Author: Aaron Ballman Date: 2024-03-20T15:08:43-04:00 New Revision: 7955bde64ef9aebbcaf6b6308a25fac31041ea9a
URL: https://github.com/llvm/llvm-project/commit/7955bde64ef9aebbcaf6b6308a25fac31041ea9a DIFF: https://github.com/llvm/llvm-project/commit/7955bde64ef9aebbcaf6b6308a25fac31041ea9a.diff LOG: [C11] Add test coverage for N1310 and claim conformance This is about the best I could do for testing that `signed char` does not have any padding bits. Added: clang/test/C/C11/n1310.c Modified: clang/www/c_status.html Removed: ################################################################################ diff --git a/clang/test/C/C11/n1310.c b/clang/test/C/C11/n1310.c new file mode 100644 index 00000000000000..7f8dd754f74631 --- /dev/null +++ b/clang/test/C/C11/n1310.c @@ -0,0 +1,31 @@ +// RUN: %clang_cc1 -verify -std=c89 %s +// RUN: %clang_cc1 -verify -std=c99 %s +// RUN: %clang_cc1 -verify -std=c11 %s +// RUN: %clang_cc1 -verify -std=c17 %s +// RUN: %clang_cc1 -verify -std=c23 %s +// expected-no-diagnostics + +/* WG14 N1310: Yes + * Requiring signed char to have no padding bits + */ + +/* This is shockingly hard to test, but we're trying our best by checking that + * setting each bit of an unsigned char, then bit-casting it to signed char, + * results in a value we expect to see. If we have padding bits, then it's + * possible (but not mandatory) for the value to not be as we expect, so a + * failing assertion means the implementation is broken but a passing test does + * not *prove* there aren't padding bits. + */ +_Static_assert(__CHAR_BIT__ == 8, ""); +_Static_assert(sizeof(signed char) == 1, ""); + +#define TEST(Bit, Expected) __builtin_bit_cast(signed char, (unsigned char)(1 << Bit)) == Expected +_Static_assert(TEST(0, 1), ""); +_Static_assert(TEST(1, 2), ""); +_Static_assert(TEST(2, 4), ""); +_Static_assert(TEST(3, 8), ""); +_Static_assert(TEST(4, 16), ""); +_Static_assert(TEST(5, 32), ""); +_Static_assert(TEST(6, 64), ""); +_Static_assert(TEST(7, (signed char)128), ""); + diff --git a/clang/www/c_status.html b/clang/www/c_status.html index 9e4600b3e66acb..b1f5ab4cbc4f07 100644 --- a/clang/www/c_status.html +++ b/clang/www/c_status.html @@ -411,7 +411,7 @@ <h2 id="c11">C11 implementation status</h2> <tr> <td>Requiring signed char to have no padding bits</td> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1310.htm">N1310</a></td> - <td class="unknown" align="center">Unknown</td> + <td class="full" align="center">Yes</td> </tr> <tr> <td>Initializing static or external variables</td> _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits