gcc/c-family/c.opt

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