[clang] [llvm] Update llvm::Registry to work for LLVM shared library builds on windows (PR #109024)

Tue Oct 15 22:51:12 PDT 2024

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-aarch64-libcxx` running on `linaro-flang-aarch64-libcxx` while building `clang,llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/89/builds/8505

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-unified-tree) failure: build (failure)
...
334.480 [204/11/7018] Linking CXX shared library lib/libFortranLower.so.20.0git
334.488 [203/11/7019] Creating library symlink lib/libFortranLower.so
337.442 [203/10/7020] Building CXX object tools/clang/lib/ARCMigrate/CMakeFiles/obj.clangARCMigrate.dir/Transforms.cpp.o
341.192 [203/9/7021] Building CXX object tools/clang/tools/clang-scan-deps/CMakeFiles/clang-scan-deps.dir/ClangScanDeps.cpp.o
342.381 [203/8/7022] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaTemplate.cpp.o
342.732 [203/7/7023] Building CXX object tools/clang/tools/libclang/CMakeFiles/libclang.dir/CXExtractAPI.cpp.o
343.647 [203/6/7024] Building CXX object tools/clang/lib/StaticAnalyzer/Checkers/CMakeFiles/obj.clangStaticAnalyzerCheckers.dir/WebKit/RefCntblBaseVirtualDtorChecker.cpp.o
344.092 [203/5/7025] Building CXX object tools/clang/lib/StaticAnalyzer/Checkers/CMakeFiles/obj.clangStaticAnalyzerCheckers.dir/WebKit/UncountedCallArgsChecker.cpp.o
352.004 [203/4/7026] Building CXX object tools/clang/lib/StaticAnalyzer/Frontend/CMakeFiles/obj.clangStaticAnalyzerFrontend.dir/AnalysisConsumer.cpp.o
369.586 [203/3/7027] Building CXX object tools/flang/lib/FrontendTool/CMakeFiles/flangFrontendTool.dir/ExecuteCompilerInvocation.cpp.o
FAILED: tools/flang/lib/FrontendTool/CMakeFiles/flangFrontendTool.dir/ExecuteCompilerInvocation.cpp.o 
/usr/local/bin/c++ -DFLANG_INCLUDE_TESTS=1 -DFLANG_LITTLE_ENDIAN=1 -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/flang/lib/FrontendTool -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/lib/FrontendTool -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/flang/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/llvm/include -isystem /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/llvm/../mlir/include -isystem /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/mlir/include -isystem /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/clang/include -isystem /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/llvm/../clang/include -stdlib=libc++ -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -Werror -Wno-deprecated-copy -Wno-string-conversion -Wno-ctad-maybe-unsupported -Wno-unused-command-line-argument -Wstring-conversion           -Wcovered-switch-default -Wno-nested-anon-types -O3 -DNDEBUG -std=c++17 -fPIC  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT tools/flang/lib/FrontendTool/CMakeFiles/flangFrontendTool.dir/ExecuteCompilerInvocation.cpp.o -MF tools/flang/lib/FrontendTool/CMakeFiles/flangFrontendTool.dir/ExecuteCompilerInvocation.cpp.o.d -o tools/flang/lib/FrontendTool/CMakeFiles/flangFrontendTool.dir/ExecuteCompilerInvocation.cpp.o -c /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/lib/FrontendTool/ExecuteCompilerInvocation.cpp
In file included from ../llvm-project/flang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:20:
In file included from ../llvm-project/flang/include/flang/Frontend/FrontendPluginRegistry.h:19:
../llvm-project/llvm/include/llvm/Support/Registry.h:110:47: error: instantiation of variable 'llvm::Registry<Fortran::frontend::PluginParseTreeAction>::Head' required here, but no definition is available [-Werror,-Wundefined-var-template]
  110 |     static iterator begin() { return iterator(Head); }
      |                                               ^
../llvm-project/llvm/include/llvm/Support/Registry.h:114:25: note: in instantiation of member function 'llvm::Registry<Fortran::frontend::PluginParseTreeAction>::begin' requested here
  114 |       return make_range(begin(), end());
      |                         ^
../llvm-project/flang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:90:34: note: in instantiation of member function 'llvm::Registry<Fortran::frontend::PluginParseTreeAction>::entries' requested here
   90 |          FrontendPluginRegistry::entries()) {
      |                                  ^
../llvm-project/llvm/include/llvm/Support/Registry.h:61:18: note: forward declaration of template entity is here
   61 |     static node *Head;
      |                  ^
../llvm-project/llvm/include/llvm/Support/Registry.h:110:47: note: add an explicit instantiation declaration to suppress this warning if 'llvm::Registry<Fortran::frontend::PluginParseTreeAction>::Head' is explicitly instantiated in another translation unit
  110 |     static iterator begin() { return iterator(Head); }
      |                                               ^
1 error generated.
377.638 [203/2/7028] Building CXX object tools/flang/lib/Frontend/CMakeFiles/flangFrontend.dir/FrontendAction.cpp.o
381.022 [203/1/7029] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaExpr.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/109024