ZezhengLi created this revision. ZezhengLi added reviewers: ChuanqiXu, rsmith, urnathan. ZezhengLi added a project: clang. ZezhengLi requested review of this revision. Herald added a subscriber: cfe-commits.
An impilt used of module without prebuild path may cause crash. For example: // ./dir1/C.cppm export module C; // ./dir2/B.cppm export module B; import C; // ./A.cpp import B; import C; When we compile A.cpp without the prebuild path of C.pcm, the compiler will crash. clang++ -std=c++20 --precompile -c ./dir1/C.cppm -o dir1/C.pcm clang++ -std=c++20 --precompile -fprebuilt-module-path=./dir2 -c B.cppm -o B.pcm clang++ -std=c++20 -fprebuilt-module-path=./dir2 A.cpp The prebuilt path of module C is cached when import module B, and in the function HeaderSearch::getCachedModuleFileName, the compiler try to get the filename by modulemap without check if modulemap exists,and there is no modulemap in C++ module. Repository: rG LLVM Github Monorepo https://reviews.llvm.org/D119426 Files: clang/lib/Lex/HeaderSearch.cpp clang/test/Modules/implicit-module-with-missing-path.cpp Index: clang/test/Modules/implicit-module-with-missing-path.cpp =================================================================== --- /dev/null +++ clang/test/Modules/implicit-module-with-missing-path.cpp @@ -0,0 +1,12 @@ +// This tests that the compiler wouldn't crash if the module path misses + +// RUN: rm -rf %t +// RUN: mkdir -p %t/subdir +// RUN: echo "export module C;" >> %t/subdir/C.cppm +// RUN: echo -e "export module B;\nimport C;" >> %t/B.cppm +// RUN: %clang_cc1 -std=c++20 -emit-module-interface %t/subdir/C.cppm -o %t/subdir/C.pcm +// RUN: %clang_cc1 -std=c++20 -emit-module-interface -fprebuilt-module-path=%t/subdir %t/B.cppm -o %t/B.pcm +// RUN: %clang_cc1 -std=c++20 -fprebuilt-module-path=%t %s -fsyntax-only -verify + +import B; +import C; // expected-error {{module 'C' is needed but has not been provided, and implicit use of module files is disabled}} \ No newline at end of file Index: clang/lib/Lex/HeaderSearch.cpp =================================================================== --- clang/lib/Lex/HeaderSearch.cpp +++ clang/lib/Lex/HeaderSearch.cpp @@ -172,6 +172,10 @@ std::string HeaderSearch::getCachedModuleFileName(Module *Module) { const FileEntry *ModuleMap = getModuleMap().getModuleMapFileForUniquing(Module); + // The ModuleMap maybe a nullptr, when we load a cached C++ module without + // *.modulemap file. In this case, just return an empty string. + if (ModuleMap == nullptr) + return {}; return getCachedModuleFileName(Module->Name, ModuleMap->getName()); }
Index: clang/test/Modules/implicit-module-with-missing-path.cpp =================================================================== --- /dev/null +++ clang/test/Modules/implicit-module-with-missing-path.cpp @@ -0,0 +1,12 @@ +// This tests that the compiler wouldn't crash if the module path misses + +// RUN: rm -rf %t +// RUN: mkdir -p %t/subdir +// RUN: echo "export module C;" >> %t/subdir/C.cppm +// RUN: echo -e "export module B;\nimport C;" >> %t/B.cppm +// RUN: %clang_cc1 -std=c++20 -emit-module-interface %t/subdir/C.cppm -o %t/subdir/C.pcm +// RUN: %clang_cc1 -std=c++20 -emit-module-interface -fprebuilt-module-path=%t/subdir %t/B.cppm -o %t/B.pcm +// RUN: %clang_cc1 -std=c++20 -fprebuilt-module-path=%t %s -fsyntax-only -verify + +import B; +import C; // expected-error {{module 'C' is needed but has not been provided, and implicit use of module files is disabled}} \ No newline at end of file Index: clang/lib/Lex/HeaderSearch.cpp =================================================================== --- clang/lib/Lex/HeaderSearch.cpp +++ clang/lib/Lex/HeaderSearch.cpp @@ -172,6 +172,10 @@ std::string HeaderSearch::getCachedModuleFileName(Module *Module) { const FileEntry *ModuleMap = getModuleMap().getModuleMapFileForUniquing(Module); + // The ModuleMap maybe a nullptr, when we load a cached C++ module without + // *.modulemap file. In this case, just return an empty string. + if (ModuleMap == nullptr) + return {}; return getCachedModuleFileName(Module->Name, ModuleMap->getName()); }
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