=head1 DESCRIPTION
-The B<llc> command compiles LLVM bytecode into assembly language for a
+The B<llc> command compiles LLVM source inputs 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.
+a native assembler and linker to generate a native executable.
-The choice of architecture for the output assembly code is automatically
-determined from the input bytecode file, unless a B<-m> option is used to override
+The choice of architecture for the output assembly code is automatically
+determined from the input file, unless the B<-march> option is used to override
the default.
=head1 OPTIONS
-If I<filename> is - or omitted, B<llc> reads LLVM bytecode from standard input.
-Otherwise, it will read LLVM bytecode from I<filename>.
+If I<filename> is - or omitted, B<llc> reads from standard input. Otherwise, it
+will from I<filename>. Inputs can be in either the LLVM assembly language
+format (.ll) or the LLVM bitcode format (.bc).
If the B<-o> option is omitted, then B<llc> will send its output to standard
output if the input is from standard input. If the B<-o> option specifies -,
Other B<llc> options are as follows:
-=over
-
-=item B<-f>
+=head2 End-user Options
-Overwrite output files. By default, B<llc> will refuse to overwrite
-an output file which already exists.
+=over
-=item B<-march>=I<arch>
+=item B<-help>
-Specify the architecture for which to generate assembly. Valid
-architectures are:
+Print a summary of command line options.
-=over
+=item B<-O>=I<uint>
-=item I<x86>
+Generate code at different optimization levels. These correspond to the I<-O0>,
+I<-O1>, I<-O2>, I<-O3>, and I<-O4> optimization levels used by B<llvm-gcc> and
+B<clang>.
-Intel IA-32 (Pentium and above)
+=item B<-mtriple>=I<target triple>
-=item I<ppc32>
+Override the target triple specified in the input file with the specified
+string.
-32-bit PowerPC (MacOS X, 32-bit ABI)
+=item B<-march>=I<arch>
-=item I<sparcv9>
+Specify the architecture for which to generate assembly, overriding the target
+encoded in the input file. See the output of B<llc -help> for a list of
+valid architectures. By default this is inferred from the target triple or
+autodetected to the current architecture.
-64-bit SPARC V9
+=item B<-mcpu>=I<cpuname>
-=item I<c>
+Specify a specific chip in the current architecture to generate code for.
+By default this is inferred from the target triple and autodetected to
+the current architecture. For a list of available CPUs, use:
+B<llvm-as E<lt> /dev/null | llc -march=xyz -mcpu=help>
-Emit C code, not assembly
+=item B<-mattr>=I<a1,+a2,-a3,...>
-=back
+Override or control specific attributes of the target, such as whether SIMD
+operations are enabled or not. The default set of attributes is set by the
+current CPU. For a list of available attributes, use:
+B<llvm-as E<lt> /dev/null | llc -march=xyz -mattr=help>
=item B<--disable-fp-elim>
Disable frame pointer elimination optimization.
+=item B<--disable-excess-fp-precision>
+
+Disable optimizations that may produce excess precision for floating point.
+Note that this option can dramatically slow down code on some systems
+(e.g. X86).
+
+=item B<--enable-unsafe-fp-math>
+
+Enable optimizations that make unsafe assumptions about IEEE math (e.g. that
+addition is associative) or may not work for all input ranges. These
+optimizations allow the code generator to make use of some instructions which
+would otherwise not be usable (such as fsin on X86).
+
=item B<--enable-correct-eh-support>
Instruct the B<lowerinvoke> pass to insert code for correct exception handling
support. This is expensive and is by default omitted for efficiency.
-=item B<--help>
-
-Print a summary of command line options.
-
=item B<--stats>
Print statistics recorded by code-generation passes.
Record the amount of time needed for each pass and print a report to standard
error.
+=item B<--load>=F<dso_path>
+
+Dynamically load F<dso_path> (a path to a dynamically shared object) that
+implements an LLVM target. This will permit the target name to be used with the
+B<-march> option so that code can be generated for that target.
+
+=back
+
+=head2 Tuning/Configuration Options
+
+=over
+
=item B<--print-machineinstrs>
Print generated machine code between compilation phases (useful for debugging).
=back
-=head2 SPARCV9-specific Options
-
-=over
-
-=item B<--disable-peephole>
-
-Disable peephole optimization pass.
-
-=item B<--disable-sched>
-
-Disable local scheduling pass.
-
-=back
-
=head1 EXIT STATUS
If B<llc> succeeds, it will exit with 0. Otherwise, if an error occurs,
=head1 AUTHORS
-Maintained by the LLVM Team (L<http://llvm.cs.uiuc.edu>).
+Maintained by the LLVM Team (L<http://llvm.org>).
=cut
projects / oota-llvm.git / blobdiff