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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 18232a5fd177f629550c9be30ba1ed676ff0ca42 / . / docs / ReleaseNotes.html
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Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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4<head>
Reid Spencer6454ed32004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]7 <title>LLVM 2.2 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]10
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]11<div class="doc_title">LLVM 2.2 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]25
Chris Lattner052bae62008-02-06 18:00:48 +0000[diff] [blame]26
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]27<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]28<div class="doc_section">
29 <a name="intro">Introduction</a>
30</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]31<!-- *********************************************************************** -->
32
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]33<div class="doc_text">
34
35<p>This document contains the release notes for the LLVM compiler
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]36infrastructure, release 2.2. Here we describe the status of LLVM, including
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]37major improvements from the previous release and any known problems. All LLVM
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]38releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]39releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]40
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]41<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]42release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]43web site</a>. If you have questions or comments, the <a
44href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]45list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]46
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]47<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]48main LLVM web page, this document applies to the <i>next</i> release, not the
49current one. To see the release notes for a specific releases, please see the
50<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]51
52</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]53
54<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]55<div class="doc_section">
56 <a name="whatsnew">What's New?</a>
57</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]58<!-- *********************************************************************** -->
59
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]60<div class="doc_text">
61
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]62<p>This is the thirteenth public release of the LLVM Compiler Infrastructure.
63It includes many features and refinements from LLVM 2.1.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]64
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]65</div>
66
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]67<!-- Unfinished features in 2.2:
68 Index Set Splitting not enabled by default
69 Machine LICM
70 Machine Sinking
71 LegalizeDAGTypes
72 -->
73
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]74<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]75<div class="doc_subsection">
Chris Lattnerb4c68cd2008-02-10 07:04:35 +0000[diff] [blame]76<a name="deprecation">Deprecated features in LLVM 2.2</a>
77</div>
78
79<div class="doc_text">
80
81<p>This is the last LLVM release to support llvm-gcc 4.0, llvm-upgrade, and
82llvmc in its current form. llvm-gcc 4.0 has been replaced with llvm-gcc 4.2.
83llvm-upgrade is useful for upgrading llvm 1.9 files to llvm 2.x syntax, but you
84can always use an old release to do this. llvmc is currently mostly useless in
85llvm 2.2, and will be redesigned or removed in llvm 2.3.</p>
86
87</div>
88
89<!--=========================================================================-->
90<div class="doc_subsection">
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]91<a name="frontends">llvm-gcc 4.0, llvm-gcc 4.2, and clang</a>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]92</div>
93
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]94<div class="doc_text">
Chris Lattner60893e52007-05-18 06:33:02 +0000[diff] [blame]95
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]96<p>LLVM 2.2 fully supports both the llvm-gcc 4.0 and llvm-gcc 4.2 front-ends (in
97LLVM 2.1, llvm-gcc 4.2 was beta). Since LLVM 2.1, the llvm-gcc 4.2 front-end
98has made leaps and bounds and is now at least as good as 4.0 in virtually every
99area, and is better in several areas (for example, exception handling
Chris Lattnerdb401e92008-02-11 07:21:08 +0000[diff] [blame]100correctness, support for Ada and Fortran, better ABI compatibility, etc). We
101strongly recommend that you
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]102migrate from llvm-gcc 4.0 to llvm-gcc 4.2 in this release cycle because
103<b>LLVM 2.2 is the last release that will support llvm-gcc 4.0</b>: LLVM 2.3
104will only support the llvm-gcc 4.2 front-end.</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]105
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]106<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
107a set of new 'llvm native' front-end technologies for the LLVM optimizer
108and code generator. Currently, its C and Objective-C support is maturing
109nicely, and it has advanced source-to-source analysis and transformation
110capabilities. If you are interested in building source-level tools for C and
111Objective-C (and eventually C++), you should take a look. However, note that
112clang is not an official part of the LLVM 2.2 release. If you are interested in
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]113this project, please see its <a href="http://clang.llvm.org/">web site</a>.</p>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]114
115</div>
116
117<!--=========================================================================-->
118<div class="doc_subsection">
119<a name="majorfeatures">Major New Features</a>
120</div>
121
122<div class="doc_text">
123
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]124<p>LLVM 2.2 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]125
126<ul>
Scott Michel8c77ff92008-02-11 21:05:47 +0000[diff] [blame]127<li>A research team led by Scott Michel in the Computer Systems Research
128Department at The Aerospace Corporation contributed the CellSPU backend, which
129generates code for the vector coprocessors on the Sony/Toshiba/IBM Cell BE
130processor. llvm-gcc 4.2 supports CellSPU as a 'configure' target and progress
131is being made so that libgcc.a compiles cleanly. Notable pieces still in
132development include full 64-bit integer and full double precision floating
133point support.</li>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame]134
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]135<li>Anton and Duncan significantly improved llvm-gcc 4.2 support for the GCC Ada
136(GNAT) and Fortran (gfortran) front-ends. These front-ends should still be considered
137experimental however: see the <a href="#knownproblems">list of known problems</a>.
138The release binaries do not contain either front-end: they need to be built from
Chris Lattner6bbba662008-02-10 17:52:05 +0000[diff] [blame]139source (the Ada front-end only builds on x86-32 linux).</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]140
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]141<li>Dale contributed full support for long double on x86/x86-64 (where it is 80
142bits) and on Darwin PPC/PPC64 (where it is 128 bits). In previous LLVM
143releases, llvm-gcc silently mapped long double to double.</li>
Chris Lattner313d61f2008-02-09 22:58:07 +0000[diff] [blame]144
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]145<li>Gordon Henriksen rewrote most of the <a href="GarbageCollection.html"
146>Accurate Garbage Collection</a> code in the code generator, making the
Gabor Greif3f2a2092008-02-10 20:08:16 +0000[diff] [blame]147generated code more efficient and adding support for the OCaml garbage collector
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]148metadata format.</li>
149
150<li>Christopher Lamb contributed support for multiple address spaces in LLVM
151IR. This is useful for supporting targets that have 'near' vs 'far' pointers,
152'RAM' vs 'ROM' pointers, or that have non-local memory that can be accessed with
153special instructions.</li>
Chris Lattner313d61f2008-02-09 22:58:07 +0000[diff] [blame]154
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]155<li>LLVM now includes a new set of detailed <a
156href="tutorial/index.html">tutorials</a>, which explain how to implement a
157language with LLVM and shows how to use several important APIs.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]158
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]159</ul>
160
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]161</div>
162
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]163<!--=========================================================================-->
164<div class="doc_subsection">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]165<a name="coreimprovements">LLVM Core Improvements</a>
166</div>
167
168<div class="doc_text">
169<p>New features include:
170</p>
171
172<ul>
Gabor Greif3f2a2092008-02-10 20:08:16 +0000[diff] [blame]173<li>Gordon contributed support for C and OCaml Bindings for the basic LLVM IR
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]174construction routines as well as several other auxiliary APIs.</li>
175
176<li>Anton added readnone/readonly attributes for modeling function side effects.
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]177Duncan hooked up GCC's pure/const attributes to them and enhanced mod/ref
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]178analysis to use them.</li>
179
180<li>Devang added LLVMFoldingBuilder, a version of LLVMBuilder that implicitly
181simplifies the code as it is constructed.</li>
182
183<li>Ted Kremenek added a framework for generic object serialization to bitcode
184files. This support is only used by clang right now for ASTs but is extensible
185and could be used for serializing arbitrary other data into bitcode files.</li>
186
187<li>Duncan improved TargetData to distinguish between the size/alignment of a
188type in a register, in memory according to the platform ABI, and in memory when
189we have a choice.</li>
190
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]191<li>Reid moved parameter attributes off of FunctionType and onto functions
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]192and calls. This makes it much easier to add attributes to a function in a
193transformation pass.</li>
194
195<li>Dan Gohman added support for vector sin, cos, and pow intrinsics.</li>
196
197</ul>
198
199</div>
200
201<!--=========================================================================-->
202<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]203<a name="codegen">Code Generator Improvements</a>
204</div>
205
206<div class="doc_text">
207
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]208<p>We put a significant amount of work into the code generator infrastructure,
209which allows us to implement more aggressive algorithms and make it run
210faster:</p>
Chris Lattnerd4298712007-09-26 05:44:21 +0000[diff] [blame]211
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]212<ul>
213
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]214<li>Owen refactored the existing LLVM dominator and loop information code to
215allow it work on the machine code representation. He contributed support for
216dominator and loop information on machine code and merged the code for forward
217and backward dominator computation.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]218
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]219<li>Dan added support for emitting debug information with .file and .loc
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]220directives on platforms that support it, instead of emitting large tables in the .s
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]221file.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]222
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]223<li>Evan extended the DAG scheduler to model physical register dependencies
224explicitly and have the BURR scheduler pick a correct schedule based on the
225dependencies. This reduces our use of the 'flag' operand hack.</li>
Chris Lattner6b1a4ec2008-02-06 18:32:06 +0000[diff] [blame]226
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]227<li>Evan added initial support for register coalescing of subregister
228references.</li>
229
230<li>Rafael Espindola implemented initial support for a new 'byval' attribute,
231which allows more efficient by-value argument passing in the LLVM IR. Evan
232finished support for it and enabled it in the X86 (32- and 64-bit) and C
233backends.</li>
234
235<li>The LLVM TargetInstrInfo class can now answer queries about the mod/ref and
236side-effect behavior of MachineInstr's. This information is inferred
237automatically by TableGen from .td files for all instructions with
238patterns.</li>
239
240<li>Evan implemented simple live interval splitting on basic block boundaries.
241This allows the register allocator to be more successful at keeping values in
242registers in some parts of a value's live range, even if they need to be spilled
243in some other block.</li>
244
245<li>The new MachineRegisterInfo.h class provides support for efficiently
246iterating over all defs/uses of a register, and this information is
247automatically kept up-to-date. This support is similar to the use_iterator in
248the LLVM IR level.</li>
249
250<li>The MachineInstr, MachineOperand and TargetInstrDesc classes are simpler,
251more consistent, and better documented.</li>
252</ul>
253
254</div>
255
256<!--=========================================================================-->
257<div class="doc_subsection">
258<a name="optimizer">Optimizer Improvements</a>
259</div>
260
261<div class="doc_text">
262
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]263<p>In addition to a huge array of bug fixes and minor performance tweaks, the
264LLVM 2.2 optimizers support a few major enhancements:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]265
266<ul>
267
268<li>Daniel Berlin and Curtis Dunham rewrote Andersen's alias analysis to be
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]269several orders of magnitude faster, and implemented Offline Variable
270Substitution and Lazy Cycle Detection. Note that Andersen's is not enabled in
271llvm-gcc by default, but can be accessed through 'opt'.</li>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]272
273<li>Dan Gohman contributed several enhancements to Loop Strength Reduction (LSR)
Chris Lattnerdb401e92008-02-11 07:21:08 +0000[diff] [blame]274to make it more aggressive with SSE intrinsics and when induction variables are
275used by non-memory instructions.</li>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]276
277<li>Evan added support for simple exit value substitution to LSR.</li>
278
Chris Lattner313d61f2008-02-09 22:58:07 +0000[diff] [blame]279<li>Evan enhanced LSR to support induction variable reuse when the induction
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]280variables have different widths.</li>
Chris Lattner313d61f2008-02-09 22:58:07 +0000[diff] [blame]281
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]282</ul>
283
284</div>
285
286
287<!--=========================================================================-->
288<div class="doc_subsection">
289<a name="targetspecific">Target Specific Improvements</a>
290</div>
Chris Lattner60893e52007-05-18 06:33:02 +0000[diff] [blame]291
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]292<div class="doc_text">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]293<p>New target-specific features include:
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]294</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]295
296<ul>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]297<li>Evan contributed support to the X86 backend to model the mod/ref behavior
298of the EFLAGS register explicitly in all instructions. This gives more freedom
299to the scheduler, and is a more explicit way to model the instructions.</li>
Chris Lattner786cb7e2008-02-11 07:27:21 +0000[diff] [blame]300<li>Dale contributed support for exception handling on Darwin/PPC and he and
301Anton got x86-64 working.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]302<li>Evan turned on if-conversion by default for ARM, allowing LLVM to take
303advantage of its predication features.</li>
304<li>Bruno added PIC support to the MIPS backend, fixed many bugs and improved
305support for architecture variants.</li>
Chris Lattner02b81fe2008-02-12 05:07:12 +0000[diff] [blame]306<li>Arnold Schwaighofer added initial support for X86 tail calls.</li>
307<li>Evan contributed several enhancements to Darwin/x86 debug information.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]308<li>Duncan added x86-64 support for trampolines (pointers to nested functions).</li>
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]309</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]310
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]311</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]312
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]313<!--=========================================================================-->
314<div class="doc_subsection">
315<a name="otherimprovements">Other Improvements</a>
316</div>
317
318<div class="doc_text">
319<p>New features include:
320</p>
321
322<ul>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]323<li>Gordon expanded and updated the <a href="Passes.html">LLVM Analysis and
324Transformation Passes</a> reference to include descriptions for each pass.</li>
325
326<li>We rewrote the lexer and parser used by TableGen to make them simpler
327and cleaner. This gives tblgen support for 'caret diagnostics'. The .ll file
328lexer was also rewritten to support caret diagnostics but doesn't use this
329support yet.</li>
330
331<li>Dale has been grinding through the GCC testsuite, and marked many
332LLVM-incompatible tests as not-to-be-run (for example, if they are grepping
333through some GCC dump file that LLVM doesn't produce), he also found and fixed
334many LLVM bugs exposed by the testsuite.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]335</ul>
336
337</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]338
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]339<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]340<div class="doc_section">
341 <a name="portability">Portability and Supported Platforms</a>
342</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]343<!-- *********************************************************************** -->
344
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]345<div class="doc_text">
346
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]347<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]348
349<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]350<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]351 (and probably other unix-like systems).</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]352<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]353 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]354<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]355<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
356 support is available for native builds with Visual C++).</li>
357<li>Sun UltraSPARC workstations running Solaris 8.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]358<li>Alpha-based machines running Debian GNU/Linux.</li>
359<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]360</ul>
361
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]362<p>The core LLVM infrastructure uses
363<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
364to the machine and operating system on which it is built. However, minor
365porting may be required to get LLVM to work on new platforms. We welcome your
366portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]367
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]368</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]369
370<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]371<div class="doc_section">
372 <a name="knownproblems">Known Problems</a>
373</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]374<!-- *********************************************************************** -->
375
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]376<div class="doc_text">
377
378<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]379component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]380sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]381href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]382there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]383
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]384</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]385
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]386<!-- ======================================================================= -->
387<div class="doc_subsection">
388 <a name="experimental">Experimental features included with this release</a>
389</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]390
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]391<div class="doc_text">
392
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]393<p>The following components of this LLVM release are either untested, known to
394be broken or unreliable, or are in early development. These components should
395not be relied on, and bugs should not be filed against them, but they may be
396useful to some people. In particular, if you would like to work on one of these
Chris Lattner49e693e2006-08-09 04:08:52 +0000[diff] [blame]397components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]398
399<ul>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]400<li>The <tt>-cee</tt> pass is known to be buggy and will be removed in
401 LLVM 2.3.</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]402<li>The MSIL, IA64, Alpha, and MIPS backends are experimental.</li>
403<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
404 value for this option.</li>
405<li>The llvmc tool is not supported.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]406</ul>
407
408</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]409
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]410<!-- ======================================================================= -->
411<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]412 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]413</div>
414
415<div class="doc_text">
416
417<ul>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]418<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]419 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]420<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
421 problems</a> on operating systems that don't require 16-byte stack alignment
422 (including most non-darwin OS's like linux).</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]423<li>The X86 backend generates inefficient floating point code when configured to
424 generate code for systems that don't have SSE2.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]425</ul>
426
427</div>
428
429<!-- ======================================================================= -->
430<div class="doc_subsection">
431 <a name="ppc-be">Known problems with the PowerPC back-end</a>
432</div>
433
434<div class="doc_text">
435
436<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]437<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]438compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]439</ul>
440
441</div>
442
443<!-- ======================================================================= -->
444<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]445 <a name="arm-be">Known problems with the ARM back-end</a>
446</div>
447
448<div class="doc_text">
449
450<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]451<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]452processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]453results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]454<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
455</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]456<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly execute
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]457programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]458</ul>
459
460</div>
461
462<!-- ======================================================================= -->
463<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]464 <a name="sparc-be">Known problems with the SPARC back-end</a>
465</div>
466
467<div class="doc_text">
468
469<ul>
470<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
471 support the 64-bit SPARC ABI (-m64).</li>
472</ul>
473
474</div>
475
476<!-- ======================================================================= -->
477<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]478 <a name="alpha-be">Known problems with the Alpha back-end</a>
479</div>
480
481<div class="doc_text">
482
483<ul>
484
485<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
486appropriate nops inserted to ensure restartability.</li>
487
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]488</ul>
489</div>
490
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]491<!-- ======================================================================= -->
492<div class="doc_subsection">
493 <a name="ia64-be">Known problems with the IA64 back-end</a>
494</div>
495
496<div class="doc_text">
497
498<ul>
499
500<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
501made where the argument is not 16-byte aligned, as required on IA64. (Strictly
502speaking this is not a bug in the IA64 back-end; it will also be encountered
503when building C++ programs using the C back-end.)</li>
504
505<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
506ABI compliant layout of v-tables</a>. In particular, it just stores function
507pointers instead of function descriptors in the vtable. This bug prevents
508mixing C++ code compiled with LLVM with C++ objects compiled by other C++
509compilers.</li>
510
511<li>There are a few ABI violations which will lead to problems when mixing LLVM
512output with code built with other compilers, particularly for floating-point
513programs.</li>
514
515<li>Defining vararg functions is not supported (but calling them is ok).</li>
516
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]517<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]518</ul>
519
520</div>
521
522<!-- ======================================================================= -->
523<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]524 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]525</div>
526
527<div class="doc_text">
528
529<ul>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]530<li><a href="http://llvm.org/PR802">The C backend does not support inline
531 assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]532<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
533 yet</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]534<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
535 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
536 C++ code compiled with LLC or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]537<li>The C backend does not support all exception handling constructs.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]538</ul>
539
540</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]541
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]542
543<!-- ======================================================================= -->
544<div class="doc_subsection">
545 <a name="c-fe">Known problems with the C front-end</a>
546</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]547
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]548<!-- ======================================================================= -->
549<div class="doc_subsection">
550 <a name="ada-fe">Known problems with the Ada front-end</a>
551</div>
552
553<div class="doc_text">
554The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
555technology and problems should be expected.
556<ul>
557<li>The Ada front-end currently only builds on x86-32. This is mainly due
558to lack of trampoline support (pointers to nested functions) on other platforms,
559however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
560which does support trampolines.</li>
561<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
562Workaround: configure with --disable-bootstrap.</li>
563<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
564fail (c380004 also fails with gcc-4.2 mainline).</li>
565<li>Many gcc specific Ada tests continue to crash the compiler.</li>
566<li>The -E binder option (exception backtraces)
567<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
568crashing if an exception is raised. Workaround: do not use -E.</li>
569<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
570or finish at a non-byte offset</a> in a record. Workaround: do not pack records
571or use representation clauses that result in a field of a non-discrete type
572starting or finishing in the middle of a byte.</li>
573<li>The lli interpreter <a href="http://llvm.org/PR2009">considers 'main'
574as generated by the Ada binder to be invalid</a>.
575Workaround: hand edit the file to use pointers for argv and envp rather than
576integers.</li>
577<li>The -fstack-check option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
578</ul>
579</div>
580
581<!-- ======================================================================= -->
582<div class="doc_subsection">
583 <a name="fortran-fe">Known problems with the Fortran front-end</a>
584</div>
585
586<div class="doc_text">
587
588<ul>
589<li>The llvm-gcc 4.2 gfortran front-end supports a broad range of Fortran code, but does
590<a href="http://llvm.org/PR1971">not support EQUIVALENCE yet</a>.</li>
591</ul>
592</div>
593
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]594<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]595<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]596
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]597<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]598
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]599<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
600Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]601llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]602
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]603</div>
604
605<!-- _______________________________________________________________________ -->
606<div class="doc_subsubsection">
607 Notes
608</div>
609
610<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]611<ul>
612
Chris Lattnerd09c4ec2007-05-17 22:02:24 +0000[diff] [blame]613<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
614 See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
615</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]616
Duncan Sands32a83442007-05-18 09:04:20 +0000[diff] [blame]617<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]618 <ol>
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]619 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>:
620
621 As in Algol and Pascal, lexical scoping of functions.
622 Nested functions are supported, but llvm-gcc does not support
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]623 taking the address of a nested function (except on X86 targets)
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]624 or non-local gotos.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]625
626 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]627
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]628 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]629 return.<br>
630
Anton Korobeynikovbe6fe282007-11-16 11:12:01 +0000[diff] [blame]631 <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
632 <tt>const</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Anton Korobeynikov9413de32006-11-18 08:04:48 +0000[diff] [blame]633 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
Anton Korobeynikovbe6fe282007-11-16 11:12:01 +0000[diff] [blame]634 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noinline</tt>,
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]635 <tt>noreturn</tt>, <tt>nothrow</tt>, <tt>pure</tt>, <tt>regparm</tt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]636 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
637 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]638
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]639 <b>Ignored:</b> <tt>malloc</tt>,
Anton Korobeynikovbe6fe282007-11-16 11:12:01 +0000[diff] [blame]640 <tt>no_instrument_function</tt></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]641 </ol>
Chris Lattnerd09c4ec2007-05-17 22:02:24 +0000[diff] [blame]642</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]643
Chris Lattnerd09c4ec2007-05-17 22:02:24 +0000[diff] [blame]644<li><p>llvm-gcc supports the vast majority of GCC extensions, including:</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]645
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]646 <ol>
Chris Lattnerd09c4ec2007-05-17 22:02:24 +0000[diff] [blame]647 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
648 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
649 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
650 Other built-in functions.</li>
651 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
652 Specifying attributes of variables.</li>
653 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.</li>
654 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
655 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
656 Arrays whose length is computed at run time.</li>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000[diff] [blame]657 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html#Labels%20as%20Values">Labels as Values</a>: Getting pointers to labels and computed gotos.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]658 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
659 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
Tanya Lattnerca26c3e2004-06-22 03:48:17 +0000[diff] [blame]660 <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]661 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
662 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
663 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
664 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
665 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
666 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
667 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.</li>
668 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]669 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.</li>
670 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
671 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Asm-Labels.html#Asm%20Labels">Asm Labels</a>: Specifying the assembler name to use for a C symbol.</li>
672 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>: Defining variables residing in specified registers.</li>
673 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.</li>
674 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]675 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.</li>
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]676 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html#Pointer%20Arith">Pointer Arith</a>: Arithmetic on <code>void</code>-pointers and function pointers.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]677 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]678 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
679or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]680 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]681 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html#Cast%20to%20Union">Cast to Union</a>: Casting to union type from any member of the union.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]682 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
683 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
684 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
Tanya Lattner78537e42004-12-08 18:29:38 +0000[diff] [blame]685 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]686 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
687 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Character-Escapes.html#Character%20Escapes">Character Escapes</a>: <code>\e</code> stands for the character &lt;ESC&gt;.</li>
688 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
689 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
690 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alternate-Keywords.html#Alternate%20Keywords">Alternate Keywords</a>:<code>__const__</code>, <code>__asm__</code>, etc., for header files.</li>
691 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Incomplete-Enums.html#Incomplete%20Enums">Incomplete Enums</a>: <code>enum foo;</code>, with details to follow.</li>
692 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html#Function%20Names">Function Names</a>: Printable strings which are the name of the current function.</li>
Chris Lattner25795bc2004-02-14 04:08:29 +0000[diff] [blame]693 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Return-Address.html#Return%20Address">Return Address</a>: Getting the return or frame address of a function.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]694 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.</li>
695 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]696 </ol></li>
697
698</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]699
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]700<p>If you run into GCC extensions which have not been included in any of these
701lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]702
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]703</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]704
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]705<!-- ======================================================================= -->
706<div class="doc_subsection">
707 <a name="c++-fe">Known problems with the C++ front-end</a>
708</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]709
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]710<div class="doc_text">
711
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]712<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]713tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]714itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]715
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]716<ul>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]717<li>Exception handling only works well on the X86 and PowerPC targets.
718It works well for x86-64 darwin but not x86-64 linux.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]719</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]720
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]721</div>
722
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]723
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]724
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]725<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]726<div class="doc_section">
727 <a name="additionalinfo">Additional Information</a>
728</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]729<!-- *********************************************************************** -->
730
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]731<div class="doc_text">
732
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]733<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]734href="http://llvm.org">LLVM web page</a>, in particular in the <a
735href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]736contains versions of the API documentation which is up-to-date with the
737Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]738You can access versions of these documents specific to this release by going
739into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]740
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]741<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]742us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]743lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]744
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]745</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]746
747<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]748
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]749<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]750<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]751 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]752 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
753 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]754 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]755
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]756 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]757 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]758</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]759
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]760</body>
761</html>