Fix the AST representation for non-type template arguments to encode

enough information so we can mangle them correctly in cases involving
dependent parameter types. (This specifically impacts cases involving
null pointers and cases involving parameters of reference type.)
Fix the mangler to use this information instead of trying to scavenge
it out of the parameter declaration.

<rdar://problem/12296776>.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164656 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 42 insertions, 46 deletions

diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index bc40cbb8c9..0efe710acc 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -2843,6 +2843,7 @@ bool Sema::CheckTemplateArgument(NamedDecl *Param,
 
     case TemplateArgument::Declaration:
     case TemplateArgument::Integral:
+    case TemplateArgument::NullPtr:
       // We've already checked this template argument, so just copy
       // it to the list of converted arguments.
       Converted.push_back(Arg.getArgument());
@@ -2977,6 +2978,8 @@ bool Sema::CheckTemplateArgument(NamedDecl *Param,
     llvm_unreachable("Declaration argument with template template parameter");
   case TemplateArgument::Integral:
     llvm_unreachable("Integral argument with template template parameter");
+  case TemplateArgument::NullPtr:
+    llvm_unreachable("Null pointer argument with template template parameter");
 
   case TemplateArgument::Pack:
     llvm_unreachable("Caller must expand template argument packs");
@@ -3068,15 +3071,12 @@ bool Sema::CheckTemplateArgumentList(TemplateDecl *Template,
       if (*Expansions == ArgumentPack.size()) {
         // We're done with this parameter pack. Pack up its arguments and add
         // them to the list.
-        if (ArgumentPack.empty())
-          Converted.push_back(TemplateArgument(0, 0));
-        else {
-          Converted.push_back(
-            TemplateArgument::CreatePackCopy(Context,
-                                             ArgumentPack.data(),
-                                             ArgumentPack.size()));
-          ArgumentPack.clear();
-        }
+        Converted.push_back(
+          TemplateArgument::CreatePackCopy(Context,
+                                           ArgumentPack.data(),
+                                           ArgumentPack.size()));
+        ArgumentPack.clear();
+
         // This argument is assigned to the next parameter.
         ++Param;
         continue;
@@ -3143,15 +3143,11 @@ bool Sema::CheckTemplateArgumentList(TemplateDecl *Template,
 
         // Push the argument pack onto the list of converted arguments.
         if (InFinalParameterPack) {
-          if (ArgumentPack.empty())
-            Converted.push_back(TemplateArgument(0, 0));
-          else {
-            Converted.push_back(
-              TemplateArgument::CreatePackCopy(Context,
-                                               ArgumentPack.data(),
-                                               ArgumentPack.size()));
-            ArgumentPack.clear();
-          }
+          Converted.push_back(
+            TemplateArgument::CreatePackCopy(Context,
+                                             ArgumentPack.data(),
+                                             ArgumentPack.size()));
+          ArgumentPack.clear();
         } else if (ExpansionIntoFixedList) {
           // We have expanded a pack into a fixed list.
           *ExpansionIntoFixedList = true;
@@ -3185,14 +3181,10 @@ bool Sema::CheckTemplateArgumentList(TemplateDecl *Template,
       if (Param + 1 != ParamEnd)
         return true;
 
-      if (ArgumentPack.empty())
-        Converted.push_back(TemplateArgument(0, 0));
-      else {
-        Converted.push_back(TemplateArgument::CreatePackCopy(Context,
-                                                         ArgumentPack.data(),
-                                                         ArgumentPack.size()));
-        ArgumentPack.clear();
-      }
+      Converted.push_back(TemplateArgument::CreatePackCopy(Context,
+                                                       ArgumentPack.data(),
+                                                       ArgumentPack.size()));
+      ArgumentPack.clear();
 
       ++Param;
       continue;
@@ -3679,7 +3671,7 @@ CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
     switch (isNullPointerValueTemplateArgument(S, Param, ParamType, Arg)) {
     case NPV_NullPointer:
       S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
-      Converted = TemplateArgument((Decl *)0);
+      Converted = TemplateArgument(ParamType, /*isNullPtr*/true);
       return false;
 
     case NPV_Error:
@@ -3767,7 +3759,7 @@ CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
     return true;
   }
 
-  NamedDecl *Entity = DRE->getDecl();
+  ValueDecl *Entity = DRE->getDecl();
 
   // Cannot refer to non-static data members
   if (FieldDecl *Field = dyn_cast<FieldDecl>(Entity)) {
@@ -3955,7 +3947,8 @@ CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
   }
 
   // Create the template argument.
-  Converted = TemplateArgument(Entity->getCanonicalDecl());
+  Converted = TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()),
+                               ParamType->isReferenceType());
   S.MarkAnyDeclReferenced(Arg->getLocStart(), Entity);
   return false;
 }
@@ -3976,7 +3969,7 @@ static bool CheckTemplateArgumentPointerToMember(Sema &S,
     return true;
   case NPV_NullPointer:
     S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
-    Converted = TemplateArgument((Decl *)0);
+    Converted = TemplateArgument(ParamType, /*isNullPtr*/true);
     return false;
   case NPV_NotNullPointer:
     break;
@@ -4045,10 +4038,12 @@ static bool CheckTemplateArgumentPointerToMember(Sema &S,
         if (isa<NonTypeTemplateParmDecl>(VD) ||
             (isa<VarDecl>(VD) &&
              S.Context.getCanonicalType(VD->getType()).isConstQualified())) {
-          if (Arg->isTypeDependent() || Arg->isValueDependent())
+          if (Arg->isTypeDependent() || Arg->isValueDependent()) {
             Converted = TemplateArgument(Arg);
-          else
-            Converted = TemplateArgument(VD->getCanonicalDecl());
+          } else {
+            VD = cast<ValueDecl>(VD->getCanonicalDecl());
+            Converted = TemplateArgument(VD, /*isReferenceParam*/false);
+          }
           return Invalid;
         }
       }
@@ -4069,10 +4064,12 @@ static bool CheckTemplateArgumentPointerToMember(Sema &S,
 
     // Okay: this is the address of a non-static member, and therefore
     // a member pointer constant.
-    if (Arg->isTypeDependent() || Arg->isValueDependent())
+    if (Arg->isTypeDependent() || Arg->isValueDependent()) {
       Converted = TemplateArgument(Arg);
-    else
-      Converted = TemplateArgument(DRE->getDecl()->getCanonicalDecl());
+    } else {
+      ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
+      Converted = TemplateArgument(D, /*isReferenceParam*/false);
+    }
     return Invalid;
   }
 
@@ -4425,7 +4422,7 @@ ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
       
     case NPV_NullPointer:
       Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
-      Converted = TemplateArgument((Decl *)0);
+      Converted = TemplateArgument(ParamType, /*isNullPtr*/true);
       return Owned(Arg);
     }
   }
@@ -4448,7 +4445,7 @@ ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
 bool Sema::CheckTemplateArgument(TemplateTemplateParmDecl *Param,
                                  const TemplateArgumentLoc &Arg,
                                  unsigned ArgumentPackIndex) {
-  TemplateName Name = Arg.getArgument().getAsTemplate();
+  TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
   TemplateDecl *Template = Name.getAsTemplateDecl();
   if (!Template) {
     // Any dependent template name is fine.
@@ -4497,12 +4494,9 @@ ExprResult
 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
                                               QualType ParamType,
                                               SourceLocation Loc) {
-  assert(Arg.getKind() == TemplateArgument::Declaration &&
-         "Only declaration template arguments permitted here");
-  
   // For a NULL non-type template argument, return nullptr casted to the
   // parameter's type.
-  if (!Arg.getAsDecl()) {
+  if (Arg.getKind() == TemplateArgument::NullPtr) {
     return ImpCastExprToType(
              new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
                              ParamType,
@@ -4510,7 +4504,9 @@ Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
                                ? CK_NullToMemberPointer
                                : CK_NullToPointer);
   }
-  
+  assert(Arg.getKind() == TemplateArgument::Declaration &&
+         "Only declaration template arguments permitted here");
+
   ValueDecl *VD = cast<ValueDecl>(Arg.getAsDecl());
 
   if (VD->getDeclContext()->isRecord() &&
@@ -5105,10 +5101,10 @@ static bool CheckNonTypeClassTemplatePartialSpecializationArgs(Sema &S,
       continue;
     }
 
-    Expr *ArgExpr = Args[I].getAsExpr();
-    if (!ArgExpr) {
+    if (Args[I].getKind() != TemplateArgument::Expression)
       continue;
-    }
+
+    Expr *ArgExpr = Args[I].getAsExpr();
 
     // We can have a pack expansion of any of the bullets below.
     if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))