On Mon, Nov 29, 2021 at 07:28:10PM -0500, Jason Merrill wrote:
> Please add some of this explanation to the "paste any tokens" comment in the
> code.
Ok.
> > + while (rhs->flags & PASTE_LEFT);
> > + if ((flags & PREV_WHITE)
> > + && (token->flags & PREV_WHITE) == 0)
> > + const_cast<cpp_token *>(token)->flags
> > + |= PREV_WHITE;
>
> Hmm, shouldn't paste_tokens handle copying PREV_WHITE?
Copying there PREV_FALLTHROUGH fixes the new Wimplicit-fallthrough-38.c
testcase, I couldn't find where doing the copying of PREV_WHITE would
make an observable difference outside of __VA_OPT__, e.g.
#define F(x) #x
#define G(x) F(x)
#define H G({a##b)
#define I G({ a##b)
const char *h = H;
const char *i = I;
results in "{ab" and "{ ab" before/after the patch. But copying it
in paste_tokens looks cleaner...
2021-11-30 Jakub Jelinek <ja...@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 2021-11-26 10:09:50.278020239 +0100
+++ libcpp/macro.c 2021-11-30 14:05:25.274132482 +0100
@@ -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 *);
@@ -834,8 +834,7 @@ 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;
@@ -852,24 +851,6 @@ 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
@@ -1003,6 +984,7 @@ paste_tokens (cpp_reader *pfile, locatio
return false;
}
+ lhs->flags |= (*plhs)->flags & (PREV_WHITE | PREV_FALLTHROUGH);
*plhs = lhs;
_cpp_pop_buffer (pfile);
return true;
@@ -1945,8 +1927,7 @@ 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)))
@@ -2066,11 +2047,46 @@ 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 2021-11-30
13:59:28.277305079 +0100
+++ gcc/testsuite/c-c++-common/cpp/va-opt-8.c 2021-11-30 13:59:28.277305079
+0100
@@ -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 2021-11-30
14:10:16.309915336 +0100
+++ gcc/testsuite/c-c++-common/Wimplicit-fallthrough-38.c 2021-11-30
14:10:33.708663223 +0100
@@ -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
Jakub
