improve comment, no functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72386 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/TokenLexer.cpp b/lib/Lex/TokenLexer.cpp
index 65d083d..5675f3f 100644
--- a/lib/Lex/TokenLexer.cpp
+++ b/lib/Lex/TokenLexer.cpp
@@ -220,16 +220,21 @@
ResultToks.append(ArgToks, ArgToks+NumToks);
- // If the next token was supposed to get leading whitespace, ensure it has
- // it now.
- if (CurTok.hasLeadingSpace() || NextTokGetsSpace) {
- // Exception: the RHS of a paste doesn't get whitespace. This allows
- // constructs like conacatenating a period and an identifer to work
- // correctly in assembler-with-cpp.
- if (!PasteBefore)
- ResultToks[ResultToks.size()-NumToks].setFlag(Token::LeadingSpace);
- NextTokGetsSpace = false;
- }
+ // If this token (the macro argument) was supposed to get leading
+ // whitespace, transfer this information onto the first token of the
+ // expansion.
+ //
+ // Do not do this if the paste operator occurs before the macro argument,
+ // as in "A ## MACROARG". In valid code, the first token will get
+ // smooshed onto the preceding one anyway (forming AMACROARG). In
+ // assembler-with-cpp mode, invalid pastes are allowed through: in this
+ // case, we do not want the extra whitespace to be added. For example,
+ // we want ". ## foo" -> ".foo" not ". foo".
+ if ((CurTok.hasLeadingSpace() || NextTokGetsSpace) &&
+ !PasteBefore)
+ ResultToks[ResultToks.size()-NumToks].setFlag(Token::LeadingSpace);
+
+ NextTokGetsSpace = false;
continue;
}