[PATCH] D109719: [runtimes] Check whether -nostdinc++ and -nostdlib++ are supported

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo created this revision.
mstorsjo added a reviewer: phosek.
Herald added a subscriber: mgorny.
mstorsjo requested review of this revision.
Herald added a project: LLVM.

Don't blindly assume they're supported - GCC doesn't support -nostdlib++.

The llvm-project/runtimes directory is supposed to allow building the
runtimes standalone from a newly built Clang, and thus should allow
building with other compilers too.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D109719

Files:
  runtimes/CMakeLists.txt


Index: runtimes/CMakeLists.txt
===================================================================
--- runtimes/CMakeLists.txt
+++ runtimes/CMakeLists.txt
@@ -87,12 +87,16 @@
 
 include(CheckLibraryExists)
 include(CheckCCompilerFlag)
+include(CheckCXXCompilerFlag)
 
-# Disable use of the installed C++ standard library when building runtimes. If
-# MSVC is true, we must be using the clang-cl driver, which doesn't understand
-# these flags.
-if (NOT MSVC)
-  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdinc++ -nostdlib++")
+# Disable use of the installed C++ standard library when building runtimes.
+check_cxx_compiler_flag(-nostdinc++ LLVM_RUNTIMES_SUPPORT_NOSTDINCXX_FLAG)
+if (LLVM_RUNTIMES_SUPPORT_NOSTDINCXX_FLAG)
+  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdinc++")
+endif()
+check_c_compiler_flag(-nostdlib++ LLVM_RUNTIMES_SUPPORT_NOSTDLIBXX_FLAG)
+if (LLVM_RUNTIMES_SUPPORT_NOSTDLIBXX_FLAG)
+  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++")
 endif()
 
 # Avoid checking whether the compiler is working.


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