\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
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}'.
+.TP
+.B -fbail-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.
+.TP
+.B -floop-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.
+.sp
+.in +4
+.nf
+for :outer (i = 0; i < n; ++i) {
+ while (inner) {
+ ...;
+ if (something)
+ continue outer;
+ }
+}
+.fi
+.in
.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.
-This optimization will not happen for MUL_VF or MUL_FV if the target
-is the float operand.
.TP
.B -Otail-recursion
Tail recursive function calls will be turned into loops to avoid the
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