[ASTDump] Add utility for dumping a label with child nodes

Summary:
Use it to add optional label nodes to Stmt dumps.  This preserves
behavior of InitExprList dump:

// CHECK-NEXT: `-InitListExpr {{.+}} <col:13, col:15> 'U [3]'
// CHECK-NEXT:   |-array_filler: InitListExpr {{.+}} <col:15> 'U' field Field {{.+}} 'i' 'int'
// CHECK-NEXT:   `-InitListExpr {{.+}} <col:14> 'U' field Field {{.+}} 'i' 'int'
// CHECK-NEXT:     `-IntegerLiteral {{.+}} <col:14> 'int' 1

Reviewers: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D55488

llvm-svn: 350957

clang/include/clang/AST/TextNodeDumper.h

@@ -41,6 +41,12 @@ class TextTreeStructure {
 public:
   /// Add a child of the current node.  Calls DoAddChild without arguments
   template <typename Fn> void AddChild(Fn DoAddChild) {
+    return AddChild("", DoAddChild);
+  }
+
+  /// Add a child of the current node with an optional label.
+  /// Calls DoAddChild without arguments.
+  template <typename Fn> void AddChild(StringRef Label, Fn DoAddChild) {
     // If we're at the top level, there's nothing interesting to do; just
     // run the dumper.
     if (TopLevel) {
@@ -56,7 +62,10 @@ public:
       return;
     }
 
-    auto DumpWithIndent = [this, DoAddChild](bool IsLastChild) {
+    // We need to capture an owning-string in the lambda because the lambda
+    // is invoked in a deferred manner.
+    std::string LabelStr = Label;
+    auto DumpWithIndent = [this, DoAddChild, LabelStr](bool IsLastChild) {
       // Print out the appropriate tree structure and work out the prefix for
       // children of this node. For instance:
       //
@@ -73,6 +82,9 @@ public:
         OS << '\n';
         ColorScope Color(OS, ShowColors, IndentColor);
         OS << Prefix << (IsLastChild ? '`' : '|') << '-';
+        if (!LabelStr.empty())
+          OS << LabelStr << ": ";
+
         this->Prefix.push_back(IsLastChild ? ' ' : '|');
         this->Prefix.push_back(' ');
       }

clang/lib/AST/ASTDumper.cpp

@@ -61,6 +61,9 @@ namespace  {
     template<typename Fn> void dumpChild(Fn DoDumpChild) {
       NodeDumper.AddChild(DoDumpChild);
     }
+    template <typename Fn> void dumpChild(StringRef Label, Fn DoDumpChild) {
+      NodeDumper.AddChild(Label, DoDumpChild);
+    }
 
   public:
     ASTDumper(raw_ostream &OS, const CommandTraits *Traits,
@@ -80,7 +83,7 @@ namespace  {
     void setDeserialize(bool D) { Deserialize = D; }
 
     void dumpDecl(const Decl *D);
-    void dumpStmt(const Stmt *S);
+    void dumpStmt(const Stmt *S, StringRef Label = {});
 
     // Utilities
     void dumpType(QualType T) { NodeDumper.dumpType(T); }
@@ -1685,8 +1688,8 @@ void ASTDumper::VisitBlockDecl(const BlockDecl *D) {
 //  Stmt dumping methods.
 //===----------------------------------------------------------------------===//
 
-void ASTDumper::dumpStmt(const Stmt *S) {
-  dumpChild([=] {
+void ASTDumper::dumpStmt(const Stmt *S, StringRef Label) {
+  dumpChild(Label, [=] {
     if (!S) {
       ColorScope Color(OS, ShowColors, NullColor);
       OS << "<<<NULL>>>";
@@ -1957,10 +1960,7 @@ void ASTDumper::VisitInitListExpr(const InitListExpr *ILE) {
     NodeDumper.dumpBareDeclRef(Field);
   }
   if (auto *Filler = ILE->getArrayFiller()) {
-    dumpChild([=] {
-      OS << "array filler";
-      dumpStmt(Filler);
-    });
+    dumpStmt(Filler, "array_filler");
   }
 }
 

clang/test/AST/ast-dump-stmt.cpp

@@ -91,8 +91,7 @@ void TestUnionInitList()
   U us[3] = {1};
 // CHECK: VarDecl {{.+}} <col:3, col:15> col:5 us 'U [3]' cinit
 // CHECK-NEXT: `-InitListExpr {{.+}} <col:13, col:15> 'U [3]'
-// CHECK-NEXT:   |-array filler
-// CHECK-NEXT:   | `-InitListExpr {{.+}} <col:15> 'U' field Field {{.+}} 'i' 'int'
+// CHECK-NEXT:   |-array_filler: InitListExpr {{.+}} <col:15> 'U' field Field {{.+}} 'i' 'int'
 // CHECK-NEXT:   `-InitListExpr {{.+}} <col:14> 'U' field Field {{.+}} 'i' 'int'
 // CHECK-NEXT:     `-IntegerLiteral {{.+}} <col:14> 'int' 1
 }