Compilation fails on Amazon Linux 2023 aarch64

[sebsto]

Trying to compile llvm-project on Amazon Linux 2023 aarch64 (Amazon Graviton CPUs) fails with

-- Check for working C compiler: /home/ec2-user/swift-project/build/buildbot_linux/llvm-linux-aarch64/./bin/clang - broken
CMake Error at /usr/share/cmake/Modules/CMakeTestCCompiler.cmake:69 (message):
  The C compiler

    "/home/ec2-user/swift-project/build/buildbot_linux/llvm-linux-aarch64/./bin/clang"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: /home/ec2-user/swift-project/build/buildbot_linux/llvm-linux-aarch64/tools/clang/runtime/compiler-rt-bins/CMakeFiles/CMakeTmp
    
    Run Build Command(s):/home/ec2-user/swift-project/build/buildbot_linux/ninja-build/ninja cmTC_a5c7b && [1/2][ 50%][0.033s] Building C object CMakeFiles/cmTC_a5c7b.dir/testCCompiler.c.o
    [2/2][100%][0.106s] Linking C executable cmTC_a5c7b
    FAILED: cmTC_a5c7b 
    : && /home/ec2-user/swift-project/build/buildbot_linux/llvm-linux-aarch64/./bin/clang   CMakeFiles/cmTC_a5c7b.dir/testCCompiler.c.o -o cmTC_a5c7b   && :
    /usr/bin/ld: cannot find crtbeginS.o: No such file or directory
    /usr/bin/ld: cannot find -lgcc: No such file or directory
    /usr/bin/ld: cannot find -lgcc_s: No such file or directory
    clang-13: error: linker command failed with exit code 1 (use -v to see invocation)
    ninja: build stopped: subcommand failed.
   
  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:10 (project)


-- Configuring incomplete, errors occurred!

This is because Amazon defined a new triplet to identify the platform : aarch64-amazon-linux

Solution seems to add the triplet in Gnu.cpp like this (diff generated from next branch):

diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index a2526a2b9039..3aa870d4c423 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -2456,7 +2456,7 @@ void Generic_GCC::GCCInstallationDetector::AddDefaultGCCPrefixes(
   static const char *const AArch64LibDirs[] = {"/lib64", "/lib"};
   static const char *const AArch64Triples[] = {
       "aarch64-none-linux-gnu", "aarch64-linux-gnu", "aarch64-redhat-linux",
-      "aarch64-suse-linux"};
+      "aarch64-suse-linux", "aarch64-amazon-linux"};
   static const char *const AArch64beLibDirs[] = {"/lib"};
   static const char *const AArch64beTriples[] = {"aarch64_be-none-linux-gnu",
                                                  "aarch64_be-linux-gnu"};

[sebsto]

Created a PR #8228