Rename FunctionProtoType accessors from 'arguments' to 'parameters'

Fix a perennial source of confusion in the clang type system: Declarations and
function prototypes have parameters to which arguments are supplied, so calling
these 'arguments' was a stretch even in C mode, let alone C++ where default
arguments, templates and overloading make the distinction important to get
right.

Readability win across the board, especially in the casting, ADL and
overloading implementations which make a lot more sense at a glance now.

Will keep an eye on the builders and update dependent projects shortly.

No functional change.

llvm-svn: 199686
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 608f11c..df4d66e 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -714,8 +714,9 @@
                                          const FunctionDecl *FD) {
   unsigned ArgIndex = 0;
   const FunctionProtoType *FT = FD->getType()->getAs<FunctionProtoType>();
-  for (FunctionProtoType::arg_type_iterator i = FT->arg_type_begin(),
-       e = FT->arg_type_end(); i != e; ++i, ++ArgIndex) {
+  for (FunctionProtoType::param_type_iterator i = FT->param_type_begin(),
+                                              e = FT->param_type_end();
+       i != e; ++i, ++ArgIndex) {
     const ParmVarDecl *PD = FD->getParamDecl(ArgIndex);
     SourceLocation ParamLoc = PD->getLocation();
     if (!(*i)->isDependentType() &&
@@ -4717,7 +4718,7 @@
   FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
   ExceptSpec.getEPI(EPI);
   FD->setType(S.Context.getFunctionType(FPT->getResultType(),
-                                        FPT->getArgTypes(), EPI));
+                                        FPT->getParamTypes(), EPI));
 }
 
 static FunctionProtoType::ExtProtoInfo getImplicitMethodEPI(Sema &S,
@@ -4822,7 +4823,7 @@
   }
 
   // Check for parameter type matching.
-  QualType ArgType = ExpectedParams ? Type->getArgType(0) : QualType();
+  QualType ArgType = ExpectedParams ? Type->getParamType(0) : QualType();
   bool HasConstParam = false;
   if (ExpectedParams && ArgType->isReferenceType()) {
     // Argument must be reference to possibly-const T.
@@ -6225,8 +6226,8 @@
   FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
   EPI.TypeQuals = 0;
   EPI.RefQualifier = RQ_None;
-  
-  return Context.getFunctionType(Context.VoidTy, Proto->getArgTypes(), EPI);
+
+  return Context.getFunctionType(Context.VoidTy, Proto->getParamTypes(), EPI);
 }
 
 /// CheckConstructor - Checks a fully-formed constructor for
@@ -6454,7 +6455,7 @@
   const FunctionProtoType *Proto = R->getAs<FunctionProtoType>();
 
   // Make sure we don't have any parameters.
-  if (Proto->getNumArgs() > 0) {
+  if (Proto->getNumParams() > 0) {
     Diag(D.getIdentifierLoc(), diag::err_conv_function_with_params);
 
     // Delete the parameters.
@@ -8388,7 +8389,7 @@
   void inherit(const CXXConstructorDecl *Ctor) {
     const FunctionProtoType *CtorType =
         Ctor->getType()->castAs<FunctionProtoType>();
-    ArrayRef<QualType> ArgTypes(CtorType->getArgTypes());
+    ArrayRef<QualType> ArgTypes(CtorType->getParamTypes());
     FunctionProtoType::ExtProtoInfo EPI = CtorType->getExtProtoInfo();
 
     SourceLocation UsingLoc = getUsingLoc(Ctor->getParent());
@@ -8531,16 +8532,16 @@
     EPI.ExceptionSpecType = EST_Unevaluated;
     EPI.ExceptionSpecDecl = DerivedCtor;
     DerivedCtor->setType(Context.getFunctionType(FPT->getResultType(),
-                                                 FPT->getArgTypes(), EPI));
+                                                 FPT->getParamTypes(), EPI));
 
     // Build the parameter declarations.
     SmallVector<ParmVarDecl *, 16> ParamDecls;
-    for (unsigned I = 0, N = FPT->getNumArgs(); I != N; ++I) {
+    for (unsigned I = 0, N = FPT->getNumParams(); I != N; ++I) {
       TypeSourceInfo *TInfo =
-          Context.getTrivialTypeSourceInfo(FPT->getArgType(I), UsingLoc);
+          Context.getTrivialTypeSourceInfo(FPT->getParamType(I), UsingLoc);
       ParmVarDecl *PD = ParmVarDecl::Create(
           Context, DerivedCtor, UsingLoc, UsingLoc, /*IdentifierInfo=*/0,
-          FPT->getArgType(I), TInfo, SC_None, /*DefaultArg=*/0);
+          FPT->getParamType(I), TInfo, SC_None, /*DefaultArg=*/0);
       PD->setScopeInfo(0, I);
       PD->setImplicit();
       ParamDecls.push_back(PD);
@@ -9237,8 +9238,9 @@
     return ExceptSpec;
 
   const FunctionProtoType *T = MD->getType()->castAs<FunctionProtoType>();
-  assert(T->getNumArgs() == 1 && "not a copy assignment op");
-  unsigned ArgQuals = T->getArgType(0).getNonReferenceType().getCVRQualifiers();
+  assert(T->getNumParams() == 1 && "not a copy assignment op");
+  unsigned ArgQuals =
+      T->getParamType(0).getNonReferenceType().getCVRQualifiers();
 
   // C++ [except.spec]p14:
   //   An implicitly declared special member function (Clause 12) shall have an
@@ -10061,8 +10063,8 @@
     return ExceptSpec;
 
   const FunctionProtoType *T = MD->getType()->castAs<FunctionProtoType>();
-  assert(T->getNumArgs() >= 1 && "not a copy ctor");
-  unsigned Quals = T->getArgType(0).getNonReferenceType().getCVRQualifiers();
+  assert(T->getNumParams() >= 1 && "not a copy ctor");
+  unsigned Quals = T->getParamType(0).getNonReferenceType().getCVRQualifiers();
 
   // C++ [except.spec]p14:
   //   An implicitly declared special member function (Clause 12) shall have an 
@@ -10635,8 +10637,8 @@
   const FunctionProtoType *Proto 
     = Constructor->getType()->getAs<FunctionProtoType>();
   assert(Proto && "Constructor without a prototype?");
-  unsigned NumArgsInProto = Proto->getNumArgs();
-  
+  unsigned NumArgsInProto = Proto->getNumParams();
+
   // If too few arguments are available, we'll fill in the rest with defaults.
   if (NumArgs < NumArgsInProto)
     ConvertedArgs.reserve(NumArgsInProto);