[clangd] Report position of opening paren in singature help

Summary: Only accessible via the C++ API at the moment.

Reviewers: sammccall

Reviewed By: sammccall

Subscribers: ioeric, MaskRay, jkorous, arphaman, kadircet, cfe-commits

Differential Revision: https://reviews.llvm.org/D51437

llvm-svn: 341065

1 files changed, 11 insertions, 1 deletions

diff --git a/clang-tools-extra/clangd/CodeComplete.cpp b/clang-tools-extra/clangd/CodeComplete.cpp
index 65c415fbaca..e355a83328d 100644
--- a/clang-tools-extra/clangd/CodeComplete.cpp
+++ b/clang-tools-extra/clangd/CodeComplete.cpp
@@ -794,7 +794,17 @@ public:
 
   void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
                                  OverloadCandidate *Candidates,
-                                 unsigned NumCandidates) override {
+                                 unsigned NumCandidates,
+                                 SourceLocation OpenParLoc) override {
+    assert(!OpenParLoc.isInvalid());
+    SourceManager &SrcMgr = S.getSourceManager();
+    OpenParLoc = SrcMgr.getFileLoc(OpenParLoc);
+    if (SrcMgr.isInMainFile(OpenParLoc))
+      SigHelp.argListStart = sourceLocToPosition(SrcMgr, OpenParLoc);
+    else
+      elog("Location oustide main file in signature help: {0}",
+           OpenParLoc.printToString(SrcMgr));
+
     std::vector<ScoredSignature> ScoredSignatures;
     SigHelp.signatures.reserve(NumCandidates);
     ScoredSignatures.reserve(NumCandidates);