Author: Aaron Ballman Date: 2024-11-08T12:43:19-05:00 New Revision: c3c2f46f7bd5891af13fef56a8754007f11ff6c1
URL: https://github.com/llvm/llvm-project/commit/c3c2f46f7bd5891af13fef56a8754007f11ff6c1 DIFF: https://github.com/llvm/llvm-project/commit/c3c2f46f7bd5891af13fef56a8754007f11ff6c1.diff LOG: [C2y] Claim conformance and add test coverage for WG14 N3346 (#115516) This converts some undefined behaviors during initialization to instead be constraint violations. Clang has always implemented these as constraints, so no compiler changes were needed. Added: clang/test/C/C2y/n3346.c Modified: clang/docs/ReleaseNotes.rst clang/www/c_status.html Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index d4bf05651a63eb..77ba5f1d79bcdb 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -303,6 +303,11 @@ C2y Feature Support undefined. Clang has always accepted ``const`` and ``volatile`` qualified function types by ignoring the qualifiers. +- Updated conformance for `N3346 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3346.pdf>`_ + which changes some undefined behavior around initialization to instead be + constraint violations. This paper adopts Clang's existing practice, so there + were no changes to compiler behavior. + C23 Feature Support ^^^^^^^^^^^^^^^^^^^ diff --git a/clang/test/C/C2y/n3346.c b/clang/test/C/C2y/n3346.c new file mode 100644 index 00000000000000..2f0ef51d56fb76 --- /dev/null +++ b/clang/test/C/C2y/n3346.c @@ -0,0 +1,68 @@ +// RUN: %clang_cc1 -verify -std=c2y -Wall -pedantic -ffreestanding %s +// RUN: %clang_cc1 -verify=expected,ped -Wall -pedantic -ffreestanding %s + +/* WG14 N3346: Yes + * Slay Some Earthly Demons VIII + * + * Updates some undefined behavior during initialization to instead be a + * constraint violation. + */ + +// The initializer for a scalar shall be a single expression, optionally +// enclosed in braces, or it shall be an empty initializer. +int i = 12, j = {12}, k = {}; // ped-warning {{use of an empty initializer is a C23 extension}} + +struct S { + int i; + float f; + int : 0; + char c; +}; + +void test1(void) { + // The initializer for an object that has structure or union type shall be + // either a single expression that has compatible type or a brace-enclosed + // list of initializers for the elements or named members. + struct S s1 = { 1, 1.2f, 'a' }; + struct S s2 = s1; + + // Despite being structurally identical to S, T is not compatible with S. + struct T { int i; float f; int : 0; char c; } t; + struct S s3 = t; // expected-error {{initializing 'struct S' with an expression of incompatible type 'struct T'}} +} + +void test2(void) { + typedef __WCHAR_TYPE__ wchar_t; + typedef __CHAR16_TYPE__ char16_t; + typedef __CHAR32_TYPE__ char32_t; + + // The initializer for an array shall be either a string literal, optionally + // enclosed in braces, or a brace-enclosed list of initializers for the + // elements. An array initialized by character string literal or UTF-8 string + // literal shall have a character type as element type. An array initialized + // with a wide string literal shall have element type compatible with a + // qualified or unqualified wchar_t, char16_t, or char32_t, and the string + // literal shall have the corresponding encoding prefix (L, u, or U, + // respectively). + char str1[] = "string literal"; + char str2[] = { "string literal" }; + char str3[] = u8"string literal"; + char str4[] = { u8"string literal" }; + + int str5[] = "this doesn't work"; // expected-error {{array initializer must be an initializer list}} + int str6[] = { "this also doesn't work" }; // expected-error {{incompatible pointer to integer conversion initializing 'int' with an expression of type 'char[23]'}} + + wchar_t str7[] = L"string literal"; + wchar_t str8[] = { L"string literal" }; + char16_t str9[] = u"string literal"; + char16_t str10[] = { u"string literal" }; + char32_t str11[] = U"string literal"; + char32_t str12[] = { U"string literal" }; + + wchar_t str13[] = "nope"; // expected-error {{initializing wide char array with non-wide string literal}} + wchar_t str14[] = { "nope" }; // expected-error-re {{incompatible pointer to integer conversion initializing 'wchar_t' (aka '{{.*}}') with an expression of type 'char[5]'}} + char16_t str15[] = "nope"; // expected-error {{initializing wide char array with non-wide string literal}} + char16_t str16[] = { "nope" }; // expected-error-re {{incompatible pointer to integer conversion initializing 'char16_t' (aka '{{.*}}') with an expression of type 'char[5]'}} + char32_t str17[] = "nope"; // expected-error {{initializing wide char array with non-wide string literal}} + char32_t str18[] = { "nope" }; // expected-error-re {{incompatible pointer to integer conversion initializing 'char32_t' (aka '{{.*}}') with an expression of type 'char[5]'}} +} diff --git a/clang/www/c_status.html b/clang/www/c_status.html index fa2411e674d768..663cc2e33f5157 100644 --- a/clang/www/c_status.html +++ b/clang/www/c_status.html @@ -211,7 +211,7 @@ <h2 id="c2y">C2y implementation status</h2> <tr> <td>Slay Some Earthly Demons VIII</td> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3346.pdf";>N3346</a></td> - <td class="unknown" align="center">Unknown</td> + <td class="full" align="center">Yes</td> </tr> <tr> <td>Introduce complex literals v. 2</td> _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
