1 opt - LLVM optimizer 2 ==================== 3 4 SYNOPSIS 5 -------- 6 7 :program:`opt` [*options*] [*filename*] 8 9 DESCRIPTION 10 ----------- 11 12 The :program:`opt` command is the modular LLVM optimizer and analyzer. It 13 takes LLVM source files as input, runs the specified optimizations or analyses 14 on it, and then outputs the optimized file or the analysis results. The 15 function of :program:`opt` depends on whether the :option:`-analyze` option is 16 given. 17 18 When :option:`-analyze` is specified, :program:`opt` performs various analyses 19 of the input source. It will usually print the results on standard output, but 20 in a few cases, it will print output to standard error or generate a file with 21 the analysis output, which is usually done when the output is meant for another 22 program. 23 24 While :option:`-analyze` is *not* given, :program:`opt` attempts to produce an 25 optimized output file. The optimizations available via :program:`opt` depend 26 upon what libraries were linked into it as well as any additional libraries 27 that have been loaded with the :option:`-load` option. Use the :option:`-help` 28 option to determine what optimizations you can use. 29 30 If ``filename`` is omitted from the command line or is "``-``", :program:`opt` 31 reads its input from standard input. Inputs can be in either the LLVM assembly 32 language format (``.ll``) or the LLVM bitcode format (``.bc``). 33 34 If an output filename is not specified with the :option:`-o` option, 35 :program:`opt` writes its output to the standard output. 36 37 OPTIONS 38 ------- 39 40 .. option:: -f 41 42 Enable binary output on terminals. Normally, :program:`opt` will refuse to 43 write raw bitcode output if the output stream is a terminal. With this option, 44 :program:`opt` will write raw bitcode regardless of the output device. 45 46 .. option:: -help 47 48 Print a summary of command line options. 49 50 .. option:: -o <filename> 51 52 Specify the output filename. 53 54 .. option:: -S 55 56 Write output in LLVM intermediate language (instead of bitcode). 57 58 .. option:: -{passname} 59 60 :program:`opt` provides the ability to run any of LLVM's optimization or 61 analysis passes in any order. The :option:`-help` option lists all the passes 62 available. The order in which the options occur on the command line are the 63 order in which they are executed (within pass constraints). 64 65 .. option:: -std-compile-opts 66 67 This is short hand for a standard list of *compile time optimization* passes. 68 It might be useful for other front end compilers as well. To discover the 69 full set of options available, use the following command: 70 71 .. code-block:: sh 72 73 llvm-as < /dev/null | opt -std-compile-opts -disable-output -debug-pass=Arguments 74 75 .. option:: -disable-inlining 76 77 This option is only meaningful when :option:`-std-compile-opts` is given. It 78 simply removes the inlining pass from the standard list. 79 80 .. option:: -disable-opt 81 82 This option is only meaningful when :option:`-std-compile-opts` is given. It 83 disables most, but not all, of the :option:`-std-compile-opts`. The ones that 84 remain are :option:`-verify`, :option:`-lower-setjmp`, and 85 :option:`-funcresolve`. 86 87 .. option:: -strip-debug 88 89 This option causes opt to strip debug information from the module before 90 applying other optimizations. It is essentially the same as :option:`-strip` 91 but it ensures that stripping of debug information is done first. 92 93 .. option:: -verify-each 94 95 This option causes opt to add a verify pass after every pass otherwise 96 specified on the command line (including :option:`-verify`). This is useful 97 for cases where it is suspected that a pass is creating an invalid module but 98 it is not clear which pass is doing it. The combination of 99 :option:`-std-compile-opts` and :option:`-verify-each` can quickly track down 100 this kind of problem. 101 102 .. option:: -stats 103 104 Print statistics. 105 106 .. option:: -time-passes 107 108 Record the amount of time needed for each pass and print it to standard 109 error. 110 111 .. option:: -debug 112 113 If this is a debug build, this option will enable debug printouts from passes 114 which use the ``DEBUG()`` macro. See the `LLVM Programmer's Manual 115 <../ProgrammersManual.html>`_, section ``#DEBUG`` for more information. 116 117 .. option:: -load=<plugin> 118 119 Load the dynamic object ``plugin``. This object should register new 120 optimization or analysis passes. Once loaded, the object will add new command 121 line options to enable various optimizations or analyses. To see the new 122 complete list of optimizations, use the :option:`-help` and :option:`-load` 123 options together. For example: 124 125 .. code-block:: sh 126 127 opt -load=plugin.so -help 128 129 .. option:: -p 130 131 Print module after each transformation. 132 133 EXIT STATUS 134 ----------- 135 136 If :program:`opt` succeeds, it will exit with 0. Otherwise, if an error 137 occurs, it will exit with a non-zero value. 138 139
