1 .\" Process with groff -man -Tascii file.3
2 .TH GMQCC 1 2012-07-12 "" "gmqcc Manual"
4 gmqcc \- A Quake C compiler built from the NIH realm of sarcastic wit
7 [\fIOPTIONS\fR] [\fIfiles...\fR]
9 Traditionally, a QC compiler reads the file \fIprogs.src\fR which
10 in its first line contains the output filename, and the rest is a
11 list of QC source files that are to be compiled in order.
12 \fBgmqcc\fR optionally takes options to specify the output and
13 input files on the commandline, and also accepts assembly files.
15 \fBgmqcc\fR mostly tries to mimic gcc's commandline handling, though
16 there are also traditional long-options available.
19 Show a usage message and exit.
22 Turn on some compiler debugging mechanisms.
25 Turn on compiler mem-check. (Shows allocations and checks for leaks.)
27 .BI "-o, --output=" filename
28 Specify the output filename. Defaults to progs.dat. This will overwrite
29 the output file listed in a \fIprogs.src\fR file in case such a file is used.
32 Specify the optimization level
35 Highest optimization level
37 Default optimization level
39 Minimal optimization level
41 Disable optimization entirely
44 .BI "-O" name "\fR, " "" -Ono- name
45 Enable or disable a specific optimization. Note that these options
46 must be used after setting the optimization level, otherwise they'll
50 List all possible optimizations and the optimization level they're
54 Be less verbose. In particular removes the messages about which files
55 are being processed, and which compilation mode is being used, and
56 some others. Warnings and errors will of course still be displayed.
58 .BI -W warning "\fR, " "" -Wno- warning
59 Enable or disable a warning.
62 Enable all warnings. Overrides preceding -W parameters.
64 .BR -Werror ", " -Wno-error
65 Controls whether or not all warnings should be treated as errors.
67 .BI -Werror- warning "\fR, " "" -Wno-error- warning
68 Controls whether a specific warning should be an error.
71 List all possible warn flags.
73 .BI -f flag "\fR, " "" -fno- flag
74 Enable or disable a specific compile flag. See the list of flags
78 List all possible compile flags.
81 Disables colored output
84 Use an ini file to read all the -O, -W and -f flag from. See the
85 CONFIG section about the file format.
88 Redirects standard output to a \fIfile\fR
91 Redirects standard error to a \fIfile\fR
94 Use the specified standard for parsing QC code. The following standards
96 .IR gmqcc , qcc , fteqcc
97 Selecting a standard also implies some -f options and behaves as if
98 those options have been written right after the -std option, meaning
99 if you changed them before the -std option, you're now overwriting
102 .BR -std=gmqcc " includes:"
104 -fadjust-vector-fields
106 .BR -std=qcc " includes:"
109 -fassign-function-types
110 -f\fIno-\fRadjust-vector-fields
113 .BR -std=fteqcc " includes:"
117 -ftranslatable-strings
118 -fassign-function-types
120 -f\fIno-\fRadjust-vector-fields
121 -f\fIno-\fRcorrect-ternary
126 DEBUG OPTION. Print the code's intermediate representation before the
127 optimization and finalization passes to stdout before generating the
131 DEBUG OPTION. Print the code's intermediate representation after the
132 optimization and finalization passes to stdout before generating the
133 binary. The instructions will be enumerated, and values will contain a
138 Generate a warning about variables which are declared but never used.
139 This can be avoided by adding the \fInoref\fR keyword in front of the
140 variable declaration. Additionally a complete section of unreferenced
141 variables can be opened using \fI#pragma noref 1\fR, and closed via
142 \fI#pragma noref 0\fR.
144 .B -Wused-uninitialized
145 Generate a warning if it is possible that a variable can be used
146 without prior initialization. Note that this warning is not
147 necessarily reliable if the initialization happens only under certain
148 conditions. The other way is \fInot\fR possible: that the warning is
149 \fInot\fR generated when uninitialized use \fIis possible\fR.
151 .B -Wunknown-control-sequence
152 Generate an error when an unrecognized control sequence in a string is
153 used. Meaning: when there's a character after a backslash in a string
154 which has no known meaning.
157 Warn when using special extensions which are not part of the selected
160 .B -Wfield-redeclared
161 Generally QC compilers ignore redeclaration of fields. Here you can
162 optionally enable a warning.
164 .B -Wmissing-return-values
165 Functions which aren't of type \fIvoid\fR will warn if it possible to
166 reach the end without returning an actual value.
168 .B -Wtoo-few-parameters
169 Warn about a function call with fewer parameters than the function
173 Warn when a locally declared variable shadows variable.
176 Warn when the initialization of a local variable turns the variable
177 into a constant. This is default behaviour unless
178 \fI-finitialized-nonconstants\fR is used.
181 There are only 2 known global variables of type void: end_sys_globals
182 and end_sys_fields. Any other void-variable will warn.
184 .B -Wimplicit-function-pointer
185 A global function which is not declared with the \fIvar\fR keyword is
186 expected to have an implementing body, or be a builtin. If neither is
187 the case, it implicitly becomes a function pointer, and a warning is
190 .B -Wvariadic-function
191 Currently there's no way for an in QC implemented function to access
192 variadic parameters. If a function with variadic parameters has an
193 implementing body, a warning will be generated.
196 Generate warnings about \fI$frame\fR commands, for instance about
197 duplicate frame definitions.
199 .B -Weffectless-statement
200 Warn about statements which have no effect. Any expression which does
201 not call a function or assigns a variable.
204 The \fIend_sys_fields\fR variable is supposed to be a global variable
205 of type \fIvoid\fR. It is also recognized as a \fIfield\fR but this
206 will generate a warning.
208 .B -Wassign-function-types
209 Warn when assigning to a function pointer with an unmatching
210 signature. This usually happens in cases like assigning the null
211 function to an entity's .think function pointer.
214 Enable warnings coming from the preprocessor. Like duplicate macro
215 declarations. This warning triggers when there's a problem with the
216 way the preprocessor has been used, it will \fBnot\fR affect warnings
217 generated with the '#warning' directive. See -Wcpp.
220 Show warnings created using the preprocessor's '#warning' directive.
223 Warn if there's a preprocessor \fI#if\fR spanning across several
226 .B -Wdouble-declaration
227 Warn about multiple declarations of globals. This seems pretty common
228 in QC code so you probably do not want this unless you want to clean
232 The combination of \fIconst\fR and \fIvar\fR is not illegal, however
233 different compilers may handle them differently. We were told, the
234 intention is to create a function-pointer which is not assignable.
235 This is exactly how we interpret it. However for this interpretation
236 the \fIvar\fR keyword is considered superfluous (and philosophically
237 wrong), so it is possible to generate a warning about this.
239 .B -Wmultibyte-character
240 Warn about multibyte character constants, they do not work right now.
242 .B -Wternary-precedence
243 Warn if a ternary expression which contains a comma operator is used
244 without enclosing parenthesis, since this is most likely not what you
245 actually want. We recommend the \fI-fcorrect-ternary\fR option.
248 Warn when encountering an unrecognized \fI#pragma\fR line.
250 .B -Wunreachable-code
251 Warn about unreachable code. That is: code after a return statement,
252 or code after a call to a function marked as 'noreturn'.
255 Enable some warnings added in order to help debugging in the compiler.
257 .B -Wunknown-attribute
258 Warn on an unknown attribute. The warning will inlclude only the first
259 token inside the enclosing attribute-brackets. This may change when
260 the actual attribute syntax is better defined.
263 Warn when using reserved names such as 'nil'.
266 .B -fdarkplaces-string-table-bug
267 Add some additional characters to the string table in order to
268 compensate for a wrong boundcheck in some specific version of the
271 .B -fadjust-vector-fields
272 When assigning to field pointers of type \fI.vector\fR the common
273 behaviour in compilers like \fIfteqcc\fR is to only assign the
274 x-component of the pointer. This means that you can use the vector as
275 such, but you cannot use its y and z components directly. This flag
276 fixes this behaviour. Before using it make sure your code does not
277 depend on the buggy behaviour.
280 Enable a partially fteqcc-compatible preprocessor. It supports all the
281 features used in the Xonotic codebase. If you need more, write a
285 Enable some predefined macros. This only works in combination with
286 \'-fftepp' and is currently not included by '-std=fteqcc'. The
287 following macros will be added:
298 Note that fteqcc also defines __FUNC__, __TIME__, __DATE__ and
299 __NULL__, which are not yet implemented.
302 Allow switch cases to use non constant variables.
305 Perform early out in logical AND and OR expressions. The final result
306 will be either a 0 or a 1, see the next flag for more possibilities.
309 In many languages, logical expressions perform early out in a special
310 way: If the left operand of an AND yeilds true, or the one of an OR
311 yields false, the complete expression evaluates to the right side.
312 Thus \fItrue && 5\fI evaluates to 5 rather than 1.
314 .B -ftranslatable-strings
315 Enable the underscore intrinsic: Using \fI_("A string constant")\fR
316 will cause the string immediate to get a name with a "dotranslate_"
317 prefix. The darkplaces engine recognizes these and translates them in
318 a way similar to how gettext works.
320 .B -finitialized-nonconstants
321 Don't implicitly convert initialized variables to constants. With this
322 flag, the \fIconst\fR keyword is required to make a constant.
324 .B -fassign-function-types
325 If this flag is not set, (and it is set by default in the qcc and
326 fteqcc standards), assigning function pointers of mismatching
327 signatures will result in an error rather than a warning.
330 Produce a linenumber file along with the output .dat file.
333 Use C's operator precedence for ternary expressions. Unless your code
334 depends on fteqcc-compatible behaviour, you'll want to use thi
337 .B -fsingle-vector-defs
338 Normally vectors generate 4 defs, once for the vector, and once for
339 its components with _x, _y, _z suffixes. This option
340 prevents components from being listed.
343 Most QC compilers translate if(a_vector) directly as an IF on the
344 vector, which means only the x-component is checked. This causes
345 vectors to be cast to actual booleans via a NOT_V and, if necessary, a
349 if (a_vector) // becomes
352 a = a_vector && a_float // becomes
353 a = !!a_vector && a_float
357 .B -ftrue-empty-strings
358 An empty string is considered to be true everywhere. The NOT_S
359 instruction usually considers an empty string to be false, this option
360 effectively causes the unary not in strings to use NOT_F instead.
362 .B -ffalse-empty-strings
363 An empty string is considered to be false everywhere. This means loops
364 and if statements which depend on a string will perform a NOT_S
365 instruction on the string before using it.
368 Enable utf8 characters. This allows utf-8 encoded character constants,
369 and escape sequence codepoints in the valid utf-8 range. Effectively
370 enabling escape sequences like '\\{x2211}'.
373 When a warning is treated as an error, and this option is set (which
374 it is by default), it is like any other error and will cause
375 compilation to stop. When disabling this flag by using
376 \-fno-bail-on-werror, compilation will continue until the end, but no
377 output is generated. Instead the first such error message's context is
381 Allow loops to be labeled, and allow 'break' and 'continue' to take an
382 optional label to decide which loop to actually jump out of or
387 for :outer (i = 0; i < n; ++i) {
398 Adds a global named 'nil' which is of no type and can be assigned to
399 anything. No typechecking will be performed on assignments. Assigning
400 to it is forbidden, using it in any other kind of expression is also
404 Various effects, usually to weaken some conditions.
406 .IP "with -funtyped-nil"
407 Allow local variables named 'nil'. (This will not allow declaring a
408 global of that name.)
412 Some general peephole optimizations. For instance the code `a = b + c`
413 typically generates 2 instructions, an ADD and a STORE. This
414 optimization removes the STORE and lets the ADD write directly into A.
417 Tail recursive function calls will be turned into loops to avoid the
418 overhead of the CALL and RETURN instructions.
421 Make all functions which use neither local arrays nor have locals
422 which are seen as possibly uninitialized use the same local section.
423 This should be pretty safe compared to other compilers which do not
424 check for uninitialized values properly. The problem is that there's
425 QC code out there which really doesn't initialize some values. This is
426 fine as long as this kind of optimization isn't used, but also, only
427 as long as the functions cannot be called in a recursive manner. Since
428 it's hard to know whether or not an array is actually fully
429 initialized, especially when initializing it via a loop, we assume
430 functions with arrays to be too dangerous for this optimization.
433 This promotes locally declared variables to "temps". Meaning when a
434 temporary result of an operation has to be stored somewhere, a local
435 variable which is not 'alive' at that point can be used to keep the
436 result. This can reduce the size of the global section.
437 This will not have declared variables overlap, even if it was
441 Causes temporary values which do not need to be backed up on a CALL to
442 not be stored in the function's locals-area. With this, a CALL to a
443 function may need to back up fewer values and thus execute faster.
445 .B -Ostrip-constant-names
446 Don't generate defs for immediate values or even declared constants.
447 Meaning variables which are implicitly constant or qualified as such
448 using the 'const' keyword.
451 Aggressively reuse strings in the string section. When a string should
452 be added which is the trailing substring of an already existing
453 string, the existing string's tail will be returned instead of the new
456 For example the following code will only generate 1 string:
460 print("Hell you!\\n");
461 print("you!\\n"); // trailing substring of "Hello you!\\n"
464 There's however one limitation. Strings are still processed in order,
465 so if the above print statements were reversed, this optimization
469 By default, all parameters of a CALL are copied into the
470 parameter-globals right before the CALL instructions. This is the
471 easiest and safest way to translate calls, but also adds a lot of
472 unnecessary copying and unnecessary temporary values. This
473 optimization makes operations which are used as a parameter evaluate
474 directly into the parameter-global if that is possible, which is when
475 there's no other CALL instruction in between.
478 Usually an empty RETURN instruction is added to the end of a void
479 typed function. However, additionally after every function a DONE
480 instruction is added for several reasons. (For example the qcvm's
481 disassemble switch uses it to know when the function ends.). This
482 optimization replaces that last RETURN with DONE rather than adding
483 the DONE additionally.
485 The configuration file is similar to regular .ini files. Comments
486 start with hashtags or semicolons, sections are written in square
487 brackets and in each section there can be arbitrary many key-value
490 There are 3 sections currently:
491 .IR flags ", " warnings ", and " optimizations .
492 They contain a list of boolean values of the form `VARNAME = true` or
493 `VARNAME = false`. The variable names are the same as for the
494 corresponding -W, -f or -O flag written with only capital letters and
495 dashes replaced by underscores.
500 # a GMQCC configuration file
503 ADJUST_VECTOR_FIELDS = false
507 UNUSED_VARIABLE = false
508 USED_UNINITIALIZED = true
512 TAIL_RECURSION = true
516 Currently the '-fftepp-predefs' flag is not included by '-std=fteqcc',
517 partially because it is not entirely conformant to fteqcc.
520 Please report bugs on <http://github.com/graphitemaster/gmqcc/issues>,
521 or see <http://graphitemaster.github.com/gmqcc> on how to contact us.
525 A documented example for a gmqcc.ini file.
529 See <http://graphitemaster.github.com/gmqcc>.
projects / xonotic / gmqcc.git / blob