libcpp: Fix up #__VA_OPT__ handling [PR103415]
stringify_arg uses pfile->u_buff to create the string literal.
Unfortunately, paste_tokens -> _cpp_lex_direct -> lex_number -> _cpp_unaligned_alloc
can in some cases use pfile->u_buff too, which results in losing everything
prepared for the string literal until the token pasting.
The following patch fixes that by not calling paste_token during the
construction of the string literal, but doing that before. All the tokens
we are processing have been pushed into a token buffer using
tokens_buff_add_token so it is fine if we paste some of them in that buffer
(successful pasting creates a new token in that buffer), move following
tokens if any to make it contiguous, pop (throw away) the extra tokens at
the end and then do stringify_arg.
Also, paste_tokens now copies over PREV_WHITE and PREV_FALLTHROUGH flags
from the original lhs token to the replacement token. Copying that way
the PREV_WHITE flag is needed for the #__VA_OPT__ handling and copying
over PREV_FALLTHROUGH fixes the new Wimplicit-fallthrough-38.c test.
2021-12-01 Jakub Jelinek <jakub@redhat.com>
PR preprocessor/103415
libcpp/
* macro.c (stringify_arg): Remove va_opt argument and va_opt handling.
(paste_tokens): On successful paste or in PREV_WHITE and
PREV_FALLTHROUGH flags from the *plhs token to the new token.
(replace_args): Adjust stringify_arg callers. For #__VA_OPT__,
perform token pasting in a separate loop before stringify_arg call.
gcc/testsuite/
* c-c++-common/cpp/va-opt-8.c: New test.
* c-c++-common/Wimplicit-fallthrough-38.c: New test.
--- libcpp/macro.c.jj
+++ libcpp/macro.c
@@ -295,7 +295,7 @@ static cpp_context *next_context (cpp_re
static const cpp_token *padding_token (cpp_reader *, const cpp_token *);
static const cpp_token *new_string_token (cpp_reader *, uchar *, unsigned int);
static const cpp_token *stringify_arg (cpp_reader *, const cpp_token **,
- unsigned int, bool);
+ unsigned int);
static void paste_all_tokens (cpp_reader *, const cpp_token *);
static bool paste_tokens (cpp_reader *, location_t,
const cpp_token **, const cpp_token *);
@@ -826,8 +826,7 @@ cpp_quote_string (uchar *dest, const uch
/* Convert a token sequence FIRST to FIRST+COUNT-1 to a single string token
according to the rules of the ISO C #-operator. */
static const cpp_token *
-stringify_arg (cpp_reader *pfile, const cpp_token **first, unsigned int count,
- bool va_opt)
+stringify_arg (cpp_reader *pfile, const cpp_token **first, unsigned int count)
{
unsigned char *dest;
unsigned int i, escape_it, backslash_count = 0;
@@ -844,24 +843,6 @@ stringify_arg (cpp_reader *pfile, const
{
const cpp_token *token = first[i];
- if (va_opt && (token->flags & PASTE_LEFT))
- {
- location_t virt_loc = pfile->invocation_location;
- const cpp_token *rhs;
- do
- {
- if (i == count)
- abort ();
- rhs = first[++i];
- if (!paste_tokens (pfile, virt_loc, &token, rhs))
- {
- --i;
- break;
- }
- }
- while (rhs->flags & PASTE_LEFT);
- }
-
if (token->type == CPP_PADDING)
{
if (source == NULL
@@ -995,6 +976,7 @@ paste_tokens (cpp_reader *pfile, locatio
return false;
}
+ lhs->flags |= (*plhs)->flags & (PREV_WHITE | PREV_FALLTHROUGH);
*plhs = lhs;
_cpp_pop_buffer (pfile);
return true;
@@ -1937,8 +1919,7 @@ replace_args (cpp_reader *pfile, cpp_has
if (src->flags & STRINGIFY_ARG)
{
if (!arg->stringified)
- arg->stringified = stringify_arg (pfile, arg->first, arg->count,
- false);
+ arg->stringified = stringify_arg (pfile, arg->first, arg->count);
}
else if ((src->flags & PASTE_LEFT)
|| (src != macro->exp.tokens && (src[-1].flags & PASTE_LEFT)))
@@ -2065,11 +2046,46 @@ replace_args (cpp_reader *pfile, cpp_has
{
unsigned int count
= start ? paste_flag - start : tokens_buff_count (buff);
- const cpp_token *t
- = stringify_arg (pfile,
- start ? start + 1
- : (const cpp_token **) (buff->base),
- count, true);
+ const cpp_token **first
+ = start ? start + 1
+ : (const cpp_token **) (buff->base);
+ unsigned int i, j;
+
+ /* Paste any tokens that need to be pasted before calling
+ stringify_arg, because stringify_arg uses pfile->u_buff
+ which paste_tokens can use as well. */
+ for (i = 0, j = 0; i < count; i++, j++)
+ {
+ const cpp_token *token = first[i];
+
+ if (token->flags & PASTE_LEFT)
+ {
+ location_t virt_loc = pfile->invocation_location;
+ const cpp_token *rhs;
+ do
+ {
+ if (i == count)
+ abort ();
+ rhs = first[++i];
+ if (!paste_tokens (pfile, virt_loc, &token, rhs))
+ {
+ --i;
+ break;
+ }
+ }
+ while (rhs->flags & PASTE_LEFT);
+ }
+
+ first[j] = token;
+ }
+ if (j != i)
+ {
+ while (i-- != j)
+ tokens_buff_remove_last_token (buff);
+ count = j;
+ }
+
+ const cpp_token *t = stringify_arg (pfile, first, count);
while (count--)
tokens_buff_remove_last_token (buff);
if (src->flags & PASTE_LEFT)
--- gcc/testsuite/c-c++-common/cpp/va-opt-8.c.jj
+++ gcc/testsuite/c-c++-common/cpp/va-opt-8.c
@@ -0,0 +1,18 @@
+/* PR preprocessor/103415 */
+/* { dg-do run } */
+/* { dg-options "-std=gnu99" { target c } } */
+/* { dg-options "-std=c++20" { target c++ } } */
+
+#define n(x, ...) = #__VA_OPT__(x##3)
+#define o(x, ...) #__VA_OPT__(x##__VA_ARGS__##9)
+const char *c n(1 2, 4);
+const char *d = o(5 6, 7 8);
+
+int
+main ()
+{
+ if (__builtin_strcmp (c, "1 23")
+ || __builtin_strcmp (d, "5 67 89"))
+ __builtin_abort ();
+ return 0;
+}
--- gcc/testsuite/c-c++-common/Wimplicit-fallthrough-38.c.jj
+++ gcc/testsuite/c-c++-common/Wimplicit-fallthrough-38.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-Wimplicit-fallthrough=3" } */
+
+#define FOO \
+int \
+foo (int a) \
+{ \
+ switch (a) \
+ { \
+ case 1: \
+ ++a; \
+ /* FALLTHRU */ \
+ case 2: \
+ ++a; \
+ /* FALLTHRU */ \
+ ca##se 3: \
+ ++a; \
+ default: \
+ break; \
+ } \
+ return a; \
+}
+
+FOO