[all-commits] [llvm/llvm-project] 4061d9: [clangd] Fix crash-bug in preamble indexing when u...

[Adam Czachorowski via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 4061d9e42cff621462931ac7df9666806c77a237
      https://github.com/llvm/llvm-project/commit/4061d9e42cff621462931ac7df9666806c77a237
  Author: Adam Czachorowski <adamcz at google.com>
  Date:   2020-08-10 (Mon, 10 Aug 2020)

  Changed paths:
    M clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
    M clang-tools-extra/clangd/unittests/TestFS.h
    M clang-tools-extra/clangd/unittests/TestTU.cpp
    M clang-tools-extra/clangd/unittests/TestTU.h
    M clang/lib/Index/IndexingAction.cpp

  Log Message:
  -----------
  [clangd] Fix crash-bug in preamble indexing when using modules.

Summary:
When preamble contains #undef, indexing code finds the matching #define
and uses that during indexing. However, it would only look for local
definitions. If the macro was defined in a module, MacroInfo
would be nullptr and clangd would crash.

This change makes clangd ignore any #undef without a matching #define
inside the same TU.

The indexing of macros happens for preamble only, so then #undef must be
in the preamble, which is why we need two .h files in a test.

Note that clangd is currently not ready for module support, but this
brings us one step closer.

Reviewers: sammccall

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80525