Author: Aaron Ballman Date: 2024-01-21T13:20:56-05:00 New Revision: 997ffce43c6d2d3f647eb091c732665049b1f47f
URL: https://github.com/llvm/llvm-project/commit/997ffce43c6d2d3f647eb091c732665049b1f47f DIFF: https://github.com/llvm/llvm-project/commit/997ffce43c6d2d3f647eb091c732665049b1f47f.diff LOG: [C23] Implement N2490, Remove trigraphs??! This follows the same implementation logic as with C++ and is compatible with the GCC behavior in C. Trigraphs are enabled by default in -std=c* conformance modes before C23, but are disabled in GNU and Microsoft modes as well as in C23 or later. Added: clang/test/C/C2x/n2940.c Modified: clang/docs/ReleaseNotes.rst clang/lib/Frontend/CompilerInvocation.cpp clang/test/C/drs/dr3xx.c clang/test/Preprocessor/ucn-pp-identifier.c clang/www/c_status.html Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 8bb26fcae18d6b6..28fd79abbe782a4 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -271,6 +271,13 @@ C23 Feature Support previously implemented allowing a label at the end of a compound statement, and now we've implemented allowing a label to be followed by a declaration instead of a statement. +- Implemented + `N2940 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2940.pdf>`_ which + removes support for trigraphs in C23 and later. In earlier language modes, + trigraphs remain enabled by default in conforming modes (e.g. ``-std=c17``) + and disabled by default in GNU and Microsoft modes (e.g., ``-std=gnu17`` or + ``-fms-compatibility``). If needed, you can enable trigraphs by passing + ``-ftrigraphs``. Non-comprehensive list of changes in this release ------------------------------------------------- diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index ed9cd1299eae282..7edea7798af1ef0 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -3480,7 +3480,8 @@ void CompilerInvocationBase::GenerateLangArgs(const LangOptions &Opts, Twine(Major) + "." + Twine(Minor) + "." + Twine(Subminor)); } - if ((!Opts.GNUMode && !Opts.MSVCCompat && !Opts.CPlusPlus17) || T.isOSzOS()) { + if ((!Opts.GNUMode && !Opts.MSVCCompat && !Opts.CPlusPlus17 && !Opts.C23) || + T.isOSzOS()) { if (!Opts.Trigraphs) GenerateArg(Consumer, OPT_fno_trigraphs); } else { @@ -3876,10 +3877,11 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args, // Mimicking gcc's behavior, trigraphs are only enabled if -trigraphs // is specified, or -std is set to a conforming mode. - // Trigraphs are disabled by default in c++1z onwards. + // Trigraphs are disabled by default in C++17 and C23 onwards. // For z/OS, trigraphs are enabled by default (without regard to the above). Opts.Trigraphs = - (!Opts.GNUMode && !Opts.MSVCCompat && !Opts.CPlusPlus17) || T.isOSzOS(); + (!Opts.GNUMode && !Opts.MSVCCompat && !Opts.CPlusPlus17 && !Opts.C23) || + T.isOSzOS(); Opts.Trigraphs = Args.hasFlag(OPT_ftrigraphs, OPT_fno_trigraphs, Opts.Trigraphs); diff --git a/clang/test/C/C2x/n2940.c b/clang/test/C/C2x/n2940.c new file mode 100644 index 000000000000000..ee92b6ec94a8c7c --- /dev/null +++ b/clang/test/C/C2x/n2940.c @@ -0,0 +1,26 @@ +// RUN: %clang_cc1 -verify=no-trigraphs -std=c23 %s +// RUN: %clang_cc1 -verify=no-trigraphs -std=gnu23 %s +// RUN: %clang_cc1 -verify=no-trigraphs -std=gnu17 %s +// RUN: %clang_cc1 -verify=no-trigraphs -std=gnu11 %s +// RUN: %clang_cc1 -verify=no-trigraphs -std=gnu99 %s +// RUN: %clang_cc1 -verify=no-trigraphs -std=gnu89 %s +// RUN: %clang_cc1 -verify=trigraphs -std=c17 %s +// RUN: %clang_cc1 -verify=trigraphs -std=c11 %s +// RUN: %clang_cc1 -verify=trigraphs -std=c99 %s +// RUN: %clang_cc1 -verify=trigraphs -std=c89 %s +// RUN: %clang_cc1 -verify=trigraphs -std=c23 -ftrigraphs %s + +/* WG14 N2940: Clang 18 + * Removing trigraphs??! + */ + +// Trigraphs are enabled by default in any conforming C mode before C23, but +// are otherwise disabled (in all GNU modes, and in C23 or later). +// The ??= trigraph, if supported, will become the # character, which is a null +// preprocessor directive that does nothing. + +??= +// no-trigraphs-warning@-1 {{trigraph ignored}} \ + no-trigraphs-error@-1 {{expected identifier or '('}} \ + trigraphs-warning@-1 {{trigraph converted to '#' character}} + diff --git a/clang/test/C/drs/dr3xx.c b/clang/test/C/drs/dr3xx.c index 4d6617184d9a4be..0f67470b013a5d0 100644 --- a/clang/test/C/drs/dr3xx.c +++ b/clang/test/C/drs/dr3xx.c @@ -1,8 +1,8 @@ -/* RUN: %clang_cc1 -std=c89 -fsyntax-only -Wvla -verify=expected,c89only -pedantic -Wno-c11-extensions %s - RUN: %clang_cc1 -std=c99 -fsyntax-only -Wvla -verify=expected,c99andup -pedantic -Wno-c11-extensions %s - RUN: %clang_cc1 -std=c11 -fsyntax-only -Wvla -verify=expected,c99andup -pedantic %s - RUN: %clang_cc1 -std=c17 -fsyntax-only -Wvla -verify=expected,c99andup -pedantic %s - RUN: %clang_cc1 -std=c2x -fsyntax-only -Wvla -verify=expected,c99andup -pedantic %s +/* RUN: %clang_cc1 -std=c89 -fsyntax-only -Wvla -verify=expected,c89only,c17andearlier -pedantic -Wno-c11-extensions %s + RUN: %clang_cc1 -std=c99 -fsyntax-only -Wvla -verify=expected,c99andup,c17andearlier -pedantic -Wno-c11-extensions %s + RUN: %clang_cc1 -std=c11 -fsyntax-only -Wvla -verify=expected,c99andup,c17andearlier -pedantic %s + RUN: %clang_cc1 -std=c17 -fsyntax-only -Wvla -verify=expected,c99andup,c17andearlier -pedantic %s + RUN: %clang_cc1 -std=c2x -fsyntax-only -Wvla -verify=expected,c99andup,c23andup -pedantic %s */ /* The following are DRs which do not require tests to demonstrate @@ -70,13 +70,6 @@ #error "We definitely should not have gotten here" #endif -/* WG14 DR309: yes - * Clarifying trigraph substitution - */ -int dr309??(1??) = { 1 }; /* expected-warning {{trigraph converted to '[' character}} - expected-warning {{trigraph converted to ']' character}} - */ - /* WG14 DR311: yes * Definition of variably modified types */ @@ -292,3 +285,17 @@ void f(long double f, char (**a)[10 * sizeof f]) { _Static_assert(sizeof **a == sizeof(long double) * 10, ""); } + +/* WG14 DR309: yes + * Clarifying trigraph substitution + */ +int dr309??(1??) = { 1 }; /* c17andearlier-warning {{trigraph converted to '[' character}} + c17andearlier-warning {{trigraph converted to ']' character}} + c23andup-warning 2 {{trigraph ignored}} + c23andup-error {{expected ';' after top level declarator}} + */ + +/* NOTE: Due to interactions with the diagnostic system, dr309 should be the + * last test case in this file because subsequent diagnostics may not be + * generated as expected. + */ diff --git a/clang/test/Preprocessor/ucn-pp-identifier.c b/clang/test/Preprocessor/ucn-pp-identifier.c index 19cfc2589efddb7..5efcfe48f638ab4 100644 --- a/clang/test/Preprocessor/ucn-pp-identifier.c +++ b/clang/test/Preprocessor/ucn-pp-identifier.c @@ -1,5 +1,5 @@ // RUN: %clang_cc1 %s -fsyntax-only -std=c99 -pedantic -verify=expected,ext -Wundef -DTRIGRAPHS=1 -// RUN: %clang_cc1 %s -fsyntax-only -std=c2x -pedantic -verify=expected,ext -Wundef -DTRIGRAPHS=1 +// RUN: %clang_cc1 %s -fsyntax-only -std=c23 -pedantic -verify=expected,ext -Wundef -ftrigraphs -DTRIGRAPHS=1 // RUN: %clang_cc1 %s -fsyntax-only -x c++ -pedantic -verify=expected,ext -Wundef -fno-trigraphs // RUN: %clang_cc1 %s -fsyntax-only -x c++ -std=c++23 -pedantic -ftrigraphs -DTRIGRAPHS=1 -verify=expected,cxx23 -Wundef -Wpre-c++23-compat // RUN: %clang_cc1 %s -fsyntax-only -x c++ -pedantic -verify=expected,ext -Wundef -ftrigraphs -DTRIGRAPHS=1 diff --git a/clang/www/c_status.html b/clang/www/c_status.html index b9e0650ddca2429..3955a1d79639764 100644 --- a/clang/www/c_status.html +++ b/clang/www/c_status.html @@ -1156,7 +1156,7 @@ <h2 id="c2x">C23 implementation status</h2> <tr> <td>Remove trigraphs??!</td> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2940.pdf";>N2940</a></td> - <td class="full" align="center">Yes</td> + <td class="unreleased" align="center">Clang 18</td> </tr> <tr> <td>Improved normal enumerations</td> _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
