Fixes recovering from errors when parsing braced init lists.

Before we would build huge unwrapped lines which take a long time
to optimze.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179168 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/UnwrappedLineParser.cpp

@@ -440,16 +440,36 @@ void UnwrappedLineParser::parseStructuralElement() {
 void UnwrappedLineParser::parseBracedList() {
   nextToken();
 
+  // FIXME: Once we have an expression parser in the UnwrappedLineParser,
+  // replace this by using parseAssigmentExpression() inside.
+  bool StartOfExpression = true;
   do {
+    // FIXME: When we start to support lambdas, we'll want to parse them away
+    // here, otherwise our bail-out scenarios below break. The better solution
+    // might be to just implement a more or less complete expression parser.
     switch (FormatTok.Tok.getKind()) {
     case tok::l_brace:
+      if (!StartOfExpression) {
+        // Probably a missing closing brace. Bail out.
+        addUnwrappedLine();
+        return;
+      }
       parseBracedList();
+      StartOfExpression = false;
       break;
     case tok::r_brace:
       nextToken();
       return;
+    case tok::semi:
+      // Probably a missing closing brace. Bail out.
+      return;
+    case tok::comma:
+      nextToken();
+      StartOfExpression = true;
+      break;
     default:
       nextToken();
+      StartOfExpression = false;
       break;
     }
   } while (!eof());
@@ -462,6 +482,11 @@ void UnwrappedLineParser::parseReturn() {
     switch (FormatTok.Tok.getKind()) {
     case tok::l_brace:
       parseBracedList();
+      if (FormatTok.Tok.isNot(tok::semi)) {
+        // Assume missing ';'.
+        addUnwrappedLine();
+        return;
+      }
       break;
     case tok::l_paren:
       parseParens();

unittests/Format/FormatTest.cpp

@@ -3734,5 +3734,19 @@ TEST_F(FormatTest, DoNotBreakStringLiteralsInEscapeSequence) {
             format("R\"(\\x\\x00)\"\n", getLLVMStyleWithColumns(7)));
 }
 
+TEST_F(FormatTest, DoNotCreateUnreasonableUnwrappedLines) {
+  verifyFormat("void f() {\n"
+               "  return g() {}\n"
+               "  void h() {}");
+  verifyFormat("if (foo)\n"
+               "  return { forgot_closing_brace();\n"
+               "test();");
+  verifyFormat("int a[] = { void forgot_closing_brace()\n"
+               "{\n"
+               "  f();\n"
+               "  g();\n"
+               "}");
+}
+
 } // end namespace tooling
 } // end namespace clang