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8e8f6434 | 1 | @c Copyright (C) 2003-2018 Free Software Foundation, Inc. |
ff05e09e | 2 | @c This is part of the GCC manual. |
3 | @c For copying conditions, see the file gcc.texi. | |
4 | ||
5 | @node Options | |
6 | @chapter Option specification files | |
7 | @cindex option specification files | |
30b0f428 | 8 | @cindex @samp{optc-gen.awk} |
ff05e09e | 9 | |
10 | Most GCC command-line options are described by special option | |
11 | definition files, the names of which conventionally end in | |
12 | @code{.opt}. This chapter describes the format of these files. | |
13 | ||
14 | @menu | |
15 | * Option file format:: The general layout of the files | |
16 | * Option properties:: Supported option properties | |
17 | @end menu | |
18 | ||
19 | @node Option file format | |
20 | @section Option file format | |
21 | ||
22 | Option files are a simple list of records in which each field occupies | |
23 | its own line and in which the records themselves are separated by | |
24 | blank lines. Comments may appear on their own line anywhere within | |
25 | the file and are preceded by semicolons. Whitespace is allowed before | |
26 | the semicolon. | |
27 | ||
a9341855 | 28 | The files can contain the following types of record: |
ff05e09e | 29 | |
a9341855 | 30 | @itemize @bullet |
31 | @item | |
c24c5fac | 32 | A language definition record. These records have two fields: the |
33 | string @samp{Language} and the name of the language. Once a language | |
a9341855 | 34 | has been declared in this way, it can be used as an option property. |
ff05e09e | 35 | @xref{Option properties}. |
36 | ||
a9341855 | 37 | @item |
46f8e3b0 | 38 | A target specific save record to save additional information. These |
39 | records have two fields: the string @samp{TargetSave}, and a | |
40 | declaration type to go in the @code{cl_target_option} structure. | |
ff05e09e | 41 | |
0f8defe5 | 42 | @item |
43 | A variable record to define a variable used to store option | |
44 | information. These records have two fields: the string | |
45 | @samp{Variable}, and a declaration of the type and name of the | |
46 | variable, optionally with an initializer (but without any trailing | |
47 | @samp{;}). These records may be used for variables used for many | |
5461e683 | 48 | options where declaring the initializer in a single option definition |
49 | record, or duplicating it in many records, would be inappropriate, or | |
50 | for variables set in option handlers rather than referenced by | |
51 | @code{Var} properties. | |
0f8defe5 | 52 | |
755fa783 | 53 | @item |
54 | A variable record to define a variable used to store option | |
55 | information. These records have two fields: the string | |
56 | @samp{TargetVariable}, and a declaration of the type and name of the | |
57 | variable, optionally with an initializer (but without any trailing | |
58 | @samp{;}). @samp{TargetVariable} is a combination of @samp{Variable} | |
59 | and @samp{TargetSave} records in that the variable is defined in the | |
60 | @code{gcc_options} structure, but these variables are also stored in | |
61 | the @code{cl_target_option} structure. The variables are saved in the | |
62 | target save code and restored in the target restore code. | |
63 | ||
64 | @item | |
65 | A variable record to record any additional files that the | |
66 | @file{options.h} file should include. This is useful to provide | |
67 | enumeration or structure definitions needed for target variables. | |
68 | These records have two fields: the string @samp{HeaderInclude} and the | |
69 | name of the include file. | |
70 | ||
71 | @item | |
72 | A variable record to record any additional files that the | |
0bfbe373 | 73 | @file{options.c} or @file{options-save.c} file should include. This |
74 | is useful to provide | |
755fa783 | 75 | inline functions needed for target variables and/or @code{#ifdef} |
76 | sequences to properly set up the initialization. These records have | |
77 | two fields: the string @samp{SourceInclude} and the name of the | |
78 | include file. | |
79 | ||
d62a5950 | 80 | @item |
81 | An enumeration record to define a set of strings that may be used as | |
82 | arguments to an option or options. These records have three fields: | |
83 | the string @samp{Enum}, a space-separated list of properties and help | |
84 | text used to describe the set of strings in @option{--help} output. | |
85 | Properties use the same format as option properties; the following are | |
86 | valid: | |
87 | @table @code | |
88 | @item Name(@var{name}) | |
89 | This property is required; @var{name} must be a name (suitable for use | |
90 | in C identifiers) used to identify the set of strings in @code{Enum} | |
91 | option properties. | |
92 | ||
93 | @item Type(@var{type}) | |
94 | This property is required; @var{type} is the C type for variables set | |
95 | by options using this enumeration together with @code{Var}. | |
96 | ||
97 | @item UnknownError(@var{message}) | |
98 | The message @var{message} will be used as an error message if the | |
99 | argument is invalid; for enumerations without @code{UnknownError}, a | |
100 | generic error message is used. @var{message} should contain a single | |
101 | @samp{%qs} format, which will be used to format the invalid argument. | |
102 | @end table | |
103 | ||
104 | @item | |
105 | An enumeration value record to define one of the strings in a set | |
106 | given in an @samp{Enum} record. These records have two fields: the | |
107 | string @samp{EnumValue} and a space-separated list of properties. | |
108 | Properties use the same format as option properties; the following are | |
109 | valid: | |
110 | @table @code | |
111 | @item Enum(@var{name}) | |
112 | This property is required; @var{name} says which @samp{Enum} record | |
113 | this @samp{EnumValue} record corresponds to. | |
114 | ||
115 | @item String(@var{string}) | |
116 | This property is required; @var{string} is the string option argument | |
117 | being described by this record. | |
118 | ||
119 | @item Value(@var{value}) | |
120 | This property is required; it says what value (representable as | |
121 | @code{int}) should be used for the given string. | |
122 | ||
123 | @item Canonical | |
124 | This property is optional. If present, it says the present string is | |
125 | the canonical one among all those with the given value. Other strings | |
126 | yielding that value will be mapped to this one so specs do not need to | |
127 | handle them. | |
128 | ||
129 | @item DriverOnly | |
130 | This property is optional. If present, the present string will only | |
131 | be accepted by the driver. This is used for cases such as | |
132 | @option{-march=native} that are processed by the driver so that | |
133 | @samp{gcc -v} shows how the options chosen depended on the system on | |
134 | which the compiler was run. | |
135 | @end table | |
136 | ||
46f8e3b0 | 137 | @item |
a43fd3a5 | 138 | An option definition record. These records have the following fields: |
ff05e09e | 139 | @enumerate |
140 | @item | |
141 | the name of the option, with the leading ``-'' removed | |
142 | @item | |
143 | a space-separated list of option properties (@pxref{Option properties}) | |
144 | @item | |
145 | the help text to use for @option{--help} (omitted if the second field | |
146 | contains the @code{Undocumented} property). | |
147 | @end enumerate | |
148 | ||
149 | By default, all options beginning with ``f'', ``W'' or ``m'' are | |
150 | implicitly assumed to take a ``no-'' form. This form should not be | |
151 | listed separately. If an option beginning with one of these letters | |
152 | does not have a ``no-'' form, you can use the @code{RejectNegative} | |
153 | property to reject it. | |
154 | ||
155 | The help text is automatically line-wrapped before being displayed. | |
156 | Normally the name of the option is printed on the left-hand side of | |
157 | the output and the help text is printed on the right. However, if the | |
158 | help text contains a tab character, the text to the left of the tab is | |
159 | used instead of the option's name and the text to the right of the | |
160 | tab forms the help text. This allows you to elaborate on what type | |
161 | of argument the option takes. | |
162 | ||
a9341855 | 163 | @item |
c24c5fac | 164 | A target mask record. These records have one field of the form |
165 | @samp{Mask(@var{x})}. The options-processing script will automatically | |
a9341855 | 166 | allocate a bit in @code{target_flags} (@pxref{Run-time Target}) for |
167 | each mask name @var{x} and set the macro @code{MASK_@var{x}} to the | |
c24c5fac | 168 | appropriate bitmask. It will also declare a @code{TARGET_@var{x}} |
a9341855 | 169 | macro that has the value 1 when bit @code{MASK_@var{x}} is set and |
170 | 0 otherwise. | |
171 | ||
172 | They are primarily intended to declare target masks that are not | |
173 | associated with user options, either because these masks represent | |
174 | internal switches or because the options are not available on all | |
175 | configurations and yet the masks always need to be defined. | |
176 | @end itemize | |
177 | ||
ff05e09e | 178 | @node Option properties |
179 | @section Option properties | |
180 | ||
65441c28 | 181 | The second field of an option record can specify any of the following |
b6a556f8 | 182 | properties. When an option takes an argument, it is enclosed in parentheses |
65441c28 | 183 | following the option property name. The parser that handles option files |
184 | is quite simplistic, and will be tricked by any nested parentheses within | |
185 | the argument text itself; in this case, the entire option argument can | |
186 | be wrapped in curly braces within the parentheses to demarcate it, e.g.: | |
187 | ||
188 | @smallexample | |
189 | Condition(@{defined (USE_CYGWIN_LIBSTDCXX_WRAPPERS)@}) | |
190 | @end smallexample | |
ff05e09e | 191 | |
192 | @table @code | |
193 | @item Common | |
194 | The option is available for all languages and targets. | |
195 | ||
196 | @item Target | |
197 | The option is available for all languages but is target-specific. | |
198 | ||
e28aa114 | 199 | @item Driver |
200 | The option is handled by the compiler driver using code not shared | |
201 | with the compilers proper (@file{cc1} etc.). | |
202 | ||
ff05e09e | 203 | @item @var{language} |
204 | The option is available when compiling for the given language. | |
205 | ||
206 | It is possible to specify several different languages for the same | |
207 | option. Each @var{language} must have been declared by an earlier | |
208 | @code{Language} record. @xref{Option file format}. | |
209 | ||
e28aa114 | 210 | @item RejectDriver |
211 | The option is only handled by the compilers proper (@file{cc1} etc.)@: | |
212 | and should not be accepted by the driver. | |
213 | ||
ff05e09e | 214 | @item RejectNegative |
215 | The option does not have a ``no-'' form. All options beginning with | |
216 | ``f'', ``W'' or ``m'' are assumed to have a ``no-'' form unless this | |
217 | property is used. | |
218 | ||
a91c04b7 | 219 | @item Negative(@var{othername}) |
68576faf | 220 | The option will turn off another option @var{othername}, which is |
a91c04b7 | 221 | the option name with the leading ``-'' removed. This chain action will |
222 | propagate through the @code{Negative} property of the option to be | |
223 | turned off. | |
224 | ||
d98c9552 | 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 | ||
ff05e09e | 232 | @item Joined |
233 | @itemx Separate | |
234 | The option takes a mandatory argument. @code{Joined} indicates | |
235 | that the option and argument can be included in the same @code{argv} | |
236 | entry (as with @code{-mflush-func=@var{name}}, for example). | |
237 | @code{Separate} indicates that the option and argument can be | |
238 | separate @code{argv} entries (as with @code{-o}). An option is | |
239 | allowed to have both of these properties. | |
240 | ||
241 | @item JoinedOrMissing | |
242 | The option takes an optional argument. If the argument is given, | |
243 | it will be part of the same @code{argv} entry as the option itself. | |
244 | ||
245 | This property cannot be used alongside @code{Joined} or @code{Separate}. | |
246 | ||
fecf9011 | 247 | @item MissingArgError(@var{message}) |
248 | For an option marked @code{Joined} or @code{Separate}, the message | |
249 | @var{message} will be used as an error message if the mandatory | |
250 | argument is missing; for options without @code{MissingArgError}, a | |
251 | generic error message is used. @var{message} should contain a single | |
252 | @samp{%qs} format, which will be used to format the name of the option | |
253 | passed. | |
254 | ||
e2028bfa | 255 | @item Args(@var{n}) |
256 | For an option marked @code{Separate}, indicate that it takes @var{n} | |
257 | arguments. The default is 1. | |
258 | ||
ff05e09e | 259 | @item UInteger |
8e18705e | 260 | The option's argument is a non-negative integer consisting of either |
261 | decimal or hexadecimal digits interpreted as @code{int}. Hexadecimal | |
262 | integers may optionally start with the @code{0x} or @code{0X} prefix. | |
263 | The option parser validates and converts the argument before passing | |
264 | it to the relevant option handler. @code{UInteger} should also be used | |
265 | with options like @code{-falign-loops} where both @code{-falign-loops} | |
266 | and @code{-falign-loops}=@var{n} are supported to make sure the saved | |
267 | options are given a full integer. Positive values of the argument in | |
268 | excess of @code{INT_MAX} wrap around zero. | |
269 | ||
270 | @item Host_Wide_Int | |
271 | The option's argument is a non-negative integer consisting of either | |
272 | decimal or hexadecimal digits interpreted as the widest integer type | |
273 | on the host. As with an @code{UInteger} argument, hexadecimal integers | |
274 | may optionally start with the @code{0x} or @code{0X} prefix. The option | |
275 | parser validates and converts the argument before passing it to | |
276 | the relevant option handler. @code{Host_Wide_Int} should be used with | |
277 | options that need to accept very large values. Positive values of | |
278 | the argument in excess of @code{HOST_WIDE_INT_M1U} are assigned | |
279 | @code{HOST_WIDE_INT_M1U}. | |
ff05e09e | 280 | |
899c70cd | 281 | @item IntegerRange(@var{n}, @var{m}) |
8e18705e | 282 | The options's arguments are integers of type @code{int}. The option's |
283 | parser validates that the value of an option integer argument is within | |
284 | the closed range [@var{n}, @var{m}]. | |
285 | ||
286 | @item ByteSize | |
287 | A property applicable only to @code{UInteger} or @code{Host_Wide_Int} | |
288 | arguments. The option's integer argument is interpreted as if in infinite | |
289 | precision using saturation arithmetic in the corresponding type. The argument | |
290 | may be followed by a @samp{byte-size} suffix designating a multiple of bytes | |
291 | such as @code{kB} and @code{KiB} for kilobyte and kibibyte, respectively, | |
292 | @code{MB} and @code{MiB} for megabyte and mebibyte, @code{GB} and @code{GiB} | |
293 | for gigabyte and gigibyte, and so on. @code{ByteSize} should be used for | |
294 | with options that take a very large argument representing a size in bytes, | |
295 | such as @option{-Wlarger-than=}. | |
899c70cd | 296 | |
cb14e058 | 297 | @item ToLower |
298 | The option's argument should be converted to lowercase as part of | |
299 | putting it in canonical form, and before comparing with the strings | |
300 | indicated by any @code{Enum} property. | |
301 | ||
89c69892 | 302 | @item NoDriverArg |
303 | For an option marked @code{Separate}, the option only takes an | |
304 | argument in the compiler proper, not in the driver. This is for | |
305 | compatibility with existing options that are used both directly and | |
306 | via @option{-Wp,}; new options should not have this property. | |
307 | ||
ff05e09e | 308 | @item Var(@var{var}) |
5461e683 | 309 | The state of this option should be stored in variable @var{var} |
310 | (actually a macro for @code{global_options.x_@var{var}}). | |
0fe44c73 | 311 | The way that the state is stored depends on the type of option: |
312 | ||
274d31f0 | 313 | @item Deprecated |
314 | The option is deprecated and every usage of such option will | |
315 | result in a warning. | |
316 | ||
0fe44c73 | 317 | @itemize @bullet |
318 | @item | |
319 | If the option uses the @code{Mask} or @code{InverseMask} properties, | |
320 | @var{var} is the integer variable that contains the mask. | |
321 | ||
322 | @item | |
323 | If the option is a normal on/off switch, @var{var} is an integer | |
324 | variable that is nonzero when the option is enabled. The options | |
325 | parser will set the variable to 1 when the positive form of the | |
326 | option is used and 0 when the ``no-'' form is used. | |
327 | ||
328 | @item | |
329 | If the option takes an argument and has the @code{UInteger} property, | |
330 | @var{var} is an integer variable that stores the value of the argument. | |
331 | ||
d62a5950 | 332 | @item |
333 | If the option takes an argument and has the @code{Enum} property, | |
334 | @var{var} is a variable (type given in the @code{Type} property of the | |
335 | @samp{Enum} record whose @code{Name} property has the same argument as | |
336 | the @code{Enum} property of this option) that stores the value of the | |
337 | argument. | |
338 | ||
f0da0668 | 339 | @item |
340 | If the option has the @code{Defer} property, @var{var} is a pointer to | |
341 | a @code{VEC(cl_deferred_option,heap)} that stores the option for later | |
342 | processing. (@var{var} is declared with type @code{void *} and needs | |
343 | to be cast to @code{VEC(cl_deferred_option,heap)} before use.) | |
344 | ||
0fe44c73 | 345 | @item |
346 | Otherwise, if the option takes an argument, @var{var} is a pointer to | |
347 | the argument string. The pointer will be null if the argument is optional | |
348 | and wasn't given. | |
349 | @end itemize | |
ff05e09e | 350 | |
5461e683 | 351 | The option-processing script will usually zero-initialize @var{var}. |
352 | You can modify this behavior using @code{Init}. | |
ff05e09e | 353 | |
354 | @item Var(@var{var}, @var{set}) | |
355 | The option controls an integer variable @var{var} and is active when | |
356 | @var{var} equals @var{set}. The option parser will set @var{var} to | |
357 | @var{set} when the positive form of the option is used and @code{!@var{set}} | |
358 | when the ``no-'' form is used. | |
359 | ||
360 | @var{var} is declared in the same way as for the single-argument form | |
361 | described above. | |
362 | ||
ff05e09e | 363 | @item Init(@var{value}) |
364 | The variable specified by the @code{Var} property should be statically | |
5461e683 | 365 | initialized to @var{value}. If more than one option using the same |
366 | variable specifies @code{Init}, all must specify the same initializer. | |
ff05e09e | 367 | |
368 | @item Mask(@var{name}) | |
c5e839cb | 369 | The option is associated with a bit in the @code{target_flags} |
370 | variable (@pxref{Run-time Target}) and is active when that bit is set. | |
371 | You may also specify @code{Var} to select a variable other than | |
372 | @code{target_flags}. | |
373 | ||
374 | The options-processing script will automatically allocate a unique bit | |
375 | for the option. If the option is attached to @samp{target_flags}, | |
376 | the script will set the macro @code{MASK_@var{name}} to the appropriate | |
377 | bitmask. It will also declare a @code{TARGET_@var{name}} macro that has | |
378 | the value 1 when the option is active and 0 otherwise. If you use @code{Var} | |
66da3ba4 | 379 | to attach the option to a different variable, the bitmask macro with be |
380 | called @code{OPTION_MASK_@var{name}}. | |
c5e839cb | 381 | |
ff05e09e | 382 | @item InverseMask(@var{othername}) |
383 | @itemx InverseMask(@var{othername}, @var{thisname}) | |
384 | The option is the inverse of another option that has the | |
385 | @code{Mask(@var{othername})} property. If @var{thisname} is given, | |
386 | the options-processing script will declare a @code{TARGET_@var{thisname}} | |
387 | macro that is 1 when the option is active and 0 otherwise. | |
388 | ||
d62a5950 | 389 | @item Enum(@var{name}) |
390 | The option's argument is a string from the set of strings associated | |
391 | with the corresponding @samp{Enum} record. The string is checked and | |
392 | converted to the integer specified in the corresponding | |
393 | @samp{EnumValue} record before being passed to option handlers. | |
394 | ||
f0da0668 | 395 | @item Defer |
396 | The option should be stored in a vector, specified with @code{Var}, | |
397 | for later processing. | |
398 | ||
67089c6b | 399 | @item Alias(@var{opt}) |
400 | @itemx Alias(@var{opt}, @var{arg}) | |
401 | @itemx Alias(@var{opt}, @var{posarg}, @var{negarg}) | |
4e775b8e | 402 | The option is an alias for @option{-@var{opt}} (or the negative form |
403 | of that option, depending on @code{NegativeAlias}). In the first form, | |
67089c6b | 404 | any argument passed to the alias is considered to be passed to |
405 | @option{-@var{opt}}, and @option{-@var{opt}} is considered to be | |
406 | negated if the alias is used in negated form. In the second form, the | |
407 | alias may not be negated or have an argument, and @var{posarg} is | |
408 | considered to be passed as an argument to @option{-@var{opt}}. In the | |
409 | third form, the alias may not have an argument, if the alias is used | |
410 | in the positive form then @var{posarg} is considered to be passed to | |
411 | @option{-@var{opt}}, and if the alias is used in the negative form | |
412 | then @var{negarg} is considered to be passed to @option{-@var{opt}}. | |
413 | ||
414 | Aliases should not specify @code{Var} or @code{Mask} or | |
415 | @code{UInteger}. Aliases should normally specify the same languages | |
416 | as the target of the alias; the flags on the target will be used to | |
417 | determine any diagnostic for use of an option for the wrong language, | |
418 | while those on the alias will be used to identify what command-line | |
419 | text is the option and what text is any argument to that option. | |
420 | ||
421 | When an @code{Alias} definition is used for an option, driver specs do | |
422 | not need to handle it and no @samp{OPT_} enumeration value is defined | |
423 | for it; only the canonical form of the option will be seen in those | |
424 | places. | |
425 | ||
4e775b8e | 426 | @item NegativeAlias |
427 | For an option marked with @code{Alias(@var{opt})}, the option is | |
428 | considered to be an alias for the positive form of @option{-@var{opt}} | |
429 | if negated and for the negative form of @option{-@var{opt}} if not | |
430 | negated. @code{NegativeAlias} may not be used with the forms of | |
431 | @code{Alias} taking more than one argument. | |
432 | ||
3b0273a1 | 433 | @item Ignore |
434 | This option is ignored apart from printing any warning specified using | |
435 | @code{Warn}. The option will not be seen by specs and no @samp{OPT_} | |
436 | enumeration value is defined for it. | |
437 | ||
0b1d266f | 438 | @item SeparateAlias |
439 | For an option marked with @code{Joined}, @code{Separate} and | |
440 | @code{Alias}, the option only acts as an alias when passed a separate | |
441 | argument; with a joined argument it acts as a normal option, with an | |
442 | @samp{OPT_} enumeration value. This is for compatibility with the | |
443 | Java @option{-d} option and should not be used for new options. | |
444 | ||
3b0273a1 | 445 | @item Warn(@var{message}) |
446 | If this option is used, output the warning @var{message}. | |
447 | @var{message} is a format string, either taking a single operand with | |
448 | a @samp{%qs} format which is the option name, or not taking any | |
449 | operands, which is passed to the @samp{warning} function. If an alias | |
450 | is marked @code{Warn}, the target of the alias must not also be marked | |
451 | @code{Warn}. | |
452 | ||
ff05e09e | 453 | @item Report |
454 | The state of the option should be printed by @option{-fverbose-asm}. | |
455 | ||
d27c69c9 | 456 | @item Warning |
457 | This is a warning option and should be shown as such in | |
458 | @option{--help} output. This flag does not currently affect anything | |
459 | other than @option{--help}. | |
460 | ||
461 | @item Optimization | |
462 | This is an optimization option. It should be shown as such in | |
463 | @option{--help} output, and any associated variable named using | |
464 | @code{Var} should be saved and restored when the optimization level is | |
465 | changed with @code{optimize} attributes. | |
466 | ||
05d8c5f8 | 467 | @item PerFunction |
468 | This is an option that can be overridden on a per-function basis. | |
469 | @code{Optimization} implies @code{PerFunction}, but options that do not | |
470 | affect executable code generation may use this flag instead, so that the | |
471 | option is not taken into account in ways that might affect executable | |
472 | code generation. | |
473 | ||
ff05e09e | 474 | @item Undocumented |
475 | The option is deliberately missing documentation and should not | |
476 | be included in the @option{--help} output. | |
5c5ccba2 | 477 | |
478 | @item Condition(@var{cond}) | |
479 | The option should only be accepted if preprocessor condition | |
480 | @var{cond} is true. Note that any C declarations associated with the | |
481 | option will be present even if @var{cond} is false; @var{cond} simply | |
482 | controls whether the option is accepted and whether it is printed in | |
483 | the @option{--help} output. | |
46f8e3b0 | 484 | |
485 | @item Save | |
486 | Build the @code{cl_target_option} structure to hold a copy of the | |
487 | option, add the functions @code{cl_target_option_save} and | |
488 | @code{cl_target_option_restore} to save and restore the options. | |
ecee1b29 | 489 | |
490 | @item SetByCombined | |
491 | The option may also be set by a combined option such as | |
492 | @option{-ffast-math}. This causes the @code{gcc_options} struct to | |
493 | have a field @code{frontend_set_@var{name}}, where @code{@var{name}} | |
494 | is the name of the field holding the value of this option (without the | |
495 | leading @code{x_}). This gives the front end a way to indicate that | |
496 | the value has been set explicitly and should not be changed by the | |
497 | combined option. For example, some front ends use this to prevent | |
498 | @option{-ffast-math} and @option{-fno-fast-math} from changing the | |
499 | value of @option{-fmath-errno} for languages that do not use | |
500 | @code{errno}. | |
501 | ||
fbb6fbd8 | 502 | @item EnabledBy(@var{opt}) |
1eaf1dbe | 503 | @itemx EnabledBy(@var{opt} || @var{opt2}) |
1090f26f | 504 | @itemx EnabledBy(@var{opt} && @var{opt2}) |
505 | If not explicitly set, the option is set to the value of | |
1eaf1dbe | 506 | @option{-@var{opt}}; multiple options can be given, separated by |
507 | @code{||}. The third form using @code{&&} specifies that the option is | |
5463f502 | 508 | only set if both @var{opt} and @var{opt2} are set. The options @var{opt} |
509 | and @var{opt2} must have the @code{Common} property; otherwise, use | |
510 | @code{LangEnabledBy}. | |
d3b7ee7c | 511 | |
512 | @item LangEnabledBy(@var{language}, @var{opt}) | |
77b27208 | 513 | @itemx LangEnabledBy(@var{language}, @var{opt}, @var{posarg}, @var{negarg}) |
d3b7ee7c | 514 | When compiling for the given language, the option is set to the value |
1eaf1dbe | 515 | of @option{-@var{opt}}, if not explicitly set. @var{opt} can be also a list |
516 | of @code{||} separated options. In the second form, if | |
77b27208 | 517 | @var{opt} is used in the positive form then @var{posarg} is considered |
518 | to be passed to the option, and if @var{opt} is used in the negative | |
519 | form then @var{negarg} is considered to be passed to the option. It | |
520 | is possible to specify several different languages. Each | |
521 | @var{language} must have been declared by an earlier @code{Language} | |
522 | record. @xref{Option file format}. | |
3fe1aabe | 523 | |
524 | @item NoDWARFRecord | |
525 | The option is omitted from the producer string written by | |
526 | @option{-grecord-gcc-switches}. | |
d8f2baf5 | 527 | |
528 | @item PchIgnore | |
529 | Even if this is a target option, this option will not be recorded / compared | |
530 | to determine if a precompiled header file matches. | |
3636964b | 531 | |
532 | @item CPP(@var{var}) | |
533 | The state of this option should be kept in sync with the preprocessor | |
04afd878 | 534 | option @var{var}. If this property is set, then properties @code{Var} |
535 | and @code{Init} must be set as well. | |
3636964b | 536 | |
7ff8db31 | 537 | @item CppReason(@var{CPP_W_Enum}) |
538 | This warning option corresponds to @code{cpplib.h} warning reason code | |
539 | @var{CPP_W_Enum}. This should only be used for warning options of the | |
540 | C-family front-ends. | |
541 | ||
ff05e09e | 542 | @end table |