[PCH] After deserializing a DeclContext, if it has external lexical decls but not

external visible decls, call DeclContext::setMustBuildLookupTable so that the
"lazy decls" bit of the LookupPtr is set.

Previously, in non-C++, if there were no new declarations causing the "lazy decls" bit
to be set, then DeclContext::lookups_begin() would fail to return the decls from the PCH.

Fixes rdar://12316296.

llvm-svn: 164351

clang/lib/Serialization/ASTReader.cpp

@@ -1661,6 +1661,10 @@ ASTReader::ReadASTBlock(ModuleFile &F) {
         return Failure;
       }
 
+      DeclContext *DC = Context.getTranslationUnitDecl();
+      if (!DC->hasExternalVisibleStorage() && DC->hasExternalLexicalStorage())
+        DC->setMustBuildLookupTable();
+
       return Success;
     }
 

clang/lib/Serialization/ASTReaderDecl.cpp

@@ -2127,6 +2127,9 @@ Decl *ASTReader::ReadDeclRecord(DeclID ID) {
       }
       PendingVisibleUpdates.erase(I);
     }
+
+    if (!DC->hasExternalVisibleStorage() && DC->hasExternalLexicalStorage())
+      DC->setMustBuildLookupTable();
   }
   assert(Idx == Record.size());
 

clang/test/Index/rdar12316296-codecompletion.m

@@ -0,0 +1,23 @@
+// RUN: c-index-test -write-pch %t.h.pch %s
+// RUN: c-index-test -code-completion-at=%s:19:1 %s -include %t.h | FileCheck %s
+
+// <rdar://12316296> clang Code Completion returns nothing but preprocessor macros
+
+#ifndef HEADER
+#define HEADER
+
+@interface I
+@end
+
+// CHECK: FunctionDecl:{ResultType void}{TypedText foo}
+void foo();
+
+#else
+
+@implementation I
+-(void)meth {
+
+}
+@end
+
+#endif