[all-commits] [llvm/llvm-project] 78668c: [clang][modules][pch] Allow loading PCH with diffe...

[Jan Svoboda via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 78668c822af9504f77a554f5924e1097365d9c33
      https://github.com/llvm/llvm-project/commit/78668c822af9504f77a554f5924e1097365d9c33
  Author: Jan Svoboda <jan_svoboda at apple.com>
  Date:   2021-06-14 (Mon, 14 Jun 2021)

  Changed paths:
    M clang/include/clang/Driver/Options.td
    M clang/include/clang/Lex/PreprocessorOptions.h
    M clang/lib/Serialization/ASTReader.cpp
    A clang/test/Modules/Inputs/pch-typedef.h
    A clang/test/Modules/module-pch-different-cache-path.c

  Log Message:
  -----------
  [clang][modules][pch] Allow loading PCH with different modules cache path

It's useful to be able to load explicitly-built PCH files into an implicit build (e.g. during dependency scanning). That's currently impossible, since the explicitly-built PCH has an empty modules cache path, while the current compilation has (and needs to have) a valid path, triggering an error in the `PCHValidator`.

This patch adds a preprocessor option and command-line flag that can be used to omit this check.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D103802