[NFC] Refactor the Preprocessor function that handles Macro definitions and rename Arguments to Parameters in Macro Definitions. 
  - Extracted the reading of the tokens out into a separate function.
  - Replace 'Argument' with 'Parameter' when referring to the identifiers of the macro definition (as opposed to the supplied arguments - MacroArgs - during the macro invocation).

This is in preparation for submitting patches for review to implement __VA_OPT__ which will otherwise just keep lengthening the HandleDefineDirective function and making it less comprehensible.

I will also directly update some extra clang tooling that is broken by the change from Argument to Parameter.

Hopefully the bots will stay appeased.

Thanks!

llvm-svn: 308190
diff --git a/clang/lib/Lex/MacroInfo.cpp b/clang/lib/Lex/MacroInfo.cpp
index 1e5deeb..6dc7841 100644
--- a/clang/lib/Lex/MacroInfo.cpp
+++ b/clang/lib/Lex/MacroInfo.cpp
@@ -17,8 +17,8 @@
 
 MacroInfo::MacroInfo(SourceLocation DefLoc)
   : Location(DefLoc),
-    ArgumentList(nullptr),
-    NumArguments(0),
+    ParameterList(nullptr),
+    NumParameters(0),
     IsDefinitionLengthCached(false),
     IsFunctionLike(false),
     IsC99Varargs(false),
@@ -74,7 +74,7 @@
 
   // Check # tokens in replacement, number of args, and various flags all match.
   if (ReplacementTokens.size() != Other.ReplacementTokens.size() ||
-      getNumArgs() != Other.getNumArgs() ||
+      getNumParams() != Other.getNumParams() ||
       isFunctionLike() != Other.isFunctionLike() ||
       isC99Varargs() != Other.isC99Varargs() ||
       isGNUVarargs() != Other.isGNUVarargs())
@@ -82,7 +82,8 @@
 
   if (Lexically) {
     // Check arguments.
-    for (arg_iterator I = arg_begin(), OI = Other.arg_begin(), E = arg_end();
+    for (param_iterator I = param_begin(), OI = Other.param_begin(),
+                        E = param_end();
          I != E; ++I, ++OI)
       if (*I != *OI) return false;
   }
@@ -109,10 +110,10 @@
         return false;
       // With syntactic equivalence the parameter names can be different as long
       // as they are used in the same place.
-      int AArgNum = getArgumentNum(A.getIdentifierInfo());
+      int AArgNum = getParameterNum(A.getIdentifierInfo());
       if (AArgNum == -1)
         return false;
-      if (AArgNum != Other.getArgumentNum(B.getIdentifierInfo()))
+      if (AArgNum != Other.getParameterNum(B.getIdentifierInfo()))
         return false;
       continue;
     }
@@ -141,12 +142,12 @@
   Out << "\n    #define <macro>";
   if (IsFunctionLike) {
     Out << "(";
-    for (unsigned I = 0; I != NumArguments; ++I) {
+    for (unsigned I = 0; I != NumParameters; ++I) {
       if (I) Out << ", ";
-      Out << ArgumentList[I]->getName();
+      Out << ParameterList[I]->getName();
     }
     if (IsC99Varargs || IsGNUVarargs) {
-      if (NumArguments && IsC99Varargs) Out << ", ";
+      if (NumParameters && IsC99Varargs) Out << ", ";
       Out << "...";
     }
     Out << ")";