Fix MSVC 1920+ auto NTTP mangling for pointers to members (#97007)

Fixes https://github.com/llvm/llvm-project/issues/70899.

This is a continuation of
https://github.com/llvm/llvm-project/pull/92477 for pointers to member
data and pointers to member functions.

The mangled name must be prefixed with `$M <mangled-type>` for the
deduced type of the nttp parameter.

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/Demangle/MicrosoftDemangle.cpp b/llvm/lib/Demangle/MicrosoftDemangle.cpp
index e18de9a..c5835e8 100644
--- a/llvm/lib/Demangle/MicrosoftDemangle.cpp
+++ b/llvm/lib/Demangle/MicrosoftDemangle.cpp
@@ -2343,12 +2343,13 @@ Demangler::demangleTemplateParameterList(std::string_view &MangledName) {
       TP.N = TPRN = Arena.alloc<TemplateParameterReferenceNode>();
       TPRN->Symbol = parse(MangledName);
       TPRN->Affinity = PointerAffinity::Reference;
-    } else if (llvm::itanium_demangle::starts_with(MangledName, "$F") ||
-               llvm::itanium_demangle::starts_with(MangledName, "$G")) {
+    } else if (startsWith(MangledName, "$F", "F", !IsAutoNTTP) ||
+               startsWith(MangledName, "$G", "G", !IsAutoNTTP)) {
       TP.N = TPRN = Arena.alloc<TemplateParameterReferenceNode>();
 
       // Data member pointer.
-      MangledName.remove_prefix(1);
+      if (!IsAutoNTTP)
+        MangledName.remove_prefix(1); // Remove leading '$'
       char InheritanceSpecifier = MangledName.front();
       MangledName.remove_prefix(1);