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gerrit-public.fairphone.software / toolchain / llvm-project / 46df6a252a8f8f36381a50a548264f453233d122 / . / llvm / docs / CommandLine.html
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4<head>
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Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]6 <title>CommandLine 2.0 Library Manual</title>
Misha Brukman7120c832003-11-07 18:11:14 +0000[diff] [blame]7 <link rel="stylesheet" href="llvm.css" type="text/css">
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]8</head>
9<body>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]10
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]11<h1>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]12 CommandLine 2.0 Library Manual
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]13</h1>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]14
15<ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]16 <li><a href="#introduction">Introduction</a></li>
17
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]18 <li><a href="#quickstart">Quick Start Guide</a>
19 <ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]20 <li><a href="#bool">Boolean Arguments</a></li>
21 <li><a href="#alias">Argument Aliases</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]22 <li><a href="#onealternative">Selecting an alternative from a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]23 set of possibilities</a></li>
24 <li><a href="#namedalternatives">Named alternatives</a></li>
25 <li><a href="#list">Parsing a list of options</a></li>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]26 <li><a href="#bits">Collecting options as a set of flags</a></li>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]27 <li><a href="#description">Adding freeform text to help output</a></li>
28 </ol></li>
29
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]30 <li><a href="#referenceguide">Reference Guide</a>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]31 <ol>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]32 <li><a href="#positional">Positional Arguments</a>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]33 <ul>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]34 <li><a href="#--">Specifying positional options with hyphens</a></li>
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]35 <li><a href="#getPosition">Determining absolute position with
36 getPosition</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]37 <li><a href="#cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]38 modifier</a></li>
39 </ul></li>
40
41 <li><a href="#storage">Internal vs External Storage</a></li>
42
43 <li><a href="#attributes">Option Attributes</a></li>
44
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]45 <li><a href="#modifiers">Option Modifiers</a>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]46 <ul>
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]47 <li><a href="#hiding">Hiding an option from <tt>-help</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]48 output</a></li>
49 <li><a href="#numoccurrences">Controlling the number of occurrences
50 required and allowed</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]51 <li><a href="#valrequired">Controlling whether or not a value must be
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]52 specified</a></li>
53 <li><a href="#formatting">Controlling other formatting options</a></li>
54 <li><a href="#misc">Miscellaneous option modifiers</a></li>
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]55 <li><a href="#response">Response files</a></li>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]56 </ul></li>
57
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]58 <li><a href="#toplevel">Top-Level Classes and Functions</a>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]59 <ul>
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]60 <li><a href="#cl::ParseCommandLineOptions">The
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]61 <tt>cl::ParseCommandLineOptions</tt> function</a></li>
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]62 <li><a href="#cl::ParseEnvironmentOptions">The
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]63 <tt>cl::ParseEnvironmentOptions</tt> function</a></li>
Chris Lattnerf1be2882007-12-19 19:48:49 +0000[diff] [blame]64 <li><a href="#cl::SetVersionPrinter">The <tt>cl::SetVersionPrinter</tt>
Reid Spencer0075b2f2006-06-05 17:30:16 +0000[diff] [blame]65 function</a></li>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]66 <li><a href="#cl::opt">The <tt>cl::opt</tt> class</a></li>
67 <li><a href="#cl::list">The <tt>cl::list</tt> class</a></li>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]68 <li><a href="#cl::bits">The <tt>cl::bits</tt> class</a></li>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]69 <li><a href="#cl::alias">The <tt>cl::alias</tt> class</a></li>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]70 <li><a href="#cl::extrahelp">The <tt>cl::extrahelp</tt> class</a></li>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]71 </ul></li>
72
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]73 <li><a href="#builtinparsers">Builtin parsers</a>
74 <ul>
75 <li><a href="#genericparser">The Generic <tt>parser&lt;t&gt;</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]76 parser</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]77 <li><a href="#boolparser">The <tt>parser&lt;bool&gt;</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]78 specialization</a></li>
Dale Johannesen10c5ccc2007-05-22 18:32:34 +0000[diff] [blame]79 <li><a href="#boolOrDefaultparser">The <tt>parser&lt;boolOrDefault&gt;</tt>
80 specialization</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]81 <li><a href="#stringparser">The <tt>parser&lt;string&gt;</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]82 specialization</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]83 <li><a href="#intparser">The <tt>parser&lt;int&gt;</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]84 specialization</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]85 <li><a href="#doubleparser">The <tt>parser&lt;double&gt;</tt> and
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]86 <tt>parser&lt;float&gt;</tt> specializations</a></li>
87 </ul></li>
88 </ol></li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]89 <li><a href="#extensionguide">Extension Guide</a>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]90 <ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]91 <li><a href="#customparser">Writing a custom parser</a></li>
92 <li><a href="#explotingexternal">Exploiting external storage</a></li>
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]93 <li><a href="#dynamicopts">Dynamically adding command line
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]94 options</a></li>
95 </ol></li>
96</ol>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]97
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]98<div class="doc_author">
99 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]100</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]101
102<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]103<h2>
Misha Brukman403ff612003-11-07 19:42:44 +0000[diff] [blame]104 <a name="introduction">Introduction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]105</h2>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]106<!-- *********************************************************************** -->
107
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]108<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]109
110<p>This document describes the CommandLine argument processing library. It will
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]111show you how to use it, and what it can do. The CommandLine library uses a
112declarative approach to specifying the command line options that your program
113takes. By default, these options declarations implicitly hold the value parsed
114for the option declared (of course this <a href="#storage">can be
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]115changed</a>).</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]116
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]117<p>Although there are a <b>lot</b> of command line argument parsing libraries
118out there in many different languages, none of them fit well with what I needed.
119By looking at the features and problems of other libraries, I designed the
120CommandLine library to have the following features:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]121
122<ol>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]123<li>Speed: The CommandLine library is very quick and uses little resources. The
124parsing time of the library is directly proportional to the number of arguments
125parsed, not the the number of options recognized. Additionally, command line
Chris Lattner364e6312003-06-21 21:45:56 +0000[diff] [blame]126argument values are captured transparently into user defined global variables,
127which can be accessed like any other variable (and with the same
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]128performance).</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]129
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]130<li>Type Safe: As a user of CommandLine, you don't have to worry about
131remembering the type of arguments that you want (is it an int? a string? a
132bool? an enum?) and keep casting it around. Not only does this help prevent
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]133error prone constructs, it also leads to dramatically cleaner source code.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]134
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]135<li>No subclasses required: To use CommandLine, you instantiate variables that
136correspond to the arguments that you would like to capture, you don't subclass a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]137parser. This means that you don't have to write <b>any</b> boilerplate
138code.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]139
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]140<li>Globally accessible: Libraries can specify command line arguments that are
141automatically enabled in any tool that links to the library. This is possible
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]142because the application doesn't have to keep a list of arguments to pass to
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]143the parser. This also makes supporting <a href="#dynamicopts">dynamically
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]144loaded options</a> trivial.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]145
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]146<li>Cleaner: CommandLine supports enum and other types directly, meaning that
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]147there is less error and more security built into the library. You don't have to
148worry about whether your integral command line argument accidentally got
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]149assigned a value that is not valid for your enum type.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]150
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]151<li>Powerful: The CommandLine library supports many different types of
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]152arguments, from simple <a href="#boolparser">boolean flags</a> to <a
153href="#cl::opt">scalars arguments</a> (<a href="#stringparser">strings</a>, <a
154href="#intparser">integers</a>, <a href="#genericparser">enums</a>, <a
155href="#doubleparser">doubles</a>), to <a href="#cl::list">lists of
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]156arguments</a>. This is possible because CommandLine is...</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]157
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]158<li>Extensible: It is very simple to add a new argument type to CommandLine.
159Simply specify the parser that you want to use with the command line option when
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]160you declare it. <a href="#customparser">Custom parsers</a> are no problem.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]161
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]162<li>Labor Saving: The CommandLine library cuts down on the amount of grunt work
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]163that you, the user, have to do. For example, it automatically provides a
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]164<tt>-help</tt> option that shows the available command line options for your
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]165tool. Additionally, it does most of the basic correctness checking for
166you.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]167
168<li>Capable: The CommandLine library can handle lots of different forms of
169options often found in real programs. For example, <a
170href="#positional">positional</a> arguments, <tt>ls</tt> style <a
171href="#cl::Grouping">grouping</a> options (to allow processing '<tt>ls
172-lad</tt>' naturally), <tt>ld</tt> style <a href="#cl::Prefix">prefix</a>
173options (to parse '<tt>-lmalloc -L/usr/lib</tt>'), and <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]174href="#cl::ConsumeAfter">interpreter style options</a>.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]175
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]176</ol>
177
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]178<p>This document will hopefully let you jump in and start using CommandLine in
179your utility quickly and painlessly. Additionally it should be a simple
180reference manual to figure out how stuff works. If it is failing in some area
181(or you want an extension to the library), nag the author, <a
182href="mailto:sabre@nondot.org">Chris Lattner</a>.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]183
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]184</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]185
186<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]187<h2>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]188 <a name="quickstart">Quick Start Guide</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]189</h2>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]190<!-- *********************************************************************** -->
191
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]192<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]193
194<p>This section of the manual runs through a simple CommandLine'ification of a
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]195basic compiler tool. This is intended to show you how to jump into using the
196CommandLine library in your own program, and show you some of the cool things it
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]197can do.</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]198
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]199<p>To start out, you need to include the CommandLine header file into your
200program:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]201
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]202<div class="doc_code"><pre>
Andrew Lenharthb720e2c2005-11-14 19:32:05 +0000[diff] [blame]203 #include "llvm/Support/CommandLine.h"
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]204</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]205
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]206<p>Additionally, you need to add this as the first line of your main
207program:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]208
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]209<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]210int main(int argc, char **argv) {
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]211 <a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv);
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]212 ...
213}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]214</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]215
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]216<p>... which actually parses the arguments and fills in the variable
217declarations.</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]218
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]219<p>Now that you are ready to support command line arguments, we need to tell the
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]220system which ones we want, and what type of arguments they are. The CommandLine
Chris Lattner364e6312003-06-21 21:45:56 +0000[diff] [blame]221library uses a declarative syntax to model command line arguments with the
222global variable declarations that capture the parsed values. This means that
223for every command line option that you would like to support, there should be a
224global variable declaration to capture the result. For example, in a compiler,
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]225we would like to support the Unix-standard '<tt>-o &lt;filename&gt;</tt>' option
Chris Lattner364e6312003-06-21 21:45:56 +0000[diff] [blame]226to specify where to put the output. With the CommandLine library, this is
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]227represented like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]228
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]229<a name="value_desc_example"></a>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]230<div class="doc_code"><pre>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]231<a href="#cl::opt">cl::opt</a>&lt;string&gt; OutputFilename("<i>o</i>", <a href="#cl::desc">cl::desc</a>("<i>Specify output filename</i>"), <a href="#cl::value_desc">cl::value_desc</a>("<i>filename</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]232</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]233
NAKAMURA Takumi2a7024f2011-04-11 03:27:31 +0000[diff] [blame]234<p>This declares a global variable &quot;<tt>OutputFilename</tt>&quot; that is used to
235capture the result of the &quot;<tt>o</tt>&quot; argument (first parameter). We specify
236that this is a simple scalar option by using the &quot;<tt><a
237href="#cl::opt">cl::opt</a></tt>&quot; template (as opposed to the <a
238href="#list">&quot;<tt>cl::list</tt> template</a>), and tell the CommandLine library
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]239that the data type that we are parsing is a string.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]240
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]241<p>The second and third parameters (which are optional) are used to specify what
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]242to output for the "<tt>-help</tt>" option. In this case, we get a line that
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]243looks like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]244
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]245<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]246USAGE: compiler [options]
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]247
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]248OPTIONS:
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]249 -help - display available options (-help-hidden for more)
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]250 <b>-o &lt;filename&gt; - Specify output filename</b>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]251</pre></div>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]252
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]253<p>Because we specified that the command line option should parse using the
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]254<tt>string</tt> data type, the variable declared is automatically usable as a
255real string in all contexts that a normal C++ string object may be used. For
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]256example:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]257
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]258<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]259 ...
Chris Lattnera01203e2008-03-30 16:59:21 +0000[diff] [blame]260 std::ofstream Output(OutputFilename.c_str());
261 if (Output.good()) ...
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]262 ...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]263</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]264
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]265<p>There are many different options that you can use to customize the command
266line option handling library, but the above example shows the general interface
267to these options. The options can be specified in any order, and are specified
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]268with helper functions like <a href="#cl::desc"><tt>cl::desc(...)</tt></a>, so
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]269there are no positional dependencies to remember. The available options are
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]270discussed in detail in the <a href="#referenceguide">Reference Guide</a>.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]271
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]272<p>Continuing the example, we would like to have our compiler take an input
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]273filename as well as an output filename, but we do not want the input filename to
274be specified with a hyphen (ie, not <tt>-filename.c</tt>). To support this
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]275style of argument, the CommandLine library allows for <a
276href="#positional">positional</a> arguments to be specified for the program.
277These positional arguments are filled with command line parameters that are not
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]278in option form. We use this feature like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]279
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]280<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]281<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <a href="#cl::init">cl::init</a>("<i>-</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]282</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]283
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]284<p>This declaration indicates that the first positional argument should be
285treated as the input filename. Here we use the <tt><a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]286href="#cl::init">cl::init</a></tt> option to specify an initial value for the
287command line option, which is used if the option is not specified (if you do not
288specify a <tt><a href="#cl::init">cl::init</a></tt> modifier for an option, then
289the default constructor for the data type is used to initialize the value).
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]290Command line options default to being optional, so if we would like to require
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]291that the user always specify an input filename, we would add the <tt><a
292href="#cl::Required">cl::Required</a></tt> flag, and we could eliminate the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]293<tt><a href="#cl::init">cl::init</a></tt> modifier, like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]294
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]295<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]296<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <b><a href="#cl::Required">cl::Required</a></b>);
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]297</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]298
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]299<p>Again, the CommandLine library does not require the options to be specified
300in any particular order, so the above declaration is equivalent to:</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]301
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]302<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]303<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::Required">cl::Required</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]304</pre></div>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]305
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]306<p>By simply adding the <tt><a href="#cl::Required">cl::Required</a></tt> flag,
307the CommandLine library will automatically issue an error if the argument is not
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]308specified, which shifts all of the command line option verification code out of
309your application into the library. This is just one example of how using flags
310can alter the default behaviour of the library, on a per-option basis. By
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]311adding one of the declarations above, the <tt>-help</tt> option synopsis is now
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]312extended to:</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]313
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]314<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]315USAGE: compiler [options] <b>&lt;input file&gt;</b>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]316
317OPTIONS:
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]318 -help - display available options (-help-hidden for more)
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]319 -o &lt;filename&gt; - Specify output filename
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]320</pre></div>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]321
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]322<p>... indicating that an input filename is expected.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]323
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]324<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]325<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]326 <a name="bool">Boolean Arguments</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]327</h3>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]328
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]329<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]330
331<p>In addition to input and output filenames, we would like the compiler example
Dan Gohmandd121d52009-08-25 15:54:01 +0000[diff] [blame]332to support three boolean flags: "<tt>-f</tt>" to force writing binary output to
333a terminal, "<tt>--quiet</tt>" to enable quiet mode, and "<tt>-q</tt>" for
334backwards compatibility with some of our users. We can support these by
335declaring options of boolean type like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]336
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]337<div class="doc_code"><pre>
Dan Gohmandd121d52009-08-25 15:54:01 +0000[diff] [blame]338<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Force ("<i>f</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable binary output on terminals</i>"));
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]339<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet ("<i>quiet</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"));
340<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet2("<i>q</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"), <a href="#cl::Hidden">cl::Hidden</a>);
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]341</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]342
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]343<p>This does what you would expect: it declares three boolean variables
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]344("<tt>Force</tt>", "<tt>Quiet</tt>", and "<tt>Quiet2</tt>") to recognize these
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]345options. Note that the "<tt>-q</tt>" option is specified with the "<a
346href="#cl::Hidden"><tt>cl::Hidden</tt></a>" flag. This modifier prevents it
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]347from being shown by the standard "<tt>-help</tt>" output (note that it is still
348shown in the "<tt>-help-hidden</tt>" output).</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]349
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]350<p>The CommandLine library uses a <a href="#builtinparsers">different parser</a>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]351for different data types. For example, in the string case, the argument passed
352to the option is copied literally into the content of the string variable... we
353obviously cannot do that in the boolean case, however, so we must use a smarter
354parser. In the case of the boolean parser, it allows no options (in which case
355it assigns the value of true to the variable), or it allows the values
356"<tt>true</tt>" or "<tt>false</tt>" to be specified, allowing any of the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]357following inputs:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]358
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]359<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]360 compiler -f # No value, 'Force' == true
361 compiler -f=true # Value specified, 'Force' == true
362 compiler -f=TRUE # Value specified, 'Force' == true
363 compiler -f=FALSE # Value specified, 'Force' == false
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]364</pre></div>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]365
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]366<p>... you get the idea. The <a href="#boolparser">bool parser</a> just turns
367the string values into boolean values, and rejects things like '<tt>compiler
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]368-f=foo</tt>'. Similarly, the <a href="#doubleparser">float</a>, <a
369href="#doubleparser">double</a>, and <a href="#intparser">int</a> parsers work
370like you would expect, using the '<tt>strtol</tt>' and '<tt>strtod</tt>' C
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]371library calls to parse the string value into the specified data type.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]372
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]373<p>With the declarations above, "<tt>compiler -help</tt>" emits this:</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]374
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]375<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]376USAGE: compiler [options] &lt;input file&gt;
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]377
378OPTIONS:
Dan Gohmandd121d52009-08-25 15:54:01 +0000[diff] [blame]379 <b>-f - Enable binary output on terminals</b>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]380 -o - Override output filename
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]381 <b>-quiet - Don't print informational messages</b>
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]382 -help - display available options (-help-hidden for more)
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]383</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]384
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]385<p>and "<tt>compiler -help-hidden</tt>" prints this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]386
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]387<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]388USAGE: compiler [options] &lt;input file&gt;
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]389
390OPTIONS:
Dan Gohmandd121d52009-08-25 15:54:01 +0000[diff] [blame]391 -f - Enable binary output on terminals
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]392 -o - Override output filename
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]393 <b>-q - Don't print informational messages</b>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]394 -quiet - Don't print informational messages
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]395 -help - display available options (-help-hidden for more)
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]396</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]397
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]398<p>This brief example has shown you how to use the '<tt><a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]399href="#cl::opt">cl::opt</a></tt>' class to parse simple scalar command line
400arguments. In addition to simple scalar arguments, the CommandLine library also
401provides primitives to support CommandLine option <a href="#alias">aliases</a>,
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]402and <a href="#list">lists</a> of options.</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]403
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]404</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]405
406<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]407<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]408 <a name="alias">Argument Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]409</h3>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]410
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]411<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]412
413<p>So far, the example works well, except for the fact that we need to check the
414quiet condition like this now:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]415
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]416<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]417...
418 if (!Quiet &amp;&amp; !Quiet2) printInformationalMessage(...);
419...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]420</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]421
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]422<p>... which is a real pain! Instead of defining two values for the same
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]423condition, we can use the "<tt><a href="#cl::alias">cl::alias</a></tt>" class to make the "<tt>-q</tt>"
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]424option an <b>alias</b> for the "<tt>-quiet</tt>" option, instead of providing
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]425a value itself:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]426
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]427<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]428<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Force ("<i>f</i>", <a href="#cl::desc">cl::desc</a>("<i>Overwrite output files</i>"));
429<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet ("<i>quiet</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"));
430<a href="#cl::alias">cl::alias</a> QuietA("<i>q</i>", <a href="#cl::desc">cl::desc</a>("<i>Alias for -quiet</i>"), <a href="#cl::aliasopt">cl::aliasopt</a>(Quiet));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]431</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]432
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]433<p>The third line (which is the only one we modified from above) defines a
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]434"<tt>-q</tt>" alias that updates the "<tt>Quiet</tt>" variable (as specified by
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]435the <tt><a href="#cl::aliasopt">cl::aliasopt</a></tt> modifier) whenever it is
436specified. Because aliases do not hold state, the only thing the program has to
437query is the <tt>Quiet</tt> variable now. Another nice feature of aliases is
438that they automatically hide themselves from the <tt>-help</tt> output
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]439(although, again, they are still visible in the <tt>-help-hidden
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]440output</tt>).</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]441
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]442<p>Now the application code can simply use:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]443
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]444<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]445...
446 if (!Quiet) printInformationalMessage(...);
447...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]448</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]449
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]450<p>... which is much nicer! The "<tt><a href="#cl::alias">cl::alias</a></tt>"
451can be used to specify an alternative name for any variable type, and has many
452uses.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]453
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]454</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]455
456<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]457<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]458 <a name="onealternative">Selecting an alternative from a set of
459 possibilities</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]460</h3>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]461
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]462<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]463
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]464<p>So far we have seen how the CommandLine library handles builtin types like
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]465<tt>std::string</tt>, <tt>bool</tt> and <tt>int</tt>, but how does it handle
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]466things it doesn't know about, like enums or '<tt>int*</tt>'s?</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]467
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]468<p>The answer is that it uses a table-driven generic parser (unless you specify
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]469your own parser, as described in the <a href="#extensionguide">Extension
Reid Spencera39bf3d2004-08-10 16:38:18 +0000[diff] [blame]470Guide</a>). This parser maps literal strings to whatever type is required, and
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]471requires you to tell it what this mapping should be.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]472
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]473<p>Let's say that we would like to add four optimization levels to our
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]474optimizer, using the standard flags "<tt>-g</tt>", "<tt>-O0</tt>",
475"<tt>-O1</tt>", and "<tt>-O2</tt>". We could easily implement this with boolean
476options like above, but there are several problems with this strategy:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]477
478<ol>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]479<li>A user could specify more than one of the options at a time, for example,
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]480"<tt>compiler -O3 -O2</tt>". The CommandLine library would not be able to
481catch this erroneous input for us.</li>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]482
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]483<li>We would have to test 4 different variables to see which ones are set.</li>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]484
485<li>This doesn't map to the numeric levels that we want... so we cannot easily
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]486see if some level &gt;= "<tt>-O1</tt>" is enabled.</li>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]487
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]488</ol>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]489
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]490<p>To cope with these problems, we can use an enum value, and have the
491CommandLine library fill it in with the appropriate level directly, which is
492used like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]493
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]494<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]495enum OptLevel {
496 g, O1, O2, O3
497};
498
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]499<a href="#cl::opt">cl::opt</a>&lt;OptLevel&gt; OptimizationLevel(<a href="#cl::desc">cl::desc</a>("<i>Choose optimization level:</i>"),
500 <a href="#cl::values">cl::values</a>(
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]501 clEnumVal(g , "<i>No optimizations, enable debugging</i>"),
502 clEnumVal(O1, "<i>Enable trivial optimizations</i>"),
503 clEnumVal(O2, "<i>Enable default optimizations</i>"),
504 clEnumVal(O3, "<i>Enable expensive optimizations</i>"),
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]505 clEnumValEnd));
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]506
507...
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]508 if (OptimizationLevel &gt;= O2) doPartialRedundancyElimination(...);
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]509...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]510</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]511
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]512<p>This declaration defines a variable "<tt>OptimizationLevel</tt>" of the
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]513"<tt>OptLevel</tt>" enum type. This variable can be assigned any of the values
514that are listed in the declaration (Note that the declaration list must be
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]515terminated with the "<tt>clEnumValEnd</tt>" argument!). The CommandLine
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]516library enforces
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]517that the user can only specify one of the options, and it ensure that only valid
518enum values can be specified. The "<tt>clEnumVal</tt>" macros ensure that the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]519command line arguments matched the enum values. With this option added, our
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]520help output now is:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]521
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]522<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]523USAGE: compiler [options] &lt;input file&gt;
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]524
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]525OPTIONS:
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]526 <b>Choose optimization level:
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]527 -g - No optimizations, enable debugging
528 -O1 - Enable trivial optimizations
529 -O2 - Enable default optimizations
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]530 -O3 - Enable expensive optimizations</b>
Dan Gohmandd121d52009-08-25 15:54:01 +0000[diff] [blame]531 -f - Enable binary output on terminals
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]532 -help - display available options (-help-hidden for more)
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]533 -o &lt;filename&gt; - Specify output filename
534 -quiet - Don't print informational messages
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]535</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]536
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]537<p>In this case, it is sort of awkward that flag names correspond directly to
538enum names, because we probably don't want a enum definition named "<tt>g</tt>"
539in our program. Because of this, we can alternatively write this example like
540this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]541
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]542<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]543enum OptLevel {
544 Debug, O1, O2, O3
545};
546
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]547<a href="#cl::opt">cl::opt</a>&lt;OptLevel&gt; OptimizationLevel(<a href="#cl::desc">cl::desc</a>("<i>Choose optimization level:</i>"),
548 <a href="#cl::values">cl::values</a>(
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]549 clEnumValN(Debug, "g", "<i>No optimizations, enable debugging</i>"),
550 clEnumVal(O1 , "<i>Enable trivial optimizations</i>"),
551 clEnumVal(O2 , "<i>Enable default optimizations</i>"),
552 clEnumVal(O3 , "<i>Enable expensive optimizations</i>"),
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]553 clEnumValEnd));
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]554
555...
556 if (OptimizationLevel == Debug) outputDebugInfo(...);
557...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]558</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]559
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]560<p>By using the "<tt>clEnumValN</tt>" macro instead of "<tt>clEnumVal</tt>", we
561can directly specify the name that the flag should get. In general a direct
562mapping is nice, but sometimes you can't or don't want to preserve the mapping,
563which is when you would use it.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]564
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]565</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]566
567<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]568<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]569 <a name="namedalternatives">Named Alternatives</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]570</h3>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]571
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]572<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]573
574<p>Another useful argument form is a named alternative style. We shall use this
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]575style in our compiler to specify different debug levels that can be used.
576Instead of each debug level being its own switch, we want to support the
577following options, of which only one can be specified at a time:
578"<tt>--debug-level=none</tt>", "<tt>--debug-level=quick</tt>",
579"<tt>--debug-level=detailed</tt>". To do this, we use the exact same format as
580our optimization level flags, but we also specify an option name. For this
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]581case, the code looks like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]582
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]583<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]584enum DebugLev {
585 nodebuginfo, quick, detailed
586};
587
588// Enable Debug Options to be specified on the command line
Chris Lattner3b8f3da2003-06-03 04:40:06 +0000[diff] [blame]589<a href="#cl::opt">cl::opt</a>&lt;DebugLev&gt; DebugLevel("<i>debug_level</i>", <a href="#cl::desc">cl::desc</a>("<i>Set the debugging level:</i>"),
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]590 <a href="#cl::values">cl::values</a>(
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]591 clEnumValN(nodebuginfo, "none", "<i>disable debug information</i>"),
592 clEnumVal(quick, "<i>enable quick debug information</i>"),
593 clEnumVal(detailed, "<i>enable detailed debug information</i>"),
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]594 clEnumValEnd));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]595</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]596
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]597<p>This definition defines an enumerated command line variable of type "<tt>enum
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]598DebugLev</tt>", which works exactly the same way as before. The difference here
599is just the interface exposed to the user of your program and the help output by
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]600the "<tt>-help</tt>" option:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]601
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]602<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]603USAGE: compiler [options] &lt;input file&gt;
604
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]605OPTIONS:
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]606 Choose optimization level:
607 -g - No optimizations, enable debugging
608 -O1 - Enable trivial optimizations
609 -O2 - Enable default optimizations
610 -O3 - Enable expensive optimizations
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]611 <b>-debug_level - Set the debugging level:
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]612 =none - disable debug information
613 =quick - enable quick debug information
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]614 =detailed - enable detailed debug information</b>
Dan Gohmandd121d52009-08-25 15:54:01 +0000[diff] [blame]615 -f - Enable binary output on terminals
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]616 -help - display available options (-help-hidden for more)
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]617 -o &lt;filename&gt; - Specify output filename
618 -quiet - Don't print informational messages
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]619</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]620
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]621<p>Again, the only structural difference between the debug level declaration and
John Criswella9f34ca2004-11-21 14:34:34 +0000[diff] [blame]622the optimization level declaration is that the debug level declaration includes
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]623an option name (<tt>"debug_level"</tt>), which automatically changes how the
624library processes the argument. The CommandLine library supports both forms so
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]625that you can choose the form most appropriate for your application.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]626
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]627</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]628
629<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]630<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]631 <a name="list">Parsing a list of options</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]632</h3>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]633
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]634<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]635
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]636<p>Now that we have the standard run-of-the-mill argument types out of the way,
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]637lets get a little wild and crazy. Lets say that we want our optimizer to accept
638a <b>list</b> of optimizations to perform, allowing duplicates. For example, we
639might want to run: "<tt>compiler -dce -constprop -inline -dce -strip</tt>". In
640this case, the order of the arguments and the number of appearances is very
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]641important. This is what the "<tt><a href="#cl::list">cl::list</a></tt>"
642template is for. First, start by defining an enum of the optimizations that you
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]643would like to perform:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]644
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]645<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]646enum Opts {
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]647 // 'inline' is a C++ keyword, so name it 'inlining'
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]648 dce, constprop, inlining, strip
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]649};
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]650</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]651
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]652<p>Then define your "<tt><a href="#cl::list">cl::list</a></tt>" variable:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]653
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]654<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]655<a href="#cl::list">cl::list</a>&lt;Opts&gt; OptimizationList(<a href="#cl::desc">cl::desc</a>("<i>Available Optimizations:</i>"),
656 <a href="#cl::values">cl::values</a>(
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]657 clEnumVal(dce , "<i>Dead Code Elimination</i>"),
Misha Brukman373086d2003-05-20 21:01:22 +0000[diff] [blame]658 clEnumVal(constprop , "<i>Constant Propagation</i>"),
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]659 clEnumValN(inlining, "<i>inline</i>", "<i>Procedure Integration</i>"),
660 clEnumVal(strip , "<i>Strip Symbols</i>"),
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]661 clEnumValEnd));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]662</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]663
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]664<p>This defines a variable that is conceptually of the type
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]665"<tt>std::vector&lt;enum Opts&gt;</tt>". Thus, you can access it with standard
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]666vector methods:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]667
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]668<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]669 for (unsigned i = 0; i != OptimizationList.size(); ++i)
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]670 switch (OptimizationList[i])
671 ...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]672</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]673
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]674<p>... to iterate through the list of options specified.</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]675
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]676<p>Note that the "<tt><a href="#cl::list">cl::list</a></tt>" template is
677completely general and may be used with any data types or other arguments that
678you can use with the "<tt><a href="#cl::opt">cl::opt</a></tt>" template. One
679especially useful way to use a list is to capture all of the positional
680arguments together if there may be more than one specified. In the case of a
681linker, for example, the linker takes several '<tt>.o</tt>' files, and needs to
682capture them into a list. This is naturally specified as:</p>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]683
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]684<div class="doc_code"><pre>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]685...
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]686<a href="#cl::list">cl::list</a>&lt;std::string&gt; InputFilenames(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("&lt;Input files&gt;"), <a href="#cl::OneOrMore">cl::OneOrMore</a>);
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]687...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]688</pre></div>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]689
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]690<p>This variable works just like a "<tt>vector&lt;string&gt;</tt>" object. As
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]691such, accessing the list is simple, just like above. In this example, we used
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]692the <tt><a href="#cl::OneOrMore">cl::OneOrMore</a></tt> modifier to inform the
693CommandLine library that it is an error if the user does not specify any
694<tt>.o</tt> files on our command line. Again, this just reduces the amount of
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]695checking we have to do.</p>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]696
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]697</div>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]698
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]699<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]700<h3>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]701 <a name="bits">Collecting options as a set of flags</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]702</h3>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]703
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]704<div>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]705
706<p>Instead of collecting sets of options in a list, it is also possible to
Dan Gohman42f56912010-02-26 20:18:32 +0000[diff] [blame]707gather information for enum values in a <b>bit vector</b>. The representation used by
Jim Laskeyd6281ce2005-08-26 09:25:54 +0000[diff] [blame]708the <a href="#bits"><tt>cl::bits</tt></a> class is an <tt>unsigned</tt>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]709integer. An enum value is represented by a 0/1 in the enum's ordinal value bit
710position. 1 indicating that the enum was specified, 0 otherwise. As each
711specified value is parsed, the resulting enum's bit is set in the option's bit
712vector:</p>
713
714<div class="doc_code"><pre>
715 <i>bits</i> |= 1 << (unsigned)<i>enum</i>;
716</pre></div>
717
Jim Laskeya82d08f2005-08-25 23:01:25 +0000[diff] [blame]718<p>Options that are specified multiple times are redundant. Any instances after
719the first are discarded.</p>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]720
721<p>Reworking the above list example, we could replace <a href="#list">
722<tt>cl::list</tt></a> with <a href="#bits"><tt>cl::bits</tt></a>:</p>
723
724<div class="doc_code"><pre>
725<a href="#cl::bits">cl::bits</a>&lt;Opts&gt; OptimizationBits(<a href="#cl::desc">cl::desc</a>("<i>Available Optimizations:</i>"),
726 <a href="#cl::values">cl::values</a>(
727 clEnumVal(dce , "<i>Dead Code Elimination</i>"),
728 clEnumVal(constprop , "<i>Constant Propagation</i>"),
729 clEnumValN(inlining, "<i>inline</i>", "<i>Procedure Integration</i>"),
730 clEnumVal(strip , "<i>Strip Symbols</i>"),
731 clEnumValEnd));
732</pre></div>
733
734<p>To test to see if <tt>constprop</tt> was specified, we can use the
735<tt>cl:bits::isSet</tt> function:</p>
736
737<div class="doc_code"><pre>
738 if (OptimizationBits.isSet(constprop)) {
739 ...
740 }
741</pre></div>
742
743<p>It's also possible to get the raw bit vector using the
744<tt>cl::bits::getBits</tt> function:</p>
745
746<div class="doc_code"><pre>
Jim Laskeyd6281ce2005-08-26 09:25:54 +0000[diff] [blame]747 unsigned bits = OptimizationBits.getBits();
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]748</pre></div>
749
750<p>Finally, if external storage is used, then the location specified must be of
Jim Laskeyd6281ce2005-08-26 09:25:54 +0000[diff] [blame]751<b>type</b> <tt>unsigned</tt>. In all other ways a <a
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]752href="#bits"><tt>cl::bits</tt></a> option is equivalent to a <a
Jim Laskeyd6281ce2005-08-26 09:25:54 +0000[diff] [blame]753href="#list"> <tt>cl::list</tt></a> option.</p>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]754
755</div>
756
757
758<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]759<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]760 <a name="description">Adding freeform text to help output</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]761</h3>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]762
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]763<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]764
765<p>As our program grows and becomes more mature, we may decide to put summary
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]766information about what it does into the help output. The help output is styled
767to look similar to a Unix <tt>man</tt> page, providing concise information about
768a program. Unix <tt>man</tt> pages, however often have a description about what
769the program does. To add this to your CommandLine program, simply pass a third
770argument to the <a
771href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>
772call in main. This additional argument is then printed as the overview
773information for your program, allowing you to include any additional information
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]774that you want. For example:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]775
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]776<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]777int main(int argc, char **argv) {
778 <a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv, " CommandLine compiler example\n\n"
779 " This program blah blah blah...\n");
780 ...
781}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]782</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]783
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]784<p>would yield the help output:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]785
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]786<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]787<b>OVERVIEW: CommandLine compiler example
788
789 This program blah blah blah...</b>
790
791USAGE: compiler [options] &lt;input file&gt;
792
793OPTIONS:
794 ...
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]795 -help - display available options (-help-hidden for more)
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]796 -o &lt;filename&gt; - Specify output filename
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]797</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]798
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]799</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]800
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]801</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]802
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]803<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]804<h2>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]805 <a name="referenceguide">Reference Guide</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]806</h2>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]807<!-- *********************************************************************** -->
808
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]809<div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]810
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]811<p>Now that you know the basics of how to use the CommandLine library, this
812section will give you the detailed information you need to tune how command line
813options work, as well as information on more "advanced" command line option
814processing capabilities.</p>
815
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]816<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]817<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]818 <a name="positional">Positional Arguments</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]819</h3>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]820
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]821<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]822
823<p>Positional arguments are those arguments that are not named, and are not
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]824specified with a hyphen. Positional arguments should be used when an option is
825specified by its position alone. For example, the standard Unix <tt>grep</tt>
826tool takes a regular expression argument, and an optional filename to search
827through (which defaults to standard input if a filename is not specified).
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]828Using the CommandLine library, this would be specified as:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]829
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]830<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]831<a href="#cl::opt">cl::opt</a>&lt;string&gt; Regex (<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;regular expression&gt;</i>"), <a href="#cl::Required">cl::Required</a>);
832<a href="#cl::opt">cl::opt</a>&lt;string&gt; Filename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <a href="#cl::init">cl::init</a>("<i>-</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]833</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]834
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]835<p>Given these two option declarations, the <tt>-help</tt> output for our grep
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]836replacement would look like this:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]837
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]838<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]839USAGE: spiffygrep [options] <b>&lt;regular expression&gt; &lt;input file&gt;</b>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]840
841OPTIONS:
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]842 -help - display available options (-help-hidden for more)
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]843</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]844
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]845<p>... and the resultant program could be used just like the standard
846<tt>grep</tt> tool.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]847
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]848<p>Positional arguments are sorted by their order of construction. This means
849that command line options will be ordered according to how they are listed in a
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]850.cpp file, but will not have an ordering defined if the positional arguments
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]851are defined in multiple .cpp files. The fix for this problem is simply to
852define all of your positional arguments in one .cpp file.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]853
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]854<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]855<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]856 <a name="--">Specifying positional options with hyphens</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]857</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]858
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]859<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]860
861<p>Sometimes you may want to specify a value to your positional argument that
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]862starts with a hyphen (for example, searching for '<tt>-foo</tt>' in a file). At
863first, you will have trouble doing this, because it will try to find an argument
864named '<tt>-foo</tt>', and will fail (and single quotes will not save you).
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]865Note that the system <tt>grep</tt> has the same problem:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]866
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]867<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]868 $ spiffygrep '-foo' test.txt
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]869 Unknown command line argument '-foo'. Try: spiffygrep -help'
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]870
871 $ grep '-foo' test.txt
872 grep: illegal option -- f
873 grep: illegal option -- o
874 grep: illegal option -- o
875 Usage: grep -hblcnsviw pattern file . . .
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]876</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]877
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]878<p>The solution for this problem is the same for both your tool and the system
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]879version: use the '<tt>--</tt>' marker. When the user specifies '<tt>--</tt>' on
880the command line, it is telling the program that all options after the
881'<tt>--</tt>' should be treated as positional arguments, not options. Thus, we
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]882can use it like this:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]883
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]884<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]885 $ spiffygrep -- -foo test.txt
886 ...output...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]887</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]888
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]889</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]890
891<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]892<h4>
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]893 <a name="getPosition">Determining absolute position with getPosition()</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]894</h4>
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]895<div>
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]896 <p>Sometimes an option can affect or modify the meaning of another option. For
897 example, consider <tt>gcc</tt>'s <tt>-x LANG</tt> option. This tells
898 <tt>gcc</tt> to ignore the suffix of subsequent positional arguments and force
899 the file to be interpreted as if it contained source code in language
Chris Lattner5db870c2008-04-01 18:02:36 +0000[diff] [blame]900 <tt>LANG</tt>. In order to handle this properly, you need to know the
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]901 absolute position of each argument, especially those in lists, so their
902 interaction(s) can be applied correctly. This is also useful for options like
903 <tt>-llibname</tt> which is actually a positional argument that starts with
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]904 a dash.</p>
905 <p>So, generally, the problem is that you have two <tt>cl::list</tt> variables
906 that interact in some way. To ensure the correct interaction, you can use the
907 <tt>cl::list::getPosition(optnum)</tt> method. This method returns the
908 absolute position (as found on the command line) of the <tt>optnum</tt>
909 item in the <tt>cl::list</tt>.</p>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]910 <p>The idiom for usage is like this:</p>
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]911
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]912 <div class="doc_code"><pre>
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]913 static cl::list&lt;std::string&gt; Files(cl::Positional, cl::OneOrMore);
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]914 static cl::list&lt;std::string&gt; Libraries("l", cl::ZeroOrMore);
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]915
916 int main(int argc, char**argv) {
917 // ...
918 std::vector&lt;std::string&gt;::iterator fileIt = Files.begin();
919 std::vector&lt;std::string&gt;::iterator libIt = Libraries.begin();
920 unsigned libPos = 0, filePos = 0;
921 while ( 1 ) {
922 if ( libIt != Libraries.end() )
923 libPos = Libraries.getPosition( libIt - Libraries.begin() );
924 else
925 libPos = 0;
926 if ( fileIt != Files.end() )
927 filePos = Files.getPosition( fileIt - Files.begin() );
928 else
929 filePos = 0;
930
931 if ( filePos != 0 &amp;&amp; (libPos == 0 || filePos &lt; libPos) ) {
932 // Source File Is next
933 ++fileIt;
934 }
935 else if ( libPos != 0 &amp;&amp; (filePos == 0 || libPos &lt; filePos) ) {
936 // Library is next
937 ++libIt;
938 }
939 else
940 break; // we're done with the list
941 }
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]942 }</pre></div>
943
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]944 <p>Note that, for compatibility reasons, the <tt>cl::opt</tt> also supports an
945 <tt>unsigned getPosition()</tt> option that will provide the absolute position
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]946 of that option. You can apply the same approach as above with a
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]947 <tt>cl::opt</tt> and a <tt>cl::list</tt> option as you can with two lists.</p>
948</div>
949
950<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]951<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]952 <a name="cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt> modifier</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]953</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]954
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]955<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]956
957<p>The <tt>cl::ConsumeAfter</tt> <a href="#formatting">formatting option</a> is
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]958used to construct programs that use "interpreter style" option processing. With
959this style of option processing, all arguments specified after the last
960positional argument are treated as special interpreter arguments that are not
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]961interpreted by the command line argument.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]962
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]963<p>As a concrete example, lets say we are developing a replacement for the
964standard Unix Bourne shell (<tt>/bin/sh</tt>). To run <tt>/bin/sh</tt>, first
965you specify options to the shell itself (like <tt>-x</tt> which turns on trace
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]966output), then you specify the name of the script to run, then you specify
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]967arguments to the script. These arguments to the script are parsed by the Bourne
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]968shell command line option processor, but are not interpreted as options to the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]969shell itself. Using the CommandLine library, we would specify this as:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]970
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]971<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]972<a href="#cl::opt">cl::opt</a>&lt;string&gt; Script(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input script&gt;</i>"), <a href="#cl::init">cl::init</a>("-"));
973<a href="#cl::list">cl::list</a>&lt;string&gt; Argv(<a href="#cl::ConsumeAfter">cl::ConsumeAfter</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;program arguments&gt;...</i>"));
974<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Trace("<i>x</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable trace output</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]975</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]976
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]977<p>which automatically provides the help output:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]978
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]979<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]980USAGE: spiffysh [options] <b>&lt;input script&gt; &lt;program arguments&gt;...</b>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]981
982OPTIONS:
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]983 -help - display available options (-help-hidden for more)
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]984 <b>-x - Enable trace output</b>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]985</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]986
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]987<p>At runtime, if we run our new shell replacement as `<tt>spiffysh -x test.sh
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]988-a -x -y bar</tt>', the <tt>Trace</tt> variable will be set to true, the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]989<tt>Script</tt> variable will be set to "<tt>test.sh</tt>", and the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]990<tt>Argv</tt> list will contain <tt>["-a", "-x", "-y", "bar"]</tt>, because they
991were specified after the last positional argument (which is the script
992name).</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]993
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]994<p>There are several limitations to when <tt>cl::ConsumeAfter</tt> options can
995be specified. For example, only one <tt>cl::ConsumeAfter</tt> can be specified
996per program, there must be at least one <a href="#positional">positional
Chris Lattnerb68bd762004-05-06 22:03:59 +0000[diff] [blame]997argument</a> specified, there must not be any <a href="#cl::list">cl::list</a>
998positional arguments, and the <tt>cl::ConsumeAfter</tt> option should be a <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]999href="#cl::list">cl::list</a> option.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1000
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1001</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1002
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1003</div>
1004
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1005<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1006<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1007 <a name="storage">Internal vs External Storage</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1008</h3>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1009
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1010<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1011
1012<p>By default, all command line options automatically hold the value that they
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1013parse from the command line. This is very convenient in the common case,
1014especially when combined with the ability to define command line options in the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1015files that use them. This is called the internal storage model.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1016
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1017<p>Sometimes, however, it is nice to separate the command line option processing
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1018code from the storage of the value parsed. For example, lets say that we have a
1019'<tt>-debug</tt>' option that we would like to use to enable debug information
1020across the entire body of our program. In this case, the boolean value
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]1021controlling the debug code should be globally accessible (in a header file, for
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1022example) yet the command line option processing code should not be exposed to
1023all of these clients (requiring lots of .cpp files to #include
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1024<tt>CommandLine.h</tt>).</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1025
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1026<p>To do this, set up your .h file with your option, like this for example:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1027
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1028<div class="doc_code">
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1029<pre>
1030<i>// DebugFlag.h - Get access to the '-debug' command line option
1031//
1032
1033// DebugFlag - This boolean is set to true if the '-debug' command line option
1034// is specified. This should probably not be referenced directly, instead, use
1035// the DEBUG macro below.
1036//</i>
1037extern bool DebugFlag;
1038
1039<i>// DEBUG macro - This macro should be used by code to emit debug information.
1040// In the '-debug' option is specified on the command line, and if this is a
1041// debug build, then the code specified as the option to the macro will be
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1042// executed. Otherwise it will not be.</i>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1043<span class="doc_hilite">#ifdef NDEBUG
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1044#define DEBUG(X)
1045#else
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1046#define DEBUG(X)</span> do { if (DebugFlag) { X; } } while (0)
1047<span class="doc_hilite">#endif</span>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1048</pre>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1049</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1050
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1051<p>This allows clients to blissfully use the <tt>DEBUG()</tt> macro, or the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1052<tt>DebugFlag</tt> explicitly if they want to. Now we just need to be able to
1053set the <tt>DebugFlag</tt> boolean when the option is set. To do this, we pass
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1054an additional argument to our command line argument processor, and we specify
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1055where to fill in with the <a href="#cl::location">cl::location</a>
1056attribute:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1057
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1058<div class="doc_code">
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1059<pre>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1060bool DebugFlag; <i>// the actual value</i>
Chris Lattner76884682003-08-01 21:30:37 +0000[diff] [blame]1061static <a href="#cl::opt">cl::opt</a>&lt;bool, true&gt; <i>// The parser</i>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1062Debug("<i>debug</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable debug output</i>"), <a href="#cl::Hidden">cl::Hidden</a>, <a href="#cl::location">cl::location</a>(DebugFlag));
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1063</pre>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1064</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1065
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1066<p>In the above example, we specify "<tt>true</tt>" as the second argument to
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1067the <tt><a href="#cl::opt">cl::opt</a></tt> template, indicating that the
1068template should not maintain a copy of the value itself. In addition to this,
1069we specify the <tt><a href="#cl::location">cl::location</a></tt> attribute, so
1070that <tt>DebugFlag</tt> is automatically set.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1071
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1072</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1073
1074<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1075<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1076 <a name="attributes">Option Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1077</h3>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1078
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1079<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1080
1081<p>This section describes the basic attributes that you can specify on
1082options.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1083
1084<ul>
1085
1086<li>The option name attribute (which is required for all options, except <a
1087href="#positional">positional options</a>) specifies what the option name is.
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1088This option is specified in simple double quotes:
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1089
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1090<pre>
1091<a href="#cl::opt">cl::opt</a>&lt;<b>bool</b>&gt; Quiet("<i>quiet</i>");
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1092</pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1093
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1094</li>
1095
1096<li><a name="cl::desc">The <b><tt>cl::desc</tt></b></a> attribute specifies a
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1097description for the option to be shown in the <tt>-help</tt> output for the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1098program.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1099
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1100<li><a name="cl::value_desc">The <b><tt>cl::value_desc</tt></b></a> attribute
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1101specifies a string that can be used to fine tune the <tt>-help</tt> output for
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1102a command line option. Look <a href="#value_desc_example">here</a> for an
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1103example.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1104
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1105<li><a name="cl::init">The <b><tt>cl::init</tt></b></a> attribute specifies an
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]1106initial value for a <a href="#cl::opt">scalar</a> option. If this attribute is
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1107not specified then the command line option value defaults to the value created
Brian Gaeke8b89b2b2003-08-19 22:56:22 +0000[diff] [blame]1108by the default constructor for the type. <b>Warning</b>: If you specify both
1109<b><tt>cl::init</tt></b> and <b><tt>cl::location</tt></b> for an option,
1110you must specify <b><tt>cl::location</tt></b> first, so that when the
1111command-line parser sees <b><tt>cl::init</tt></b>, it knows where to put the
1112initial value. (You will get an error at runtime if you don't put them in
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1113the right order.)</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1114
Mikhail Glushenkov132a4712009-06-17 03:09:39 +0000[diff] [blame]1115<li><a name="cl::location">The <b><tt>cl::location</tt></b></a> attribute where
1116to store the value for a parsed command line option if using external storage.
1117See the section on <a href="#storage">Internal vs External Storage</a> for more
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1118information.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1119
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1120<li><a name="cl::aliasopt">The <b><tt>cl::aliasopt</tt></b></a> attribute
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1121specifies which option a <tt><a href="#cl::alias">cl::alias</a></tt> option is
1122an alias for.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1123
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1124<li><a name="cl::values">The <b><tt>cl::values</tt></b></a> attribute specifies
1125the string-to-value mapping to be used by the generic parser. It takes a
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]1126<b>clEnumValEnd terminated</b> list of (option, value, description) triplets
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]1127that
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1128specify the option name, the value mapped to, and the description shown in the
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1129<tt>-help</tt> for the tool. Because the generic parser is used most
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1130frequently with enum values, two macros are often useful:
1131
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1132<ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1133
1134<li><a name="clEnumVal">The <b><tt>clEnumVal</tt></b></a> macro is used as a
1135nice simple way to specify a triplet for an enum. This macro automatically
1136makes the option name be the same as the enum name. The first option to the
1137macro is the enum, the second is the description for the command line
1138option.</li>
1139
1140<li><a name="clEnumValN">The <b><tt>clEnumValN</tt></b></a> macro is used to
1141specify macro options where the option name doesn't equal the enum name. For
1142this macro, the first argument is the enum value, the second is the flag name,
1143and the second is the description.</li>
1144
Mikhail Glushenkov132a4712009-06-17 03:09:39 +0000[diff] [blame]1145</ol>
1146
1147You will get a compile time error if you try to use cl::values with a parser
1148that does not support it.</li>
1149
Mikhail Glushenkovcbc26fd2009-01-16 22:54:19 +0000[diff] [blame]1150<li><a name="cl::multi_val">The <b><tt>cl::multi_val</tt></b></a>
1151attribute specifies that this option takes has multiple values
1152(example: <tt>-sectalign segname sectname sectvalue</tt>). This
1153attribute takes one unsigned argument - the number of values for the
1154option. This attribute is valid only on <tt>cl::list</tt> options (and
1155will fail with compile error if you try to use it with other option
1156types). It is allowed to use all of the usual modifiers on
1157multi-valued options (besides <tt>cl::ValueDisallowed</tt>,
1158obviously).</li>
1159
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1160</ul>
1161
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1162</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1163
1164<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1165<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1166 <a name="modifiers">Option Modifiers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1167</h3>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1168
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1169<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1170
1171<p>Option modifiers are the flags and expressions that you pass into the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1172constructors for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
1173href="#cl::list">cl::list</a></tt>. These modifiers give you the ability to
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1174tweak how options are parsed and how <tt>-help</tt> output is generated to fit
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1175your application well.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1176
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]1177<p>These options fall into five main categories:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1178
1179<ol>
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1180<li><a href="#hiding">Hiding an option from <tt>-help</tt> output</a></li>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1181<li><a href="#numoccurrences">Controlling the number of occurrences
1182 required and allowed</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1183<li><a href="#valrequired">Controlling whether or not a value must be
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1184 specified</a></li>
1185<li><a href="#formatting">Controlling other formatting options</a></li>
1186<li><a href="#misc">Miscellaneous option modifiers</a></li>
1187</ol>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1188
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]1189<p>It is not possible to specify two options from the same category (you'll get
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1190a runtime error) to a single option, except for options in the miscellaneous
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]1191category. The CommandLine library specifies defaults for all of these settings
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1192that are the most useful in practice and the most common, which mean that you
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1193usually shouldn't have to worry about these.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1194
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1195<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1196<h4>
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1197 <a name="hiding">Hiding an option from <tt>-help</tt> output</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1198</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1199
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1200<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1201
1202<p>The <tt>cl::NotHidden</tt>, <tt>cl::Hidden</tt>, and
1203<tt>cl::ReallyHidden</tt> modifiers are used to control whether or not an option
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1204appears in the <tt>-help</tt> and <tt>-help-hidden</tt> output for the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1205compiled program:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1206
1207<ul>
1208
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1209<li><a name="cl::NotHidden">The <b><tt>cl::NotHidden</tt></b></a> modifier
1210(which is the default for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1211href="#cl::list">cl::list</a></tt> options) indicates the option is to appear
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1212in both help listings.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1213
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1214<li><a name="cl::Hidden">The <b><tt>cl::Hidden</tt></b></a> modifier (which is the
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1215default for <tt><a href="#cl::alias">cl::alias</a></tt> options) indicates that
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1216the option should not appear in the <tt>-help</tt> output, but should appear in
1217the <tt>-help-hidden</tt> output.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1218
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1219<li><a name="cl::ReallyHidden">The <b><tt>cl::ReallyHidden</tt></b></a> modifier
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1220indicates that the option should not appear in any help output.</li>
1221
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1222</ul>
1223
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1224</div>
1225
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1226<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1227<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1228 <a name="numoccurrences">Controlling the number of occurrences required and
1229 allowed</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1230</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1231
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1232<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1233
1234<p>This group of options is used to control how many time an option is allowed
1235(or required) to be specified on the command line of your program. Specifying a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1236value for this setting allows the CommandLine library to do error checking for
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1237you.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1238
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1239<p>The allowed values for this option group are:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1240
1241<ul>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1242
1243<li><a name="cl::Optional">The <b><tt>cl::Optional</tt></b></a> modifier (which
1244is the default for the <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1245href="#cl::alias">cl::alias</a></tt> classes) indicates that your program will
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1246allow either zero or one occurrence of the option to be specified.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1247
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1248<li><a name="cl::ZeroOrMore">The <b><tt>cl::ZeroOrMore</tt></b></a> modifier
1249(which is the default for the <tt><a href="#cl::list">cl::list</a></tt> class)
1250indicates that your program will allow the option to be specified zero or more
1251times.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1252
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1253<li><a name="cl::Required">The <b><tt>cl::Required</tt></b></a> modifier
1254indicates that the specified option must be specified exactly one time.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1255
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1256<li><a name="cl::OneOrMore">The <b><tt>cl::OneOrMore</tt></b></a> modifier
1257indicates that the option must be specified at least one time.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1258
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1259<li>The <b><tt>cl::ConsumeAfter</tt></b> modifier is described in the <a
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1260href="#positional">Positional arguments section</a>.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1261
1262</ul>
1263
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1264<p>If an option is not specified, then the value of the option is equal to the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1265value specified by the <tt><a href="#cl::init">cl::init</a></tt> attribute. If
1266the <tt><a href="#cl::init">cl::init</a></tt> attribute is not specified, the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1267option value is initialized with the default constructor for the data type.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1268
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1269<p>If an option is specified multiple times for an option of the <tt><a
1270href="#cl::opt">cl::opt</a></tt> class, only the last value will be
1271retained.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1272
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1273</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1274
1275<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1276<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1277 <a name="valrequired">Controlling whether or not a value must be specified</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1278</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1279
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1280<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1281
1282<p>This group of options is used to control whether or not the option allows a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1283value to be present. In the case of the CommandLine library, a value is either
1284specified with an equal sign (e.g. '<tt>-index-depth=17</tt>') or as a trailing
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1285string (e.g. '<tt>-o a.out</tt>').</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1286
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1287<p>The allowed values for this option group are:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1288
1289<ul>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1290
1291<li><a name="cl::ValueOptional">The <b><tt>cl::ValueOptional</tt></b></a> modifier
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1292(which is the default for <tt>bool</tt> typed options) specifies that it is
1293acceptable to have a value, or not. A boolean argument can be enabled just by
1294appearing on the command line, or it can have an explicit '<tt>-foo=true</tt>'.
1295If an option is specified with this mode, it is illegal for the value to be
1296provided without the equal sign. Therefore '<tt>-foo true</tt>' is illegal. To
1297get this behavior, you must use the <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1298href="#cl::ValueRequired">cl::ValueRequired</a> modifier.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1299
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1300<li><a name="cl::ValueRequired">The <b><tt>cl::ValueRequired</tt></b></a> modifier
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1301(which is the default for all other types except for <a
1302href="#onealternative">unnamed alternatives using the generic parser</a>)
1303specifies that a value must be provided. This mode informs the command line
1304library that if an option is not provides with an equal sign, that the next
1305argument provided must be the value. This allows things like '<tt>-o
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1306a.out</tt>' to work.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1307
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1308<li><a name="cl::ValueDisallowed">The <b><tt>cl::ValueDisallowed</tt></b></a>
1309modifier (which is the default for <a href="#onealternative">unnamed
1310alternatives using the generic parser</a>) indicates that it is a runtime error
1311for the user to specify a value. This can be provided to disallow users from
1312providing options to boolean options (like '<tt>-foo=true</tt>').</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1313
1314</ul>
1315
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1316<p>In general, the default values for this option group work just like you would
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1317want them to. As mentioned above, you can specify the <a
1318href="#cl::ValueDisallowed">cl::ValueDisallowed</a> modifier to a boolean
1319argument to restrict your command line parser. These options are mostly useful
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1320when <a href="#extensionguide">extending the library</a>.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1321
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1322</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1323
1324<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1325<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1326 <a name="formatting">Controlling other formatting options</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1327</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1328
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1329<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1330
1331<p>The formatting option group is used to specify that the command line option
1332has special abilities and is otherwise different from other command line
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1333arguments. As usual, you can only specify one of these arguments at most.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1334
1335<ul>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1336
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1337<li><a name="cl::NormalFormatting">The <b><tt>cl::NormalFormatting</tt></b></a>
1338modifier (which is the default all options) specifies that this option is
1339"normal".</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1340
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1341<li><a name="cl::Positional">The <b><tt>cl::Positional</tt></b></a> modifier
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1342specifies that this is a positional argument that does not have a command line
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1343option associated with it. See the <a href="#positional">Positional
1344Arguments</a> section for more information.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1345
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1346<li>The <b><a href="#cl::ConsumeAfter"><tt>cl::ConsumeAfter</tt></a></b> modifier
1347specifies that this option is used to capture "interpreter style" arguments. See <a href="#cl::ConsumeAfter">this section for more information</a>.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1348
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1349<li><a name="cl::Prefix">The <b><tt>cl::Prefix</tt></b></a> modifier specifies
Reid Spencer80bb6932004-11-24 06:13:42 +0000[diff] [blame]1350that this option prefixes its value. With 'Prefix' options, the equal sign does
1351not separate the value from the option name specified. Instead, the value is
1352everything after the prefix, including any equal sign if present. This is useful
1353for processing odd arguments like <tt>-lmalloc</tt> and <tt>-L/usr/lib</tt> in a
Misha Brukman3f2fa8d2005-05-10 22:05:27 +0000[diff] [blame]1354linker tool or <tt>-DNAME=value</tt> in a compiler tool. Here, the
Reid Spencer80bb6932004-11-24 06:13:42 +0000[diff] [blame]1355'<tt>l</tt>', '<tt>D</tt>' and '<tt>L</tt>' options are normal string (or list)
Misha Brukman3f2fa8d2005-05-10 22:05:27 +0000[diff] [blame]1356options, that have the <b><tt><a href="#cl::Prefix">cl::Prefix</a></tt></b>
1357modifier added to allow the CommandLine library to recognize them. Note that
1358<b><tt><a href="#cl::Prefix">cl::Prefix</a></tt></b> options must not have the
1359<b><tt><a href="#cl::ValueDisallowed">cl::ValueDisallowed</a></tt></b> modifier
1360specified.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1361
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1362<li><a name="cl::Grouping">The <b><tt>cl::Grouping</tt></b></a> modifier is used
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1363to implement Unix-style tools (like <tt>ls</tt>) that have lots of single letter
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1364arguments, but only require a single dash. For example, the '<tt>ls -labF</tt>'
1365command actually enables four different options, all of which are single
Misha Brukman3f2fa8d2005-05-10 22:05:27 +0000[diff] [blame]1366letters. Note that <b><tt><a href="#cl::Grouping">cl::Grouping</a></tt></b>
1367options cannot have values.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1368
1369</ul>
1370
Misha Brukman3f2fa8d2005-05-10 22:05:27 +0000[diff] [blame]1371<p>The CommandLine library does not restrict how you use the <b><tt><a
1372href="#cl::Prefix">cl::Prefix</a></tt></b> or <b><tt><a
1373href="#cl::Grouping">cl::Grouping</a></tt></b> modifiers, but it is possible to
1374specify ambiguous argument settings. Thus, it is possible to have multiple
1375letter options that are prefix or grouping options, and they will still work as
1376designed.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1377
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1378<p>To do this, the CommandLine library uses a greedy algorithm to parse the
1379input option into (potentially multiple) prefix and grouping options. The
1380strategy basically looks like this:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1381
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1382<div class="doc_code"><tt>parse(string OrigInput) {</tt>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1383
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1384<ol>
1385<li><tt>string input = OrigInput;</tt>
1386<li><tt>if (isOption(input)) return getOption(input).parse();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// Normal option</i>
1387<li><tt>while (!isOption(input) &amp;&amp; !input.empty()) input.pop_back();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// Remove the last letter</i>
1388<li><tt>if (input.empty()) return error();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// No matching option</i>
1389<li><tt>if (getOption(input).isPrefix())<br>
1390&nbsp;&nbsp;return getOption(input).parse(input);</tt>
1391<li><tt>while (!input.empty()) {&nbsp;&nbsp;&nbsp;&nbsp;<i>// Must be grouping options</i><br>
1392&nbsp;&nbsp;getOption(input).parse();<br>
1393&nbsp;&nbsp;OrigInput.erase(OrigInput.begin(), OrigInput.begin()+input.length());<br>
1394&nbsp;&nbsp;input = OrigInput;<br>
1395&nbsp;&nbsp;while (!isOption(input) &amp;&amp; !input.empty()) input.pop_back();<br>
1396}</tt>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1397<li><tt>if (!OrigInput.empty()) error();</tt></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1398</ol>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1399
1400<p><tt>}</tt></p>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1401</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1402
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1403</div>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1404
1405<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1406<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1407 <a name="misc">Miscellaneous option modifiers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1408</h4>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1409
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1410<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1411
1412<p>The miscellaneous option modifiers are the only flags where you can specify
1413more than one flag from the set: they are not mutually exclusive. These flags
1414specify boolean properties that modify the option.</p>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1415
1416<ul>
1417
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1418<li><a name="cl::CommaSeparated">The <b><tt>cl::CommaSeparated</tt></b></a> modifier
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1419indicates that any commas specified for an option's value should be used to
1420split the value up into multiple values for the option. For example, these two
1421options are equivalent when <tt>cl::CommaSeparated</tt> is specified:
1422"<tt>-foo=a -foo=b -foo=c</tt>" and "<tt>-foo=a,b,c</tt>". This option only
1423makes sense to be used in a case where the option is allowed to accept one or
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1424more values (i.e. it is a <a href="#cl::list">cl::list</a> option).</li>
1425
Chris Lattnerb68bd762004-05-06 22:03:59 +0000[diff] [blame]1426<li><a name="cl::PositionalEatsArgs">The
1427<b><tt>cl::PositionalEatsArgs</tt></b></a> modifier (which only applies to
1428positional arguments, and only makes sense for lists) indicates that positional
1429argument should consume any strings after it (including strings that start with
1430a "-") up until another recognized positional argument. For example, if you
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1431have two "eating" positional arguments, "<tt>pos1</tt>" and "<tt>pos2</tt>", the
Chris Lattnerb68bd762004-05-06 22:03:59 +0000[diff] [blame]1432string "<tt>-pos1 -foo -bar baz -pos2 -bork</tt>" would cause the "<tt>-foo -bar
1433-baz</tt>" strings to be applied to the "<tt>-pos1</tt>" option and the
1434"<tt>-bork</tt>" string to be applied to the "<tt>-pos2</tt>" option.</li>
1435
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]1436<li><a name="cl::Sink">The <b><tt>cl::Sink</tt></b></a> modifier is
1437used to handle unknown options. If there is at least one option with
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]1438<tt>cl::Sink</tt> modifier specified, the parser passes
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]1439unrecognized option strings to it as values instead of signaling an
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]1440error. As with <tt>cl::CommaSeparated</tt>, this modifier
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]1441only makes sense with a <a href="#cl::list">cl::list</a> option.</li>
1442
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1443</ul>
1444
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]1445<p>So far, these are the only three miscellaneous option modifiers.</p>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1446
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1447</div>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1448
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1449<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1450<h4>
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1451 <a name="response">Response files</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1452</h4>
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1453
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1454<div>
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1455
1456<p>Some systems, such as certain variants of Microsoft Windows and
1457some older Unices have a relatively low limit on command-line
1458length. It is therefore customary to use the so-called 'response
1459files' to circumvent this restriction. These files are mentioned on
1460the command-line (using the "@file") syntax. The program reads these
1461files and inserts the contents into argv, thereby working around the
1462command-line length limits. Response files are enabled by an optional
1463fourth argument to
1464<a href="#cl::ParseEnvironmentOptions"><tt>cl::ParseEnvironmentOptions</tt></a>
1465and
1466<a href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>.
1467</p>
1468
1469</div>
1470
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1471</div>
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1472
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1473<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1474<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1475 <a name="toplevel">Top-Level Classes and Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1476</h3>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1477
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1478<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1479
1480<p>Despite all of the built-in flexibility, the CommandLine option library
1481really only consists of one function (<a
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1482href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>)
1483and three main classes: <a href="#cl::opt"><tt>cl::opt</tt></a>, <a
1484href="#cl::list"><tt>cl::list</tt></a>, and <a
1485href="#cl::alias"><tt>cl::alias</tt></a>. This section describes these three
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1486classes in detail.</p>
1487
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1488<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1489<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1490 <a name="cl::ParseCommandLineOptions">The <tt>cl::ParseCommandLineOptions</tt>
1491 function</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1492</h4>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1493
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1494<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1495
1496<p>The <tt>cl::ParseCommandLineOptions</tt> function is designed to be called
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1497directly from <tt>main</tt>, and is used to fill in the values of all of the
1498command line option variables once <tt>argc</tt> and <tt>argv</tt> are
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1499available.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1500
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1501<p>The <tt>cl::ParseCommandLineOptions</tt> function requires two parameters
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1502(<tt>argc</tt> and <tt>argv</tt>), but may also take an optional third parameter
1503which holds <a href="#description">additional extra text</a> to emit when the
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1504<tt>-help</tt> option is invoked, and a fourth boolean parameter that enables
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1505<a href="#response">response files</a>.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1506
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1507</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1508
1509<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1510<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1511 <a name="cl::ParseEnvironmentOptions">The <tt>cl::ParseEnvironmentOptions</tt>
1512 function</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1513</h4>
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1514
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1515<div>
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1516
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1517<p>The <tt>cl::ParseEnvironmentOptions</tt> function has mostly the same effects
1518as <a
1519href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>,
1520except that it is designed to take values for options from an environment
1521variable, for those cases in which reading the command line is not convenient or
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1522desired. It fills in the values of all the command line option variables just
1523like <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1524href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>
1525does.</p>
1526
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1527<p>It takes four parameters: the name of the program (since <tt>argv</tt> may
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1528not be available, it can't just look in <tt>argv[0]</tt>), the name of the
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1529environment variable to examine, the optional
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1530<a href="#description">additional extra text</a> to emit when the
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1531<tt>-help</tt> option is invoked, and the boolean
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]1532switch that controls whether <a href="#response">response files</a>
Mikhail Glushenkov5653d3b2008-04-28 16:44:25 +0000[diff] [blame]1533should be read.</p>
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1534
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1535<p><tt>cl::ParseEnvironmentOptions</tt> will break the environment
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1536variable's value up into words and then process them using
1537<a href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>.
1538<b>Note:</b> Currently <tt>cl::ParseEnvironmentOptions</tt> does not support
1539quoting, so an environment variable containing <tt>-option "foo bar"</tt> will
1540be parsed as three words, <tt>-option</tt>, <tt>"foo</tt>, and <tt>bar"</tt>,
1541which is different from what you would get from the shell with the same
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1542input.</p>
1543
1544</div>
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1545
1546<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1547<h4>
Reid Spencer0075b2f2006-06-05 17:30:16 +0000[diff] [blame]1548 <a name="cl::SetVersionPrinter">The <tt>cl::SetVersionPrinter</tt>
1549 function</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1550</h4>
Reid Spencer0075b2f2006-06-05 17:30:16 +0000[diff] [blame]1551
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1552<div>
Reid Spencer0075b2f2006-06-05 17:30:16 +0000[diff] [blame]1553
1554<p>The <tt>cl::SetVersionPrinter</tt> function is designed to be called
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1555directly from <tt>main</tt> and <i>before</i>
Reid Spencer0075b2f2006-06-05 17:30:16 +0000[diff] [blame]1556<tt>cl::ParseCommandLineOptions</tt>. Its use is optional. It simply arranges
1557for a function to be called in response to the <tt>--version</tt> option instead
1558of having the <tt>CommandLine</tt> library print out the usual version string
1559for LLVM. This is useful for programs that are not part of LLVM but wish to use
1560the <tt>CommandLine</tt> facilities. Such programs should just define a small
1561function that takes no arguments and returns <tt>void</tt> and that prints out
1562whatever version information is appropriate for the program. Pass the address
1563of that function to <tt>cl::SetVersionPrinter</tt> to arrange for it to be
1564called when the <tt>--version</tt> option is given by the user.</p>
1565
1566</div>
1567<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1568<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1569 <a name="cl::opt">The <tt>cl::opt</tt> class</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1570</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1571
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1572<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1573
1574<p>The <tt>cl::opt</tt> class is the class used to represent scalar command line
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1575options, and is the one used most of the time. It is a templated class which
1576can take up to three arguments (all except for the first have default values
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1577though):</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1578
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1579<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1580<b>namespace</b> cl {
1581 <b>template</b> &lt;<b>class</b> DataType, <b>bool</b> ExternalStorage = <b>false</b>,
1582 <b>class</b> ParserClass = parser&lt;DataType&gt; &gt;
1583 <b>class</b> opt;
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1584}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1585</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1586
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1587<p>The first template argument specifies what underlying data type the command
1588line argument is, and is used to select a default parser implementation. The
1589second template argument is used to specify whether the option should contain
1590the storage for the option (the default) or whether external storage should be
1591used to contain the value parsed for the option (see <a href="#storage">Internal
1592vs External Storage</a> for more information).</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1593
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1594<p>The third template argument specifies which parser to use. The default value
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1595selects an instantiation of the <tt>parser</tt> class based on the underlying
1596data type of the option. In general, this default works well for most
1597applications, so this option is only used when using a <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1598href="#customparser">custom parser</a>.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1599
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1600</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1601
1602<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1603<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1604 <a name="cl::list">The <tt>cl::list</tt> class</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1605</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1606
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1607<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1608
1609<p>The <tt>cl::list</tt> class is the class used to represent a list of command
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1610line options. It too is a templated class which can take up to three
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1611arguments:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1612
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1613<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1614<b>namespace</b> cl {
1615 <b>template</b> &lt;<b>class</b> DataType, <b>class</b> Storage = <b>bool</b>,
1616 <b>class</b> ParserClass = parser&lt;DataType&gt; &gt;
1617 <b>class</b> list;
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1618}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1619</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1620
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1621<p>This class works the exact same as the <a
1622href="#cl::opt"><tt>cl::opt</tt></a> class, except that the second argument is
1623the <b>type</b> of the external storage, not a boolean value. For this class,
1624the marker type '<tt>bool</tt>' is used to indicate that internal storage should
1625be used.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1626
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1627</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1628
1629<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1630<h4>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]1631 <a name="cl::bits">The <tt>cl::bits</tt> class</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1632</h4>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]1633
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1634<div>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]1635
1636<p>The <tt>cl::bits</tt> class is the class used to represent a list of command
1637line options in the form of a bit vector. It is also a templated class which
1638can take up to three arguments:</p>
1639
1640<div class="doc_code"><pre>
1641<b>namespace</b> cl {
1642 <b>template</b> &lt;<b>class</b> DataType, <b>class</b> Storage = <b>bool</b>,
1643 <b>class</b> ParserClass = parser&lt;DataType&gt; &gt;
1644 <b>class</b> bits;
1645}
1646</pre></div>
1647
1648<p>This class works the exact same as the <a
1649href="#cl::opt"><tt>cl::lists</tt></a> class, except that the second argument
Jim Laskeyd6281ce2005-08-26 09:25:54 +0000[diff] [blame]1650must be of <b>type</b> <tt>unsigned</tt> if external storage is used.</p>
Jim Laskey295810d2005-08-25 22:52:43 +0000[diff] [blame]1651
1652</div>
1653
1654<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1655<h4>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1656 <a name="cl::alias">The <tt>cl::alias</tt> class</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1657</h4>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1658
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1659<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1660
1661<p>The <tt>cl::alias</tt> class is a nontemplated class that is used to form
1662aliases for other arguments.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1663
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1664<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1665<b>namespace</b> cl {
1666 <b>class</b> alias;
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1667}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1668</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1669
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1670<p>The <a href="#cl::aliasopt"><tt>cl::aliasopt</tt></a> attribute should be
1671used to specify which option this is an alias for. Alias arguments default to
1672being <a href="#cl::Hidden">Hidden</a>, and use the aliased options parser to do
1673the conversion from string to data.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1674
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1675</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1676
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1677<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1678<h4>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1679 <a name="cl::extrahelp">The <tt>cl::extrahelp</tt> class</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1680</h4>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1681
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1682<div>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1683
1684<p>The <tt>cl::extrahelp</tt> class is a nontemplated class that allows extra
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1685help text to be printed out for the <tt>-help</tt> option.</p>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1686
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1687<div class="doc_code"><pre>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1688<b>namespace</b> cl {
1689 <b>struct</b> extrahelp;
1690}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1691</pre></div>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1692
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]1693<p>To use the extrahelp, simply construct one with a <tt>const char*</tt>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1694parameter to the constructor. The text passed to the constructor will be printed
1695at the bottom of the help message, verbatim. Note that multiple
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1696<tt>cl::extrahelp</tt> <b>can</b> be used, but this practice is discouraged. If
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1697your tool needs to print additional help information, put all that help into a
1698single <tt>cl::extrahelp</tt> instance.</p>
1699<p>For example:</p>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1700<div class="doc_code"><pre>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1701 cl::extrahelp("\nADDITIONAL HELP:\n\n This is the extra help\n");
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1702</pre></div>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1703</div>
1704
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1705</div>
1706
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1707<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1708<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1709 <a name="builtinparsers">Builtin parsers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1710</h3>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1711
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1712<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1713
1714<p>Parsers control how the string value taken from the command line is
1715translated into a typed value, suitable for use in a C++ program. By default,
1716the CommandLine library uses an instance of <tt>parser&lt;type&gt;</tt> if the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1717command line option specifies that it uses values of type '<tt>type</tt>'.
1718Because of this, custom option processing is specified with specializations of
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1719the '<tt>parser</tt>' class.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1720
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1721<p>The CommandLine library provides the following builtin parser
1722specializations, which are sufficient for most applications. It can, however,
1723also be extended to work with new data types and new ways of interpreting the
1724same data. See the <a href="#customparser">Writing a Custom Parser</a> for more
1725details on this type of library extension.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1726
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1727<ul>
1728
1729<li><a name="genericparser">The <b>generic <tt>parser&lt;t&gt;</tt> parser</b></a>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1730can be used to map strings values to any data type, through the use of the <a
1731href="#cl::values">cl::values</a> property, which specifies the mapping
1732information. The most common use of this parser is for parsing enum values,
1733which allows you to use the CommandLine library for all of the error checking to
1734make sure that only valid enum values are specified (as opposed to accepting
1735arbitrary strings). Despite this, however, the generic parser class can be used
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1736for any data type.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1737
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1738<li><a name="boolparser">The <b><tt>parser&lt;bool&gt;</tt> specialization</b></a>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1739is used to convert boolean strings to a boolean value. Currently accepted
1740strings are "<tt>true</tt>", "<tt>TRUE</tt>", "<tt>True</tt>", "<tt>1</tt>",
Chris Lattner38751952009-04-08 03:43:51 +0000[diff] [blame]1741"<tt>false</tt>", "<tt>FALSE</tt>", "<tt>False</tt>", and "<tt>0</tt>".</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1742
Dale Johannesen10c5ccc2007-05-22 18:32:34 +0000[diff] [blame]1743<li><a name="boolOrDefaultparser">The <b><tt>parser&lt;boolOrDefault&gt;</tt>
1744 specialization</b></a> is used for cases where the value is boolean,
1745but we also need to know whether the option was specified at all. boolOrDefault
1746is an enum with 3 values, BOU_UNSET, BOU_TRUE and BOU_FALSE. This parser accepts
1747the same strings as <b><tt>parser&lt;bool&gt;</tt></b>.</li>
1748
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1749<li><a name="stringparser">The <b><tt>parser&lt;string&gt;</tt>
1750specialization</b></a> simply stores the parsed string into the string value
1751specified. No conversion or modification of the data is performed.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1752
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1753<li><a name="intparser">The <b><tt>parser&lt;int&gt;</tt> specialization</b></a>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1754uses the C <tt>strtol</tt> function to parse the string input. As such, it will
1755accept a decimal number (with an optional '+' or '-' prefix) which must start
1756with a non-zero digit. It accepts octal numbers, which are identified with a
1757'<tt>0</tt>' prefix digit, and hexadecimal numbers with a prefix of
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1758'<tt>0x</tt>' or '<tt>0X</tt>'.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1759
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1760<li><a name="doubleparser">The <b><tt>parser&lt;double&gt;</tt></b></a> and
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1761<b><tt>parser&lt;float&gt;</tt> specializations</b> use the standard C
1762<tt>strtod</tt> function to convert floating point strings into floating point
1763values. As such, a broad range of string formats is supported, including
1764exponential notation (ex: <tt>1.7e15</tt>) and properly supports locales.
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1765</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1766
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1767</ul>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1768
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1769</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1770
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1771</div>
1772
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1773<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1774<h2>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1775 <a name="extensionguide">Extension Guide</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1776</h2>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1777<!-- *********************************************************************** -->
1778
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1779<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1780
1781<p>Although the CommandLine library has a lot of functionality built into it
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1782already (as discussed previously), one of its true strengths lie in its
1783extensibility. This section discusses how the CommandLine library works under
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1784the covers and illustrates how to do some simple, common, extensions.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1785
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1786<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1787<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1788 <a name="customparser">Writing a custom parser</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1789</h3>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1790
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1791<div>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1792
1793<p>One of the simplest and most common extensions is the use of a custom parser.
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1794As <a href="#builtinparsers">discussed previously</a>, parsers are the portion
1795of the CommandLine library that turns string input from the user into a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1796particular parsed data type, validating the input in the process.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1797
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1798<p>There are two ways to use a new parser:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1799
1800<ol>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1801
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1802<li>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1803
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1804<p>Specialize the <a href="#genericparser"><tt>cl::parser</tt></a> template for
1805your custom data type.<p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1806
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1807<p>This approach has the advantage that users of your custom data type will
1808automatically use your custom parser whenever they define an option with a value
1809type of your data type. The disadvantage of this approach is that it doesn't
Jim Laskey88b5e792006-07-31 20:18:49 +0000[diff] [blame]1810work if your fundamental data type is something that is already supported.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1811
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1812</li>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1813
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1814<li>
1815
1816<p>Write an independent class, using it explicitly from options that need
1817it.</p>
1818
1819<p>This approach works well in situations where you would line to parse an
1820option using special syntax for a not-very-special data-type. The drawback of
1821this approach is that users of your parser have to be aware that they are using
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1822your parser instead of the builtin ones.</p>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1823
1824</li>
1825
1826</ol>
1827
1828<p>To guide the discussion, we will discuss a custom parser that accepts file
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1829sizes, specified with an optional unit after the numeric size. For example, we
1830would like to parse "102kb", "41M", "1G" into the appropriate integer value. In
1831this case, the underlying data type we want to parse into is
1832'<tt>unsigned</tt>'. We choose approach #2 above because we don't want to make
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1833this the default for all <tt>unsigned</tt> options.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1834
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1835<p>To start out, we declare our new <tt>FileSizeParser</tt> class:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1836
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1837<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1838<b>struct</b> FileSizeParser : <b>public</b> cl::basic_parser&lt;<b>unsigned</b>&gt; {
1839 <i>// parse - Return true on error.</i>
1840 <b>bool</b> parse(cl::Option &amp;O, <b>const char</b> *ArgName, <b>const</b> std::string &amp;ArgValue,
1841 <b>unsigned</b> &amp;Val);
1842};
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1843</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1844
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1845<p>Our new class inherits from the <tt>cl::basic_parser</tt> template class to
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1846fill in the default, boiler plate code for us. We give it the data type that
1847we parse into, the last argument to the <tt>parse</tt> method, so that clients of
1848our custom parser know what object type to pass in to the parse method. (Here we
1849declare that we parse into '<tt>unsigned</tt>' variables.)</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1850
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1851<p>For most purposes, the only method that must be implemented in a custom
1852parser is the <tt>parse</tt> method. The <tt>parse</tt> method is called
1853whenever the option is invoked, passing in the option itself, the option name,
1854the string to parse, and a reference to a return value. If the string to parse
Chris Lattner204e4a22008-01-09 19:28:50 +0000[diff] [blame]1855is not well-formed, the parser should output an error message and return true.
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1856Otherwise it should return false and set '<tt>Val</tt>' to the parsed value. In
1857our example, we implement <tt>parse</tt> as:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1858
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1859<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1860<b>bool</b> FileSizeParser::parse(cl::Option &amp;O, <b>const char</b> *ArgName,
1861 <b>const</b> std::string &amp;Arg, <b>unsigned</b> &amp;Val) {
1862 <b>const char</b> *ArgStart = Arg.c_str();
1863 <b>char</b> *End;
Anton Korobeynikov581ba342008-02-20 12:38:31 +0000[diff] [blame]1864
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1865 <i>// Parse integer part, leaving 'End' pointing to the first non-integer char</i>
1866 Val = (unsigned)strtol(ArgStart, &amp;End, 0);
1867
1868 <b>while</b> (1) {
1869 <b>switch</b> (*End++) {
Chris Lattnerd50b29a2005-08-22 16:24:25 +0000[diff] [blame]1870 <b>case</b> 0: <b>return</b> false; <i>// No error</i>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1871 <b>case</b> 'i': <i>// Ignore the 'i' in KiB if people use that</i>
1872 <b>case</b> 'b': <b>case</b> 'B': <i>// Ignore B suffix</i>
1873 <b>break</b>;
1874
1875 <b>case</b> 'g': <b>case</b> 'G': Val *= 1024*1024*1024; <b>break</b>;
1876 <b>case</b> 'm': <b>case</b> 'M': Val *= 1024*1024; <b>break</b>;
1877 <b>case</b> 'k': <b>case</b> 'K': Val *= 1024; <b>break</b>;
1878
1879 default:
1880 <i>// Print an error message if unrecognized character!</i>
Benjamin Kramer666cf9d2009-08-02 12:13:02 +0000[diff] [blame]1881 <b>return</b> O.error("'" + Arg + "' value invalid for file size argument!");
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1882 }
1883 }
1884}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1885</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1886
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1887<p>This function implements a very simple parser for the kinds of strings we are
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1888interested in. Although it has some holes (it allows "<tt>123KKK</tt>" for
1889example), it is good enough for this example. Note that we use the option
1890itself to print out the error message (the <tt>error</tt> method always returns
1891true) in order to get a nice error message (shown below). Now that we have our
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1892parser class, we can use it like this:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1893
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1894<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1895<b>static</b> <a href="#cl::opt">cl::opt</a>&lt;<b>unsigned</b>, <b>false</b>, FileSizeParser&gt;
1896MFS(<i>"max-file-size"</i>, <a href="#cl::desc">cl::desc</a>(<i>"Maximum file size to accept"</i>),
1897 <a href="#cl::value_desc">cl::value_desc</a>("<i>size</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1898</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1899
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1900<p>Which adds this to the output of our program:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1901
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1902<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1903OPTIONS:
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]1904 -help - display available options (-help-hidden for more)
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1905 ...
1906 <b>-max-file-size=&lt;size&gt; - Maximum file size to accept</b>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1907</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1908
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1909<p>And we can test that our parse works correctly now (the test program just
1910prints out the max-file-size argument value):</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1911
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1912<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1913$ ./test
1914MFS: 0
1915$ ./test -max-file-size=123MB
1916MFS: 128974848
1917$ ./test -max-file-size=3G
1918MFS: 3221225472
1919$ ./test -max-file-size=dog
1920-max-file-size option: 'dog' value invalid for file size argument!
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1921</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1922
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1923<p>It looks like it works. The error message that we get is nice and helpful,
1924and we seem to accept reasonable file sizes. This wraps up the "custom parser"
1925tutorial.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1926
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1927</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1928
1929<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1930<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1931 <a name="explotingexternal">Exploiting external storage</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1932</h3>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1933
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1934<div>
Reid Spencercf2bc3d2004-08-30 05:56:51 +0000[diff] [blame]1935 <p>Several of the LLVM libraries define static <tt>cl::opt</tt> instances that
1936 will automatically be included in any program that links with that library.
1937 This is a feature. However, sometimes it is necessary to know the value of the
1938 command line option outside of the library. In these cases the library does or
1939 should provide an external storage location that is accessible to users of the
1940 library. Examples of this include the <tt>llvm::DebugFlag</tt> exported by the
1941 <tt>lib/Support/Debug.cpp</tt> file and the <tt>llvm::TimePassesIsEnabled</tt>
1942 flag exported by the <tt>lib/VMCore/Pass.cpp</tt> file.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1943
Reid Spencercf2bc3d2004-08-30 05:56:51 +0000[diff] [blame]1944<p>TODO: complete this section</p>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1945
1946</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1947
1948<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1949<h3>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1950 <a name="dynamicopts">Dynamically adding command line options</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1951</h3>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1952
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1953<div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1954
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1955<p>TODO: fill in this section</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1956
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1957</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1958
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1959</div>
1960
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1961<!-- *********************************************************************** -->
1962
1963<hr>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1964<address>
1965 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1966 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1967 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1968 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1969
1970 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]1971 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman7120c832003-11-07 18:11:14 +0000[diff] [blame]1972 Last modified: $Date$
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1973</address>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1974
1975</body>
1976</html>