create a separate API to avoid access to a string that has been moved

Author: charles-zablit

include/swift/Demangling/Demangle.h

@@ -484,17 +484,27 @@ class Context {
   /// The lifetime of the returned node tree ends with the lifetime of the
   /// context or with a call of clear().
   NodePointer demangleTypeAsNode(llvm::StringRef MangledName);
-  
+
   /// Demangle the given symbol and return the readable name.
   ///
   /// \param MangledName The mangled symbol string, which start a mangling
   /// prefix: _T, _T0, $S, _$S.
+  /// \param Options The DemangleOptions that will be used by the NodePrinter.
   ///
   /// \returns The demangled string.
   std::string
   demangleSymbolAsString(llvm::StringRef MangledName,
-                         const DemangleOptions &Options = DemangleOptions(),
-                         NodePrinter *printer = nullptr);
+                         const DemangleOptions &Options = DemangleOptions());
+
+  /// Demangle the given symbol.
+  ///
+  /// \param MangledName The mangled symbol string, which start a mangling
+  /// prefix: _T, _T0, $S, _$S.
+  /// \param printer The NodePrinter that will be used to demangle the symbol.
+  ///
+  /// \returns The demangled string.
+  void demangleSymbolAsString(llvm::StringRef MangledName,
+                              NodePrinter *printer);
 
   /// Demangle the given type and return the readable name.
   ///
@@ -551,8 +561,19 @@ class Context {
 /// \returns The demangled string.
 std::string
 demangleSymbolAsString(const char *mangledName, size_t mangledNameLength,
-                       const DemangleOptions &options = DemangleOptions(),
-                       NodePrinter *printer = nullptr);
+                       const DemangleOptions &options = DemangleOptions());
+
+/// Standalone utility function to demangle the given symbol as string.
+///
+/// If performance is an issue when demangling multiple symbols,
+/// Context::demangleSymbolAsString should be used instead.
+/// \param mangledName The mangled name string pointer.
+/// \param mangledNameLength The length of the mangledName string.
+/// \param printer The NodePrinter that will be used to demangle the symbol.
+///
+/// \returns The demangled string.
+void demangleSymbolAsString(const char *mangledName, size_t mangledNameLength,
+                            NodePrinter *printer);
 
 /// Standalone utility function to demangle the given symbol as string.
 ///
@@ -562,10 +583,9 @@ demangleSymbolAsString(const char *mangledName, size_t mangledNameLength,
 /// \returns The demangled string.
 inline std::string
 demangleSymbolAsString(const std::string &mangledName,
-                       const DemangleOptions &options = DemangleOptions(),
-                       NodePrinter *printer = nullptr) {
-  return demangleSymbolAsString(mangledName.data(), mangledName.size(), options,
-                                printer);
+                       const DemangleOptions &options = DemangleOptions()) {
+  return demangleSymbolAsString(mangledName.data(), mangledName.size(),
+                                options);
 }
 
 /// Standalone utility function to demangle the given symbol as string.
@@ -576,10 +596,21 @@ demangleSymbolAsString(const std::string &mangledName,
 /// \returns The demangled string.
 inline std::string
 demangleSymbolAsString(llvm::StringRef MangledName,
-                       const DemangleOptions &Options = DemangleOptions(),
-                       NodePrinter *printer = nullptr) {
-  return demangleSymbolAsString(MangledName.data(), MangledName.size(), Options,
-                                printer);
+                       const DemangleOptions &Options = DemangleOptions()) {
+  return demangleSymbolAsString(MangledName.data(), MangledName.size(),
+                                Options);
+}
+
+/// Standalone utility function to demangle the given symbol as string.
+///
+/// If performance is an issue when demangling multiple symbols,
+/// Context::demangleSymbolAsString should be used instead.
+/// \param MangledName The mangled name string.
+///
+/// \returns The demangled string.
+inline void demangleSymbolAsString(llvm::StringRef MangledName,
+                                   NodePrinter *printer) {
+  demangleSymbolAsString(MangledName.data(), MangledName.size(), printer);
 }
 
 /// Standalone utility function to demangle the given type as string.
@@ -753,8 +784,16 @@ ManglingErrorOr<const char *> mangleNodeAsObjcCString(NodePointer node,
 /// \returns A string representing the demangled name.
 ///
 std::string nodeToString(NodePointer Root,
-                         const DemangleOptions &Options = DemangleOptions(),
-                         NodePrinter *printer = nullptr);
+                         const DemangleOptions &Options = DemangleOptions());
+
+/// Transform the node structure to a string.
+///
+/// \endcode
+///
+/// \param Root A pointer to a parse tree generated by the demangler.
+/// \param Printer A NodePrinter used to pretty print the demangled Node.
+///
+void nodeToString(NodePointer Root, NodePrinter *Printer);
 
 /// Transforms a mangled key path accessor thunk helper
 /// into the identfier/subscript that would be used to invoke it in swift code.
@@ -865,9 +904,12 @@ class NodePrinter {
 
   virtual ~NodePrinter() {}
 
-  std::string printRoot(NodePointer root) {
+  void printRoot(NodePointer root) {
     isValid = true;
     print(root, 0);
+  }
+
+  std::string takeString() {
     if (isValid)
       return std::move(Printer).str();
     return "";

lib/Demangling/Context.cpp

@@ -56,17 +56,22 @@ NodePointer Context::demangleTypeAsNode(llvm::StringRef MangledName) {
 #if SWIFT_STDLIB_HAS_TYPE_PRINTING
 
 std::string Context::demangleSymbolAsString(llvm::StringRef MangledName,
-                                            const DemangleOptions &Options,
-                                            NodePrinter *printer) {
+                                            const DemangleOptions &Options) {
   NodePointer root = demangleSymbolAsNode(MangledName);
   if (!root) return MangledName.str();
 
-  std::string demangling = nodeToString(root, Options, printer);
+  std::string demangling = nodeToString(root, Options);
   if (demangling.empty())
     return MangledName.str();
   return demangling;
 }
 
+void Context::demangleSymbolAsString(llvm::StringRef MangledName,
+                                     NodePrinter *printer) {
+  NodePointer root = demangleSymbolAsNode(MangledName);
+  nodeToString(root, printer);
+}
+
 std::string Context::demangleTypeAsString(llvm::StringRef MangledName,
                                           const DemangleOptions &Options) {
   NodePointer root = demangleTypeAsNode(MangledName);
@@ -270,11 +275,17 @@ std::string Context::getModuleName(llvm::StringRef mangledName) {
 
 std::string demangleSymbolAsString(const char *MangledName,
                                    size_t MangledNameLength,
-                                   const DemangleOptions &Options,
-                                   NodePrinter *printer) {
+                                   const DemangleOptions &Options) {
+  Context Ctx;
+  return Ctx.demangleSymbolAsString(StringRef(MangledName, MangledNameLength),
+                                    Options);
+}
+
+void demangleSymbolAsString(const char *MangledName, size_t MangledNameLength,
+                            NodePrinter *printer) {
   Context Ctx;
   return Ctx.demangleSymbolAsString(StringRef(MangledName, MangledNameLength),
-                                    Options, printer);
+                                    printer);
 }
 
 std::string demangleTypeAsString(const char *MangledName,

lib/Demangling/NodePrinter.cpp

@@ -3747,15 +3747,18 @@ std::string Demangle::keyPathSourceString(const char *MangledName,
 }
 
 std::string Demangle::nodeToString(NodePointer root,
-                                   const DemangleOptions &options,
-                                   NodePrinter *printer) {
+                                   const DemangleOptions &options) {
   if (!root)
     return "";
+  NodePrinter printer = NodePrinter(options);
+  nodeToString(root, &printer);
+  return printer.takeString();
+}
 
-  if (printer) {
-    return printer->printRoot(root);
-  }
-  return NodePrinter(options).printRoot(root);
+void Demangle::nodeToString(NodePointer root, NodePrinter *printer) {
+  if (!root)
+    return;
+  printer->printRoot(root);
 }
 
 #endif