CMake: Improve default value of COMPILER_RT_LIBDIR_OS on non-Mac Posix

.github/workflows/main.yml

@@ -36,8 +36,6 @@ jobs:
           - job_name: Linux aarch64
             os: ubuntu-22.04-arm
             arch: aarch64
-            base_cmake_flags: >-
-              -DCOMPILER_RT_LIBDIR_OS=aarch64-unknown-linux-gnu
             extra_cmake_flags: >-
               -DCMAKE_C_COMPILER=clang
               -DCMAKE_CXX_COMPILER=clang++
@@ -52,7 +50,6 @@ jobs:
             container_image: alpine:3.21
             arch: x86_64
             base_cmake_flags: >-
-              -DCOMPILER_RT_LIBDIR_OS=linux
               -DLDC_INSTALL_LLVM_RUNTIME_LIBS_ARCH=x86_64
               -DLLVM_IS_SHARED=OFF
               -DLDC_ENABLE_PLUGINS=OFF
@@ -261,7 +258,6 @@ jobs:
             arch: aarch64
             android_x86_arch: x86_64
             extra_cmake_flags: >-
-              -DCOMPILER_RT_LIBDIR_OS=linux
               -DLDC_INSTALL_LLVM_RUNTIME_LIBS_ARCH=aarch64-android
 
     name: ${{ matrix.job_name }}

CMakeLists.txt

@@ -822,13 +822,25 @@ endif()
 set(COMPILER_RT_LIBDIR "${COMPILER_RT_LIBDIR}/lib")
 if(APPLE)
     set(COMPILER_RT_LIBDIR "${COMPILER_RT_LIBDIR}/darwin")
+elseif(ANDROID)
+    set(COMPILER_RT_LIBDIR "${COMPILER_RT_LIBDIR}/linux")
 elseif(UNIX)
-    set(COMPILER_RT_LIBDIR_OS_DEFAULT "x86_64-unknown-linux-gnu")
+    set(COMPILER_RT_LIBDIR_OS_DEFAULT "${LLVM_HOST_TARGET}") # default when building compiler-rt alongside LLVM
+    if(NOT EXISTS "${COMPILER_RT_LIBDIR}/${COMPILER_RT_LIBDIR_OS_DEFAULT}")
+        # default when building compiler-rt separately: OS name alone in lowercase
+        string(TOLOWER "${CMAKE_SYSTEM_NAME}" lowercase_CMAKE_SYSTEM_NAME)
+        if(EXISTS "${COMPILER_RT_LIBDIR}/${lowercase_CMAKE_SYSTEM_NAME}")
+            set(COMPILER_RT_LIBDIR_OS_DEFAULT "${lowercase_CMAKE_SYSTEM_NAME}")
+        endif()
+    endif()
     set(COMPILER_RT_LIBDIR_OS "${COMPILER_RT_LIBDIR_OS_DEFAULT}"   CACHE STRING "Non-Mac Posix: OS used as directory name for the compiler-rt source libraries, e.g., 'freebsd'.")
     set(COMPILER_RT_LIBDIR "${COMPILER_RT_LIBDIR}/${COMPILER_RT_LIBDIR_OS}")
 elseif(WIN32)
     set(COMPILER_RT_LIBDIR "${COMPILER_RT_LIBDIR}/windows")
 endif()
+if(NOT EXISTS "${COMPILER_RT_LIBDIR}")
+    message(WARNING "Expected compiler-rt directory '${COMPILER_RT_LIBDIR}' does not exist. To include PGO and sanitizers support, please set COMPILER_RT_LIBDIR_OS to the correct last component of this path.")
+endif()
 if(LLVM_IS_SHARED)
     set(LDC_INSTALL_LLVM_RUNTIME_LIBS_DEFAULT OFF)
 else()

cmake/Modules/FindLLVM.cmake

@@ -142,6 +142,7 @@ else()
     llvm_set(INCLUDE_DIRS includedir true)
     llvm_set(ROOT_DIR prefix true)
     llvm_set(ENABLE_ASSERTIONS assertion-mode)
+    llvm_set(HOST_TARGET host-target)
 
     # The LLVM version string _may_ contain a git/svn suffix, so match only the x.y.z part
     string(REGEX MATCH "^[0-9]+[.][0-9]+[.][0-9]+" LLVM_VERSION_BASE_STRING "${LLVM_VERSION_STRING}")

driver/linker-gcc.cpp

@@ -243,8 +243,9 @@ bool ArgsBuilder::isLldDefaultLinker() {
 // Returns the arch name as used in the compiler_rt libs.
 // FIXME: implement correctly for non-x86 platforms (e.g. ARM)
 // See clang/lib/Driver/Toolchain.cpp.
-llvm::StringRef getCompilerRTArchName(const llvm::Triple &triple) {
-  return triple.getArchName();
+std::string getCompilerRTArchName(const llvm::Triple &triple) {
+  llvm::StringRef archName = triple.getArchName();
+  return (triple.isAndroid() ? archName + "-android" : archName).str();
 }
 
 // Appends arch suffix and extension.
@@ -269,26 +270,36 @@ std::string getCompilerRTLibFilename(const llvm::Twine &name,
 // See clang/lib/Driver/Toolchain.cpp.
 std::vector<std::string> getRelativeClangCompilerRTLibPath(
     const llvm::Twine &name, const llvm::Triple &triple, bool sharedLibrary) {
-  llvm::StringRef OSName = triple.isOSDarwin()    ? "darwin"
-                           : triple.isOSFreeBSD() ? "freebsd"
-                                                  : triple.getOSName();
-
   auto llvm_major_version =
       llvm::StringRef(ldc::llvm_version_base).take_until([](char c) {
         return c == '.';
       });
+  LLSmallVector<llvm::StringRef, 2> llvmVersionCandidates = {
+      ldc::llvm_version_base, llvm_major_version};
 
-  std::string relPath = (llvm::Twine("clang/") + ldc::llvm_version_base +
-                         "/lib/" + OSName + "/" + name)
-                            .str();
-  std::string relPath_llvm_major_version =
-      (llvm::Twine("clang/") + llvm_major_version + "/lib/" + OSName + "/" +
-       name)
-          .str();
+  LLSmallVector<llvm::StringRef, 2> osNameCandidates;
+  if (triple.isOSDarwin()) {
+    osNameCandidates.emplace_back("darwin");
+  } else if (triple.isAndroid()) {
+    osNameCandidates.emplace_back("linux");
+  } else {
+    osNameCandidates.emplace_back(triple.str());
+    // using getOSTypeName() to avoid any OS version substring
+    osNameCandidates.emplace_back(llvm::Triple::getOSTypeName(triple.getOS()));
+  }
 
-  return {getCompilerRTLibFilename(relPath, triple, sharedLibrary),
-          getCompilerRTLibFilename(relPath_llvm_major_version, triple,
-                                   sharedLibrary)};
+  std::vector<std::string> r;
+  for (auto osName : osNameCandidates) {
+    for (auto llvmVersion : llvmVersionCandidates) {
+      std::string relPath =
+          (llvm::Twine("clang/") + llvmVersion + "/lib/" + osName + "/" + name)
+              .str();
+
+      r.push_back(getCompilerRTLibFilename(relPath, triple, sharedLibrary));
+    }
+  }
+
+  return r;
 }
 
 void appendFullLibPathCandidates(std::vector<std::string> &paths,