gcc/c-family/c.opt

   1 ; Options for the C, ObjC, C++ and ObjC++ front ends.
   2 ; Copyright (C) 2003-2019 Free Software Foundation, Inc.
   3 ;
   4 ; This file is part of GCC.
   5 ;
   6 ; GCC is free software; you can redistribute it and/or modify it under
   7 ; the terms of the GNU General Public License as published by the Free
   8 ; Software Foundation; either version 3, or (at your option) any later
   9 ; version.
  10 ;
  11 ; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 ; WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 ; FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 ; for more details.
  15 ;
  16 ; You should have received a copy of the GNU General Public License
  17 ; along with GCC; see the file COPYING3.  If not see
  18 ; <http://www.gnu.org/licenses/>.
  19
  20 ; See the GCC internals manual for a description of this file's format.
  21
  22 ; Please try to keep this file in ASCII collating order.
  23
  24 Language
  25 C
  26
  27 Language
  28 ObjC
  29
  30 Language
  31 C++
  32
  33 Language
  34 ObjC++
  35
  36 -all-warnings
  37 C ObjC C++ ObjC++ Warning Alias(Wall)
  38
  39 -ansi
  40 C ObjC C++ ObjC++ Alias(ansi)
  41
  42 -assert
  43 C ObjC C++ ObjC++ Separate Alias(A) MissingArgError(assertion missing after %qs)
  44
  45 -assert=
  46 C ObjC C++ ObjC++ Joined Alias(A) MissingArgError(assertion missing after %qs)
  47
  48 -comments
  49 C ObjC C++ ObjC++ Alias(C)
  50
  51 -comments-in-macros
  52 C ObjC C++ ObjC++ Alias(CC)
  53
  54 -define-macro
  55 C ObjC C++ ObjC++ Separate Alias(D) MissingArgError(macro name missing after %qs)
  56
  57 -define-macro=
  58 C ObjC C++ ObjC++ Joined Alias(D) MissingArgError(macro name missing after %qs)
  59
  60 -dependencies
  61 C ObjC C++ ObjC++ Alias(M)
  62
  63 -dump
  64 C ObjC C++ ObjC++ Separate Alias(d)
  65
  66 -dump=
  67 C ObjC C++ ObjC++ Joined Alias(d)
  68
  69 -imacros
  70 C ObjC C++ ObjC++ Separate Alias(imacros) MissingArgError(missing filename after %qs)
  71
  72 -imacros=
  73 C ObjC C++ ObjC++ Joined Alias(imacros) MissingArgError(missing filename after %qs)
  74
  75 -include
  76 C ObjC C++ ObjC++ Separate Alias(include) MissingArgError(missing filename after %qs)
  77
  78 -include=
  79 C ObjC C++ ObjC++ Joined Alias(include) MissingArgError(missing filename after %qs)
  80
  81 -include-barrier
  82 C ObjC C++ ObjC++ Alias(I, -)
  83
  84 -include-directory
  85 C ObjC C++ ObjC++ Separate Alias(I) MissingArgError(missing path after %qs)
  86
  87 -include-directory=
  88 C ObjC C++ ObjC++ Joined Alias(I) MissingArgError(missing path after %qs)
  89
  90 -include-directory-after
  91 C ObjC C++ ObjC++ Separate Alias(idirafter) MissingArgError(missing path after %qs)
  92
  93 -include-directory-after=
  94 C ObjC C++ ObjC++ Joined Alias(idirafter) MissingArgError(missing path after %qs)
  95
  96 -include-prefix
  97 C ObjC C++ ObjC++ Separate Alias(iprefix)
  98
  99 -include-prefix=
 100 C ObjC C++ ObjC++ JoinedOrMissing Alias(iprefix)
 101
 102 -include-with-prefix
 103 C ObjC C++ ObjC++ Separate Alias(iwithprefix)
 104
 105 -include-with-prefix=
 106 C ObjC C++ ObjC++ JoinedOrMissing Alias(iwithprefix)
 107
 108 -include-with-prefix-after
 109 C ObjC C++ ObjC++ Separate Alias(iwithprefix)
 110
 111 -include-with-prefix-after=
 112 C ObjC C++ ObjC++ JoinedOrMissing Alias(iwithprefix)
 113
 114 -include-with-prefix-before
 115 C ObjC C++ ObjC++ Separate Alias(iwithprefixbefore)
 116
 117 -include-with-prefix-before=
 118 C ObjC C++ ObjC++ JoinedOrMissing Alias(iwithprefixbefore)
 119
 120 -no-integrated-cpp
 121 Driver Alias(no-integrated-cpp)
 122
 123 -no-line-commands
 124 C ObjC C++ ObjC++ Alias(P)
 125
 126 -no-standard-includes
 127 C ObjC C++ ObjC++ Alias(nostdinc)
 128
 129 -no-warnings
 130 C ObjC C++ ObjC++ Alias(w)
 131
 132 -output
 133 C ObjC C++ ObjC++ Separate Alias(o)
 134
 135 -output=
 136 C ObjC C++ ObjC++ Joined Alias(o)
 137
 138 -output-pch=
 139 C ObjC C++ ObjC++ Joined Separate
 140
 141 -pedantic
 142 C ObjC C++ ObjC++ Alias(pedantic)
 143
 144 -preprocess
 145 C ObjC C++ ObjC++ Undocumented Alias(E)
 146
 147 -print-missing-file-dependencies
 148 C ObjC C++ ObjC++ Alias(MG)
 149
 150 -trace-includes
 151 C ObjC C++ ObjC++ Alias(H)
 152
 153 -traditional
 154 Driver Alias(traditional)
 155
 156 -traditional-cpp
 157 C ObjC C++ ObjC++ Alias(traditional-cpp)
 158
 159 -trigraphs
 160 C ObjC C++ ObjC++ Alias(trigraphs)
 161
 162 -undefine-macro
 163 C ObjC C++ ObjC++ Separate Alias(U) MissingArgError(macro name missing after %qs)
 164
 165 -undefine-macro=
 166 C ObjC C++ ObjC++ Joined Alias(U) MissingArgError(macro name missing after %qs)
 167
 168 -user-dependencies
 169 C ObjC C++ ObjC++ Alias(MM)
 170
 171 -verbose
 172 Common C ObjC C++ ObjC++ Alias(v)
 173
 174 -write-dependencies
 175 C ObjC C++ ObjC++ NoDriverArg Separate Alias(MD) MissingArgError(missing filename after %qs)
 176
 177 -write-user-dependencies
 178 C ObjC C++ ObjC++ NoDriverArg Separate Alias(MMD) MissingArgError(missing filename after %qs)
 179
 180 A
 181 C ObjC C++ ObjC++ Joined Separate MissingArgError(assertion missing after %qs)
 182 -A<question>=<answer>   Assert the <answer> to <question>.  Putting '-' before <question> disables the <answer> to <question>.
 183
 184 C
 185 C ObjC C++ ObjC++
 186 Do not discard comments.
 187
 188 CC
 189 C ObjC C++ ObjC++
 190 Do not discard comments in macro expansions.
 191
 192 D
 193 C ObjC C++ ObjC++ Joined Separate MissingArgError(macro name missing after %qs)
 194 -D<macro>[=<val>]       Define a <macro> with <val> as its value.  If just <macro> is given, <val> is taken to be 1.
 195
 196 E
 197 C ObjC C++ ObjC++ Undocumented Var(flag_preprocess_only)
 198
 199 F
 200 Driver C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
 201 -F <dir>        Add <dir> to the end of the main framework include path.
 202
 203 fgimple
 204 C Var(flag_gimple) Init(0)
 205 Enable parsing GIMPLE.
 206
 207 H
 208 C ObjC C++ ObjC++
 209 Print the name of header files as they are used.
 210
 211 I
 212 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
 213 -I <dir>        Add <dir> to the end of the main include path.
 214
 215 M
 216 C ObjC C++ ObjC++
 217 Generate make dependencies.
 218
 219 MD
 220 C ObjC C++ ObjC++ NoDriverArg Separate MissingArgError(missing filename after %qs)
 221 Generate make dependencies and compile.
 222
 223 MF
 224 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing filename after %qs)
 225 -MF <file>      Write dependency output to the given file.
 226
 227 MG
 228 C ObjC C++ ObjC++
 229 Treat missing header files as generated files.
 230
 231 MM
 232 C ObjC C++ ObjC++
 233 Like -M but ignore system header files.
 234
 235 MMD
 236 C ObjC C++ ObjC++ NoDriverArg Separate MissingArgError(missing filename after %qs)
 237 Like -MD but ignore system header files.
 238
 239 MP
 240 C ObjC C++ ObjC++
 241 Generate phony targets for all headers.
 242
 243 MQ
 244 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing makefile target after %qs)
 245 -MQ <target>    Add a MAKE-quoted target.
 246
 247 MT
 248 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing makefile target after %qs)
 249 -MT <target>    Add an unquoted target.
 250
 251 P
 252 C ObjC C++ ObjC++
 253 Do not generate #line directives.
 254
 255 U
 256 C ObjC C++ ObjC++ Joined Separate MissingArgError(macro name missing after %qs)
 257 -U<macro>       Undefine <macro>.
 258
 259 Wabi
 260 C ObjC C++ ObjC++ LTO Var(warn_abi) Warning
 261 Warn about things that will change when compiling with an ABI-compliant compiler.
 262
 263 Wabi=
 264 C ObjC C++ ObjC++ LTO Joined RejectNegative UInteger Warning
 265 Warn about things that change between the current -fabi-version and the specified version.
 266
 267 Wabi-tag
 268 C++ ObjC++ Var(warn_abi_tag) Warning
 269 Warn if a subobject has an abi_tag attribute that the complete object type does not have.
 270
 271 Wpsabi
 272 C ObjC C++ ObjC++ LTO Var(warn_psabi) Init(1) Warning Undocumented LangEnabledBy(C ObjC C++ ObjC++,Wabi)
 273
 274 Wabsolute-value
 275 C ObjC Var(warn_absolute_value) Warning EnabledBy(Wextra)
 276 Warn on suspicious calls of standard functions computing absolute values.
 277
 278 Waddress
 279 C ObjC C++ ObjC++ Var(warn_address) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 280 Warn about suspicious uses of memory addresses.
 281
 282 Enum
 283 Name(warn_aligned_new_level) Type(int) UnknownError(argument %qs to %<-Waligned-new%> not recognized)
 284
 285 EnumValue
 286 Enum(warn_aligned_new_level) String(none) Value(0)
 287
 288 EnumValue
 289 Enum(warn_aligned_new_level) String(global) Value(1)
 290
 291 EnumValue
 292 Enum(warn_aligned_new_level) String(all) Value(2)
 293
 294 Waligned-new
 295 C++ ObjC++ Alias(Waligned-new=,global,none)
 296 Warn about 'new' of type with extended alignment without -faligned-new.
 297
 298 Waligned-new=
 299 C++ ObjC++ Var(warn_aligned_new) Enum(warn_aligned_new_level) Joined RejectNegative Warning LangEnabledBy(C++ ObjC++,Wall,1,0)
 300 -Waligned-new=[none|global|all] Warn even if 'new' uses a class member allocation function.
 301
 302 Wall
 303 C ObjC C++ ObjC++ Warning
 304 Enable most warning messages.
 305
 306 Walloca
 307 C ObjC C++ ObjC++ Var(warn_alloca) Warning
 308 Warn on any use of alloca.
 309
 310 Walloc-size-larger-than=
 311 C ObjC C++ LTO ObjC++ Var(warn_alloc_size_limit) Joined Host_Wide_Int ByteSize Warning Init(HOST_WIDE_INT_MAX)
 312 -Walloc-size-larger-than=<bytes> Warn for calls to allocation functions that
 313 attempt to allocate objects larger than the specified number of bytes.
 314
 315 Wno-alloc-size-larger-than
 316 C ObjC C++ LTO ObjC++ Alias(Walloc-size-larger-than=,18446744073709551615EiB,none) Warning
 317 -Wno-alloc-size-larger-than Disable Walloc-size-larger-than= warning.  Equivalent to Walloc-size-larger-than=<SIZE_MAX> or larger.
 318
 319 Walloc-zero
 320 C ObjC C++ ObjC++ Var(warn_alloc_zero) Warning
 321 -Walloc-zero Warn for calls to allocation functions that specify zero bytes.
 322
 323 Walloca-larger-than=
 324 C ObjC C++ LTO ObjC++ Var(warn_alloca_limit) Warning Joined Host_Wide_Int ByteSize Init(HOST_WIDE_INT_MAX)
 325 -Walloca-larger-than=<number>   Warn on unbounded uses of
 326 alloca, and on bounded uses of alloca whose bound can be larger than
 327 <number> bytes.
 328
 329 Wno-alloca-larger-than
 330 C ObjC C++ LTO ObjC++ Alias(Walloca-larger-than=,18446744073709551615EiB,none) Warning
 331 -Wno-alloca-larger-than Disable Walloca-larger-than= warning.  Equivalent to Walloca-larger-than=<SIZE_MAX> or larger.
 332
 333 Warray-bounds
 334 LangEnabledBy(C ObjC C++ LTO ObjC++)
 335 ; in common.opt
 336
 337 Warray-bounds=
 338 LangEnabledBy(C ObjC C++ LTO ObjC++,Wall,1,0)
 339 ; in common.opt
 340
 341 Wassign-intercept
 342 ObjC ObjC++ Var(warn_assign_intercept) Warning
 343 Warn whenever an Objective-C assignment is being intercepted by the garbage collector.
 344
 345 Wbad-function-cast
 346 C ObjC Var(warn_bad_function_cast) Warning
 347 Warn about casting functions to incompatible types.
 348
 349 Wbool-compare
 350 C ObjC C++ ObjC++ Var(warn_bool_compare) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 351 Warn about boolean expression compared with an integer value different from true/false.
 352
 353 Wbool-operation
 354 C ObjC C++ ObjC++ Var(warn_bool_op) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 355 Warn about certain operations on boolean expressions.
 356
 357 Wframe-address
 358 C ObjC C++ ObjC++ Var(warn_frame_address) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 359 Warn when __builtin_frame_address or __builtin_return_address is used unsafely.
 360
 361 Wbuiltin-declaration-mismatch
 362 C ObjC C++ ObjC++ Var(warn_builtin_declaraion_mismatch) Init(1) Warning
 363 Warn when a built-in function is declared with the wrong signature.
 364
 365 Wbuiltin-macro-redefined
 366 C ObjC C++ ObjC++ CPP(warn_builtin_macro_redefined) CppReason(CPP_W_BUILTIN_MACRO_REDEFINED) Var(cpp_warn_builtin_macro_redefined) Init(1) Warning
 367 Warn when a built-in preprocessor macro is undefined or redefined.
 368
 369 Wc11-c2x-compat
 370 C ObjC Var(warn_c11_c2x_compat) Init(-1) Warning
 371 Warn about features not present in ISO C11, but present in ISO C2X.
 372
 373 Wc90-c99-compat
 374 C ObjC CPP(cpp_warn_c90_c99_compat) CppReason(CPP_W_C90_C99_COMPAT) Var(warn_c90_c99_compat) Init(-1) Warning
 375 Warn about features not present in ISO C90, but present in ISO C99.
 376
 377 Wc99-c11-compat
 378 C ObjC Var(warn_c99_c11_compat) Init(-1) Warning
 379 Warn about features not present in ISO C99, but present in ISO C11.
 380
 381 Wc++-compat
 382 C ObjC Var(warn_cxx_compat) CPP(warn_cxx_operator_names) CppReason(CPP_W_CXX_OPERATOR_NAMES) Init(0) Warning
 383 Warn about C constructs that are not in the common subset of C and C++.
 384
 385 Wc++0x-compat
 386 C++ ObjC++ Warning Alias(Wc++11-compat) Undocumented
 387
 388 Wc++11-compat
 389 C++ ObjC++ Var(warn_cxx11_compat) Warning LangEnabledBy(C++ ObjC++,Wall) Init(0) CPP(cpp_warn_cxx11_compat) CppReason(CPP_W_CXX11_COMPAT)
 390 Warn about C++ constructs whose meaning differs between ISO C++ 1998 and ISO C++ 2011.
 391
 392 Wc++14-compat
 393 C++ ObjC++ Var(warn_cxx14_compat) Warning LangEnabledBy(C++ ObjC++,Wall)
 394 Warn about C++ constructs whose meaning differs between ISO C++ 2011 and ISO C++ 2014.
 395
 396 Wc++1z-compat
 397 C++ ObjC++ Warning Alias(Wc++17-compat) Undocumented
 398
 399 Wc++17-compat
 400 C++ ObjC++ Var(warn_cxx17_compat) Warning LangEnabledBy(C++ ObjC++,Wall)
 401 Warn about C++ constructs whose meaning differs between ISO C++ 2014 and ISO C++ 2017.
 402
 403 Wcast-function-type
 404 C ObjC C++ ObjC++ Var(warn_cast_function_type) Warning EnabledBy(Wextra)
 405 Warn about casts between incompatible function types.
 406
 407 Wcast-qual
 408 C ObjC C++ ObjC++ Var(warn_cast_qual) Warning
 409 Warn about casts which discard qualifiers.
 410
 411 Wcatch-value
 412 C++ ObjC++ Warning Alias(Wcatch-value=, 1, 0)
 413 Warn about catch handlers of non-reference type.
 414
 415 Wcatch-value=
 416 C++ ObjC++ Var(warn_catch_value) Warning Joined RejectNegative UInteger LangEnabledBy(C++ ObjC++,Wall, 1, 0) IntegerRange(0, 3)
 417 Warn about catch handlers of non-reference type.
 418
 419 Wchar-subscripts
 420 C ObjC C++ ObjC++ Var(warn_char_subscripts) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 421 Warn about subscripts whose type is \"char\".
 422
 423 Wchkp
 424 C ObjC C++ ObjC++ Warning Deprecated
 425 Deprecated in GCC 9.  This switch has no effect.
 426
 427 Wclobbered
 428 C ObjC C++ ObjC++ Var(warn_clobbered) Warning EnabledBy(Wextra)
 429 Warn about variables that might be changed by \"longjmp\" or \"vfork\".
 430
 431 Wcomment
 432 C ObjC C++ ObjC++ CPP(warn_comments) CppReason(CPP_W_COMMENTS) Var(cpp_warn_comment) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 433 Warn about possibly nested block comments, and C++ comments spanning more than one physical line.
 434
 435 Wcomments
 436 C ObjC C++ ObjC++ Warning Alias(Wcomment)
 437 Synonym for -Wcomment.
 438
 439 Wconditionally-supported
 440 C++ ObjC++ Var(warn_conditionally_supported) Warning
 441 Warn for conditionally-supported constructs.
 442
 443 Wconversion
 444 C ObjC C++ ObjC++ Var(warn_conversion) Warning
 445 Warn for implicit type conversions that may change a value.
 446
 447 Wconversion-null
 448 C++ ObjC++ Var(warn_conversion_null) Init(1) Warning
 449 Warn for converting NULL from/to a non-pointer type.
 450
 451 Wcpp
 452 C ObjC C++ ObjC++ CppReason(CPP_W_WARNING_DIRECTIVE)
 453 ; Documented in common.opt
 454
 455 Wctor-dtor-privacy
 456 C++ ObjC++ Var(warn_ctor_dtor_privacy) Warning
 457 Warn when all constructors and destructors are private.
 458
 459 Wdangling-else
 460 C ObjC C++ ObjC++ Var(warn_dangling_else) Warning LangEnabledBy(C ObjC C++ ObjC++,Wparentheses)
 461 Warn about dangling else.
 462
 463 Wdate-time
 464 C ObjC C++ ObjC++ CPP(warn_date_time) CppReason(CPP_W_DATE_TIME) Var(cpp_warn_date_time) Init(0) Warning
 465 Warn about __TIME__, __DATE__ and __TIMESTAMP__ usage.
 466
 467 Wdeclaration-after-statement
 468 C ObjC Var(warn_declaration_after_statement) Init(-1) Warning
 469 Warn when a declaration is found after a statement.
 470
 471 Wdelete-incomplete
 472 C++ ObjC++ Var(warn_delete_incomplete) Init(1) Warning
 473 Warn when deleting a pointer to incomplete type.
 474
 475 Wdelete-non-virtual-dtor
 476 C++ ObjC++ Var(warn_delnonvdtor) Warning LangEnabledBy(C++ ObjC++,Wall || Weffc++)
 477 Warn about deleting polymorphic objects with non-virtual destructors.
 478
 479 Wdeprecated
 480 C C++ ObjC ObjC++ CPP(cpp_warn_deprecated) CppReason(CPP_W_DEPRECATED) Var(warn_deprecated) Init(1) Warning
 481 Warn if a deprecated compiler feature, class, method, or field is used.
 482
 483 Wdeprecated-copy
 484 C++ ObjC++ Var(warn_deprecated_copy) Warning LangEnabledBy(C++ ObjC++, Wextra)
 485 Mark implicitly-declared copy operations as deprecated if the class has a
 486 user-provided copy operation.
 487
 488 Wdeprecated-copy-dtor
 489 C++ ObjC++ Var(warn_deprecated_copy, 2) Warning
 490 Mark implicitly-declared copy operations as deprecated if the class has a
 491 user-provided copy operation or destructor.
 492
 493 Wdesignated-init
 494 C ObjC Var(warn_designated_init) Init(1) Warning
 495 Warn about positional initialization of structs requiring designated initializers.
 496
 497 Wdiscarded-array-qualifiers
 498 C ObjC Var(warn_discarded_array_qualifiers) Init(1) Warning
 499 Warn if qualifiers on arrays which are pointer targets are discarded.
 500
 501 Wdiscarded-qualifiers
 502 C ObjC Var(warn_discarded_qualifiers) Init(1) Warning
 503 Warn if type qualifiers on pointers are discarded.
 504
 505 Wdiv-by-zero
 506 C ObjC C++ ObjC++ Var(warn_div_by_zero) Init(1) Warning
 507 Warn about compile-time integer division by zero.
 508
 509 Wduplicated-branches
 510 C ObjC C++ ObjC++ Var(warn_duplicated_branches) Init(0) Warning
 511 Warn about duplicated branches in if-else statements.
 512
 513 Wduplicated-cond
 514 C ObjC C++ ObjC++ Var(warn_duplicated_cond) Init(0) Warning
 515 Warn about duplicated conditions in an if-else-if chain.
 516
 517 Weffc++
 518 C++ ObjC++ Var(warn_ecpp) Warning
 519 Warn about violations of Effective C++ style rules.
 520
 521 Wempty-body
 522 C ObjC C++ ObjC++ Var(warn_empty_body) Warning EnabledBy(Wextra)
 523 Warn about an empty body in an if or else statement.
 524
 525 Wendif-labels
 526 C ObjC C++ ObjC++ CPP(warn_endif_labels) CppReason(CPP_W_ENDIF_LABELS) Var(cpp_warn_endif_labels) Init(1) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
 527 Warn about stray tokens after #else and #endif.
 528
 529 Wenum-compare
 530 C ObjC C++ ObjC++ Var(warn_enum_compare) Init(-1) Warning LangEnabledBy(C ObjC,Wall || Wc++-compat)
 531 Warn about comparison of different enum types.
 532
 533 Werror
 534 C ObjC C++ ObjC++
 535 ; Documented in common.opt
 536
 537 Werror-implicit-function-declaration
 538 C ObjC RejectNegative Warning Alias(Werror=, implicit-function-declaration)
 539 This switch is deprecated; use -Werror=implicit-function-declaration instead.
 540
 541 Wextra
 542 C ObjC C++ ObjC++ Warning
 543 ; in common.opt
 544
 545 Wextra-semi
 546 C++ ObjC++ Var(warn_extra_semi) Warning
 547 Warn about semicolon after in-class function definition.
 548
 549 Wfloat-conversion
 550 C ObjC C++ ObjC++ Var(warn_float_conversion) Warning LangEnabledBy(C ObjC C++ ObjC++,Wconversion)
 551 Warn for implicit type conversions that cause loss of floating point precision.
 552
 553 Wfloat-equal
 554 C ObjC C++ ObjC++ Var(warn_float_equal) Warning
 555 Warn if testing floating point numbers for equality.
 556
 557 Wformat
 558 C ObjC C++ ObjC++ Warning Alias(Wformat=, 1, 0)
 559 Warn about printf/scanf/strftime/strfmon format string anomalies.
 560
 561 Wformat-contains-nul
 562 C ObjC C++ ObjC++ Var(warn_format_contains_nul) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 1, 0)
 563 Warn about format strings that contain NUL bytes.
 564
 565 Wformat-extra-args
 566 C ObjC C++ ObjC++ Var(warn_format_extra_args) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 1, 0)
 567 Warn if passing too many arguments to a function for its format string.
 568
 569 Wformat-nonliteral
 570 C ObjC C++ ObjC++ Var(warn_format_nonliteral) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 2, 0)
 571 Warn about format strings that are not literals.
 572
 573 Wformat-overflow
 574 C ObjC C++ LTO ObjC++ Warning Alias(Wformat-overflow=, 1, 0) IntegerRange(0, 2)
 575 Warn about function calls with format strings that write past the end
 576 of the destination region.  Same as -Wformat-overflow=1.
 577
 578 Wformat-security
 579 C ObjC C++ ObjC++ Var(warn_format_security) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 2, 0)
 580 Warn about possible security problems with format functions.
 581
 582 Wformat-signedness
 583 C ObjC C++ ObjC++ Var(warn_format_signedness) Warning
 584 Warn about sign differences with format functions.
 585
 586 Wformat-truncation
 587 C ObjC C++ LTO ObjC++ Warning Alias(Wformat-truncation=, 1, 0)
 588 Warn about calls to snprintf and similar functions that truncate output.
 589 Same as -Wformat-truncation=1.
 590
 591 Wformat-y2k
 592 C ObjC C++ ObjC++ Var(warn_format_y2k) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=,warn_format >= 2, 0)
 593 Warn about strftime formats yielding 2-digit years.
 594
 595 Wformat-zero-length
 596 C ObjC C++ ObjC++ Var(warn_format_zero_length) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=,warn_format >= 1, 0)
 597 Warn about zero-length formats.
 598
 599 Wformat=
 600 C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_format) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall, 1, 0) IntegerRange(0, 2)
 601 Warn about printf/scanf/strftime/strfmon format string anomalies.
 602
 603 Wformat-overflow=
 604 C ObjC C++ LTO ObjC++ Joined RejectNegative UInteger Var(warn_format_overflow) Warning LangEnabledBy(C ObjC C++ LTO ObjC++,Wformat=, warn_format >= 1, 0) IntegerRange(0, 2)
 605 Warn about function calls with format strings that write past the end
 606 of the destination region.
 607
 608 Wformat-truncation=
 609 C ObjC C++ LTO ObjC++ Joined RejectNegative UInteger Var(warn_format_trunc) Warning LangEnabledBy(C ObjC C++ LTO ObjC++,Wformat=, warn_format >= 1, 0) IntegerRange(0, 2)
 610 Warn about calls to snprintf and similar functions that truncate output.
 611
 612 Wif-not-aligned
 613 C ObjC C++ ObjC++ Var(warn_if_not_aligned) Init(1) Warning
 614 Warn when the field in a struct is not aligned.
 615
 616 Wignored-qualifiers
 617 C C++ Var(warn_ignored_qualifiers) Warning EnabledBy(Wextra)
 618 Warn whenever type qualifiers are ignored.
 619
 620 Wignored-attributes
 621 C C++ Var(warn_ignored_attributes) Init(1) Warning
 622 Warn whenever attributes are ignored.
 623
 624 Wincompatible-pointer-types
 625 C ObjC Var(warn_incompatible_pointer_types) Init(1) Warning
 626 Warn when there is a conversion between pointers that have incompatible types.
 627
 628 Waddress-of-packed-member
 629 C ObjC C++ ObjC++ Var(warn_address_of_packed_member) Init(1) Warning
 630 Warn when the address of packed member of struct or union is taken.
 631
 632 Winit-self
 633 C ObjC C++ ObjC++ Var(warn_init_self) Warning LangEnabledBy(C++ ObjC++,Wall)
 634 Warn about variables which are initialized to themselves.
 635
 636 Winit-list-lifetime
 637 C++ ObjC++ Var(warn_init_list) Warning Init(1)
 638 Warn about uses of std::initializer_list that can result in dangling pointers.
 639
 640 Wimplicit
 641 C ObjC Var(warn_implicit) Warning LangEnabledBy(C ObjC,Wall)
 642 Warn about implicit declarations.
 643
 644 Wimplicit-fallthrough=
 645 LangEnabledBy(C ObjC C++ ObjC++,Wextra,3,0)
 646 ; in common.opt
 647
 648 Wdouble-promotion
 649 C ObjC C++ ObjC++ Var(warn_double_promotion) Warning
 650 Warn about implicit conversions from \"float\" to \"double\".
 651
 652 Wexpansion-to-defined
 653 C ObjC C++ ObjC++ CPP(warn_expansion_to_defined) CppReason(CPP_W_EXPANSION_TO_DEFINED) Var(cpp_warn_expansion_to_defined) Init(0) Warning EnabledBy(Wextra || Wpedantic)
 654 Warn if \"defined\" is used outside #if.
 655
 656 Wimplicit-function-declaration
 657 C ObjC Var(warn_implicit_function_declaration) Init(-1) Warning LangEnabledBy(C ObjC,Wimplicit)
 658 Warn about implicit function declarations.
 659
 660 Wimplicit-int
 661 C ObjC Var(warn_implicit_int) Init(-1) Warning LangEnabledBy(C ObjC,Wimplicit)
 662 Warn when a declaration does not specify a type.
 663
 664 Wimport
 665 C ObjC C++ ObjC++ Undocumented Ignore
 666
 667 Winherited-variadic-ctor
 668 C++ ObjC++ Var(warn_inh_var_ctor) Init(1) Warning
 669 Warn about C++11 inheriting constructors when the base has a variadic constructor.
 670
 671 Wint-conversion
 672 C ObjC Var(warn_int_conversion) Init(1) Warning
 673 Warn about incompatible integer to pointer and pointer to integer conversions.
 674
 675 Wint-in-bool-context
 676 C ObjC C++ ObjC++ Var(warn_int_in_bool_context) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 677 Warn for suspicious integer expressions in boolean context.
 678
 679 Wint-to-pointer-cast
 680 C ObjC C++ ObjC++ Var(warn_int_to_pointer_cast) Init(1) Warning
 681 Warn when there is a cast to a pointer from an integer of a different size.
 682
 683 Winvalid-offsetof
 684 C++ ObjC++ Var(warn_invalid_offsetof) Init(1) Warning
 685 Warn about invalid uses of the \"offsetof\" macro.
 686
 687 Winvalid-pch
 688 C ObjC C++ ObjC++ CPP(warn_invalid_pch) CppReason(CPP_W_INVALID_PCH) Var(cpp_warn_invalid_pch) Init(0) Warning
 689 Warn about PCH files that are found but not used.
 690
 691 Wjump-misses-init
 692 C ObjC Var(warn_jump_misses_init) Warning LangEnabledby(C ObjC,Wc++-compat)
 693 Warn when a jump misses a variable initialization.
 694
 695 Wliteral-suffix
 696 C++ ObjC++ CPP(warn_literal_suffix) CppReason(CPP_W_LITERAL_SUFFIX) Var(cpp_warn_literal_suffix) Init(1) Warning
 697 Warn when a string or character literal is followed by a ud-suffix which does not begin with an underscore.
 698
 699 Wlogical-op
 700 C ObjC C++ ObjC++ Var(warn_logical_op) Init(0) Warning
 701 Warn when a logical operator is suspiciously always evaluating to true or false.
 702
 703 Wlogical-not-parentheses
 704 C ObjC C++ ObjC++ Var(warn_logical_not_paren) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 705 Warn when logical not is used on the left hand side operand of a comparison.
 706
 707 Wlong-long
 708 C ObjC C++ ObjC++ CPP(cpp_warn_long_long) CppReason(CPP_W_LONG_LONG) Var(warn_long_long) Init(-1) Warning LangEnabledBy(C ObjC,Wc90-c99-compat)
 709 Do not warn about using \"long long\" when -pedantic.
 710
 711 Wmain
 712 C ObjC C++ ObjC++ Var(warn_main) Init(-1) Warning LangEnabledBy(C ObjC,Wall, 2, 0)
 713 Warn about suspicious declarations of \"main\".
 714
 715 Wmain
 716 LangEnabledBy(C ObjC C++ ObjC++,Wpedantic, 2, 0)
 717 ;
 718
 719 Wmemset-transposed-args
 720 C ObjC C++ ObjC++ Var(warn_memset_transposed_args) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 721 Warn about suspicious calls to memset where the third argument is constant literal zero and the second is not.
 722
 723 Wmemset-elt-size
 724 C ObjC C++ ObjC++ Var(warn_memset_elt_size) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 725 Warn about suspicious calls to memset where the third argument contains the number of elements not multiplied by the element size.
 726
 727 Wmisleading-indentation
 728 C C++ Common Var(warn_misleading_indentation) Warning LangEnabledBy(C C++,Wall)
 729 Warn when the indentation of the code does not reflect the block structure.
 730
 731 Wmissing-braces
 732 C ObjC C++ ObjC++ Var(warn_missing_braces) Warning LangEnabledBy(C ObjC,Wall)
 733 Warn about possibly missing braces around initializers.
 734
 735 Wmissing-declarations
 736 C ObjC C++ ObjC++ Var(warn_missing_declarations) Warning
 737 Warn about global functions without previous declarations.
 738
 739 Wmissing-field-initializers
 740 C ObjC C++ ObjC++ Var(warn_missing_field_initializers) Warning EnabledBy(Wextra)
 741 Warn about missing fields in struct initializers.
 742
 743 Wmultistatement-macros
 744 C ObjC C++ ObjC++ Var(warn_multistatement_macros) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 745 Warn about unsafe macros expanding to multiple statements used as a body of a clause such as if, else, while, switch, or for.
 746
 747 Wmultiple-inheritance
 748 C++ ObjC++ Var(warn_multiple_inheritance) Warning
 749 Warn on direct multiple inheritance.
 750
 751 Wnamespaces
 752 C++ ObjC++ Var(warn_namespaces) Warning
 753 Warn on namespace definition.
 754
 755 Wpacked-not-aligned
 756 C ObjC C++ ObjC++ Var(warn_packed_not_aligned) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 757 Warn when fields in a struct with the packed attribute are misaligned.
 758
 759 Wsized-deallocation
 760 C++ ObjC++ Var(warn_sized_deallocation) Warning EnabledBy(Wextra)
 761 Warn about missing sized deallocation functions.
 762
 763 Wsizeof-pointer-div
 764 C ObjC C++ ObjC++ Var(warn_sizeof_pointer_div) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 765 Warn about suspicious divisions of two sizeof expressions that don't work correctly with pointers.
 766
 767 Wsizeof-pointer-memaccess
 768 C ObjC C++ ObjC++ Var(warn_sizeof_pointer_memaccess) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 769 Warn about suspicious length parameters to certain string functions if the argument uses sizeof.
 770
 771 Wsizeof-array-argument
 772 C ObjC C++ ObjC++ Var(warn_sizeof_array_argument) Warning Init(1)
 773 Warn when sizeof is applied on a parameter declared as an array.
 774
 775 Wstringop-overflow
 776 C ObjC C++ LTO ObjC++ Warning Alias(Wstringop-overflow=, 2, 0)
 777 Warn about buffer overflow in string manipulation functions like memcpy
 778 and strcpy.
 779
 780 Wstringop-overflow=
 781 C ObjC C++ LTO ObjC++ Joined RejectNegative UInteger Var(warn_stringop_overflow) Init(2) Warning LangEnabledBy(C ObjC C++ LTO ObjC++, Wall, 2, 0) IntegerRange(0, 4)
 782 Under the control of Object Size type, warn about buffer overflow in string
 783 manipulation functions like memcpy and strcpy.
 784
 785 Wstringop-truncation
 786 C ObjC C++ LTO ObjC++ Var(warn_stringop_truncation) Warning Init (1) LangEnabledBy(C ObjC C++ LTO ObjC++, Wall)
 787 Warn about truncation in string manipulation functions like strncat and strncpy.
 788
 789 Wsuggest-attribute=format
 790 C ObjC C++ ObjC++ Var(warn_suggest_attribute_format) Warning
 791 Warn about functions which might be candidates for format attributes.
 792
 793 Wsuggest-override
 794 C++ ObjC++ Var(warn_override) Warning
 795 Suggest that the override keyword be used when the declaration of a virtual
 796 function overrides another.
 797
 798 Wswitch
 799 C ObjC C++ ObjC++ Var(warn_switch) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 800 Warn about enumerated switches, with no default, missing a case.
 801
 802 Wswitch-default
 803 C ObjC C++ ObjC++ Var(warn_switch_default) Warning
 804 Warn about enumerated switches missing a \"default:\" statement.
 805
 806 Wswitch-enum
 807 C ObjC C++ ObjC++ Var(warn_switch_enum) Warning
 808 Warn about all enumerated switches missing a specific case.
 809
 810 Wswitch-bool
 811 C ObjC C++ ObjC++ Var(warn_switch_bool) Warning Init(1)
 812 Warn about switches with boolean controlling expression.
 813
 814 Wtemplates
 815 C++ ObjC++ Var(warn_templates) Warning
 816 Warn on primary template declaration.
 817
 818 Wmissing-attributes
 819 C ObjC C++ ObjC++ Var(warn_missing_attributes) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 820 Warn about declarations of entities that may be missing attributes
 821 that related entities have been declared with it.
 822
 823 Wmissing-format-attribute
 824 C ObjC C++ ObjC++ Warning Alias(Wsuggest-attribute=format)
 825 ;
 826
 827 Wmissing-include-dirs
 828 C ObjC C++ ObjC++ CPP(warn_missing_include_dirs) CppReason(CPP_W_MISSING_INCLUDE_DIRS) Var(cpp_warn_missing_include_dirs) Init(0) Warning
 829 Warn about user-specified include directories that do not exist.
 830
 831 Wmissing-parameter-type
 832 C ObjC Var(warn_missing_parameter_type) Warning EnabledBy(Wextra)
 833 Warn about function parameters declared without a type specifier in K&R-style functions.
 834
 835 Wmissing-prototypes
 836 C ObjC Var(warn_missing_prototypes) Warning
 837 Warn about global functions without prototypes.
 838
 839 Wmudflap
 840 C ObjC C++ ObjC++ Deprecated
 841
 842 Wmultichar
 843 C ObjC C++ ObjC++ CPP(warn_multichar) CppReason(CPP_W_MULTICHAR) Var(cpp_warn_multichar) Init(0) Warning
 844 Warn about use of multi-character character constants.
 845
 846 Wnarrowing
 847 C ObjC C++ ObjC++ Warning Var(warn_narrowing) Init(-1) LangEnabledBy(C++ ObjC++,Wall || Wc++11-compat)
 848 Warn about narrowing conversions within { } that are ill-formed in C++11.
 849
 850 Wnested-externs
 851 C ObjC Var(warn_nested_externs) Warning
 852 Warn about \"extern\" declarations not at file scope.
 853
 854 Wnoexcept
 855 C++ ObjC++ Var(warn_noexcept) Warning
 856 Warn when a noexcept expression evaluates to false even though the expression can't actually throw.
 857
 858 Wnoexcept-type
 859 C++ ObjC++ Warning Var(warn_noexcept_type) LangEnabledBy(C++ ObjC++,Wabi || Wc++17-compat)
 860 Warn if C++17 noexcept function type will change the mangled name of a symbol.
 861
 862 Wnon-template-friend
 863 C++ ObjC++ Var(warn_nontemplate_friend) Init(1) Warning
 864 Warn when non-templatized friend functions are declared within a template.
 865
 866 Wclass-conversion
 867 C++ ObjC++ Var(warn_class_conversion) Init(1) Warning
 868 Warn when a conversion function will never be called due to the type it converts to.
 869
 870 Wclass-memaccess
 871 C++ ObjC++ Var(warn_class_memaccess) Warning LangEnabledBy(C++ ObjC++, Wall)
 872 Warn for unsafe raw memory writes to objects of class types.
 873
 874 Wnon-virtual-dtor
 875 C++ ObjC++ Var(warn_nonvdtor) Warning LangEnabledBy(C++ ObjC++,Weffc++)
 876 Warn about non-virtual destructors.
 877
 878 Wnonnull
 879 C ObjC C++ LTO ObjC++ Var(warn_nonnull) Warning LangEnabledBy(C ObjC C++ LTO ObjC++,Wformat=,warn_format >= 1,0)
 880 Warn about NULL being passed to argument slots marked as requiring non-NULL.
 881
 882 Wnonnull
 883 C ObjC C++ LTO ObjC++ LangEnabledBy(C ObjC C++ LTO ObjC++,Wall)
 884 ;
 885
 886 Wnonnull-compare
 887 C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
 888 ;
 889
 890 Wnormalized
 891 C ObjC C++ ObjC++ Warning Alias(Wnormalized=,nfc,none)
 892 ;
 893
 894 Wnormalized=
 895 C ObjC C++ ObjC++ RejectNegative Joined Warning CPP(warn_normalize) CppReason(CPP_W_NORMALIZE) Init(normalized_C) Var(cpp_warn_normalize) Enum(cpp_normalize_level)
 896 -Wnormalized=[none|id|nfc|nfkc] Warn about non-normalized Unicode strings.
 897
 898 ; Required for these enum values.
 899 SourceInclude
 900 cpplib.h
 901
 902 Enum
 903 Name(cpp_normalize_level) Type(int) UnknownError(argument %qs to %<-Wnormalized%> not recognized)
 904
 905 EnumValue
 906 Enum(cpp_normalize_level) String(none) Value(normalized_none)
 907
 908 EnumValue
 909 Enum(cpp_normalize_level) String(nfkc) Value(normalized_KC)
 910
 911 EnumValue
 912 Enum(cpp_normalize_level) String(id) Value(normalized_identifier_C)
 913
 914 EnumValue
 915 Enum(cpp_normalize_level) String(nfc) Value(normalized_C)
 916
 917 Wold-style-cast
 918 C++ ObjC++ Var(warn_old_style_cast) Warning
 919 Warn if a C-style cast is used in a program.
 920
 921 Wold-style-declaration
 922 C ObjC Var(warn_old_style_declaration) Warning EnabledBy(Wextra)
 923 Warn for obsolescent usage in a declaration.
 924
 925 Wold-style-definition
 926 C ObjC Var(warn_old_style_definition) Warning
 927 Warn if an old-style parameter definition is used.
 928
 929 Wopenmp-simd
 930 C C++ Var(warn_openmp_simd) Warning LangEnabledBy(C C++,Wall)
 931 Warn if a simd directive is overridden by the vectorizer cost model.
 932
 933 Woverlength-strings
 934 C ObjC C++ ObjC++ Var(warn_overlength_strings) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
 935 Warn if a string is longer than the maximum portable length specified by the standard.
 936
 937 Woverloaded-virtual
 938 C++ ObjC++ Var(warn_overloaded_virtual) Warning
 939 Warn about overloaded virtual function names.
 940
 941 Woverride-init
 942 C ObjC Var(warn_override_init) Warning EnabledBy(Wextra)
 943 Warn about overriding initializers without side effects.
 944
 945 Woverride-init-side-effects
 946 C ObjC Var(warn_override_init_side_effects) Init(1) Warning
 947 Warn about overriding initializers with side effects.
 948
 949 Wpacked-bitfield-compat
 950 C ObjC C++ ObjC++ Var(warn_packed_bitfield_compat) Init(-1) Warning
 951 Warn about packed bit-fields whose offset changed in GCC 4.4.
 952
 953 Wparentheses
 954 C ObjC C++ ObjC++ Var(warn_parentheses) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 955 Warn about possibly missing parentheses.
 956
 957 Wpedantic
 958 C ObjC C++ ObjC++ CPP(cpp_pedantic) CppReason(CPP_W_PEDANTIC) Warning
 959 ; Documented in common.opt
 960
 961 Wpessimizing-move
 962 C++ ObjC++ Var(warn_pessimizing_move) Warning LangEnabledBy(C++ ObjC++, Wall)
 963 Warn about calling std::move on a local object in a return statement preventing copy elision.
 964
 965 Wpmf-conversions
 966 C++ ObjC++ Var(warn_pmf2ptr) Init(1) Warning
 967 Warn when converting the type of pointers to member functions.
 968
 969 Wpointer-arith
 970 C ObjC C++ ObjC++ Var(warn_pointer_arith) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
 971 Warn about function pointer arithmetic.
 972
 973 Wpointer-sign
 974 C ObjC Var(warn_pointer_sign) Warning LangEnabledBy(C ObjC,Wall || Wpedantic)
 975 Warn when a pointer differs in signedness in an assignment.
 976
 977 Wpointer-compare
 978 C ObjC C++ ObjC++ Var(warn_pointer_compare) Init(1) Warning
 979 Warn when a pointer is compared with a zero character constant.
 980
 981 Wpointer-to-int-cast
 982 C ObjC Var(warn_pointer_to_int_cast) Init(1) Warning
 983 Warn when a pointer is cast to an integer of a different size.
 984
 985 Wpragmas
 986 C ObjC C++ ObjC++ Var(warn_pragmas) Init(1) Warning
 987 Warn about misuses of pragmas.
 988
 989 Wprio-ctor-dtor
 990 C ObjC C++ ObjC++ Var(warn_prio_ctor_dtor) Init(1) Warning
 991 Warn if constructor or destructors with priorities from 0 to 100 are used.
 992
 993 Wproperty-assign-default
 994 ObjC ObjC++ Var(warn_property_assign_default) Init(1) Warning
 995 Warn if a property for an Objective-C object has no assign semantics specified.
 996
 997 Wprotocol
 998 ObjC ObjC++ Var(warn_protocol) Init(1) Warning
 999 Warn if inherited methods are unimplemented.
1000
1001 Wplacement-new
1002 C++ Warning Alias(Wplacement-new=, 1, 0)
1003 Warn for placement new expressions with undefined behavior.
1004
1005 Wplacement-new=
1006 C++ Joined RejectNegative UInteger Var(warn_placement_new) Init(-1) Warning IntegerRange(0, 2)
1007 Warn for placement new expressions with undefined behavior.
1008
1009 Wredundant-decls
1010 C ObjC C++ ObjC++ Var(warn_redundant_decls) Warning
1011 Warn about multiple declarations of the same object.
1012
1013 Wredundant-move
1014 C++ ObjC++ Var(warn_redundant_move) Warning LangEnabledBy(C++ ObjC++,Wextra)
1015 Warn about redundant calls to std::move.
1016
1017 Wregister
1018 C++ ObjC++ Var(warn_register) Warning
1019 Warn about uses of register storage specifier.
1020
1021 Wreorder
1022 C++ ObjC++ Var(warn_reorder) Warning LangEnabledBy(C++ ObjC++,Wall)
1023 Warn when the compiler reorders code.
1024
1025 Wreturn-type
1026 C ObjC C++ ObjC++ Var(warn_return_type) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall) Init(-1)
1027 Warn whenever a function's return type defaults to \"int\" (C), or about inconsistent return types (C++).
1028
1029 Wscalar-storage-order
1030 C ObjC C++ ObjC++ Init(1) Warning
1031 Warn on suspicious constructs involving reverse scalar storage order.
1032
1033 Wselector
1034 ObjC ObjC++ Var(warn_selector) Warning
1035 Warn if a selector has multiple methods.
1036
1037 Wsequence-point
1038 C ObjC C++ ObjC++ Var(warn_sequence_point) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
1039 Warn about possible violations of sequence point rules.
1040
1041 Wshadow-ivar
1042 ObjC ObjC++ Var(warn_shadow_ivar) EnabledBy(Wshadow) Init(1) Warning
1043 Warn if a local declaration hides an instance variable.
1044
1045 Wshift-overflow
1046 C ObjC C++ ObjC++ Warning Alias(Wshift-overflow=, 1, 0)
1047 Warn if left shift of a signed value overflows.
1048
1049 Wshift-overflow=
1050 C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_shift_overflow) Init(-1) Warning IntegerRange(0, 2)
1051 Warn if left shift of a signed value overflows.
1052
1053 Wshift-count-negative
1054 C ObjC C++ ObjC++ Var(warn_shift_count_negative) Init(1) Warning
1055 Warn if shift count is negative.
1056
1057 Wshift-count-overflow
1058 C ObjC C++ ObjC++ Var(warn_shift_count_overflow) Init(1) Warning
1059 Warn if shift count >= width of type.
1060
1061 Wshift-negative-value
1062 C ObjC C++ ObjC++ Var(warn_shift_negative_value) Init(-1) Warning
1063 Warn if left shifting a negative value.
1064
1065 Wsign-compare
1066 C ObjC C++ ObjC++ Var(warn_sign_compare) Warning LangEnabledBy(C++ ObjC++,Wall)
1067 Warn about signed-unsigned comparisons.
1068
1069 Wsign-compare
1070 C ObjC C++ ObjC++ EnabledBy(Wextra)
1071 ;
1072
1073 Wsign-conversion
1074 C ObjC C++ ObjC++ Var(warn_sign_conversion) Warning LangEnabledBy(C ObjC,Wconversion)
1075 Warn for implicit type conversions between signed and unsigned integers.
1076
1077 Wsign-promo
1078 C++ ObjC++ Var(warn_sign_promo) Warning
1079 Warn when overload promotes from unsigned to signed.
1080
1081 Wstrict-null-sentinel
1082 C++ ObjC++ Warning Var(warn_strict_null_sentinel)
1083 Warn about uncasted NULL used as sentinel.
1084
1085 Wstrict-prototypes
1086 C ObjC Var(warn_strict_prototypes) Warning
1087 Warn about unprototyped function declarations.
1088
1089 Wstrict-aliasing=
1090 C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall, 3, 0) IntegerRange(0, 3)
1091 ;
1092
1093 Wstrict-overflow=
1094 C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall, 1, 0) IntegerRange(0, 5)
1095 ;
1096
1097 Wstrict-selector-match
1098 ObjC ObjC++ Var(warn_strict_selector_match) Warning
1099 Warn if type signatures of candidate methods do not match exactly.
1100
1101 Wsync-nand
1102 C C++ Var(warn_sync_nand) Init(1) Warning
1103 Warn when __sync_fetch_and_nand and __sync_nand_and_fetch built-in functions are used.
1104
1105 Wsynth
1106 C++ ObjC++ Var(warn_synth) Warning
1107 Deprecated.  This switch has no effect.
1108
1109 Wsystem-headers
1110 C ObjC C++ ObjC++ Warning
1111 ; Documented in common.opt
1112
1113 Wtautological-compare
1114 C ObjC C++ ObjC++ Var(warn_tautological_compare) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
1115 Warn if a comparison always evaluates to true or false.
1116
1117 Wterminate
1118 C++ ObjC++ Warning Var(warn_terminate) Init(1)
1119 Warn if a throw expression will always result in a call to terminate().
1120
1121 Wtraditional
1122 C ObjC CPP(cpp_warn_traditional) CppReason(CPP_W_TRADITIONAL) Var(warn_traditional) Init(0) Warning
1123 Warn about features not present in traditional C.
1124
1125 Wtraditional-conversion
1126 C ObjC Var(warn_traditional_conversion) Warning
1127 Warn of prototypes causing type conversions different from what would happen in the absence of prototype.
1128
1129 Wtrigraphs
1130 C ObjC C++ ObjC++ CPP(warn_trigraphs) CppReason(CPP_W_TRIGRAPHS) Var(cpp_warn_trigraphs) Init(2) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
1131 Warn if trigraphs are encountered that might affect the meaning of the program.
1132
1133 Wundeclared-selector
1134 ObjC ObjC++ Var(warn_undeclared_selector) Warning
1135 Warn about @selector()s without previously declared methods.
1136
1137 Wundef
1138 C ObjC C++ ObjC++ CPP(warn_undef) CppReason(CPP_W_UNDEF) Var(cpp_warn_undef) Init(0) Warning
1139 Warn if an undefined macro is used in an #if directive.
1140
1141 Wuninitialized
1142 C ObjC C++ ObjC++ LTO LangEnabledBy(C ObjC C++ ObjC++ LTO,Wall)
1143 ;
1144
1145 Wmaybe-uninitialized
1146 C ObjC C++ ObjC++ LTO LangEnabledBy(C ObjC C++ ObjC++ LTO,Wall)
1147 ;
1148
1149 Wunknown-pragmas
1150 C ObjC C++ ObjC++ Warning Var(warn_unknown_pragmas) LangEnabledBy(C ObjC C++ ObjC++,Wall, 1, 0)
1151 Warn about unrecognized pragmas.
1152
1153 Wunsuffixed-float-constants
1154 C ObjC Var(warn_unsuffixed_float_constants) Warning
1155 Warn about unsuffixed float constants.
1156
1157 Wunused
1158 C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
1159 ; documented in common.opt
1160
1161 Wunused-local-typedefs
1162 C ObjC C++ ObjC++ Var(warn_unused_local_typedefs) Warning EnabledBy(Wunused)
1163 Warn when typedefs locally defined in a function are not used.
1164
1165 Wunused-macros
1166 C ObjC C++ ObjC++ CppReason(CPP_W_UNUSED_MACROS) Var(cpp_warn_unused_macros) Warning
1167 Warn about macros defined in the main file that are not used.
1168
1169 Wunused-result
1170 C ObjC C++ ObjC++ Var(warn_unused_result) Init(1) Warning
1171 Warn if a caller of a function, marked with attribute warn_unused_result, does not use its return value.
1172
1173 Wunused-variable
1174 C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wunused)
1175 ; documented in common.opt
1176
1177 Wunused-const-variable
1178 C ObjC C++ ObjC++ Warning Alias(Wunused-const-variable=, 2, 0)
1179 Warn when a const variable is unused.
1180
1181 Wunused-const-variable=
1182 C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_unused_const_variable) Warning LangEnabledBy(C ObjC,Wunused-variable, 1, 0) IntegerRange(0, 2)
1183 Warn when a const variable is unused.
1184
1185 Wvariadic-macros
1186 C ObjC C++ ObjC++ CPP(warn_variadic_macros) CppReason(CPP_W_VARIADIC_MACROS) Var(cpp_warn_variadic_macros) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic || Wtraditional)
1187 Warn about using variadic macros.
1188
1189 Wvarargs
1190 C ObjC C++ ObjC++ Warning Var(warn_varargs) Init(1)
1191 Warn about questionable usage of the macros used to retrieve variable arguments.
1192
1193 Wvla
1194 C ObjC C++ ObjC++ Var(warn_vla) Init(-1) Warning
1195 Warn if a variable length array is used.
1196
1197 Wvla-larger-than=
1198 C ObjC C++ LTO ObjC++ Var(warn_vla_limit) Warning Joined Host_Wide_Int ByteSize Init(HOST_WIDE_INT_MAX)
1199 -Wvla-larger-than=<number>      Warn on unbounded uses of variable-length
1200 arrays, and on bounded uses of variable-length arrays whose bound can be
1201 larger than <number> bytes.
1202 <number> bytes.
1203
1204 Wno-vla-larger-than
1205 C ObjC C++ LTO ObjC++ Alias(Wvla-larger-than=,18446744073709551615EiB,none) Warning
1206 -Wno-vla-larger-than Disable Wvla-larger-than= warning.  Equivalent to Wvla-larger-than=<SIZE_MAX> or larger.
1207
1208 Wvolatile-register-var
1209 C ObjC C++ ObjC++ Var(warn_volatile_register_var) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
1210 Warn when a register variable is declared volatile.
1211
1212 Wvirtual-inheritance
1213 C++ ObjC++ Var(warn_virtual_inheritance) Warning
1214 Warn on direct virtual inheritance.
1215
1216 Wvirtual-move-assign
1217 C++ ObjC++ Var(warn_virtual_move_assign) Warning Init(1)
1218 Warn if a virtual base has a non-trivial move assignment operator.
1219
1220 Wwrite-strings
1221 C ObjC C++ ObjC++ Var(warn_write_strings) Warning
1222 In C++, nonzero means warn about deprecated conversion from string literals to 'char *'.  In C, similar warning, except that the conversion is of course not deprecated by the ISO C standard.
1223
1224 Wzero-as-null-pointer-constant
1225 C++ ObjC++ Var(warn_zero_as_null_pointer_constant) Warning
1226 Warn when a literal '0' is used as null pointer.
1227
1228 Wuseless-cast
1229 C++ ObjC++ Var(warn_useless_cast) Warning
1230 Warn about useless casts.
1231
1232 Wsubobject-linkage
1233 C++ ObjC++ Var(warn_subobject_linkage) Warning Init(1)
1234 Warn if a class type has a base or a field whose type uses the anonymous namespace or depends on a type with no linkage.
1235
1236 Wduplicate-decl-specifier
1237 C ObjC Var(warn_duplicate_decl_specifier) Warning LangEnabledBy(C ObjC,Wall)
1238 Warn when a declaration has duplicate const, volatile, restrict or _Atomic specifier.
1239
1240 Wrestrict
1241 C ObjC C++ ObjC++ Var(warn_restrict) Warning LangEnabledBy(C ObjC C++ ObjC++, Wall)
1242 Warn when an argument passed to a restrict-qualified parameter aliases with
1243 another argument.
1244
1245 ansi
1246 C ObjC C++ ObjC++
1247 A synonym for -std=c89 (for C) or -std=c++98 (for C++).
1248
1249 d
1250 C ObjC C++ ObjC++ Joined
1251 ; Documented in common.opt.  FIXME - what about -dI, -dD, -dN and -dD?
1252
1253 fabi-compat-version=
1254 C++ ObjC++ Joined RejectNegative UInteger Var(flag_abi_compat_version) Init(-1)
1255 The version of the C++ ABI used for -Wabi warnings and link compatibility aliases.
1256
1257 faccess-control
1258 C++ ObjC++ Var(flag_access_control) Init(1)
1259 Enforce class member access control semantics.
1260
1261 fada-spec-parent=
1262 C ObjC C++ ObjC++ RejectNegative Joined Var(ada_specs_parent)
1263 -fada-spec-parent=unit  Dump Ada specs as child units of given parent.
1264
1265 faligned-new
1266 C++ ObjC++ Alias(faligned-new=,1,0)
1267 Support C++17 allocation of over-aligned types.
1268
1269 faligned-new=
1270 C++ ObjC++ Joined RejectNegative Var(aligned_new_threshold) UInteger Init(-1)
1271 -faligned-new=<N> Use C++17 over-aligned type allocation for alignments greater than N.
1272
1273 fall-virtual
1274 C++ ObjC++ Deprecated
1275
1276 fallow-parameterless-variadic-functions
1277 C ObjC Var(flag_allow_parameterless_variadic_functions)
1278 Allow variadic functions without named parameter.
1279
1280 falt-external-templates
1281 C++ ObjC++ Deprecated
1282 No longer supported.
1283
1284 fasm
1285 C ObjC C++ ObjC++ Var(flag_no_asm, 0)
1286 Recognize the \"asm\" keyword.
1287
1288 ; Define extra predefined macros for use in libgcc.
1289 fbuilding-libgcc
1290 C ObjC C++ ObjC++ Undocumented Var(flag_building_libgcc)
1291
1292 fbuiltin
1293 C ObjC C++ ObjC++ Var(flag_no_builtin, 0)
1294 Recognize built-in functions.
1295
1296 fbuiltin-
1297 C ObjC C++ ObjC++ Joined
1298
1299 fcanonical-system-headers
1300 C ObjC C++ ObjC++
1301 Where shorter, use canonicalized paths to systems headers.
1302
1303 fcheck-pointer-bounds
1304 C ObjC C++ ObjC++ LTO Deprecated
1305 Deprecated in GCC 9.  This switch has no effect.
1306
1307 fchkp-check-incomplete-type
1308 C ObjC C++ ObjC++ LTO Deprecated
1309 Deprecated in GCC 9.  This switch has no effect.
1310
1311 fchkp-zero-input-bounds-for-main
1312 C ObjC C++ ObjC++ LTO Deprecated
1313 Deprecated in GCC 9.  This switch has no effect.
1314
1315 fchkp-first-field-has-own-bounds
1316 C ObjC C++ ObjC++ LTO Deprecated RejectNegative
1317 Deprecated in GCC 9.  This switch has no effect.
1318
1319 fchkp-narrow-bounds
1320 C ObjC C++ ObjC++ LTO Deprecated
1321 Deprecated in GCC 9.  This switch has no effect.
1322
1323 fchkp-narrow-to-innermost-array
1324 C ObjC C++ ObjC++ LTO Deprecated RejectNegative
1325 Deprecated in GCC 9.  This switch has no effect.
1326
1327 fchkp-flexible-struct-trailing-arrays
1328 C ObjC C++ ObjC++ LTO Deprecated
1329 Deprecated in GCC 9.  This switch has no effect.
1330
1331 fchkp-optimize
1332 C ObjC C++ ObjC++ LTO Deprecated
1333
1334 fchkp-use-fast-string-functions
1335 C ObjC C++ ObjC++ LTO Deprecated
1336 Deprecated in GCC 9.  This switch has no effect.
1337
1338 fchkp-use-nochk-string-functions
1339 C ObjC C++ ObjC++ LTO Deprecated
1340 Deprecated in GCC 9.  This switch has no effect.
1341
1342 fchkp-use-static-bounds
1343 C ObjC C++ ObjC++ LTO Deprecated
1344 Deprecated in GCC 9.  This switch has no effect.
1345
1346 fchkp-use-static-const-bounds
1347 C ObjC C++ ObjC++ LTO Deprecated
1348 Deprecated in GCC 9.  This switch has no effect.
1349
1350 fchkp-treat-zero-dynamic-size-as-infinite
1351 C ObjC C++ ObjC++ LTO Deprecated
1352 Deprecated in GCC 9.  This switch has no effect.
1353
1354 fchkp-check-read
1355 C ObjC C++ ObjC++ LTO Deprecated
1356 Deprecated in GCC 9.  This switch has no effect.
1357
1358 fchkp-check-write
1359 C ObjC C++ ObjC++ LTO Deprecated
1360 Deprecated in GCC 9.  This switch has no effect.
1361
1362 fchkp-store-bounds
1363 C ObjC C++ ObjC++ LTO Deprecated
1364 Deprecated in GCC 9.  This switch has no effect.
1365
1366 fchkp-instrument-calls
1367 C ObjC C++ ObjC++ LTO Deprecated
1368 Deprecated in GCC 9.  This switch has no effect.
1369
1370 fchkp-instrument-marked-only
1371 C ObjC C++ ObjC++ LTO Deprecated
1372 Deprecated in GCC 9.  This switch has no effect.
1373
1374 fchkp-use-wrappers
1375 C ObjC C++ ObjC++ LTO Deprecated
1376 Deprecated in GCC 9.  This switch has no effect.
1377
1378 static-libmpx
1379 Driver Deprecated
1380 Deprecated in GCC 9.  This switch has no effect.
1381
1382 static-libmpxwrappers
1383 Driver Deprecated
1384 Deprecated in GCC 9.  This switch has no effect.
1385
1386 fcilkplus
1387 C ObjC C++ ObjC++ LTO Undocumented Ignore
1388 Deprecated in GCC 8.  This switch has no effect.
1389
1390 fconcepts
1391 C++ ObjC++ Var(flag_concepts)
1392 Enable support for C++ concepts.
1393
1394 fcond-mismatch
1395 C ObjC C++ ObjC++
1396 Allow the arguments of the '?' operator to have different types.
1397
1398 fconserve-space
1399 C++ ObjC++ Ignore
1400 Does nothing.  Preserved for backward compatibility.
1401
1402 fconstant-string-class=
1403 ObjC ObjC++ Joined MissingArgError(no class name specified with %qs)
1404 -fconst-string-class=<name>     Use class <name> for constant strings.
1405
1406 fconstexpr-depth=
1407 C++ ObjC++ Joined RejectNegative UInteger Var(max_constexpr_depth) Init(512)
1408 -fconstexpr-depth=<number>      Specify maximum constexpr recursion depth.
1409
1410 fconstexpr-loop-limit=
1411 C++ ObjC++ Joined RejectNegative UInteger Var(constexpr_loop_limit) Init(262144)
1412 -fconstexpr-loop-limit=<number> Specify maximum constexpr loop iteration count.
1413
1414 fdebug-cpp
1415 C ObjC C++ ObjC++
1416 Emit debug annotations during preprocessing.
1417
1418 fdeduce-init-list
1419 C++ ObjC++ Var(flag_deduce_init_list) Init(0)
1420 -fdeduce-init-list      enable deduction of std::initializer_list for a template type parameter from a brace-enclosed initializer-list.
1421
1422 fdeclone-ctor-dtor
1423 C++ ObjC++ Var(flag_declone_ctor_dtor) Init(-1)
1424 Factor complex constructors and destructors to favor space over speed.
1425
1426 fdefault-inline
1427 C++ ObjC++ Ignore
1428 Does nothing.  Preserved for backward compatibility.
1429
1430 fdiagnostics-show-template-tree
1431 C++ ObjC++ Var(flag_diagnostics_show_template_tree) Init(0)
1432 Print hierarchical comparisons when template types are mismatched.
1433
1434 fdirectives-only
1435 C ObjC C++ ObjC++
1436 Preprocess directives only.
1437
1438 fdollars-in-identifiers
1439 C ObjC C++ ObjC++
1440 Permit '$' as an identifier character.
1441
1442 fmacro-prefix-map=
1443 C ObjC C++ ObjC++ Joined RejectNegative
1444 -fmacro-prefix-map=<old>=<new> Map one directory name to another in __FILE__, __BASE_FILE__, and __builtin_FILE().
1445
1446 fdump-ada-spec
1447 C ObjC C++ ObjC++ RejectNegative Var(flag_dump_ada_spec)
1448 Write all declarations as Ada code transitively.
1449
1450 fdump-ada-spec-slim
1451 C ObjC C++ ObjC++ RejectNegative Var(flag_dump_ada_spec_slim)
1452 Write all declarations as Ada code for the given file only.
1453
1454 felide-constructors
1455 C++ ObjC++ Var(flag_elide_constructors) Init(1)
1456
1457 felide-type
1458 C++ ObjC++ Var(flag_elide_type) Init(1)
1459 -fno-elide-type Do not elide common elements in template comparisons.
1460
1461 fenforce-eh-specs
1462 C++ ObjC++ Var(flag_enforce_eh_specs) Init(1)
1463 Generate code to check exception specifications.
1464
1465 fenum-int-equiv
1466 C++ ObjC++ Deprecated
1467
1468 fexec-charset=
1469 C ObjC C++ ObjC++ Joined RejectNegative
1470 -fexec-charset=<cset>   Convert all strings and character constants to character set <cset>.
1471
1472 fextended-identifiers
1473 C ObjC C++ ObjC++
1474 Permit universal character names (\\u and \\U) in identifiers.
1475
1476 finput-charset=
1477 C ObjC C++ ObjC++ Joined RejectNegative
1478 -finput-charset=<cset>  Specify the default character set for source files.
1479
1480 fextern-tls-init
1481 C++ ObjC++ Var(flag_extern_tls_init) Init(-1)
1482 Support dynamic initialization of thread-local variables in a different translation unit.
1483
1484 fexternal-templates
1485 C++ ObjC++ Deprecated
1486
1487 ffor-scope
1488 C++ ObjC++ Deprecated
1489
1490 ffreestanding
1491 C ObjC C++ ObjC++
1492 Do not assume that standard C libraries and \"main\" exist.
1493
1494 fgnu-keywords
1495 C++ ObjC++ Var(flag_no_gnu_keywords, 0)
1496 Recognize GNU-defined keywords.
1497
1498 fgnu-runtime
1499 ObjC ObjC++ LTO Report RejectNegative Var(flag_next_runtime,0) Init(NEXT_OBJC_RUNTIME)
1500 Generate code for GNU runtime environment.
1501
1502 fgnu89-inline
1503 C ObjC Var(flag_gnu89_inline) Init(-1)
1504 Use traditional GNU semantics for inline functions.
1505
1506 fguiding-decls
1507 C++ ObjC++ Deprecated
1508
1509 fhandle-exceptions
1510 C++ ObjC++ Optimization Alias(fexceptions) Warn({-fhandle-exceptions has been renamed -fexceptions (and is now on by default)})
1511
1512 fhonor-std
1513 C++ ObjC++ Deprecated
1514
1515 fhosted
1516 C ObjC
1517 Assume normal C execution environment.
1518
1519 fhuge-objects
1520 C++ ObjC++ Deprecated
1521 No longer supported.
1522
1523 fimplement-inlines
1524 C++ ObjC++ Var(flag_implement_inlines) Init(1)
1525 Export functions even if they can be inlined.
1526
1527 fimplicit-inline-templates
1528 C++ ObjC++ Var(flag_implicit_inline_templates) Init(1)
1529 Emit implicit instantiations of inline templates.
1530
1531 fimplicit-templates
1532 C++ ObjC++ Var(flag_implicit_templates) Init(1)
1533 Emit implicit instantiations of templates.
1534
1535 fnew-inheriting-ctors
1536 C++ ObjC++ Var(flag_new_inheriting_ctors) Init(1)
1537 Implement C++17 inheriting constructor semantics.
1538
1539 ffriend-injection
1540 C++ ObjC++ Deprecated
1541
1542 fkeep-inline-dllexport
1543 C C++ ObjC ObjC++ Var(flag_keep_inline_dllexport) Init(1) Report Condition(TARGET_DLLIMPORT_DECL_ATTRIBUTES)
1544 Don't emit dllexported inline functions unless needed.
1545
1546 flabels-ok
1547 C++ ObjC++ Deprecated
1548
1549 flax-vector-conversions
1550 C ObjC C++ ObjC++ Var(flag_lax_vector_conversions)
1551 Allow implicit conversions between vectors with differing numbers of subparts and/or differing element types.
1552
1553 fms-extensions
1554 C ObjC C++ ObjC++ Var(flag_ms_extensions)
1555 Don't warn about uses of Microsoft extensions.
1556
1557 fmudflap
1558 C ObjC C++ ObjC++ Deprecated
1559
1560 fmudflapth
1561 C ObjC C++ ObjC++ Deprecated
1562
1563 fmudflapir
1564 C ObjC C++ ObjC++ Deprecated
1565
1566 fname-mangling-version-
1567 C++ ObjC++ Joined Deprecated
1568
1569 fnew-abi
1570 C++ ObjC++ Deprecated
1571
1572 fnew-ttp-matching
1573 C++ ObjC++ Var(flag_new_ttp)
1574 Implement resolution of DR 150 for matching of template template arguments.
1575
1576 fnext-runtime
1577 ObjC ObjC++ LTO Report RejectNegative Var(flag_next_runtime)
1578 Generate code for NeXT (Apple Mac OS X) runtime environment.
1579
1580 fnil-receivers
1581 ObjC ObjC++ Var(flag_nil_receivers) Init(1)
1582 Assume that receivers of Objective-C messages may be nil.
1583
1584 flocal-ivars
1585 ObjC ObjC++ Var(flag_local_ivars) Init(1)
1586 Allow access to instance variables as if they were local declarations within instance method implementations.
1587
1588 fivar-visibility=
1589 ObjC ObjC++ Joined RejectNegative Enum(ivar_visibility) Var(default_ivar_visibility) Init(IVAR_VISIBILITY_PROTECTED)
1590 -fvisibility=[private|protected|public|package] Set the default symbol visibility.
1591
1592 Enum
1593 Name(ivar_visibility) Type(enum ivar_visibility) UnknownError(unrecognized ivar visibility value %qs)
1594
1595 EnumValue
1596 Enum(ivar_visibility) String(private) Value(IVAR_VISIBILITY_PRIVATE)
1597
1598 EnumValue
1599 Enum(ivar_visibility) String(protected) Value(IVAR_VISIBILITY_PROTECTED)
1600
1601 EnumValue
1602 Enum(ivar_visibility) String(public) Value(IVAR_VISIBILITY_PUBLIC)
1603
1604 EnumValue
1605 Enum(ivar_visibility) String(package) Value(IVAR_VISIBILITY_PACKAGE)
1606
1607 fnonansi-builtins
1608 C++ ObjC++ Var(flag_no_nonansi_builtin, 0)
1609
1610 fnonnull-objects
1611 C++ ObjC++ Deprecated
1612
1613 fnothrow-opt
1614 C++ ObjC++ Optimization Var(flag_nothrow_opt)
1615 Treat a throw() exception specification as noexcept to improve code size.
1616
1617 fobjc-abi-version=
1618 ObjC ObjC++ LTO Joined Report RejectNegative UInteger Var(flag_objc_abi)
1619 Specify which ABI to use for Objective-C family code and meta-data generation.
1620
1621 ; Generate special '- .cxx_construct' and '- .cxx_destruct' methods
1622 ; to initialize any non-POD ivars in Objective-C++ classes.
1623 fobjc-call-cxx-cdtors
1624 ObjC++ Var(flag_objc_call_cxx_cdtors)
1625 Generate special Objective-C methods to initialize/destroy non-POD C++ ivars, if needed.
1626
1627 fobjc-direct-dispatch
1628 ObjC ObjC++ Var(flag_objc_direct_dispatch)
1629 Allow fast jumps to the message dispatcher.
1630
1631 ; Nonzero means that we will allow new ObjC exception syntax (@throw,
1632 ; @try, etc.) in source code.
1633 fobjc-exceptions
1634 ObjC ObjC++ Var(flag_objc_exceptions)
1635 Enable Objective-C exception and synchronization syntax.
1636
1637 fobjc-gc
1638 ObjC ObjC++ LTO Var(flag_objc_gc)
1639 Enable garbage collection (GC) in Objective-C/Objective-C++ programs.
1640
1641 fobjc-nilcheck
1642 ObjC ObjC++ Var(flag_objc_nilcheck,1)
1643 Enable inline checks for nil receivers with the NeXT runtime and ABI version 2.
1644
1645 ; Nonzero means that we generate NeXT setjmp based exceptions.
1646 fobjc-sjlj-exceptions
1647 ObjC ObjC++ Var(flag_objc_sjlj_exceptions) Init(-1)
1648 Enable Objective-C setjmp exception handling runtime.
1649
1650 fobjc-std=objc1
1651 ObjC ObjC++ Var(flag_objc1_only)
1652 Conform to the Objective-C 1.0 language as implemented in GCC 4.0.
1653
1654 fopenacc
1655 C ObjC C++ ObjC++ LTO Var(flag_openacc)
1656 Enable OpenACC.
1657
1658 fopenacc-dim=
1659 C ObjC C++ ObjC++ LTO Joined Var(flag_openacc_dims)
1660 Specify default OpenACC compute dimensions.
1661
1662 fopenmp
1663 C ObjC C++ ObjC++ LTO Var(flag_openmp)
1664 Enable OpenMP (implies -frecursive in Fortran).
1665
1666 fopenmp-simd
1667 C ObjC C++ ObjC++ Var(flag_openmp_simd)
1668 Enable OpenMP's SIMD directives.
1669
1670 foperator-names
1671 C++ ObjC++
1672 Recognize C++ keywords like \"compl\" and \"xor\".
1673
1674 foptional-diags
1675 C++ ObjC++ Ignore
1676 Does nothing.  Preserved for backward compatibility.
1677
1678 fpch-deps
1679 C ObjC C++ ObjC++
1680
1681 fpch-preprocess
1682 C ObjC C++ ObjC++
1683 Look for and use PCH files even when preprocessing.
1684
1685 fpermissive
1686 C++ ObjC++ Var(flag_permissive)
1687 Downgrade conformance errors to warnings.
1688
1689 fplan9-extensions
1690 C ObjC Var(flag_plan9_extensions)
1691 Enable Plan 9 language extensions.
1692
1693 fpreprocessed
1694 C ObjC C++ ObjC++
1695 Treat the input file as already preprocessed.
1696
1697 ftrack-macro-expansion
1698 C ObjC C++ ObjC++ JoinedOrMissing RejectNegative UInteger
1699 ; converted into ftrack-macro-expansion=
1700
1701 ftrack-macro-expansion=
1702 C ObjC C++ ObjC++ JoinedOrMissing RejectNegative UInteger
1703 -ftrack-macro-expansion=<0|1|2>  Track locations of tokens coming from macro expansion and display them in error messages.
1704
1705 fpretty-templates
1706 C++ ObjC++ Var(flag_pretty_templates) Init(1)
1707 -fno-pretty-templates Do not pretty-print template specializations as the template signature followed by the arguments.
1708
1709 fprintf-return-value
1710 C ObjC C++ ObjC++ LTO Optimization Var(flag_printf_return_value) Init(1)
1711 Treat known sprintf return values as constants.
1712
1713 freplace-objc-classes
1714 ObjC ObjC++ LTO Var(flag_replace_objc_classes)
1715 Used in Fix-and-Continue mode to indicate that object files may be swapped in at runtime.
1716
1717 frepo
1718 C++ ObjC++
1719 Enable automatic template instantiation.
1720
1721 frtti
1722 C++ ObjC++ Optimization Var(flag_rtti) Init(1)
1723 Generate run time type descriptor information.
1724
1725 fshort-enums
1726 C ObjC C++ ObjC++ LTO Optimization Var(flag_short_enums)
1727 Use the narrowest integer type possible for enumeration types.
1728
1729 fshort-wchar
1730 C ObjC C++ ObjC++ LTO Optimization Var(flag_short_wchar)
1731 Force the underlying type for \"wchar_t\" to be \"unsigned short\".
1732
1733 fsigned-bitfields
1734 C ObjC C++ ObjC++ Var(flag_signed_bitfields) Init(1)
1735 When \"signed\" or \"unsigned\" is not given make the bitfield signed.
1736
1737 fsigned-char
1738 C ObjC C++ ObjC++ LTO Var(flag_signed_char)
1739 Make \"char\" signed by default.
1740
1741 fsized-deallocation
1742 C++ ObjC++ Var(flag_sized_deallocation) Init(-1)
1743 Enable C++14 sized deallocation support.
1744
1745 fsquangle
1746 C++ ObjC++ Deprecated
1747
1748 fsso-struct=
1749 C ObjC Joined RejectNegative Enum(sso_struct) Var(default_sso) Init(SSO_NATIVE)
1750 -fsso-struct=[big-endian|little-endian|native]  Set the default scalar storage order.
1751
1752 Enum
1753 Name(sso_struct) Type(enum scalar_storage_order_kind) UnknownError(unrecognized scalar storage order value %qs)
1754
1755 EnumValue
1756 Enum(sso_struct) String(big-endian) Value(SSO_BIG_ENDIAN)
1757
1758 EnumValue
1759 Enum(sso_struct) String(little-endian) Value(SSO_LITTLE_ENDIAN)
1760
1761 EnumValue
1762 Enum(sso_struct) String(native) Value(SSO_NATIVE)
1763
1764 fstats
1765 C++ ObjC++ Var(flag_detailed_statistics)
1766 Display statistics accumulated during compilation.
1767
1768 fstrict-enums
1769 C++ ObjC++ Optimization Var(flag_strict_enums)
1770 Assume that values of enumeration type are always within the minimum range of that type.
1771
1772 fstrict-prototype
1773 C++ ObjC++ Deprecated
1774
1775 fstrong-eval-order
1776 C++ ObjC++ Common Alias(fstrong-eval-order=, all, none)
1777 Follow the C++17 evaluation order requirements for assignment expressions,
1778 shift, member function calls, etc.
1779
1780 fstrong-eval-order=
1781 C++ ObjC++ Common Var(flag_strong_eval_order) Joined Enum(strong_eval_order) RejectNegative Init(-1)
1782 Follow the C++17 evaluation order requirements for assignment expressions,
1783 shift, member function calls, etc.
1784
1785 Enum
1786 Name(strong_eval_order) Type(int)
1787
1788 EnumValue
1789 Enum(strong_eval_order) String(none) Value(0)
1790
1791 EnumValue
1792 Enum(strong_eval_order) String(some) Value(1)
1793
1794 EnumValue
1795 Enum(strong_eval_order) String(all) Value(2)
1796
1797 ftabstop=
1798 C ObjC C++ ObjC++ Joined RejectNegative UInteger
1799 -ftabstop=<number>      Distance between tab stops for column reporting.
1800
1801 ftemplate-backtrace-limit=
1802 C++ ObjC++ Joined RejectNegative UInteger Var(template_backtrace_limit) Init(10)
1803 Set the maximum number of template instantiation notes for a single warning or error.
1804
1805 ftemplate-depth-
1806 C++ ObjC++ Joined RejectNegative Undocumented Alias(ftemplate-depth=)
1807
1808 ftemplate-depth=
1809 C++ ObjC++ Joined RejectNegative UInteger
1810 -ftemplate-depth=<number>       Specify maximum template instantiation depth.
1811
1812 fthis-is-variable
1813 C++ ObjC++ Deprecated
1814
1815 fthreadsafe-statics
1816 C++ ObjC++ Optimization Var(flag_threadsafe_statics) Init(1)
1817 -fno-threadsafe-statics Do not generate thread-safe code for initializing local statics.
1818
1819 funsigned-bitfields
1820 C ObjC C++ ObjC++ Var(flag_signed_bitfields, 0)
1821 When \"signed\" or \"unsigned\" is not given make the bitfield unsigned.
1822
1823 funsigned-char
1824 C ObjC C++ ObjC++ LTO Var(flag_signed_char, 0)
1825 Make \"char\" unsigned by default.
1826
1827 fuse-cxa-atexit
1828 C++ ObjC++ Var(flag_use_cxa_atexit) Init(DEFAULT_USE_CXA_ATEXIT)
1829 Use __cxa_atexit to register destructors.
1830
1831 fuse-cxa-get-exception-ptr
1832 C++ ObjC++ Var(flag_use_cxa_get_exception_ptr) Init(2)
1833 Use __cxa_get_exception_ptr in exception handling.
1834
1835 fvisibility-inlines-hidden
1836 C++ ObjC++
1837 Marks all inlined functions and methods as having hidden visibility.
1838
1839 fvisibility-ms-compat
1840 C++ ObjC++ Var(flag_visibility_ms_compat)
1841 Changes visibility to match Microsoft Visual Studio by default.
1842
1843 fvtable-gc
1844 C++ ObjC++ Deprecated
1845 No longer supported.
1846
1847 fvtable-thunks
1848 C++ ObjC++ Deprecated
1849 No longer supported.
1850
1851 fweak
1852 C++ ObjC++ Var(flag_weak) Init(1)
1853 Emit common-like symbols as weak symbols.
1854
1855 fwide-exec-charset=
1856 C ObjC C++ ObjC++ Joined RejectNegative
1857 -fwide-exec-charset=<cset>      Convert all wide strings and character constants to character set <cset>.
1858
1859 fworking-directory
1860 C ObjC C++ ObjC++ Var(flag_working_directory) Init(-1)
1861 Generate a #line directive pointing at the current working directory.
1862
1863 fxref
1864 C++ ObjC++ Deprecated
1865 No longer supported.
1866
1867 fzero-link
1868 ObjC ObjC++ Var(flag_zero_link)
1869 Generate lazy class lookup (via objc_getClass()) for use in Zero-Link mode.
1870
1871 gen-decls
1872 ObjC ObjC++ Driver Var(flag_gen_declaration) RejectNegative
1873 Dump declarations to a .decl file.
1874
1875 femit-struct-debug-baseonly
1876 C ObjC C++ ObjC++
1877 -femit-struct-debug-baseonly    Aggressive reduced debug info for structs.
1878
1879 femit-struct-debug-reduced
1880 C ObjC C++ ObjC++
1881 -femit-struct-debug-reduced     Conservative reduced debug info for structs.
1882
1883 femit-struct-debug-detailed=
1884 C ObjC C++ ObjC++ Joined
1885 -femit-struct-debug-detailed=<spec-list>        Detailed reduced debug info for structs.
1886
1887 fext-numeric-literals
1888 C++ ObjC++ Var(flag_ext_numeric_literals) Init(1)
1889 Interpret imaginary, fixed-point, or other gnu number suffix as the corresponding
1890 number literal rather than a user-defined number literal.
1891
1892 idirafter
1893 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
1894 -idirafter <dir>        Add <dir> to the end of the system include path.
1895
1896 imacros
1897 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing filename after %qs)
1898 -imacros <file> Accept definition of macros in <file>.
1899
1900 imultilib
1901 C ObjC C++ ObjC++ Joined Separate
1902 -imultilib <dir>        Set <dir> to be the multilib include subdirectory.
1903
1904 include
1905 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing filename after %qs)
1906 -include <file> Include the contents of <file> before other files.
1907
1908 iprefix
1909 C ObjC C++ ObjC++ Joined Separate
1910 -iprefix <path> Specify <path> as a prefix for next two options.
1911
1912 isysroot
1913 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
1914 -isysroot <dir> Set <dir> to be the system root directory.
1915
1916 isystem
1917 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
1918 -isystem <dir>  Add <dir> to the start of the system include path.
1919
1920 iquote
1921 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
1922 -iquote <dir>   Add <dir> to the end of the quote include path.
1923
1924 iwithprefix
1925 C ObjC C++ ObjC++ Joined Separate
1926 -iwithprefix <dir>      Add <dir> to the end of the system include path.
1927
1928 iwithprefixbefore
1929 C ObjC C++ ObjC++ Joined Separate
1930 -iwithprefixbefore <dir>        Add <dir> to the end of the main include path.
1931
1932 lang-asm
1933 C Undocumented RejectDriver
1934
1935 no-integrated-cpp
1936 Driver
1937
1938 nostdinc
1939 C ObjC C++ ObjC++
1940 Do not search standard system include directories (those specified with -isystem will still be used).
1941
1942 nostdinc++
1943 C++ ObjC++
1944 Do not search standard system include directories for C++.
1945
1946 o
1947 C ObjC C++ ObjC++ Joined Separate
1948 ; Documented in common.opt
1949
1950 pedantic
1951 C ObjC C++ ObjC++ Alias(Wpedantic)
1952 ; Documented in common.opt
1953
1954 print-objc-runtime-info
1955 ObjC ObjC++
1956 Generate C header of platform-specific features.
1957
1958 remap
1959 C ObjC C++ ObjC++
1960 Remap file names when including files.
1961
1962 std=c++98
1963 C++ ObjC++
1964 Conform to the ISO 1998 C++ standard revised by the 2003 technical corrigendum.
1965
1966 std=c++03
1967 C++ ObjC++ Alias(std=c++98)
1968 Conform to the ISO 1998 C++ standard revised by the 2003 technical corrigendum.
1969
1970 std=c++11
1971 C++ ObjC++
1972 Conform to the ISO 2011 C++ standard.
1973
1974 std=c++0x
1975 C++ ObjC++ Alias(std=c++11) Undocumented
1976 Deprecated in favor of -std=c++11.
1977
1978 std=c++1y
1979 C++ ObjC++ Alias(std=c++14) Undocumented
1980 Deprecated in favor of -std=c++14.
1981
1982 std=c++14
1983 C++ ObjC++
1984 Conform to the ISO 2014 C++ standard.
1985
1986 std=c++1z
1987 C++ ObjC++ Alias(std=c++17) Undocumented
1988 Deprecated in favor of -std=c++17.
1989
1990 std=c++17
1991 C++ ObjC++
1992 Conform to the ISO 2017 C++ standard.
1993
1994 std=c++2a
1995 C++ ObjC++
1996 Conform to the ISO 2020(?) C++ draft standard (experimental and incomplete support).
1997
1998 std=c11
1999 C ObjC
2000 Conform to the ISO 2011 C standard.
2001
2002 std=c1x
2003 C ObjC Alias(std=c11)
2004 Deprecated in favor of -std=c11.
2005
2006 std=c17
2007 C ObjC
2008 Conform to the ISO 2017 C standard (published in 2018).
2009
2010 std=c18
2011 C ObjC Alias(std=c17)
2012 Conform to the ISO 2017 C standard (published in 2018).
2013
2014 std=c2x
2015 C ObjC
2016 Conform to the ISO 202X C standard draft (experimental and incomplete support).
2017
2018 std=c89
2019 C ObjC Alias(std=c90)
2020 Conform to the ISO 1990 C standard.
2021
2022 std=c90
2023 C ObjC
2024 Conform to the ISO 1990 C standard.
2025
2026 std=c99
2027 C ObjC
2028 Conform to the ISO 1999 C standard.
2029
2030 std=c9x
2031 C ObjC Alias(std=c99)
2032 Deprecated in favor of -std=c99.
2033
2034 std=gnu++98
2035 C++ ObjC++
2036 Conform to the ISO 1998 C++ standard revised by the 2003 technical
2037 corrigendum with GNU extensions.
2038
2039 std=gnu++03
2040 C++ ObjC++ Alias(std=gnu++98)
2041 Conform to the ISO 1998 C++ standard revised by the 2003 technical
2042 corrigendum with GNU extensions.
2043
2044 std=gnu++11
2045 C++ ObjC++
2046 Conform to the ISO 2011 C++ standard with GNU extensions.
2047
2048 std=gnu++0x
2049 C++ ObjC++ Alias(std=gnu++11) Undocumented
2050 Deprecated in favor of -std=gnu++11.
2051
2052 std=gnu++1y
2053 C++ ObjC++ Alias(std=gnu++14) Undocumented
2054 Deprecated in favor of -std=gnu++14.
2055
2056 std=gnu++14
2057 C++ ObjC++
2058 Conform to the ISO 2014 C++ standard with GNU extensions.
2059
2060 std=gnu++1z
2061 C++ ObjC++ Alias(std=gnu++17) Undocumented
2062 Deprecated in favor of -std=gnu++17.
2063
2064 std=gnu++17
2065 C++ ObjC++
2066 Conform to the ISO 2017 C++ standard with GNU extensions.
2067
2068 std=gnu++2a
2069 C++ ObjC++
2070 Conform to the ISO 2020(?) C++ draft standard with GNU extensions (experimental and incomplete support).
2071
2072 std=gnu11
2073 C ObjC
2074 Conform to the ISO 2011 C standard with GNU extensions.
2075
2076 std=gnu1x
2077 C ObjC Alias(std=gnu11)
2078 Deprecated in favor of -std=gnu11.
2079
2080 std=gnu17
2081 C ObjC
2082 Conform to the ISO 2017 C standard (published in 2018) with GNU extensions.
2083
2084 std=gnu18
2085 C ObjC Alias(std=gnu17)
2086 Conform to the ISO 2017 C standard (published in 2018) with GNU extensions.
2087
2088 std=gnu2x
2089 C ObjC
2090 Conform to the ISO 202X C standard draft with GNU extensions (experimental and incomplete support).
2091
2092 std=gnu89
2093 C ObjC Alias(std=gnu90)
2094 Conform to the ISO 1990 C standard with GNU extensions.
2095
2096 std=gnu90
2097 C ObjC
2098 Conform to the ISO 1990 C standard with GNU extensions.
2099
2100 std=gnu99
2101 C ObjC
2102 Conform to the ISO 1999 C standard with GNU extensions.
2103
2104 std=gnu9x
2105 C ObjC Alias(std=gnu99)
2106 Deprecated in favor of -std=gnu99.
2107
2108 std=iso9899:1990
2109 C ObjC Alias(std=c90)
2110 Conform to the ISO 1990 C standard.
2111
2112 std=iso9899:199409
2113 C ObjC
2114 Conform to the ISO 1990 C standard as amended in 1994.
2115
2116 std=iso9899:1999
2117 C ObjC Alias(std=c99)
2118 Conform to the ISO 1999 C standard.
2119
2120 std=iso9899:199x
2121 C ObjC Alias(std=c99)
2122 Deprecated in favor of -std=iso9899:1999.
2123
2124 std=iso9899:2011
2125 C ObjC Alias(std=c11)
2126 Conform to the ISO 2011 C standard.
2127
2128 std=iso9899:2017
2129 C ObjC Alias(std=c17)
2130 Conform to the ISO 2017 C standard (published in 2018).
2131
2132 std=iso9899:2018
2133 C ObjC Alias(std=c17)
2134 Conform to the ISO 2017 C standard (published in 2018).
2135
2136 traditional
2137 Driver
2138
2139 traditional-cpp
2140 C ObjC C++ ObjC++
2141 Enable traditional preprocessing.
2142
2143 trigraphs
2144 C ObjC C++ ObjC++
2145 -trigraphs      Support ISO C trigraphs.
2146
2147 undef
2148 C ObjC C++ ObjC++ Var(flag_undef)
2149 Do not predefine system-specific and GCC-specific macros.
2150
2151 v
2152 C ObjC C++ ObjC++
2153 ; Documented in common.opt
2154
2155 w
2156 C ObjC C++ ObjC++
2157 ; Documented in common.opt
2158
2159 ; This comment is to ensure we retain the blank line above.