Enter an expression evaluation context when parsing

statement-expressions.  Prevents cleanups and such from being
claimed by the first full-expression in the block.

llvm-svn: 153989

clang/include/clang/Sema/Sema.h

@@ -2802,8 +2802,10 @@ public:
   ExprResult ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
                             LabelDecl *TheDecl);
 
+  void ActOnStartStmtExpr();
   ExprResult ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
                            SourceLocation RPLoc); // "({..})"
+  void ActOnStmtExprError();
 
   // __builtin_offsetof(type, identifier(.identifier|[expr])*)
   struct OffsetOfComponent {

clang/lib/Parse/ParseExpr.cpp

@@ -1917,13 +1917,19 @@ Parser::ParseParenExpression(ParenParseOption &ExprType, bool stopIfCastExpr,
   // unless they've already reported an error.
   if (ExprType >= CompoundStmt && Tok.is(tok::l_brace)) {
     Diag(Tok, diag::ext_gnu_statement_expr);
+
+    Actions.ActOnStartStmtExpr();
+
     ParsedAttributes attrs(AttrFactory);
     StmtResult Stmt(ParseCompoundStatement(attrs, true));
     ExprType = CompoundStmt;
 
     // If the substmt parsed correctly, build the AST node.
-    if (!Stmt.isInvalid())
+    if (!Stmt.isInvalid()) {
       Result = Actions.ActOnStmtExpr(OpenLoc, Stmt.take(), Tok.getLocation());
+    } else {
+      Actions.ActOnStmtExprError();
+    }
   } else if (ExprType >= CompoundLiteral && BridgeCast) {
     tok::TokenKind tokenKind = Tok.getKind();
     SourceLocation BridgeKeywordLoc = ConsumeToken();

clang/lib/Sema/SemaExpr.cpp

@@ -8546,12 +8546,26 @@ static Expr *maybeRebuildARCConsumingStmt(Stmt *Statement) {
   return cleanups;
 }
 
+void Sema::ActOnStartStmtExpr() {
+  PushExpressionEvaluationContext(ExprEvalContexts.back().Context);
+}
+
+void Sema::ActOnStmtExprError() {
+  DiscardCleanupsInEvaluationContext();
+  PopExpressionEvaluationContext();
+}
+
 ExprResult
 Sema::ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
                     SourceLocation RPLoc) { // "({..})"
   assert(SubStmt && isa<CompoundStmt>(SubStmt) && "Invalid action invocation!");
   CompoundStmt *Compound = cast<CompoundStmt>(SubStmt);
 
+  if (hasAnyUnrecoverableErrorsInThisFunction())
+    DiscardCleanupsInEvaluationContext();
+  assert(!ExprNeedsCleanups && "cleanups within StmtExpr not correctly bound!");
+  PopExpressionEvaluationContext();
+
   bool isFileScope
     = (getCurFunctionOrMethodDecl() == 0) && (getCurBlock() == 0);
   if (isFileScope)

clang/test/CodeGenObjC/arc-blocks.m

@@ -514,3 +514,10 @@ void test13(id x) {
 void test14() {
   void (^const x[1])(void) = { ^{} };
 }
+
+// rdar://11149025
+// Don't make invalid ASTs and crash.
+void test15_helper(void (^block)(void), int x);
+void test15(int a) {
+  test15_helper(^{ (void) a; }, ({ a; }));
+}