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1/* RUN: %clang_cc1 -std=c89 -verify=expected,c89only,pre-c23 -pedantic -Wno-c11-extensions %s2 RUN: %clang_cc1 -std=c99 -verify=expected,pre-c23 -pedantic -Wno-c11-extensions %s3 RUN: %clang_cc1 -std=c11 -verify=expected,pre-c23 -pedantic %s4 RUN: %clang_cc1 -std=c17 -verify=expected,pre-c23 -pedantic %s5 RUN: %clang_cc1 -std=c2x -verify=expected -pedantic %s6 */7 8/* The following are DRs which do not require tests to demonstrate9 * conformance or nonconformance.10 *11 * WG14 DR401: yes12 * "happens before" can not be cyclic13 *14 * WG14 DR402: yes15 * Memory model coherence is not aligned with C++1116 *17 * WG14 DR404: yes18 * Joke fragment remains in a footnote19 *20 * WG14 DR406: yes21 * Visible sequences of side effects are redundant22 *23 * WG14 DR415: yes24 * Missing divide by zero entry in Annex J25 *26 * WG14 DR417: yes27 * Annex J not updated with necessary aligned_alloc entries28 *29 * WG14 DR419: yes30 * Generic Functions31 *32 * WG14 DR420: yes33 * Sytax error in specification of for-statement34 *35 * WG14 DR425: yes36 * No specification for the access to variables with temporary lifetime37 *38 * WG14 DR434: yes39 * Possible defect report: Missing constraint w.r.t. Atomic40 *41 * WG14 DR435: yes42 * Possible defect report: Missing constraint w.r.t. Imaginary43 *44 * WG14 DR436: yes45 * Request for interpretation of C11 6.8.5#646 * Note: This is not really testable because it requires -O1 or higher for LLVM47 * to perform its reachability analysis and -Wunreachable-code only verifies48 * diagnostic behavior, not runtime behavior. Also, both are a matter of QoI as49 * to what they optimize/diagnose. But if someone thinks of a way to test this,50 * we can add a test case for it then.51 *52 * WG14 DR448: yes53 * What are the semantics of a # non-directive?54 *55 * WG14 DR454: yes56 * ATOMIC_VAR_INIT (issues 3 and 4)57 *58 * WG14 DR455: yes59 * ATOMIC_VAR_INIT issue 560 *61 * WG14 DR459: yes62 * atomic_load missing const qualifier63 *64 * WG14 DR475: yes65 * Misleading Atomic library references to atomic types66 *67 * WG14 DR485: yes68 * Problem with the specification of ATOMIC_VAR_INIT69 *70 * WG14 DR486: yes71 * Inconsistent specification for arithmetic on atomic objects72 *73 * WG14 DR490: yes74 * Unwritten Assumptions About if-then75 */76 77/* WG14 DR412: yes78 * #elif79 *80 * Note: this is testing that #elif behaves the same as #else followed by #if.81 */82#if 183#elif this is not a valid expression84#else85 #if this is not a valid expression86 #endif87#endif88 89/* WG14 DR413: yes90 * Initialization91 */92void dr413(void) {93 typedef struct {94 int k;95 int l;96 int a[2];97 } T;98 99 typedef struct {100 int i;101 T t;102 } S;103 104 /* Ensure that explicit initialization (.t = { ... }) takes precedence over a105 * later implicit partial initialization (.t.l = 41). The value should be 42,106 * not 0.107 */108 _Static_assert((S){ /* c89only-warning {{compound literals are a C99-specific feature}}109 expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}110 */111 1,112 .t = { /* c89only-warning {{designated initializers are a C99 feature}} */113 .l = 43, /* c89only-warning {{designated initializers are a C99 feature}}114 expected-note {{previous initialization is here}}115 */116 .k = 42,117 .a[1] = 19, /* expected-note {{previous initialization is here}} */118 .a[0] = 18119 },120 .t.l = 41, /* expected-warning {{initializer overrides prior initialization of this subobject}} */121 .t.a[1] = 17 /* expected-warning {{initializer overrides prior initialization of this subobject}} */122 }.t.k == 42, "");123}124 125/* WG14 DR423: partial126 * Defect Report relative to n1570: underspecification for qualified rvalues127 */128 129/* FIXME: this should pass because the qualifier on the return type should be130 * dropped when forming the function type.131 */132const int dr423_const(void);133int dr423_nonconst(void);134_Static_assert(__builtin_types_compatible_p(__typeof__(dr423_const), __typeof__(dr423_nonconst)), "fail"); /* expected-error {{fail}} */135 136void dr423_func(void) {137 const int i = 12;138 __typeof__(i) v1 = 12; /* expected-note {{variable 'v1' declared const here}} */139 __typeof__((const int)12) v2 = 12;140 141 v1 = 100; /* expected-error {{cannot assign to variable 'v1' with const-qualified type 'typeof (i)' (aka 'const int')}} */142 v2 = 100; /* Not an error; the qualifier was stripped. */143}144 145/* WG14 DR432: yes146 * Possible defect report: Is 0.0 required to be a representable value?147 *148 * We're going to lean on the fpclassify builtin to tell us whether 0.0149 * represents the value 0, and we'll test that adding and subtracting 0.0 does150 * not change the value, and we'll hope that's enough to validate this DR.151 */152_Static_assert(__builtin_fpclassify(0, 1, 2, 3, 4, 0.0f) == 4, "");153_Static_assert((1.0 / 3.0) + 0.0 == (1.0 / 3.0) - 0.0, ""); /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}} */154 155/* WG14 DR444: partial156 * Issues with alignment in C11, part 1157 */158void dr444(void) {159 _Alignas(int) int i;160 _Alignas(int) struct S {161 _Alignas(int) int i;162 } s;163 164 /* FIXME: This should be accepted as per this DR. */165 int j = (_Alignas(int) int){12}; /* expected-error {{expected expression}} */166 167 _Alignas(int) struct T { /* expected-warning {{'_Alignas' attribute ignored}} */168 int i;169 };170 171 struct U {172 _Alignas(int) int bit : 1; /* expected-error {{'_Alignas' attribute cannot be applied to a bit-field}} */173 };174 175 _Alignas(int) typedef int foo; /* expected-error {{'_Alignas' attribute only applies to variables and fields}} */176 _Alignas(int) register int bar; /* expected-error {{'_Alignas' attribute cannot be applied to a variable with 'register' storage class}} */177 _Alignas(int) void func(void); /* expected-error {{'_Alignas' attribute only applies to variables and fields}} */178 179 /* FIXME: it is correct for us to accept this per 6.7.3p5, but it seems like180 * a situation we'd want to diagnose because the alignments are different and181 * the user probably doesn't know which one "wins".182 */183 _Alignas(int) _Alignas(double) int k;184}185 186/* WG14 DR447: yes187 * Boolean from complex188 *189 * Ensure that the imaginary part contributes to the conversion to bool, not190 * just the real part.191 */192_Static_assert((_Bool)0.0 + 3.0 * (__extension__ 1.0iF), ""); /* c89only-warning {{'_Bool' is a C99 extension}}193 expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}194 */195_Static_assert(!(_Bool)0.0 + 0.0 * (__extension__ 1.0iF), ""); /* c89only-warning {{'_Bool' is a C99 extension}}196 expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}197 */198 199/* WG14 DR463: yes200 * Left-shifting into the sign bit201 *202 * This DR was NAD and leaves shifting a bit into the high bit of a signed203 * integer type undefined behavior, unlike in C++. Note, the diagnostic is also204 * issued in C++ for shifting into that bit despite being well-defined because205 * the code is questionable and should be validated by the programmer.206 */207void dr463(void) {208 (void)(1 << (__CHAR_BIT__ * sizeof(int))); /* expected-warning {{shift count >= width of type}} */209 (void)(1 << ((__CHAR_BIT__ * sizeof(int)) - 1));210}211 212/* WG14 DR478: yes213 * Valid uses of the main function214 */215int main(void) {216 /* This DR clarifies that C explicitly allows you to call main() in a hosted217 * environment; it is not special as it is in C++, so recursive calls are218 * fine as well as nonrecursive direct calls.219 */220 main(); /* ok */221}222 223void dr478(void) {224 int (*fp)(void) = main; /* ok */225 main(); /* ok */226}227 228/* WG14 DR481: yes229 * Controlling expression of _Generic primary expression230 */231void dr481(void) {232 /* The controlling expression undergoes lvalue to rvalue conversion, and that233 * performs array decay and strips qualifiers.234 */235 (void)_Generic("bla", char *: "blu");236 (void)_Generic((int const){ 0 }, int: "blu"); /* c89only-warning {{compound literals are a C99-specific feature}} */237 (void)_Generic(+(int const){ 0 }, int: "blu"); /* c89only-warning {{compound literals are a C99-specific feature}} */238 239 (void)_Generic("bla", /* expected-error {{controlling expression type 'char *' not compatible with any generic association type}} */240 char[4]: "blu"); /* expected-warning {{due to lvalue conversion of the controlling expression, association of type 'char[4]' will never be selected because it is of array type}} */241 242 (void)_Generic((int const){ 0 }, /* expected-error {{controlling expression type 'int' not compatible with any generic association type}}243 c89only-warning {{compound literals are a C99-specific feature}}244 */245 int const: "blu"); /* expected-warning {{due to lvalue conversion of the controlling expression, association of type 'const int' will never be selected because it is qualified}} */246 247 (void)_Generic(+(int const){ 0 }, /* expected-error {{controlling expression type 'int' not compatible with any generic association type}}248 c89only-warning {{compound literals are a C99-specific feature}}249 */250 int const: "blu"); /* expected-warning {{due to lvalue conversion of the controlling expression, association of type 'const int' will never be selected because it is qualified}} */251}252 253/* WG14 DR489: partial254 * Integer Constant Expression255 *256 * The DR is about whether unevaluated operands have to follow the same257 * restrictions as the rest of the expression in an ICE, and according to the258 * committee, they do.259 */260void dr489(void) {261 struct S {262 int bit : 12 || 1.0f; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}} */263 };264 enum E {265 Val = 0 && 1.0f /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}} */266 };267 268 int i;269 270 /* FIXME: mentioning the 'aligned' attribute is confusing, but also, should271 * this be folded as an ICE as a GNU extension? GCC does not fold it.272 */273 _Alignas(0 ? i++ : 8) char c; /* expected-error {{'aligned' attribute requires integer constant}} */274 275 /* FIXME: this should get the constant folding diagnostic as this is not a276 * valid ICE because the floating-point constants are not the immediate277 * operand of a cast. It should then also get a diagnostic about trying to278 * declare a VLA with static storage duration and the C99 extension warning279 * for VLAs in C89.280 */281 static int vla[sizeof(1.0f + 1.0f)];282 283 int val[5] = { [1 ? 0 : i--] = 12 }; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}284 c89only-warning {{designated initializers are a C99 feature}}285 */286 287 /* FIXME: this should be the constant folding diagnostic as this is not a288 * valid ICE because of the / operator.289 */290 _Static_assert(sizeof(0 / 0), "");291 292 /* FIXME: this should also get the constant folding diagnostic as this is not293 * a valid ICE because of the = operator.294 */295 (void)_Generic(i = 12, int : 0); /* expected-warning {{expression with side effects has no effect in an unevaluated context}} */296 297 switch (i) {298 case (int)0.0f: break; /* okay, a valid ICE */299 300 /* FIXME: this should be accepted in C23 and up without a diagnostic, as C23301 * added compound literals to the allowed list of things in an ICE. The302 * diagnostic is correct for C17 and earlier though.303 */304 case (int){ 2 }: break; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}305 c89only-warning {{compound literals are a C99-specific feature}}306 */307 case 12 || main(): break; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}} */308 }309}310 311/* WG14 DR492: yes312 * Named Child struct-union with no Member313 */314struct dr492_t {315 union U11 { /* expected-warning {{declaration does not declare anything}} */316 int m11;317 float m12;318 };319 int m13;320} dr492;321 322/* WG14 DR496: yes323 * offsetof questions324 */325void dr496(void) {326 struct A { int n, a [2]; };327 struct B { struct A a; };328 struct C { struct A a[1]; };329 330 /* Array access & member access expressions are now valid. */331 _Static_assert(__builtin_offsetof(struct B, a.n) == 0, "");332 /* First int below is for 'n' and the second int is for 'a[0]'; this presumes333 * there is no padding involved.334 */335 _Static_assert(__builtin_offsetof(struct B, a.a[1]) == sizeof(int) + sizeof(int), "");336 337 /* However, we do not support using the -> operator to access a member, even338 * if that would be a valid expression. FIXME: GCC accepts this, perhaps we339 * should as well.340 */341 (void)__builtin_offsetof(struct C, a->n); /* expected-error {{expected ')'}} \342 expected-note {{to match this '('}}343 */344 345 /* The DR asked a question about whether defining a new type within offsetof346 * is allowed. C23 N2350 had made this explicitly undefined behavior, but this347 * was later overturned when C23 DE-137 was accepted, making it well-formed.348 *349 * Additionally, GCC and Clang both support it as an extension in pre-C23350 * mode.351 */352 (void)__builtin_offsetof(struct S { int a; }, a); /* pre-c23-warning{{defining a type within '__builtin_offsetof' is a C23 extension}} */353}354 355/* WG14 DR499: yes356 * Anonymous structure in union behavior357 */358void dr499(void) {359 union U {360 struct {361 char B1;362 char B2;363 char B3;364 char B4;365 };366 int word;367 } u;368 369 /* Validate that B1, B2, B3, and B4 do not have overlapping storage, only the370 * anonymous structure and 'word' overlap.371 */372 _Static_assert(__builtin_offsetof(union U, B1) == 0, "");373 _Static_assert(__builtin_offsetof(union U, B2) == 1, "");374 _Static_assert(__builtin_offsetof(union U, B3) == 2, "");375 _Static_assert(__builtin_offsetof(union U, B4) == 3, "");376 _Static_assert(__builtin_offsetof(union U, word) == 0, "");377}378