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| author | Jakub Jelinek <jakub@redhat.com> | 2025-09-01 21:55:49 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2025-09-01 21:55:49 +0200 |
| commit | a4d066f3643d3df5929425767130d68e8a775241 (patch) | |
| tree | 71006e3f899563bcef0cc192a6cb99a670ea8842 | |
| parent | 086d0d8c9cbd9625b6e1af1146c014662ff96ae2 (diff) | |
| download | gcc-a4d066f3643d3df5929425767130d68e8a775241.zip gcc-a4d066f3643d3df5929425767130d68e8a775241.tar.gz gcc-a4d066f3643d3df5929425767130d68e8a775241.tar.bz2 | |
c: Implement C2Y N3457 - The __COUNTER__ predefined macro
The following patch implements the
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3457.htm
paper without the first 3 lines in Recommended practice.
Seems GCC behavior already matches the expected behavior except for
diagnostics of more than 2147483648 __COUNTER__ expansions, so the
patch adds a diagnostic for that (but not testcase because
#define A __COUNTER__ __COUNTER__ __COUNTER__ __COUNTER__ __COUNTER__ __COUNTER__ __COUNTER__ __COUNTER__
#define B A A A A A A A A
#define C B B B B B B B B
#define D C C C C C C C C
#define E D D D D D D D D
#define F E E E E E E E E
#define G F F F F F F F F
#define H G G G G G G G G
#define I H H H H H H H H
#define J I I I I I I I I
J J J J
__COUNTER__
just takes too long to preprocess).
Plus I've included all the snippets from the paper into one testcase.
2025-09-01 Jakub Jelinek <jakub@redhat.com>
* macro.cc: Implement C2Y N3457 - The __COUNTER__ predefined macro.
(_cpp_builtin_macro_text): Diagnose if __COUNTER__ reaches
2147483648 value.
* gcc.dg/cpp/c2y-counter-1.c: New test.
| -rw-r--r-- | gcc/testsuite/gcc.dg/cpp/c2y-counter-1.c | 44 | ||||
| -rw-r--r-- | libcpp/macro.cc | 3 |
2 files changed, 47 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/cpp/c2y-counter-1.c b/gcc/testsuite/gcc.dg/cpp/c2y-counter-1.c new file mode 100644 index 0000000..47d4b23 --- /dev/null +++ b/gcc/testsuite/gcc.dg/cpp/c2y-counter-1.c @@ -0,0 +1,44 @@ +/* N3457 - The __COUNTER__ predefined macro */ +/* { dg-do run } */ +/* { dg-options "-std=c2y -pedantic-errors" } */ + +#ifndef __COUNTER__ +#error "__COUNTER__ not defined" +#endif + +#define A(X) X + X +static_assert (A(__COUNTER__) == 0); +#define B(X) +B(__COUNTER__) +static_assert (__COUNTER__ == 1); +#define C(...) __VA_OPT__() +C(__COUNTER__) +static_assert (__COUNTER__ == 3); +#define D(...) __VA_OPT__(a) +int D(__COUNTER__) = 1; +static_assert (__COUNTER__ == 5); +#define E(X) #X +const char *b = E(__COUNTER__); +#define F(X) a##X +int F(__COUNTER__) = 2; +static_assert (__COUNTER__ == 6); +#define G(X) b##X = X +int G(__COUNTER__); +static_assert (__COUNTER__ == 8); +#if !defined(__COUNTER__) || (__COUNTER__ + 1 != __COUNTER__ + 0) +#error "Unexpected __COUNTER__ behavior") +#endif +static_assert (__COUNTER__ == 11); + +extern int strcmp (const char *, const char *); +extern void abort (); + +int +main () +{ + if (a != 1 + || strcmp (b, "__COUNTER__") + || a__COUNTER__ != 2 + || b__COUNTER__ != 7) + abort (); +} diff --git a/libcpp/macro.cc b/libcpp/macro.cc index 9867098..e307602 100644 --- a/libcpp/macro.cc +++ b/libcpp/macro.cc @@ -733,6 +733,9 @@ _cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node, "%<__COUNTER__%> expanded inside directive with " "%<-fdirectives-only%>"); number = pfile->counter++; + if (number == 0x80000000U) + cpp_error (pfile, CPP_DL_ERROR, + "%<__COUNTER__%> expanded more than 2147483648 times"); break; case BT_HAS_ATTRIBUTE: |