add better comments.
llvm-svn: 39904
diff --git a/clang/Driver/TextDiagnosticPrinter.cpp b/clang/Driver/TextDiagnosticPrinter.cpp
index 1acd210..f1a36ba 100644
--- a/clang/Driver/TextDiagnosticPrinter.cpp
+++ b/clang/Driver/TextDiagnosticPrinter.cpp
@@ -101,12 +101,14 @@
/// GetTokenLength - Given the source location of a token, determine its length.
/// This is a fully general function that uses a lexer to relex the token.
unsigned TextDiagnosticPrinter::GetTokenLength(SourceLocation Loc) {
- const char *StrData =
- SourceMgr.getCharacterData(SourceMgr.getLogicalLoc(Loc));
+ // If this comes from a macro expansion, we really do want the macro name, not
+ // the token this macro expanded to.
+ Loc = SourceMgr.getLogicalLoc(Loc);
+ const char *StrData = SourceMgr.getCharacterData(Loc);
- // Note, this could be special cased for common tokens like identifiers, ')',
- // etc to make this faster, if it mattered.
-
+ // TODO: this could be special cased for common tokens like identifiers, ')',
+ // etc to make this faster, if it mattered. This could use
+ // Lexer::isObviouslySimpleCharacter for example.
unsigned FileID = Loc.getFileID();
// Create a lexer starting at the beginning of this token.