[flang] Fix handling of space between # and name in preprocessor stringification

When preprocessing "# ARG" in function-like macro expansion,
the preprocessor needs to pop the previously-pushed '#' token
from the end of the resulting token sequence after detecting the
argument name.  The code to do this was just wrong in a couple of
ways.

Differential Revision: https://reviews.llvm.org/D117148

1 files changed, 2 insertions, 1 deletions

diff --git a/flang/lib/Parser/preprocessor.cpp b/flang/lib/Parser/preprocessor.cpp
index de85e8e..46b62a4 100644
--- a/flang/lib/Parser/preprocessor.cpp
+++ b/flang/lib/Parser/preprocessor.cpp
@@ -169,8 +169,9 @@ TokenSequence Definition::Apply(
           replacement_.TokenAt(prev - 1)[0] ==
               '#') { // stringify argument without macro replacement
         std::size_t resultSize{result.SizeInTokens()};
-        while (resultSize > 0 && result.TokenAt(resultSize - 1).empty()) {
+        while (resultSize > 0 && result.TokenAt(resultSize - 1).IsBlank()) {
           result.pop_back();
+          --resultSize;
         }
         CHECK(resultSize > 0 &&
             result.TokenAt(resultSize - 1) == replacement_.TokenAt(prev - 1));