ci: add msan Linux job

MSan is viral, so it is added to Clang only.

Do not add MSan to MacOS job, since it is not supported in that platform.

Author: mizvekov

.github/workflows/ci.yml

@@ -42,7 +42,7 @@ jobs:
           latest-factors: |
             msvc Optimized-Debug
             gcc UBSan Coverage
-            clang UBSan ASan
+            clang UBSan ASan MSan
             apple-clang UBSan ASan
           factors: ''
           runs-on: |
@@ -66,6 +66,7 @@ jobs:
             clang: git build-essential pkg-config python3 curl openjdk-11-jdk pkg-config libncurses-dev libxml2-utils libxml2-dev g++-14=14.2.0-4ubuntu2~24.04
             msvc: ''
           extra-values: |
+            use-libcxx: {{{ msan }}}
             llvm-hash: a1b6e7ff393533a5c4f3bdfd4efe5da106e2de2b
             llvm-build-preset-prefix: {{#if optimized-debug}}debwithopt{{else}}{{{lowercase build-type}}}{{/if}}
             llvm-build-preset-os: {{#if (ieq os 'windows') }}win{{else}}unix{{/if}}
@@ -77,9 +78,10 @@ jobs:
             llvm-archive-extension: {{#if (ieq os 'windows') }}7z{{else}}tar.bz2{{/if}}
             llvm-archive-filename: {{{ llvm-archive-basename }}}.{{{ llvm-archive-extension }}}
             llvm-sanitizer-config: {{#if (and (ne compiler 'clang') (ne compiler 'apple-clang'))}}{{else if ubsan}}Undefined{{else if asan}}Address{{else if msan}}MemoryWithOrigins{{/if}}
+            llvm-use-libcxx: {{#if use-libcxx }}ON{{else}}OFF{{/if}}
             mrdocs-flags: {{#if (and (eq compiler 'gcc') (not asan)) }}-static{{/if}}{{#if (and (eq compiler 'clang') msan) }}-fsanitize-memory-track-origins{{/if}}
             mrdocs-ccflags: {{{ ccflags }}} {{{ mrdocs-flags }}}
-            mrdocs-cxxflags: {{{ cxxflags }}} {{{ mrdocs-flags }}}
+            mrdocs-cxxflags: {{{ cxxflags }}} {{{ mrdocs-flags }}} {{#if use-libcxx }}-stdlib=libc++{{/if}}
             mrdocs-linkflags: {{#if asan }}-fsanitize=address{{/if}}
             mrdocs-package-generators: {{#if (ieq os 'windows') }}7Z ZIP WIX{{else}}TGZ TXZ{{/if}}
             mrdocs-release-package-artifact: release-packages-{{{ lowercase os }}}
@@ -280,6 +282,8 @@ jobs:
           # The LLVM_USE_SANITIZER option doesn't support GCC.
           extra-args: |
             -DLLVM_USE_SANITIZER=${{ matrix.llvm-sanitizer-config }}
+            -DLLVM_OPTIMIZED_TABLEGEN=ON
+            -DLLVM_ENABLE_LIBCXX=${{ matrix.llvm-use-libcxx }}
           cc: ${{ steps.setup-cpp.outputs.cc }}
           cxx: ${{ steps.setup-cpp.outputs.cxx }}
           ccflags: -gz=zstd