[clang] [clang][deps] Implement efficient in-process `ModuleCache` (PR #129751)

Tue Mar 18 14:15:30 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-lld-multistage-test` running on `ppc64le-lld-multistage-test` while building `clang` at step 6 "build-stage1-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/168/builds/9869

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

```
Step 6 (build-stage1-unified-tree) failure: build (failure)
...
59.453 [4249/97/2144] Building PPCGenGlobalISel.inc...
59.473 [4249/96/2145] Building AArch64GenMCCodeEmitter.inc...
59.499 [4249/95/2146] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaTemplateInstantiateDecl.cpp.o
59.506 [4249/94/2147] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaType.cpp.o
59.507 [4249/93/2148] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaExprMember.cpp.o
59.528 [4249/92/2149] Building AArch64GenDisassemblerTables.inc...
59.538 [4249/91/2150] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaConcept.cpp.o
59.553 [4249/90/2151] Building ARMGenFastISel.inc...
59.568 [4249/89/2152] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaDecl.cpp.o
59.569 [4249/88/2153] Building CXX object tools/clang/lib/Tooling/DependencyScanning/CMakeFiles/obj.clangDependencyScanning.dir/DependencyScanningService.cpp.o
FAILED: tools/clang/lib/Tooling/DependencyScanning/CMakeFiles/obj.clangDependencyScanning.dir/DependencyScanningService.cpp.o 
ccache /usr/lib64/ccache/c++ -DCLANG_EXPORTS -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/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/build/stage1/tools/clang/lib/Tooling/DependencyScanning -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/lib/Tooling/DependencyScanning -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/build/stage1/tools/clang/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/build/stage1/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -fno-common -Woverloaded-virtual -fno-strict-aliasing -O3 -DNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT tools/clang/lib/Tooling/DependencyScanning/CMakeFiles/obj.clangDependencyScanning.dir/DependencyScanningService.cpp.o -MF tools/clang/lib/Tooling/DependencyScanning/CMakeFiles/obj.clangDependencyScanning.dir/DependencyScanningService.cpp.o.d -o tools/clang/lib/Tooling/DependencyScanning/CMakeFiles/obj.clangDependencyScanning.dir/DependencyScanningService.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/lib/Tooling/DependencyScanning/DependencyScanningService.cpp
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/lib/Tooling/DependencyScanning/DependencyScanningService.cpp:9:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h:117:22: error: declaration of ‘clang::tooling::dependencies::ModuleCacheMutexes clang::tooling::dependencies::DependencyScanningService::ModuleCacheMutexes’ [-fpermissive]
   ModuleCacheMutexes ModuleCacheMutexes;
                      ^~~~~~~~~~~~~~~~~~
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h:13,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/lib/Tooling/DependencyScanning/DependencyScanningService.cpp:9:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/include/clang/Tooling/DependencyScanning/InProcessModuleCache.h:20:8: error: changes meaning of ‘ModuleCacheMutexes’ from ‘struct clang::tooling::dependencies::ModuleCacheMutexes’ [-fpermissive]
 struct ModuleCacheMutexes {
        ^~~~~~~~~~~~~~~~~~
59.569 [4249/87/2154] Building PPCGenInstrInfo.inc...
59.587 [4249/86/2155] Building CXX object tools/clang/lib/AST/CMakeFiles/obj.clangAST.dir/ExprConstant.cpp.o
59.603 [4249/85/2156] Building VEGenDAGISel.inc...
59.605 [4249/84/2157] Building SystemZGenDAGISel.inc...
59.609 [4249/83/2158] Building RISCVTargetParserDef.inc...
59.620 [4249/82/2159] Building PPCGenDAGISel.inc...
59.652 [4249/81/2160] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaExpr.cpp.o
59.653 [4249/80/2161] Building AArch64GenRegisterBank.inc...
59.674 [4249/79/2162] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaRISCV.cpp.o
59.683 [4249/78/2163] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaTemplateInstantiate.cpp.o
59.716 [4249/77/2164] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaSYCL.cpp.o
59.759 [4249/76/2165] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaTemplateDeductionGuide.cpp.o
59.760 [4249/75/2166] Building RISCVGenMCPseudoLowering.inc...
59.762 [4249/74/2167] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaTemplate.cpp.o
59.811 [4249/73/2168] Building ARMGenGlobalISel.inc...
59.868 [4249/72/2169] Building CXX object tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaOpenMP.cpp.o
59.885 [4249/71/2170] Building VEGenInstrInfo.inc...
59.913 [4249/70/2171] Building CXX object tools/clang/lib/Frontend/CMakeFiles/obj.clangFrontend.dir/CompilerInvocation.cpp.o
In file included from /usr/include/c++/8/cassert:44,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include/llvm/ProfileData/InstrProf.h:39,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include/llvm/ProfileData/InstrProfReader.h:21,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/lib/Frontend/CompilerInvocation.cpp:69:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include/llvm/ProfileData/InstrProf.h: In member function ‘llvm::ArrayRef<llvm::InstrProfValueSiteRecord> llvm::InstrProfRecord::getValueSitesForKind(uint32_t) const’:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include/llvm/ProfileData/InstrProf.h:968:23: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
     assert(IPVK_First <= ValueKind && ValueKind <= IPVK_Last &&
            ~~~~~~~~~~~^~~~~~~~~~~~
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include/llvm/ProfileData/InstrProf.h: In member function ‘std::vector<llvm::InstrProfValueSiteRecord>& llvm::InstrProfRecord::getOrCreateValueSitesForKind(uint32_t)’:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include/llvm/ProfileData/InstrProf.h:977:23: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]

```

</details>

https://github.com/llvm/llvm-project/pull/129751