[Demangle] Add support for D special identifiers

[dblaikie]

Looks good!

[ljmf00]

Just rebased.

llvm/lib/Demangle/DLangDemangle.cpp

const char *Demangler::parseIdentifier(OutputBuffer *Demangled,
 
   // TODO: Parse template instances with a length prefix.
 
   return parseLName(Demangled, Mangled, Len);
 }
 
 const char *Demangler::parseLName(OutputBuffer *Demangled, const char *Mangled,
                                   unsigned long Len) {
+  switch (Len) {
+  case 6:
+    if (strncmp(Mangled, "__initZ", Len + 1) == 0) {
+      // The static initializer for a given symbol.
+      Demangled->prepend("initializer for ");
+      Demangled->setCurrentPosition(Demangled->getCurrentPosition() - 1);
+      Mangled += Len;
+      return Mangled;
+    }
+    if (strncmp(Mangled, "__vtblZ", Len + 1) == 0) {
+      // The vtable symbol for a given class.
+      Demangled->prepend("vtable for ");
+      Demangled->setCurrentPosition(Demangled->getCurrentPosition() - 1);
+      Mangled += Len;
+      return Mangled;
+    }
+    break;
+
+  case 7:
+    if (strncmp(Mangled, "__ClassZ", Len + 1) == 0) {
+      // The classinfo symbol for a given class.
+      Demangled->prepend("ClassInfo for ");
+      Demangled->setCurrentPosition(Demangled->getCurrentPosition() - 1);
+      Mangled += Len;
+      return Mangled;
+    }
+    break;
+
+  case 11:
+    if (strncmp(Mangled, "__InterfaceZ", Len + 1) == 0) {
+      // The interface symbol for a given class.
+      Demangled->prepend("Interface for ");
+      Demangled->setCurrentPosition(Demangled->getCurrentPosition() - 1);
+      Mangled += Len;
+      return Mangled;
+    }
+    break;
+
+  case 12:
+    if (strncmp(Mangled, "__ModuleInfoZ", Len + 1) == 0) {
+      // The ModuleInfo symbol for a given module.
+      Demangled->prepend("ModuleInfo for ");
+      Demangled->setCurrentPosition(Demangled->getCurrentPosition() - 1);
+      Mangled += Len;
+      return Mangled;
+    }
+    break;
+  }
+
   *Demangled << StringView(Mangled, Len);
   Mangled += Len;
 
   return Mangled;
 }
 
 Demangler::Demangler(const char *Mangled) : Str(Mangled) {}
 

llvm/unittests/Demangle/DLangDemangleTest.cpp

INSTANTIATE_TEST_SUITE_P(
     testing::Values(
         std::make_pair("_Dmain", "D main"), std::make_pair(nullptr, nullptr),
         std::make_pair("_Z", nullptr), std::make_pair("_DDD", nullptr),
         std::make_pair("_D88", nullptr),
         std::make_pair("_D8demangleZ", "demangle"),
         std::make_pair("_D8demangle4testZ", "demangle.test"),
         std::make_pair("_D8demangle4test5test2Z", "demangle.test.test2"),
         std::make_pair("_D8demangle4test0Z", "demangle.test"),
-        std::make_pair("_D8demangle4test03fooZ", "demangle.test.foo")));
+        std::make_pair("_D8demangle4test03fooZ", "demangle.test.foo"),
+        std::make_pair("_D8demangle4test6__initZ",
+                       "initializer for demangle.test"),
+        std::make_pair("_D8demangle4test6__vtblZ", "vtable for demangle.test"),
+        std::make_pair("_D8demangle4test7__ClassZ",
+                       "ClassInfo for demangle.test"),
+        std::make_pair("_D8demangle4test11__InterfaceZ",
+                       "Interface for demangle.test"),
+        std::make_pair("_D8demangle4test12__ModuleInfoZ",
+                       "ModuleInfo for demangle.test")));