r214932 - MS ABI: Mangle empty type parameter packs compatibly

[David Majnemer]

Author: majnemer
Date: Tue Aug  5 17:43:45 2014
New Revision: 214932

URL: http://llvm.org/viewvc/llvm-project?rev=214932&view=rev
Log:
MS ABI: Mangle empty type parameter packs compatibly

The MS mangling scheme apparently has separate manglings for type and
non-type parameter packs when they are empty.  Match template arguments
with parameters during mangling; check the parameter to see if it was
destined to hold type-ish things or nontype-ish things.

Differential Revision: http://reviews.llvm.org/D4792

Modified:
    cfe/trunk/lib/AST/MicrosoftMangle.cpp
    cfe/trunk/test/CodeGenCXX/mangle-ms-cxx11.cpp

Modified: cfe/trunk/lib/AST/MicrosoftMangle.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/MicrosoftMangle.cpp?rev=214932&r1=214931&r2=214932&view=diff
==============================================================================
--- cfe/trunk/lib/AST/MicrosoftMangle.cpp (original)
+++ cfe/trunk/lib/AST/MicrosoftMangle.cpp Tue Aug  5 17:43:45 2014
@@ -279,7 +279,8 @@ private:
 
   void mangleTemplateArgs(const TemplateDecl *TD,
                           const TemplateArgumentList &TemplateArgs);
-  void mangleTemplateArg(const TemplateDecl *TD, const TemplateArgument &TA);
+  void mangleTemplateArg(const TemplateDecl *TD, const TemplateArgument &TA,
+                         const NamedDecl *Parm);
 };
 }
 
@@ -1104,12 +1105,18 @@ void MicrosoftCXXNameMangler::mangleExpr
 void MicrosoftCXXNameMangler::mangleTemplateArgs(
     const TemplateDecl *TD, const TemplateArgumentList &TemplateArgs) {
   // <template-args> ::= <template-arg>+
+  const TemplateParameterList *TPL = TD->getTemplateParameters();
+  assert(TPL->size() == TemplateArgs.size() &&
+         "size mismatch between args and parms!");
+
+  unsigned Idx = 0;
   for (const TemplateArgument &TA : TemplateArgs.asArray())
-    mangleTemplateArg(TD, TA);
+    mangleTemplateArg(TD, TA, TPL->getParam(Idx++));
 }
 
 void MicrosoftCXXNameMangler::mangleTemplateArg(const TemplateDecl *TD,
-                                                const TemplateArgument &TA) {
+                                                const TemplateArgument &TA,
+                                                const NamedDecl *Parm) {
   // <template-arg> ::= <type>
   //                ::= <integer-literal>
   //                ::= <member-data-pointer>
@@ -1172,10 +1179,16 @@ void MicrosoftCXXNameMangler::mangleTemp
   case TemplateArgument::Pack: {
     ArrayRef<TemplateArgument> TemplateArgs = TA.getPackAsArray();
     if (TemplateArgs.empty()) {
-      Out << "$S";
+      if (isa<TemplateTypeParmDecl>(Parm) ||
+          isa<TemplateTemplateParmDecl>(Parm))
+        Out << "$$V";
+      else if (isa<NonTypeTemplateParmDecl>(Parm))
+        Out << "$S";
+      else
+        llvm_unreachable("unexpected template parameter decl!");
     } else {
       for (const TemplateArgument &PA : TemplateArgs)
-        mangleTemplateArg(TD, PA);
+        mangleTemplateArg(TD, PA, Parm);
     }
     break;
   }

Modified: cfe/trunk/test/CodeGenCXX/mangle-ms-cxx11.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/mangle-ms-cxx11.cpp?rev=214932&r1=214931&r2=214932&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/mangle-ms-cxx11.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/mangle-ms-cxx11.cpp Tue Aug  5 17:43:45 2014
@@ -140,6 +140,18 @@ void templ_fun_with_pack() {}
 template void templ_fun_with_pack<>();
 // CHECK-DAG: @"\01??$templ_fun_with_pack@$S@@YAXXZ"
 
+template <typename...>
+void templ_fun_with_ty_pack() {}
+
+template void templ_fun_with_ty_pack<>();
+// CHECK-DAG: @"\01??$templ_fun_with_ty_pack@$$V@@YAXXZ"
+
+template <template <class> class...>
+void templ_fun_with_templ_templ_pack() {}
+
+template void templ_fun_with_templ_templ_pack<>();
+// CHECK-DAG: @"\01??$templ_fun_with_templ_templ_pack@$$V@@YAXXZ"
+
 namespace PR20047 {
 template <typename T>
 struct A {};