Update Append Argument to more efficiently traverse tokens

This function was previously making (correct) assumptions
without complete knowledge of MacroArgs guarantees for
Arguments.  After going through Macro Args a bunch, I'd
corrected the getNumArguments (and changed its name), 
however didn't realize this was depending on the behavior.

This patch has version that depends on the corrected 
getNumMacroArguments's behavior, with the rest checked against
my knowledge of the MacroArgs' token list.  Commiting no-wait
since the test is broken.

llvm-svn: 305434

clang-tools-extra/pp-trace/PPCallbacksTracker.cpp

@@ -588,19 +588,16 @@ void PPCallbacksTracker::appendArgument(const char *Name,
   std::string Str;
   llvm::raw_string_ostream SS(Str);
   SS << "[";
-  // The argument tokens might include end tokens, so we reflect how
-  // how getUnexpArgument provides the arguments.
-  for (int I = 0, E = Value->getNumMacroArguments(); I < E; ++I) {
+
+  // Each argument is is a series of contiguous Tokens, terminated by a eof.
+  // Go through each argument printing tokens until we reach eof.
+  for (unsigned I = 0; I < Value->getNumMacroArguments(); ++I) {
     const clang::Token *Current = Value->getUnexpArgument(I);
-    int TokenCount = Value->getArgLength(Current) + 1; // include EOF
-    E -= TokenCount;
     if (I)
       SS << ", ";
-    // We're assuming tokens are contiguous, as otherwise we have no
-    // other way to get at them.
-    --TokenCount;
-    for (int TokenIndex = 0; TokenIndex < TokenCount; ++TokenIndex, ++Current) {
-      if (TokenIndex)
+    bool First = true;
+    while (Current->isNot(clang::tok::eof)) {
+      if (!First)
         SS << " ";
       // We need to be careful here because the arguments might not be legal in
       // YAML, so we use the token name for anything but identifiers and
@@ -611,6 +608,8 @@ void PPCallbacksTracker::appendArgument(const char *Name,
       } else {
         SS << "<" << Current->getName() << ">";
       }
+      ++Current;
+      First = false;
     }
   }
   SS << "]";