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Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]7 <title>LLVM 2.0 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]10
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]11<div class="doc_title">LLVM 2.0 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]25
26<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
31
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]32<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]35infrastructure, release 2.0. Here we describe the status of LLVM, including any
36known problems and major improvements from the previous release. All LLVM
37releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
38releases web site</a>.
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]39
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]40<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]41release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]42web site</a>. If you have questions or comments, the <a
43href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]44list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]45
Chris Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]46<p>Note that if you are reading this file from CVS or the main LLVM web page,
47this document applies to the <i>next</i> release, not the current one. To see
48the release notes for the current or previous releases, see the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]49href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]50
51</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]52
53<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]54<div class="doc_section">
55 <a name="whatsnew">What's New?</a>
56</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]57<!-- *********************************************************************** -->
58
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]59<div class="doc_text">
60
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]61<p>This is the eleventh public release of the LLVM Compiler Infrastructure.
Chris Lattnerf01b0b52007-05-09 05:27:05 +0000[diff] [blame]62Being the first major release since 1.0, this release is different in several
63ways from our previous releases:</p>
64
65<ol>
66<li>We took this as an opportunity to
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]67break backwards compatibility with the LLVM 1.x bytecode and .ll file format.
68If you have LLVM 1.9 .ll files that you would like to upgrade to LLVM 2.x, we
Lauro Ramos Venanciobe1b1b12007-05-12 02:36:41 +0000[diff] [blame]69recommend the use of the stand alone <a href="#llvm-upgrade">llvm-upgrade</a>
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]70tool. We intend to keep compatibility with .ll and .bc formats within the 2.x
Chris Lattnerf01b0b52007-05-09 05:27:05 +0000[diff] [blame]71release series, like we did within the 1.x series.</li>
72<li>There are several significant change to the LLVM IR and internal APIs, such
73 as a major overhaul of the type system, the completely new bitcode file
74 format, etc.</li>
75<li>We designed the release around a 6 month release cycle instead of the usual
76 3-month cycle. This gave us extra time to develop and test some of the
77 more invasive features in this release.</li>
78<li>LLVM 2.0 no longer supports the llvm-gcc3 front-end.</li>
79</ol>
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]80
Chris Lattnerf01b0b52007-05-09 05:27:05 +0000[diff] [blame]81<p>Note that while this is a major version bump, this release has been
82 extensively tested on a wide range of software. It is easy to say that this
83 is our best release yet, in terms of both features and correctness.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]84
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]85</div>
86
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]87<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]88<div class="doc_subsection">
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]89<a name="newfeatures">New Features in LLVM 2.0</a>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]90</div>
91
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]92<!--_________________________________________________________________________-->
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]93<div class="doc_subsubsection"><a name="majorchanges">Major Changes</a></div>
94<div class="doc_text">
95<p>blah
96</p>
97
98<ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]99
100<li>llvm-gcc3 is now officially unsupported. Users are required to
101 upgrade to llvm-gcc4. llvm-gcc4 includes many features over
102 llvm-gcc3, is faster, and is much easier to build.</li>
103
104<li>Integer types are now completely signless. This means that we
105 have types like i8/i16/i32 instead of ubyte/sbyte/short/ushort/int
106 etc. LLVM operations that depend on sign have been split up into
107 separate instructions (<a href="http://llvm.org/PR950">PR950</a>).</li>
108
109<li>Arbitrary bitwidth integers (e.g. i13, i36, i42, etc) are now
110 supported in the LLVM IR and optimizations. However, neither llvm-gcc nor
111 the native code generators support non-standard width integers
112 (<a href="http://llvm.org/PR1043">PR1043</a>).</li>
113
114<li>'type planes' have been removed (<a href="http://llvm.org/PR411">PR411</a>).
115 It is no longer possible to have two values with the same name in the
116 same symbol table. This simplifies LLVM internals, allowing significant
117 speedups.</li>
118
119<li>Global variables and functions in .ll files are now prefixed with
120 @ instead of % (<a href="http://llvm.org/PR645">PR645</a>).</li>
121
122<li>The LLVM 1.x "bytecode" format has been replaced with a
123 completely new binary representation, named 'bitcode'. Because we
124 plan to maintain binary compatibility between LLVM 2.x ".bc" files,
125 this is an important change to get right. Bitcode brings a number of
126 advantages to the LLVM over the old bytecode format. It is denser
127 (files are smaller), more extensible, requires less memory to read,
128 is easier to keep backwards compatible (so LLVM 2.5 will read 2.0 .bc
129 files), and has many other nice features.</li>
130
131<li>Support was added for alignment values on load and store
132 instructions (<a href="http://www.llvm.org/PR400">PR400</a>). This
133 allows the IR to express loads that are not
134 sufficiently aligned (e.g. due to pragma packed) or to capture extra
135 alignment information. </li>
136
137<li>LLVM now has a new MSIL backend. llc - march=msil will now turn LLVM
138 into MSIL (".net") bytecode. This is still fairly early development
139 with a number of limitations.</li>
140
141<li>Support has been added for 'protected visibility' in ELF.</li>
142
143<li>Thread Local Storage with the __thread keyword was implemented along
144 with added codegen support for Linux on X86 and ARM.</li>
145
146<li>ELF symbol aliases supported has been added.</li>
147
148<li>Added support for 'polymorphic intrinsics', allowing things like
149 llvm.ctpop to work on arbitrary width integers.</li>
150
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]151</ul>
152
153</div>
154
155
156<!--_________________________________________________________________________-->
157<div class="doc_subsubsection"><a name="llvmgccfeatures">llvm-gcc
158Improvements</a></div>
159<div class="doc_text">
160<p>New features include:
161</p>
162
163<ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]164<li>Precompiled Headers (PCH) support has been implemented.</li>
165
166<li>Support for external weak linkage and hidden visibility has been added.</li>
167
168<li>Packed structure types are now supported , which allows LLVM to express
169 unaligned data more naturally.</li>
170
171<li>Inline assembly support has been improved and many bugs were fixed.
172 The two large missing features are support for 80-bit floating point stack
173 registers on X86 (<a href="http://llvm.org/PR879">PR879</a>), and support for inline asm in the C backend (<a href="http://llvm.org/PR802">PR802</a>).</li>
174
175<li>Ada support, such as nested functions, has been improved.</li>
176
177<li>Tracking function parameter/result attributes is now possible.</li>
178
179<li>Its is now easier to configure llvm-gcc for linux.</li>
180
181<li>Many enhancements have been added, such as improvements to NON_LVALUE_EXPR,
182 arrays with non-zero base, structs with variable sized fields,
183 VIEW_CONVERT_EXPR, CEIL_DIV_EXPR, and many other things.</li>
184
185<li>Improved "attribute packed" support in the CFE, and handle many
186 other obscure struct layout cases correctly.</li>
187
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]188</ul>
189
190</div>
191
192<!--_________________________________________________________________________-->
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]193<div class="doc_subsubsection"><a name="optimizer">Optimizer
194Improvements</a></div>
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]195<div class="doc_text">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]196<p>New features include:
197</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]198
199<ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]200<li>The pass manager has been entirely rewritten, making it significantly
201 smaller, simpler, and more extensible. Support has been added to run
202 FunctionPasses interlaced with CallGraphSCCPasses.</li>
203
204<li>The -scalarrepl pass can now promote unions containing FP values into
205 a register, it can also handle unions of vectors of the same size.</li>
206
207<li>The predicate simplifier pass has been improved, making it able to do
208 simple value range propagation and eliminate more conditionals.</li>
209
210<li>There is a new new LoopPass class. The passmanager has been
211 modified to support it, and all existing loop xforms have been
212 converted to use it. </li>
213
214<li>There is a new loop rotation pass, which converts "for loops" into
215 "do/while loops", where the condition is at the bottom of the loop.</li>
216
217<li>ModulePasses may now use the result of FunctionPasses.</li>
218
219<li>The [Post]DominatorSet classes have been removed from LLVM and clients switched to use the far-more-efficient ETForest class instead. </li>
220
221<li>The ImmediateDominator class has also been removed, and clients have been switched to use DominatorTree instead.</li>
222
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]223</ul>
224
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]225</div>
226
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]227<!--_________________________________________________________________________-->
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]228<div class="doc_subsubsection"><a name="codegen">Code
229Generator Enhancements</a></div>
230
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]231<div class="doc_text">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]232<p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]233New features include:
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]234</p>
235
236<ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]237<li>Support for Zero-cost DWARF exception handling has been added. It is mostly
238 complete and just in need of continued bug fixes and optimizations at
239 this point.</li>
240
241<li>Progress has been made on a direct Mach-o .o file writer. Many small
242 apps work, but it is not quite complete yet.</li>
243
244<li>Support was added for software floating point routines.</li>
245
246<li>DWARF debug information generation has been improved. LLVM now passes
247 most of the GDB testsuite on MacOS and debug info is more dense.</li>
248
249<li>A new register scavenger has been implemented, which is useful for
250 finding free registers after register allocation. This is useful when
251 rewriting frame references on RISC targets, for example.</li>
252
253<li>Heuristics have been added to avoid coalescing vregs with very large live
254 ranges to physregs.</li>
255
256<li>Support now exists for very simple (but still very useful)
257 rematerialization the register allocator, enough to move
258 instructions like "load immediate" and constant pool loads.</li>
259
260<li>Significantly improved 'switch' lowering, improving codegen for
261 sparse switches that have dense subregions, and implemented support
262 for the shift/and trick.</li>
263
264<li>The code generator now has more accurate and general hooks for
265 describing addressing modes ("isLegalAddressingMode") to
266 optimizations like loop strength reduction and code sinking.</li>
267
268<li>The Loop Strength Reduction pass has been improved, and support added
269 for sinking expressions across blocks to reduce register pressure.</li>
270
271<li>Added support for tracking physreg sub-registers and super-registers
272 in the code generator, as well as extensive register
273 allocator changes to track them.</li>
274
275<li>There is initial support for virtreg sub-registers
276 (<a href="http://llvm.org/PR1350">PR1350</a>).</li>
277
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]278</ul>
279
280<p>In addition, the LLVM target description format has itself been extended in
281 several ways:</p>
282
283<ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]284<li>Extended TargetData to support better target parameterization in
285 the .ll/.bc files, eliminating the 'pointersize/endianness' attributes
286 in the files (<a href="http://llvm.org/PR761">PR761</a>).</li>
287
288<li>TargetData was generalized for finer grained alignment handling,
289 handling of vector alignment, and handling of preferred alignment</li>
290
291<li>LLVM now supports describing target calling conventions
292 explicitly in .td files, reducing the amount of C++ code that needs
293 to be written for a port.</li>
294
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]295</ul>
296
297<p>Further, several significant target-specific enhancements are included in
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]298LLVM 2.0:</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]299
300<ul>
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]301<li></li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]302</ul>
303
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]304</div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]305
306<!--_________________________________________________________________________-->
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]307<div class="doc_subsubsection"><a name="specifictargets">Target-Specific
308Improvements</a></div>
309
310<div class="doc_text">
311
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]312<p>X86-Specific Code Generator Enhancements:
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]313</p>
314
315<ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]316<li>The scheduler was improved to better reduce register pressure on
317 X86 and other targets that are register pressure sensitive</li>
318<li>Linux/x86-64 support has been improved.</li>
319<li>PIC support for linux/x86 has been added.</li>
320<li>Support now exists for the GCC regparm attribute, and code in the X86
321 backend to respect it.</li>
322<li>Various improvements have been made for the X86-64 JIT, allowing it to
323 generate code in the large code model</li>
324<li>LLVM now supports inline asm with multiple constraint letters per operand
325 (like "ri") which is common in X86 inline asms.</li>
326<li>Early support has been added for X86 inline asm in the C backend.</li>
327<li>Added support for the X86 MMX instruction set.</li>
328
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]329</ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]330
331<p>ARM-Specific Code Generator Enhancements:
332</p>
333
334<ul>
335<li>Several improvements have been made to the ARM backend, including basic
336 inline asm support, weak linkage support, static ctor/dtor support and
337 many bug fixes.</li>
338<li>There are major enhancements to the ARM backend, including support for ARM
339 v4-v6, vfp support, soft float, pre/postinc support, load/store multiple
340 generation, constant pool entry motion (to support large functions),
341 and enhancements to ARM constant island pass.
342 </li>
343<li>Added support for Thumb code generation (an ARM subtarget).</li>
344<li>More aggressive size analysis for ARM inline asm strings was
345 implemented.</li>
346</ul>
347
348</div>
349
350<p>Other Target-Specific Code Generator Enhancements:
351</p>
352
353<ul>
354<li>The PowerPC 64 JIT now supports addressing code loaded above the 2G
355 boundary.</li>
356
357<li>Improved support for the Linux/ppc ABI and the linux/ppc JIT is fully
358 functional now. llvm-gcc and static compilation are not fully supported
359 yet though.<</li>
360
361<li>Many bugs fixed for PowerPC 64.</li>
362
363<li>Support was added for the ARM AAPCS and EABI ABIs and PIC codegen on
364 arm/linux.</li>
365
366<li>Several bugs in DWARF debug emission on linux and cygwin/mingw were fixed.
367 Debugging basically works on these targets now.</li>
368
369<li>Support has been added for the X86-64 large code model to the JIT,
370 which is useful if JIT'd function bodies are more than 2G away from
371 library functions.</li>
372
373<li>Several bugs were fixed for DWARF debug info generation on arm/linux.</li>
374
375</ul>
376
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]377</div>
378
379
380<!--_________________________________________________________________________-->
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]381<div class="doc_subsubsection"><a name="other">Other Improvements</a></div>
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]382<div class="doc_text">
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]383
384<p>This release includes many other improvements, including
385performance work, specifically designed to tune datastructure
386usage. This makes several critical components faster.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]387
388<p>More specific changes include:</p>
389
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]390<ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000[diff] [blame^]391<li>ConstantBool, ConstantIntegral and ConstantInt classes have been merged
392 together, we now just have ConstantInt</li>
393
394<li>LLVM no longer relies on static destructors to shut itself down. Instead,
395 it lazily initializes itself and shuts down when llvm_shutdown() is
396 explicitly called.</li>
397
398<li>LLVM now has significantly fewer static constructors, reducing startup time.
399 </li>
400
401<li>Several classes have been refactored to reduce the amount of code that
402 gets linked into apps that use the JIT.</li>
403
404<li>Construction of intrinsic function declarations has been simplified.</li>
405
406<li>The llvm-upgrade tool now exists. This migrates LLVM 1.9 .ll files to
407 LLVM 2.0 syntax.</li>
408
409<li>The gccas/gccld tools have been removed.</li>
410
411<li>Support has been added to llvm-test for running on low-memory
412 or slow machines (make SMALL_PROBLEM_SIZE=1).</li>
413
414<li>llvm-test is now more portable and should build with MS Visual Studio.</li>
415
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]416</ul>
417</div>
John Criswelle531ec52005-06-29 16:22:34 +0000[diff] [blame]418
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]419
420
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]421<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]422<div class="doc_section">
423 <a name="portability">Portability and Supported Platforms</a>
424</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]425<!-- *********************************************************************** -->
426
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]427<div class="doc_text">
428
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]429<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]430
431<ul>
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]432 <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
433 (and probably other unix-like systems).</li>
Chris Lattner7ea41e32006-08-09 04:10:32 +0000[diff] [blame]434<li>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]435<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]436<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
437 support is available for native builds with Visual C++).</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]438<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above in 32-bit and
439 64-bit modes.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]440<li>Alpha-based machines running Debian GNU/Linux.</li>
441<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]442</ul>
443
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]444<p>The core LLVM infrastructure uses
445<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
446to the machine and operating system on which it is built. However, minor
447porting may be required to get LLVM to work on new platforms. We welcome your
448portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]449
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]450</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]451
452<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]453<div class="doc_section">
454 <a name="knownproblems">Known Problems</a>
455</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]456<!-- *********************************************************************** -->
457
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]458<div class="doc_text">
459
460<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]461component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]462sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]463href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]464there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]465
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]466</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]467
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]468<!-- ======================================================================= -->
469<div class="doc_subsection">
470 <a name="experimental">Experimental features included with this release</a>
471</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]472
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]473<div class="doc_text">
474
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]475<p>The following components of this LLVM release are either untested, known to
476be broken or unreliable, or are in early development. These components should
477not be relied on, and bugs should not be filed against them, but they may be
478useful to some people. In particular, if you would like to work on one of these
Chris Lattner49e693e2006-08-09 04:08:52 +0000[diff] [blame]479components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]480
481<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]482<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
483 future release.</li>
Chris Lattner0d77e052007-05-09 06:23:58 +0000[diff] [blame]484<li>C++ EH support</li>
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]485<li>The IA64 code generator is experimental.</li>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]486<li>The Alpha JIT is experimental.</li>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]487<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
488 <tt>-filetype</tt> llc option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]489</ul>
490
491</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]492
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]493<!-- ======================================================================= -->
494<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]495 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]496</div>
497
498<div class="doc_text">
499
500<ul>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]501<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]502 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]503</ul>
504
505</div>
506
507<!-- ======================================================================= -->
508<div class="doc_subsection">
509 <a name="ppc-be">Known problems with the PowerPC back-end</a>
510</div>
511
512<div class="doc_text">
513
514<ul>
515<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
516implement ordered FP comparisons</a>.</li>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]517<li>The Linux PPC32/ABI support needs testing for the interpreter and static
518compilation, and lacks Dwarf debugging informations.
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]519</ul>
520
521</div>
522
523<!-- ======================================================================= -->
524<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]525 <a name="arm-be">Known problems with the ARM back-end</a>
526</div>
527
528<div class="doc_text">
529
530<ul>
531<li>The Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
532processors, any thumb program compiled with LLVM crashes or produces wrong
533results. (<a href="http://llvm.org/PR1388">PR1388</a>)</li>
534<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
535</li>
536<li>QEMU-ARM (<= 0.9.0) wrongly executes programs compiled with LLVM. A non-affected QEMU version must be used or this
537<a href="http://cvs.savannah.nongnu.org/viewcvs/qemu/target-arm/translate.c?root=qemu&r1=1.46&r2=1.47&makepatch=1&diff_format=h">
538patch</a> must be applied on QEMU.</li>
539</ul>
540
541</div>
542
543<!-- ======================================================================= -->
544<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]545 <a name="sparc-be">Known problems with the SPARC back-end</a>
546</div>
547
548<div class="doc_text">
549
550<ul>
551<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
552 support the 64-bit SPARC ABI (-m64).</li>
553</ul>
554
555</div>
556
557<!-- ======================================================================= -->
558<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]559 <a name="alpha-be">Known problems with the Alpha back-end</a>
560</div>
561
562<div class="doc_text">
563
564<ul>
565
566<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
567appropriate nops inserted to ensure restartability.</li>
568
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]569</ul>
570</div>
571
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]572<!-- ======================================================================= -->
573<div class="doc_subsection">
574 <a name="ia64-be">Known problems with the IA64 back-end</a>
575</div>
576
577<div class="doc_text">
578
579<ul>
580
581<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
582made where the argument is not 16-byte aligned, as required on IA64. (Strictly
583speaking this is not a bug in the IA64 back-end; it will also be encountered
584when building C++ programs using the C back-end.)</li>
585
586<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
587ABI compliant layout of v-tables</a>. In particular, it just stores function
588pointers instead of function descriptors in the vtable. This bug prevents
589mixing C++ code compiled with LLVM with C++ objects compiled by other C++
590compilers.</li>
591
592<li>There are a few ABI violations which will lead to problems when mixing LLVM
593output with code built with other compilers, particularly for floating-point
594programs.</li>
595
596<li>Defining vararg functions is not supported (but calling them is ok).</li>
597
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]598<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]599</ul>
600
601</div>
602
603<!-- ======================================================================= -->
604<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]605 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]606</div>
607
608<div class="doc_text">
609
610<ul>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]611<li><a href="http://llvm.org/PR802">The C backend does not support inline
612 assembly code</a>.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]613</ul>
614
615</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]616
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]617
618<!-- ======================================================================= -->
619<div class="doc_subsection">
620 <a name="c-fe">Known problems with the C front-end</a>
621</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]622
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]623<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]624<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]625
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]626<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]627
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]628<p>llvm-gcc4 does not currently support <a href="http://llvm.org/PR869">Link-Time
629Optimization</a> on most platforms "out-of-the-box". Please inquire on the
630llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]631
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]632<p>FIXME: the list of supported stuff below needs to be updated. We do support
633tls now, what else??</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]634</div>
635
636<!-- _______________________________________________________________________ -->
637<div class="doc_subsubsection">
638 Notes
639</div>
640
641<div class="doc_text">
642
643<ul>
644
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]645<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]646support for floating point data types of any size other than 32 and 64
647bits.</li>
648
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]649<li>Although many GCC extensions are supported, some are not. In particular,
650 the following extensions are known to <b>not be</b> supported:
651 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]652 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]653 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>: As in Algol and Pascal, lexical scoping of functions.</li>
654 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
Tanya Lattner014e5f52004-12-08 18:25:34 +0000[diff] [blame]655 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]656 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]657 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]658
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]659 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]660 attribute means that the LLVM compiler ignores the presence of the attribute,
661 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]662 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]663 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]664
665 <ol>
666 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
667 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]668 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]669
670 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]671
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]672 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]673 return.<br>
674
Anton Korobeynikov9ec81372007-05-10 08:26:24 +0000[diff] [blame]675 <b>Supported:</b> <tt>alias</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Anton Korobeynikov9413de32006-11-18 08:04:48 +0000[diff] [blame]676 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
Anton Korobeynikov9ec81372007-05-10 08:26:24 +0000[diff] [blame]677 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noreturn</tt>, <tt>regparm</tt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]678 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
679 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]680
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]681 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]682 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
683 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
684
Anton Korobeynikov9ec81372007-05-10 08:26:24 +0000[diff] [blame]685 <b>Unsupported:</b> All other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]686
687 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
688 Specifying attributes of variables.<br>
Anton Korobeynikov9ec81372007-05-10 08:26:24 +0000[diff] [blame]689 <b>Supported:</b> <tt>alias</tt>, <tt>cleanup</tt>, <tt>common</tt>,
690 <tt>nocommon</tt>, <tt>deprecated</tt>, <tt>dllimport</tt>,
691 <tt>dllexport</tt>, <tt>section</tt>, <tt>transparent_union</tt>,
692 <tt>unused</tt>, <tt>used</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]693
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]694 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]695 <tt>shared</tt>, <tt>tls_model</tt>,
696 <tt>vector_size</tt>, all target specific attributes.
Anton Korobeynikov9413de32006-11-18 08:04:48 +0000[diff] [blame]697 </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]698
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]699 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]700 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]701 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]702
703 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
704 all target specific attributes.</li>
705
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]706 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
707 Other built-in functions.<br>
708 We support all builtins which have a C language equivalent (e.g.,
709 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
710 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerceebeb62004-06-18 06:26:29 +0000[diff] [blame]711 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
712 (currently ignored). We also support builtins for ISO C99 floating
Chris Lattner7939b782005-05-07 02:21:21 +0000[diff] [blame]713 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
714 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
715 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]716 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]717
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]718 <p>The following extensions <b>are</b> known to be supported:</p>
719
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]720 <ol>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000[diff] [blame]721 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html#Labels%20as%20Values">Labels as Values</a>: Getting pointers to labels and computed gotos.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]722 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
723 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
Tanya Lattnerca26c3e2004-06-22 03:48:17 +0000[diff] [blame]724 <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]725 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
726 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
727 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
728 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
729 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
730 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
731 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.</li>
732 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]733 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.</li>
734 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
735 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Asm-Labels.html#Asm%20Labels">Asm Labels</a>: Specifying the assembler name to use for a C symbol.</li>
736 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>: Defining variables residing in specified registers.</li>
737 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.</li>
738 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]739 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.</li>
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]740 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html#Pointer%20Arith">Pointer Arith</a>: Arithmetic on <code>void</code>-pointers and function pointers.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]741 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]742 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
743or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]744 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]745 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html#Cast%20to%20Union">Cast to Union</a>: Casting to union type from any member of the union.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]746 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
747 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
748 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
Tanya Lattner78537e42004-12-08 18:29:38 +0000[diff] [blame]749 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]750 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
751 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Character-Escapes.html#Character%20Escapes">Character Escapes</a>: <code>\e</code> stands for the character &lt;ESC&gt;.</li>
752 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
753 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
754 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alternate-Keywords.html#Alternate%20Keywords">Alternate Keywords</a>:<code>__const__</code>, <code>__asm__</code>, etc., for header files.</li>
755 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Incomplete-Enums.html#Incomplete%20Enums">Incomplete Enums</a>: <code>enum foo;</code>, with details to follow.</li>
756 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html#Function%20Names">Function Names</a>: Printable strings which are the name of the current function.</li>
Chris Lattner25795bc2004-02-14 04:08:29 +0000[diff] [blame]757 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Return-Address.html#Return%20Address">Return Address</a>: Getting the return or frame address of a function.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]758 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.</li>
759 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]760 </ol></li>
761
762</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]763
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]764<p>If you run into GCC extensions which have not been included in any of these
765lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]766
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]767</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]768
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]769<!-- ======================================================================= -->
770<div class="doc_subsection">
771 <a name="c++-fe">Known problems with the C++ front-end</a>
772</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]773
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]774<div class="doc_text">
775
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]776<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]777tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]778itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]779
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]780<ul>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]781<li>llvm-gcc4 only has partial support for <a href="http://llvm.org/PR870">C++
782Exception Handling</a>, and it is not enabled by default.</li>
783
784<!-- NO EH Support!
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]785
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]786<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]787 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]788 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]789 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]790 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]791
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]792<li>The LLVM C++ front-end follows the <a
793 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
794 This document, which is not Itanium specific, specifies a standard for name
795 mangling, class layout, v-table layout, RTTI formats, and other C++
796 representation issues. Because we use this API, code generated by the LLVM
797 compilers should be binary compatible with machine code generated by other
798 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]799 <i>However</i>, the exception handling mechanism used by llvm-gcc3 is very
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]800 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]801 interact correctly</b>. </li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]802-->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]803</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]804
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]805</div>
806
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]807
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]808
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]809<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]810<div class="doc_section">
811 <a name="additionalinfo">Additional Information</a>
812</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]813<!-- *********************************************************************** -->
814
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]815<div class="doc_text">
816
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]817<p>A wide variety of additional information is available on the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]818href="http://llvm.org">LLVM web page</a>, including <a
819href="http://llvm.org/docs/">documentation</a> and <a
820href="http://llvm.org/pubs/">publications describing algorithms and
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]821components implemented in LLVM</a>. The web page also contains versions of the
822API documentation which is up-to-date with the CVS version of the source code.
823You can access versions of these documents specific to this release by going
824into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]825
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]826<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]827us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]828lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]829
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]830</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]831
832<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]833
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]834<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]835<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]836 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]837 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
838 <a href="http://validator.w3.org/check/referer"><img
839 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
840
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]841 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]842 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]843</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]844
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]845</body>
846</html>