Rename CommentIndex -> LineStartIndex, comment index-related members

Author: s-barannikov

llvm/utils/TableGen/DecoderTableEmitter.cpp

@@ -132,7 +132,7 @@ unsigned DecoderTableEmitter::computeTableSize(const DecoderTreeNode *Root,
 }
 
 void DecoderTableEmitter::emitStartLine() {
-  CommentIndex = CurrentIndex;
+  LineStartIndex = CurrentIndex;
   OS.indent(2);
 }
 
@@ -165,7 +165,7 @@ raw_ostream &DecoderTableEmitter::emitComment(indent Indent) {
   if (OS.getColumn() > CommentColumn)
     OS << '\n';
   OS.PadToColumn(CommentColumn);
-  OS << "// " << format_decimal(CommentIndex, IndexWidth) << ": " << Indent;
+  OS << "// " << format_decimal(LineStartIndex, IndexWidth) << ": " << Indent;
   return OS;
 }
 

llvm/utils/TableGen/DecoderTableEmitter.h

@@ -49,9 +49,18 @@ struct DecoderTableInfo {
 class DecoderTableEmitter {
   DecoderTableInfo &TableInfo;
   formatted_raw_ostream OS;
+
+  /// The number of positions occupied by the index in the output. Used to
+  /// right-align indices and left-align the text that follows them.
   unsigned IndexWidth;
+
+  /// The current position in the output stream. After the table is emitted,
+  /// this is its size.
   unsigned CurrentIndex;
-  unsigned CommentIndex;
+
+  /// The index of the first byte of the table row. Used as a label in the
+  /// comment following the row.
+  unsigned LineStartIndex;
 
 public:
   DecoderTableEmitter(DecoderTableInfo &TableInfo, raw_ostream &OS)