Modules: set SystemHeader to true if we are building a system module.

If we are processing a #include from a module build, we should treat it
as a system header if we're building a system module. Passing an optional
flag to HeaderSearch::LookupFile.

Before this, the testing case will crash when accessing a freed FileEntry.

rdar://26214027

llvm-svn: 269730

2 files changed, 10 insertions, 6 deletions

diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 3bb7f8e0428..e627c786407 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -565,7 +565,7 @@ const FileEntry *HeaderSearch::LookupFile(
     ArrayRef<std::pair<const FileEntry *, const DirectoryEntry *>> Includers,
     SmallVectorImpl<char> *SearchPath, SmallVectorImpl<char> *RelativePath,
     Module *RequestingModule, ModuleMap::KnownHeader *SuggestedModule,
-    bool SkipCache) {
+    bool SkipCache, bool BuildSystemModule) {
   if (SuggestedModule)
     *SuggestedModule = ModuleMap::KnownHeader();
     
@@ -613,11 +613,12 @@ const FileEntry *HeaderSearch::LookupFile(
       // getFileAndSuggestModule, because it's a reference to an element of
       // a container that could be reallocated across this call.
       //
-      // FIXME: If we have no includer, that means we're processing a #include
+      // If we have no includer, that means we're processing a #include
       // from a module build. We should treat this as a system header if we're
       // building a [system] module.
       bool IncluderIsSystemHeader =
-          Includer && getFileInfo(Includer).DirInfo != SrcMgr::C_User;
+          (Includer && getFileInfo(Includer).DirInfo != SrcMgr::C_User) ||
+          (!Includer && BuildSystemModule);
       if (const FileEntry *FE = getFileAndSuggestModule(
               TmpDir, IncluderAndDir.second, IncluderIsSystemHeader,
               RequestingModule, SuggestedModule)) {
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index c33f9aba267..34adf7fac29 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -671,6 +671,7 @@ const FileEntry *Preprocessor::LookupFile(
   // stack, record the parent #includes.
   SmallVector<std::pair<const FileEntry *, const DirectoryEntry *>, 16>
       Includers;
+  bool BuildSystemModule = false;
   if (!FromDir && !FromFile) {
     FileID FID = getCurrentFileLexer()->getFileID();
     const FileEntry *FileEnt = SourceMgr.getFileEntryForID(FID);
@@ -688,9 +689,10 @@ const FileEntry *Preprocessor::LookupFile(
     // come from header declarations in the module map) relative to the module
     // map file.
     if (!FileEnt) {
-      if (FID == SourceMgr.getMainFileID() && MainFileDir)
+      if (FID == SourceMgr.getMainFileID() && MainFileDir) {
         Includers.push_back(std::make_pair(nullptr, MainFileDir));
-      else if ((FileEnt =
+        BuildSystemModule = getCurrentModule()->IsSystem;
+      } else if ((FileEnt =
                     SourceMgr.getFileEntryForID(SourceMgr.getMainFileID())))
         Includers.push_back(std::make_pair(FileEnt, FileMgr.getDirectory(".")));
     } else {
@@ -736,7 +738,8 @@ const FileEntry *Preprocessor::LookupFile(
   // Do a standard file entry lookup.
   const FileEntry *FE = HeaderInfo.LookupFile(
       Filename, FilenameLoc, isAngled, FromDir, CurDir, Includers, SearchPath,
-      RelativePath, RequestingModule, SuggestedModule, SkipCache);
+      RelativePath, RequestingModule, SuggestedModule, SkipCache,
+      BuildSystemModule);
   if (FE) {
     if (SuggestedModule && !LangOpts.AsmPreprocessor)
       HeaderInfo.getModuleMap().diagnoseHeaderInclusion(