llvm/docs/CommandGuide/llc.html
Chris Lattner 15a2986107 document the -march=c option
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<title>LLVM: llc tool</title>
<body bgcolor=white>
<center><h1>LLVM: <tt>llc</tt> tool</h1></center>
<HR>
<h3>NAME</h3>
<tt>llc</tt>
<h3>SYNOPSIS</h3>
<tt>llc [options] [filename]</tt>
<h3>DESCRIPTION</h3>
The <tt>llc</tt> command compiles LLVM bytecode into assembly language for a
specified architecture. The assembly language output can then be passed through
a native assembler and linker to generate native code.
<p>
The choice of architecture for the output assembly code is determined as
follows:
<ul>
<li>
If the user has specified an architecture with the -m option, use that
architecture.
<p>
<li>
Examine the input LLVM bytecode file:
<ul>
<li>
If it specifies little endian and a pointer size of 32 bits, select the
x86 architecture.
<p>
<li>
If it specifies big endian and a pointer size of 64 bit pointers,
select the SparcV9 architecture.
</ul>
<p>
<li>
If <tt>llc</tt> was compiled on an architecture for which it can
generate code, select the architecture upon which <tt>llc</tt> was
compiled.
<p>
<li>
Print a message to the user asking him or her to specify the output
architecture explicitly.
</ul>
<p>
If filename is not specified, or if filename is -, <tt>llc</tt> reads its input
from standard input. Otherwise, it will read its input from filename.
<p>
If the -o option is left unspecified, then <tt>llc</tt> will send its output to standard
output if the input is from standard input. If the -o option specifies -, then
the output will also be sent to standard output.
<p>
If no -o option is specified and an input file other than - is specified, then
<tt>llc</tt> creates the output filename as follows:
<ul>
<li>
If the file ends in .bc, then the .bc suffix is removed, and the .s suffix
is appended.
<p>
<li>
Otherwise, the .s suffix is appended to the input filename.
</ul>
<h3>
OPTIONS
</h3>
<ul>
<li>-f
<br>
Overwrite output files
<p>
<li>-m&lt;arch&gt;
<br>
Specify the architecture for which to generate assembly. Valid
architectures are:
<dl compact>
<di> x86
<dd>IA-32 (Pentium and above)</dd>
<di> sparc
<dd>SPARC V9</dd>
<di> c
<dd>Emit C code</dd>
</dl>
<p>
<li>-o &lt;filename&gt;
<br>
Specify the output filename.
<p>
<li> -help
<br>
Print a summary of command line options.
<p>
<li> -stats
<br>
Print statistics.
<p>
<li> -time-passes
<br>
Record the amount of time needed for each pass and print it to standard
error.
<p>
</ul>
<h4>X86 Specific Options</h4>
<ul>
<li>-disable-fp-elim
<br>
Disable frame pointer elimination optimization.
<p>
<li>-disable-pattern-isel
<br>
Use the 'simple' X86 instruction selector (the default).
<p>
<li>-print-machineinstrs
<br>
Print generated machine code.
<p>
<li>-regalloc=&lt;ra&gt;
<br>
Specify the register allocator to use. The default is <i>simple</i>.
Valid register allocators are:
<dl compact>
<di> simple
<dd>Very simple register allocator</dd>
<di> local
<dd>Local register allocator</dd>
</dl>
<p>
</ul>
<h4>Sparc Specific Options</h4>
<ul>
<li>-disable-peephole
<br>
Disable peephole optimization pass.
<p>
<li>-disable-sched
<br>
Disable local scheduling pass.
<p>
<li>-disable-strip
<br>
Do not strip the LLVM bytecode included in executable.
<p>
<li>-enable-maps
<br>
Emit LLVM-to-MachineCode mapping info to assembly.
<p>
</ul>
<h3>EXIT STATUS</h3>
If <tt>llc</tt> succeeds, it will exit with 0. Otherwise, if an error occurs,
it will exit with a non-zero value.
<h3>
SEE ALSO
</h3>
<a href="lli.html"><tt>lli</tt></a>
<HR>
Maintained by the <a href="http://llvm.cs.uiuc.edu">LLVM Team</a>.
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