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Find .plt section in object files generated by recent ld 

Code in ObjectFileELF::ParseTrampolineSymbols assumes that the sh_info
field of the .rel(a).plt section identifies the .plt section.

However, with recent GNU ld this is no longer true.  As a result of this:
https://sourceware.org/bugzilla/show_bug.cgi?id=18169
in object files generated with current linkers the sh_info field of
.rel(a).plt now points to the .got.plt section (or .got on some targets).

This causes LLDB to fail to identify any PLT stubs, causing a number of
test case failures.

This patch changes LLDB to simply always look for the .plt section by
name.  This should be safe across all linkers and targets.

Differential Revision: http://reviews.llvm.org/D18973

llvm-svn: 266316
This commit is contained in:
Ulrich Weigand 2016-04-14 14:36:29 +00:00
parent 7e8de59b90
commit bd5262629d
1 changed files with 5 additions and 5 deletions
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10
lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
View File

@ -2611,17 +2611,17 @@ ObjectFileELF::ParseTrampolineSymbols(Symtab *symbol_table,
{
assert(rel_hdr->sh_type == SHT_RELA || rel_hdr->sh_type == SHT_REL);
// The link field points to the associated symbol table. The info field
// points to the section holding the plt.
// The link field points to the associated symbol table.
user_id_t symtab_id = rel_hdr->sh_link;
user_id_t plt_id = rel_hdr->sh_info;
// If the link field doesn't point to the appropriate symbol name table then
// try to find it by name as some compiler don't fill in the link fields.
if (!symtab_id)
symtab_id = GetSectionIndexByName(".dynsym");
if (!plt_id)
plt_id = GetSectionIndexByName(".plt");
// Get PLT section. We cannot use rel_hdr->sh_info, since current linkers
// point that to the .got.plt or .got section instead of .plt.
user_id_t plt_id = GetSectionIndexByName(".plt");
if (!symtab_id || !plt_id)
return 0;