llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Aaron Ballman (AaronBallman) <details> <summary>Changes</summary> WG14 N3353 added support for 0o and 0O as octal literal prefixes. It also deprecates use of octal literals without a prefix, except for the literal 0. This feature is being exposed as an extension in older C language modes as well as in all C++ language modes. --- Full diff: https://github.com/llvm/llvm-project/pull/131626.diff 7 Files Affected: - (modified) clang/docs/LanguageExtensions.rst (+1) - (modified) clang/docs/ReleaseNotes.rst (+4) - (modified) clang/include/clang/Basic/DiagnosticGroups.td (+3-1) - (modified) clang/include/clang/Basic/DiagnosticLexKinds.td (+8) - (modified) clang/lib/Lex/LiteralSupport.cpp (+22) - (added) clang/test/C/C2y/n3353.c (+95) - (modified) clang/www/c_status.html (+1-1) ``````````diff diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst index cc12ff5bad353..a96816916b5f2 100644 --- a/clang/docs/LanguageExtensions.rst +++ b/clang/docs/LanguageExtensions.rst @@ -1652,6 +1652,7 @@ Designated initializers (N494) C Array & element qualification (N2607) C23 C89 Attributes (N2335) C23 C89 ``#embed`` (N3017) C23 C89, C++ +Octal literals prefixed with ``0o`` or ``0O`` C2y C89, C++ ============================================= ================================ ============= ============= Builtin type aliases diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 2a1c5ee2d788e..bfb6235247709 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -120,6 +120,10 @@ C2y Feature Support - Implemented `WG14 N3411 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3411.pdf>`_ which allows a source file to not end with a newline character. This is still reported as a conforming extension in earlier language modes. +- Implemented `WG14 N3353 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3353.htm>_` + which adds the new ``0o`` and ``0O`` ocal literal prefixes and deprecates + octal literals other than ``0`` which do not start with the new prefix. This + feature is exposed in earlier language modes and in C++ as an extension. C23 Feature Support ^^^^^^^^^^^^^^^^^^^ diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td index fac80fb4009aa..e386d8f2c3b27 100644 --- a/clang/include/clang/Basic/DiagnosticGroups.td +++ b/clang/include/clang/Basic/DiagnosticGroups.td @@ -92,6 +92,7 @@ def EnumCompare : DiagGroup<"enum-compare", [EnumCompareSwitch, def DeprecatedAnonEnumEnumConversion : DiagGroup<"deprecated-anon-enum-enum-conversion">; def DeprecatedEnumEnumConversion : DiagGroup<"deprecated-enum-enum-conversion">; def DeprecatedEnumFloatConversion : DiagGroup<"deprecated-enum-float-conversion">; +def DeprecatedOctalLiterals : DiagGroup<"deprecated-octal-literals">; def AnonEnumEnumConversion : DiagGroup<"anon-enum-enum-conversion", [DeprecatedAnonEnumEnumConversion]>; def EnumEnumConversion : DiagGroup<"enum-enum-conversion", @@ -235,7 +236,8 @@ def Deprecated : DiagGroup<"deprecated", [DeprecatedAnonEnumEnumConversion, DeprecatedVolatile, DeprecatedWritableStr, DeprecatedRedundantConstexprStaticDef, - DeprecatedMissingCommaVariadicParam + DeprecatedMissingCommaVariadicParam, + DeprecatedOctalLiterals ]>, DiagCategory<"Deprecations">; diff --git a/clang/include/clang/Basic/DiagnosticLexKinds.td b/clang/include/clang/Basic/DiagnosticLexKinds.td index 0e5592d65669b..f662ad1211ba3 100644 --- a/clang/include/clang/Basic/DiagnosticLexKinds.td +++ b/clang/include/clang/Basic/DiagnosticLexKinds.td @@ -256,6 +256,14 @@ def warn_cxx17_hex_literal : Warning< "hexadecimal floating literals are incompatible with " "C++ standards before C++17">, InGroup<CXXPre17CompatPedantic>, DefaultIgnore; +def ext_octal_literal : Extension< + "octal integer literals are a C2y extension">, InGroup<C2y>; +def warn_c2y_compat_octal_literal : Warning< + "octal integer literals are incompatible with standards before C2y">, + InGroup<CPre2yCompat>, DefaultIgnore; +def warn_unprefixed_octal_deprecated : Warning< + "octal literals without a '0o' prefix are deprecated">, + InGroup<DeprecatedOctalLiterals>; def ext_binary_literal : Extension< "binary integer literals are a C23 extension">, InGroup<C23>; def warn_c23_compat_binary_literal : Warning< diff --git a/clang/lib/Lex/LiteralSupport.cpp b/clang/lib/Lex/LiteralSupport.cpp index 69dc057d0df4b..0ab27b2d40373 100644 --- a/clang/lib/Lex/LiteralSupport.cpp +++ b/clang/lib/Lex/LiteralSupport.cpp @@ -21,6 +21,7 @@ #include "clang/Lex/Preprocessor.h" #include "clang/Lex/Token.h" #include "llvm/ADT/APInt.h" +#include "llvm/ADT/ScopeExit.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/StringExtras.h" #include "llvm/ADT/StringSwitch.h" @@ -1423,6 +1424,27 @@ void NumericLiteralParser::ParseNumberStartingWithZero(SourceLocation TokLoc) { return; } + // Parse a potential octal literal prefix. + bool SawOctalPrefix = false; + if ((c1 == 'O' || c1 == 'o') && (s[1] >= '0' && s[1] <= '7')) { + unsigned DiagId; + if (LangOpts.C2y) + DiagId = diag::warn_c2y_compat_octal_literal; + else + DiagId = diag::ext_octal_literal; + Diags.Report(TokLoc, DiagId); + ++s; + DigitsBegin = s; + SawOctalPrefix = true; + } + + auto _ = llvm::make_scope_exit([&] { + // If we still have an octal value but we did not see an octal prefix, + // diagnose as being an obsolescent feature starting in C2y. + if (radix == 8 && LangOpts.C2y && !SawOctalPrefix && !hadError) + Diags.Report(TokLoc, diag::warn_unprefixed_octal_deprecated); + }); + // For now, the radix is set to 8. If we discover that we have a // floating point constant, the radix will change to 10. Octal floating // point constants are not permitted (only decimal and hexadecimal). diff --git a/clang/test/C/C2y/n3353.c b/clang/test/C/C2y/n3353.c new file mode 100644 index 0000000000000..4e8b7f0fc43ba --- /dev/null +++ b/clang/test/C/C2y/n3353.c @@ -0,0 +1,95 @@ +// RUN: %clang_cc1 -verify=expected,c2y -pedantic -std=c2y %s +// RUN: %clang_cc1 -verify=expected,c2y,compat -Wpre-c2y-compat -std=c2y %s +// RUN: %clang_cc1 -verify=expected,ext -pedantic -std=c23 %s +// RUN: %clang_cc1 -verify=expected,ext -pedantic -x c++ -Wno-c11-extensions %s + + +/* WG14 N3353: Clang 21 + * Obsolete implicitly octal literals and add delimited escape sequences + */ + +constexpr int i = 0234; // c2y-warning {{octal literals without a '0o' prefix are deprecated}} +constexpr int j = 0o234; /* ext-warning {{octal integer literals are a C2y extension}} + compat-warning {{octal integer literals are incompatible with standards before C2y}} + */ + +static_assert(i == 156); +static_assert(j == 156); + +// Show that 0O is the same as Oo (tested above) +static_assert(0O1234 == 0o1234); /* ext-warning 2 {{octal integer literals are a C2y extension}} + compat-warning 2 {{octal integer literals are incompatible with standards before C2y}} + */ + +// Demonstrate that it works fine in the preprocessor. +#if 0o123 != 0x53 /* ext-warning {{octal integer literals are a C2y extension}} + compat-warning {{octal integer literals are incompatible with standards before C2y}} + */ +#error "oh no, math stopped working!" +#endif + +// 0 by itself is not deprecated, of course. +int k = 0; + +// Make sure there are no surprises with auto and type deduction. Promotion +// turns this into an 'int', and 'constexpr' implies 'const'. +constexpr auto l = 0o1234567; /* ext-warning {{octal integer literals are a C2y extension}} + compat-warning {{octal integer literals are incompatible with standards before C2y}} + */ +static_assert(l == 0x53977); +static_assert(__extension__ _Generic(typeof(0o1), typeof(01) : 1, default : 0)); /* c2y-warning {{octal literals without a '0o' prefix are deprecated}} + compat-warning {{passing a type argument as the first operand to '_Generic' is incompatible with C standards before C2y}} + compat-warning {{octal integer literals are incompatible with standards before C2y}} + */ +static_assert(__extension__ _Generic(typeof(l), const int : 1, default : 0)); // compat-warning {{passing a type argument as the first operand to '_Generic' is incompatible with C standards before C2y}} + +// Note that 0o by itself is an invalid literal. +int m = 0o; /* expected-error {{invalid suffix 'o' on integer constant}} + c2y-warning {{octal literals without a '0o' prefix are deprecated}} + */ + +// Ensure negation works as expected. +static_assert(-0o1234 == -668); /* ext-warning {{octal integer literals are a C2y extension}} + compat-warning {{octal integer literals are incompatible with standards before C2y}} + */ + +// FIXME: it would be better to not diagnose the compat and ext warnings when +// the octal literal is invalid. +// We expect diagnostics for non-octal digits. +int n = 0o18; /* expected-error {{invalid digit '8' in octal constant}} + compat-warning {{octal integer literals are incompatible with standards before C2y}} + ext-warning {{octal integer literals are a C2y extension}} + */ +int o1 = 0o8; /* expected-error {{invalid suffix 'o8' on integer constant}} + c2y-warning {{octal literals without a '0o' prefix are deprecated}} + */ +// FIXME: however, it matches the behavior for hex literals in terms of the +// error reported. Unfortunately, we then go on to think 0 is an octal literal +// without a prefix, which is again a bit confusing. +int o2 = 0xG; /* expected-error {{invalid suffix 'xG' on integer constant}} + c2y-warning {{octal literals without a '0o' prefix are deprecated}} + */ + +// Ensure digit separators work as expected. +constexpr int p = 0o0'1'2'3'4'5'6'7; /* compat-warning {{octal integer literals are incompatible with standards before C2y}} + ext-warning {{octal integer literals are a C2y extension}} + */ +static_assert(p == 01234567); // c2y-warning {{octal literals without a '0o' prefix are deprecated}} +int q = 0o'0'1; /* expected-error {{invalid suffix 'o'0'1' on integer constant}} + c2y-warning {{octal literals without a '0o' prefix are deprecated}} + */ + +#ifdef __cplusplus +template <unsigned N> +struct S { + static_assert(N == 0o567); /* ext-warning {{octal integer literals are a C2y extension}} + compat-warning {{octal integer literals are incompatible with standards before C2y}} + */ +}; + +void foo() { + S<0o567> s; /* ext-warning {{octal integer literals are a C2y extension}} + compat-warning {{octal integer literals are incompatible with standards before C2y}} + */ +} +#endif diff --git a/clang/www/c_status.html b/clang/www/c_status.html index d68e8d6441ed2..7cf50bfdb6639 100644 --- a/clang/www/c_status.html +++ b/clang/www/c_status.html @@ -176,7 +176,7 @@ <h2 id="c2y">C2y implementation status</h2> <tr> <td>Obsolete implicitly octal literals and add delimited escape sequences</td> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3353.htm";>N3353</a></td> - <td class="none" align="center">No</td> + <td class="unreleased" align="center">Clang 21</td> </tr> <tr> <td>'if' declarations, v2</td> `````````` </details> https://github.com/llvm/llvm-project/pull/131626 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
