Hi!
In the following testcase we incorrectly error about pasting / token
with padding token (which is a result of __VA_OPT__); instead we should
like e.g. for ##arg where arg is empty macro argument clear PASTE_LEFT
flag of the previous token if __VA_OPT__ doesn't add any real tokens
(which can happen either because the macro doesn't have any tokens
passed to ... (i.e. __VA_ARGS__ expands to empty) or when __VA_OPT__
doesn't have any tokens in between ()s).
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok
for trunk?
2021-12-30 Jakub Jelinek <ja...@redhat.com>
PR preprocessor/89971
libcpp/
* macro.c (replace_args): For ##__VA_OPT__, if __VA_OPT__ expands
to no tokens at all, drop PASTE_LEFT flag from the previous token.
gcc/testsuite/
* c-c++-common/cpp/va-opt-9.c: New test.
--- libcpp/macro.c.jj 2021-12-01 10:07:46.774663941 +0100
+++ libcpp/macro.c 2021-12-29 15:22:09.393455799 +0100
@@ -2094,8 +2094,14 @@ replace_args (cpp_reader *pfile, cpp_has
tokens_buff_add_token (buff, virt_locs,
t, t->src_loc, t->src_loc,
NULL, 0);
+ continue;
}
- else if (src->flags & PASTE_LEFT)
+ if (start && paste_flag == start && (*start)->flags & PASTE_LEFT)
+ /* If __VA_OPT__ expands to nothing (either because __VA_ARGS__
+ is empty or because it is __VA_OPT__() ), drop PASTE_LEFT
+ flag from previous token. */
+ copy_paste_flag (pfile, start, &pfile->avoid_paste);
+ if (src->flags & PASTE_LEFT)
{
/* Don't avoid paste after all. */
while (paste_flag && paste_flag != start
--- gcc/testsuite/c-c++-common/cpp/va-opt-9.c.jj 2021-12-29
15:30:48.231203467 +0100
+++ gcc/testsuite/c-c++-common/cpp/va-opt-9.c 2021-12-29 15:40:12.676317163
+0100
@@ -0,0 +1,20 @@
+/* PR preprocessor/89971 */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99" { target c } } */
+/* { dg-options "-std=c++20" { target c++ } } */
+
+int a, c;
+#define m1(...) a /##__VA_OPT__(b) c
+#define m2(...) a /##__VA_OPT__() c
+#define m3(...) a##__VA_OPT__()##b = 1
+#define m4(...) a##__VA_OPT__(b c d)##e = 2
+
+int
+foo (void)
+{
+ int d = m1();
+ int e = m2(1);
+ int m3(1 2 3);
+ int m4();
+ return d + e + ab + ae;
+}
Jakub
