From: Ben Langmuir <blangmuir@apple.com>
Date: Mon, 18 Aug 2014 19:32:45 +0000 (+0000)
Subject: Fix the rececl chain for redeclarations of predefined decls
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6dc4e613eb8c3da6f1b83e4b121560ce7f197698;p=clang

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 05d3bab9a7..3e24145075 100644
--- 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
index 0000000000..6a03c4f88d
--- /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
index 0000000000..fc9d8572e0
--- /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]