[clang] Only use major version in resource dir

[tbaeder]

Summary

As discussed in https://discourse.llvm.org/t/should-we-continue-embed-the-full-llvm-version-in-lib-clang/62094/8

Release note update still missing of course.

[mgorny]

To be honest, I've never seen much purpose in the x.y.z directory naming and I feel like it's making packaging unnecessarily more complex, at least for us in Gentoo.

That said, I'd personally prefer if the directory was entirely configurable just like CLANG_RESOURCE_DIR can specify arbitrary path right now. But I'm also fine with this as-is.

Adding some more people who may have an opinion.

[serge-sans-paille]

The consensus in the discourse thread you mention is not super strong, but I tend to agree with that patch. +1 for me.

[sylvestre.ledru]

i hope not too many people rely on it.
LGTM but please add it to the release notes

[MaskRay]

LGTM. Considering https://discourse.llvm.org/t/should-we-continue-embed-the-full-llvm-version-in-lib-clang/62094 and this thread, I think overall people favor this patch.

If a distribution wants to provide 16.0 and 16.1 simultaneously, the two installations can be in different install prefixes :)

[tbaeder]

Add a release note

[tbaeder]

I'm worried that this is gonna break build bots. Has anyone seen the ThreadSanitizer timeout reported by the precommit-ci before?

[tstellar]

@tbaeder That CI failure seems unrelated. Maybe just commit early in the day so you have time to deal with the bot failures (if any).

clang/docs/ReleaseNotes.rst

.. code-block:: c++
     template <typename T, typename... U> void g(T, U...);
     void h() {
       // This is rejected due to ambiguity between the pack and the
       // default argument. Only parameters with arguments are considered during
       // partial ordering of function templates.
       g(42);
     }
 
+- Clang's resource dir used to include the full clang version. It will now
+  include only the major version. The new resource directory is
+  ``$prefix/lib/clang/$CLANG_MAJOR_VERSION`` and can be queried using
+  ``clang -print-resource-dir``, just like before.
+
 What's New in Clang |release|?
 ==============================
 Some of the major new features and improvements to Clang are listed
 here. Generic improvements to Clang as a whole or to its underlying
 infrastructure are described first, followed by language-specific
 sections with improvements to Clang's support for those languages.
 
 Major New Features

clang/include/clang/Basic/Version.inc.in

 #define CLANG_VERSION @CLANG_VERSION@
 #define CLANG_VERSION_STRING "@CLANG_VERSION@"
 #define CLANG_VERSION_MAJOR @CLANG_VERSION_MAJOR@
+#define CLANG_VERSION_MAJOR_STRING "@CLANG_VERSION_MAJOR@"
 #define CLANG_VERSION_MINOR @CLANG_VERSION_MINOR@
 #define CLANG_VERSION_PATCHLEVEL @CLANG_VERSION_PATCHLEVEL@

clang/lib/Driver/Driver.cpp

std::string Driver::GetResourcesPath(StringRef BinaryPath,
   } else {
     // On Windows, libclang.dll is in bin/.
     // On non-Windows, libclang.so/.dylib is in lib/.
     // With a static-library build of libclang, LibClangPath will contain the
     // path of the embedding binary, which for LLVM binaries will be in bin/.
     // ../lib gets us to lib/ in both cases.
     P = llvm::sys::path::parent_path(Dir);
     llvm::sys::path::append(P, CLANG_INSTALL_LIBDIR_BASENAME, "clang",
-                            CLANG_VERSION_STRING);
+                            CLANG_VERSION_MAJOR_STRING);
   }
 
   return std::string(P.str());
 }
 
 Driver::Driver(StringRef ClangExecutable, StringRef TargetTriple,
                DiagnosticsEngine &Diags, std::string Title,
                IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS)

clang/lib/Headers/CMakeLists.txt

set(openmp_wrapper_files
   openmp_wrappers/cmath
   openmp_wrappers/complex.h
   openmp_wrappers/complex
   openmp_wrappers/__clang_openmp_device_functions.h
   openmp_wrappers/complex_cmath.h
   openmp_wrappers/new
 )
 
-set(output_dir ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}/include)
+set(output_dir ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION_MAJOR}/include)
 set(out_files)
 set(generated_files)
 
 set(arm_common_generated_files)
 set(arm_only_generated_files)
 set(aarch64_only_generated_files)
 set(riscv_generated_files)
 

 
 # Other header groupings
 add_header_target("hlsl-resource-headers" ${hlsl_files})
 add_header_target("opencl-resource-headers" ${opencl_files})
 add_header_target("openmp-resource-headers" ${openmp_wrapper_files})
 add_header_target("windows-resource-headers" ${windows_only_files})
 add_header_target("utility-resource-headers" ${utility_files})
 
-set(header_install_dir lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/include)
+set(header_install_dir lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION_MAJOR}/include)
 
 #############################################################
 # Install rules for the catch-all clang-resource-headers target
 install(
   FILES ${files} ${generated_files}
   DESTINATION ${header_install_dir}
   COMPONENT clang-resource-headers)
 

clang/lib/Tooling/CMakeLists.txt

else()
   add_custom_command(
       COMMENT Generate ASTNodeAPI.json
       OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/ASTNodeAPI.json
       DEPENDS clang-ast-dump clang-resource-headers
       COMMAND
       $<TARGET_FILE:clang-ast-dump>
         # Skip this in debug mode because parsing AST.h is too slow
         --skip-processing=${skip_expensive_processing}
-        -I ${LLVM_BINARY_DIR}/lib/clang/${CLANG_VERSION}/include
+        -I ${LLVM_BINARY_DIR}/lib/clang/${CLANG_VERSION_MAJOR}/include
         -I ${CLANG_SOURCE_DIR}/include
         -I ${LLVM_BINARY_DIR}/tools/clang/include
         -I ${LLVM_BINARY_DIR}/include
         -I ${LLVM_SOURCE_DIR}/include
         ${implicitDirs}
         --json-output-path ${CMAKE_CURRENT_BINARY_DIR}/ASTNodeAPI.json
   )
 

clang/runtime/CMakeLists.txt

CMAKE_ARGS ${CLANG_COMPILER_RT_CMAKE_ARGS}
                -DCMAKE_CXX_COMPILER=${LLVM_RUNTIME_OUTPUT_INTDIR}/clang++
                -DCMAKE_ASM_COMPILER=${LLVM_RUNTIME_OUTPUT_INTDIR}/clang
                -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
                -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
                -DCMAKE_C_COMPILER_LAUNCHER=${CMAKE_C_COMPILER_LAUNCHER}
                -DCMAKE_CXX_COMPILER_LAUNCHER=${CMAKE_CXX_COMPILER_LAUNCHER}
                -DLLVM_CONFIG_PATH=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-config
                -DLLVM_LIT_ARGS=${LLVM_LIT_ARGS}
-               -DCOMPILER_RT_OUTPUT_DIR=${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}
+               -DCOMPILER_RT_OUTPUT_DIR=${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION_MAJOR}
                -DCOMPILER_RT_EXEC_OUTPUT_DIR=${LLVM_RUNTIME_OUTPUT_INTDIR}
-               -DCOMPILER_RT_INSTALL_PATH:PATH=lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}
+               -DCOMPILER_RT_INSTALL_PATH:PATH=lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION_MAJOR}
                -DCOMPILER_RT_INCLUDE_TESTS=${LLVM_INCLUDE_TESTS}
                -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
                -DLLVM_LIBDIR_SUFFIX=${LLVM_LIBDIR_SUFFIX}
                -DLLVM_RUNTIME_OUTPUT_INTDIR=${LLVM_RUNTIME_OUTPUT_INTDIR}
                -DCMAKE_OSX_DEPLOYMENT_TARGET=${CMAKE_OSX_DEPLOYMENT_TARGET}
                -DCMAKE_OSX_SYSROOT:PATH=${CMAKE_OSX_SYSROOT}
                ${COMPILER_RT_PASSTHROUGH_VARIABLES}
     INSTALL_COMMAND ""

compiler-rt/cmake/base-config-ix.cmake

 # Setting these variables from an LLVM build is sufficient that compiler-rt can
 # construct the output paths, so it can behave as if it were in-tree here.
 if (LLVM_LIBRARY_OUTPUT_INTDIR AND LLVM_RUNTIME_OUTPUT_INTDIR AND PACKAGE_VERSION)
   set(LLVM_TREE_AVAILABLE On)
 endif()
 
 if (LLVM_TREE_AVAILABLE)
   # Compute the Clang version from the LLVM version.
-  # FIXME: We should be able to reuse CLANG_VERSION variable calculated
+  # FIXME: We should be able to reuse CLANG_VERSION_MAJOR variable calculated
   #        in Clang cmake files, instead of copying the rules here.
-  string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION
+  string(REGEX MATCH "^[0-9]+" CLANG_VERSION_MAJOR
          ${PACKAGE_VERSION})
   # Setup the paths where compiler-rt runtimes and headers should be stored.
-  set(COMPILER_RT_OUTPUT_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION})
+  set(COMPILER_RT_OUTPUT_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION_MAJOR})
   set(COMPILER_RT_EXEC_OUTPUT_DIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
-  set(COMPILER_RT_INSTALL_PATH lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION})
+  set(COMPILER_RT_INSTALL_PATH lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION_MAJOR})
   option(COMPILER_RT_INCLUDE_TESTS "Generate and build compiler-rt unit tests."
          ${LLVM_INCLUDE_TESTS})
   option(COMPILER_RT_ENABLE_WERROR "Fail and stop if warning is triggered"
          ${LLVM_ENABLE_WERROR})
 
   # Use just-built Clang to compile/link tests on all platforms.
   if (CMAKE_CROSSCOMPILING)
     if (CMAKE_HOST_WIN32)

lldb/source/Plugins/ExpressionParser/Clang/ClangHost.cpp

static bool DefaultComputeClangResourceDirectory(FileSpec &lldb_shlib_spec,
                                                  bool verify) {
   Log *log = GetLog(LLDBLog::Host);
   std::string raw_path = lldb_shlib_spec.GetPath();
   llvm::StringRef parent_dir = llvm::sys::path::parent_path(raw_path);
 
   static const llvm::StringRef kResourceDirSuffixes[] = {
       // LLVM.org's build of LLDB uses the clang resource directory placed
       // in $install_dir/lib{,64}/clang/$clang_version.
-      CLANG_INSTALL_LIBDIR_BASENAME "/clang/" CLANG_VERSION_STRING,
+      CLANG_INSTALL_LIBDIR_BASENAME "/clang/" CLANG_VERSION_MAJOR_STRING,
       // swift-lldb uses the clang resource directory copied from swift, which
       // by default is placed in $install_dir/lib{,64}/lldb/clang. LLDB places
       // it there, so we use LLDB_INSTALL_LIBDIR_BASENAME.
       LLDB_INSTALL_LIBDIR_BASENAME "/lldb/clang",
   };
 
   for (const auto &Suffix : kResourceDirSuffixes) {
     llvm::SmallString<256> clang_dir(parent_dir);

lldb/unittests/Expression/ClangParserTest.cpp

static std::string ComputeClangResourceDir(std::string lldb_shlib_path,
   ComputeClangResourceDirectory(lldb_shlib_spec, clang_dir, verify);
   return clang_dir.GetPath();
 }
 
 TEST_F(ClangHostTest, ComputeClangResourceDirectory) {
 #if !defined(_WIN32)
   std::string path_to_liblldb = "/foo/bar/lib/";
   std::string path_to_clang_dir =
-      "/foo/bar/" LLDB_INSTALL_LIBDIR_BASENAME "/clang/" CLANG_VERSION_STRING;
+      "/foo/bar/" LLDB_INSTALL_LIBDIR_BASENAME "/clang/" CLANG_VERSION_MAJOR_STRING;
 #else
   std::string path_to_liblldb = "C:\\foo\\bar\\lib";
-  std::string path_to_clang_dir = "C:\\foo\\bar\\lib\\clang\\" CLANG_VERSION_STRING;
+  std::string path_to_clang_dir =
+      "C:\\foo\\bar\\lib\\clang\\" CLANG_VERSION_MAJOR_STRING;
 #endif
   EXPECT_EQ(ComputeClangResourceDir(path_to_liblldb), path_to_clang_dir);
 
   // The path doesn't really exist, so setting verify to true should make
   // ComputeClangResourceDir not give you path_to_clang_dir.
   EXPECT_NE(ComputeClangResourceDir(path_to_liblldb, true), path_to_clang_dir);
 }
 

llvm/cmake/modules/LLVMExternalProjectUtils.cmake

set(compiler_args -DCMAKE_ASM_COMPILER=${CMAKE_ASM_COMPILER}
                       -DCMAKE_NM=${CMAKE_NM}
                       -DCMAKE_OBJCOPY=${CMAKE_OBJCOPY}
                       -DCMAKE_OBJDUMP=${CMAKE_OBJDUMP}
                       -DCMAKE_STRIP=${CMAKE_STRIP}
                       -DCMAKE_READELF=${CMAKE_READELF})
     set(llvm_config_path ${LLVM_CONFIG_PATH})
 
     if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-      string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION
+      string(REGEX MATCH "^[0-9]+" CLANG_VERSION_MAJOR
              ${PACKAGE_VERSION})
-      set(resource_dir "${LLVM_LIBRARY_DIR}/clang/${CLANG_VERSION}")
+      set(resource_dir "${LLVM_LIBRARY_DIR}/clang/${CLANG_VERSION_MAJOR}")
       set(flag_types ASM C CXX MODULE_LINKER SHARED_LINKER EXE_LINKER)
       foreach(type ${flag_types})
         set(${type}_flag -DCMAKE_${type}_FLAGS=-resource-dir=${resource_dir})
       endforeach()
       string(REPLACE ";" "|" flag_string "${flag_types}")
       foreach(arg ${ARG_CMAKE_ARGS})
         if(arg MATCHES "^-DCMAKE_(${flag_string})_FLAGS")
           foreach(type ${flag_types})

polly/lib/External/isl/interface/extract_interface.cc

static llvm::cl::list<string> Includes("I",
       llvm::cl::value_desc("path"), llvm::cl::Prefix);
 
 static llvm::cl::opt<string> OutputLanguage(llvm::cl::Required,
   llvm::cl::ValueRequired, "language",
   llvm::cl::desc("Bindings to generate"),
   llvm::cl::value_desc("name"));
 
 static const char *ResourceDir =
-  CLANG_PREFIX "/lib/clang/" CLANG_VERSION_STRING;
+    CLANG_PREFIX "/lib/clang/" CLANG_VERSION_MAJOR_STRING;
 
 /* Does decl have an attribute of the following form?
  *
  *  __attribute__((annotate("name")))
  */
 bool has_annotation(Decl *decl, const char *name)
 {
   if (!decl->hasAttrs())