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Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]7 <title>LLVM 2.5 Release Notes</title>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8</head>
9<body>
10
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]11<div class="doc_title">LLVM 2.5 Release Notes</div>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]12
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]13<ol>
14 <li><a href="#intro">Introduction</a></li>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]15 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]16 <li><a href="#externalproj">External Projects Using LLVM 2.5</a></li>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]17 <li><a href="#whatsnew">What's New in LLVM?</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]18 <li><a href="GettingStarted.html">Installation Instructions</a></li>
19 <li><a href="#portability">Portability and Supported Platforms</a></li>
Dan Gohman0de549c2008-10-14 16:23:02 +0000[diff] [blame]20 <li><a href="#knownproblems">Known Problems</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]21 <li><a href="#additionalinfo">Additional Information</a></li>
22</ol>
23
24<div class="doc_author">
Dan Gohman0de549c2008-10-14 16:23:02 +0000[diff] [blame]25 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]26</div>
27
28<!-- *********************************************************************** -->
29<div class="doc_section">
30 <a name="intro">Introduction</a>
31</div>
32<!-- *********************************************************************** -->
33
34<div class="doc_text">
35
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]36<p>This document contains the release notes for the LLVM Compiler
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]37Infrastructure, release 2.5. Here we describe the status of LLVM, including
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]38major improvements from the previous release and significant known problems.
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]39All LLVM releases may be downloaded from the <a
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]40href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]41
42<p>For more information about LLVM, including information about the latest
43release, please check out the <a href="http://llvm.org/">main LLVM
44web site</a>. If you have questions or comments, the <a
Chris Lattner92eacf82008-10-13 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]47
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]48<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]49main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif7c65c4f2008-10-14 11:00:32 +0000[diff] [blame]50current one. To see the release notes for a specific release, please see the
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]51<a href="http://llvm.org/releases/">releases page</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]52
53</div>
54
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]55<!-- Unfinished features in 2.5:
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]56 Machine LICM
57 Machine Sinking
Chris Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]58 target-specific intrinsics
59 gold lto plugin
Chris Lattner56b64702009-02-25 07:32:53 +0000[diff] [blame]60 pre-alloc splitter, strong phi elim
Chris Lattner4f076402008-10-12 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 Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]63 debug info for optimized code
Chris Lattner5c109932009-02-26 07:29:17 +0000[diff] [blame]64 interpreter + libffi
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]65 postalloc scheduler: anti dependence breaking, hazard recognizer?
66
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]67 -->
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]68
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]69 <!-- for announcement email:
Chris Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]70 -->
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]71
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]72<!-- *********************************************************************** -->
73<div class="doc_section">
74 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]75</div>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]76<!-- *********************************************************************** -->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]77
78<div class="doc_text">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]79<p>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]80The LLVM 2.5 distribution currently consists of code from the core LLVM
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]81repository (which roughly includes the LLVM optimizers, code generators and
Chris Lattnerf6a0d382008-06-08 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 Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]84are the most actively developed are the <a href="#clang">Clang Project</a> and
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]85the <a href="#vmkit">VMKit Project</a>.
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]86</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]87
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]88</div>
89
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]90
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]91<!--=========================================================================-->
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]92<div class="doc_subsection">
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]93<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerf6a0d382008-06-08 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
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]100and code generator. While Clang is not included in the LLVM 2.5 release, it
Chris Lattnerc97507b2009-02-25 05:09:54 +0000[diff] [blame]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 Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]104including <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">the FreeBSD
105kernel</a>. C++ is also making <a
Chris Lattnerc97507b2009-02-25 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 Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]108
Chris Lattnerc97507b2009-02-25 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 Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]112by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]113and reporting any issues you hit to the <a
Chris Lattnerc97507b2009-02-25 05:09:54 +0000[diff] [blame]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 Wendling385b0d32008-10-27 09:27:33 +0000[diff] [blame]118
Daniel Dunbarf3e35782008-10-14 23:25:09 +0000[diff] [blame]119<ul>
Chris Lattnerc97507b2009-02-25 05:09:54 +0000[diff] [blame]120<li>Clang now has a new driver, which is focused on providing a GCC-compatible
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]121 interface.</li>
122<li>The X86-64 ABI is now supported.</li>
123<li>Precompiled header support is now implemented.</li>
Chris Lattnerc97507b2009-02-25 05:09:54 +0000[diff] [blame]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 Lattnera3c683b2008-10-13 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 Kremeneka0d77d72009-02-27 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 Lattnerc2d84672008-10-14 00:52:49 +0000[diff] [blame]141
Ted Kremeneka0d77d72009-02-27 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 Kremenek0437b2c2008-10-14 05:14:21 +0000[diff] [blame]149
Ted Kremeneka0d77d72009-02-27 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 Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]155
156</div>
157
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]158<!--=========================================================================-->
159<div class="doc_subsection">
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]160<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]161</div>
162
163<div class="doc_text">
164<p>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]165The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner78a130b2008-10-13 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 Lattner02408742009-02-25 05:45:05 +0000[diff] [blame]169<p>Following LLVM 2.5, VMKit has its first release ? that you can find on its
Nicolas Geoffray20cfdd42008-10-15 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 Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]172
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]173<ul>
174
Chris Lattner47bcf612009-02-26 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 Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]188
189</ul>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]190</div>
191
Chris Lattnerb2cc5022009-02-26 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,
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]212lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]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 Lattner1ad599a2009-02-28 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 Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]261
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]262
263<!-- *********************************************************************** -->
264<div class="doc_section">
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]265 <a name="whatsnew">What's New in LLVM?</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]266</div>
267<!-- *********************************************************************** -->
268
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]269<div class="doc_text">
270
Bill Wendling385b0d32008-10-27 09:27:33 +0000[diff] [blame]271<p>This release includes a huge number of bug fixes, performance tweaks, and
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]272minor improvements. Some of the major improvements and new features are listed
273in this section.
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]274</p>
275</div>
276
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]277<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]278<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]279<a name="majorfeatures">Major New Features</a>
280</div>
281
282<div class="doc_text">
283
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]284<p>LLVM 2.5 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]285
286<ul>
Duncan Sandse2cd8182009-02-25 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 Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]296
297<!--
298Random stuff:
299
Chris Lattner5c109932009-02-26 07:29:17 +0000[diff] [blame]300Pure project: http://code.google.com/p/pure-lang/
301
302
Chris Lattner56b64702009-02-25 07:32:53 +0000[diff] [blame]303xcore backend!
304fortran on darwin!
305
Chris Lattner5c109932009-02-26 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 Lattnera79cc152009-02-26 06:47:09 +0000[diff] [blame]308GCC inliner off, llvm handles always-inline.
Chris Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]309cmake mature?
Chris Lattner5c109932009-02-26 07:29:17 +0000[diff] [blame]310x86 backend GS segment -> addr space 256 (r62980)
Chris Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]311nocapture
Duncan Sands942eece2009-03-01 08:26:19 +0000[diff] [blame]312addreadattrs pass renamed to functionattrs; now calculates nocapture
Chris Lattnera79cc152009-02-26 06:47:09 +0000[diff] [blame]313memdep (used by GVN and memcpyopt) is faster / more aggressive.
Chris Lattner56b64702009-02-25 07:32:53 +0000[diff] [blame]314how to write a backend doc docs/WritingAnLLVMBackend.html
Chris Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]315fastisel + exception handling
316vector widening <3 x float> -> <4 x float>
Chris Lattner56b64702009-02-25 07:32:53 +0000[diff] [blame]317arm port improvements? arm jit encoding stuff, constant island support?
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]318JIT TLS support on x86-32 but not x86-64.
Chris Lattner56b64702009-02-25 07:32:53 +0000[diff] [blame]319mem2reg now faster on code with huge basic blocks
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]320stack protectors/stack canaries, -fstack-protector, controllable on a
Chris Lattner56b64702009-02-25 07:32:53 +0000[diff] [blame]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 Lattner5c109932009-02-26 07:29:17 +0000[diff] [blame]326 DebugInfoBuilder gone.
Chris Lattner56b64702009-02-25 07:32:53 +0000[diff] [blame]327asmprinters seperate from targets for jits
Chris Lattner47bcf612009-02-26 05:20:36 +0000[diff] [blame]328PBQP register allocator now supports register coalescing.
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]329JIT supports exceptions on linux/x86-64 and linux/x86-64.
Chris Lattnera79cc152009-02-26 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 Lattnera79cc152009-02-26 06:47:09 +0000[diff] [blame]335Jump threading more powerful: it is iterative, handles threading based on values
336 with fully redundant and partially redundant loads.
337LSR improvements?
338ARM debug info support?
339unit test framework based on Google Test.
340
341vector shift support + X86 backend.
Chris Lattner5c109932009-02-26 07:29:17 +0000[diff] [blame]342x86 JIT now detects core i7 and atom, autoconfiguring itself appropriately.
343SROA is more aggressive about promoting unions.
344non-zero __builtin_return_address values on X86.
345x86-64 now uses red zone (unless -mno-red-zone option is specified).
346private linkage.
Chris Lattner47bcf612009-02-26 05:20:36 +0000[diff] [blame]347
Chris Lattner5c109932009-02-26 07:29:17 +0000[diff] [blame]348llvm-gcc defaults to -fno-math-errno on all x86 targets.
349
350initial support for debug line numbers when optimization enabled, not useful in
351 2.5 but will be for 2.6.
Chris Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]352-->
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]353
Chris Lattner5ba16862008-02-10 08:18:42 +0000[diff] [blame]354</ul>
355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]356</div>
357
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]358
359<!--=========================================================================-->
360<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]361<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]362</div>
363
364<div class="doc_text">
365
Chris Lattner4352cc82008-10-13 20:47:20 +0000[diff] [blame]366<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC
367front-ends and driver with the LLVM optimizer and code generator. It currently
368includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]369
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]370<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]371<li>?</li>
Gabor Greif0e49cc82008-06-09 06:06:18 +0000[diff] [blame]372</ul>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]373
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]374</div>
375
376
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]377<!--=========================================================================-->
378<div class="doc_subsection">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]379<a name="coreimprovements">LLVM Core Improvements</a>
380</div>
381
382<div class="doc_text">
Bill Wendling385b0d32008-10-27 09:27:33 +0000[diff] [blame]383<p>New features include:</p>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]384
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]385<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]386<li>?</li>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]387
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]388</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]389
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]390</div>
391
392<!--=========================================================================-->
393<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]394<a name="optimizer">Optimizer Improvements</a>
395</div>
396
397<div class="doc_text">
398
Chris Lattnerea9c2242008-10-13 21:50:36 +0000[diff] [blame]399<p>In addition to a huge array of bug fixes and minor performance tweaks, this
400release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]401
402<ul>
403
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]404<li>?</li>
Chris Lattnerea9c2242008-10-13 21:50:36 +0000[diff] [blame]405
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]406</ul>
407
408</div>
409
410<!--=========================================================================-->
411<div class="doc_subsection">
412<a name="codegen">Code Generator Improvements</a>
413</div>
414
415<div class="doc_text">
416
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]417<p>We have put a significant amount of work into the code generator
418infrastructure, which allows us to implement more aggressive algorithms and make
419it run faster:</p>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]420
421<ul>
Duncan Sands335d5e42009-02-25 11:50:08 +0000[diff] [blame]422<li>The type legalization logic has been completely rewritten, and is now
423more powerful (it supports arbitrary precision integer types for example)
424and hopefully more correct.
425The type legalizer converts operations on types that are not natively
426supported by the target machine into equivalent code sequences that only use
427natively supported types.
428The old type legalizer is still available and will be used if
429<tt>-disable-legalize-types</tt> is passed to <tt>llc</tt>.
430</li>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]431<li>?</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]432
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]433</ul>
434
435</div>
436
437
438<!--=========================================================================-->
439<div class="doc_subsection">
Chris Lattnere1fbd752009-02-26 07:32:11 +0000[diff] [blame]440<a name="pic16">PIC16 Target Improvements</a>
441</div>
442
443<div class="doc_text">
444<p>New features of the PIC16 target include:
445</p>
446
447<ul>
448<li>Both direct and indirect load/stores work now.</li>
449<li>Logical, bitwise and conditional operations now work for integer data
450types.</li>
451<li>Function calls involving basic types work now.</li>
452<li>Support for integer arrays.</li>
453<li>Compiler can now emit libcalls for operations not support by m/c insns.</li>
454<li>Support for both data and rom address spaces.</li>
455</li>
456</ul>
457
458<p>Things not yet supported:</p>
459
460<ul>
461<li>Floating point.</li>
462<li>Passing/returning aggregate types to/from functions.</li>
463<li>Variable arguments.</li>
464<li>Indirect function calls.</li>
465<li>Interrupts/prgrams.</li>
466<li>Debug info.</li>
467</li>
468</ul>
469
470</div>
471
472
473<!--=========================================================================-->
474<div class="doc_subsection">
475<a name="othertargetspecific">Other Target Specific Improvements</a>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]476</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]477
478<div class="doc_text">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]479<p>New target-specific features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]480</p>
481
482<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]483<li>?</li>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]484</ul>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]485
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]486</div>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]487
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]488<!--=========================================================================-->
489<div class="doc_subsection">
490<a name="llvmc">Improvements in LLVMC</a>
491</div>
492
493<div class="doc_text">
494<p>New features include:</p>
495
496<ul>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]497<li>Beginning with LLVM 2.5, <tt>llvmc2</tt> is known as
498 just <tt>llvmc</tt>. The old <tt>llvmc</tt> driver was removed.</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]499
500<li>The Clang plugin was substantially improved and is now enabled
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]501 by default. The command <tt>llvmc --clang</tt> can be now used as a
502 synonym to <tt>ccc</tt>.</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]503
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]504<li>There is now a <tt>--check-graph</tt> option which is supposed to catch
505 common errors like multiple default edges, mismatched output/input language
506 names and cycles. In general, these checks can't be done at compile-time
507 because of the need to support plugins.</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]508
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]509<li>Plugins are now more flexible and can refer to compilation graph nodes and
510 options defined in other plugins. To manage dependencies, a priority-sorting
511 mechanism was introduced. This change affects the TableGen file syntax; see the
512 documentation for details.</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]513
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]514<li>Hooks can now be provided with arguments. The syntax is "<tt>$CALL(MyHook,
515 'Arg1', 'Arg2', 'Arg #3')</tt>".</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]516
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]517<li>A new option type: multi-valued option, for options that take more than one
518 argument (for example, "<tt>-foo a b c</tt>").</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]519
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]520<li>New option properties: '<tt>one_or_more</tt>', '<tt>zero_or_more</tt>',
521'<tt>hidden</tt>' and '<tt>really_hidden</tt>'.</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]522
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]523<li>The '<tt>case</tt>' expression gained an '<tt>error</tt>' action and
524 an '<tt>empty</tt>' test (equivalent to "<tt>(not (not_empty ...))</tt>").</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]525
526<li>Documentation now looks more consistent to the rest of the LLVM
527 docs. There is also a man page now.</li>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]528
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]529</ul>
530
531</div>
532
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]533
534<!--=========================================================================-->
535<div class="doc_subsection">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]536<a name="otherimprovements">Other Improvements</a>
537</div>
538
539<div class="doc_text">
540<p>New features include:
541</p>
542
543<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]544<li>?</li>
Tanya Lattnerc79f7542008-11-04 18:40:27 +0000[diff] [blame]545
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]546</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]547
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]548</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]549
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]550<!--=========================================================================-->
551<div class="doc_subsection">
552<a name="changes">Major Changes and Removed Features</a>
553</div>
554
555<div class="doc_text">
556
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]557<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]558on LLVM 2.4, this section lists some "gotchas" that you may run into upgrading
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]559from the previous release.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]560
561<ul>
562
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]563<li>?</li>
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]564</ul>
565
566
567<p>In addition, many APIs have changed in this release. Some of the major LLVM
568API changes are:</p>
569
570<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]571<li>?</li>
Devang Patel0e3da1a2008-10-14 20:03:43 +0000[diff] [blame]572</ul>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]573
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]574<li>?</li>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]575</ul>
576
577</div>
578
579
580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]581<!-- *********************************************************************** -->
582<div class="doc_section">
583 <a name="portability">Portability and Supported Platforms</a>
584</div>
585<!-- *********************************************************************** -->
586
587<div class="doc_text">
588
589<p>LLVM is known to work on the following platforms:</p>
590
591<ul>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]592<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000[diff] [blame]593Linux, Fedora Core and FreeBSD (and probably other unix-like systems).</li>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]594<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000[diff] [blame]595and 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]596<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]597<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
598 support is available for native builds with Visual C++).</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]599<li>Sun UltraSPARC workstations running Solaris 10.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]600<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]601<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]602</ul>
603
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]604<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]605to the machine and operating system on which it is built. However, minor
606porting may be required to get LLVM to work on new platforms. We welcome your
607portability patches and reports of successful builds or error messages.</p>
608
609</div>
610
611<!-- *********************************************************************** -->
612<div class="doc_section">
613 <a name="knownproblems">Known Problems</a>
614</div>
615<!-- *********************************************************************** -->
616
617<div class="doc_text">
618
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]619<p>This section contains significant known problems with the LLVM system,
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000[diff] [blame]620listed by component. If you run into a problem, please check the <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]621href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
622there isn't already one.</p>
623
624</div>
625
626<!-- ======================================================================= -->
627<div class="doc_subsection">
628 <a name="experimental">Experimental features included with this release</a>
629</div>
630
631<div class="doc_text">
632
633<p>The following components of this LLVM release are either untested, known to
634be broken or unreliable, or are in early development. These components should
635not be relied on, and bugs should not be filed against them, but they may be
636useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]637components, please contact us on the <a
638href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]639
640<ul>
Gabor Greifaa53e562008-10-14 11:31:14 +0000[diff] [blame]641<li>The MSIL, IA64, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]642<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]643 value for this option.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]644</ul>
645
646</div>
647
648<!-- ======================================================================= -->
649<div class="doc_subsection">
650 <a name="x86-be">Known problems with the X86 back-end</a>
651</div>
652
653<div class="doc_text">
654
655<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]656 <li>The X86 backend does not yet support
657 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
658 floating point stack</a>. It supports the 'f' and 't' constraints, but not
659 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]660 <li>The X86 backend generates inefficient floating point code when configured
661 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000[diff] [blame]662 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]663 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
664 currently due
665 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]666 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
667 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]668 <li>The X86-64 backend does not yet support the LLVM IR instruction
669 <tt>va_arg</tt>. Currently, the llvm-gcc front-end supports variadic
670 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]671</ul>
672
673</div>
674
675<!-- ======================================================================= -->
676<div class="doc_subsection">
677 <a name="ppc-be">Known problems with the PowerPC back-end</a>
678</div>
679
680<div class="doc_text">
681
682<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]683<li>The Linux PPC32/ABI support needs testing for the interpreter and static
684compilation, and lacks support for debug information.</li>
685</ul>
686
687</div>
688
689<!-- ======================================================================= -->
690<div class="doc_subsection">
691 <a name="arm-be">Known problems with the ARM back-end</a>
692</div>
693
694<div class="doc_text">
695
696<ul>
697<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]698processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]699results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
700<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
701</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]702<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
703 execute
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]704programs compiled with LLVM. Please use more recent versions of QEMU.</li>
705</ul>
706
707</div>
708
709<!-- ======================================================================= -->
710<div class="doc_subsection">
711 <a name="sparc-be">Known problems with the SPARC back-end</a>
712</div>
713
714<div class="doc_text">
715
716<ul>
717<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
718 support the 64-bit SPARC ABI (-m64).</li>
719</ul>
720
721</div>
722
723<!-- ======================================================================= -->
724<div class="doc_subsection">
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000[diff] [blame]725 <a name="mips-be">Known problems with the MIPS back-end</a>
726</div>
727
728<div class="doc_text">
729
730<ul>
731<li>The O32 ABI is not fully supported.</li>
732<li>64-bit MIPS targets are not supported yet.</li>
733</ul>
734
735</div>
736
737<!-- ======================================================================= -->
738<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]739 <a name="alpha-be">Known problems with the Alpha back-end</a>
740</div>
741
742<div class="doc_text">
743
744<ul>
745
746<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
747appropriate nops inserted to ensure restartability.</li>
748
749</ul>
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
754 <a name="ia64-be">Known problems with the IA64 back-end</a>
755</div>
756
757<div class="doc_text">
758
759<ul>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]760<li>The Itanium backend is highly experimental, and has a number of known
761 issues. We are looking for a maintainer for the Itanium backend. If you
Gabor Greif45fc8b12008-10-15 10:47:24 +0000[diff] [blame]762 are interested, please contact the LLVMdev mailing list.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]763</ul>
764
765</div>
766
767<!-- ======================================================================= -->
768<div class="doc_subsection">
769 <a name="c-be">Known problems with the C back-end</a>
770</div>
771
772<div class="doc_text">
773
774<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]775<li><a href="http://llvm.org/PR802">The C backend has only basic support for
776 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]777<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
778 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]779 C++ code compiled with llc or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000[diff] [blame]780<li>The C backend does not support all exception handling constructs.</li>
Duncan Sandse6e264c2009-02-25 11:51:54 +0000[diff] [blame]781<li>The C backend does not support arbitrary precision integers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]782</ul>
783
784</div>
785
786
787<!-- ======================================================================= -->
788<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]789 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]790</div>
791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]792<div class="doc_text">
793
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]794<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
795Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Gabor Greif45fc8b12008-10-15 10:47:24 +0000[diff] [blame]796LLVMdev mailing list if you are interested.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]797
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]798<p>The only major language feature of GCC not supported by llvm-gcc is
799 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
800 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]801 supported on some targets (these are used when you take the address of a
802 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]804<p>If you run into GCC extensions which are not supported, please let us know.
805</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]806
807</div>
808
809<!-- ======================================================================= -->
810<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]811 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]812</div>
813
814<div class="doc_text">
815
816<p>The C++ front-end is considered to be fully
817tested and works for a number of non-trivial programs, including LLVM
818itself, Qt, Mozilla, etc.</p>
819
820<ul>
Anton Korobeynikovd9a17932008-10-11 18:27:16 +0000[diff] [blame]821<li>Exception handling works well on the X86 and PowerPC targets. Currently
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000[diff] [blame]822 only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]823</ul>
824
825</div>
826
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]827<!-- ======================================================================= -->
828<div class="doc_subsection">
829 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
830</div>
831
832<div class="doc_text">
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000[diff] [blame]833<ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]834<li>Fortran support generally works, but there are still several unresolved bugs
835 in Bugzilla. Please see the tools/gfortran component for details.</li>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame^]836
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]837<li>The Fortran front-end currently does not build on Darwin (without tweaks)
838 due to unresolved dependencies on the C front-end.</li>
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000[diff] [blame]839</ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]840</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]841
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]842<!-- ======================================================================= -->
843<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]844 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]845</div>
846
847<div class="doc_text">
848The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
849technology and problems should be expected.
850<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]851<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]852to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]853however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]854which does support trampolines.</li>
855<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sandsf73473e2009-02-25 11:59:06 +0000[diff] [blame]856This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
857exception handling, which is used internally by the compiler.
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]858Workaround: configure with --disable-bootstrap.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000[diff] [blame]859<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
860and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsf73473e2009-02-25 11:59:06 +0000[diff] [blame]861(c380004 also fails with gcc-4.2 mainline).
862If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
863causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000[diff] [blame]864<li>Some gcc specific Ada tests continue to crash the compiler.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]865<li>The -E binder option (exception backtraces)
866<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
867crashing if an exception is raised. Workaround: do not use -E.</li>
868<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
869or finish at a non-byte offset</a> in a record. Workaround: do not pack records
870or use representation clauses that result in a field of a non-discrete type
871starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]872<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
873'main' as generated by the Ada binder to be invalid</a>.
874Workaround: hand edit the file to use pointers for <tt>argv</tt> and
875<tt>envp</tt> rather than integers.</li>
876<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
877ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]878</ul>
879</div>
880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]881<!-- *********************************************************************** -->
882<div class="doc_section">
883 <a name="additionalinfo">Additional Information</a>
884</div>
885<!-- *********************************************************************** -->
886
887<div class="doc_text">
888
889<p>A wide variety of additional information is available on the <a
890href="http://llvm.org">LLVM web page</a>, in particular in the <a
891href="http://llvm.org/docs/">documentation</a> section. The web page also
892contains versions of the API documentation which is up-to-date with the
893Subversion version of the source code.
894You can access versions of these documents specific to this release by going
895into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
896
897<p>If you have any questions or comments about LLVM, please feel free to contact
898us via the <a href="http://llvm.org/docs/#maillist"> mailing
899lists</a>.</p>
900
901</div>
902
903<!-- *********************************************************************** -->
904
905<hr>
906<address>
907 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]911
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