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:
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.