From e28e95684407dd9c02a7f2252c7020d4a433ddae Mon Sep 17 00:00:00 2001
From: Argyrios Kyrtzidis <akyrtzi@gmail.com>
Date: Wed, 9 Mar 2016 02:12:46 +0000
Subject: [PATCH] [index] libclang: Make sure to treat forward ObjC protocols
 as ObjCProtocolRef declarations, and fix related crash.

rdar://25035376

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@262985 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Index/IndexDecl.cpp                | 8 ++++----
 test/Index/index-refs.m                | 5 +++++
 tools/libclang/CXIndexDataConsumer.cpp | 8 ++++++++
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/lib/Index/IndexDecl.cpp b/lib/Index/IndexDecl.cpp
index af438f3684..5f5c49a2e3 100644
--- a/lib/Index/IndexDecl.cpp
+++ b/lib/Index/IndexDecl.cpp
@@ -227,8 +227,8 @@ public:
       TRY_TO(handleReferencedProtocols(D->getReferencedProtocols(), D));
       TRY_TO(IndexCtx.indexDeclContext(D));
     } else {
-      return IndexCtx.handleReference(D, D->getLocation(), nullptr, nullptr,
-                                      SymbolRoleSet());
+      return IndexCtx.handleReference(D, D->getLocation(), nullptr,
+                                      D->getDeclContext(), SymbolRoleSet());
     }
     return true;
   }
@@ -239,8 +239,8 @@ public:
       TRY_TO(handleReferencedProtocols(D->getReferencedProtocols(), D));
       TRY_TO(IndexCtx.indexDeclContext(D));
     } else {
-      return IndexCtx.handleReference(D, D->getLocation(), nullptr, nullptr,
-                                      SymbolRoleSet());
+      return IndexCtx.handleReference(D, D->getLocation(), nullptr,
+                                      D->getDeclContext(), SymbolRoleSet());
     }
     return true;
   }
diff --git a/test/Index/index-refs.m b/test/Index/index-refs.m
index f25013b882..457712bcbc 100644
--- a/test/Index/index-refs.m
+++ b/test/Index/index-refs.m
@@ -21,7 +21,12 @@ void foo2() {
   [I clsMeth];
 }
 
+@protocol ForwardProt;
+
 // RUN: c-index-test -index-file %s | FileCheck %s
 // CHECK: [indexEntityReference]: kind: objc-protocol | name: Prot | {{.*}} | loc: 12:27
 // CHECK: [indexEntityReference]: kind: struct | name: FooS | {{.*}} | loc: 13:18
 // CHECK: [indexEntityReference]: kind: objc-class | name: I | {{.*}} | loc: 21:4
+
+// CHECK: [indexDeclaration]: kind: objc-protocol | name: ForwardProt | {{.*}} | loc: 24:11
+// CHECK-NEXT: <ObjCContainerInfo>: kind: forward-ref
diff --git a/tools/libclang/CXIndexDataConsumer.cpp b/tools/libclang/CXIndexDataConsumer.cpp
index 322725ec65..4f89e43fd7 100644
--- a/tools/libclang/CXIndexDataConsumer.cpp
+++ b/tools/libclang/CXIndexDataConsumer.cpp
@@ -171,6 +171,14 @@ bool CXIndexDataConsumer::handleDeclOccurence(const Decl *D,
         return true;
       }
     }
+    if (auto *ObjCPD = dyn_cast_or_null<ObjCProtocolDecl>(ASTNode.OrigD)) {
+      if (!ObjCPD->isThisDeclarationADefinition() &&
+          ObjCPD->getLocation() == Loc) {
+        // The libclang API treats this as ObjCProtocolRef declaration.
+        IndexingDeclVisitor(*this, Loc, nullptr).Visit(ObjCPD);
+        return true;
+      }
+    }
 
     CXIdxEntityRefKind Kind = CXIdxEntityRef_Direct;
     if (Roles & (unsigned)SymbolRole::Implicit) {
-- 
2.40.0