[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, 1 insertions, 0 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 1160df15a92..74abbf3b725 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -2068,6 +2068,7 @@ void ASTUnit::CodeComplete(
   CodeCompleteOpts.IncludeCodePatterns = IncludeCodePatterns;
   CodeCompleteOpts.IncludeGlobals = CachedCompletionResults.empty();
   CodeCompleteOpts.IncludeBriefComments = IncludeBriefComments;
+  CodeCompleteOpts.LoadExternal = Consumer.loadExternal();
 
   assert(IncludeBriefComments == this->IncludeBriefCommentsInCodeCompletion);