-.\" Process with groff -man -Tascii file.3
-.TH GMQCC 1 2012-07-12 "" "gmqcc Manual"
-.SH NAME
-gmqcc \- A Quake C compiler built from the NIH realm of sarcastic wit
-.SH SYNOPSIS
-.B gmqcc
-[\fIOPTIONS\fR] [\fIfiles...\fR]
-.SH DESCRIPTION
-Traditionally, a QC compiler reads the file \fIprogs.src\fR which
-in its first line contains the output filename, and the rest is a
+.\"mdoc
+.Dd January 24, 2013
+.Dt GMQCC 1 PRM
+.Os
+.Sh NAME
+.Nm gmqcc
+.Nd A Quake C compiler built from the NIH realm of sarcastic wit
+.Sh SYNOPSIS
+.Nm gmqcc
+.Op Cm options
+.Op Ar files...
+.Sh DESCRIPTION
+Traditionally, a QC compiler reads the file
+.Pa progs.src
+which in its first line contains the output filename, and the rest is a
list of QC source files that are to be compiled in order.
-\fBgmqcc\fR optionally takes options to specify the output and
+.Nm gmqcc
+optionally takes options to specify the output and
input files on the commandline, and also accepts assembly files.
-.SH OPTIONS
-\fBgmqcc\fR mostly tries to mimick gcc's commandline handling, though
+.Sh OPTIONS
+.Nm gmqcc
+mostly tries to mimic gcc's commandline handling, though
there are also traditional long-options available.
-.TP
-.B "-h, --help"
+.Bl -tag -width Ds
+.It Fl h , Fl -help
Show a usage message and exit.
-.TP
-.B "-debug"
-Turn on some compiler debugging mechanisms.
-.TP
-.B "-memchk"
-Turn on compiler mem-check. (Shows allocations and checks for leaks.)
-.TP
-.BI "-o, --output=" filename
+.It Fl o , Fl -output= Ns Ar filename
Specify the output filename. Defaults to progs.dat. This will overwrite
-the output file listed in a \fIprogs.src\fR file in case such a file is used.
-.TP
-.BI "-O" number
+the output file listed in a
+.Pa progs.src
+file in case such a file is used.
+.Bl -tag -width indent
+.It Fl O Ns Ar number
Specify the optimization level
-.RS
-.IP 3
+.It Ar 3
Highest optimization level
-.IP 2
+.It Ar 2
Default optimization level
-.IP 1
+.It Ar 1
Minimal optimization level
-.IP 0
-Disable optimization entierly
-.RE
-.TP
-.BI "-O" name "\fR, " "" -Ono- name
+.It Ar 0
+Disable optimization entirely
+.El
+.Pp
+.It Fl O Ns Ar name , Fl Ono- Ns Ar name
Enable or disable a specific optimization. Note that these options
must be used after setting the optimization level, otherwise they'll
be overwritten.
-.TP
-.B -Ohelp
+.It Fl O Ns Cm help
List all possible optimizations and the optimization level they're
activated at.
-.TP
-.BI "-std=" standard
-Use the specified standard for parsing QC code. The following standards
-are available:
-.IR gmqcc , qcc , fteqcc
-.TP
-.BI -W warning "\fR, " "" -Wno- warning
+.It Fl q , Fl -quiet
+Be less verbose. In particular removes the messages about which files
+are being processed, and which compilation mode is being used, and
+some others. Warnings and errors will of course still be displayed.
+.It Fl D Ns Ar macroname , Fl D Ns Ar macroname Ns = Ns Ar value
+Predefine a macro, optionally with a optional value.
+.It Fl E
+Run only the preprocessor as if
+.Fl f Ns Cm ftepp
+was used and print the preprocessed code to stdout.
+.It Fl W Ns Ar warning , Fl Wno- Ns Ar warning
Enable or disable a warning.
-.TP
-.B -Wall
-Enable all warnings. Overrides preceding -W parameters.
-.TP
-.B -Whelp
+.It Fl W Ns Cm all
+Enable almost all warnings. Overrides preceding
+.Fl W
+parameters.
+.Pp
+The following warnings will
+.Em not
+be enabled:
+.Bl -tag -width indent -offset indent
+.It Fl W Ns Cm uninitialized-global
+.El
+.It Fl W Ns Cm error , Fl Wno- Ns Cm error
+Controls whether or not all warnings should be treated as errors.
+.It Fl Werror- Ns Ar warning , Fl Wno-error- Ns Ar warning
+Controls whether a specific warning should be an error.
+.It Fl W Ns Cm help
List all possible warn flags.
-.TP
-.BI -f flag "\fR, " "" -fno- flag
+.It Fl f Ns Ar flag , Fl fno- Ns Ar flag
Enable or disable a specific compile flag. See the list of flags
below.
-.TP
-.B -fhelp
+.It Fl f Ns Cm help
List all possible compile flags.
-.TP
-.B -nocolor
+.It Fl nocolor
Disables colored output
-.TP
-.BI "-redirout=" file
-Redirects standard output to a \fIfile\fR
-.TP
-.BI "-rediterr=" file
-Redirects standard error to a \fIfile\fR
-.SH Warnings
-.TP
-.B -Wunused-variable
+.It Fl config= Ns Ar file
+Use an ini file to read all the
+.Fl O , Fl W
+and
+.Fl f
+flag from. See the
+.It Fl "debug"
+Turn on some compiler debugging mechanisms.
+.It Fl memchk
+Turn on compiler mem-check. (Shows allocations and checks for leaks.)
+.It Fl -memdumpcols Ns Ar columns
+Changes the number of columns to use for the debug memory dump, defaults to 16.
+.Sx CONFIG
+section about the file format.
+.It Fl redirout= Ns Ar file
+Redirects standard output to a
+.Ar file
+.It Fl redirerr= Ns Ar file
+Redirects standard error to a
+.Ar file
+.It Fl std= Ns Ar standard
+Use the specified standard for parsing QC code. The following standards
+are available:
+.Ar gmqcc , Ar qcc , Ar fteqcc
+Selecting a standard also implies some
+.Fl f
+options and behaves as if
+those options have been written right after the
+.Fl std
+option, meaning
+if you changed them before the
+.Fl -std
+option, you're now overwriting them.
+.Pp
+.Fl std= Ns Cm gmqcc No includes:
+.Bl -tag -width indent -compact -offset Ds
+.It Fl f Ns Cm adjust-vector-fields
+.It Fl f Ns Cm correct-logic
+.It Fl f Ns Cm true-empty-strings
+.It Fl f Ns Cm loop-labels
+.It Fl f Ns Cm initialized-nonconstants
+.It Fl f Ns Cm translatable-strings
+.It Fl fno- Ns Cm false-empty-strings
+.It Fl W Ns Cm invalid-parameter-count
+.It Fl W Ns Cm missing-returnvalues
+.It Fl f Ns Cm correct-ternary Li (cannot be turned off)
+.El
+.Pp
+.Fl std= Ns Cm qcc No includes:
+.Bl -tag -width indent -compact -offset Ds
+.It Fl f Ns Cm assign-function-types
+.It Fl fIno- Ns Cm adjust-vector-fields
+.El
+.Pp
+.Fl std= Ns Cm fteqcc No includes:
+.Bl -tag -width indent -compact -offset Ds
+.It Fl f Ns Cm ftepp
+.It Fl f Ns Cm translatable-strings
+.It Fl f Ns Cm assign-function-types
+.It Fl W Ns Cm ternary-precedence
+.It Fl fno- Ns Cm adjust-vector-fields
+.It Fl fno- Ns Cm correct-ternary
+.El
+.It Fl -add-info
+Adds compiler information to the generated binary file. Currently
+this includes the following globals:
+.Bl -tag -width indent -compact
+.It Li reserved:version
+String containing the compiler version as printed by the --version
+parameter.
+.El
+.It Fl -correct , Fl -no-correct
+When enabled, errors about undefined values try to suggest an existing
+value via spell checking.
+.It Fl dump
+DEBUG OPTION. Print the code's intermediate representation before the
+optimization and finalization passes to stdout before generating the
+binary.
+.It Fl dumpfin
+DEBUG OPTION. Print the code's intermediate representation after the
+optimization and finalization passes to stdout before generating the
+binary. The instructions will be enumerated, and values will contain a
+list of liferanges.
+.El
+.Sh COMPILE WARNINGS
+.Bl -tag -width Ds
+.It Fl W Ns Cm unused-variable
Generate a warning about variables which are declared but never used.
-This can be avoided by adding the \fInoref\fR keyword in front of the
+This can be avoided by adding the
+.Ql noref
+keyword in front of the
variable declaration. Additionally a complete section of unreferenced
-variables can be opened using \fI#pragma noref 1\fR, and closed via
-\fI#pragma noref 0\fR.
-.TP
-.B -Wused-uninitialized
+variables can be opened using
+.Ql #pragma noref 1
+and closed via
+.Ql #pragma noref 0 Ns .
+.It Fl W Ns Cm used-uninitialized
Generate a warning if it is possible that a variable can be used
without prior initialization. Note that this warning is not
necessarily reliable if the initialization happens only under certain
-conditions. The other way is \fInot\fR possible: that the warning is
-\fInot\fR generated when uninitialized use \fIis possible\fR.
-.TP
-.B -Wunknown-control-sequence
+conditions. The other way is
+.Em not
+possible: that the warning is
+.Em not
+generated when uninitialized use
+.Em is
+possible.
+.It Fl W Ns Cm unknown-control-sequence
Generate an error when an unrecognized control sequence in a string is
used. Meaning: when there's a character after a backslash in a string
which has no known meaning.
-.TP
-.B -Wextensions
+.It Fl W Ns Cm extensions
Warn when using special extensions which are not part of the selected
standard.
-.TP
-.B -Wfield-redeclared
+.It Fl W Ns Cm field-redeclared
Generally QC compilers ignore redeclaration of fields. Here you can
optionally enable a warning.
-.TP
-.B -Wmissing-return-values
-Functions which aren't of type \fIvoid\fR will warn if it possible to
+.It Fl W Ns Cm missing-return-values
+Functions which aren't of type
+.Ft void
+will warn if it possible to
reach the end without returning an actual value.
-.TP
-.B -Wtoo-few-parameters
-Warn about a function call with fewer parameters than the function
-expects.
-.TP
-.B -Wlocal-shadows
+.It Fl W Ns Cm invalid-parameter-count
+Warn about a function call with an invalid number of parameters.
+.It Fl W Ns Cm local-shadows
Warn when a locally declared variable shadows variable.
-.TP
-.B -Wlocal-constants
+.It Fl W Ns Cm local-constants
Warn when the initialization of a local variable turns the variable
into a constant. This is default behaviour unless
-\fI-finitialized-nonconstants\fR is used.
-.TP
-.B -Wvoid-variables
-There are only 2 known global variables of type void: end_sys_globals
-and end_sys_fields. Any other void-variable will warn.
-.TP
-.B -Wimplicit-function-pointer
-A global function which is not declared with the \fIvar\fR keyword is
+.Fl f Ns Cm initialized-nonconstants
+is used.
+.It Fl W Ns Cm void-variables
+There are only 2 known global variables of type void:
+.Ql end_sys_globals
+and
+.Ql end_sys_fields Ns .
+Any other void-variable will warn.
+.It Fl W Ns Cm implicit-function-pointer
+A global function which is not declared with the
+.Ql var
+keyword is
expected to have an implementing body, or be a builtin. If neither is
the case, it implicitly becomes a function pointer, and a warning is
generated.
-.TP
-.B -Wvariadic-function
+.It Fl W Ns Cm variadic-function
Currently there's no way for an in QC implemented function to access
variadic parameters. If a function with variadic parameters has an
implementing body, a warning will be generated.
-.TP
-.B -Wframe-macros
-Generate warnings about \fI$frame\fR commands, for instance about
+.It Fl W Ns Cm frame-macros
+Generate warnings about
+.Ql $frame
+commands, for instance about
duplicate frame definitions.
-.TP
-.B -Weffectless-statement
+.It Fl W Ns Cm effectless-statement
Warn about statements which have no effect. Any expression which does
not call a function or assigns a variable.
-.TP
-.B -Wend-sys-fields
-The \fIend_sys_fields\fR variable is supposed to be a global variable
-of type \fIvoid\fR. It is also recognized as a \fIfield\fR but this
+.It Fl W Ns Cm end-sys-fields
+The
+.Ql end_sys_fields
+variable is supposed to be a global variable
+of type
+.Ft void Ns .
+It is also recognized as a \fIfield\fR but this
will generate a warning.
-.TP
-.B -Wassign-function-types
+.It Fl W Ns Cm assign-function-types
Warn when assigning to a function pointer with an unmatching
signature. This usually happens in cases like assigning the null
function to an entity's .think function pointer.
-.TP
-.B -Wpreprocessor
-Enable warnings coming from the preprocessor. Like duplicate macro
-declarations.
-.TP
-.B -Wmultifile-if
+.It Fl W Ns Cm cpp
+Show warnings created using the preprocessor's '#warning' directive.
+.It Fl W Ns Cm multifile-if
Warn if there's a preprocessor \fI#if\fR spanning across several
files.
-.TP
-.B -Wdouble-declaration
+.It Fl W Ns Cm double-declaration
Warn about multiple declarations of globals. This seems pretty common
in QC code so you probably do not want this unless you want to clean
up your code.
-.TP
-.B -Wconst-var
+.It Fl W Ns Cm const-var
The combination of \fIconst\fR and \fIvar\fR is not illegal, however
different compilers may handle them differently. We were told, the
intention is to create a function-pointer which is not assignable.
This is exactly how we interpret it. However for this interpretation
-the \fIvar\fR keyword is considered superfluous (and philosophically
+the
+.Ql var
+keyword is considered superfluous (and philosophically
wrong), so it is possible to generate a warning about this.
-.TP
-.B -Wmultibyte-character
+.It Fl W Ns Cm multibyte-character
Warn about multibyte character constants, they do not work right now.
-.TP
-.B -Wternary-precedence
+.It Fl W Ns Cm ternary-precedence
Warn if a ternary expression which contains a comma operator is used
without enclosing parenthesis, since this is most likely not what you
-actually want. We recommend the \fI-fcorrect-ternary\fR option.
-.TP
-.B -Wdebug
+actually want. We recommend the
+.Fl f Ns Cm correct-ternary
+option.
+.It Fl W Ns Cm unknown-pragmas
+Warn when encountering an unrecognized
+.Ql #pragma
+line.
+.It Fl W Ns Cm unreachable-code
+Warn about unreachable code. That is: code after a return statement,
+or code after a call to a function marked as 'noreturn'.
+.It Fl W Ns Cm debug
Enable some warnings added in order to help debugging in the compiler.
You won't need this.
-.SH Compile Flags
-.TP
-.B -foverlap-locals
-Allow local variables to overlap with each other if they don't
-interfer with each other. (Not implemented right now)
-.TP
-.B -fdarkplaces-string-table-bug
+.It Fl W Ns Cm unknown-attribute
+Warn on an unknown attribute. The warning will inlclude only the first
+token inside the enclosing attribute-brackets. This may change when
+the actual attribute syntax is better defined.
+.It Fl W Ns Cm reserved-names
+Warn when using reserved names such as
+.Ql nil Ns .
+.It Fl W Ns Cm uninitialized-constant
+Warn about global constants (using the
+.Ql const
+keyword) with no
+assigned value.
+.It Fl W Ns Cm uninitialized-global
+Warn about global variables with no initializing value. This is off by
+default, and is added mostly to help find null-values which are
+supposed to be replaced by the untyped 'nil' constant.
+.It Fl W Ns Cm different-qualifiers
+Warn when a variables is redeclared with a different qualifier. For
+example when redeclaring a variable as \'var\' which was previously
+marked \'const\'.
+.It Fl W Ns Cm different-attributes
+Similar to the above but for attributes like
+.Ql [[noreturn]] Ns .
+.It Fl W Ns Cm deprecated
+Warn when a function is marked with the attribute
+"[[deprecated]]". This flag enables a warning on calls to functions
+marked as such.
+.It Fl W Ns Cm parenthesis
+Warn about possible mistakes caused by missing or wrong parenthesis,
+like an assignment in an 'if' condition when there's no additional set
+of parens around the assignment.
+.El
+.Sh COMPILE FLAGS
+.Bl -tag -width Ds
+.It Fl f Ns Cm darkplaces-string-table-bug
Add some additional characters to the string table in order to
compensate for a wrong boundcheck in some specific version of the
darkplaces engine.
-.TP
-.B -fadjust-vector-fields
+.It Fl f Ns Cm adjust-vector-fields
When assigning to field pointers of type \fI.vector\fR the common
behaviour in compilers like \fIfteqcc\fR is to only assign the
x-component of the pointer. This means that you can use the vector as
such, but you cannot use its y and z components directly. This flag
fixes this behaviour. Before using it make sure your code does not
depend on the buggy behaviour.
-.TP
-.B -fftepp
+.It Fl f Ns Cm ftepp
Enable a partially fteqcc-compatible preprocessor. It supports all the
features used in the Xonotic codebase. If you need more, write a
ticket.
-.TP
-.B -frelaxed-switch
+.It Fl f Ns Cm ftepp-predefs
+Enable some predefined macros. This only works in combination with
+\'-fftepp' and is currently not included by '-std=fteqcc'. The
+following macros will be added:
+.Bd -literal -offset indent
+__LINE__
+__FILE__
+__COUNTER__
+__COUNTER_LAST__
+__RANDOM__
+__RANDOM_LAST__
+__DATE__
+__TIME__
+__FUNC__
+.Ed
+.Pp
+Note that
+.Li __FUNC__
+is not actually a preprocessor macro, but is recognized by the parser
+even with the preprocessor disabled.
+.Pp
+Note that fteqcc also defines
+.Li __NULL__
+which becomes the first global. Assigning it to a vector does not
+yield the same result as in gmqcc where
+.Li __NULL__
+is defined to
+.Li nil
+(See
+.Fl f Ns Cm untyped-nil
+), which will cause the vector to be zero in all components. With fteqcc
+only the first component will be 0, while the other two will become
+the first to of the global return value. This behavior is odd and
+relying on it should be discouraged, and thus is not supported by
+gmqcc.
+.It Fl f Ns Cm relaxed-switch
Allow switch cases to use non constant variables.
-.TP
-.B -fshort-logic
+.It Fl f Ns Cm short-logic
Perform early out in logical AND and OR expressions. The final result
will be either a 0 or a 1, see the next flag for more possibilities.
-.TP
-.B -fperl-logic
+.It Fl f Ns Cm perl-logic
In many languages, logical expressions perform early out in a special
way: If the left operand of an AND yeilds true, or the one of an OR
yields false, the complete expression evaluates to the right side.
-Thus \fItrue && 5\fI evaluates to 5 rather than 1.
-.TP
-.B -ftranslatable-strings
-Enable the underscore intrinsic: Using \fI_("A string constant")\fR
+Thus
+.Ql true && 5
+evaluates to 5 rather than 1.
+.It Fl f Ns Cm translatable-strings
+Enable the underscore intrinsic: Using
+.Ql _("A string constant")
will cause the string immediate to get a name with a "dotranslate_"
prefix. The darkplaces engine recognizes these and translates them in
a way similar to how gettext works.
-.TP
-.B -finitialized-nonconstants
+.It Fl f Ns Cm initialized-nonconstants
Don't implicitly convert initialized variables to constants. With this
flag, the \fIconst\fR keyword is required to make a constant.
-.TP
-.B -fassign-function-types
+.It Fl f Ns Cm assign-function-types
If this flag is not set, (and it is set by default in the qcc and
fteqcc standards), assigning function pointers of mismatching
signatures will result in an error rather than a warning.
-.TP
-.B -flno
+.It Fl f Ns Cm lno
Produce a linenumber file along with the output .dat file.
-.TP
-.B -fcorrect-ternary
+.It Fl f Ns Cm correct-ternary
Use C's operator precedence for ternary expressions. Unless your code
depends on fteqcc-compatible behaviour, you'll want to use thi
soption.
+.It Fl f Ns Cm single-vector-defs
+Normally vectors generate 4 defs, once for the vector, and once for
+its components with _x, _y, _z suffixes. This option
+prevents components from being listed.
+.It Fl f Ns Cm correct-logic
+Most QC compilers translate
+.Ql if(a_vector)
+directly as an IF on the
+vector, which means only the x-component is checked. This option causes
+vectors to be cast to actual booleans via a NOT_V and, if necessary, a
+NOT_F chained to it.
+.Bd -literal -offset indent
+if (a_vector) // becomes
+if not(!a_vector)
+// likewise
+a = a_vector && a_float // becomes
+a = !!a_vector && a_float
+.Ed
+.It Fl f Ns Cm true-empty-strings
+An empty string is considered to be true everywhere. The NOT_S
+instruction usually considers an empty string to be false, this option
+effectively causes the unary not in strings to use NOT_F instead.
+.It Fl f Ns Cm false-empty-strings
+An empty string is considered to be false everywhere. This means loops
+and if statements which depend on a string will perform a NOT_S
+instruction on the string before using it.
+.It Fl f Ns Cm utf8
+Enable utf8 characters. This allows utf-8 encoded character constants,
+and escape sequence codepoints in the valid utf-8 range. Effectively
+enabling escape sequences like '\\{x2211}'.
+.It Fl f Ns Cm bail-on-werror
+When a warning is treated as an error, and this option is set (which
+it is by default), it is like any other error and will cause
+compilation to stop. When disabling this flag by using
+\-fno-bail-on-werror, compilation will continue until the end, but no
+output is generated. Instead the first such error message's context is
+shown.
+.It Fl f Ns Cm loop-labels
+Allow loops to be labeled, and allow 'break' and 'continue' to take an
+optional label to decide which loop to actually jump out of or
+continue.
+.Bd -literal -offset indent
+for :outer (i = 0; i < n; ++i) {
+ while (inner) {
+ ...;
+ if (something)
+ continue outer;
+ }
+}
+.Ed
+.It Fl f Ns Cm untyped-nil
+Adds a global named 'nil' which is of no type and can be assigned to
+anything. No typechecking will be performed on assignments. Assigning
+to it is forbidden, using it in any other kind of expression is also
+not allowed.
+.sp
+Note that this is different from fteqcc's __NULL__: In fteqcc,
+__NULL__ maps to the integer written as '0i'. It's can be assigned to
+function pointers and integers, but it'll error about invalid
+instructions when assigning it to floats without enabling the FTE
+instruction set. There's also a bug which allows it to be assigned to
+vectors, for which the source will be the global at offset 0, meaning
+the vector's y and z components will contain the OFS_RETURN x and y
+components.
+.sp
+In that gmqcc the nil global is an actual global filled with zeroes,
+and can be assigned to anything including fields, vectors or function
+pointers, and they end up becoming zeroed.
+.It Fl f Ns Cm permissive
+Various effects, usually to weaken some conditions.
+.Bl -tag -width indent -offset indent
+.It with Fl f Ns Cm untyped-nil
+Allow local variables named
+.Ql nil Ns .
+(This will not allow declaring a global of that name.)
+.El
+.It Fl f Ns Cm variadic-args
+Allow variadic parameters to be accessed by QC code. This can be
+achieved via the '...' function, which takes a parameter index and a
+typename.
+.Pp
+Example:
+.Bd -literal -offset indent
+void vafunc(string...count) {
+ float i;
+ for (i = 0; i < count; ++i)
+ print(...(i, string), "\\n");
+}
+.Ed
+.It Fl f Ns Cm legacy-vector-maths
+Most Quake VMs, including the one from FTEQW or up till recently
+Darkplaces, do not cope well with vector instructions with overlapping
+input and output. This option will avoid producing such code.
+.It Fl f Ns Cm expressions-for-builtins
+Usually builtin-numbers are just immediate constants. With this flag
+expressions can be used, as long as they are compile-time constant.
+.Pp
+Example:
+.Bd -literal -offset indent
+void printA() = #1; // the usual way
+void printB() = #2-1; // with a constant expression
+.Ed
+.El
+.Sh OPTIMIZATIONS
+.Bl -tag -width Ds
+.It Fl O Ns Cm peephole
+Some general peephole optimizations. For instance the code `a = b + c`
+typically generates 2 instructions, an ADD and a STORE. This
+optimization removes the STORE and lets the ADD write directly into A.
+.It Fl O Ns Cm tail-recursion
+Tail recursive function calls will be turned into loops to avoid the
+overhead of the CALL and RETURN instructions.
+.It Fl O Ns Cm overlap-locals
+Make all functions which use neither local arrays nor have locals
+which are seen as possibly uninitialized use the same local section.
+This should be pretty safe compared to other compilers which do not
+check for uninitialized values properly. The problem is that there's
+QC code out there which really doesn't initialize some values. This is
+fine as long as this kind of optimization isn't used, but also, only
+as long as the functions cannot be called in a recursive manner. Since
+it's hard to know whether or not an array is actually fully
+initialized, especially when initializing it via a loop, we assume
+functions with arrays to be too dangerous for this optimization.
+.It Fl O Ns Cm local-temps
+This promotes locally declared variables to "temps". Meaning when a
+temporary result of an operation has to be stored somewhere, a local
+variable which is not 'alive' at that point can be used to keep the
+result. This can reduce the size of the global section.
+This will not have declared variables overlap, even if it was
+possible.
+.It Fl O Ns Cm global-temps
+Causes temporary values which do not need to be backed up on a CALL to
+not be stored in the function's locals-area. With this, a CALL to a
+function may need to back up fewer values and thus execute faster.
+.It Fl O Ns Cm strip-constant-names
+Don't generate defs for immediate values or even declared constants.
+Meaning variables which are implicitly constant or qualified as such
+using the 'const' keyword.
+.It Fl O Ns Cm overlap-strings
+Aggressively reuse strings in the string section. When a string should
+be added which is the trailing substring of an already existing
+string, the existing string's tail will be returned instead of the new
+string being added.
+.Pp
+For example the following code will only generate 1 string:
+.Bd -literal -offset indent
+print("Hell you!\\n");
+print("you!\\n"); // trailing substring of "Hello you!\\n"
+.Ed
+.Pp
+There's however one limitation. Strings are still processed in order,
+so if the above print statements were reversed, this optimization
+would not happen.
+.It Fl O Ns Cm call-stores
+By default, all parameters of a CALL are copied into the
+parameter-globals right before the CALL instructions. This is the
+easiest and safest way to translate calls, but also adds a lot of
+unnecessary copying and unnecessary temporary values. This
+optimization makes operations which are used as a parameter evaluate
+directly into the parameter-global if that is possible, which is when
+there's no other CALL instruction in between.
+.It Fl O Ns Cm void-return
+Usually an empty RETURN instruction is added to the end of a void
+typed function. However, additionally after every function a DONE
+instruction is added for several reasons. (For example the qcvm's
+disassemble switch uses it to know when the function ends.). This
+optimization replaces that last RETURN with DONE rather than adding
+the DONE additionally.
+.It Fl O Ns Cm vector-components
+Because traditional QC code doesn't allow you to access individual
+vector components of a computed vector without storing it in a local
+first, sometimes people multiply it by a constant like
+.Ql '0 1 0'
+to get,
+in this case, the y component of a vector. This optimization will turn
+such a multiplication into a direct component access. If the factor is
+anything other than 1, a float-multiplication will be added, which is
+still faster than a vector multiplication.
+.El
+.Sh CONFIG
+The configuration file is similar to regular .ini files. Comments
+start with hashtags or semicolons, sections are written in square
+brackets and in each section there can be arbitrary many key-value
+pairs.
+.Pp
+There are 3 sections currently:
+.Ql flags Ns ,
+.Ql warnings Ns ,
+.Ql optimizations Ns .
+They contain a list of boolean values of the form
+.Ql VARNAME = true
+or
+.Ql VARNAME = false Ns .
+The variable names are the same as for the
+corresponding
+.Fl W , Fl f
+or
+.Fl O
+flag written with only capital letters and
+dashes replaced by underscores.
+.Pp
+Here's an example:
+.Bd -literal -offset indent
+# a GMQCC configuration file
+[flags]
+ FTEPP = true
+ ADJUST_VECTOR_FIELDS = false
+ LNO = true
+
+[warnings]
+ UNUSED_VARIABLE = false
+ USED_UNINITIALIZED = true
+
+[optimizations]
+ PEEPHOLE = true
+ TAIL_RECURSION = true
+.Ed
+.Sh FILES
+.Bl -tag -width Ds
+.It gmqcc.ini.example
+A documented example for a gmqcc.ini file.
+.El
+.Sh SEE ALSO
+.Xr qcvm 1
+.Sh AUTHOR
+See <http://graphitemaster.github.com/gmqcc>.
+.Sh BUGS
+Currently the '-fftepp-predefs' flag is not included by '-std=fteqcc',
+partially because it is not entirely conformant to fteqcc.
+.Pp
+Please report bugs on <http://github.com/graphitemaster/gmqcc/issues>,
+or see <http://graphitemaster.github.com/gmqcc> on how to contact us.
projects / xonotic / gmqcc.git / blobdiff