[clang] Replace BACKEND_PACKAGE_STRING with LLVM_VERSION_STRING

[MaskRay]

Summary

420d7ccbac0f499a6ff9595bdbfa99cd3376df22 introduced BACKEND_PACKAGE_STRING to
replace PACKAGE_VERSION (llvm/Config/config.h) to support standalone builds.
This is used in the output of clang -cc1 -v.

Since llvm-config.h is available for both standalone and non-standalone builds,
we can just use LLVM_VERSION_STRING from llvm-config.h.

clang/cmake/modules/AddClang.cmake uses VERSION_STRING "${CLANG_VERSION} (${BACKEND_PACKAGE_STRING})".
Just simplify it to "${CLANG_VERSION}" so that we can remove the CMake
variable BACKEND_PACKAGE_STRING.

[tstellar]

This seems fine to me.

[mgorny]

I suppose you want to remove it from clang/CMakeLists.txt as well. I see Flang has copied the same logic too, so might be worthwhile to remove it there as well.

[MaskRay]

In D136660#3881602, @mgorny wrote:

I suppose you want to remove it from clang/CMakeLists.txt as well. I see Flang has copied the same logic too, so might be worthwhile to remove it there as well.

set(BACKEND_PACKAGE_STRING "LLVM ${LLVM_PACKAGE_VERSION}") and another set in clang/CMakeLists.txt is used by clang/cmake/modules/AddClang.cmake.
Perhaps just simplify VERSION_STRING "${CLANG_VERSION} (${BACKEND_PACKAGE_STRING})" to VERSION_STRING "${CLANG_VERSION}" ? The backend package string is probably not useful.

[MaskRay]

Remove cmake variable BACKEND_PACKAGE_STRING

[MaskRay]

Since the patch subject is called [clang] I am deferring the flang cmake change to a separate patch.

[mgorny]

In D136660#3881617, @MaskRay wrote:

In D136660#3881602, @mgorny wrote:

I suppose you want to remove it from clang/CMakeLists.txt as well. I see Flang has copied the same logic too, so might be worthwhile to remove it there as well.

set(BACKEND_PACKAGE_STRING "LLVM ${LLVM_PACKAGE_VERSION}") and another set in clang/CMakeLists.txt is used by clang/cmake/modules/AddClang.cmake.
Perhaps just simplify VERSION_STRING "${CLANG_VERSION} (${BACKEND_PACKAGE_STRING})" to VERSION_STRING "${CLANG_VERSION}" ? The backend package string is probably not useful.

Perhaps it was used to account for LLVM and Clang minor version mismatch — though I don't know if anyone is actually building a configuration like that.

[MaskRay]

In D136660#3881647, @mgorny wrote:

In D136660#3881617, @MaskRay wrote:

In D136660#3881602, @mgorny wrote:

I suppose you want to remove it from clang/CMakeLists.txt as well. I see Flang has copied the same logic too, so might be worthwhile to remove it there as well.

set(BACKEND_PACKAGE_STRING "LLVM ${LLVM_PACKAGE_VERSION}") and another set in clang/CMakeLists.txt is used by clang/cmake/modules/AddClang.cmake.
Perhaps just simplify VERSION_STRING "${CLANG_VERSION} (${BACKEND_PACKAGE_STRING})" to VERSION_STRING "${CLANG_VERSION}" ? The backend package string is probably not useful.

Perhaps it was used to account for LLVM and Clang minor version mismatch — though I don't know if anyone is actually building a configuration like that.

Yes, and that's used in a minor place for a Windows build... The LLVM version should really not matter.

clang/include/clang/Config/config.h.cmake

 #define GCC_INSTALL_PREFIX "${GCC_INSTALL_PREFIX}"
 
 /* Define if we have libxml2 */
 #cmakedefine CLANG_HAVE_LIBXML ${CLANG_HAVE_LIBXML}
 
 /* Define if we have sys/resource.h (rlimits) */
 #cmakedefine CLANG_HAVE_RLIMITS ${CLANG_HAVE_RLIMITS}
 
-/* The LLVM product name and version */
-#define BACKEND_PACKAGE_STRING "${BACKEND_PACKAGE_STRING}"
-
 /* Linker version detected at compile time. */
 #cmakedefine HOST_LINK_VERSION "${HOST_LINK_VERSION}"
 
 /* pass --build-id to ld */
 #cmakedefine ENABLE_LINKER_BUILD_ID
 
 /* enable x86 relax relocations by default */
 #cmakedefine01 ENABLE_X86_RELAX_RELOCATIONS

clang/lib/Frontend/CompilerInstance.cpp

 #include "clang/Lex/PreprocessorOptions.h"
 #include "clang/Sema/CodeCompleteConsumer.h"
 #include "clang/Sema/Sema.h"
 #include "clang/Serialization/ASTReader.h"
 #include "clang/Serialization/GlobalModuleIndex.h"
 #include "clang/Serialization/InMemoryModuleCache.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Config/llvm-config.h"
 #include "llvm/Support/BuryPointer.h"
 #include "llvm/Support/CrashRecoveryContext.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/LockFileManager.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
if (!createTarget())
     return false;
 
   // rewriter project will change target built-in bool type from its default.
   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
     getTarget().noSignedCharForObjCBool();
 
   // Validate/process some options.
   if (getHeaderSearchOpts().Verbose)
-    OS << "clang -cc1 version " CLANG_VERSION_STRING
-       << " based upon " << BACKEND_PACKAGE_STRING
-       << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
+    OS << "clang -cc1 version " CLANG_VERSION_STRING << " based upon LLVM "
+       << LLVM_VERSION_STRING << " default target "
+       << llvm::sys::getDefaultTargetTriple() << "\n";
 
   if (getCodeGenOpts().TimePasses)
     createFrontendTimer();
 
   if (getFrontendOpts().ShowStats || !getFrontendOpts().StatsFile.empty())
     llvm::EnableStatistics(false);
 
   for (const FrontendInputFile &FIF : getFrontendOpts().Inputs) {

llvm/utils/gn/secondary/clang/include/clang/Config/BUILD.gn

values = [
     "CLANG_OPENMP_NVPTX_DEFAULT_ARCH=sm_35",
     "CLANG_RESOURCE_DIR=",
     "C_INCLUDE_DIRS=",
     "CLANG_CONFIG_FILE_SYSTEM_DIR=",
     "CLANG_CONFIG_FILE_USER_DIR=",
     "CLANG_SPAWN_CC1=",
     "DEFAULT_SYSROOT=",
     "GCC_INSTALL_PREFIX=",
-    "BACKEND_PACKAGE_STRING=LLVM ${llvm_version}git",
     "ENABLE_LINKER_BUILD_ID=",
     "ENABLE_X86_RELAX_RELOCATIONS=1",
     "CLANG_ENABLE_OBJC_REWRITER=1",  # FIXME: flag?
     "CLANG_SYSTEMZ_DEFAULT_ARCH=z10",
     "PPC_LINUX_DEFAULT_IEEELONGDOUBLE=",
   ]
 
   if (clang_enable_arcmt) {

llvm/utils/release/bump-version.py

def process_line(self, line: str) -> str:
             ):
                 nline = re.sub(
                     fr"(LLVM|CLANG)_VERSION_{c} \d+",
                     rf"\g<1>_VERSION_\g<2> {cver}",
                     line,
                 )
                 if nline != line:
                     break
-        # Match the BACKEND_PACKAGE_STRING in clang/config.h
-        elif "BACKEND_PACKAGE_STRING" in line:
-            nline = re.sub(
-                r'#define BACKEND_PACKAGE_STRING "LLVM ([0-9\.rcgit-]+)"',
-                f'#define BACKEND_PACKAGE_STRING "LLVM {self.version_str()}"',
-                line,
-            )
 
         return nline
 
 
 # GN build system
 class GNIProcessor(Processor):
     def process_line(self, line: str) -> str:
         if "llvm_version_" in line:

utils/bazel/llvm-project-overlay/clang/include/clang/Config/config.h

 #define GCC_INSTALL_PREFIX ""
 
 /* Define if we have libxml2 */
 /* #undef CLANG_HAVE_LIBXML */
 
 /* Define if we have sys/resource.h (rlimits) */
 /* CLANG_HAVE_RLIMITS defined conditionally below */
 
-/* The LLVM product name and version */
-#define BACKEND_PACKAGE_STRING "LLVM 16.0.0git"
-
 /* Linker version detected at compile time. */
 /* #undef HOST_LINK_VERSION */
 
 /* pass --build-id to ld */
 /* #undef ENABLE_LINKER_BUILD_ID */
 
 /* enable x86 relax relocations by default */
 #define ENABLE_X86_RELAX_RELOCATIONS 1