msg_132.c revision 1.50
1 /* $NetBSD: msg_132.c,v 1.50 2025/01/02 17:35:02 rillig Exp $ */ 2 # 3 "msg_132.c" 3 4 // Test for message: conversion from '%s' to '%s' may lose accuracy [132] 5 6 /* lint1-extra-flags: -X 351 */ 7 8 /* 9 * NetBSD's default lint flags only include a single -a, which only flags 10 * narrowing conversions from long. To get warnings for all narrowing 11 * conversions, -a needs to be given more than once. 12 * 13 * https://gnats.netbsd.org/14531 14 */ 15 16 /* lint1-extra-flags: -aa */ 17 18 typedef unsigned char u8_t; 19 typedef unsigned short u16_t; 20 typedef unsigned int u32_t; 21 typedef unsigned long long u64_t; 22 typedef signed char s8_t; 23 typedef signed short s16_t; 24 typedef signed int s32_t; 25 typedef signed long long s64_t; 26 27 _Bool cond; 28 char ch; 29 30 u8_t u8; 31 u16_t u16; 32 u32_t u32; 33 u64_t u64; 34 35 s8_t s8; 36 s16_t s16; 37 s32_t s32; 38 s64_t s64; 39 40 struct bit_fields { 41 unsigned u1:1; 42 unsigned u2:2; 43 unsigned u3:3; 44 unsigned u4:4; 45 unsigned u5:5; 46 unsigned u6:6; 47 unsigned u7:7; 48 unsigned u8:8; 49 unsigned u9:9; 50 unsigned u10:10; 51 unsigned u11:11; 52 unsigned u12:12; 53 unsigned u32:32; 54 } bits; 55 56 57 void 58 unsigned_to_unsigned(void) 59 { 60 /* expect+1: warning: conversion from 'unsigned short' to 'unsigned char' may lose accuracy [132] */ 61 u8 = u16; 62 /* expect+1: warning: conversion from 'unsigned int' to 'unsigned char' may lose accuracy [132] */ 63 u8 = u32; 64 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned char' may lose accuracy [132] */ 65 u8 = u64; 66 67 u16 = u8; 68 /* expect+1: warning: conversion from 'unsigned int' to 'unsigned short' may lose accuracy [132] */ 69 u16 = u32; 70 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned short' may lose accuracy [132] */ 71 u16 = u64; 72 73 u32 = u8; 74 u32 = u16; 75 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned int' may lose accuracy [132] */ 76 u32 = u64; 77 78 u64 = u8; 79 u64 = u16; 80 u64 = u32; 81 } 82 83 void 84 unsigned_to_signed(void) 85 { 86 /* expect+1: warning: conversion from 'unsigned short' to 'signed char' may lose accuracy [132] */ 87 s8 = u16; 88 /* expect+1: warning: conversion from 'unsigned int' to 'signed char' may lose accuracy [132] */ 89 s8 = u32; 90 /* expect+1: warning: conversion from 'unsigned long long' to 'signed char' may lose accuracy [132] */ 91 s8 = u64; 92 93 s16 = u8; 94 /* expect+1: warning: conversion from 'unsigned int' to 'short' may lose accuracy [132] */ 95 s16 = u32; 96 /* expect+1: warning: conversion from 'unsigned long long' to 'short' may lose accuracy [132] */ 97 s16 = u64; 98 99 s32 = u8; 100 s32 = u16; 101 /* expect+1: warning: conversion from 'unsigned long long' to 'int' may lose accuracy [132] */ 102 s32 = u64; 103 104 s64 = u8; 105 s64 = u16; 106 s64 = u32; 107 } 108 109 void 110 signed_to_unsigned(void) 111 { 112 /* expect+1: warning: conversion from 'short' to 'unsigned char' may lose accuracy [132] */ 113 u8 = s16; 114 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 115 u8 = s32; 116 /* expect+1: warning: conversion from 'long long' to 'unsigned char' may lose accuracy [132] */ 117 u8 = s64; 118 119 u16 = s8; 120 /* expect+1: warning: conversion from 'int' to 'unsigned short' may lose accuracy [132] */ 121 u16 = s32; 122 /* expect+1: warning: conversion from 'long long' to 'unsigned short' may lose accuracy [132] */ 123 u16 = s64; 124 125 u32 = s8; 126 u32 = s16; 127 /* expect+1: warning: conversion from 'long long' to 'unsigned int' may lose accuracy [132] */ 128 u32 = s64; 129 130 u64 = s8; 131 u64 = s16; 132 u64 = s32; 133 } 134 135 void 136 signed_to_signed(void) 137 { 138 /* expect+1: warning: conversion from 'short' to 'signed char' may lose accuracy [132] */ 139 s8 = s16; 140 /* expect+1: warning: conversion from 'int' to 'signed char' may lose accuracy [132] */ 141 s8 = s32; 142 /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */ 143 s8 = s64; 144 145 s16 = s8; 146 /* expect+1: warning: conversion from 'int' to 'short' may lose accuracy [132] */ 147 s16 = s32; 148 /* expect+1: warning: conversion from 'long long' to 'short' may lose accuracy [132] */ 149 s16 = s64; 150 151 s32 = s8; 152 s32 = s16; 153 /* expect+1: warning: conversion from 'long long' to 'int' may lose accuracy [132] */ 154 s32 = s64; 155 156 s64 = s8; 157 s64 = s16; 158 s64 = s32; 159 } 160 161 /* 162 * Before tree.c 1.268 from 2021-04-06, lint wrongly warned that conversion 163 * to _Bool might lose accuracy. C99 6.3.1.2 defines a special conversion 164 * rule from scalar to _Bool though by comparing the value to 0. 165 */ 166 _Bool 167 to_bool(long a, long b) 168 { 169 /* seen in fp_lib.h, function wideRightShiftWithSticky */ 170 return a | b; 171 } 172 173 /* ARGSUSED */ 174 const char * 175 cover_build_plus_minus(const char *arr, double idx) 176 { 177 if (idx > 0.0) 178 /* expect+2: error: operands of '+' have incompatible types 'pointer to const char' and 'double' [107] */ 179 /* expect+1: error: function 'cover_build_plus_minus' expects to return value [214] */ 180 return arr + idx; 181 return arr + (unsigned int)idx; 182 } 183 184 int 185 non_constant_expression(void) 186 { 187 /* 188 * Even though this variable definition looks like a constant, it 189 * does not fall within C's definition of an integer constant 190 * expression. Due to that, lint does not perform constant folding 191 * on the expression built from this variable and thus doesn't know 192 * that the conversion will always succeed. 193 */ 194 const int not_a_constant = 8; 195 /* expect+1: warning: conversion from 'unsigned long long' to 'int' may lose accuracy [132] */ 196 return not_a_constant * 8ULL; 197 } 198 199 /* 200 * PR 36668 notices that lint wrongly complains about the possible loss. 201 * 202 * The expression 'u8_t << 8' is guaranteed to fit into an 'u16_t', and its 203 * lower 8 bits are guaranteed to be clear. 'u16_t | u8_t' is guaranteed to 204 * fit into 'u16_t'. 205 * 206 * Since tree.c 1.444 from 2022-05-26, lint tracks simple bitwise and 207 * arithmetic constraints across a single expression. 208 */ 209 void 210 be16dec(void) 211 { 212 /* 213 * Before tree.c 1.444 from 2022-05-26, lint complained that the 214 * conversion from 'int' to 'unsigned short' may lose accuracy. 215 */ 216 u16 = (u16_t)u8 << 8 | u8; 217 } 218 219 /* 220 * Since tree.c 1.434 from 2022-04-19, lint infers the possible values of 221 * expressions of the form 'integer & constant', see can_represent. 222 */ 223 void 224 be32enc(void) 225 { 226 u8 = u32 >> 24 & 0xff; 227 u8 = u32 >> 16 & 0xff; 228 u8 = u32 >> 8 & 0xff; 229 u8 = u32 & 0xff; 230 } 231 232 void 233 test_ic_mult(void) 234 { 235 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 236 u8 = u8 * u8; 237 u16 = u8 * u8; 238 /* expect+1: warning: conversion from 'int' to 'unsigned short' may lose accuracy [132] */ 239 u16 = u16 * u8; 240 u32 = u16 * u16; 241 242 u32 = u16 * 65537ULL; 243 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned int' may lose accuracy [132] */ 244 u32 = u16 * 65538ULL; 245 246 u16 = 0 * u16; 247 u16 = 1 * u16; 248 /* expect+1: warning: conversion from 'int' to 'unsigned short' may lose accuracy [132] */ 249 u16 = 2 * u16; 250 251 // from __BITS, __SHIFTIN, __SHIFTOUT 252 u32 = (u16 & 1023ULL) / 1ULL * 1024ULL | (u16 & 1023ULL) / 1ULL * 1ULL; 253 254 // FIXME 255 /* expect+1: warning: conversion from 'int' to 'signed char' may lose accuracy [132] */ 256 s8 = 1 * s8; 257 // FIXME 258 /* expect+1: warning: conversion from 'int' to 'short' may lose accuracy [132] */ 259 s16 = 1 * s16; 260 s32 = 1 * s32; 261 s64 = 1 * s64; 262 } 263 264 void 265 test_ic_div(void) 266 { 267 u8 = u8 / u8; 268 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 269 u8 = u16 / u8; 270 u16 = u8 / u8; 271 u16 = u32 / 65536; 272 /* expect+1: warning: conversion from 'unsigned int' to 'unsigned short' may lose accuracy [132] */ 273 u16 = u32 / 65535; 274 275 // FIXME 276 /* expect+1: warning: conversion from 'int' to 'signed char' may lose accuracy [132] */ 277 s8 = s8 / 1; 278 // FIXME 279 /* expect+1: warning: conversion from 'int' to 'short' may lose accuracy [132] */ 280 s16 = s16 / 1; 281 s32 = s32 / 1; 282 s64 = s64 / 1; 283 } 284 285 void 286 test_ic_mod(void) 287 { 288 /* The result is between 0 and 254. */ 289 u8 = u64 % u8; 290 291 /* The result is between 0 and 255. */ 292 u8 = u64 % 256; 293 294 /* The result is between 0 and 256. */ 295 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned char' may lose accuracy [132] */ 296 u8 = u64 % 257; 297 298 /* The result is between 0 and 1000. */ 299 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned char' may lose accuracy [132] */ 300 u8 = u64 % 1000; 301 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned int:9' may lose accuracy [132] */ 302 bits.u9 = u64 % 1000; 303 bits.u10 = u64 % 1000; 304 u16 = u64 % 1000; 305 306 s8 = s16 % s8; 307 /* expect+1: warning: conversion from 'int' to 'signed char' may lose accuracy [132] */ 308 s8 = s16 % s16; 309 s8 = s64 % 1; 310 s8 = s64 % (s16 & 1); 311 /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */ 312 s8 = s64 % (s16 & 0); 313 s8 = (s64 & 0x7f) % s64; 314 /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */ 315 s8 = (s64 & 0xff) % s64; 316 } 317 318 void 319 test_ic_plus(void) 320 { 321 /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */ 322 s8 = -129 + s64 % 1; 323 s8 = -128 + s64 % 1; 324 s8 = 127 + s64 % 1; 325 /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */ 326 s8 = 128 + s64 % 1; 327 328 /* expect+2: warning: conversion of negative constant -129 to unsigned type 'unsigned long long' [222] */ 329 /* expect+1: warning: conversion from 'unsigned long long' to 'signed char' may lose accuracy [132] */ 330 s8 = -129 + u64 % 1; 331 /* expect+2: warning: conversion of negative constant -128 to unsigned type 'unsigned long long' [222] */ 332 /* expect+1: warning: conversion from 'unsigned long long' to 'signed char' may lose accuracy [132] */ 333 s8 = -128 + u64 % 1; 334 s8 = 127 + u64 % 1; 335 /* expect+1: warning: conversion from 'unsigned long long' to 'signed char' may lose accuracy [132] */ 336 s8 = 128 + u64 % 1; 337 338 u8 = 0 + u64 % 1; 339 u8 = 255 + u64 % 1; 340 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned char' may lose accuracy [132] */ 341 u8 = 256 + u64 % 1; 342 343 u8 = s8 + 0x80; 344 u16 = s16 + 0x8000; 345 u32 = s32 + 0x80000000; 346 u64 = s64 + 0x8000000000000000; 347 348 // XXX: No warnings since portable_rank_cmp is the same for both sides. 349 bits.u11 = bits.u10 + bits.u10 + 1; 350 bits.u11 = bits.u10 + bits.u10 + 2; 351 bits.u11 = bits.u10 + 1024; 352 bits.u11 = bits.u10 + 1025; 353 354 u8 = bits.u7 + bits.u7 + 1; 355 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 356 u8 = bits.u7 + bits.u7 + 2; 357 u8 = bits.u7 + 128; 358 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 359 u8 = bits.u7 + 129; 360 361 // The result of the second '+' wraps around, thus the warning, 362 // even though the final result fits in a u16. 363 /* expect+1: warning: conversion from 'unsigned int' to 'unsigned short' may lose accuracy [132] */ 364 u16 = u32 % 0x00010000 + 0x80000000 + 0x80000000; 365 366 /* expect+1: warning: conversion from 'unsigned int' to 'unsigned short' may lose accuracy [132] */ 367 u16 = u32 % 0x00010000 + 0xffff8000; 368 /* expect+1: warning: conversion from 'unsigned int' to 'short' may lose accuracy [132] */ 369 s16 = u32 % 0x00010000 + 0xffff8000; 370 371 /* expect+1: warning: conversion from 'long long' to 'unsigned short' may lose accuracy [132] */ 372 u16 = s64 % 0x00010000 + 0xffffffffLL + -0xffffffffLL; 373 /* expect+1: warning: conversion from 'int' to 'unsigned short' may lose accuracy [132] */ 374 u16 = s32 % 0x00010000 + 0x7fff0000 + -0x7fff0000; 375 /* expect+1: warning: conversion from 'unsigned int' to 'unsigned short' may lose accuracy [132] */ 376 u16 = u32 % 0x00010000 + 0xffff0000 + 0x00010000; 377 378 s8 = '0' + s64 % 10; 379 } 380 381 void 382 test_ic_minus(void) 383 { 384 // Shift the range [0x00 to 0xff] to [-0x80 to 0x7f]. 385 s8 = (s64 & 0xff) - 0x80; 386 387 // Sign-extend the lowest bits. 388 s8 = ((s64 & 0xff) ^ 0x80) - 0x80; 389 s16 = ((s64 & 0xffff) ^ 0x8000) - 0x8000; 390 /* expect+1: warning: extra bits set to 0 in conversion of 'unsigned int' to 'long long', op '&' [309] */ 391 s32 = ((s64 & 0xffffffff) ^ 0x80000000) - 0x80000000; 392 393 // Trying to sign-extend, but with off-by-one errors. 394 /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */ 395 s8 = ((s64 & 0xff) ^ 0x80) - 0x7f; 396 /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */ 397 s8 = ((s64 & 0xff) ^ 0x80) - 0x81; 398 399 u8 = s8 - -0x80; 400 u16 = s16 - -0x8000; 401 u32 = s32 - -0x80000000; 402 u64 = s64 - -0x8000000000000000; 403 } 404 405 void 406 test_ic_shl(void) 407 { 408 u64 = u64 << u64; 409 s64 = s64 << s64; 410 411 u16 = u8 << 8; 412 /* expect+1: warning: conversion from 'int' to 'unsigned short' may lose accuracy [132] */ 413 u16 = u8 << 9; 414 u32 = u16 << 16; 415 // XXX: missing warning as UINT has the same rank as INT, see portable_rank_cmp. 416 u32 = u16 << 17; 417 /* expect+1: warning: shift amount 56 is greater than bit-size 32 of 'int' [122] */ 418 u64 = u8 << 56; 419 u64 = (u64_t)u8 << 56; 420 // XXX: missing warning, as the operand types of '=' are the same, thus no conversion. 421 u64 = (u64_t)u8 << 57; 422 /* expect+1: warning: shift amount 48 is greater than bit-size 32 of 'int' [122] */ 423 u64 = u16 << 48; 424 u64 = (u64_t)u16 << 48; 425 // XXX: missing warning, as the operand types of '=' are the same, thus no conversion. 426 u64 = (u64_t)u16 << 49; 427 /* expect+1: warning: shift amount 32 equals bit-size of 'unsigned int' [267] */ 428 u64 = u32 << 32; 429 u64 = (u64_t)u32 << 32; 430 // XXX: missing warning, as the operand types of '=' are the same, thus no conversion. 431 u64 = (u64_t)u32 << 33; 432 } 433 434 void 435 test_ic_shr(void) 436 { 437 u64 = u64 >> u64; 438 s64 = s64 >> s64; 439 440 u32 = u64 >> 32; 441 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned int' may lose accuracy [132] */ 442 u32 = u64 >> 31; 443 u16 = u64 >> 48; 444 u16 = u32 >> 16; 445 u8 = u64 >> 56; 446 u8 = u32 >> 24; 447 u8 = u16 >> 8; 448 449 /* 450 * No matter whether the big integer is signed or unsigned, the 451 * result of '&' is guaranteed to be an unsigned value. 452 */ 453 u8 = (s64 & 0xf0) >> 4; 454 u8 = (s8 & 0xf0) >> 4; 455 } 456 457 void 458 test_ic_bitand(void) 459 { 460 u8 = u8 & u16; 461 462 /* expect+1: warning: conversion from 'unsigned int' to 'unsigned char' may lose accuracy [132] */ 463 u8 = u16 & u32; 464 } 465 466 void 467 test_ic_bitxor(void) 468 { 469 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 470 u8 = u8 ^ u16; 471 u16 = u8 ^ u16; 472 473 // Sign-extend. 474 s8 = (u8 ^ 0x80) - 0x80; 475 s16 = (u16 ^ 0x8000) - 0x8000; 476 s32 = (u32 ^ 0x80000000) - 0x80000000; 477 s64 = (u64 ^ 0x8000000000000000) - 0x8000000000000000; 478 } 479 480 void 481 test_ic_bitor(void) 482 { 483 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 484 u8 = u8 | u16; 485 u16 = u8 | u16; 486 /* expect+1: warning: conversion from 'unsigned int' to 'unsigned short' may lose accuracy [132] */ 487 u16 = u8 | u32; 488 u32 = u8 | u32; 489 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned int' may lose accuracy [132] */ 490 u32 = u8 | u64; 491 u64 = u8 | u64; 492 } 493 494 void 495 test_ic_quest_colon(char c1, char c2) 496 { 497 /* Both operands are representable as char. */ 498 ch = cond ? '?' : ':'; 499 500 /* 501 * Both operands are representable as char. Clang-Tidy 17 wrongly 502 * warns about a narrowing conversion from 'int' to signed type 503 * 'char'. 504 */ 505 ch = cond ? c1 : c2; 506 507 /* 508 * Mixing s8 and u8 results in a number from -128 to 255, which neither 509 * fits in s8 nor u8. 510 */ 511 /* expect+1: warning: conversion from 'int' to 'signed char' may lose accuracy [132] */ 512 s8 = cond ? s8 : u8; 513 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 514 u8 = cond ? s8 : u8; 515 } 516 517 void 518 test_ic_con(void) 519 { 520 /* expect+1: warning: assignment of negative constant -1 to unsigned type 'unsigned char' [164] */ 521 u8 = -1; 522 u8 = 0; 523 u8 = 255; 524 /* expect+1: warning: constant truncated by assignment [165] */ 525 u8 = 256; 526 527 /* expect+1: warning: conversion of 'int' to 'signed char' is out of range [119] */ 528 s8 = -129; 529 s8 = -128; 530 s8 = 127; 531 /* expect+1: warning: conversion of 'int' to 'signed char' is out of range [119] */ 532 s8 = 128; 533 } 534 535 void 536 test_ic_cvt(void) 537 { 538 u16 = (u32 & 0x0000ff00); 539 u16 = (u32_t)(u32 & 0x0000ff00); 540 u16 = (u16_t)u32; 541 u16 = (u8_t)(u32 & 0xffff) << 8; 542 u16 = (int)3.0; 543 544 u8 = (u8_t)(u64 & 0x0f); 545 u8 = (u8_t)(u64 & 0x0f) << 4; 546 /* expect+1: warning: conversion from 'int' to 'unsigned char' may lose accuracy [132] */ 547 u8 = (u8_t)(u64 & 0x0f) << 5; 548 } 549 550 unsigned char 551 test_bit_fields(unsigned long long m) 552 { 553 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned int:3' may lose accuracy [132] */ 554 bits.u3 = bits.u32 & m; 555 556 bits.u5 = bits.u3 & m; 557 bits.u32 = bits.u5 & m; 558 559 /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned char' may lose accuracy [132] */ 560 return bits.u32 & m; 561 } 562 563 void 564 compare_bit_field_to_integer_constant(void) 565 { 566 static _Bool b; 567 static struct { 568 short s16:15; 569 unsigned short u16:15; 570 int s32:15; 571 unsigned u32:15; 572 long long s64:15; 573 unsigned long long u64:15; 574 } s; 575 576 // Since decl.c 1.180 from 2021-05-02 and before tree.c 1.624 from 577 // 2024-03-12, lint warned about a possible loss of accuracy [132] 578 // when promoting an 'unsigned long long' bit-field to 'int'. 579 b = s.s16 == 0; 580 b = s.u16 == 0; 581 b = s.s32 == 0; 582 b = s.u32 == 0; 583 b = s.s64 == 0; 584 b = s.u64 == 0; 585 b = !b; 586 } 587 588 /* 589 * Before tree.c 1.626 from 2024-03-26, the usual arithmetic conversions for 590 * bit-field types with the same base type but different widths simply took 591 * the type of the left operand, leading to wrong warnings about loss of 592 * accuracy when the right operand was wider than the left operand. 593 */ 594 void 595 binary_operators_on_bit_fields(void) 596 { 597 struct { 598 u64_t u15:15; 599 u64_t u48:48; 600 u64_t u64; 601 } s = { 0, 0, 0 }; 602 603 u64 = s.u15 | s.u48; 604 u64 = s.u48 | s.u15; 605 u64 = s.u15 | s.u48 | s.u64; 606 u64 = s.u64 | s.u48 | s.u15; 607 cond = (s.u15 | s.u48 | s.u64) != 0; 608 cond = (s.u64 | s.u48 | s.u15) != 0; 609 610 // Before tree.c from 1.638 from 2024-05-01, lint wrongly warned: 611 // warning: conversion of 'int' to 'int:4' is out of range [119] 612 s32 = 8 - bits.u3; 613 } 614 615 unsigned char 616 combine_arithmetic_and_bit_operations(void) 617 { 618 return 0xc0 | (u32 & 0x07c0) / 64; 619 } 620
Indexes created Fri Oct 03 02:09:57 GMT 2025