[CodeComplete] Add an option to omit results from the preamble.

Summary:
Enumerating the contents of a namespace or global scope will omit any
decls that aren't already loaded, instead of deserializing them from the
PCH.

This allows a fast hybrid code completion where symbols from headers are
provided by an external index. (Sema already exposes the information
needed to do a reasonabl job of filtering them).
Clangd plans to implement this hybrid.

This option is just a hint - callers still need to postfilter results if
they want to *avoid* completing decls outside the main file.

Reviewers: bkramer, ilya-biryukov

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D41989

llvm-svn: 322371

1 files changed, 40 insertions, 23 deletions

diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index 2acc896d53d..f7adaf4dcd0 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -3524,7 +3524,8 @@ void Sema::CodeCompleteOrdinaryName(Scope *S,
   
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
 
   AddOrdinaryNameResults(CompletionContext, S, *this, Results);
   Results.ExitScope();
@@ -3599,7 +3600,8 @@ void Sema::CodeCompleteDeclSpec(Scope *S, DeclSpec &DS,
       Results.setFilter(&ResultBuilder::IsImpossibleToSatisfy);
       CodeCompletionDeclConsumer Consumer(Results, CurContext);
       LookupVisibleDecls(S, LookupNestedNameSpecifierName, Consumer,
-                         CodeCompleter->includeGlobals());
+                         CodeCompleter->includeGlobals(),
+                         CodeCompleter->loadExternal());
       Results.setFilter(nullptr);
     }
   }
@@ -3669,8 +3671,9 @@ void Sema::CodeCompleteExpression(Scope *S,
   
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
-  
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
+
   Results.EnterNewScope();
   AddOrdinaryNameResults(PCC_Expression, S, *this, Results);
   Results.ExitScope();
@@ -3939,7 +3942,8 @@ static void AddRecordMembersCompletionResults(Sema &SemaRef,
   CodeCompletionDeclConsumer Consumer(Results, SemaRef.CurContext);
   SemaRef.LookupVisibleDecls(RD, Sema::LookupMemberName, Consumer,
                              SemaRef.CodeCompleter->includeGlobals(),
-                             /*IncludeDependentBases=*/true);
+                             /*IncludeDependentBases=*/true,
+                             SemaRef.CodeCompleter->loadExternal());
 
   if (SemaRef.getLangOpts().CPlusPlus) {
     if (!Results.empty()) {
@@ -4049,8 +4053,9 @@ void Sema::CodeCompleteMemberReferenceExpr(Scope *S, Expr *Base,
     if (Class) {
       CodeCompletionDeclConsumer Consumer(Results, CurContext);
       Results.setFilter(&ResultBuilder::IsObjCIvar);
-      LookupVisibleDecls(Class, LookupMemberName, Consumer,
-                         CodeCompleter->includeGlobals());
+      LookupVisibleDecls(
+          Class, LookupMemberName, Consumer, CodeCompleter->includeGlobals(),
+          /*IncludeDependentBases=*/false, CodeCompleter->loadExternal());
     }
   }
   
@@ -4124,12 +4129,15 @@ void Sema::CodeCompleteTag(Scope *S, unsigned TagSpec) {
   // First pass: look for tags.
   Results.setFilter(Filter);
   LookupVisibleDecls(S, LookupTagName, Consumer,
-                     CodeCompleter->includeGlobals());
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
 
   if (CodeCompleter->includeGlobals()) {
     // Second pass: look for nested name specifiers.
     Results.setFilter(&ResultBuilder::IsNestedNameSpecifier);
-    LookupVisibleDecls(S, LookupNestedNameSpecifierName, Consumer);
+    LookupVisibleDecls(S, LookupNestedNameSpecifierName, Consumer,
+                       CodeCompleter->includeGlobals(),
+                       CodeCompleter->loadExternal());
   }
   
   HandleCodeCompleteResults(this, CodeCompleter, Results.getCompletionContext(),
@@ -4540,8 +4548,9 @@ void Sema::CodeCompleteAfterIf(Scope *S) {
   
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
-  
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
+
   AddOrdinaryNameResults(PCC_Statement, S, *this, Results);
   
   // "else" block
@@ -4649,7 +4658,8 @@ void Sema::CodeCompleteQualifiedId(Scope *S, CXXScopeSpec &SS,
     CodeCompletionDeclConsumer Consumer(Results, CurContext);
     LookupVisibleDecls(Ctx, LookupOrdinaryName, Consumer,
                        /*IncludeGlobalScope=*/true,
-                       /*IncludeDependentBases=*/true);
+                       /*IncludeDependentBases=*/true,
+                       CodeCompleter->loadExternal());
   }
 
   auto CC = Results.getCompletionContext();
@@ -4677,7 +4687,8 @@ void Sema::CodeCompleteUsing(Scope *S) {
   // nested-name-specifier.
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
   Results.ExitScope();
   
   HandleCodeCompleteResults(this, CodeCompleter, 
@@ -4698,7 +4709,8 @@ void Sema::CodeCompleteUsingDirective(Scope *S) {
   Results.EnterNewScope();
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
   Results.ExitScope();
   HandleCodeCompleteResults(this, CodeCompleter, 
                             CodeCompletionContext::CCC_Namespace,
@@ -4764,7 +4776,8 @@ void Sema::CodeCompleteNamespaceAliasDecl(Scope *S)  {
                         &ResultBuilder::IsNamespaceOrAlias);
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
   HandleCodeCompleteResults(this, CodeCompleter, 
                             Results.getCompletionContext(),
                             Results.data(),Results.size());
@@ -4791,8 +4804,9 @@ void Sema::CodeCompleteOperatorName(Scope *S) {
   Results.allowNestedNameSpecifiers();
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
-  
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
+
   // Add any type specifiers
   AddTypeSpecifierResults(getLangOpts(), Results);
   Results.ExitScope();
@@ -5620,8 +5634,9 @@ void Sema::CodeCompleteObjCPassingType(Scope *S, ObjCDeclSpec &DS,
   Results.setFilter(&ResultBuilder::IsOrdinaryNonValueName);
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
-  
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
+
   if (CodeCompleter->includeMacros())
     AddMacroResults(PP, Results, false);
 
@@ -5834,8 +5849,9 @@ void Sema::CodeCompleteObjCMessageReceiver(Scope *S) {
   CodeCompletionDeclConsumer Consumer(Results, CurContext);
   Results.EnterNewScope();
   LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
-                     CodeCompleter->includeGlobals());
-  
+                     CodeCompleter->includeGlobals(),
+                     CodeCompleter->loadExternal());
+
   // If we are in an Objective-C method inside a class that has a superclass,
   // add "super" as an option.
   if (ObjCMethodDecl *Method = getCurMethodDecl())
@@ -7942,8 +7958,9 @@ void Sema::GatherGlobalCodeCompletions(CodeCompletionAllocator &Allocator,
   if (!CodeCompleter || CodeCompleter->includeGlobals()) {
     CodeCompletionDeclConsumer Consumer(Builder, 
                                         Context.getTranslationUnitDecl());
-    LookupVisibleDecls(Context.getTranslationUnitDecl(), LookupAnyName, 
-                       Consumer);
+    LookupVisibleDecls(Context.getTranslationUnitDecl(), LookupAnyName,
+                       Consumer,
+                       !CodeCompleter || CodeCompleter->loadExternal());
   }
   
   if (!CodeCompleter || CodeCompleter->includeMacros())