[PATCH] D48367: [modules] Fix 37878; Autoload subdirectory modulemaps with specific LangOpts

[Yuka Takahashi via Phabricator via cfe-commits]

yamaguchi created this revision.
yamaguchi added reviewers: rsmith, aprantl, bruno.

Reproducer and errors:
https://bugs.llvm.org/show_bug.cgi?id=37878

lookupModule was falling back to loadSubdirectoryModuleMaps when it couldn't
find ModuleName in (proper) search paths. This was causing iteration over all
files in the search path subdirectories for example "/usr/include/foobar" in
bugzilla case.

Users don't expect Clang to load modulemaps in subdirectories implicitly, and
also the disk access is not cheap.

if (ModMap.getLangOpts().ObjC1) is because I heard that this
subdirectory autoloading was supposed to happen only with ObjC.


https://reviews.llvm.org/D48367

Files:
  clang/include/clang/Lex/ModuleMap.h
  clang/lib/Lex/HeaderSearch.cpp


Index: clang/lib/Lex/HeaderSearch.cpp
===================================================================
--- clang/lib/Lex/HeaderSearch.cpp
+++ clang/lib/Lex/HeaderSearch.cpp
@@ -282,7 +282,8 @@
 
     // Load all module maps in the immediate subdirectories of this search
     // directory.
-    loadSubdirectoryModuleMaps(SearchDirs[Idx]);
+    if (ModMap.getLangOpts().ObjC1)
+      loadSubdirectoryModuleMaps(SearchDirs[Idx]);
 
     // Look again for the module.
     Module = ModMap.findModule(ModuleName);
Index: clang/include/clang/Lex/ModuleMap.h
===================================================================
--- clang/include/clang/Lex/ModuleMap.h
+++ clang/include/clang/Lex/ModuleMap.h
@@ -110,6 +110,10 @@
   llvm::StringMap<llvm::StringSet<>> PendingLinkAsModule;
 
 public:
+  const LangOptions getLangOpts() {
+    return LangOpts;
+  }
+
   /// Use PendingLinkAsModule information to mark top level link names that
   /// are going to be replaced by export_as aliases.
   void resolveLinkAsDependencies(Module *Mod);


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