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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / f910fd3110e1809b64153f0ba2a9c9b6f520f86e / . / docs / ReleaseNotes.html
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Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]7 <title>LLVM 2.5 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 Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]11<div class="doc_title">LLVM 2.5 Release Notes</div>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]12
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]13<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]14 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]15 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]16 <li><a href="#externalproj">External Projects Using LLVM 2.5</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]17 <li><a href="#whatsnew">What's New in LLVM?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]18 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#portability">Portability and Supported Platforms</a></li>
Dan Gohman44aa9212008-10-14 16:23:02 +0000[diff] [blame]20 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]21 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]22</ol>
23
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]24<div class="doc_author">
Dan Gohman44aa9212008-10-14 16:23:02 +0000[diff] [blame]25 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]26</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]27
28<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]29<div class="doc_section">
30 <a name="intro">Introduction</a>
31</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]32<!-- *********************************************************************** -->
33
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]34<div class="doc_text">
35
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]36<p>This document contains the release notes for the LLVM Compiler
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]37Infrastructure, release 2.5. Here we describe the status of LLVM, including
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]38major improvements from the previous release and significant known problems.
39All LLVM releases may be downloaded from the <a
40href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]41
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]42<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]43release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]44web site</a>. If you have questions or comments, the <a
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
46List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]47
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]48<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]49main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greiffa933f82008-10-14 11:00:32 +0000[diff] [blame]50current one. To see the release notes for a specific release, please see the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]51<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]52
53</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]54
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]55<!-- Unfinished features in 2.5:
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]56 Machine LICM
57 Machine Sinking
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]58 target-specific intrinsics
59 gold lto plugin
Chris Lattner99f375b2009-02-25 07:32:53 +0000[diff] [blame]60 pre-alloc splitter, strong phi elim
Chris Lattner547a3912008-10-12 19:47:48 +0000[diff] [blame]61 llc -enable-value-prop, propagation of value info (sign/zero ext info) from
62 one MBB to another
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]63 debug info for optimized code
Chris Lattnerc1771e32009-02-26 07:29:17 +0000[diff] [blame]64 interpreter + libffi
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]65 postalloc scheduler: anti dependence breaking, hazard recognizer?
66
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]67 -->
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]68
Chris Lattner547a3912008-10-12 19:47:48 +0000[diff] [blame]69 <!-- for announcement email:
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]70 -->
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]71
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]72<!-- *********************************************************************** -->
73<div class="doc_section">
74 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]75</div>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]76<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]77
78<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]79<p>
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]80The LLVM 2.5 distribution currently consists of code from the core LLVM
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]81repository (which roughly includes the LLVM optimizers, code generators and
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]82supporting tools) and the llvm-gcc repository. In addition to this code, the
83LLVM Project includes other sub-projects that are in development. The two which
Chris Lattner857fb132008-10-11 18:18:28 +0000[diff] [blame]84are the most actively developed are the <a href="#clang">Clang Project</a> and
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]85the <a href="#vmkit">VMKit Project</a>.
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]86</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]87
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]88</div>
89
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]90
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]91<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]92<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]93<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]94</div>
95
96<div class="doc_text">
97
98<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
99a set of new 'LLVM native' front-end technologies for the LLVM optimizer
Chris Lattnerf40c40b2009-02-25 05:09:54 +0000[diff] [blame]100and code generator. While Clang is not included in the LLVM 2.5 release, it
101is continuing to make major strides forward in all areas. Its C and Objective-C
102parsing and code generation support is now very solid. For example, it is
103capable of successfully building many real applications for X86-32 and X86-64,
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]104including <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">the FreeBSD
105kernel</a>. C++ is also making <a
Chris Lattnerf40c40b2009-02-25 05:09:54 +0000[diff] [blame]106href="http://clang.llvm.org/cxx_status.html">incredible progress</a>, and work
107on templates has recently started.</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]108
Chris Lattnerf40c40b2009-02-25 05:09:54 +0000[diff] [blame]109<p>While Clang is not yet production quality, it is progressing very nicely and
110is quite usable for building many C and Objective-C applications. If you are
111interested in fast compiles and good diagnostics, we encourage you to try it out
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]112by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
Chris Lattnerf40c40b2009-02-25 05:09:54 +0000[diff] [blame]113and reporting any issues you hit to the <a
114href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
115list</a>.</p>
116
117<p>In the LLVM 2.5 time-frame, the Clang team has made many improvements:</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000[diff] [blame]118
Daniel Dunbar13739432008-10-14 23:25:09 +0000[diff] [blame]119<ul>
Chris Lattnerf40c40b2009-02-25 05:09:54 +0000[diff] [blame]120<li>Clang now has a new driver, which is focused on providing a GCC-compatible
121 interface.</li>
122<li>The X86-64 ABI is now supported.</li>
123<li>Precompiled header support is now implemented.</li>
124<li>Objective-C support is significantly improved beyond LLVM 2.4, supporting
125 many features, such as Objective-C Garbage Collection.</li>
126<li>Many many bugs are fixed.</li>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]127</div>
128
129<!--=========================================================================-->
130<div class="doc_subsection">
131<a name="clangsa">Clang Static Analyzer</a>
132</div>
133
134<div class="doc_text">
135
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000[diff] [blame]136<p>Previously announced in the last LLVM release, the Clang project also
137includes an early stage static source code analysis tool for <a
138href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
139in C and Objective-C programs. The tool performs a growing set of checks to find
140bugs that occur on a specific path within a program.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000[diff] [blame]141
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000[diff] [blame]142<p>In the LLVM 2.5 time-frame there have been many significant improvements to
143the analyzer's core path simulation engine and machinery for generating
144path-based bug reports to end-users. Particularly noteworthy improvements
145include experimental support for full field-sensitivity and reasoning about heap
146objects as well as an improved value-constraints subengine that does a much
147better job of reasoning about inequality relationships (e.g., <tt>x &gt; 2</tt>)
148between variables and constants.
Ted Kremenek3c3ec0c2008-10-14 05:14:21 +0000[diff] [blame]149
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000[diff] [blame]150<p>The set of checks performed by the static analyzer continue to expand, and
151future plans for the tool include full source-level inter-procedural analysis
152and deeper checks such as buffer overrun detection. There are many opportunities
153to extend and enhance the static analyzer, and anyone interested in working on
154this project is encouraged to get involved!</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]155
156</div>
157
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]158<!--=========================================================================-->
159<div class="doc_subsection">
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]160<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]161</div>
162
163<div class="doc_text">
164<p>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]165The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]166a JVM and a CLI Virtual Machines (Microsoft .NET is an
167implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
168
Chris Lattner1f859862009-02-25 05:45:05 +0000[diff] [blame]169<p>Following LLVM 2.5, VMKit has its first release ? that you can find on its
Nicolas Geoffray56d313d2008-10-15 20:25:04 +0000[diff] [blame]170<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes
171bug fixes, cleanup and new features. The major changes are:</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]172
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]173<ul>
174
Chris Lattner75e26ca2009-02-26 05:20:36 +0000[diff] [blame]175<li>Ahead of Time compiler: compiles .class files to llvm .bc. VMKit uses this
176functionality to native compile the standard classes (eg java.lang.String).
177Users can compile AOT .class files into dynamic libraries and run them with the
178help of VMKit.</li>
179
180<li>New exception model: the dwarf exception model is very slow for
181exception-intensive applications, so the JVM has had a new implementation of
182exceptions which check at each function call if an exception happened. There is
183a low performance penalty on applications without exceptions, but it is a big
184gain for exception-intensive applications. For example the jack benchmark in
185Spec JVM98 is 6x faster (performance gain of 83%).</li>
186
187<li>New support for OSX/X64, Linux/X64 (with the Boehm GC), Linux/ppc32.</li>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]188
189</ul>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]190</div>
191
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]192<!-- *********************************************************************** -->
193<div class="doc_section">
194 <a name="externalproj">External Projects Using LLVM 2.5</a>
195</div>
196<!-- *********************************************************************** -->
197
198<!--=========================================================================-->
199<div class="doc_subsection">
200<a name="pure">Pure</a>
201</div>
202
203<div class="doc_text">
204<p>
205http://pure-lang.googlecode.com/
206</p>
207
208<p>
209Pure is an algebraic/functional programming language based on term rewriting.
210Programs are collections of equations which are used to evaluate expressions in
211a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
212lexical closures, a hygienic macro system (also based on term rewriting),
213built-in list and matrix support (including list and matrix comprehensions) and
214an easy-to-use C interface. The interpreter uses LLVM as a backend to
215 JIT-compile Pure programs to fast native code.</p>
216
217<p>In addition to the usual algebraic data structures, Pure also has
218MATLAB-style matrices in order to support numeric computations and signal
219processing in an efficient way. Pure is mainly aimed at mathematical
220applications right now, but it has been designed as a general purpose language.
221The dynamic interpreter environment and the C interface make it possible to use
222it as a kind of functional scripting language for many application areas.
223</p>
224</div>
225
226
227<!--=========================================================================-->
228<div class="doc_subsection">
229<a name="ldc">LLVM D Compiler</a>
230</div>
231
232<div class="doc_text">
233<p>
234http://www.dsource.org/projects/ldc
235</p>
236
237<p>
238I'd like to inform that the LDC project (LLVM D
239Compiler) is working with release 2.5 of LLVM. In fact we've required
2402.5 in our trunk since the release was branched.
241The improvements in 2.5 have fixed a lot of problems with LDC, more
242specifically the new inline asm constraints, better debug info
243support, general bugfixes :) and better x86-64 support have allowed
244some major improvements in LDC, getting us much closer to being as
245fully featured as the original DMD compiler from DigitalMars.
246</p>
247</div>
248
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000[diff] [blame]249<!--=========================================================================-->
250<div class="doc_subsection">
251<a name="RoadsendPHP">Roadsend PHP</a>
252</div>
253
254<div class="doc_text">
255<p>http://code.roadsend.com/rphp</p>
256
257<p>Roadsend PHP is using LLVM for code generation. This is an open source
258project.
259</p>
260</div>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]261
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]262
263<!-- *********************************************************************** -->
264<div class="doc_section">
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]265 <a name="whatsnew">What's New in LLVM?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]266</div>
267<!-- *********************************************************************** -->
268
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]269<div class="doc_text">
270
Bill Wendling741748a2008-10-27 09:27:33 +0000[diff] [blame]271<p>This release includes a huge number of bug fixes, performance tweaks, and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]272minor improvements. Some of the major improvements and new features are listed
273in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]274</p>
275</div>
276
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]277<!--=========================================================================-->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]278<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]279<a name="majorfeatures">Major New Features</a>
280</div>
281
282<div class="doc_text">
283
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]284<p>LLVM 2.5 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]285
286<ul>
Duncan Sands8524cb92009-02-25 11:37:39 +0000[diff] [blame]287<li><p>The code generator now supports arbitrary precision integers.
288Types like <tt>i33</tt> have long been valid in the LLVM IR, but previously
289could only be used with the interpreter.
290Now IR using such types can be compiled to native code on all targets.
291All operations are supported if the integer is not bigger than twice the
292target machine word size.
293Simple operations like loads, stores and shifts by a constant amount are
294supported for integers of any size.
295</p></li>
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]296
297<!--
298Random stuff:
299
Chris Lattnerc1771e32009-02-26 07:29:17 +0000[diff] [blame]300Pure project: http://code.google.com/p/pure-lang/
301
302
Chris Lattner99f375b2009-02-25 07:32:53 +0000[diff] [blame]303xcore backend!
304fortran on darwin!
305
Chris Lattnerc1771e32009-02-26 07:29:17 +0000[diff] [blame]306.ll parser rewrite, caret diags, better errors, less fragile (less likely to
307 crash on strange things). No longer depends on flex/bison.
Chris Lattnerd838fcd2009-02-26 06:47:09 +0000[diff] [blame]308GCC inliner off, llvm handles always-inline.
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]309cmake mature?
Chris Lattnerc1771e32009-02-26 07:29:17 +0000[diff] [blame]310x86 backend GS segment -> addr space 256 (r62980)
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]311nocapture
Duncan Sandsf910fd32009-03-01 08:26:19 +0000[diff] [blame^]312addreadattrs pass renamed to functionattrs; now calculates nocapture
Chris Lattnerd838fcd2009-02-26 06:47:09 +0000[diff] [blame]313memdep (used by GVN and memcpyopt) is faster / more aggressive.
Chris Lattner99f375b2009-02-25 07:32:53 +0000[diff] [blame]314how to write a backend doc docs/WritingAnLLVMBackend.html
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]315fastisel + exception handling
316vector widening <3 x float> -> <4 x float>
Chris Lattner99f375b2009-02-25 07:32:53 +0000[diff] [blame]317arm port improvements? arm jit encoding stuff, constant island support?
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]318JIT TLS support on x86-32 but not x86-64.
Chris Lattner99f375b2009-02-25 07:32:53 +0000[diff] [blame]319mem2reg now faster on code with huge basic blocks
320stack protectors/stack canaries, -fstack-protector, controllable on a
321 per-function basis with attributes.
322shufflevector is generalized to allow different shuffle mask width than its
323 input vectors.
324loop optimizer improves floating point induction variables
325llvm/Analysis/DebugInfo.h classes, llvm-gcc and clang and codegen use them.
Chris Lattnerc1771e32009-02-26 07:29:17 +0000[diff] [blame]326 DebugInfoBuilder gone.
Chris Lattner99f375b2009-02-25 07:32:53 +0000[diff] [blame]327asmprinters seperate from targets for jits
Chris Lattner75e26ca2009-02-26 05:20:36 +0000[diff] [blame]328PBQP register allocator now supports register coalescing.
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]329JIT supports exceptions on linux/x86-64 and linux/x86-64.
Chris Lattnerd838fcd2009-02-26 06:47:09 +0000[diff] [blame]330integer overflow intrinsics for [us](add/sub/mul). Supported on all targets,
331 but only generates efficient code on x86.
332X86 backend now supports -disable-mmx.
333noalias attribute on return value indicates that function returns new memory
334 (e.g. malloc).
Chris Lattnerd838fcd2009-02-26 06:47:09 +0000[diff] [blame]335llvmc2 renamed to llvmc
336Jump threading more powerful: it is iterative, handles threading based on values
337 with fully redundant and partially redundant loads.
338LSR improvements?
339ARM debug info support?
340unit test framework based on Google Test.
341
342vector shift support + X86 backend.
Chris Lattnerc1771e32009-02-26 07:29:17 +0000[diff] [blame]343x86 JIT now detects core i7 and atom, autoconfiguring itself appropriately.
344SROA is more aggressive about promoting unions.
345non-zero __builtin_return_address values on X86.
346x86-64 now uses red zone (unless -mno-red-zone option is specified).
347private linkage.
Chris Lattner75e26ca2009-02-26 05:20:36 +0000[diff] [blame]348
Chris Lattnerc1771e32009-02-26 07:29:17 +0000[diff] [blame]349llvm-gcc defaults to -fno-math-errno on all x86 targets.
350
351initial support for debug line numbers when optimization enabled, not useful in
352 2.5 but will be for 2.6.
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]353-->
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]354
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]355</ul>
356
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]357</div>
358
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]359
360<!--=========================================================================-->
361<div class="doc_subsection">
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]362<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]363</div>
364
365<div class="doc_text">
366
Chris Lattnerb82eb062008-10-13 20:47:20 +0000[diff] [blame]367<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC
368front-ends and driver with the LLVM optimizer and code generator. It currently
369includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]370
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]371<ul>
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]372<li>?</li>
Gabor Greifa3bd11d2008-06-09 06:06:18 +0000[diff] [blame]373</ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]374
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]375</div>
376
377
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]378<!--=========================================================================-->
379<div class="doc_subsection">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]380<a name="coreimprovements">LLVM Core Improvements</a>
381</div>
382
383<div class="doc_text">
Bill Wendling741748a2008-10-27 09:27:33 +0000[diff] [blame]384<p>New features include:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]385
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]386<ul>
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]387<li>?</li>
Chris Lattner7752d1a2008-10-13 20:59:32 +0000[diff] [blame]388
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]389</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]390
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]391</div>
392
393<!--=========================================================================-->
394<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]395<a name="optimizer">Optimizer Improvements</a>
396</div>
397
398<div class="doc_text">
399
Chris Lattnerf3013872008-10-13 21:50:36 +0000[diff] [blame]400<p>In addition to a huge array of bug fixes and minor performance tweaks, this
401release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]402
403<ul>
404
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]405<li>?</li>
Chris Lattnerf3013872008-10-13 21:50:36 +0000[diff] [blame]406
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]407</ul>
408
409</div>
410
411<!--=========================================================================-->
412<div class="doc_subsection">
413<a name="codegen">Code Generator Improvements</a>
414</div>
415
416<div class="doc_text">
417
Gabor Greifa8b84902008-10-14 11:31:14 +0000[diff] [blame]418<p>We have put a significant amount of work into the code generator infrastructure,
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]419which allows us to implement more aggressive algorithms and make it run
420faster:</p>
421
422<ul>
Duncan Sands07636ea2009-02-25 11:50:08 +0000[diff] [blame]423<li>The type legalization logic has been completely rewritten, and is now
424more powerful (it supports arbitrary precision integer types for example)
425and hopefully more correct.
426The type legalizer converts operations on types that are not natively
427supported by the target machine into equivalent code sequences that only use
428natively supported types.
429The old type legalizer is still available and will be used if
430<tt>-disable-legalize-types</tt> is passed to <tt>llc</tt>.
431</li>
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]432<li>?</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]433
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]434</ul>
435
436</div>
437
438
439<!--=========================================================================-->
440<div class="doc_subsection">
Chris Lattner11398992009-02-26 07:32:11 +0000[diff] [blame]441<a name="pic16">PIC16 Target Improvements</a>
442</div>
443
444<div class="doc_text">
445<p>New features of the PIC16 target include:
446</p>
447
448<ul>
449<li>Both direct and indirect load/stores work now.</li>
450<li>Logical, bitwise and conditional operations now work for integer data
451types.</li>
452<li>Function calls involving basic types work now.</li>
453<li>Support for integer arrays.</li>
454<li>Compiler can now emit libcalls for operations not support by m/c insns.</li>
455<li>Support for both data and rom address spaces.</li>
456</li>
457</ul>
458
459<p>Things not yet supported:</p>
460
461<ul>
462<li>Floating point.</li>
463<li>Passing/returning aggregate types to/from functions.</li>
464<li>Variable arguments.</li>
465<li>Indirect function calls.</li>
466<li>Interrupts/prgrams.</li>
467<li>Debug info.</li>
468</li>
469</ul>
470
471</div>
472
473
474<!--=========================================================================-->
475<div class="doc_subsection">
476<a name="othertargetspecific">Other Target Specific Improvements</a>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]477</div>
Chris Lattner60893e52007-05-18 06:33:02 +0000[diff] [blame]478
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]479<div class="doc_text">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]480<p>New target-specific features include:
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]481</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]482
483<ul>
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]484<li>?</li>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]485</ul>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]486
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]487</div>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]488
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]489<!--=========================================================================-->
490<div class="doc_subsection">
491<a name="llvmc">Improvements in LLVMC</a>
492</div>
493
494<div class="doc_text">
495<p>New features include:</p>
496
497<ul>
498<li>Beginning with LLVM 2.5, llvmc2 is known as just 'llvmc'. The
499 old llvmc driver was removed.</li>
500
501<li>The Clang plugin was substantially improved and is now enabled
502 by default. The command 'llvmc --clang' can be now used as a
503 synonym to 'ccc'.</li>
504
505<li>There is now a '--check-graph' option which is supposed to
506 catch common errors like multiple default edges, mismatched
507 output/input language names and cycles. In general, these
508 checks can't be done at compile-time because of the need to
509 support plugins.</li>
510
511<li>Plugins are now more flexible and can refer to compilation
512 graph nodes and options defined in other plugins. To manage
513 dependencies, a priority-sorting mechanism was introduced. This
514 change affects the '.td' file syntax; see the documentation for
515 details.</li>
516
517<li>Hooks can now be provided with arguments. The syntax
518 is "$CALL(MyHook, 'Arg1', 'Arg2', 'Arg #3')".</li>
519
520<li>A new option type: multi-valued option, for options that take
521 more than one argument (for example, "-foo a b c").</li>
522
523<li>New option properties: 'one_or_more', 'zero_or_more', 'hidden'
524 and 'really_hidden'.</li>
525
526<li>The 'case' expression gained an 'error' action and an 'empty'
527 test (equivalent to '(not (not_empty ...))').</li>
528
529<li>Documentation now looks more consistent to the rest of the LLVM
530 docs. There is also a man page now.</li>
531
532</ul>
533
534</div>
535
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]536
537<!--=========================================================================-->
538<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]539<a name="otherimprovements">Other Improvements</a>
540</div>
541
542<div class="doc_text">
543<p>New features include:
544</p>
545
546<ul>
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]547<li>?</li>
Tanya Lattnera7ec7062008-11-04 18:40:27 +0000[diff] [blame]548
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]549</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]550
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]551</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]552
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]553<!--=========================================================================-->
554<div class="doc_subsection">
555<a name="changes">Major Changes and Removed Features</a>
556</div>
557
558<div class="doc_text">
559
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]560<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]561on LLVM 2.4, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]562from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]563
564<ul>
565
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]566<li>?</li>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]567</ul>
568
569
570<p>In addition, many APIs have changed in this release. Some of the major LLVM
571API changes are:</p>
572
573<ul>
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]574<li>?</li>
Devang Patelb34dd132008-10-14 20:03:43 +0000[diff] [blame]575</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]576
Chris Lattner38ab04c2009-02-25 04:41:31 +0000[diff] [blame]577<li>?</li>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]578</ul>
579
580</div>
581
582
583
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]584<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]585<div class="doc_section">
586 <a name="portability">Portability and Supported Platforms</a>
587</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]588<!-- *********************************************************************** -->
589
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]590<div class="doc_text">
591
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]592<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]593
594<ul>
Chris Lattnere18b32e2008-11-10 05:40:34 +0000[diff] [blame]595<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
596Linux, Fedora Core and FreeBSD (and probably other unix-like systems).</li>
597<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
598and 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]599<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]600<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
601 support is available for native builds with Visual C++).</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]602<li>Sun UltraSPARC workstations running Solaris 10.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]603<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]604<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]605</ul>
606
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]607<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]608to the machine and operating system on which it is built. However, minor
609porting may be required to get LLVM to work on new platforms. We welcome your
610portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]611
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]612</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]613
614<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]615<div class="doc_section">
616 <a name="knownproblems">Known Problems</a>
617</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]618<!-- *********************************************************************** -->
619
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]620<div class="doc_text">
621
Chris Lattnere18b32e2008-11-10 05:40:34 +0000[diff] [blame]622<p>This section contains significant known problems with the LLVM system,
623listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]624href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]625there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]626
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]627</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]628
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]629<!-- ======================================================================= -->
630<div class="doc_subsection">
631 <a name="experimental">Experimental features included with this release</a>
632</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]633
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]634<div class="doc_text">
635
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]636<p>The following components of this LLVM release are either untested, known to
637be broken or unreliable, or are in early development. These components should
638not be relied on, and bugs should not be filed against them, but they may be
639useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]640components, please contact us on the <a
641href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]642
643<ul>
Gabor Greifa8b84902008-10-14 11:31:14 +0000[diff] [blame]644<li>The MSIL, IA64, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]645<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]646 value for this option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]647</ul>
648
649</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]650
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]651<!-- ======================================================================= -->
652<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]653 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]654</div>
655
656<div class="doc_text">
657
658<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]659 <li>The X86 backend does not yet support
660 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
661 floating point stack</a>. It supports the 'f' and 't' constraints, but not
662 'u'.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]663 <li>The X86 backend generates inefficient floating point code when configured
664 to generate code for systems that don't have SSE2.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]665 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]666 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
667 currently due
668 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattner04af7cb2008-06-08 23:12:47 +0000[diff] [blame]669 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
670 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]671 <li>The X86-64 backend does not yet support the LLVM IR instruction
672 <tt>va_arg</tt>. Currently, the llvm-gcc front-end supports variadic
673 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]674</ul>
675
676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
680 <a name="ppc-be">Known problems with the PowerPC back-end</a>
681</div>
682
683<div class="doc_text">
684
685<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]686<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]687compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]688</ul>
689
690</div>
691
692<!-- ======================================================================= -->
693<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]694 <a name="arm-be">Known problems with the ARM back-end</a>
695</div>
696
697<div class="doc_text">
698
699<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]700<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]701processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]702results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]703<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
704</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]705<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
706 execute
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]707programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]708</ul>
709
710</div>
711
712<!-- ======================================================================= -->
713<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]714 <a name="sparc-be">Known problems with the SPARC back-end</a>
715</div>
716
717<div class="doc_text">
718
719<ul>
720<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
721 support the 64-bit SPARC ABI (-m64).</li>
722</ul>
723
724</div>
725
726<!-- ======================================================================= -->
727<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]728 <a name="mips-be">Known problems with the MIPS back-end</a>
729</div>
730
731<div class="doc_text">
732
733<ul>
734<li>The O32 ABI is not fully supported.</li>
735<li>64-bit MIPS targets are not supported yet.</li>
736</ul>
737
738</div>
739
740<!-- ======================================================================= -->
741<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]742 <a name="alpha-be">Known problems with the Alpha back-end</a>
743</div>
744
745<div class="doc_text">
746
747<ul>
748
749<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
750appropriate nops inserted to ensure restartability.</li>
751
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]752</ul>
753</div>
754
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]755<!-- ======================================================================= -->
756<div class="doc_subsection">
757 <a name="ia64-be">Known problems with the IA64 back-end</a>
758</div>
759
760<div class="doc_text">
761
762<ul>
Chris Lattner04af7cb2008-06-08 23:12:47 +0000[diff] [blame]763<li>The Itanium backend is highly experimental, and has a number of known
764 issues. We are looking for a maintainer for the Itanium backend. If you
Gabor Greif3bd3a262008-10-15 10:47:24 +0000[diff] [blame]765 are interested, please contact the LLVMdev mailing list.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]766</ul>
767
768</div>
769
770<!-- ======================================================================= -->
771<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]772 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]773</div>
774
775<div class="doc_text">
776
777<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]778<li><a href="http://llvm.org/PR802">The C backend has only basic support for
779 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]780<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
781 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]782 C++ code compiled with llc or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]783<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000[diff] [blame]784<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]785</ul>
786
787</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]788
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]789
790<!-- ======================================================================= -->
791<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]792 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]793</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]794
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]795<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]796
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]797<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
798Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Gabor Greif3bd3a262008-10-15 10:47:24 +0000[diff] [blame]799LLVMdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]800
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]801<p>The only major language feature of GCC not supported by llvm-gcc is
802 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
803 are only supported on some targets. For example, trampolines are only
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]804 supported on some targets (these are used when you take the address of a
805 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]806
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]807<p>If you run into GCC extensions which are not supported, please let us know.
808</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]809
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]810</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]811
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]812<!-- ======================================================================= -->
813<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]814 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]815</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]816
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]817<div class="doc_text">
818
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]819<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]820tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]821itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]822
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]823<ul>
Anton Korobeynikov0021fc12008-10-11 18:27:16 +0000[diff] [blame]824<li>Exception handling works well on the X86 and PowerPC targets. Currently
Chris Lattnere18b32e2008-11-10 05:40:34 +0000[diff] [blame]825 only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]826</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]827
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]828</div>
829
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]830<!-- ======================================================================= -->
831<div class="doc_subsection">
832 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
833</div>
834
835<div class="doc_text">
Gabor Greifba10fe02008-11-04 21:50:59 +0000[diff] [blame]836<ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]837<li>Fortran support generally works, but there are still several unresolved bugs
838 in Bugzilla. Please see the tools/gfortran component for details.</li>
839
840<li>The Fortran front-end currently does not build on Darwin (without tweaks)
841 due to unresolved dependencies on the C front-end.</li>
Gabor Greifba10fe02008-11-04 21:50:59 +0000[diff] [blame]842</ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]843</div>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]844
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]845<!-- ======================================================================= -->
846<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]847 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]848</div>
849
850<div class="doc_text">
851The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
852technology and problems should be expected.
853<ul>
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]854<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]855to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]856however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]857which does support trampolines.</li>
858<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sands326a4982009-02-25 11:59:06 +0000[diff] [blame]859This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
860exception handling, which is used internally by the compiler.
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]861Workaround: configure with --disable-bootstrap.</li>
Duncan Sands978bcee2008-10-13 17:27:23 +0000[diff] [blame]862<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
863and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sands326a4982009-02-25 11:59:06 +0000[diff] [blame]864(c380004 also fails with gcc-4.2 mainline).
865If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
866causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sands978bcee2008-10-13 17:27:23 +0000[diff] [blame]867<li>Some gcc specific Ada tests continue to crash the compiler.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]868<li>The -E binder option (exception backtraces)
869<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
870crashing if an exception is raised. Workaround: do not use -E.</li>
871<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
872or finish at a non-byte offset</a> in a record. Workaround: do not pack records
873or use representation clauses that result in a field of a non-discrete type
874starting or finishing in the middle of a byte.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]875<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
876'main' as generated by the Ada binder to be invalid</a>.
877Workaround: hand edit the file to use pointers for <tt>argv</tt> and
878<tt>envp</tt> rather than integers.</li>
879<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
880ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]881</ul>
882</div>
883
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]884<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]885<div class="doc_section">
886 <a name="additionalinfo">Additional Information</a>
887</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]888<!-- *********************************************************************** -->
889
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]890<div class="doc_text">
891
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]892<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]893href="http://llvm.org">LLVM web page</a>, in particular in the <a
894href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]895contains versions of the API documentation which is up-to-date with the
896Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]897You can access versions of these documents specific to this release by going
898into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]899
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]900<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]901us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]902lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]903
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]904</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]905
906<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]907
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]908<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]909<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]910 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]911 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]912 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]913 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]914
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]915 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]916 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]917</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]918
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]919</body>
920</html>