1 files changed, 21 insertions, 8 deletions

diff --git a/lib/AST/DeclObjC.cpp b/lib/AST/DeclObjC.cpp
index d2701211beae..60d05f682e6e 100644
--- a/lib/AST/DeclObjC.cpp
+++ b/lib/AST/DeclObjC.cpp
@@ -800,8 +800,7 @@ void ObjCMethodDecl::setParamsAndSelLocs(ASTContext &C,
   if (Params.empty() && SelLocs.empty())
     return;
 
-  static_assert(llvm::AlignOf<ParmVarDecl *>::Alignment >=
-                    llvm::AlignOf<SourceLocation>::Alignment,
+  static_assert(alignof(ParmVarDecl *) >= alignof(SourceLocation),
                 "Alignment not sufficient for SourceLocation");
 
   unsigned Size = sizeof(ParmVarDecl *) * NumParams +
@@ -871,6 +870,12 @@ ObjCMethodDecl *ObjCMethodDecl::getNextRedeclarationImpl() {
     }
   }
 
+  // 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(),
@@ -897,9 +902,13 @@ ObjCMethodDecl *ObjCMethodDecl::getCanonicalDecl() {
         return MD;
   }
 
-  if (isRedeclaration())
-    return cast<ObjCContainerDecl>(CtxD)->getMethod(getSelector(),
-                                                    isInstanceMethod());
+  if (isRedeclaration()) {
+    // It is possible that we have not done deserializing the ObjCMethod yet.
+    ObjCMethodDecl *MD =
+        cast<ObjCContainerDecl>(CtxD)->getMethod(getSelector(),
+                                                 isInstanceMethod());
+    return MD ? MD : this;
+  }
 
   return this;
 }
@@ -1320,8 +1329,12 @@ ObjCTypeParamDecl *ObjCTypeParamDecl::Create(ASTContext &ctx, DeclContext *dc,
                                              IdentifierInfo *name,
                                              SourceLocation colonLoc,
                                              TypeSourceInfo *boundInfo) {
-  return new (ctx, dc) ObjCTypeParamDecl(ctx, dc, variance, varianceLoc, index,
-                                         nameLoc, name, colonLoc, boundInfo);
+  auto *TPDecl =
+    new (ctx, dc) ObjCTypeParamDecl(ctx, dc, variance, varianceLoc, index,
+                                    nameLoc, name, colonLoc, boundInfo);
+  QualType TPType = ctx.getObjCTypeParamType(TPDecl, {});
+  TPDecl->setTypeForDecl(TPType.getTypePtr());
+  return TPDecl;
 }
 
 ObjCTypeParamDecl *ObjCTypeParamDecl::CreateDeserialized(ASTContext &ctx,
@@ -1366,7 +1379,7 @@ ObjCTypeParamList *ObjCTypeParamList::create(
                      SourceLocation rAngleLoc) {
   void *mem =
       ctx.Allocate(totalSizeToAlloc<ObjCTypeParamDecl *>(typeParams.size()),
-                   llvm::alignOf<ObjCTypeParamList>());
+                   alignof(ObjCTypeParamList));
   return new (mem) ObjCTypeParamList(lAngleLoc, typeParams, rAngleLoc);
 }