[all-commits] [llvm/llvm-project] 489a73: [ELF] Fix a null pointer dereference when --emit-r...

[Fangrui Song via All-commits]

  Branch: refs/heads/release/10.x
  Home:   https://github.com/llvm/llvm-project
  Commit: 489a7356cca373de761ada4c06c5b43edc581b4b
      https://github.com/llvm/llvm-project/commit/489a7356cca373de761ada4c06c5b43edc581b4b
  Author: Fangrui Song <maskray at google.com>
  Date:   2020-04-10 (Fri, 10 Apr 2020)

  Changed paths:
    M lld/ELF/Driver.cpp
    M lld/ELF/InputSection.cpp
    M lld/ELF/InputSection.h
    A lld/test/ELF/emit-relocs-debug.s

  Log Message:
  -----------
  [ELF] Fix a null pointer dereference when --emit-relocs and --strip-debug are used together

Fixes https://bugs.llvm.org//show_bug.cgi?id=44878

When --strip-debug is specified, .debug* are removed from inputSections
while .rel[a].debug* (incorrectly) remain.

LinkerScript::addOrphanSections() requires the output section of a relocated
InputSectionBase to be created first.

.debug* are not in inputSections ->
output sections .debug* are not created ->
getOutputSectionName(.rel[a].debug*) dereferences a null pointer.

Fix the null pointer dereference by deleting .rel[a].debug* from inputSections as well.

Reviewed By: grimar, nickdesaulniers

Differential Revision: https://reviews.llvm.org/D74510

(cherry picked from commit 6c73246179376442705b3a545f4e1f1478777a04)