[all-commits] [llvm/llvm-project] 1ccde5: [ELF] --gdb-index: support .debug_loclists

[Fangrui Song via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 1ccde533425a4ba9d379510206ad680ff9702129
      https://github.com/llvm/llvm-project/commit/1ccde533425a4ba9d379510206ad680ff9702129
  Author: Fangrui Song <maskray at google.com>
  Date:   2020-04-29 (Wed, 29 Apr 2020)

  Changed paths:
    M lld/ELF/DWARF.cpp
    M lld/ELF/DWARF.h
    A lld/test/ELF/gdb-index-loclists.s

  Log Message:
  -----------
  [ELF] --gdb-index: support .debug_loclists

--gdb-index currently crashes when reading a translation unit with
DWARF v5 .debug_loclists . Call stack:

```
SyntheticSections.cpp GdbIndexSection::create
SyntheticSections.cpp readAddressAreas
DWARFUnit.cpp DWARFUnit::tryExtractDIEsIfNeeded
DWARFListTable.cpp DWARFListTableHeader::extract
...
DWARFDataExtractor.cpp DWARFDataExtractor::getRelocatedValue
lld/ELF/DWARF.cpp LLDDwarfObj<ELFT>::find (sec.sec is nullptr)
...

```

This patch adds support for .debug_loclists to make `DWARFUnit::tryExtractDIEsIfNeeded` happy.
Building --gdb-index does not need .debug_loclists

Reviewed By: dblaikie, grimar

Differential Revision: https://reviews.llvm.org/D79061