[CodeComplete] only respect LoadExternal hint at namespace/tu scope

[ilya-biryukov]

LGTM

cfe/trunk/include/clang-c/Index.h

enum CXCodeComplete_Flags {
 
   /**
    * \brief Whether to include brief documentation within the set of code
    * completions returned.
    */
   CXCodeComplete_IncludeBriefComments = 0x04,
 
   /**
-   * \brief Whether to speed up completion by omitting some entities which are
-   * defined in the preamble. There's no guarantee any particular entity will
-   * be omitted. This may be useful if the headers are indexed externally.
+   * Whether to speed up completion by omitting top- or namespace-level entities
+   * defined in the preamble. There's no guarantee any particular entity is
+   * omitted. This may be useful if the headers are indexed externally.
    */
   CXCodeComplete_SkipPreamble = 0x08
 };
 
 /**
  * \brief Bits that represent the context under which completion is occurring.
  *
  * The enumerators in this enumeration may be bitwise-OR'd together if multiple

cfe/trunk/include/clang/Sema/CodeCompleteOptions.h

public:
   /// Currently, this only works when completing qualified IDs (i.e.
   /// `Sema::CodeCompleteQualifiedId`).
   /// FIXME: consider supporting more completion cases with this option.
   unsigned IncludeNamespaceLevelDecls : 1;
 
   /// Show brief documentation comments in code completion results.
   unsigned IncludeBriefComments : 1;
 
-  /// Hint whether to load data from the external AST in order to provide
-  /// full results. If false, declarations from the preamble may be omitted.
+  /// Hint whether to load data from the external AST to provide full results.
+  /// If false, namespace-level declarations from the preamble may be omitted.
   unsigned LoadExternal : 1;
 
   CodeCompleteOptions()
       : IncludeMacros(0), IncludeCodePatterns(0), IncludeGlobals(1),
         IncludeNamespaceLevelDecls(1), IncludeBriefComments(0),
         LoadExternal(1) {}
 };
 
 } // namespace clang
 
 #endif
 

cfe/trunk/lib/Sema/SemaLookup.cpp

if (isa<TranslationUnitDecl>(Ctx) &&
     }
 
     return;
   }
 
   if (CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(Ctx))
     Result.getSema().ForceDeclarationOfImplicitMembers(Class);
 
+  // We sometimes skip loading namespace-level results (they tend to be huge).
+  bool Load = LoadExternal ||
+              !(isa<TranslationUnitDecl>(Ctx) || isa<NamespaceDecl>(Ctx));
   // Enumerate all of the results in this context.
   for (DeclContextLookupResult R :
-       LoadExternal ? Ctx->lookups()
-                    : Ctx->noload_lookups(/*PreserveInternalState=*/false)) {
+       Load ? Ctx->lookups()
     for (auto *D : R) {
       if (auto *ND = Result.getAcceptableDecl(D)) {
         Consumer.FoundDecl(ND, Visited.checkHidden(ND), Ctx, InBaseClass);
         Visited.add(ND);
       }
     }
   }
 

cfe/trunk/test/Index/complete-pch-skip.cpp

 namespace ns {
 int bar;
 }
 
 int main() { return ns:: }
+int main2() { return ns::foo(). }
 
-// RUN: echo "namespace ns { int foo; }" > %t.h
+// RUN: echo "namespace ns { struct foo { int baz }; }" > %t.h
 // RUN: c-index-test -write-pch %t.h.pch -x c++-header %t.h
 //
 // RUN: c-index-test -code-completion-at=%s:5:26 -include %t.h %s | FileCheck -check-prefix=WITH-PCH %s
 // WITH-PCH: {TypedText bar}
 // WITH-PCH: {TypedText foo}
 
 // RUN: env CINDEXTEST_COMPLETION_SKIP_PREAMBLE=1 c-index-test -code-completion-at=%s:5:26 -include %t.h %s | FileCheck -check-prefix=SKIP-PCH %s
 // SKIP-PCH-NOT: foo
 // SKIP-PCH: {TypedText bar}
 // SKIP-PCH-NOT: foo
 
 // Verify that with *no* preamble (no -include flag) we still get local results.
 // SkipPreamble used to break this, by making lookup *too* lazy.
 // RUN: env CINDEXTEST_COMPLETION_SKIP_PREAMBLE=1 c-index-test -code-completion-at=%s:5:26 %s | FileCheck -check-prefix=NO-PCH %s
 // NO-PCH-NOT: foo
 // NO-PCH: {TypedText bar}
 // NO-PCH-NOT: foo
 
+// Verify that we still get member results from the preamble.
+// RUN: env CINDEXTEST_COMPLETION_SKIP_PREAMBLE=1 c-index-test -code-completion-at=%s:6:32 -include %t.h %s | FileCheck -check-prefix=MEMBER %s
+// MEMBER: {TypedText baz}
+