[PATCH] D69825: [Clang][Driver] Re-use the calling process instead of creating a new process for the cc1 invocation

[Wenlei He via Phabricator via llvm-commits]

wenlei added a comment.

@aganea, @hans This patch broke response file expansion for preprocessor via `-Wp` - all our internal builds failed with this patch because we invoke clang with response file passed to preprocessor, e.g. `clang++ ... -Wp, at pp.rsp @cc.rsp`. Looks like we can't just call `ExecuteCC1Tool` directly, because response file expansion happens in `main`, so with this patch, `-Wp, at pp.rsp` won't be expanded properly.

repo:

  CLANG_SPAWN_CC1=0  clang++ -c  -Wp, at a.rsp  @a.rsp test.cpp
  
  error: error reading '@rr.rsp'
  1 error generated.

and it works with `CLANG_SPAWN_CC1=1`


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D69825/new/

https://reviews.llvm.org/D69825