[Openmp-commits] [openmp] Avoid concurrency issues in LibompGetArchitecture (PR #151313)

[Alexander Grund via Openmp-commits]

https://github.com/Flamefire created https://github.com/llvm/llvm-project/pull/151313

Especially during `make check-all -j <n>` this CMake code might be run in parallel. So one process could remove the file another process has just written and tries to compile.

So do not delete the file.

Additionally use just `try_compile` as running is never intended nor possible anyway.


Note: Another solution could be to just extract the embedded file to a plain file in the same folder and use that as the source.

>From 9458391911f89e7a03ce12bd329a8454020b375e Mon Sep 17 00:00:00 2001
From: Alexander Grund <Flamefire at users.noreply.github.com>
Date: Wed, 30 Jul 2025 13:31:46 +0200
Subject: [PATCH] Avoid concurrency issues in LibompGetArchitecture

Especially during `make check-all -j <n>` this CMake code might be run in parallel.
So one process could remove the file another process has just written and tries to compile.

So do not delete the file.
Additionally use just `try_compile` as running is never intended nor possible anyway.
---
 openmp/runtime/cmake/LibompGetArchitecture.cmake | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/openmp/runtime/cmake/LibompGetArchitecture.cmake b/openmp/runtime/cmake/LibompGetArchitecture.cmake
index 81aa700e3b6db..405bf99414241 100644
--- a/openmp/runtime/cmake/LibompGetArchitecture.cmake
+++ b/openmp/runtime/cmake/LibompGetArchitecture.cmake
@@ -71,7 +71,7 @@ function(libomp_get_architecture return_arch)
   file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/libomp_detect_arch.c" ${detect_arch_src_txt})
 
   # Try to compile using the C Compiler.  It will always error out with an #error directive, so store error output to ${local_architecture}
-  try_run(run_dummy compile_dummy "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/libomp_detect_arch.c" COMPILE_OUTPUT_VARIABLE local_architecture)
+  try_compile(compile_dummy "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/libomp_detect_arch.c" OUTPUT_VARIABLE local_architecture)
 
   # Match the important architecture line and store only that matching string in ${local_architecture}
   string(REGEX MATCH "ARCHITECTURE=([a-zA-Z0-9_]+)" local_architecture "${local_architecture}")
@@ -81,9 +81,6 @@ function(libomp_get_architecture return_arch)
 
   # set the return value to the architecture detected (e.g., 32e, 32, arm, ppc64, etc.)
   set(${return_arch} "${local_architecture}" PARENT_SCOPE)
-
-  # Remove ${detect_arch_src_txt} from cmake/ subdirectory
-  file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/libomp_detect_arch.c")
 endfunction()
 
 function(libomp_is_aarch64_a64fx return_is_aarch64_a64fx)