Fix the rececl chain for redeclarations of predefined decls

Predefined decls like 'Protocol' in objc are not loaded from AST files,
so we cannot rely on loading the canonical decl to complete the redecl
chain for redeclarations of these decls.  The broken redecl chain was
non-circular, so looping over redecls() would hang.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@215929 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 05d3bab9a7dc448069af5774abaeb36348c9df3a..3e24145075eec4d682672c43fe73e6aa87c07f36 100644 (file)
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -2019,6 +2019,8 @@ void ASTDeclReader::mergeRedeclarable(Redeclarable<T> *DBase,
   T *D = static_cast<T*>(DBase);
   T *DCanon = D->getCanonicalDecl();
   if (D != DCanon &&
+      // IDs < NUM_PREDEF_DECL_IDS are not loaded from an AST file.
+      Redecl.getFirstID() >= NUM_PREDEF_DECL_IDS &&
       (!Reader.getContext().getLangOpts().Modules ||
        Reader.getOwningModuleFile(DCanon) == Reader.getOwningModuleFile(D))) {
     // All redeclarations between this declaration and its originally-canonical

diff --git a/test/Index/Inputs/declare-objc-predef.h b/test/Index/Inputs/declare-objc-predef.h
new file mode 100644 (file)
index 0000000..6a03c4f
--- /dev/null
+++ b/test/Index/Inputs/declare-objc-predef.h
@@ -0,0 +1,3 @@
+@class Protocol;
+typedef struct objc_class *Class
+@class id;

diff --git a/test/Index/reparse-predef-objc-protocol.m b/test/Index/reparse-predef-objc-protocol.m
new file mode 100644 (file)
index 0000000..fc9d857
--- /dev/null
+++ b/test/Index/reparse-predef-objc-protocol.m
@@ -0,0 +1,9 @@
+// RUN: env CINDEXTEST_EDITING=1 c-index-test -test-load-source-reparse 3 local %s -I %S/Inputs
+#import "declare-objc-predef.h"
+// PR20633
+
+// CHECK: declare-objc-predef.h:1:8: ObjCInterfaceDecl=Protocol:1:8 Extent=[1:1 - 1:16]
+// CHECK: declare-objc-predef.h:1:8: ObjCClassRef=Protocol:1:8 Extent=[1:8 - 1:16]
+// CHECK: declare-objc-predef.h:2:16: StructDecl=objc_class:2:16 Extent=[2:9 - 2:26]
+// CHECK: declare-objc-predef.h:2:28: TypedefDecl=Class:2:28 (Definition) Extent=[2:1 - 2:33]
+// CHECK: declare-objc-predef.h:2:16: TypeRef=struct objc_class:2:16 Extent=[2:16 - 2:26]