful, returns a malloc'd
+ file name for the separate debug file. The caller must free this.
+ Otherwise, returns NULL. */
+
+extern char *find_separate_debug_file_by_buildid (struct objfile *objfile);
+
+#endif /* BUILD_ID_H */