[all-commits] [llvm/llvm-project] 33b740: [CMake][compiler-rt][AArch64] Avoid preprocessing ...

[Raul Tambre via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 33b740f8dc3496237619a7bc6722f23655cb1f94
      https://github.com/llvm/llvm-project/commit/33b740f8dc3496237619a7bc6722f23655cb1f94
  Author: Raul Tambre <raul at tambre.ee>
  Date:   2020-12-14 (Mon, 14 Dec 2020)

  Changed paths:
    M compiler-rt/lib/builtins/CMakeLists.txt
    M compiler-rt/lib/builtins/aarch64/lse.S

  Log Message:
  -----------
  [CMake][compiler-rt][AArch64] Avoid preprocessing LSE builtins separately

Invoking the preprocessor ourselves is fragile and would require us to replicate CMake's handling of definitions, compiler flags, etc for proper compatibility.
In my toolchain builds this notably resulted in a bunch of warnings from unused flags as my CMAKE_C_FLAGS includes CPU-specific optimization options.
Notably this part was already duplicating the logic for VISIBILITY_HIDDEN define.

Instead, symlink the files and set the proper set of defines on each.
This should also be faster as we avoid invoking the compiler multiple times.

Fixes https://llvm.org/PR48494

Reviewed By: ilinpv

Differential Revision: https://reviews.llvm.org/D93178