| =pod | |
| =head1 NAME | |
| opt - LLVM optimizer | |
| =head1 SYNOPSIS | |
| B<opt> [I<options>] [I<filename>] | |
| =head1 DESCRIPTION | |
| The B<opt> command is the modular LLVM optimizer and analyzer. It takes LLVM | |
| source files as input, runs the specified optimizations or analyses on it, and then | |
| outputs the optimized file or the analysis results. The function of | |
| B<opt> depends on whether the B<-analyze> option is given. | |
| When B<-analyze> is specified, B<opt> performs various analyses of the input | |
| source. It will usually print the results on standard output, but in a few | |
| cases, it will print output to standard error or generate a file with the | |
| analysis output, which is usually done when the output is meant for another | |
| program. | |
| While B<-analyze> is I<not> given, B<opt> attempts to produce an optimized | |
| output file. The optimizations available via B<opt> depend upon what | |
| libraries were linked into it as well as any additional libraries that have | |
| been loaded with the B<-load> option. Use the B<-help> option to determine | |
| what optimizations you can use. | |
| If I<filename> is omitted from the command line or is I<->, B<opt> reads its | |
| input from standard input. Inputs can be in either the LLVM assembly language | |
| format (.ll) or the LLVM bitcode format (.bc). | |
| If an output filename is not specified with the B<-o> option, B<opt> | |
| writes its output to the standard output. | |
| =head1 OPTIONS | |
| =over | |
| =item B<-f> | |
| Enable binary output on terminals. Normally, B<opt> will refuse to | |
| write raw bitcode output if the output stream is a terminal. With this option, | |
| B<opt> will write raw bitcode regardless of the output device. | |
| =item B<-help> | |
| Print a summary of command line options. | |
| =item B<-o> I<filename> | |
| Specify the output filename. | |
| =item B<-S> | |
| Write output in LLVM intermediate language (instead of bitcode). | |
| =item B<-{passname}> | |
| B<opt> provides the ability to run any of LLVM's optimization or analysis passes | |
| in any order. The B<-help> option lists all the passes available. The order in | |
| which the options occur on the command line are the order in which they are | |
| executed (within pass constraints). | |
| =item B<-std-compile-opts> | |
| This is short hand for a standard list of I<compile time optimization> passes. | |
| This is typically used to optimize the output from the llvm-gcc front end. It | |
| might be useful for other front end compilers as well. To discover the full set | |
| of options available, use the following command: | |
| llvm-as < /dev/null | opt -std-compile-opts -disable-output -debug-pass=Arguments | |
| =item B<-disable-inlining> | |
| This option is only meaningful when B<-std-compile-opts> is given. It simply | |
| removes the inlining pass from the standard list. | |
| =item B<-disable-opt> | |
| This option is only meaningful when B<-std-compile-opts> is given. It disables | |
| most, but not all, of the B<-std-compile-opts>. The ones that remain are | |
| B<-verify>, B<-lower-setjmp>, and B<-funcresolve>. | |
| =item B<-strip-debug> | |
| This option causes opt to strip debug information from the module before | |
| applying other optimizations. It is essentially the same as B<-strip> but it | |
| ensures that stripping of debug information is done first. | |
| =item B<-verify-each> | |
| This option causes opt to add a verify pass after every pass otherwise specified | |
| on the command line (including B<-verify>). This is useful for cases where it | |
| is suspected that a pass is creating an invalid module but it is not clear which | |
| pass is doing it. The combination of B<-std-compile-opts> and B<-verify-each> | |
| can quickly track down this kind of problem. | |
| =item B<-profile-info-file> I<filename> | |
| Specify the name of the file loaded by the -profile-loader option. | |
| =item B<-stats> | |
| Print statistics. | |
| =item B<-time-passes> | |
| Record the amount of time needed for each pass and print it to standard | |
| error. | |
| =item B<-debug> | |
| If this is a debug build, this option will enable debug printouts | |
| from passes which use the I<DEBUG()> macro. See the B<LLVM Programmer's | |
| Manual>, section I<#DEBUG> for more information. | |
| =item B<-load>=I<plugin> | |
| Load the dynamic object I<plugin>. This object should register new optimization | |
| or analysis passes. Once loaded, the object will add new command line options to | |
| enable various optimizations or analyses. To see the new complete list of | |
| optimizations, use the B<-help> and B<-load> options together. For example: | |
| opt -load=plugin.so -help | |
| =item B<-p> | |
| Print module after each transformation. | |
| =back | |
| =head1 EXIT STATUS | |
| If B<opt> succeeds, it will exit with 0. Otherwise, if an error | |
| occurs, it will exit with a non-zero value. | |
| =head1 AUTHORS | |
| Maintained by the LLVM Team (L<http://llvm.org/>). | |
| =cut |