\fBgmqcc\fR 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
+\fBgmqcc\fR mostly tries to mimic gcc's commandline handling, though
there are also traditional long-options available.
.TP
.B "-h, --help"
List all possible optimizations and the optimization level they're
activated at.
.TP
+.BR -q ", " --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.
+.TP
.BI -W warning "\fR, " "" -Wno- warning
Enable or disable a warning.
.TP
-f\fIno-\fRcorrect-ternary
.fi
.in
+.TP
+.B "-dump"
+DEBUG OPTION. Print the code's intermediate representation before the
+optimization and finalization passes to stdout before generating the
+binary.
+.TP
+.B "-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.
.SH COMPILE WARNINGS
.TP
.B -Wunused-variable
the actual attribute syntax is better defined.
.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
Add some additional characters to the string table in order to
compensate for a wrong boundcheck in some specific version of the
features used in the Xonotic codebase. If you need more, write a
ticket.
.TP
+.B -fftepp-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:
+.in +4
+.nf
+__LINE__
+__FILE__
+__COUNTER__
+__COUNTER_LAST__
+__RANDOM__
+__RANDOM_LAST__
+.fi
+.in
+Note that fteqcc also defines __FUNC__, __TIME__, __DATE__ and
+__NULL__, which are not yet implemented.
+.TP
.B -frelaxed-switch
Allow switch cases to use non constant variables.
.TP
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.
+.TP
+.B -futf8
+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}'.
+.SH OPTIMIZATIONS
+.TP
+.B -Opeephole
+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.
+.TP
+.B -Otail-recursion
+Tail recursive function calls will be turned into loops to avoid the
+overhead of the CALL and RETURN instructions.
+.TP
+.B -Ooverlap-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.
+.TP
+.B -Olocal-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.
+.TP
+.B -Oglobal-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.
+.TP
+.B -Ostrip-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.
+.TP
+.B -Ooverlap-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.
+
+For example the following code will only generate 1 string:
+
+.in +4
+.nf
+print("Hell you!\\n");
+print("you!\\n"); // trailing substring of "Hello you!\\n"
+.fi
+.in
+There's however one limitation. Strings are still processed in order,
+so if the above print statements were reversed, this optimization
+would not happen.
+.TP
+.B -Ocall-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.
+.TP
+.B -Ovoid-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.
.SH CONFIG
The configuration file is similar to regular .ini files. Comments
start with hashtags or semicolons, sections are written in square
.fi
.in
.SH BUGS
+Currently the '-fftepp-predefs' flag is not included by '-std=fteqcc',
+partially because it is not entirely conformant to fteqcc.
+.sp
+
Please report bugs on <http://github.com/graphitemaster/gmqcc/issues>,
or see <http://graphitemaster.github.com/gmqcc> on how to contact us.
.SH FILES
projects / xonotic / gmqcc.git / blobdiff