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5 <title>The LLVM Compiler Driver (llvmc)</title>
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Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]15 <meta name="author" content="Reid Spencer">
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]16 <meta name="description"
17 content="A description of the use and design of the LLVM Compiler Driver.">
18</head>
19<body>
20<div class="doc_title">The LLVM Compiler Driver (llvmc)</div>
21<p class="doc_warning">NOTE: This document is a work in progress!</p>
22<ol>
23 <li><a href="#abstract">Abstract</a></li>
24 <li><a href="#introduction">Introduction</a>
25 <ol>
26 <li><a href="#purpose">Purpose</a></li>
27 <li><a href="#operation">Operation</a></li>
28 <li><a href="#phases">Phases</a></li>
29 <li><a href="#actions">Actions</a></li>
30 </ol>
31 </li>
32 <li><a href="#details">Details</a>
33 <li><a href="#configuration">Configuration</a>
34 <li><a href="#glossary">Glossary</a>
35</ol>
36<div class="doc_author">
37<p>Written by <a href="mailto:rspencer@x10sys.com">Reid Spencer</a>
38</p>
39</div>
40
41<!-- *********************************************************************** -->
42<div class="doc_section"> <a name="abstract">Abstract</a></div>
43<!-- *********************************************************************** -->
44<div class="doc_text">
45 <p>This document describes the requirements, design, and configuration of the
46 LLVM compiler driver, <tt>llvmc</tt>. The compiler driver knows about LLVM's
47 tool set and can be configured to know about a variety of compilers for
48 source languages. It uses this knowledge to execute the tools necessary
49 to accomplish general compilation, optimization, and linking tasks. The main
50 purpose of <tt>llvmc</tt> is to provide a simple and consistent interface to
51 all compilation tasks. This reduces the burden on the end user who can just
52 learn to use <tt>llvmc</tt> instead of the entire LLVM tool set and all the
53 source language compilers compatible with LLVM.</p>
54</div>
55<!-- *********************************************************************** -->
56<div class="doc_section"> <a name="introduction">Introduction</a></div>
57<!-- *********************************************************************** -->
58<div class="doc_text">
59 <p>The <tt>llvmc</tt> <a href="def_tool">tool</a> is a configurable compiler
60 <a href="def_driver">driver</a>. As such, it isn't the compiler, optimizer,
61 or linker itself but it drives (invokes) other software that perform those
62 tasks. If you are familiar with the GNU Compiler Collection's <tt>gcc</tt>
63 tool, <tt>llvmc</tt> is very similar.</p>
64 <p>The following introductory sections will help you understand why this tool
65 is necessary and what it does.</p>
66</div>
67
68<!-- _______________________________________________________________________ -->
69<div class="doc_subsection"><a name="purpose">Purpose</a></div>
70<div class="doc_text">
71 <p><tt>llvmc</tt> was invented to make compilation with LLVM based compilers
72 easier. To accomplish this, <tt>llvmc</tt> strives to:</p>
73 <ul>
74 <li>Be the single point of access to most of the LLVM tool set.</li>
75 <li>Hide the complexities of the LLVM tools through a single interface.</li>
76 <li>Provide a consistent interface for compiling all languages.</li>
77 </ul>
78 <p>Additionally, <tt>llvmc</tt> makes it easier to write a compiler for use
79 with LLVM, because it:</p>
80 <ul>
81 <li>Makes integration of existing non-LLVM tools simple.</li>
82 <li>Extends the capabilities of minimal front ends by optimizing their
83 output.</li>
84 <li>Reduces the number of interfaces a compiler writer must know about
85 before a working compiler can be completed (essentially only the VMCore
86 interfaces need to be understood).</li>
87 <li>Supports source language translator invocation via both dynamically
88 loadable shared objects and invocation of an executable.</li>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]89 </ul>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]90</div>
91
92<!-- _______________________________________________________________________ -->
93<div class="doc_subsection"><a name="operation">Operation</a></div>
94<div class="doc_text">
95 <p>At a high level, <tt>llvmc</tt> operation is very simple. The basic action
96 taken by <tt>llvmc</tt> is to simply invoke some tool or set of tools to fill
97 the user's request for compilation. Every execution of <tt>llvmc</tt>takes the
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]98 following sequence of steps:</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]99 <dl>
100 <dt><b>Collect Command Line Options</b></dt>
101 <dd>The command line options provide the marching orders to <tt>llvmc</tt>
102 on what actions it should perform. This is the request the user is making
103 of <tt>llvmc</tt> and it is interpreted first. See the <tt>llvmc</tt>
104 <a href="CommandGuide/html/llvmc.html">manual page</a> for details on the
105 options.</dd>
106 <dt><b>Read Configuration Files</b></dt>
107 <dd>Based on the options and the suffixes of the filenames presented, a set
108 of configuration files are read to configure the actions <tt>llvmc</tt> will
109 take. Configuration files are provided by either LLVM or the front end
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]110 compiler tools that <tt>llvmc</tt> invokes. These files determine what
111 actions <tt>llvmc</tt> will take in response to the user's request. See
112 the section on <a href="#configuration">configuration</a> for more details.
113 </dd>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]114 <dt><b>Determine Phases To Execute</b></dt>
115 <dd>Based on the command line options and configuration files,
116 <tt>llvmc</tt> determines the compilation <a href="#phases">phases</a> that
117 must be executed by the user's request. This is the primary work of
118 <tt>llvmc</tt>.</dd>
119 <dt><b>Determine Actions To Execute</b></dt>
120 <dd>Each <a href="#phases">phase</a> to be executed can result in the
121 invocation of one or more <a href="#actions">actions</a>. An action is
122 either a whole program or a function in a dynamically linked shared library.
123 In this step, <tt>llvmc</tt> determines the sequence of actions that must be
124 executed. Actions will always be executed in a deterministic order.</dd>
125 <dt><b>Execute Actions</b></dt>
126 <dd>The <a href="#actions">actions</a> necessary to support the user's
127 original request are executed sequentially and deterministically. All
128 actions result in either the invocation of a whole program to perform the
129 action or the loading of a dynamically linkable shared library and invocation
130 of a standard interface function within that library.</dd>
131 <dt><b>Termination</b></dt>
132 <dd>If any action fails (returns a non-zero result code), <tt>llvmc</tt>
133 also fails and returns the result code from the failing action. If
134 everything succeeds, <tt>llvmc</tt> will return a zero result code.</dd>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]135 </dl>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]136 <p><tt>llvmc</tt>'s operation must be simple, regular and predictable.
137 Developers need to be able to rely on it to take a consistent approach to
138 compilation. For example, the invocation:</p>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]139 <code>
140 llvmc -O2 x.c y.c z.c -o xyz</code>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]141 <p>must produce <i>exactly</i> the same results as:</p>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]142 <code>
143 llvmc -O2 x.c
144 llvmc -O2 y.c
145 llvmc -O2 z.c
146 llvmc -O2 x.o y.o z.o -o xyz</code>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]147 <p>To accomplish this, <tt>llvmc</tt> uses a very simple goal oriented
148 procedure to do its work. The overall goal is to produce a functioning
149 executable. To accomplish this, <tt>llvmc</tt> always attempts to execute a
150 series of compilation <a href="#def_phase">phases</a> in the same sequence.
151 However, the user's options to <tt>llvmc</tt> can cause the sequence of phases
152 to start in the middle or finish early.</p>
153</div>
154
155<!-- _______________________________________________________________________ -->
156<div class="doc_subsection"><a name="phases"></a>Phases </div>
157<div class="doc_text">
158 <p><tt>llvmc</tt> breaks every compilation task into the following five
159 distinct phases:</p>
160 <dl><dt><b>Preprocessing</b></dt><dd>Not all languages support preprocessing;
161 but for those that do, this phase can be invoked. This phase is for
162 languages that provide combining, filtering, or otherwise altering with the
163 source language input before the translator parses it. Although C and C++
164 are the most common users of this phase, other languages may provide their
165 own preprocessor (whether its the C pre-processor or not).</dd>
166 </dl>
167 <dl><dt><b>Translation</b></dt><dd>The translation phase converts the source
168 language input into something that LLVM can interpret and use for
169 downstream phases. The translation is essentially from "non-LLVM form" to
170 "LLVM form".</dd>
171 </dl>
172 <dl><dt><b>Optimization</b></dt><dd>Once an LLVM Module has been obtained from
173 the translation phase, the program enters the optimization phase. This phase
174 attempts to optimize all of the input provided on the command line according
175 to the options provided.</dd>
176 </dl>
177 <dl><dt><b>Linking</b></dt><dd>The inputs are combined to form a complete
178 program.</dd>
179 </dl>
180 <p>The following table shows the inputs, outputs, and command line options
181 applicabe to each phase.</p>
182 <table>
183 <tr>
184 <th style="width: 10%">Phase</th>
185 <th style="width: 25%">Inputs</th>
186 <th style="width: 25%">Outputs</th>
187 <th style="width: 40%">Options</th>
188 </tr>
189 <tr><td><b>Preprocessing</b></td>
190 <td class="td_left"><ul><li>Source Language File</li></ul></td>
191 <td class="td_left"><ul><li>Source Language File</li></ul></td>
192 <td class="td_left"><dl>
193 <dt><tt>-E</tt></dt>
194 <dd>Stops the compilation after preprocessing</dd>
195 </dl></td>
196 </tr>
197 <tr>
198 <td><b>Translation</b></td>
199 <td class="td_left"><ul>
200 <li>Source Language File</li>
201 </ul></td>
202 <td class="td_left"><ul>
203 <li>LLVM Assembly</li>
204 <li>LLVM Bytecode</li>
205 <li>LLVM C++ IR</li>
206 </ul></td>
207 <td class="td_left"><dl>
208 <dt><tt>-c</tt></dt>
209 <dd>Stops the compilation after translation so that optimization and
210 linking are not done.</dd>
211 <dt><tt>-S</tt></dt>
212 <dd>Stops the compilation before object code is written so that only
213 assembly code remains.</dd>
214 </dl></td>
215 </tr>
216 <tr>
217 <td><b>Optimization</b></td>
218 <td class="td_left"><ul>
219 <li>LLVM Assembly</li>
220 <li>LLVM Bytecode</li>
221 </ul></td>
222 <td class="td_left"><ul>
223 <li>LLVM Bytecode</li>
224 </ul></td>
225 <td class="td_left"><dl>
226 <dt><tt>-Ox</tt>
227 <dd>This group of options affects the amount of optimization
228 performed.</dd>
229 </dl></td>
230 </tr>
231 <tr>
232 <td><b>Linking</b></td>
233 <td class="td_left"><ul>
234 <li>LLVM Bytecode</li>
235 <li>Native Object Code</li>
236 <li>LLVM Library</li>
237 <li>Native Library</li>
238 </ul></td>
239 <td class="td_left"><ul>
240 <li>LLVM Bytecode Executable</li>
241 <li>Native Executable</li>
242 </ul></td>
243 <td class="td_left"><dl>
244 <dt><tt>-L</tt></dt><dd>Specifies a path for library search.</dd>
245 <dt><tt>-l</tt></dt><dd>Specifies a library to link in.</dd>
246 </dl></td>
247 </tr>
248 </table>
249</div>
250
251<!-- _______________________________________________________________________ -->
252<div class="doc_subsection"><a name="actions"></a>Actions</div>
253<div class="doc_text">
254 <p>An action, with regard to <tt>llvmc</tt> is a basic operation that it takes
255 in order to fulfill the user's request. Each phase of compilation will invoke
256 zero or more actions in order to accomplish that phase.</p>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]257 <p>Actions come in two forms:</p>
258 <ul>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]259 <li>Invokable Executables</li>
260 <li>Functions in a shared library</li>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]261 </ul>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]262</div>
263
264<!-- *********************************************************************** -->
265<div class="doc_section"><a name="details">Details</a></div>
266<!-- *********************************************************************** -->
267<div class="doc_text">
268</div>
269
270<!-- *********************************************************************** -->
271<div class="doc_section"><a name="configuration">Configuration</a></div>
272<!-- *********************************************************************** -->
273<div class="doc_text">
274 <p>This section of the document describes the configuration files used by
275 <tt>llvmc</tt>. Configuration information is relatively static for a
276 given release of LLVM and a front end compiler. However, the details may
277 change from release to release of either. Users are encouraged to simply use
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]278 the various options of the <tt>llvmc</tt> command and ignore the configuration
279 of the tool. These configuration files are for compiler writers and LLVM
280 developers. Those wishing to simply use <tt>llvmc</tt> don't need to understand
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]281 this section but it may be instructive on how the tool works.</p>
282</div>
283
284<!-- _______________________________________________________________________ -->
285<div class="doc_subsection"><a name="overview"></a>Overview</div>
286<div class="doc_text">
287<p><tt>llvmc</tt> is highly configurable both on the command line and in
288configuration files. The options it understands are generic, consistent and
289simple by design. Furthermore, the <tt>llvmc</tt> options apply to the
290compilation of any LLVM enabled programming language. To be enabled as a
291supported source language compiler, a compiler writer must provide a
292configuration file that tells <tt>llvmc</tt> how to invoke the compiler
293and what its capabilities are. The purpose of the configuration files then
294is to allow compiler writers to specify to <tt>llvmc</tt> how the compiler
295should be invoked. Users may but are not advised to alter the compiler's
296<tt>llvmc</tt> configuration.</p>
297
298<p>Because <tt>llvmc</tt> just invokes other programs, it must deal with the
299available command line options for those programs regardless of whether they
300were written for LLVM or not. Furthermore, not all compilation front ends will
301have the same capabilities. Some front ends will simply generate LLVM assembly
302code, others will be able to generate fully optimized byte code. In general,
303<tt>llvmc</tt> doesn't make any assumptions about the capabilities or command
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]304line options of a sub-tool. It simply uses the details found in the
305configuration files and leaves it to the compiler writer to specify the
306configuration correctly.</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]307
308<p>This approach means that new compiler front ends can be up and working very
309quickly. As a first cut, a front end can simply compile its source to raw
310(unoptimized) bytecode or LLVM assembly and <tt>llvmc</tt> can be configured
311to pick up the slack (translate LLVM assembly to bytecode, optimize the
312bytecode, generate native assembly, link, etc.). In fact, the front end need
313not use any LLVM libraries, and it could be written in any language (instead of
314C++). The configuration data will allow the full range of optimization,
315assembly, and linking capabilities that LLVM provides to be added to these kinds
316of tools. Enabling the rapid development of front-ends is one of the primary
317goals of <tt>llvmc</tt>.</p>
318
319<p>As a compiler front end matures, it may utilize the LLVM libraries and tools
320to more efficiently produce optimized bytecode directly in a single compilation
321and optimization program. In these cases, multiple tools would not be needed
322and the configuration data for the compiler would change.</p>
323
324<p>Configuring <tt>llvmc</tt> to the needs and capabilities of a source language
325compiler is relatively straight forward. A compiler writer must provide a
326definition of what to do for each of the five compilation phases for each of
327the optimization levels. The specification consists simply of prototypical
328command lines into which <tt>llvmc</tt> can substitute command line
329arguments and file names. Note that any given phase can be completely blank if
330the source language's compiler combines multiple phases into a single program.
331For example, quite often pre-processing, translation, and optimization are
332combined into a single program. The specification for such a compiler would have
333blank entries for pre-processing and translation but a full command line for
334optimization.</p>
335</div>
336
337<!-- _______________________________________________________________________ -->
338<div class="doc_subsection"><a name="filetypes"></a>Configuration Files</div>
339<div class="doc_text">
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]340 <h3>File Contents</h3>
341 <p>Each configuration file provides the details for a single source language
342 that is to be compiled. This configuration information tells <tt>llvmc</tt>
343 how to invoke the language's pre-processor, translator, optimizer, assembler
344 and linker. Note that a given source language needn't provide all these tools
345 as many of them exist in llvm currently.</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]346
347 <h3>Directory Search</h3>
348 <p><tt>llvmc</tt> always looks for files of a specific name. It uses the
349 first file with the name its looking for by searching directories in the
350 following order:<br/>
351 <ol>
352 <li>Any directory specified by the <tt>--config-dir</tt> option will be
353 checked first.</li>
354 <li>If the environment variable LLVM_CONFIG_DIR is set, and it contains
355 the name of a valid directory, that directory will be searched next.</li>
356 <li>If the user's home directory (typically <tt>/home/user</tt> contains
357 a sub-directory named <tt>.llvm</tt> and that directory contains a
358 sub-directory named <tt>etc</tt> then that directory will be tried
359 next.</li>
360 <li>If the LLVM installation directory (typically <tt>/usr/local/llvm</tt>
361 contains a sub-directory named <tt>etc</tt> then that directory will be
362 tried last.</li>
363 <li>If the configuration file sought still can't be found, <tt>llvmc</tt>
364 will print an error message and exit.</li>
365 </ol>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]366 <p>The first file found in this search will be used. Other files with the
367 same name will be ignored even if they exist in one of the subsequent search
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]368 locations.</p>
369
370 <h3>File Names</h3>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]371 <p>In the directories searched, each configuration file is given a specific
372 name to foster faster lookup (so llvmc doesn't have to do directory searches).
373 The name of a given language specific configuration file is simply the same
374 as the suffix used to identify files containing source in that language.
375 For example, a configuration file for C++ source might be named
376 <tt>cpp</tt>, <tt>C</tt>, or <tt>cxx</tt>. For languages that support multiple
377 file suffixes, multiple (probably identical) files (or symbolic links) will
378 need to be provided.</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]379
380 <h3>What Gets Read</h3>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]381 <p>Which configuration files are read depends on the command line options and
382 the suffixes of the file names provided on <tt>llvmc</tt>'s command line. Note
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]383 that the <tt>--x LANGUAGE</tt> option alters the language that <tt>llvmc</tt>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]384 uses for the subsequent files on the command line. Only the configuration
385 files actually needed to complete <tt>llvmc</tt>'s task are read. Other
386 language specific files will be ignored.</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]387</div>
388
389<!-- _______________________________________________________________________ -->
390<div class="doc_subsection"><a name="syntax"></a>Syntax</div>
391<div class="doc_text">
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]392 <p>The syntax of the configuration files is very simple and somewhat
393 compatible with Java's property files. Here are the syntax rules:</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]394 <ul>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]395 <li>The file encoding is ASCII.</li>
396 <li>The file is line oriented. There should be one configuration item per
397 line. Lines are terminated by the newline character (0x0A).</li>
398 <li>A configuration item consists of a name, an <tt>=</tt> and a value.</li>
399 <li>A name consists of a sequence of identifiers separated by period.</li>
400 <li>An identifier consists of specific keywords made up of only lower case
401 and upper case letters (e.g. <tt>lang.name</tt>).</li>
402 <li>Values come in four flavors: booleans, integers, commands and
403 strings.</li>
404 <li>Valid "false" boolean values are <tt>false False FALSE no No NO
405 off Off</tt> and <tt>OFF</tt>.</li>
406 <li>Valid "true" boolean values are <tt>true True TRUE yes Yes YES
407 on On</tt> and <tt>ON</tt>.</li>
408 <li>Integers are simply sequences of digits.</li>
409 <li>Commands start with a program name and are followed by a sequence of
410 words that are passed to that program as command line arguments. Program
411 arguments that begin and end with the <tt>@</tt> sign will have their value
412 substituted. Program names beginning with <tt>/</tt> are considered to be
413 absolute. Otherwise the <tt>PATH</tt> will be applied to find the program to
414 execute.</li>
415 <li>Strings are composed of multiple sequences of characters from the
416 character class <tt>[-A-Za-z0-9_:%+/\\|,]</tt> separated by white
417 space.</li>
418 <li>White space on a line is folded. Multiple blanks or tabs will be
419 reduced to a single blank.</li>
420 <li>White space before the configuration item's name is ignored.</li>
421 <li>White space on either side of the <tt>=</tt> is ignored.</li>
422 <li>White space in a string value is used to separate the individual
423 components of the string value but otherwise ignored.</li>
424 <li>Comments are introduced by the <tt>#</tt> character. Everything after a
425 <tt>#</tt> and before the end of line is ignored.</li>
426 </ul>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]427</div>
428
429<!-- _______________________________________________________________________ -->
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]430<div class="doc_subsection"><a name="items">Configuration Items</a></div>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]431<div class="doc_text">
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]432 <p>The table below provides definitions of the allowed configuration items
433 that may appear in a configuration file. Every item has a default value and
434 does not need to appear in the configuration file. Missing items will have the
435 default value. Each identifier may appear as all lower case, first letter
436 capitalized or all upper case.</p>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]437 <table>
438 <tr>
439 <th>Name</th>
440 <th>Value Type</th>
441 <th>Description</th>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]442 <th>Default</th>
443 </tr>
444 <tr><td colspan="4"><h4>LANG ITEMS</h4></td></tr>
445 <tr>
446 <td><b>lang.name</b></td>
447 <td>string</td>
448 <td class="td_left">Provides the common name for a language definition.
449 For example "C++", "Pascal", "FORTRAN", etc.</td>
450 <td><i>blank</i></td>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]451 </tr>
452 <tr>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]453 <td><b>lang.opt1</b></td>
454 <td>string</td>
455 <td class="td_left">Specifies the parameters to give the optimizer when <tt>-O1</tt> is
456 specified on the <tt>llvmc</tt> command line.</td>
457 <td><tt>-simplifycfg -instcombine -mem2reg</tt></td>
458 </tr>
459 <tr>
460 <td><b>lang.opt2</b></td>
461 <td>string</td>
462 <td class="td_left">Specifies the parameters to give the optimizer when <tt>-O2</tt> is
463 specified on the <tt>llvmc</tt> command line.</td>
464 <td><i>TBD</i></td>
465 </tr>
466 <tr>
467 <td><b>lang.opt3</b></td>
468 <td>string</td>
469 <td class="td_left">Specifies the parameters to give the optimizer when <tt>-O3</tt> is
470 specified on the <tt>llvmc</tt> command line.</td>
471 <td><i>TBD</i></td>
472 </tr>
473 <tr>
474 <td><b>lang.opt4</b></td>
475 <td>string</td>
476 <td class="td_left">Specifies the parameters to give the optimizer when <tt>-O4</tt> is
477 specified on the <tt>llvmc</tt> command line.</td>
478 <td><i>TBD</i></td>
479 </tr>
480 <tr>
481 <td><b>lang.opt5</b></td>
482 <td>string</td>
483 <td class="td_left">Specifies the parameters to give the optimizer when <tt>-O5</tt> is
484 specified on the <tt>llvmc</tt> command line.</td>
485 <td><i>TBD</i></td>
486 </tr>
487 <tr><td colspan="4"><h4>PREPROCESSOR ITEMS</h4></td></tr>
488 <tr>
489 <td><b>preprocessor.command</b></td>
490 <td>command</td>
491 <td class="td_left">This provides the command prototype that will be used
492 to run the preprocessor. Valid substitutions are <tt>@in@</tt> for the
493 input file and <tt>@out@</tt> for the output file. This is generally only
494 used with the <tt>-E</tt> option.</td>
495 <td>&lt;blank&gt;</td>
496 </tr>
497 <tr>
498 <td><b>preprocessor.required</b></td>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]499 <td>boolean</td>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]500 <td class="td_left">This item specifies whether the pre-processing phase
501 is required by the language. If the value is true, then the
502 <tt>preprocessor.command</tt> value must not be blank. With this option,
503 <tt>llvmc</tt> will always run the preprocessor as it assumes that the
504 translation and optimization phases don't know how to pre-process their
505 input.</td>
506 <td>false</td>
507 </tr>
508 <tr><td colspan="4"><h4>TRANSLATOR ITEMS</h4></td></tr>
509 <tr>
510 <td><b>translator.command</b></td>
511 <td>command</td>
512 <td class="td_left">This provides the command prototype that will be used
513 to run the translator. Valid substitutions are <tt>@in@</tt> for the
514 input file and <tt>@out@</tt> for the output file.</td>
515 <td>&lt;blank&gt;</td>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]516 </tr>
517 <tr>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]518 <td><b>translator.output</b></td>
519 <td><tt>native</tt>, <tt>bytecode</tt> or <tt>assembly</tt></td>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]520 <td class="td_left">This item specifies the kind of output the language's
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]521 translator generates.</td>
522 <td><tt>bytecode</tt></td>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]523 </tr>
524 <tr>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]525 <td><b>translator.preprocesses</b></td>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]526 <td>boolean</td>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]527 <td class="td_left">Indicates that the translator also preprocesses. If this is true, then
528 <tt>llvmc</tt> will skip the pre-processing phase whenever the final
529 phase is not pre-processing.</td>
530 <td><tt>false</tt></td>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]531 </tr>
Reid Spenceraaa3da92004-08-17 09:18:37 +0000[diff] [blame]532 <tr>
533 <td><b>translator.optimizers</b></td>
534 <td>boolean</td>
535 <td class="td_left">Indicates that the translator also optimizes. If this is true, then
536 <tt>llvmc</tt> will skip the optimization phase whenever the final phase
537 is optimization or later.</td>
538 <td><tt>false</tt></td>
539 </tr>
540 <tr>
541 <td><b>translator.groks_dash_o</b></td>
542 <td>boolean</td>
543 <td class="td_left">Indicates that the translator understands the <i>intent</i> of the
544 various <tt>-O</tt><i>n</i> options to <tt>llvmc</tt>. This will cause the
545 <tt>-O</tt><i>n</i> option to be based to the translator instead of the
546 equivalent options provided by <tt>lang.opt</tt><i>n</i>.</td>
547 <td><tt>false</tt></td>
548 </tr>
549 <tr><td colspan="4"><h4>OPTIMIZER ITEMS</h4></td></tr>
550 <tr><td colspan="4"><h4>ASSEMBLER ITEMS</h4></td></tr>
551 <tr><td colspan="4"><h4>LINKER ITEMS</h4></td></tr>
Reid Spencera2aa3042004-08-10 16:40:56 +0000[diff] [blame]552 </table>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]553</div>
554
555<!-- *********************************************************************** -->
556<div class="doc_section"><a name="glossary">Glossary</a></div>
557<!-- *********************************************************************** -->
558<div class="doc_text">
559 <p>This document uses precise terms in reference to the various artifacts and
560 concepts related to compilation. The terms used throughout this document are
561 defined below.</p>
562 <dl>
563 <dt><a name="def_assembly"><b>assembly</b></a></dt>
564 <dd>A compilation <a href="#def_phase">phase</a> in which LLVM bytecode or
565 LLVM assembly code is assembled to a native code format (either target
566 specific aseembly language or the platform's native object file format).
567 </dd>
568
569 <dt><a name="def_compiler"><b>compiler</b></a></dt>
570 <dd>Refers to any program that can be invoked by <tt>llvmc</tt> to accomplish
571 the work of one or more compilation <a href="#def_phase">phases</a>.</dd>
572
573 <dt><a name="def_driver"><b>driver</b></a></dt>
574 <dd>Refers to <tt>llvmc</tt> itself.</dd>
575
576 <dt><a name="def_linking"><b>linking</b></a></dt>
577 <dd>A compilation <a href="#def_phase">phase</a> in which LLVM bytecode files
578 and (optionally) native system libraries are combined to form a complete
579 executable program.</dd>
580
581 <dt><a name="def_optimization"><b>optimization</b></a></dt>
582 <dd>A compilation <a href="#def_phase">phase</a> in which LLVM bytecode is
583 optimized.</dd>
584
585 <dt><a name="def_phase"><b>phase</b></a></dt>
586 <dd>Refers to any one of the five compilation phases that that
587 <tt>llvmc</tt> supports. The five phases are:
588 <a href="#def_preprocessing">preprocessing</a>,
589 <a href="#def_translation">translation</a>,
590 <a href="#def_optimization">optimization</a>,
591 <a href="#def_assembly">assembly</a>,
592 <a href="#def_linking">linking</a>.</dd>
593
594 <dt><a name="def_sourcelanguage"><b>source language</b></a></dt>
595 <dd>Any common programming language (e.g. C, C++, Java, Stacker, ML,
596 FORTRAN). These languages are distinguished from any of the lower level
597 languages (such as LLVM or native assembly), by the fact that a
598 <a href="#def_translation">translation</a> <a href="#def_phase">phase</a>
599 is required before LLVM can be applied.</dd>
600
601 <dt><a name="def_tool"><b>tool</b></a></dt>
602 <dd>Refers to any program in the LLVM tool set.</dd>
603
604 <dt><a name="def_translation"><b>translation</b></a></dt>
605 <dd>A compilation <a href="#def_phase">phase</a> in which
606 <a href="#def_sourcelanguage">source language</a> code is translated into
607 either LLVM assembly language or LLVM bytecode.</dd>
608 </dl>
609</div>
610<!-- *********************************************************************** -->
611<hr>
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616 href="mailto:rspencer@x10sys.com">Reid Spencer</a><br>
617<a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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