r287530 - [ObjC] Prevent infinite loops when iterating over redeclaration

[Alex Lorenz via cfe-commits]

Author: arphaman
Date: Mon Nov 21 05:16:30 2016
New Revision: 287530

URL: http://llvm.org/viewvc/llvm-project?rev=287530&view=rev
Log:
[ObjC] Prevent infinite loops when iterating over redeclaration
of a method that was declared in an invalid interface

This commit fixes an infinite loop that occurs when clang tries to iterate over
redeclaration of a method that was declared in an invalid @interface. The
existing validity checks don't catch this as that @interface is a duplicate of
a previously declared valid @interface declaration, so we have to verify that
the found redeclaration is in a valid declaration context.

rdar://29220965

Differential Revision: https://reviews.llvm.org/D26664

Added:
    cfe/trunk/test/SemaObjC/method-redecls-invalid-interface.m
Modified:
    cfe/trunk/lib/AST/DeclObjC.cpp

Modified: cfe/trunk/lib/AST/DeclObjC.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/DeclObjC.cpp?rev=287530&r1=287529&r2=287530&view=diff
==============================================================================
--- cfe/trunk/lib/AST/DeclObjC.cpp (original)
+++ cfe/trunk/lib/AST/DeclObjC.cpp Mon Nov 21 05:16:30 2016
@@ -870,6 +870,12 @@ ObjCMethodDecl *ObjCMethodDecl::getNextR
     }
   }
 
+  // Ensure that the discovered method redeclaration has a valid declaration
+  // context. Used to prevent infinite loops when iterating redeclarations in
+  // a partially invalid AST.
+  if (Redecl && cast<Decl>(Redecl->getDeclContext())->isInvalidDecl())
+    Redecl = nullptr;
+
   if (!Redecl && isRedeclaration()) {
     // This is the last redeclaration, go back to the first method.
     return cast<ObjCContainerDecl>(CtxD)->getMethod(getSelector(),

Added: cfe/trunk/test/SemaObjC/method-redecls-invalid-interface.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/method-redecls-invalid-interface.m?rev=287530&view=auto
==============================================================================
--- cfe/trunk/test/SemaObjC/method-redecls-invalid-interface.m (added)
+++ cfe/trunk/test/SemaObjC/method-redecls-invalid-interface.m Mon Nov 21 05:16:30 2016
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wdocumentation -Wno-objc-root-class %s
+// rdar://29220965
+
+ at interface InvalidInterface { // expected-note {{previous definition is here}}
+  int *_property;
+}
+
+ at end
+
+/*!
+ */
+
+ at interface InvalidInterface // expected-error {{duplicate interface definition for class 'InvalidInterface'}}
+ at property int *property;
+
+-(void) method;
+ at end
+
+ at implementation InvalidInterface
+-(void) method { }
+ at end