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gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900
parents f6334be47118
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1 @c Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 1 @c Copyright (C) 2003-2017 Free Software Foundation, Inc.
2 @c Free Software Foundation, Inc.
3 @c This is part of the GCC manual. 2 @c This is part of the GCC manual.
4 @c For copying conditions, see the file gcc.texi. 3 @c For copying conditions, see the file gcc.texi.
5 4
6 @node Options 5 @node Options
7 @chapter Option specification files 6 @chapter Option specification files
69 These records have two fields: the string @samp{HeaderInclude} and the 68 These records have two fields: the string @samp{HeaderInclude} and the
70 name of the include file. 69 name of the include file.
71 70
72 @item 71 @item
73 A variable record to record any additional files that the 72 A variable record to record any additional files that the
74 @file{options.c} file should include. This is useful to provide 73 @file{options.c} or @file{options-save.c} file should include. This
74 is useful to provide
75 inline functions needed for target variables and/or @code{#ifdef} 75 inline functions needed for target variables and/or @code{#ifdef}
76 sequences to properly set up the initialization. These records have 76 sequences to properly set up the initialization. These records have
77 two fields: the string @samp{SourceInclude} and the name of the 77 two fields: the string @samp{SourceInclude} and the name of the
78 include file. 78 include file.
79 79
220 The option will turn off another option @var{othername}, which is 220 The option will turn off another option @var{othername}, which is
221 the option name with the leading ``-'' removed. This chain action will 221 the option name with the leading ``-'' removed. This chain action will
222 propagate through the @code{Negative} property of the option to be 222 propagate through the @code{Negative} property of the option to be
223 turned off. 223 turned off.
224 224
225 As a consequence, if you have a group of mutually-exclusive
226 options, their @code{Negative} properties should form a circular chain.
227 For example, if options @option{-@var{a}}, @option{-@var{b}} and
228 @option{-@var{c}} are mutually exclusive, their respective @code{Negative}
229 properties should be @samp{Negative(@var{b})}, @samp{Negative(@var{c})}
230 and @samp{Negative(@var{a})}.
231
225 @item Joined 232 @item Joined
226 @itemx Separate 233 @itemx Separate
227 The option takes a mandatory argument. @code{Joined} indicates 234 The option takes a mandatory argument. @code{Joined} indicates
228 that the option and argument can be included in the same @code{argv} 235 that the option and argument can be included in the same @code{argv}
229 entry (as with @code{-mflush-func=@var{name}}, for example). 236 entry (as with @code{-mflush-func=@var{name}}, for example).
255 option handler. @code{UInteger} should also be used on options like 262 option handler. @code{UInteger} should also be used on options like
256 @code{-falign-loops} where both @code{-falign-loops} and 263 @code{-falign-loops} where both @code{-falign-loops} and
257 @code{-falign-loops}=@var{n} are supported to make sure the saved 264 @code{-falign-loops}=@var{n} are supported to make sure the saved
258 options are given a full integer. 265 options are given a full integer.
259 266
267 @item ToLower
268 The option's argument should be converted to lowercase as part of
269 putting it in canonical form, and before comparing with the strings
270 indicated by any @code{Enum} property.
271
260 @item NoDriverArg 272 @item NoDriverArg
261 For an option marked @code{Separate}, the option only takes an 273 For an option marked @code{Separate}, the option only takes an
262 argument in the compiler proper, not in the driver. This is for 274 argument in the compiler proper, not in the driver. This is for
263 compatibility with existing options that are used both directly and 275 compatibility with existing options that are used both directly and
264 via @option{-Wp,}; new options should not have this property. 276 via @option{-Wp,}; new options should not have this property.
328 The options-processing script will automatically allocate a unique bit 340 The options-processing script will automatically allocate a unique bit
329 for the option. If the option is attached to @samp{target_flags}, 341 for the option. If the option is attached to @samp{target_flags},
330 the script will set the macro @code{MASK_@var{name}} to the appropriate 342 the script will set the macro @code{MASK_@var{name}} to the appropriate
331 bitmask. It will also declare a @code{TARGET_@var{name}} macro that has 343 bitmask. It will also declare a @code{TARGET_@var{name}} macro that has
332 the value 1 when the option is active and 0 otherwise. If you use @code{Var} 344 the value 1 when the option is active and 0 otherwise. If you use @code{Var}
333 to attach the option to a different variable, the associated macros are 345 to attach the option to a different variable, the bitmask macro with be
334 called @code{OPTION_MASK_@var{name}} and @code{OPTION_@var{name}} respectively. 346 called @code{OPTION_MASK_@var{name}}.
335
336 You can disable automatic bit allocation using @code{MaskExists}.
337 347
338 @item InverseMask(@var{othername}) 348 @item InverseMask(@var{othername})
339 @itemx InverseMask(@var{othername}, @var{thisname}) 349 @itemx InverseMask(@var{othername}, @var{thisname})
340 The option is the inverse of another option that has the 350 The option is the inverse of another option that has the
341 @code{Mask(@var{othername})} property. If @var{thisname} is given, 351 @code{Mask(@var{othername})} property. If @var{thisname} is given,
342 the options-processing script will declare a @code{TARGET_@var{thisname}} 352 the options-processing script will declare a @code{TARGET_@var{thisname}}
343 macro that is 1 when the option is active and 0 otherwise. 353 macro that is 1 when the option is active and 0 otherwise.
344 354
345 @item MaskExists
346 The mask specified by the @code{Mask} property already exists.
347 No @code{MASK} or @code{TARGET} definitions should be added to
348 @file{options.h} in response to this option record.
349
350 The main purpose of this property is to support synonymous options.
351 The first option should use @samp{Mask(@var{name})} and the others
352 should use @samp{Mask(@var{name}) MaskExists}.
353
354 @item Enum(@var{name}) 355 @item Enum(@var{name})
355 The option's argument is a string from the set of strings associated 356 The option's argument is a string from the set of strings associated
356 with the corresponding @samp{Enum} record. The string is checked and 357 with the corresponding @samp{Enum} record. The string is checked and
357 converted to the integer specified in the corresponding 358 converted to the integer specified in the corresponding
358 @samp{EnumValue} record before being passed to option handlers. 359 @samp{EnumValue} record before being passed to option handlers.
362 for later processing. 363 for later processing.
363 364
364 @item Alias(@var{opt}) 365 @item Alias(@var{opt})
365 @itemx Alias(@var{opt}, @var{arg}) 366 @itemx Alias(@var{opt}, @var{arg})
366 @itemx Alias(@var{opt}, @var{posarg}, @var{negarg}) 367 @itemx Alias(@var{opt}, @var{posarg}, @var{negarg})
367 The option is an alias for @option{-@var{opt}}. In the first form, 368 The option is an alias for @option{-@var{opt}} (or the negative form
369 of that option, depending on @code{NegativeAlias}). In the first form,
368 any argument passed to the alias is considered to be passed to 370 any argument passed to the alias is considered to be passed to
369 @option{-@var{opt}}, and @option{-@var{opt}} is considered to be 371 @option{-@var{opt}}, and @option{-@var{opt}} is considered to be
370 negated if the alias is used in negated form. In the second form, the 372 negated if the alias is used in negated form. In the second form, the
371 alias may not be negated or have an argument, and @var{posarg} is 373 alias may not be negated or have an argument, and @var{posarg} is
372 considered to be passed as an argument to @option{-@var{opt}}. In the 374 considered to be passed as an argument to @option{-@var{opt}}. In the
385 When an @code{Alias} definition is used for an option, driver specs do 387 When an @code{Alias} definition is used for an option, driver specs do
386 not need to handle it and no @samp{OPT_} enumeration value is defined 388 not need to handle it and no @samp{OPT_} enumeration value is defined
387 for it; only the canonical form of the option will be seen in those 389 for it; only the canonical form of the option will be seen in those
388 places. 390 places.
389 391
392 @item NegativeAlias
393 For an option marked with @code{Alias(@var{opt})}, the option is
394 considered to be an alias for the positive form of @option{-@var{opt}}
395 if negated and for the negative form of @option{-@var{opt}} if not
396 negated. @code{NegativeAlias} may not be used with the forms of
397 @code{Alias} taking more than one argument.
398
390 @item Ignore 399 @item Ignore
391 This option is ignored apart from printing any warning specified using 400 This option is ignored apart from printing any warning specified using
392 @code{Warn}. The option will not be seen by specs and no @samp{OPT_} 401 @code{Warn}. The option will not be seen by specs and no @samp{OPT_}
393 enumeration value is defined for it. 402 enumeration value is defined for it.
394 403
418 @item Optimization 427 @item Optimization
419 This is an optimization option. It should be shown as such in 428 This is an optimization option. It should be shown as such in
420 @option{--help} output, and any associated variable named using 429 @option{--help} output, and any associated variable named using
421 @code{Var} should be saved and restored when the optimization level is 430 @code{Var} should be saved and restored when the optimization level is
422 changed with @code{optimize} attributes. 431 changed with @code{optimize} attributes.
432
433 @item PerFunction
434 This is an option that can be overridden on a per-function basis.
435 @code{Optimization} implies @code{PerFunction}, but options that do not
436 affect executable code generation may use this flag instead, so that the
437 option is not taken into account in ways that might affect executable
438 code generation.
423 439
424 @item Undocumented 440 @item Undocumented
425 The option is deliberately missing documentation and should not 441 The option is deliberately missing documentation and should not
426 be included in the @option{--help} output. 442 be included in the @option{--help} output.
427 443
447 combined option. For example, some front ends use this to prevent 463 combined option. For example, some front ends use this to prevent
448 @option{-ffast-math} and @option{-fno-fast-math} from changing the 464 @option{-ffast-math} and @option{-fno-fast-math} from changing the
449 value of @option{-fmath-errno} for languages that do not use 465 value of @option{-fmath-errno} for languages that do not use
450 @code{errno}. 466 @code{errno}.
451 467
468 @item EnabledBy(@var{opt})
469 @itemx EnabledBy(@var{opt} || @var{opt2})
470 @itemx EnabledBy(@var{opt} && @var{opt2})
471 If not explicitly set, the option is set to the value of
472 @option{-@var{opt}}; multiple options can be given, separated by
473 @code{||}. The third form using @code{&&} specifies that the option is
474 only set if both @var{opt} and @var{opt2} are set. The options @var{opt}
475 and @var{opt2} must have the @code{Common} property; otherwise, use
476 @code{LangEnabledBy}.
477
478 @item LangEnabledBy(@var{language}, @var{opt})
479 @itemx LangEnabledBy(@var{language}, @var{opt}, @var{posarg}, @var{negarg})
480 When compiling for the given language, the option is set to the value
481 of @option{-@var{opt}}, if not explicitly set. @var{opt} can be also a list
482 of @code{||} separated options. In the second form, if
483 @var{opt} is used in the positive form then @var{posarg} is considered
484 to be passed to the option, and if @var{opt} is used in the negative
485 form then @var{negarg} is considered to be passed to the option. It
486 is possible to specify several different languages. Each
487 @var{language} must have been declared by an earlier @code{Language}
488 record. @xref{Option file format}.
489
490 @item NoDWARFRecord
491 The option is omitted from the producer string written by
492 @option{-grecord-gcc-switches}.
493
494 @item PchIgnore
495 Even if this is a target option, this option will not be recorded / compared
496 to determine if a precompiled header file matches.
497
498 @item CPP(@var{var})
499 The state of this option should be kept in sync with the preprocessor
500 option @var{var}. If this property is set, then properties @code{Var}
501 and @code{Init} must be set as well.
502
503 @item CppReason(@var{CPP_W_Enum})
504 This warning option corresponds to @code{cpplib.h} warning reason code
505 @var{CPP_W_Enum}. This should only be used for warning options of the
506 C-family front-ends.
507
452 @end table 508 @end table