[config] Remove vestigial LLVM_VERSION_INFO

[rnk]

Summary

This has been superseded by the llvm/Support/VCSRevision.h header. So
far as I can tell, nothing in the CMake build sets LLVM_VERSION_INFO. It
was always undefined, and the ifdefs using it were dead. However, CMake
is very flexible, so it's possible that I missed some ways to set this
variable. One could, for example, probably pass -DLLVM_VERSION_INFO=x on
the command line and get that through to configure_file, or set the
variable in an obscure way (set(${proj}_VERSION_INFO "x")). I'm
reasonably confident that isn't happening, but I'd like a second
opinion.

Update the Bazel and gn builds accordingly.

[tstellar]

LGTM.

[arphaman]

@rnk this is option is needed to vendor the Apple clang toolchain in Xcode. Unfortunately we don't have any references to it in the upstream llvm-project repo, but this is breaking our downstream integration. Can this be reverted?

[rnk]

In D126977#3590611, @arphaman wrote:

@rnk this is option is needed to vendor the Apple clang toolchain in Xcode. Unfortunately we don't have any references to it in the upstream llvm-project repo, but this is breaking our downstream integration. Can this be reverted?

I'd prefer not to, if possible, since changing config.h.cmake churns all three in-tree build systems and any out-of-tree build systems. You should be able to get the old behavior by appending your definition of LLVM_VERSION_INFO to PACKAGE_VERSION. Does that work for you? We actually had the same problem at Google, coincidentally, and that's what we did.

Were you using LLVM_VERSION_INFO to embed the VCS revision? If yes, and we want the open source tools to do this, we should have the CommandLine.cpp --version code use the VCSRevision.h header. I think this may interact badly with tablegen, since every update to git HEAD will then modify Support, which llvm-blgen uses, which will invalidate all tablegen runs. Maybe we can fix that somehow. It's a bunch of work, but that's probably the best, most proper solution.

Anyway, I think it's best if everyone tries to align their internal integrations as much as possible with what the open source build supports, and that we don't have config options like this that are only exercised by out of tree builds.

llvm/include/llvm/Config/config.h.cmake

 #cmakedefine HAVE____CHKSTK_MS ${HAVE____CHKSTK_MS}
 
 /* Linker version detected at compile time. */
 #cmakedefine HOST_LINK_VERSION "${HOST_LINK_VERSION}"
 
 /* Define if overriding target triple is enabled */
 #cmakedefine LLVM_TARGET_TRIPLE_ENV "${LLVM_TARGET_TRIPLE_ENV}"
 
-/* LLVM version information */
-#cmakedefine LLVM_VERSION_INFO "${LLVM_VERSION_INFO}"
-
 /* Whether tools show host and target info when invoked with --version */
 #cmakedefine01 LLVM_VERSION_PRINTER_SHOW_HOST_TARGET_INFO
 
 /* Define if libxml2 is supported on this platform. */
 #cmakedefine LLVM_ENABLE_LIBXML2 ${LLVM_ENABLE_LIBXML2}
 
 /* Define to the extension used for shared libraries, say, ".so". */
 #cmakedefine LTDL_SHLIB_EXT "${LTDL_SHLIB_EXT}"

llvm/lib/LTO/LTOCodeGenerator.cpp

 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
 #include "llvm/Transforms/IPO/WholeProgramDevirt.h"
 #include "llvm/Transforms/ObjCARC.h"
 #include "llvm/Transforms/Utils/ModuleUtils.h"
 #include <system_error>
 using namespace llvm;
 
 const char* LTOCodeGenerator::getVersionString() {
-#ifdef LLVM_VERSION_INFO
-  return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
-#else
   return PACKAGE_NAME " version " PACKAGE_VERSION;
-#endif
 }
 
 namespace llvm {
 cl::opt<bool> LTODiscardValueNames(
     "lto-discard-value-names",
     cl::desc("Strip names from Value during LTO (other than GlobalValue)."),
 #ifdef NDEBUG
     cl::init(true),

llvm/lib/Support/CommandLine.cpp

 public:
   void print() {
     raw_ostream &OS = outs();
 #ifdef PACKAGE_VENDOR
     OS << PACKAGE_VENDOR << " ";
 #else
     OS << "LLVM (http://llvm.org/):\n  ";
 #endif
-    OS << PACKAGE_NAME << " version " << PACKAGE_VERSION;
-#ifdef LLVM_VERSION_INFO
-    OS << " " << LLVM_VERSION_INFO;
-#endif
-    OS << "\n  ";
+    OS << PACKAGE_NAME << " version " << PACKAGE_VERSION << "\n  ";
 #if LLVM_IS_DEBUG_BUILD
     OS << "DEBUG build";
 #else
     OS << "Optimized build";
 #endif
 #ifndef NDEBUG
     OS << " with assertions";
 #endif

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

values = [
     "HAVE___MODDI3=",
     "HAVE___UDIVDI3=",
     "HAVE___UMODDI3=",
     "HAVE____CHKSTK=",
     "HAVE____CHKSTK_MS=",
     "HOST_LINK_VERSION=",
     "LIBPFM_HAS_FIELD_CYCLES=",
     "LLVM_TARGET_TRIPLE_ENV=",
-    "LLVM_VERSION_INFO=",
     "LLVM_VERSION_PRINTER_SHOW_HOST_TARGET_INFO=1",
     "LLVM_WINDOWS_PREFER_FORWARD_SLASH=",
     "PACKAGE_BUGREPORT=https://github.com/llvm/llvm-project/issues/",
     "PACKAGE_NAME=LLVM",
     "PACKAGE_STRING=LLVM ${llvm_version}git",
     "PACKAGE_VERSION=${llvm_version}git",
     "PACKAGE_VENDOR=",
     "LLVM_GISEL_COV_ENABLED=",

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

 enum_targets_gen(
     name = "target_mca_def_gen",
     src = "include/llvm/Config/TargetMCAs.def.in",
     out = "include/llvm/Config/TargetMCAs.def",
     macro_name = "TARGETMCA",
     targets = llvm_target_mcas,
 )
 
-# TODO: Need to replace this with something that actually extracts the git
-# commit from the LLVM source (submodule or http_archive).
-genrule(
-    name = "version_info_gen",
-    outs = ["include/llvm/Config/VersionInfo.h"],
-    cmd = "echo '#define LLVM_VERSION_INFO \"git\"' > $@",
-)
-
 template_rule(
     name = "abi_breaking_h_gen",
     src = "include/llvm/Config/abi-breaking.h.cmake",
     out = "include/llvm/Config/abi-breaking.h",
     substitutions = {
         # Define to enable checks that alter the LLVM C++ ABI
         "#cmakedefine01 LLVM_ENABLE_ABI_BREAKING_CHECKS": "#define LLVM_ENABLE_ABI_BREAKING_CHECKS 0",
 
         # Define to enable reverse iteration of unordered llvm containers
         "#cmakedefine01 LLVM_ENABLE_REVERSE_ITERATION": "#define LLVM_ENABLE_REVERSE_ITERATION 0",
     },
 )
 
 # To enable diff testing out of tree
 exports_files([
     "include/llvm/Config/config.h.cmake",
     "include/llvm/Config/llvm-config.h.cmake",
     "include/llvm/Config/abi-breaking.h.cmake",
 ])
 
 cc_library(
     name = "config",
     hdrs = [
-        "include/llvm/Config/VersionInfo.h",
         "include/llvm/Config/abi-breaking.h",
         "include/llvm/Config/llvm-config.h",
     ],
     copts = llvm_copts,
     defines = llvm_config_defines,
     includes = ["include"],
     textual_hdrs = [
         "include/llvm/Config/AsmParsers.def",

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

 /* #undef HOST_LINK_VERSION */
 
 /* Define if zlib compression is available */
 /* LLVM_ENABLE_ZLIB defined in Bazel */
 
 /* Define if overriding target triple is enabled */
 /* #undef LLVM_TARGET_TRIPLE_ENV */
 
-/* LLVM version information */
-/* #undef LLVM_VERSION_INFO */
-
 /* Whether tools show host and target info when invoked with --version */
 #define LLVM_VERSION_PRINTER_SHOW_HOST_TARGET_INFO 1
 
 /* Define if libxml2 is supported on this platform. */
 /* #undef LLVM_ENABLE_LIBXML2 */
 
 /* Define to the extension used for shared libraries, say, ".so". */
 /* LTDL_SHLIB_EXT defined in Bazel */

utils/bazel/llvm_configs/config.h.cmake

 #cmakedefine HAVE____CHKSTK_MS ${HAVE____CHKSTK_MS}
 
 /* Linker version detected at compile time. */
 #cmakedefine HOST_LINK_VERSION "${HOST_LINK_VERSION}"
 
 /* Define if overriding target triple is enabled */
 #cmakedefine LLVM_TARGET_TRIPLE_ENV "${LLVM_TARGET_TRIPLE_ENV}"
 
-/* LLVM version information */
-#cmakedefine LLVM_VERSION_INFO "${LLVM_VERSION_INFO}"
-
 /* Whether tools show host and target info when invoked with --version */
 #cmakedefine01 LLVM_VERSION_PRINTER_SHOW_HOST_TARGET_INFO
 
 /* Define if libxml2 is supported on this platform. */
 #cmakedefine LLVM_ENABLE_LIBXML2 ${LLVM_ENABLE_LIBXML2}
 
 /* Define to the extension used for shared libraries, say, ".so". */
 #cmakedefine LTDL_SHLIB_EXT "${LTDL_SHLIB_EXT}"