swift-demangler: Add an option -strip-specialization to get the symbol name of the origin of a specialized function.

Author: eeckstein

include/swift/Demangling/Demangle.h

@@ -221,7 +221,7 @@ class Node {
   // Only to be used by the demangler parsers.
   void addChild(NodePointer Child, NodeFactory &Factory);
   // Only to be used by the demangler parsers.
-  void removeChildAt(unsigned Pos, NodeFactory &factory);
+  void removeChildAt(unsigned Pos);
 
   // Reverses the order of children.
   void reverseChildren(size_t StartingAt = 0);

lib/Demangling/Demangler.cpp

@@ -355,7 +355,7 @@ void Node::addChild(NodePointer Child, NodeFactory &Factory) {
   }
 }
 
-void Node::removeChildAt(unsigned Pos, swift::Demangle::NodeFactory &factory) {
+void Node::removeChildAt(unsigned Pos) {
   switch (NodePayloadKind) {
     case PayloadKind::OneChild:
       assert(Pos == 0);
@@ -1255,7 +1255,7 @@ NodePointer Demangler::popFunctionParamLabels(NodePointer Type) {
       auto Label = getChildIf(Param, Node::Kind::TupleElementName);
 
       if (Label.first) {
-        Param->removeChildAt(Label.second, *this);
+        Param->removeChildAt(Label.second);
         return createNodeWithAllocatedText(Node::Kind::Identifier,
                                            Label.first->getText());
       }

tools/swift-demangle/swift-demangle.cpp

@@ -32,6 +32,8 @@
 
 #include <iostream>
 
+using namespace swift::Demangle;
+
 static llvm::cl::opt<bool>
 ExpandMode("expand",
                llvm::cl::desc("Expand mode (show node structure of the demangling)"));
@@ -44,6 +46,10 @@ static llvm::cl::opt<bool>
 TreeOnly("tree-only",
            llvm::cl::desc("Tree-only mode (do not show the demangled string)"));
 
+static llvm::cl::opt<bool>
+StripSpecialization("strip-specialization",
+           llvm::cl::desc("Remangle the origin of a specialized function"));
+
 static llvm::cl::opt<bool>
 RemangleMode("test-remangle",
            llvm::cl::desc("Remangle test mode (show the remangled string)"));
@@ -82,6 +88,22 @@ static llvm::StringRef substrAfter(llvm::StringRef whole,
   return whole.substr((part.data() - whole.data()) + part.size());
 }
 
+static void stripSpecialization(NodePointer Node) {
+  if (Node->getKind() != Node::Kind::Global)
+    return;
+  switch (Node->getFirstChild()->getKind()) {
+    case Node::Kind::FunctionSignatureSpecialization:
+    case Node::Kind::GenericSpecialization:
+    case Node::Kind::GenericSpecializationNotReAbstracted:
+    case Node::Kind::GenericPartialSpecialization:
+    case Node::Kind::GenericPartialSpecializationNotReAbstracted:
+      Node->removeChildAt(0);
+      break;
+    default:
+      break;
+  }
+}
+
 static void demangle(llvm::raw_ostream &os, llvm::StringRef name,
                      swift::Demangle::Context &DCtx,
                      const swift::Demangle::DemangleOptions &options) {
@@ -142,6 +164,12 @@ static void demangle(llvm::raw_ostream &os, llvm::StringRef name,
       llvm::outs() << remangled;
       return;
     }
+    if (StripSpecialization) {
+      stripSpecialization(pointer);
+      std::string remangled = swift::Demangle::mangleNode(pointer);
+      llvm::outs() << remangled;
+      return;
+    }
     std::string string = swift::Demangle::nodeToString(pointer, options);
     if (!CompactMode)
       llvm::outs() << name << " ---> ";