[Needs review] Fix clang Syntax unit test: add CHKCBindTemporary syntax node

Checked C binds string literals to temporaries. Add CHKCBindTemporaryExpression as a syntax node and add a separate Checked C case for the StringLiteral syntax test that expects a CHKCBindTemporary parent for StringLiteral expressions.

Author: kakje

clang/include/clang/Tooling/Syntax/Nodes.h

@@ -44,6 +44,7 @@ enum class NodeKind : uint16_t {
   PostfixUnaryOperatorExpression,
   BinaryOperatorExpression,
   ParenExpression,
+  CHKCBindTemporaryExpression,
   IntegerLiteralExpression,
   CharacterLiteralExpression,
   FloatingLiteralExpression,
@@ -167,7 +168,8 @@ enum class NodeRole : uint8_t {
   IdExpression_id,
   IdExpression_qualifier,
   NestedNameSpecifier_specifier,
-  ParenExpression_subExpression
+  ParenExpression_subExpression,
+  CHKCBindTemporaryExpression_subExpression
 };
 /// For debugging purposes.
 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, NodeRole R);
@@ -267,6 +269,17 @@ class ParenExpression final : public Expression {
   syntax::Leaf *closeParen();
 };
 
+/// Models binding the result of evaluating an expression
+/// to an anonymous temporary. Checked C-specific.
+class CHKCBindTemporaryExpression final : public Expression {
+public:
+  CHKCBindTemporaryExpression() : Expression(NodeKind::CHKCBindTemporaryExpression) {}
+  static bool classof(const Node *N) {
+    return N->kind() == NodeKind::CHKCBindTemporaryExpression;
+  }
+  syntax::Expression *subExpression();
+};
+
 /// Expression for integer literals. C++ [lex.icon]
 class IntegerLiteralExpression final : public Expression {
 public:

clang/lib/Tooling/Syntax/BuildTree.cpp

@@ -793,6 +793,14 @@ class BuildTreeVisitor : public RecursiveASTVisitor<BuildTreeVisitor> {
     return true;
   }
 
+  bool WalkUpFromCHKCBindTemporaryExpr(CHKCBindTemporaryExpr *S) {
+    Builder.markExprChild(S->getSubExpr(),
+                          syntax::NodeRole::CHKCBindTemporaryExpression_subExpression);
+    Builder.foldNode(Builder.getExprRange(S),
+                     new (allocator()) syntax::CHKCBindTemporaryExpression, S);
+    return true;
+  }
+
   bool WalkUpFromIntegerLiteral(IntegerLiteral *S) {
     Builder.markChildToken(S->getLocation(), syntax::NodeRole::LiteralToken);
     Builder.foldNode(Builder.getExprRange(S),

clang/lib/Tooling/Syntax/Nodes.cpp

@@ -20,6 +20,8 @@ llvm::raw_ostream &syntax::operator<<(llvm::raw_ostream &OS, NodeKind K) {
     return OS << "UnknownExpression";
   case NodeKind::ParenExpression:
     return OS << "ParenExpression";
+  case NodeKind::CHKCBindTemporaryExpression:
+    return OS << "CHKCBindTemporaryExpression";
   case NodeKind::IntegerLiteralExpression:
     return OS << "IntegerLiteralExpression";
   case NodeKind::CharacterLiteralExpression:
@@ -192,6 +194,8 @@ llvm::raw_ostream &syntax::operator<<(llvm::raw_ostream &OS, NodeRole R) {
     return OS << "NestedNameSpecifier_specifier";
   case syntax::NodeRole::ParenExpression_subExpression:
     return OS << "ParenExpression_subExpression";
+  case syntax::NodeRole::CHKCBindTemporaryExpression_subExpression:
+    return OS << "CHKCBindTemporaryExpression_subExpression";
   }
   llvm_unreachable("invalid role");
 }
@@ -230,6 +234,11 @@ syntax::Leaf *syntax::ParenExpression::closeParen() {
       findChild(syntax::NodeRole::CloseParen));
 }
 
+syntax::Expression *syntax::CHKCBindTemporaryExpression::subExpression() {
+  return llvm::cast_or_null<syntax::Expression>(
+      findChild(syntax::NodeRole::CHKCBindTemporaryExpression_subExpression));
+}
+
 syntax::Leaf *syntax::IntegerLiteralExpression::literalToken() {
   return llvm::cast_or_null<syntax::Leaf>(
       findChild(syntax::NodeRole::LiteralToken));

clang/unittests/Tooling/Syntax/TreeTest.cpp

@@ -1669,6 +1669,42 @@ void test() {
 }
 
 TEST_P(SyntaxTreeTest, StringLiteral) {
+  // Checked C wraps each StringLiteral expression in a CHKCBindTemporary
+  // expression. When the test language is C, Checked C is enabled by default.
+  if (!GetParam().isCXX()) {
+    EXPECT_TRUE(treeDumpEqual(
+      R"cpp(
+void test() {
+  "a\n\0\x20";
+  L"αβ";
+}
+)cpp",
+      R"txt(
+*: TranslationUnit
+`-SimpleDeclaration
+  |-void
+  |-SimpleDeclarator
+  | |-test
+  | `-ParametersAndQualifiers
+  |   |-(
+  |   `-)
+  `-CompoundStatement
+    |-{
+    |-ExpressionStatement
+    | |-CHKCBindTemporaryExpression
+    | | `-StringLiteralExpression
+    | |   `-"a\n\0\x20"
+    | `-;
+    |-ExpressionStatement
+    | |-CHKCBindTemporaryExpression
+    | | `-StringLiteralExpression
+    | |   `-L"αβ"
+    | `-;
+    `-}
+)txt"));
+    return;
+  }
+
   EXPECT_TRUE(treeDumpEqual(
       R"cpp(
 void test() {