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7 <title>LLVM 2.6 Release Notes</title>
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9<body>
10
11<div class="doc_title">LLVM 2.6 Release Notes</div>
12
13<ol>
14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#subproj">Sub-project Status Update</a></li>
16 <li><a href="#externalproj">External Projects Using LLVM 2.6</a></li>
17 <li><a href="#whatsnew">What's New in LLVM 2.6?</a></li>
18 <li><a href="GettingStarted.html">Installation Instructions</a></li>
19 <li><a href="#portability">Portability and Supported Platforms</a></li>
20 <li><a href="#knownproblems">Known Problems</a></li>
21 <li><a href="#additionalinfo">Additional Information</a></li>
22</ol>
23
24<div class="doc_author">
25 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
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
36<p>This document contains the release notes for the LLVM Compiler
37Infrastructure, release 2.6. Here we describe the status of LLVM, including
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>
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
45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
46List</a> is a good place to send them.</p>
47
48<p>Note that if you are reading this file from a Subversion checkout or the
49main LLVM web page, this document applies to the <i>next</i> release, not the
50current one. To see the release notes for a specific release, please see the
51<a href="http://llvm.org/releases/">releases page</a>.</p>
52
53</div>
54
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame^]55 Many new papers added to /pubs/
56 Machine LICM, hoists things like constant pool loads, loads from readonly stubs, vector constant synthesization code, etc.
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]57 Machine Sinking
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame^]58 Regalloc improvements for commuting, various spiller peephole optimizations, cross-class coalescing.
59 Support for debug line numbers when optimization enabled
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]60 gold lto plugin
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame^]61
62 target-specific intrinsics (r63765)
63 <tt>llc -enable-value-prop</tt>, propagation of value info (sign/zero ext info) from one MBB to another
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]64 interpreter + libffi
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame^]65 LLVMContext
66 Preliminary support for addrspace 256 -> GS, 257 -> FS, known problems: CodeGenerator.html#x86_memory
67
68Add support for the PowerPC 64-bit SVR4 ABI.
69
70 NSW/NUW/exact div
71 Inbounds for GEP
72 SRoA improvements for vector unions, memset, arbitrary weird bitfield accesses etc. It now produces "strange" sized integers.
73 pre-alloc splitter??
74 Callgraph + SCCPassMgr??
75 X86: Support for softfloat modes, typically used by OS kernels.
76 MC:
77 MCSection, MCAsmInfo
78 MCInstPrinter did it make it in?
79 MCInst (X86 using it so far)
80 Rewrite of X86 GV selection logic: TargetOperand flags on ExternalSymbol, GV, etc operands.
81 Can parse and re-print out an darwin-x86 .s file.
82 TargetLoweringObjectFile, MCSectionKind
83 Verrrry early start of a macho writer.
84
85 ELF Writer? How stable?
86
87 LSR promotes int induction variables to 64-bit on 64-bit targets, major perf boost for numerical code.
88 LSR now analyzes pointer expressions (e.g. getelementptrs), not just integers.
89 Stack slot coloring for register spills (denser stack frames)
90 SelectionDAGS: New BuildVectorSDNode (r65296), and ISD::VECTOR_SHUFFLE (r69952 / PR2957)
91 New PrettyStackTrace, crashes of llvm tools should give some indication of what the compiler was doing at the time of the crash (e.g. running a pass), and print out command line arguments.
92 new linkage types linkonce_odr, weak_odr, linker_private, and available_externally.
93 Inliner reuse stack space when inlining arrays?
94
95 Regalloc hints for allocation stuff: Evan r73381/r73671. Finished/enabled?
96 API Cleanup:
97 no use of hash_set/hash_map, no more llvm::OStream
98 Use raw_ostream for everything, killed off llvm/Streams.h and DOUT
99
100 Mips now supports O32 Calling Convention
101
102 StringRef class, Twine class.
103 New BlackFin backend.
104
105 Shrink wrapping support in PEI, what is the state of it?
106
107 X86-64: better modeling of implicit zero extensions, eliminates a lot of redundant zexts
108 X86-64 TLS support for local exec and initial exec.
109 X86 - Better modeling of H registerts as subregs.
110 Getelementpr instruction now allows any integer type for array/pointer indexes.
111
112 include/llvm/Analysis/LiveValues.h => dead??
113 lib/Analysis/LoopVR.cpp ==> dead??
114 include/llvm/CodeGen/LazyLiveness.h ==> dead?
115 lib/Transforms/IPO/MergeFunctions.cpp ==> dead?
116 llvm/Analysis/PointerTracking.h ==> dead??
117 PRedSimplify -> Ask vmkit if it is still useful and for testcases.
118
119 ARM calling convention code is now tblgen generated instead of manual.
120 ARM: NEON support. neonfp for doing single precision fp with neon instead of VFP.
121 Tblgen now supports multiclass inheritance.
122 Unladen swallow as user?
123 Loop index split disabled by default?
124
125 New WeakVH and AssertingVH and CallbackVH classes.
126 New llvm/ADT/Triple class.
127 Removed the IA64 backend.
128 Profile info improvements by Andreas Neustifter.
129 PostRA scheduler improvements David Goodwin.
130
131 New MSP430 and SystemZ backends.
132 llvm-gcc now supports a new TCE target.
133 klee web page at klee.llvm.org
134 New llvm/System/Atomic.h, llvm/System/RWMutex.h for portable atomic ops, rw locks.
135 llvm_start_multithreaded: ProgrammersMAnual.html#threading
136
137 Tablegen now supports a number of new string and list operations like
138 !(subst), !(foreach), !car, !cdr, !null, !if, !cast.
139 New fadd, fsub, fmul instructions and classes.
140 New MachineVerifier pass.
141 Enabled GVN Load PRE.
142 ARM AAPCS-VFP hard float ABI is supported.
143
144 LLVM build now builds all libraries as .a files instead of some
145 libraries as relinked .o files. This requires some APIs like
146 InitializeAllTargets.h. TargetRegistry!
147
148 ARM Thumb2 support: status?
149 CBE status: not part of the release criteria.
150
151 New SourceMgr, SMLoc classes for simple parsers with caret diagnostics and #include support, (used by
152 tablegen, llvm-mc, the .ll parser, FileCheck, etc)
153 FileCheck! + CHECK-NEXT
154 New compiler-rt project.
155 New Static Single Information (SSI) construction pass (not used by anything yet, experimental).
156
157 llvm_report_error() error handling API (llvm/Support/ErrorHandling.h)
158
159 x86: Vector icmp/fcmp now work with SSE codegen.
160 X86: all global variable reference logic is now in ClassifyGlobalReference.
161 JIT support for oprofile (r75279), configure with --with-oprofile. Now we get line # and function info for JIT'd functions.
162 Mention gcc plugin.
163
164 New EngineBuilder class for creating JITs: r76276 Reid Kleckner <reid at kleckner.net>
165
166 -asm-verbose now prints location info (with -g) and loop nest info.
167 JIT now supports generating more than 16M of code.
168
169removed the BigBlock register allocator, it had bitrotted.
170Target intrinsics can now return multiple results.
171
172 SSE 4.2 support.
173 Ada bindings for LLVM IR.
174 Many extensions to the C APIs.
175
176<!-- Unfinished features in 2.6:
177 Mention gcc plugin.
178 strong phi elim
179 variable debug info for optimized code
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]180 postalloc scheduler: anti dependence breaking, hazard recognizer?
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame^]181 metadata
182 loop dependence analysis
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]183 -->
184
185 <!-- for announcement email:
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame^]186 Logo web page.
187 llvm devmtg
188 compiler_rt
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]189 -->
190
191<!-- *********************************************************************** -->
192<div class="doc_section">
193 <a name="subproj">Sub-project Status Update</a>
194</div>
195<!-- *********************************************************************** -->
196
197<div class="doc_text">
198<p>
199The LLVM 2.6 distribution currently consists of code from the core LLVM
200repository &mdash;which roughly includes the LLVM optimizers, code generators
201and supporting tools &mdash; and the llvm-gcc repository. In addition to this
202code, the LLVM Project includes other sub-projects that are in development. The
203two which are the most actively developed are the <a href="#clang">Clang
204Project</a> and the <a href="#vmkit">VMKit Project</a>.
205</p>
206
207</div>
208
209
210<!--=========================================================================-->
211<div class="doc_subsection">
212<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
213</div>
214
215<div class="doc_text">
216
217<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
218a set of new 'LLVM native' front-end technologies for the LLVM optimizer and
219code generator. While Clang is not included in the LLVM 2.6 release, it is
220continuing to make major strides forward in all areas. Its C and Objective-C
221parsing and code generation support is now very solid. For example, it is
222capable of successfully building many real-world applications for X86-32
223and X86-64,
224including the <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">FreeBSD
225kernel</a> and <a href="http://gcc.gnu.org/gcc-4.2/">gcc 4.2</a>. C++ is also
226making <a href="http://clang.llvm.org/cxx_status.html">incredible progress</a>,
227and work on templates has recently started. If you are
228interested in fast compiles and good diagnostics, we encourage you to try it out
229by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
230and reporting any issues you hit to the <a
231href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
232list</a>.</p>
233
234<p>In the LLVM 2.6 time-frame, the Clang team has made many improvements:</p>
235
236<ul>
237<li>Something wonderful!</li>
Chris Lattnerc32a5322009-09-30 06:27:22 +0000[diff] [blame]238<li>AuroraUX / FreeBSD &amp; OpenBSD Toolchain support.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]239<li>Many many bugs are fixed and many features have been added.</li>
240</ul>
241</div>
242
243<!--=========================================================================-->
244<div class="doc_subsection">
245<a name="clangsa">Clang Static Analyzer</a>
246</div>
247
248<div class="doc_text">
249
250<p>Previously announced in the 2.4 LLVM release, the Clang project also
251includes an early stage static source code analysis tool for <a
252href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
253in C and Objective-C programs. The tool performs a growing set of checks to find
254bugs that occur on a specific path within a program.</p>
255
256<p>In the LLVM 2.6 time-frame there have been many significant improvements to
257XYZ.</p>
258
259<p>The set of checks performed by the static analyzer continues to expand, and
260future plans for the tool include full source-level inter-procedural analysis
261and deeper checks such as buffer overrun detection. There are many opportunities
262to extend and enhance the static analyzer, and anyone interested in working on
263this project is encouraged to get involved!</p>
264
265</div>
266
267<!--=========================================================================-->
268<div class="doc_subsection">
269<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
270</div>
271
272<div class="doc_text">
273<p>
274The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
275a JVM and a CLI Virtual Machines (Microsoft .NET is an
276implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
277
278<p>Following LLVM 2.6, VMKit has its XYZ release that you can find on its
279<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes
280bug fixes, cleanup and new features. The major changes are:</p>
281
282<ul>
283
284<li>Something wonderful!</li>
285
286</ul>
287</div>
288
289<!-- *********************************************************************** -->
290<div class="doc_section">
291 <a name="externalproj">External Projects Using LLVM 2.6</a>
292</div>
293<!-- *********************************************************************** -->
294
Chris Lattnerc32a5322009-09-30 06:27:22 +0000[diff] [blame]295
296<!--=========================================================================-->
297<div class="doc_subsection">
298<a name="macruby">MacRuby</a>
299</div>
300
301<div class="doc_text">
302
303<p>
304<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of
305core Mac OS X technologies, such as the Objective-C common runtime and garbage
306collector, and the CoreFoundation framework. It is principally developed by
307Apple and aims at enabling the creation of full-fledged Mac OS X applications.
308</p>
309
310<p>
311MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby
312expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception
313handling.</p>
314
315</div>
316
317
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]318<!--=========================================================================-->
319<div class="doc_subsection">
320<a name="pure">Pure</a>
321</div>
322
323<div class="doc_text">
324<p>
325<a href="http://pure-lang.googlecode.com/">Pure</a>
326is an algebraic/functional programming language based on term rewriting.
327Programs are collections of equations which are used to evaluate expressions in
328a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
329lexical closures, a hygienic macro system (also based on term rewriting),
330built-in list and matrix support (including list and matrix comprehensions) and
331an easy-to-use C interface. The interpreter uses LLVM as a backend to
332 JIT-compile Pure programs to fast native code.</p>
333
334<p>In addition to the usual algebraic data structures, Pure also has
335MATLAB-style matrices in order to support numeric computations and signal
336processing in an efficient way. Pure is mainly aimed at mathematical
337applications right now, but it has been designed as a general purpose language.
338The dynamic interpreter environment and the C interface make it possible to use
339it as a kind of functional scripting language for many application areas.
340</p>
341</div>
342
343
344<!--=========================================================================-->
345<div class="doc_subsection">
346<a name="ldc">LLVM D Compiler</a>
347</div>
348
349<div class="doc_text">
350<p>
351<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
352the D Programming Language using the LLVM optimizer and code generator.
353The LDC project works great with the LLVM 2.6 release. General improvements in
354this
355cycle have included new inline asm constraint handling, better debug info
356support, general bugfixes, and better x86-64 support. This has allowed
357some major improvements in LDC, getting us much closer to being as
358fully featured as the original DMD compiler from DigitalMars.
359</p>
360</div>
361
362<!--=========================================================================-->
363<div class="doc_subsection">
364<a name="RoadsendPHP">Roadsend PHP</a>
365</div>
366
367<div class="doc_text">
368<p><a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
369source implementation of the PHP programming
370language that uses LLVM for its optimizer, JIT, and static compiler. This is a
371reimplementation of an earlier project that is now based on LLVM.</p>
372</div>
373
Jeffrey Yasskinba2aa782009-06-24 21:09:13 +0000[diff] [blame]374<!--=========================================================================-->
375<div class="doc_subsection">
376<a name="Unladen Swallow">Unladen Swallow</a>
377</div>
378
379<div class="doc_text">
380<p><a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
381branch of <a href="http://python.org/">Python</a> intended to be fully
382compatible and significantly faster. It uses LLVM's optimization passes and JIT
383compiler.</p>
384</div>
385
Jeffrey Yasskin5e98cb72009-06-24 21:26:42 +0000[diff] [blame]386<!--=========================================================================-->
387<div class="doc_subsection">
388<a name="Rubinius">Rubinius</a>
389</div>
390
391<div class="doc_text">
392<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is a new virtual
393machine for Ruby. It leverages LLVM to dynamically compile Ruby code down to
394machine code using LLVM's JIT.</p>
395</div>
396
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]397
398<!-- *********************************************************************** -->
399<div class="doc_section">
400 <a name="whatsnew">What's New in LLVM 2.6?</a>
401</div>
402<!-- *********************************************************************** -->
403
404<div class="doc_text">
405
406<p>This release includes a huge number of bug fixes, performance tweaks, and
407minor improvements. Some of the major improvements and new features are listed
408in this section.
409</p>
410</div>
411
412<!--=========================================================================-->
413<div class="doc_subsection">
414<a name="majorfeatures">Major New Features</a>
415</div>
416
417<div class="doc_text">
418
419<p>LLVM 2.6 includes several major new capabilities:</p>
420
421<ul>
422<li>Something wonderful!</li>
Edward O'Callaghan50310f92009-08-22 02:17:22 +0000[diff] [blame]423<li>LLVM 2.6 includes a brand new experimental LLVM bindings to the Ada2005 programming language.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]424</ul>
425
426</div>
427
428
429<!--=========================================================================-->
430<div class="doc_subsection">
431<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
432</div>
433
434<div class="doc_text">
435
436<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC
437front-ends and driver with the LLVM optimizer and code generator. It currently
438includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
439
440<ul>
441<li>Something wonderful!</li>
442</ul>
443
444</div>
445
446
447<!--=========================================================================-->
448<div class="doc_subsection">
449<a name="coreimprovements">LLVM IR and Core Improvements</a>
450</div>
451
452<div class="doc_text">
453<p>LLVM IR has several new features that are used by our existing front-ends and
454can be useful if you are writing a front-end for LLVM:</p>
455
456<ul>
457<li>Something wonderful!</li>
458</ul>
459
460</div>
461
462<!--=========================================================================-->
463<div class="doc_subsection">
464<a name="optimizer">Optimizer Improvements</a>
465</div>
466
467<div class="doc_text">
468
469<p>In addition to a large array of bug fixes and minor performance tweaks, this
470release includes a few major enhancements and additions to the optimizers:</p>
471
472<ul>
473
474<li>Something wonderful!</li>
475
476</ul>
477
478</div>
479
480<!--=========================================================================-->
481<div class="doc_subsection">
482<a name="codegen">Target Independent Code Generator Improvements</a>
483</div>
484
485<div class="doc_text">
486
487<p>We have put a significant amount of work into the code generator
488infrastructure, which allows us to implement more aggressive algorithms and make
489it run faster:</p>
490
491<ul>
492
493<li>Something wonderful!</li>
494</ul>
495</div>
496
497<!--=========================================================================-->
498<div class="doc_subsection">
499<a name="x86">X86-32 and X86-64 Target Improvements</a>
500</div>
501
502<div class="doc_text">
503<p>New features of the X86 target include:
504</p>
505
506<ul>
507
508<li>Something wonderful!</li>
509</ul>
510
511</div>
512
513<!--=========================================================================-->
514<div class="doc_subsection">
515<a name="pic16">PIC16 Target Improvements</a>
516</div>
517
518<div class="doc_text">
519<p>New features of the PIC16 target include:
520</p>
521
522<ul>
523<li>Something wonderful!</li>
524</ul>
525
526<p>Things not yet supported:</p>
527
528<ul>
529<li>Floating point.</li>
530<li>Passing/returning aggregate types to and from functions.</li>
531<li>Variable arguments.</li>
532<li>Indirect function calls.</li>
533<li>Interrupts/programs.</li>
534<li>Debug info.</li>
535</ul>
536
537</div>
538
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]539<!--=========================================================================-->
540<div class="doc_subsection">
541<a name="ARM">ARM Target Improvements</a>
542</div>
543
544<div class="doc_text">
545<p>New features of the ARM target include:
546</p>
547
548<ul>
549
550<li>Preliminary support for processors, such as the Cortex-A8 and Cortex-A9,
Sandeep Patel64e39612009-08-20 15:01:16 +0000[diff] [blame]551that implement version v7-A of the ARM architecture. The ARM backend now
552supports both the Thumb2 and Advanced SIMD (Neon) instruction sets. The
553AAPCS-VFP "hard float" calling conventions are also supported with the
554<tt>-float-abi=hard</tt> flag. These features are still somewhat experimental
555and subject to change. The Neon intrinsics, in particular, may change in future
556releases of LLVM.
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]557</li>
558</ul>
559
560</div>
561
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]562
563<!--=========================================================================-->
564<div class="doc_subsection">
565<a name="llvmc">Improvements in LLVMC</a>
566</div>
567
568<div class="doc_text">
569<p>New features include:</p>
570
571<ul>
572<li>Something wonderful!</li>
573</ul>
574
575</div>
576
577
578<!--=========================================================================-->
579<div class="doc_subsection">
580<a name="changes">Major Changes and Removed Features</a>
581</div>
582
583<div class="doc_text">
584
585<p>If you're already an LLVM user or developer with out-of-tree changes based
Owen Andersone27be3a2009-07-02 16:48:38 +0000[diff] [blame]586on LLVM 2.5, this section lists some "gotchas" that you may run into upgrading
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]587from the previous release.</p>
588
589<ul>
590
591<li>Something horrible!</li>
592
593</ul>
594
595
596<p>In addition, many APIs have changed in this release. Some of the major LLVM
597API changes are:</p>
598
599<ul>
Owen Andersone27be3a2009-07-02 16:48:38 +0000[diff] [blame]600<li>LLVM's global uniquing tables for <tt>Type</tt>s and <tt>Constant</tt>s have
601 been privatized into members of an <tt>LLVMContext</tt>. A number of APIs
602 now take an <tt>LLVMContext</tt> as a parameter. To smooth the transition
603 for clients that will only ever use a single context, the new
604 <tt>getGlobalContext()</tt> API can be used to access a default global
605 context which can be passed in any and all cases where a context is
606 required.
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]607<li>The <tt>getABITypeSize</tt> methods are now called <tt>getAllocSize</tt>.</li>
Dan Gohmanf667e7e2009-07-07 20:05:15 +0000[diff] [blame]608<li>The <tt>Add</tt>, <tt>Sub</tt>, and <tt>Mul</tt> operators are no longer
609 overloaded for floating-point types. Floating-point addition, subtraction,
610 and multiplication are now represented with new operators <tt>FAdd</tt>,
611 <tt>FSub</tt>, and <tt>FMul</tt>. In the <tt>IRBuilder</tt> API,
612 <tt>CreateAdd</tt>, <tt>CreateSub</tt>, <tt>CreateMul</tt>, and
613 <tt>CreateNeg</tt> should only be used for integer arithmetic now;
614 <tt>CreateFAdd</tt>, <tt>CreateFSub</tt>, <tt>CreateFMul</tt>, and
615 <tt>CreateFNeg</tt> should now be used for floating-point arithmetic.</li>
Daniel Dunbar02e73132009-07-12 20:41:27 +0000[diff] [blame]616<li>The DynamicLibrary class can no longer be constructed, its functionality has
617 moved to static member functions.</li>
Dan Gohmane4d54d72009-07-15 19:59:19 +0000[diff] [blame]618<li><tt>raw_fd_ostream</tt>'s constructor for opening a given filename now
619 takes an extra <tt>Force</tt> argument. If <tt>Force</tt> is set to
620 <tt>false</tt>, an error will be reported if a file with the given name
621 already exists. If <tt>Force</tt> is set to <tt>true</tt>, the file will
622 be silently truncated (which is the behavior before this flag was
623 added).</li>
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]624<li><tt>SCEVHandle</tt> no longer exists, because reference counting is no
625longer done for <tt>SCEV*</tt> objects, instead <tt>const SCEV*</tt> should be
626used.</li>
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]627
Daniel Dunbar6e0d1cb2009-07-25 04:41:11 +0000[diff] [blame]628<li>Many APIs, notably <tt>llvm::Value</tt>, now use the <tt>StringRef</tt>
629and <tt>Twine</tt> classes instead of passing <tt>const char*</tt>
630or <tt>std::string</tt>, as described in
631the <a href="ProgrammersManual.html#string_apis">Programmer's Manual</a>. Most
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]632clients should be unaffected by this transition, unless they are used to <tt>Value::getName()</tt> returning a string. Here are some tips on updating to 2.6:
633 <ul>
634 <li><tt>getNameStr()</tt> is still available, and matches the old
635 behavior. Replacing <tt>getName()</tt> calls with this is an safe option,
636 although more efficient alternatives are now possible.</li>
637
638 <li>If you were just relying on <tt>getName()</tt> being able to be sent to
639 a <tt>std::ostream</tt>, consider migrating
640 to <tt>llvm::raw_ostream</tt>.</li>
641
642 <li>If you were using <tt>getName().c_str()</tt> to get a <tt>const
643 char*</tt> pointer to the name, you can use <tt>getName().data()</tt>.
644 Note that this string (as before), may not be the entire name if the
645 name containts embedded null characters.</li>
646
647 <li>If you were using operator plus on the result of <tt>getName()</tt> and
648 treating the result as an <tt>std::string</tt>, you can either
649 uses <tt>Twine::str</tt> to get the result as an <tt>std::string</tt>, or
650 could move to a <tt>Twine</tt> based design.</li>
Daniel Dunbar03d76512009-07-25 23:55:21 +0000[diff] [blame]651
652 <li><tt>isName()</tt> should be replaced with comparison
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]653 against <tt>getName()</tt> (this is now efficient).
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]654 </ul>
655</li>
656
Daniel Dunbara5881e32009-07-26 02:12:58 +0000[diff] [blame]657<li>The registration interfaces for backend Targets has changed (what was
Daniel Dunbard6b06b12009-07-26 05:41:39 +0000[diff] [blame]658previously TargetMachineRegistry). For backend authors, see the <a href="WritingAnLLVMBackend.html#TargetRegistration">Writing An LLVM Backend</a> guide. For clients, the notable API changes are:
659 <ul>
660 <li><tt>TargetMachineRegistry</tt> has been renamed
661 to <tt>TargetRegistry</tt>.</li>
662
663 <li>Clients should move to using the <tt>TargetRegistry::lookupTarget()</tt>
664 function to find targets.</li>
665 </ul>
666</li>
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]667
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]668<li>llvm-dis now fails if output file exists, instead of dumping to stdout.
Daniel Dunbar6e0d1cb2009-07-25 04:41:11 +0000[diff] [blame]669FIXME: describe any other tool changes due to the raw_fd_ostream change. FIXME:
670This is not an API change, maybe there should be a tool changes section?</li>
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]671<li>temporarely due to Context API change passes should call doInitialization()
672method of the pass they inherit from, otherwise Context is NULL.
673FIXME: remove this entry when this is no longer needed.<li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]674</ul>
675
676</div>
677
678
679
680<!-- *********************************************************************** -->
681<div class="doc_section">
682 <a name="portability">Portability and Supported Platforms</a>
683</div>
684<!-- *********************************************************************** -->
685
686<div class="doc_text">
687
688<p>LLVM is known to work on the following platforms:</p>
689
690<ul>
691<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]692Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like systems).</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]693<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
694and 64-bit modes.</li>
695<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
696<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
697 support is available for native builds with Visual C++).</li>
698<li>Sun UltraSPARC workstations running Solaris 10.</li>
699<li>Alpha-based machines running Debian GNU/Linux.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]700</ul>
701
702<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
703to the machine and operating system on which it is built. However, minor
704porting may be required to get LLVM to work on new platforms. We welcome your
705portability patches and reports of successful builds or error messages.</p>
706
707</div>
708
709<!-- *********************************************************************** -->
710<div class="doc_section">
711 <a name="knownproblems">Known Problems</a>
712</div>
713<!-- *********************************************************************** -->
714
715<div class="doc_text">
716
717<p>This section contains significant known problems with the LLVM system,
718listed by component. If you run into a problem, please check the <a
719href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
720there isn't already one.</p>
721
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]722<ul>
Chris Lattneraedb59a2009-07-21 23:17:26 +0000[diff] [blame]723<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]724using the stock GCC 3.x.x series 'out the box',
725See: <a href="#brokengcc">Broken versions of GCC and other tools</a>.
726However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
727for x86/x64 has been made available from the third party AuroraUX Project
728that has been meticulously tested for bootstrapping LLVM & Clang.</li>
729</ul>
730
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]731</div>
732
733<!-- ======================================================================= -->
734<div class="doc_subsection">
735 <a name="experimental">Experimental features included with this release</a>
736</div>
737
738<div class="doc_text">
739
740<p>The following components of this LLVM release are either untested, known to
741be broken or unreliable, or are in early development. These components should
742not be relied on, and bugs should not be filed against them, but they may be
743useful to some people. In particular, if you would like to work on one of these
744components, please contact us on the <a
745href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
746
747<ul>
Dan Gohmand2cb3d22009-07-24 00:30:09 +0000[diff] [blame]748<li>The MSIL, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]749<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
750 supported value for this option.</li>
751</ul>
752
753</div>
754
755<!-- ======================================================================= -->
756<div class="doc_subsection">
757 <a name="x86-be">Known problems with the X86 back-end</a>
758</div>
759
760<div class="doc_text">
761
762<ul>
763 <li>The X86 backend does not yet support
764 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
765 floating point stack</a>. It supports the 'f' and 't' constraints, but not
766 'u'.</li>
767 <li>The X86 backend generates inefficient floating point code when configured
768 to generate code for systems that don't have SSE2.</li>
769 <li>Win64 code generation wasn't widely tested. Everything should work, but we
770 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
771 runtime currently due
772 to <a href="http://llvm.org/PR2255">several</a>
773 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
774 the
775 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
776 <li>The X86-64 backend does not yet support the LLVM IR instruction
777 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
778 argument constructs on X86-64 by lowering them manually.</li>
779</ul>
780
781</div>
782
783<!-- ======================================================================= -->
784<div class="doc_subsection">
785 <a name="ppc-be">Known problems with the PowerPC back-end</a>
786</div>
787
788<div class="doc_text">
789
790<ul>
791<li>The Linux PPC32/ABI support needs testing for the interpreter and static
792compilation, and lacks support for debug information.</li>
793</ul>
794
795</div>
796
797<!-- ======================================================================= -->
798<div class="doc_subsection">
799 <a name="arm-be">Known problems with the ARM back-end</a>
800</div>
801
802<div class="doc_text">
803
804<ul>
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]805<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
806and not well tested. Some features may not work at all, and the code quality
807may be poor in some cases.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]808<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
809processors, thumb programs can crash or produce wrong
810results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
811<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
812</li>
813<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
814 execute
815programs compiled with LLVM. Please use more recent versions of QEMU.</li>
816</ul>
817
818</div>
819
820<!-- ======================================================================= -->
821<div class="doc_subsection">
822 <a name="sparc-be">Known problems with the SPARC back-end</a>
823</div>
824
825<div class="doc_text">
826
827<ul>
828<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
829 support the 64-bit SPARC ABI (-m64).</li>
830</ul>
831
832</div>
833
834<!-- ======================================================================= -->
835<div class="doc_subsection">
836 <a name="mips-be">Known problems with the MIPS back-end</a>
837</div>
838
839<div class="doc_text">
840
841<ul>
842<li>The O32 ABI is not fully supported.</li>
843<li>64-bit MIPS targets are not supported yet.</li>
844</ul>
845
846</div>
847
848<!-- ======================================================================= -->
849<div class="doc_subsection">
850 <a name="alpha-be">Known problems with the Alpha back-end</a>
851</div>
852
853<div class="doc_text">
854
855<ul>
856
857<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
858appropriate nops inserted to ensure restartability.</li>
859
860</ul>
861</div>
862
863<!-- ======================================================================= -->
864<div class="doc_subsection">
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]865 <a name="c-be">Known problems with the C back-end</a>
866</div>
867
868<div class="doc_text">
869
870<ul>
871<li><a href="http://llvm.org/PR802">The C backend has only basic support for
872 inline assembly code</a>.</li>
873<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
874 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
875 C++ code compiled with <tt>llc</tt> or native compilers.</li>
876<li>The C backend does not support all exception handling constructs.</li>
877<li>The C backend does not support arbitrary precision integers.</li>
878</ul>
879
880</div>
881
882
883<!-- ======================================================================= -->
884<div class="doc_subsection">
885 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
886</div>
887
888<div class="doc_text">
889
890<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
891Optimization</a> on most platforms "out-of-the-box". Please inquire on the
892LLVMdev mailing list if you are interested.</p>
893
894<p>The only major language feature of GCC not supported by llvm-gcc is
895 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
896 are only supported on some targets. For example, trampolines are only
897 supported on some targets (these are used when you take the address of a
898 nested function).</p>
899
900<p>If you run into GCC extensions which are not supported, please let us know.
901</p>
902
903</div>
904
905<!-- ======================================================================= -->
906<div class="doc_subsection">
907 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
908</div>
909
910<div class="doc_text">
911
912<p>The C++ front-end is considered to be fully
913tested and works for a number of non-trivial programs, including LLVM
914itself, Qt, Mozilla, etc.</p>
915
916<ul>
917<li>Exception handling works well on the X86 and PowerPC targets. Currently
918 only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
919</ul>
920
921</div>
922
923<!-- ======================================================================= -->
924<div class="doc_subsection">
925 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
926</div>
927
928<div class="doc_text">
929<ul>
930<li>Fortran support generally works, but there are still several unresolved bugs
931 in Bugzilla. Please see the tools/gfortran component for details.</li>
932</ul>
933</div>
934
935<!-- ======================================================================= -->
936<div class="doc_subsection">
937 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
938</div>
939
940<div class="doc_text">
941The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
942technology, and problems should be expected.
943<ul>
944<li>The Ada front-end currently only builds on X86-32. This is mainly due
945to lack of trampoline support (pointers to nested functions) on other platforms.
946However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
947which does support trampolines.</li>
948<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
949This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
950exception handling, which is used internally by the compiler.
951Workaround: configure with --disable-bootstrap.</li>
952<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
953and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
954(c380004 also fails with gcc-4.2 mainline).
955If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
956causes the compiler to go into an infinite loop, using up all system memory.</li>
957<li>Some GCC specific Ada tests continue to crash the compiler.</li>
958<li>The -E binder option (exception backtraces)
959<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
960crashing if an exception is raised. Workaround: do not use -E.</li>
961<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
962or finish at a non-byte offset</a> in a record. Workaround: do not pack records
963or use representation clauses that result in a field of a non-discrete type
964starting or finishing in the middle of a byte.</li>
965<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
966'main' as generated by the Ada binder to be invalid</a>.
967Workaround: hand edit the file to use pointers for <tt>argv</tt> and
968<tt>envp</tt> rather than integers.</li>
969<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
970ignored</a>.</li>
971</ul>
972</div>
973
Erick Tryzelaar17167be2009-09-28 04:42:55 +0000[diff] [blame]974<!-- ======================================================================= -->
975<div class="doc_subsection">
976 <a name="ocaml-bindingse">Known problems with the O'Caml bindings</a>
977</div>
978
979<div class="doc_text">
980
981<p>The Llvm.Linkage module is broken, and has incorrect values. Only
982Llvm.Linkage.External, Llvm.Linkage.Available_externally, and
983Llvm.Linkage.Link_once will be correct. If you need any of the other linkage
984modes, you'll have to write an external C library in order to expose the
985functionality. This has been fixed in the trunk.</p>
986</div>
987
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]988<!-- *********************************************************************** -->
989<div class="doc_section">
990 <a name="additionalinfo">Additional Information</a>
991</div>
992<!-- *********************************************************************** -->
993
994<div class="doc_text">
995
996<p>A wide variety of additional information is available on the <a
997href="http://llvm.org">LLVM web page</a>, in particular in the <a
998href="http://llvm.org/docs/">documentation</a> section. The web page also
999contains versions of the API documentation which is up-to-date with the
1000Subversion version of the source code.
1001You can access versions of these documents specific to this release by going
1002into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
1003
1004<p>If you have any questions or comments about LLVM, please feel free to contact
1005us via the <a href="http://llvm.org/docs/#maillist"> mailing
1006lists</a>.</p>
1007
1008</div>
1009
1010<!-- *********************************************************************** -->
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