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| author | Alan Modra <amodra@gmail.com> | 2018-09-11 23:50:15 +0930 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2018-09-14 21:21:28 +0930 |
| commit | a4cd947aca23d58966ead843e120f4c19db01030 (patch) | |
| tree | ce6ff23107b69400deda148ed6eac20e4f7312c9 /bfd/reloc.c | |
| parent | 556059dd13a8a9a30b23eacbefbe7b85e74ce7b7 (diff) | |
| download | gdb-a4cd947aca23d58966ead843e120f4c19db01030.zip gdb-a4cd947aca23d58966ead843e120f4c19db01030.tar.gz gdb-a4cd947aca23d58966ead843e120f4c19db01030.tar.bz2 | |
PR23425, unresolved symbol diagnostic
dwarf2.c code reasonably assumes that debug info is local to a file,
an assumption now violated by gcc, resulting in "DWARF error: invalid
abstract instance DIE ref" or wrong details when attempting to print
linker error messages with file, function and line reported.
This is because find_abstract_instance is only prepared to handle
DW_FORM_ref_addr when the .debug_info section referenced is in the
current file. When that isn't the case, relocations to access another
file's .debug_info will typically be against a symbol defined at the
start of that .debug_info section, plus an addend. Since the dwarf2.c
code only considers the current file's debug info, that symbol will be
undefined, resolving to zero. In effect the ref_addr will wrongly
resolve to the current file's .debug_info.
This patch avoids the problem by treating relocations in debug
sections against undefined symbols in a similar manner to the way
relocations against symbols defined in discarded sections are
resolved. They result in a zero value (except in .debug_ranges)
regardless of the addend.
PR 23425
* reloc.c (bfd_generic_get_relocated_section_contents): Zero reloc
fields in debug sections when reloc is against an undefined symbol
and called from bfd_simple_get_relocated_section_contents or
similar.
* dwarf2.c (find_abstract_instance): Return true for zero offset
DW_FORM_ref_addr without returning values.
Diffstat (limited to 'bfd/reloc.c')
| -rw-r--r-- | bfd/reloc.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/bfd/reloc.c b/bfd/reloc.c index eba6091..6745741 100644 --- a/bfd/reloc.c +++ b/bfd/reloc.c @@ -8259,7 +8259,18 @@ bfd_generic_get_relocated_section_contents (bfd *abfd, goto error_return; } - if (symbol->section && discarded_section (symbol->section)) + /* Zap reloc field when the symbol is from a discarded + section, ignoring any addend. Do the same when called + from bfd_simple_get_relocated_section_contents for + undefined symbols in debug sections. This is to keep + debug info reasonably sane, in particular so that + DW_FORM_ref_addr to another file's .debug_info isn't + confused with an offset into the current file's + .debug_info. */ + if ((symbol->section != NULL && discarded_section (symbol->section)) + || (symbol->section == bfd_und_section_ptr + && (input_section->flags & SEC_DEBUGGING) != 0 + && link_info->input_bfds == link_info->output_bfd)) { bfd_byte *p; static reloc_howto_type none_howto |