https://github.com/AnthonyLatsis updated https://github.com/llvm/llvm-project/pull/154455
>From ef9764a255c47b2cc8fac486193b563d7fd6925b Mon Sep 17 00:00:00 2001 From: Ben Barham <ben_bar...@apple.com> Date: Tue, 1 Jul 2025 18:06:27 -0700 Subject: [PATCH] [clang] Frontend: Destroy compiling compiler instance before read Upstreams https://github.com/swiftlang/llvm-project/pull/10943. https://github.com/llvm/llvm-project/pull/134887 added a clone for the compiler instance in `compileModuleAndReadASTImpl`, which would then be destroyed *after* the corresponding read in the importing instance. Swift has a `SwiftNameLookupExtension` module extension which updates (effectively) global state - populating the lookup table for a module on read and removing it when the module is destroyed. With newly cloned instance, we would then see: - Module compiled with cloned instance - Module read with importing instance - Lookup table for that module added - Cloned instance destroyed - Module from that cloned instance destroyed - Lookup table for that module name removed Depending on the original semantics is incredibly fragile, but for now it's good enough to ensure that the read in the importing instance is after the cloned instanced is destroyed. Ideally we'd only ever add to the lookup tables in the original importing instance, never its clones. --- clang/lib/Frontend/CompilerInstance.cpp | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp index 9f99edadbb70f..28f65b7f8912f 100644 --- a/clang/lib/Frontend/CompilerInstance.cpp +++ b/clang/lib/Frontend/CompilerInstance.cpp @@ -1473,16 +1473,18 @@ static bool compileModuleAndReadASTImpl(CompilerInstance &ImportingInstance, SourceLocation ModuleNameLoc, Module *Module, StringRef ModuleFileName) { - auto Instance = ImportingInstance.cloneForModuleCompile(ModuleNameLoc, Module, - ModuleFileName); - - if (!ImportingInstance.compileModule(ModuleNameLoc, - Module->getTopLevelModuleName(), - ModuleFileName, *Instance)) { - ImportingInstance.getDiagnostics().Report(ModuleNameLoc, - diag::err_module_not_built) - << Module->Name << SourceRange(ImportLoc, ModuleNameLoc); - return false; + { + auto Instance = ImportingInstance.cloneForModuleCompile(ModuleNameLoc, Module, + ModuleFileName); + + if (!ImportingInstance.compileModule(ModuleNameLoc, + Module->getTopLevelModuleName(), + ModuleFileName, *Instance)) { + ImportingInstance.getDiagnostics().Report(ModuleNameLoc, + diag::err_module_not_built) + << Module->Name << SourceRange(ImportLoc, ModuleNameLoc); + return false; + } } // The module is built successfully, we can update its timestamp now. _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
