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.

2 files changed, 95 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/mangle-ms-auto-templates-memptrs.cpp b/clang/test/CodeGenCXX/mangle-ms-auto-templates-memptrs.cpp
new file mode 100644
index 0000000..360ebde
--- /dev/null
+++ b/clang/test/CodeGenCXX/mangle-ms-auto-templates-memptrs.cpp
@@ -0,0 +1,71 @@
+// RUN: %clang_cc1 -std=c++17 -fms-compatibility-version=19.20 -emit-llvm %s -o - -fms-extensions -fdelayed-template-parsing -triple=x86_64-pc-windows-msvc | FileCheck --check-prefix=AFTER %s
+// RUN: %clang_cc1 -std=c++17 -fms-compatibility-version=19.14 -emit-llvm %s -o - -fms-extensions -fdelayed-template-parsing -triple=x86_64-pc-windows-msvc | FileCheck --check-prefix=BEFORE %s
+
+template <auto a>
+class AutoParmTemplate {
+public:
+    AutoParmTemplate() {}
+};
+
+template <auto a>
+auto AutoFunc() {
+    return a;
+}
+
+struct A {};
+struct B {};
+
+struct S             { int a; void f(); virtual void g(); };
+struct M : A, B      { int a; void f(); virtual void g(); };
+struct V : virtual A { int a; void f(); virtual void g(); };
+
+void template_mangling() {
+
+  AutoParmTemplate<&S::f> auto_method_single_inheritance;
+  // AFTER: call {{.*}} @"??0?$AutoParmTemplate@$MP8S@@EAAXXZ1?f@1@QEAAXXZ@@QEAA@XZ"
+  // BEFORE: call {{.*}} @"??0?$AutoParmTemplate@$1?f@S@@QEAAXXZ@@QEAA@XZ"
+
+  AutoParmTemplate<&M::f> auto_method_multiple_inheritance;
+  // AFTER: call {{.*}} @"??0?$AutoParmTemplate@$MP8M@@EAAXXZH?f@1@QEAAXXZA@@@QEAA@XZ"
+  // BEFORE: call {{.*}} @"??0?$AutoParmTemplate@$H?f@M@@QEAAXXZA@@@QEAA@XZ"
+
+  AutoParmTemplate<&V::f> auto_method_virtual_inheritance;
+  // AFTER: call {{.*}} @"??0?$AutoParmTemplate@$MP8V@@EAAXXZI?f@1@QEAAXXZA@A@@@QEAA@XZ"
+  // BEFORE: call {{.*}} @"??0?$AutoParmTemplate@$I?f@V@@QEAAXXZA@A@@@QEAA@XZ"
+
+  AutoFunc<&S::f>();
+  // AFTER: call {{.*}} @"??$AutoFunc@$MP8S@@EAAXXZ1?f@1@QEAAXXZ@@YA?A?<auto>@@XZ"
+  // BEFORE: call {{.*}} @"??$AutoFunc@$1?f@S@@QEAAXXZ@@YA?A?<auto>@@XZ"
+
+  AutoFunc<&M::f>();
+  // AFTER: call {{.*}} @"??$AutoFunc@$MP8M@@EAAXXZH?f@1@QEAAXXZA@@@YA?A?<auto>@@XZ"
+  // BEFORE: call {{.*}} @"??$AutoFunc@$H?f@M@@QEAAXXZA@@@YA?A?<auto>@@XZ"
+
+  AutoFunc<&V::f>();
+  // AFTER: call {{.*}} @"??$AutoFunc@$MP8V@@EAAXXZI?f@1@QEAAXXZA@A@@@YA?A?<auto>@@XZ"
+  // BEFORE: call {{.*}} @"??$AutoFunc@$I?f@V@@QEAAXXZA@A@@@YA?A?<auto>@@XZ"
+
+  AutoParmTemplate<&S::a> auto_data_single_inheritance;
+  // AFTER: call {{.*}} @"??0?$AutoParmTemplate@$MPEQS@@H07@@QEAA@XZ"
+  // BEFORE: call {{.*}} @"??0?$AutoParmTemplate@$07@@QEAA@XZ"
+
+  AutoParmTemplate<&M::a> auto_data_multiple_inheritance;
+  // AFTER: call {{.*}} @"??0?$AutoParmTemplate@$MPEQM@@H0M@@@QEAA@XZ"
+  // BEFORE: call {{.*}} @"??0?$AutoParmTemplate@$0M@@@QEAA@XZ"
+
+  AutoParmTemplate<&V::a> auto_data_virtual_inheritance;
+  // AFTER: call {{.*}} @"??0?$AutoParmTemplate@$MPEQV@@HFBA@A@@@QEAA@XZ"
+  // BEFORE: call {{.*}} @"??0?$AutoParmTemplate@$FBA@A@@@QEAA@XZ"
+
+  AutoFunc<&S::a>();
+  // AFTER: call {{.*}} @"??$AutoFunc@$MPEQS@@H07@@YA?A?<auto>@@XZ"
+  // BEFORE: call {{.*}} @"??$AutoFunc@$07@@YA?A?<auto>@@XZ"
+
+  AutoFunc<&M::a>();
+  // AFTER: call {{.*}} @"??$AutoFunc@$MPEQM@@H0M@@@YA?A?<auto>@@XZ"
+  // BEFORE: call {{.*}} @"??$AutoFunc@$0M@@@YA?A?<auto>@@XZ"
+
+  AutoFunc<&V::a>();
+  // AFTER: call {{.*}} @"??$AutoFunc@$MPEQV@@HFBA@A@@@YA?A?<auto>@@XZ"
+  // BEFORE: call {{.*}} @"??$AutoFunc@$FBA@A@@@YA?A?<auto>@@XZ"
+}
diff --git a/clang/test/CodeGenCXX/mangle-ms-auto-templates-nullptr.cpp b/clang/test/CodeGenCXX/mangle-ms-auto-templates-nullptr.cpp
new file mode 100644
index 0000000..8f98c1e
--- /dev/null
+++ b/clang/test/CodeGenCXX/mangle-ms-auto-templates-nullptr.cpp
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -std=c++17 -fms-compatibility-version=19.20 -emit-llvm %s -o - -fms-extensions -fdelayed-template-parsing -triple=x86_64-pc-windows-msvc | FileCheck --check-prefix=AFTER %s
+// RUN: %clang_cc1 -std=c++17 -fms-compatibility-version=19.14 -emit-llvm %s -o - -fms-extensions -fdelayed-template-parsing -triple=x86_64-pc-windows-msvc | FileCheck --check-prefix=BEFORE %s
+
+template <auto a>
+class AutoParmTemplate {
+public:
+    AutoParmTemplate() {}
+};
+
+template <auto a>
+auto AutoFunc() {
+    return a;
+}
+
+void template_mangling() {
+
+  AutoParmTemplate<nullptr> auto_nullptr;
+  // AFTER: call {{.*}} @"??0?$AutoParmTemplate@$M$$T0A@@@QEAA@XZ"
+  // BEFORE: call {{.*}} @"??0?$AutoParmTemplate@$0A@@@QEAA@XZ"
+
+  AutoFunc<nullptr>();
+  // AFTER: call {{.*}} @"??$AutoFunc@$M$$T0A@@@YA?A?<auto>@@XZ"
+  // BEFORE: call {{.*}} @"??$AutoFunc@$0A@@@YA?A?<auto>@@XZ"
+}