Author: Mariya Podchishchaeva Date: 2024-09-13T11:11:34+02:00 New Revision: a0f88901a4e6a6618c3ec02108103d0415e28834
URL: https://github.com/llvm/llvm-project/commit/a0f88901a4e6a6618c3ec02108103d0415e28834 DIFF: https://github.com/llvm/llvm-project/commit/a0f88901a4e6a6618c3ec02108103d0415e28834.diff LOG: [clang][C23] Support N3029 Improved Normal Enumerations (#103917) Basically clang already implemented 90% of the feature as an extension. This commit disables warnings for C23 and aligns types of enumerators according to the recent wording. Added: clang/test/C/C23/n3029.c Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Basic/DiagnosticSemaKinds.td clang/lib/Sema/SemaDecl.cpp clang/test/Misc/warning-flags.c clang/test/Sema/enum.c clang/www/c_status.html Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index c4fa017b982bbd..3929a9fb599259 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -179,6 +179,8 @@ C2y Feature Support C23 Feature Support ^^^^^^^^^^^^^^^^^^^ +- Clang now supports `N3029 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3029.htm>`_ Improved Normal Enumerations. + Non-comprehensive list of changes in this release ------------------------------------------------- diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index efdc058edca56d..3a465464bc5b47 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -1039,7 +1039,6 @@ def err_opencl_invalid_param : Error< "declaring function parameter of type %0 is not allowed%select{; did you forget * ?|}1">; def err_opencl_invalid_return : Error< "declaring function return value of type %0 is not allowed %select{; did you forget * ?|}1">; -def warn_enum_value_overflow : Warning<"overflow in enumeration value">; def warn_pragma_options_align_reset_failed : Warning< "#pragma options align=reset failed: %0">, InGroup<IgnoredPragmas>; @@ -6194,9 +6193,13 @@ def err_misplaced_ivar : Error< def warn_ivars_in_interface : Warning< "declaration of instance variables in the interface is deprecated">, InGroup<DiagGroup<"objc-interface-ivars">>, DefaultIgnore; -def ext_enum_value_not_int : Extension< - "ISO C restricts enumerator values to range of 'int' (%0 is too " - "%select{small|large}1)">; +def ext_c23_enum_value_not_int : Extension< + "%select{|incremented }0enumerator value which exceeds the range of 'int' is " + "a C23 extension (%1 is too %select{small|large}2)">, InGroup<C23>; +def warn_c17_compat_enum_value_not_int : Warning< + "%select{|incremented }0enumerator value which exceeds the range of 'int' is " + "incompatible with C standards before C23 (%1 is too %select{small|large}2)">, + DefaultIgnore, InGroup<CPre23Compat>; def ext_enum_too_large : ExtWarn< "enumeration values exceed range of largest integer">, InGroup<EnumTooLarge>; def ext_enumerator_increment_too_large : ExtWarn< diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp index 3c6a0dff798ff6..8557c25b93a8da 100644 --- a/clang/lib/Sema/SemaDecl.cpp +++ b/clang/lib/Sema/SemaDecl.cpp @@ -19479,11 +19479,13 @@ EnumConstantDecl *Sema::CheckEnumConstant(EnumDecl *Enum, // representable as an int. // Complain if the value is not representable in an int. - if (!isRepresentableIntegerValue(Context, EnumVal, Context.IntTy)) - Diag(IdLoc, diag::ext_enum_value_not_int) - << toString(EnumVal, 10) << Val->getSourceRange() - << (EnumVal.isUnsigned() || EnumVal.isNonNegative()); - else if (!Context.hasSameType(Val->getType(), Context.IntTy)) { + if (!isRepresentableIntegerValue(Context, EnumVal, Context.IntTy)) { + Diag(IdLoc, getLangOpts().C23 + ? diag::warn_c17_compat_enum_value_not_int + : diag::ext_c23_enum_value_not_int) + << 0 << toString(EnumVal, 10) << Val->getSourceRange() + << (EnumVal.isUnsigned() || EnumVal.isNonNegative()); + } else if (!Context.hasSameType(Val->getType(), Context.IntTy)) { // Force the type of the expression to 'int'. Val = ImpCastExprToType(Val, Context.IntTy, CK_IntegralCast).get(); } @@ -19558,17 +19560,22 @@ EnumConstantDecl *Sema::CheckEnumConstant(EnumDecl *Enum, // If we're not in C++, diagnose the overflow of enumerator values, // which in C99 means that the enumerator value is not representable in - // an int (C99 6.7.2.2p2). However, we support GCC's extension that - // permits enumerator values that are representable in some larger - // integral type. - if (!getLangOpts().CPlusPlus && !T.isNull()) - Diag(IdLoc, diag::warn_enum_value_overflow); - } else if (!getLangOpts().CPlusPlus && - !EltTy->isDependentType() && + // an int (C99 6.7.2.2p2). However C23 permits enumerator values that + // are representable in some larger integral type and we allow it in + // older language modes as an extension. + // Exclude fixed enumerators since they are diagnosed with an error for + // this case. + if (!getLangOpts().CPlusPlus && !T.isNull() && !Enum->isFixed()) + Diag(IdLoc, getLangOpts().C23 + ? diag::warn_c17_compat_enum_value_not_int + : diag::ext_c23_enum_value_not_int) + << 1 << toString(EnumVal, 10) << 1; + } else if (!getLangOpts().CPlusPlus && !EltTy->isDependentType() && !isRepresentableIntegerValue(Context, EnumVal, EltTy)) { // Enforce C99 6.7.2.2p2 even when we compute the next value. - Diag(IdLoc, diag::ext_enum_value_not_int) - << toString(EnumVal, 10) << 1; + Diag(IdLoc, getLangOpts().C23 ? diag::warn_c17_compat_enum_value_not_int + : diag::ext_c23_enum_value_not_int) + << 1 << toString(EnumVal, 10) << 1; } } } @@ -19887,9 +19894,6 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange, return; } - // TODO: If the result value doesn't fit in an int, it must be a long or long - // long value. ISO C does not support this, but GCC does as an extension, - // emit a warning. unsigned IntWidth = Context.getTargetInfo().getIntWidth(); unsigned CharWidth = Context.getTargetInfo().getCharWidth(); unsigned ShortWidth = Context.getTargetInfo().getShortWidth(); @@ -19898,13 +19902,14 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange, // reverse the list. unsigned NumNegativeBits = 0; unsigned NumPositiveBits = 0; + bool MembersRepresentableByInt = true; for (unsigned i = 0, e = Elements.size(); i != e; ++i) { EnumConstantDecl *ECD = cast_or_null<EnumConstantDecl>(Elements[i]); if (!ECD) continue; // Already issued a diagnostic. - const llvm::APSInt &InitVal = ECD->getInitVal(); + llvm::APSInt InitVal = ECD->getInitVal(); // Keep track of the size of positive and negative values. if (InitVal.isUnsigned() || InitVal.isNonNegative()) { @@ -19916,6 +19921,8 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange, NumNegativeBits = std::max(NumNegativeBits, (unsigned)InitVal.getSignificantBits()); } + MembersRepresentableByInt &= + isRepresentableIntegerValue(Context, InitVal, Context.IntTy); } // If we have an empty set of enumerators we still need one bit. @@ -19937,7 +19944,7 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange, // int, long long int, or unsigned long long int. // C99 6.4.4.3p2: // An identifier declared as an enumeration constant has type int. - // The C99 rule is modified by a gcc extension + // The C99 rule is modified by C23. QualType BestPromotionType; bool Packed = Enum->hasAttr<PackedAttr>(); @@ -20031,7 +20038,7 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange, auto *ECD = cast_or_null<EnumConstantDecl>(D); if (!ECD) continue; // Already issued a diagnostic. - // Standard C says the enumerators have int type, but we allow, as an + // C99 says the enumerators have int type, but we allow, as an // extension, the enumerators to be larger than int size. If each // enumerator value fits in an int, type it as an int, otherwise type it the // same as the enumerator decl itself. This means that in "enum { X = 1U }" @@ -20045,9 +20052,14 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange, QualType NewTy; unsigned NewWidth; bool NewSign; - if (!getLangOpts().CPlusPlus && - !Enum->isFixed() && - isRepresentableIntegerValue(Context, InitVal, Context.IntTy)) { + if (!getLangOpts().CPlusPlus && !Enum->isFixed() && + MembersRepresentableByInt) { + // C23 6.7.3.3.3p15: + // The enumeration member type for an enumerated type without fixed + // underlying type upon completion is: + // - int if all the values of the enumeration are representable as an + // int; or, + // - the enumerated type NewTy = Context.IntTy; NewWidth = IntWidth; NewSign = true; diff --git a/clang/test/C/C23/n3029.c b/clang/test/C/C23/n3029.c new file mode 100644 index 00000000000000..26d6dfdcc60462 --- /dev/null +++ b/clang/test/C/C23/n3029.c @@ -0,0 +1,65 @@ +// RUN: %clang_cc1 -verify=expected,all -triple x86_64-unknown-linux-gnu -fsyntax-only -std=c23 %s -Wpre-c23-compat +// RUN: %clang_cc1 -verify=pedantic,all -triple x86_64-unknown-linux-gnu -fsyntax-only -std=c17 %s -pedantic + +#include <limits.h> + +#define GET_TYPE_INT(x) _Generic(x, \ + char: 1,\ + unsigned char: 2,\ + signed char: 3,\ + short: 4,\ + unsigned short: 5,\ + int: 6,\ + unsigned int: 7,\ + long: 8,\ + unsigned long: 9,\ + long long: 10,\ + unsigned long long: 11,\ + default: 0xFF\ + )\ + +enum x { +a = INT_MAX, +b = ULLONG_MAX, // expected-warning {{enumerator value which exceeds the range of 'int' is incompatible with C standards before C23}} + // pedantic-warning@-1 {{enumerator value which exceeds the range of 'int' is a C23 extension}} +a_type = GET_TYPE_INT(a), +b_type = GET_TYPE_INT(b) +}; + +_Static_assert(GET_TYPE_INT(a) == GET_TYPE_INT(b), "ok"); + +extern enum x e_a; +extern __typeof(b) e_a; +extern __typeof(a) e_a; + +enum a { + a0 = 0xFFFFFFFFFFFFFFFFULL // expected-warning {{enumerator value which exceeds the range of 'int' is incompatible with C standards before C23}} + // pedantic-warning@-1 {{enumerator value which exceeds the range of 'int' is a C23 extension}} +}; + +_Bool e (void) { + return a0; +} + +int f (void) { + return a0; // all-warning {{implicit conversion from 'unsigned long' to 'int' changes value from 18446744073709551615 to -1}} +} + +unsigned long g (void) { + return a0; +} + +unsigned long long h (void) { + return a0; +} + +enum big_enum { + big_enum_a = LONG_MAX, // expected-warning {{enumerator value which exceeds the range of 'int' is incompatible with C standards before C23}} + // pedantic-warning@-1 {{enumerator value which exceeds the range of 'int' is a C23 extension}} + big_enum_b = a + 1, // expected-warning {{enumerator value which exceeds the range of 'int' is incompatible with C standards before C23}} + // pedantic-warning@-1 {{enumerator value which exceeds the range of 'int' is a C23 extension}} + big_enum_c = ULLONG_MAX // expected-warning {{enumerator value which exceeds the range of 'int' is incompatible with C standards before C23}} + // pedantic-warning@-1 {{enumerator value which exceeds the range of 'int' is a C23 extension}} +}; + +_Static_assert(GET_TYPE_INT(big_enum_a) == GET_TYPE_INT(big_enum_b), "ok"); diff --git a/clang/test/Misc/warning-flags.c b/clang/test/Misc/warning-flags.c index e4e16f074cef33..80c01099140f79 100644 --- a/clang/test/Misc/warning-flags.c +++ b/clang/test/Misc/warning-flags.c @@ -18,7 +18,7 @@ This test serves two purposes: The list of warnings below should NEVER grow. It should gradually shrink to 0. -CHECK: Warnings without flags (63): +CHECK: Warnings without flags (62): CHECK-NEXT: ext_expected_semi_decl_list CHECK-NEXT: ext_missing_whitespace_after_macro_name @@ -46,7 +46,6 @@ CHECK-NEXT: warn_drv_amdgpu_cov6 CHECK-NEXT: warn_drv_assuming_mfloat_abi_is CHECK-NEXT: warn_drv_clang_unsupported CHECK-NEXT: warn_drv_pch_not_first_include -CHECK-NEXT: warn_enum_value_overflow CHECK-NEXT: warn_expected_qualified_after_typename CHECK-NEXT: warn_fe_backend_unsupported CHECK-NEXT: warn_fe_cc_log_diagnostics_failure @@ -86,4 +85,4 @@ CHECK-NEXT: warn_weak_import The list of warnings in -Wpedantic should NEVER grow. -CHECK: Number in -Wpedantic (not covered by other -W flags): 25 +CHECK: Number in -Wpedantic (not covered by other -W flags): 24 diff --git a/clang/test/Sema/enum.c b/clang/test/Sema/enum.c index b0707914c0d852..4f6d04ba7f9182 100644 --- a/clang/test/Sema/enum.c +++ b/clang/test/Sema/enum.c @@ -1,23 +1,23 @@ -// RUN: %clang_cc1 -triple %itanium_abi_triple %s -fsyntax-only -verify -pedantic -// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -fsyntax-only -std=c23 -verify -pedantic +// RUN: %clang_cc1 -triple %itanium_abi_triple %s -fsyntax-only -verify=expected,pre-c23 -pedantic +// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -fsyntax-only -std=c23 -verify=expected -pedantic enum e {A, - B = 42LL << 32, // expected-warning {{ISO C restricts enumerator values to range of 'int'}} + B = 42LL << 32, // pre-c23-warning {{enumerator value which exceeds the range of 'int' is a C23 extension}} C = -4, D = 12456 }; enum f { a = -2147483648, b = 2147483647 }; // ok. enum g { // too negative - c = -2147483649, // expected-warning {{ISO C restricts enumerator values to range of 'int'}} + c = -2147483649, // pre-c23-warning {{enumerator value which exceeds the range of 'int' is a C23 extension}} d = 2147483647 }; enum h { e = -2147483648, // too pos - f = 2147483648, // expected-warning {{ISO C restricts enumerator values to range of 'int'}} - i = 0xFFFF0000 // expected-warning {{too large}} + f = 2147483648, // pre-c23-warning {{enumerator value which exceeds the range of 'int' is a C23 extension}} + i = 0xFFFF0000 // pre-c23-warning {{too large}} }; // minll maxull enum x // expected-warning {{enumeration values exceed range of largest integer}} -{ y = -9223372036854775807LL-1, // expected-warning {{ISO C restricts enumerator values to range of 'int'}} -z = 9223372036854775808ULL }; // expected-warning {{ISO C restricts enumerator values to range of 'int'}} +{ y = -9223372036854775807LL-1, // pre-c23-warning {{enumerator value which exceeds the range of 'int' is a C23 extension}} +z = 9223372036854775808ULL }; // pre-c23-warning {{enumerator value which exceeds the range of 'int' is a C23 extension}} int test(void) { return sizeof(enum e) ; @@ -169,13 +169,16 @@ enum class GH42372_2 { One }; +enum IncOverflow { + V2 = __INT_MAX__, + V3 // pre-c23-warning {{incremented enumerator value which exceeds the range of 'int' is a C23 extension}} +}; + #if __STDC_VERSION__ >= 202311L // FIXME: GCC picks __uint128_t as the underlying type for the enumeration // value and Clang picks unsigned long long. -// FIXME: Clang does not yet implement WG14 N3029, so the warning about -// restricting enumerator values to 'int' is not correct. enum GH59352 { // expected-warning {{enumeration values exceed range of largest integer}} - BigVal = 66666666666666666666wb // expected-warning {{ISO C restricts enumerator values to range of 'int' (66666666666666666666 is too large)}} + BigVal = 66666666666666666666wb }; _Static_assert(BigVal == 66666666666666666666wb); /* expected-error {{static assertion failed due to requirement 'BigVal == 66666666666666666666wb'}} expected-note {{expression evaluates to '11326434445538011818 == 66666666666666666666'}} @@ -191,4 +194,38 @@ _Static_assert( __uint128_t : 1 ) ); + +#include <limits.h> + +void fooinc23() { + enum E1 { + V1 = INT_MAX + } e1; + + enum E2 { + V2 = INT_MAX, + V3 + } e2; + + enum E3 { + V4 = INT_MAX, + V5 = LONG_MIN + } e3; + + enum E4 { + V6 = 1u, + V7 = 2wb + } e4; + + _Static_assert(_Generic(V1, int : 1)); + _Static_assert(_Generic(V2, int : 0, unsigned int : 1)); + _Static_assert(_Generic(V3, int : 0, unsigned int : 1)); + _Static_assert(_Generic(V4, int : 0, signed long : 1)); + _Static_assert(_Generic(V5, int : 0, signed long : 1)); + _Static_assert(_Generic(V6, int : 1)); + _Static_assert(_Generic(V7, int : 1)); + _Static_assert(_Generic((enum E4){}, unsigned int : 1)); + +} + #endif // __STDC_VERSION__ >= 202311L diff --git a/clang/www/c_status.html b/clang/www/c_status.html index 255690cd6d34e2..6e37dd65ccbdee 100644 --- a/clang/www/c_status.html +++ b/clang/www/c_status.html @@ -687,7 +687,7 @@ <h2 id="c2x">C23 implementation status</h2> <tr> <td>Improved normal enumerations</td> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3029.htm";>N3029</a></td> - <td class="unknown" align="center">Unknown</td> + <td class="unreleased" align="center">Clang 20</td> </tr> <tr> <td>Relax requirements for va_start</td> _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
