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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.
39All LLVM releases may be downloaded from the <a
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
Chris Lattnerc97507b2009-02-25 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 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>
Chris Lattnerc97507b2009-02-25 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 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
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 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,
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 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
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 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]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 Lattner5c109932009-02-26 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 Lattner47bcf612009-02-26 05:20:36 +0000[diff] [blame]348
Chris Lattner5c109932009-02-26 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 Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]353-->
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]354
Chris Lattner5ba16862008-02-10 08:18:42 +0000[diff] [blame]355</ul>
356
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]357</div>
358
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]359
360<!--=========================================================================-->
361<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]362<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]363</div>
364
365<div class="doc_text">
366
Chris Lattner4352cc82008-10-13 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 Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]370
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]371<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]372<li>?</li>
Gabor Greif0e49cc82008-06-09 06:06:18 +0000[diff] [blame]373</ul>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]374
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]375</div>
376
377
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]378<!--=========================================================================-->
379<div class="doc_subsection">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]380<a name="coreimprovements">LLVM Core Improvements</a>
381</div>
382
383<div class="doc_text">
Bill Wendling385b0d32008-10-27 09:27:33 +0000[diff] [blame]384<p>New features include:</p>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]385
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]386<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]387<li>?</li>
Chris Lattnerf7bae6d2008-10-13 20:59:32 +0000[diff] [blame]388
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]389</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]390
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]391</div>
392
393<!--=========================================================================-->
394<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]395<a name="optimizer">Optimizer Improvements</a>
396</div>
397
398<div class="doc_text">
399
Chris Lattnerea9c2242008-10-13 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 Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]402
403<ul>
404
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]405<li>?</li>
Chris Lattnerea9c2242008-10-13 21:50:36 +0000[diff] [blame]406
Chris Lattner0eef6e42008-06-08 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 Greifaa53e562008-10-14 11:31:14 +0000[diff] [blame]418<p>We have put a significant amount of work into the code generator infrastructure,
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]419which allows us to implement more aggressive algorithms and make it run
420faster:</p>
421
422<ul>
Duncan Sands335d5e42009-02-25 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 Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]432<li>?</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]433
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]434</ul>
435
436</div>
437
438
439<!--=========================================================================-->
440<div class="doc_subsection">
Chris Lattnere1fbd752009-02-26 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 Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]477</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]478
479<div class="doc_text">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]480<p>New target-specific features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]481</p>
482
483<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]484<li>?</li>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]485</ul>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]486
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]487</div>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]488
Chris Lattner7ccc40d2009-03-01 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 Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]536
537<!--=========================================================================-->
538<div class="doc_subsection">
Chris Lattnerb0d6c502007-09-21 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 Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]547<li>?</li>
Tanya Lattnerc79f7542008-11-04 18:40:27 +0000[diff] [blame]548
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]549</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]550
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]551</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]552
Chris Lattner92eacf82008-10-13 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 Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]560<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]561on LLVM 2.4, this section lists some "gotchas" that you may run into upgrading
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]562from the previous release.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]563
564<ul>
565
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]566<li>?</li>
Chris Lattnercc64a322008-10-13 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 Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]574<li>?</li>
Devang Patel0e3da1a2008-10-14 20:03:43 +0000[diff] [blame]575</ul>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]576
Chris Lattner95d25072009-02-25 04:41:31 +0000[diff] [blame]577<li>?</li>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]578</ul>
579
580</div>
581
582
583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]584<!-- *********************************************************************** -->
585<div class="doc_section">
586 <a name="portability">Portability and Supported Platforms</a>
587</div>
588<!-- *********************************************************************** -->
589
590<div class="doc_text">
591
592<p>LLVM is known to work on the following platforms:</p>
593
594<ul>
Chris Lattnerb1ad47c2008-11-10 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 Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]599<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +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 Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]602<li>Sun UltraSPARC workstations running Solaris 10.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]603<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]604<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]605</ul>
606
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]607<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +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>
611
612</div>
613
614<!-- *********************************************************************** -->
615<div class="doc_section">
616 <a name="knownproblems">Known Problems</a>
617</div>
618<!-- *********************************************************************** -->
619
620<div class="doc_text">
621
Chris Lattnerb1ad47c2008-11-10 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
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]624href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
625there isn't already one.</p>
626
627</div>
628
629<!-- ======================================================================= -->
630<div class="doc_subsection">
631 <a name="experimental">Experimental features included with this release</a>
632</div>
633
634<div class="doc_text">
635
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 Lattnerdaeb3232008-02-12 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]642
643<ul>
Gabor Greifaa53e562008-10-14 11:31:14 +0000[diff] [blame]644<li>The MSIL, IA64, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]645<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]646 value for this option.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]647</ul>
648
649</div>
650
651<!-- ======================================================================= -->
652<div class="doc_subsection">
653 <a name="x86-be">Known problems with the X86 back-end</a>
654</div>
655
656<div class="doc_text">
657
658<ul>
Anton Korobeynikov77d15e22008-06-08 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 Lattnerd95b5962008-06-08 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 Sands8b4f3772008-06-08 19:38:43 +0000[diff] [blame]665 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov77d15e22008-06-08 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 Lattnerf06141a2008-06-08 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 Gohman3882ecb2008-06-08 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]686<li>The Linux PPC32/ABI support needs testing for the interpreter and static
687compilation, and lacks support for debug information.</li>
688</ul>
689
690</div>
691
692<!-- ======================================================================= -->
693<div class="doc_subsection">
694 <a name="arm-be">Known problems with the ARM back-end</a>
695</div>
696
697<div class="doc_text">
698
699<ul>
700<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]701processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]702results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
703<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
704</li>
Chris Lattnerd95b5962008-06-08 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
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]707programs compiled with LLVM. Please use more recent versions of QEMU.</li>
708</ul>
709
710</div>
711
712<!-- ======================================================================= -->
713<div class="doc_subsection">
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 Lopes62d45d72008-10-25 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">
Dan Gohmanf17a25c2007-07-18 16:29:46 +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
752</ul>
753</div>
754
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 Lattnerf06141a2008-06-08 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 Greif45fc8b12008-10-15 10:47:24 +0000[diff] [blame]765 are interested, please contact the LLVMdev mailing list.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]766</ul>
767
768</div>
769
770<!-- ======================================================================= -->
771<div class="doc_subsection">
772 <a name="c-be">Known problems with the C back-end</a>
773</div>
774
775<div class="doc_text">
776
777<ul>
Chris Lattner499c07c2008-06-05 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 Lattnere0194462007-09-26 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 Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]782 C++ code compiled with llc or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000[diff] [blame]783<li>The C backend does not support all exception handling constructs.</li>
Duncan Sandse6e264c2009-02-25 11:51:54 +0000[diff] [blame]784<li>The C backend does not support arbitrary precision integers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]785</ul>
786
787</div>
788
789
790<!-- ======================================================================= -->
791<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]792 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]793</div>
794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]795<div class="doc_text">
796
Chris Lattnere0798082008-02-06 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 Greif45fc8b12008-10-15 10:47:24 +0000[diff] [blame]799LLVMdev mailing list if you are interested.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]800
Chris Lattner499c07c2008-06-05 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 Sandsa73561c2008-06-08 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]806
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]807<p>If you run into GCC extensions which are not supported, please let us know.
808</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]809
810</div>
811
812<!-- ======================================================================= -->
813<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]814 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]815</div>
816
817<div class="doc_text">
818
819<p>The C++ front-end is considered to be fully
820tested and works for a number of non-trivial programs, including LLVM
821itself, Qt, Mozilla, etc.</p>
822
823<ul>
Anton Korobeynikovd9a17932008-10-11 18:27:16 +0000[diff] [blame]824<li>Exception handling works well on the X86 and PowerPC targets. Currently
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000[diff] [blame]825 only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]826</ul>
827
828</div>
829
Chris Lattner6c8a1b82008-10-30 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 Greif1fc8fbc2008-11-04 21:50:59 +0000[diff] [blame]836<ul>
Chris Lattner6c8a1b82008-10-30 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 Greif1fc8fbc2008-11-04 21:50:59 +0000[diff] [blame]842</ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]843</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]844
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]845<!-- ======================================================================= -->
846<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]847 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 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 Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]854<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]855to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]856however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 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 Sandsf73473e2009-02-25 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 Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]861Workaround: configure with --disable-bootstrap.</li>
Duncan Sands2dbc2e82008-10-13 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 Sandsf73473e2009-02-25 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 Sands2dbc2e82008-10-13 17:27:23 +0000[diff] [blame]867<li>Some gcc specific Ada tests continue to crash the compiler.</li>
Chris Lattnerdaeb3232008-02-12 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 Lattnerd95b5962008-06-08 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 Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]881</ul>
882</div>
883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884<!-- *********************************************************************** -->
885<div class="doc_section">
886 <a name="additionalinfo">Additional Information</a>
887</div>
888<!-- *********************************************************************** -->
889
890<div class="doc_text">
891
892<p>A wide variety of additional information is available on the <a
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
895contains versions of the API documentation which is up-to-date with the
896Subversion version of the source code.
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>
899
900<p>If you have any questions or comments about LLVM, please feel free to contact
901us via the <a href="http://llvm.org/docs/#maillist"> mailing
902lists</a>.</p>
903
904</div>
905
906<!-- *********************************************************************** -->
907
908<hr>
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