diff --git a/clang/lib/ARCMigrate/TransProperties.cpp b/clang/lib/ARCMigrate/TransProperties.cpp
--- a/clang/lib/ARCMigrate/TransProperties.cpp
+++ b/clang/lib/ARCMigrate/TransProperties.cpp
@@ -45,7 +45,7 @@
 class PropertiesRewriter {
   MigrationContext &MigrateCtx;
   MigrationPass &Pass;
-  ObjCImplementationDecl *CurImplD;
+  ObjCImplementationDecl *CurImplD = nullptr;
 
   enum PropActionKind {
     PropAction_None,
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -580,7 +580,7 @@
     /// LambdaCaptureFields - Mapping from captured variables/this to
     /// corresponding data members in the closure class.
     llvm::DenseMap<const ValueDecl *, FieldDecl *> LambdaCaptureFields;
-    FieldDecl *LambdaThisCaptureField;
+    FieldDecl *LambdaThisCaptureField = nullptr;
 
     CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
                    const FunctionDecl *Callee, const LValue *This,
diff --git a/clang/lib/Frontend/ASTConsumers.cpp b/clang/lib/Frontend/ASTConsumers.cpp
--- a/clang/lib/Frontend/ASTConsumers.cpp
+++ b/clang/lib/Frontend/ASTConsumers.cpp
@@ -184,7 +184,7 @@
 
 namespace {
   class ASTViewer : public ASTConsumer {
-    ASTContext *Context;
+    ASTContext *Context = nullptr;
   public:
     void Initialize(ASTContext &Context) override {
       this->Context = &Context;
diff --git a/clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp
--- a/clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp
@@ -29,7 +29,7 @@
 class StackAddrEscapeChecker
     : public Checker<check::PreCall, check::PreStmt<ReturnStmt>,
                      check::EndFunction> {
-  mutable IdentifierInfo *dispatch_semaphore_tII;
+  mutable IdentifierInfo *dispatch_semaphore_tII = nullptr;
   mutable std::unique_ptr<BuiltinBug> BT_stackleak;
   mutable std::unique_ptr<BuiltinBug> BT_returnstack;
   mutable std::unique_ptr<BuiltinBug> BT_capturedstackasync;