7 .Nd A Quake C compiler built from the NIH realm of sarcastic wit
13 Traditionally, a QC compiler reads the file
15 which in its first line contains the output filename, and the rest is a
16 list of QC source files that are to be compiled in order.
18 optionally takes options to specify the output and
19 input files on the commandline, and also accepts assembly files.
22 mostly tries to mimic gcc's commandline handling, though
23 there are also traditional long-options available.
26 Show a usage message and exit.
27 .It Fl o , Fl -output= Ns Ar filename
28 Specify the output filename. Defaults to progs.dat. This will overwrite
29 the output file listed in a
31 file in case such a file is used.
32 .Bl -tag -width indent
34 Specify the optimization level
36 Highest optimization level
38 Default optimization level
40 Minimal optimization level
42 Disable optimization entirely
45 .It Fl O Ns Ar name , Fl Ono- Ns Ar name
46 Enable or disable a specific optimization. Note that these options
47 must be used after setting the optimization level, otherwise they'll
50 List all possible optimizations and the optimization level they're
53 Be less verbose. In particular removes the messages about which files
54 are being processed, and which compilation mode is being used, and
55 some others. Warnings and errors will of course still be displayed.
56 .It Fl D Ns Ar macroname , Fl D Ns Ar macroname Ns = Ns Ar value
57 Predefine a macro, optionally with a optional value.
59 Run only the preprocessor as if
61 was used and print the preprocessed code to stdout.
62 .It Fl W Ns Ar warning , Fl Wno- Ns Ar warning
63 Enable or disable a warning.
65 Enable almost all warnings. Overrides preceding
69 The following warnings will
72 .Bl -tag -width indent -offset indent
73 .It Fl W Ns Cm uninitialized-global
75 .It Fl W Ns Cm error , Fl Wno- Ns Cm error
76 Controls whether or not all warnings should be treated as errors.
77 .It Fl Werror- Ns Ar warning , Fl Wno-error- Ns Ar warning
78 Controls whether a specific warning should be an error.
80 List all possible warn flags.
81 .It Fl f Ns Ar flag , Fl fno- Ns Ar flag
82 Enable or disable a specific compile flag. See the list of flags
85 List all possible compile flags.
87 Disables colored output
88 .It Fl config= Ns Ar file
89 Use an ini file to read all the
95 Turn on some compiler debugging mechanisms.
97 Turn on compiler mem-check. (Shows allocations and checks for leaks.)
98 .It Fl -memdumpcols Ns Ar columns
99 Changes the number of columns to use for the debug memory dump, defaults to 16.
101 section about the file format.
102 .It Fl redirout= Ns Ar file
103 Redirects standard output to a
105 .It Fl redirerr= Ns Ar file
106 Redirects standard error to a
108 .It Fl std= Ns Ar standard
109 Use the specified standard for parsing QC code. The following standards
111 .Ar gmqcc , Ar qcc , Ar fteqcc
112 Selecting a standard also implies some
114 options and behaves as if
115 those options have been written right after the
118 if you changed them before the
120 option, you're now overwriting them.
122 .Fl std= Ns Cm gmqcc No includes:
123 .Bl -tag -width indent -compact -offset Ds
124 .It Fl f Ns Cm adjust-vector-fields
125 .It Fl f Ns Cm correct-logic
126 .It Fl f Ns Cm true-empty-strings
127 .It Fl f Ns Cm loop-labels
128 .It Fl f Ns Cm initialized-nonconstants
129 .It Fl f Ns Cm translatable-strings
130 .It Fl fno- Ns Cm false-empty-strings
131 .It Fl W Ns Cm invalid-parameter-count
132 .It Fl W Ns Cm missing-returnvalues
133 .It Fl f Ns Cm correct-ternary Li (cannot be turned off)
136 .Fl std= Ns Cm qcc No includes:
137 .Bl -tag -width indent -compact -offset Ds
138 .It Fl f Ns Cm assign-function-types
139 .It Fl fIno- Ns Cm adjust-vector-fields
142 .Fl std= Ns Cm fteqcc No includes:
143 .Bl -tag -width indent -compact -offset Ds
145 .It Fl f Ns Cm translatable-strings
146 .It Fl f Ns Cm assign-function-types
147 .It Fl W Ns Cm ternary-precedence
148 .It Fl fno- Ns Cm adjust-vector-fields
149 .It Fl fno- Ns Cm correct-ternary
152 Adds compiler information to the generated binary file. Currently
153 this includes the following globals:
154 .Bl -tag -width indent -compact
155 .It Li reserved:version
156 String containing the compiler version as printed by the \-\-version
159 .It Fl -correct , Fl -no-correct
160 When enabled, errors about undefined values try to suggest an existing
161 value via spell checking.
163 DEBUG OPTION. Print the code's intermediate representation before the
164 optimization and finalization passes to stdout before generating the
167 DEBUG OPTION. Print the code's intermediate representation after the
168 optimization and finalization passes to stdout before generating the
169 binary. The instructions will be enumerated, and values will contain a
171 .It Fl force-crc= Ns Ar CRC
172 Force the produced progs file to use the specified CRC.
173 .It Fl state-fps= Ns Ar NUM
174 Activate \-femulate-state and set the emulated FPS to
179 .It Fl W Ns Cm unused-variable
180 Generate a warning about variables which are declared but never used.
181 This can be avoided by adding the
183 keyword in front of the
184 variable declaration. Additionally a complete section of unreferenced
185 variables can be opened using
188 .Ql #pragma noref 0 Ns .
189 .It Fl W Ns Cm used-uninitialized
190 Generate a warning if it is possible that a variable can be used
191 without prior initialization. Note that this warning is not
192 necessarily reliable if the initialization happens only under certain
193 conditions. The other way is
195 possible: that the warning is
197 generated when uninitialized use
200 .It Fl W Ns Cm unknown-control-sequence
201 Generate an error when an unrecognized control sequence in a string is
202 used. Meaning: when there's a character after a backslash in a string
203 which has no known meaning.
204 .It Fl W Ns Cm extensions
205 Warn when using special extensions which are not part of the selected
207 .It Fl W Ns Cm field-redeclared
208 Generally QC compilers ignore redeclaration of fields. Here you can
209 optionally enable a warning.
210 .It Fl W Ns Cm missing-return-values
211 Functions which aren't of type
213 will warn if it possible to
214 reach the end without returning an actual value.
215 .It Fl W Ns Cm invalid-parameter-count
216 Warn about a function call with an invalid number of parameters.
217 .It Fl W Ns Cm local-shadows
218 Warn when a locally declared variable shadows variable.
219 .It Fl W Ns Cm local-constants
220 Warn when the initialization of a local variable turns the variable
221 into a constant. This is default behaviour unless
222 .Fl f Ns Cm initialized-nonconstants
224 .It Fl W Ns Cm void-variables
225 There are only 2 known global variables of type void:
228 .Ql end_sys_fields Ns .
229 Any other void-variable will warn.
230 .It Fl W Ns Cm implicit-function-pointer
231 A global function which is not declared with the
234 expected to have an implementing body, or be a builtin. If neither is
235 the case, it implicitly becomes a function pointer, and a warning is
237 .It Fl W Ns Cm variadic-function
238 Currently there's no way for an in QC implemented function to access
239 variadic parameters. If a function with variadic parameters has an
240 implementing body, a warning will be generated.
241 .It Fl W Ns Cm frame-macros
242 Generate warnings about
244 commands, for instance about
245 duplicate frame definitions.
246 .It Fl W Ns Cm effectless-statement
247 Warn about statements which have no effect. Any expression which does
248 not call a function or assigns a variable.
249 .It Fl W Ns Cm end-sys-fields
252 variable is supposed to be a global variable
255 It is also recognized as a \fIfield\fR but this
256 will generate a warning.
257 .It Fl W Ns Cm assign-function-types
258 Warn when assigning to a function pointer with an unmatching
259 signature. This usually happens in cases like assigning the null
260 function to an entity's .think function pointer.
262 Show warnings created using the preprocessor's '#warning' directive.
263 .It Fl W Ns Cm multifile-if
264 Warn if there's a preprocessor \fI#if\fR spanning across several
266 .It Fl W Ns Cm double-declaration
267 Warn about multiple declarations of globals. This seems pretty common
268 in QC code so you probably do not want this unless you want to clean
270 .It Fl W Ns Cm const-var
271 The combination of \fIconst\fR and \fIvar\fR is not illegal, however
272 different compilers may handle them differently. We were told, the
273 intention is to create a function-pointer which is not assignable.
274 This is exactly how we interpret it. However for this interpretation
277 keyword is considered superfluous (and philosophically
278 wrong), so it is possible to generate a warning about this.
279 .It Fl W Ns Cm multibyte-character
280 Warn about multibyte character constants, they do not work right now.
281 .It Fl W Ns Cm ternary-precedence
282 Warn if a ternary expression which contains a comma operator is used
283 without enclosing parenthesis, since this is most likely not what you
284 actually want. We recommend the
285 .Fl f Ns Cm correct-ternary
287 .It Fl W Ns Cm unknown-pragmas
288 Warn when encountering an unrecognized
291 .It Fl W Ns Cm unreachable-code
292 Warn about unreachable code. That is: code after a return statement,
293 or code after a call to a function marked as 'noreturn'.
295 Enable some warnings added in order to help debugging in the compiler.
297 .It Fl W Ns Cm unknown-attribute
298 Warn on an unknown attribute. The warning will inlclude only the first
299 token inside the enclosing attribute-brackets. This may change when
300 the actual attribute syntax is better defined.
301 .It Fl W Ns Cm reserved-names
302 Warn when using reserved names such as
304 .It Fl W Ns Cm uninitialized-constant
305 Warn about global constants (using the
309 .It Fl W Ns Cm uninitialized-global
310 Warn about global variables with no initializing value. This is off by
311 default, and is added mostly to help find null-values which are
312 supposed to be replaced by the untyped 'nil' constant.
313 .It Fl W Ns Cm different-qualifiers
314 Warn when a variables is redeclared with a different qualifier. For
315 example when redeclaring a variable as \'var\' which was previously
317 .It Fl W Ns Cm different-attributes
318 Similar to the above but for attributes like
319 .Ql [[noreturn]] Ns .
320 .It Fl W Ns Cm deprecated
321 Warn when a function is marked with the attribute
322 "[[deprecated]]". This flag enables a warning on calls to functions
324 .It Fl W Ns Cm parenthesis
325 Warn about possible mistakes caused by missing or wrong parenthesis,
326 like an assignment in an 'if' condition when there's no additional set
327 of parens around the assignment.
328 .It Fl W Ns Cm unsafe-types
329 When passing variadic parameters via
331 it can happen that incompatible types are passed to functions. This
332 enables several warnings when static typechecking cannot guarantee
334 .It Fl W Ns Cm breakdef
335 When compiling original id1 QC there is a definition for `break`
336 which conflicts with the 'break' keyword in GMQCC. Enabling this
337 will print a warning when the definition occurs. The definition is
338 ignored for both cases.
339 .It Fl W Ns Cm const-overwrite
340 When compiling original QuakeWorld QC there are instances where
341 code overwrites constants. This is considered an error, however
342 for QuakeWorld to compile it needs to be treated as a warning
343 instead, as such this warning only works when \-std=qcc.
344 .It Fl W Ns Cm directive-inmacro
345 Warn about the use of preprocessor directives inside macros.
346 .It Fl W Ns Cm builtins
347 When using a function that is not explicitly defined, the compiler
348 will search its intrinsics table for something that matches that
349 function name by appending "__builtin_" to it. This behaviour may
350 be unexpected, so enabling this will produce a diagnostic when
351 such a function is resolved to a builtin.
352 .It Fl W Ns Cm inexact-compares
353 When comparing an inexact value such as `1.0/3.0' the result is
354 pathologically wrong. Enabling this will trigger a compiler warning
359 .It Fl f Ns Cm darkplaces-string-table-bug
360 Add some additional characters to the string table in order to
361 compensate for a wrong boundcheck in some specific version of the
363 .It Fl f Ns Cm adjust-vector-fields
364 When assigning to field pointers of type \fI.vector\fR the common
365 behaviour in compilers like \fIfteqcc\fR is to only assign the
366 x-component of the pointer. This means that you can use the vector as
367 such, but you cannot use its y and z components directly. This flag
368 fixes this behaviour. Before using it make sure your code does not
369 depend on the buggy behaviour.
371 Enable a partially fteqcc-compatible preprocessor. It supports all the
372 features used in the Xonotic codebase. If you need more, write a
374 .It Fl f Ns Cm ftepp-predefs
375 Enable some predefined macros. This only works in combination with
376 \'\-fftepp' and is currently not included by '\-std=fteqcc'. The
377 following macros will be added:
378 .Bd -literal -offset indent
392 is not actually a preprocessor macro, but is recognized by the parser
393 even with the preprocessor disabled.
395 Note that fteqcc also defines
397 which becomes the first global. Assigning it to a vector does not
398 yield the same result as in gmqcc where
403 .Fl f Ns Cm untyped-nil
404 ), which will cause the vector to be zero in all components. With fteqcc
405 only the first component will be 0, while the other two will become
406 the first to of the global return value. This behavior is odd and
407 relying on it should be discouraged, and thus is not supported by
409 .It Fl f Ns Cm ftepp-mathdefs
410 Enable math constant definitions. This only works in combination
411 with \'\-fftepp' and is currently not included by '\-std=fteqcc'.
412 The following macros will be added:
413 .Bd -literal -offset indent
429 .It Fl f Ns Cm relaxed-switch
430 Allow switch cases to use non constant variables.
431 .It Fl f Ns Cm short-logic
432 Perform early out in logical AND and OR expressions. The final result
433 will be either a 0 or a 1, see the next flag for more possibilities.
434 .It Fl f Ns Cm perl-logic
435 In many languages, logical expressions perform early out in a special
436 way: If the left operand of an AND yeilds true, or the one of an OR
437 yields false, the complete expression evaluates to the right side.
440 evaluates to 5 rather than 1.
441 .It Fl f Ns Cm translatable-strings
442 Enable the underscore intrinsic: Using
443 .Ql _("A string constant")
444 will cause the string immediate to get a name with a "dotranslate_"
445 prefix. The darkplaces engine recognizes these and translates them in
446 a way similar to how gettext works.
447 .It Fl f Ns Cm initialized-nonconstants
448 Don't implicitly convert initialized variables to constants. With this
449 flag, the \fIconst\fR keyword is required to make a constant.
450 .It Fl f Ns Cm assign-function-types
451 If this flag is not set, (and it is set by default in the qcc and
452 fteqcc standards), assigning function pointers of mismatching
453 signatures will result in an error rather than a warning.
455 Produce a linenumber file along with the output .dat file.
456 .It Fl f Ns Cm correct-ternary
457 Use C's operator precedence for ternary expressions. Unless your code
458 depends on fteqcc-compatible behaviour, you'll want to use thi
460 .It Fl f Ns Cm single-vector-defs
461 Normally vectors generate 4 defs, once for the vector, and once for
462 its components with _x, _y, _z suffixes. This option
463 prevents components from being listed.
464 .It Fl f Ns Cm correct-logic
465 Most QC compilers translate
467 directly as an IF on the
468 vector, which means only the x-component is checked. This option causes
469 vectors to be cast to actual booleans via a NOT_V and, if necessary, a
471 .Bd -literal -offset indent
472 if (a_vector) // becomes
475 a = a_vector && a_float // becomes
476 a = !!a_vector && a_float
478 .It Fl f Ns Cm true-empty-strings
479 An empty string is considered to be true everywhere. The NOT_S
480 instruction usually considers an empty string to be false, this option
481 effectively causes the unary not in strings to use NOT_F instead.
482 .It Fl f Ns Cm false-empty-strings
483 An empty string is considered to be false everywhere. This means loops
484 and if statements which depend on a string will perform a NOT_S
485 instruction on the string before using it.
487 Enable utf8 characters. This allows utf-8 encoded character constants,
488 and escape sequence codepoints in the valid utf-8 range. Effectively
489 enabling escape sequences like '\\{x2211}'.
490 .It Fl f Ns Cm bail-on-werror
491 When a warning is treated as an error, and this option is set (which
492 it is by default), it is like any other error and will cause
493 compilation to stop. When disabling this flag by using
494 \-fno-bail-on-werror, compilation will continue until the end, but no
495 output is generated. Instead the first such error message's context is
497 .It Fl f Ns Cm loop-labels
498 Allow loops to be labeled, and allow 'break' and 'continue' to take an
499 optional label to decide which loop to actually jump out of or
501 .Bd -literal -offset indent
502 for :outer (i = 0; i < n; ++i) {
510 .It Fl f Ns Cm untyped-nil
511 Adds a global named 'nil' which is of no type and can be assigned to
512 anything. No typechecking will be performed on assignments. Assigning
513 to it is forbidden, using it in any other kind of expression is also
516 Note that this is different from fteqcc's __NULL__: In fteqcc,
517 __NULL__ maps to the integer written as '0i'. It's can be assigned to
518 function pointers and integers, but it'll error about invalid
519 instructions when assigning it to floats without enabling the FTE
520 instruction set. There's also a bug which allows it to be assigned to
521 vectors, for which the source will be the global at offset 0, meaning
522 the vector's y and z components will contain the OFS_RETURN x and y
525 In that gmqcc the nil global is an actual global filled with zeroes,
526 and can be assigned to anything including fields, vectors or function
527 pointers, and they end up becoming zeroed.
528 .It Fl f Ns Cm permissive
529 Various effects, usually to weaken some conditions.
530 .Bl -tag -width indent -offset indent
531 .It with Fl f Ns Cm untyped-nil
532 Allow local variables named
534 (This will not allow declaring a global of that name.)
536 .It Fl f Ns Cm variadic-args
537 Allow variadic parameters to be accessed by QC code. This can be
538 achieved via the '...' function, which takes a parameter index and a
542 .Bd -literal -offset indent
543 void vafunc(string...count) {
545 for (i = 0; i < count; ++i)
546 print(...(i, string), "\\n");
549 .It Fl f Ns Cm legacy-vector-maths
550 Most Quake VMs, including the one from FTEQW or up till recently
551 Darkplaces, do not cope well with vector instructions with overlapping
552 input and output. This option will avoid producing such code.
553 .It Fl f Ns Cm expressions-for-builtins
554 Usually builtin-numbers are just immediate constants. With this flag
555 expressions can be used, as long as they are compile-time constant.
558 .Bd -literal -offset indent
559 void printA() = #1; // the usual way
560 void printB() = #2-1; // with a constant expression
562 .It Fl f Ns Cm return-assignments
563 Enabiling this option will allow assigning values or expressions to the
564 return keyword as if it were a local variable of the same type as the
565 function's signature's return type.
568 .Bd -literal -offset indent
569 float bar() { return 1024; }
572 return; // returns value of bar
575 .It Fl f Ns Cm unsafe-varargs
576 When passing on varargs to a different functions, this turns some
577 static error cases into warnings. Like when the caller's varargs are
578 restricted to a different type than the callee's parameter. Or a list
579 of unrestricted varargs is passed into restricted varargs.
580 .It Fl f Ns Cm typeless-stores
581 Always use STORE_F, LOAD_F, STOREP_F when accessing scalar variables.
582 This is somewhat incorrect assembly instruction use, but in all engines
583 they do exactly the same. This makes disassembly output harder to read,
584 breaks decompilers, but causes the output file to be better compressible.
585 .It Fl f Ns Cm sort-operands
586 In commutative instructions, always put the lower-numbered operand first.
587 This shaves off 1 byte of entropy from all these instructions, reducing
588 compressed size of the output file.
589 .It Fl f Ns Cm emulate-state
590 Emulate OP_STATE operations in code rather than using the instruction.
591 The desired fps can be set via -state-fps=NUM, defaults to 10.
592 Specifying \-state-fps implicitly sets this flag. Defaults to off in all
594 .It Fl f Ns Cm arithmetic-exceptions
595 Turn on arithmetic exception tests in the compiler. In constant expressions
596 which trigger exceptions like division by zero, overflow, underflow, etc,
597 the following flag will produce diagnostics for what triggered that
602 .It Fl O Ns Cm peephole
603 Some general peephole optimizations. For instance the code `a = b + c`
604 typically generates 2 instructions, an ADD and a STORE. This
605 optimization removes the STORE and lets the ADD write directly into A.
606 .It Fl O Ns Cm tail-recursion
607 Tail recursive function calls will be turned into loops to avoid the
608 overhead of the CALL and RETURN instructions.
609 .It Fl O Ns Cm overlap-locals
610 Make all functions which use neither local arrays nor have locals
611 which are seen as possibly uninitialized use the same local section.
612 This should be pretty safe compared to other compilers which do not
613 check for uninitialized values properly. The problem is that there's
614 QC code out there which really doesn't initialize some values. This is
615 fine as long as this kind of optimization isn't used, but also, only
616 as long as the functions cannot be called in a recursive manner. Since
617 it's hard to know whether or not an array is actually fully
618 initialized, especially when initializing it via a loop, we assume
619 functions with arrays to be too dangerous for this optimization.
620 .It Fl O Ns Cm local-temps
621 This promotes locally declared variables to "temps". Meaning when a
622 temporary result of an operation has to be stored somewhere, a local
623 variable which is not 'alive' at that point can be used to keep the
624 result. This can reduce the size of the global section.
625 This will not have declared variables overlap, even if it was
627 .It Fl O Ns Cm global-temps
628 Causes temporary values which do not need to be backed up on a CALL to
629 not be stored in the function's locals-area. With this, a CALL to a
630 function may need to back up fewer values and thus execute faster.
631 .It Fl O Ns Cm strip-constant-names
632 Don't generate defs for immediate values or even declared constants.
633 Meaning variables which are implicitly constant or qualified as such
634 using the 'const' keyword.
635 .It Fl O Ns Cm overlap-strings
636 Aggressively reuse strings in the string section. When a string should
637 be added which is the trailing substring of an already existing
638 string, the existing string's tail will be returned instead of the new
641 For example the following code will only generate 1 string:
642 .Bd -literal -offset indent
643 print("Hello you!\\n");
644 print("you!\\n"); // trailing substring of "Hello you!\\n"
647 There's however one limitation. Strings are still processed in order,
648 so if the above print statements were reversed, this optimization
650 .It Fl O Ns Cm call-stores
651 By default, all parameters of a CALL are copied into the
652 parameter-globals right before the CALL instructions. This is the
653 easiest and safest way to translate calls, but also adds a lot of
654 unnecessary copying and unnecessary temporary values. This
655 optimization makes operations which are used as a parameter evaluate
656 directly into the parameter-global if that is possible, which is when
657 there's no other CALL instruction in between.
658 .It Fl O Ns Cm void-return
659 Usually an empty RETURN instruction is added to the end of a void
660 typed function. However, additionally after every function a DONE
661 instruction is added for several reasons. (For example the qcvm's
662 disassemble switch uses it to know when the function ends.). This
663 optimization replaces that last RETURN with DONE rather than adding
664 the DONE additionally.
665 .It Fl O Ns Cm vector-components
666 Because traditional QC code doesn't allow you to access individual
667 vector components of a computed vector without storing it in a local
668 first, sometimes people multiply it by a constant like
671 in this case, the y component of a vector. This optimization will turn
672 such a multiplication into a direct component access. If the factor is
673 anything other than 1, a float-multiplication will be added, which is
674 still faster than a vector multiplication.
675 .It Fl O Ns Cm const-fold-dce
676 For constant expressions that result in dead code (such as a branch whos
677 condition can be evaluated at compile-time), this will eliminate the branch
678 and else body (if present) to produce more optimal code.
681 The configuration file is similar to regular .ini files. Comments
682 start with hashtags or semicolons, sections are written in square
683 brackets and in each section there can be arbitrary many key-value
686 There are 3 sections currently:
689 .Ql optimizations Ns .
690 They contain a list of boolean values of the form
693 .Ql VARNAME = false Ns .
694 The variable names are the same as for the
699 flag written with only capital letters and
700 dashes replaced by underscores.
703 .Bd -literal -offset indent
704 # a GMQCC configuration file
707 ADJUST_VECTOR_FIELDS = false
711 UNUSED_VARIABLE = false
712 USED_UNINITIALIZED = true
716 TAIL_RECURSION = true
720 .It gmqcc.ini.example
721 A documented example for a gmqcc.ini file.
726 See <http://graphitemaster.github.com/gmqcc>.
728 Currently the '\-fftepp-predefs' flag is not included by '\-std=fteqcc',
729 partially because it is not entirely conformant to fteqcc.
731 Please report bugs on <http://github.com/graphitemaster/gmqcc/issues>,
732 or see <http://graphitemaster.github.com/gmqcc> on how to contact us.