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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 7b0a6816e7eeb9b2923706f65557e55d96f7246f / . / docs / ReleaseNotes-2.6.html
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7 <title>LLVM 2.6 Release Notes</title>
8</head>
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
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]56
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]57 MC:
58 MCSection, MCAsmInfo
59 MCInstPrinter did it make it in?
60 MCInst (X86 using it so far)
61 Rewrite of X86 GV selection logic: TargetOperand flags on ExternalSymbol, GV, etc operands.
62 Can parse and re-print out an darwin-x86 .s file.
63 TargetLoweringObjectFile, MCSectionKind
64 Verrrry early start of a macho writer.
65
66 ELF Writer? How stable?
67
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]68APIs:
69
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]70 Shrink wrapping support in PEI, what is the state of it?
71
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]72<!--
73Almost dead code.
74 include/llvm/Analysis/LiveValues.h => dan
75 lib/Analysis/LoopVR.cpp ==> dan/nick/owen
76 lib/Transforms/IPO/MergeFunctions.cpp
77 llvm/Analysis/PointerTracking.h
78-->
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]79
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]80 LLVM build now builds all libraries as .a files instead of some
81 libraries as relinked .o files. This requires some APIs like
82 InitializeAllTargets.h. TargetRegistry!
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]83
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]84
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]85
86<!-- Unfinished features in 2.6:
87 Mention gcc plugin.
88 strong phi elim
89 variable debug info for optimized code
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]90 postalloc scheduler: anti dependence breaking, hazard recognizer?
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]91 metadata
92 loop dependence analysis
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]93 -->
94
95 <!-- for announcement email:
Chris Lattnerc758fec2009-10-05 02:12:39 +0000[diff] [blame]96 Logo web page.
97 llvm devmtg
98 compiler_rt
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]99 klee web page at klee.llvm.org
100 Many new papers added to /pubs/
101 Mention gcc plugin.
102
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]103 -->
104
105<!-- *********************************************************************** -->
106<div class="doc_section">
107 <a name="subproj">Sub-project Status Update</a>
108</div>
109<!-- *********************************************************************** -->
110
111<div class="doc_text">
112<p>
113The LLVM 2.6 distribution currently consists of code from the core LLVM
114repository &mdash;which roughly includes the LLVM optimizers, code generators
115and supporting tools &mdash; and the llvm-gcc repository. In addition to this
116code, the LLVM Project includes other sub-projects that are in development. The
117two which are the most actively developed are the <a href="#clang">Clang
118Project</a> and the <a href="#vmkit">VMKit Project</a>.
119</p>
120
121</div>
122
123
124<!--=========================================================================-->
125<div class="doc_subsection">
126<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
127</div>
128
129<div class="doc_text">
130
131<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
132a set of new 'LLVM native' front-end technologies for the LLVM optimizer and
133code generator. While Clang is not included in the LLVM 2.6 release, it is
134continuing to make major strides forward in all areas. Its C and Objective-C
135parsing and code generation support is now very solid. For example, it is
136capable of successfully building many real-world applications for X86-32
137and X86-64,
138including the <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">FreeBSD
139kernel</a> and <a href="http://gcc.gnu.org/gcc-4.2/">gcc 4.2</a>. C++ is also
140making <a href="http://clang.llvm.org/cxx_status.html">incredible progress</a>,
141and work on templates has recently started. If you are
142interested in fast compiles and good diagnostics, we encourage you to try it out
143by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
144and reporting any issues you hit to the <a
145href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
146list</a>.</p>
147
148<p>In the LLVM 2.6 time-frame, the Clang team has made many improvements:</p>
149
150<ul>
151<li>Something wonderful!</li>
Chris Lattnerc32a5322009-09-30 06:27:22 +0000[diff] [blame]152<li>AuroraUX / FreeBSD &amp; OpenBSD Toolchain support.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]153<li>Many many bugs are fixed and many features have been added.</li>
154</ul>
155</div>
156
157<!--=========================================================================-->
158<div class="doc_subsection">
159<a name="clangsa">Clang Static Analyzer</a>
160</div>
161
162<div class="doc_text">
163
164<p>Previously announced in the 2.4 LLVM release, the Clang project also
165includes an early stage static source code analysis tool for <a
166href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
167in C and Objective-C programs. The tool performs a growing set of checks to find
168bugs that occur on a specific path within a program.</p>
169
170<p>In the LLVM 2.6 time-frame there have been many significant improvements to
171XYZ.</p>
172
173<p>The set of checks performed by the static analyzer continues to expand, and
174future plans for the tool include full source-level inter-procedural analysis
175and deeper checks such as buffer overrun detection. There are many opportunities
176to extend and enhance the static analyzer, and anyone interested in working on
177this project is encouraged to get involved!</p>
178
179</div>
180
181<!--=========================================================================-->
182<div class="doc_subsection">
183<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
184</div>
185
186<div class="doc_text">
187<p>
188The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
189a JVM and a CLI Virtual Machines (Microsoft .NET is an
190implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
191
192<p>Following LLVM 2.6, VMKit has its XYZ release that you can find on its
193<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes
194bug fixes, cleanup and new features. The major changes are:</p>
195
196<ul>
197
198<li>Something wonderful!</li>
199
200</ul>
201</div>
202
203<!-- *********************************************************************** -->
204<div class="doc_section">
205 <a name="externalproj">External Projects Using LLVM 2.6</a>
206</div>
207<!-- *********************************************************************** -->
208
Chris Lattnerc32a5322009-09-30 06:27:22 +0000[diff] [blame]209
210<!--=========================================================================-->
211<div class="doc_subsection">
212<a name="macruby">MacRuby</a>
213</div>
214
215<div class="doc_text">
216
217<p>
218<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of
219core Mac OS X technologies, such as the Objective-C common runtime and garbage
220collector, and the CoreFoundation framework. It is principally developed by
221Apple and aims at enabling the creation of full-fledged Mac OS X applications.
222</p>
223
224<p>
225MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby
226expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception
227handling.</p>
228
229</div>
230
231
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]232<!--=========================================================================-->
233<div class="doc_subsection">
234<a name="pure">Pure</a>
235</div>
236
237<div class="doc_text">
238<p>
239<a href="http://pure-lang.googlecode.com/">Pure</a>
240is an algebraic/functional programming language based on term rewriting.
241Programs are collections of equations which are used to evaluate expressions in
242a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
243lexical closures, a hygienic macro system (also based on term rewriting),
244built-in list and matrix support (including list and matrix comprehensions) and
245an easy-to-use C interface. The interpreter uses LLVM as a backend to
246 JIT-compile Pure programs to fast native code.</p>
247
248<p>In addition to the usual algebraic data structures, Pure also has
249MATLAB-style matrices in order to support numeric computations and signal
250processing in an efficient way. Pure is mainly aimed at mathematical
251applications right now, but it has been designed as a general purpose language.
252The dynamic interpreter environment and the C interface make it possible to use
253it as a kind of functional scripting language for many application areas.
254</p>
255</div>
256
257
258<!--=========================================================================-->
259<div class="doc_subsection">
260<a name="ldc">LLVM D Compiler</a>
261</div>
262
263<div class="doc_text">
264<p>
265<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
266the D Programming Language using the LLVM optimizer and code generator.
267The LDC project works great with the LLVM 2.6 release. General improvements in
268this
269cycle have included new inline asm constraint handling, better debug info
270support, general bugfixes, and better x86-64 support. This has allowed
271some major improvements in LDC, getting us much closer to being as
272fully featured as the original DMD compiler from DigitalMars.
273</p>
274</div>
275
276<!--=========================================================================-->
277<div class="doc_subsection">
278<a name="RoadsendPHP">Roadsend PHP</a>
279</div>
280
281<div class="doc_text">
282<p><a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
283source implementation of the PHP programming
284language that uses LLVM for its optimizer, JIT, and static compiler. This is a
285reimplementation of an earlier project that is now based on LLVM.</p>
286</div>
287
Jeffrey Yasskinba2aa782009-06-24 21:09:13 +0000[diff] [blame]288<!--=========================================================================-->
289<div class="doc_subsection">
290<a name="Unladen Swallow">Unladen Swallow</a>
291</div>
292
293<div class="doc_text">
294<p><a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
295branch of <a href="http://python.org/">Python</a> intended to be fully
296compatible and significantly faster. It uses LLVM's optimization passes and JIT
297compiler.</p>
298</div>
299
Jeffrey Yasskin5e98cb72009-06-24 21:26:42 +0000[diff] [blame]300<!--=========================================================================-->
301<div class="doc_subsection">
302<a name="Rubinius">Rubinius</a>
303</div>
304
305<div class="doc_text">
306<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is a new virtual
307machine for Ruby. It leverages LLVM to dynamically compile Ruby code down to
308machine code using LLVM's JIT.</p>
309</div>
310
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]311
312<!-- *********************************************************************** -->
313<div class="doc_section">
314 <a name="whatsnew">What's New in LLVM 2.6?</a>
315</div>
316<!-- *********************************************************************** -->
317
318<div class="doc_text">
319
320<p>This release includes a huge number of bug fixes, performance tweaks, and
321minor improvements. Some of the major improvements and new features are listed
322in this section.
323</p>
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]324
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]325</div>
326
327<!--=========================================================================-->
328<div class="doc_subsection">
329<a name="majorfeatures">Major New Features</a>
330</div>
331
332<div class="doc_text">
333
334<p>LLVM 2.6 includes several major new capabilities:</p>
335
336<ul>
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]337<li>Support for debug line numbers when optimization enabled</li>
338<li>gold lto plugin</li>
339<li>New MSP430 and SystemZ backends.</li>
340<li>New BlackFin backend.</li>
341<li>LLVMContext, llvm_start_multithreaded: ProgrammersManual.html#threading</li>
342<li>Unladen swallow as user?</li>
343<li>klee web page at klee.llvm.org</li>
344<li>FileCheck</li>
345<li>New compiler-rt project.</li>
Edward O'Callaghan50310f92009-08-22 02:17:22 +0000[diff] [blame]346<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]347</ul>
348
349</div>
350
351
352<!--=========================================================================-->
353<div class="doc_subsection">
354<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
355</div>
356
357<div class="doc_text">
358
359<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC
360front-ends and driver with the LLVM optimizer and code generator. It currently
361includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
362
363<ul>
364<li>Something wonderful!</li>
365</ul>
366
367</div>
368
369
370<!--=========================================================================-->
371<div class="doc_subsection">
372<a name="coreimprovements">LLVM IR and Core Improvements</a>
373</div>
374
375<div class="doc_text">
376<p>LLVM IR has several new features that are used by our existing front-ends and
377can be useful if you are writing a front-end for LLVM:</p>
378
379<ul>
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]380<li>Getelementpr instruction now allows any integer type for array/pointer indexes.</li>
381<li>Inbounds for GEP</li>
382<li>NSW/NUW/exact div</li>
383<li>LSR promotes int induction variables to 64-bit on 64-bit targets, major perf boost for numerical code.</li>
384<li>LSR now analyzes pointer expressions (e.g. getelementptrs), not just integers.</li>
385<li>new linkage types linkonce_odr, weak_odr, linker_private, and available_externally.</li>
386<li>New fadd, fsub, fmul instructions and classes. </li>
387<li>Target intrinsics can now return multiple results.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]388</ul>
389
390</div>
391
392<!--=========================================================================-->
393<div class="doc_subsection">
394<a name="optimizer">Optimizer Improvements</a>
395</div>
396
397<div class="doc_text">
398
399<p>In addition to a large array of bug fixes and minor performance tweaks, this
400release includes a few major enhancements and additions to the optimizers:</p>
401
402<ul>
403
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]404<li>SRoA improvements for vector unions, memset, arbitrary weird bitfield accesses etc. It now produces "strange" sized integers.</li>
405<li>Inliner reuse stack space when inlining arrays?</li>
406<li>Enabled GVN Load PRE.</li>
407<li>New Static Single Information (SSI) construction pass (not used by anything yet, experimental).</li>
408</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]409
410</ul>
411
412</div>
413
414<!--=========================================================================-->
415<div class="doc_subsection">
416<a name="codegen">Target Independent Code Generator Improvements</a>
417</div>
418
419<div class="doc_text">
420
421<p>We have put a significant amount of work into the code generator
422infrastructure, which allows us to implement more aggressive algorithms and make
423it run faster:</p>
424
425<ul>
426
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]427<li> -asm-verbose now prints location info (with -g) and loop nest info.</li>
428<li>Tblgen now supports multiclass inheritance and a number of new string and
429 list operations like !(subst), !(foreach), !car, !cdr, !null, !if, !cast.
430 These make the .td files more expressive and allow more aggressive factoring
431 of duplication across instruction patterns.</li>
432<li>New MachineVerifier pass.</li>
433<li>Machine LICM, hoists things like constant pool loads, loads from readonly stubs, vector constant synthesization code, etc.</li>
434<li>Machine Sinking</li>
435<li>target-specific intrinsics (r63765)</li>
436<li>Regalloc improvements for commuting, various spiller peephole optimizations, cross-class coalescing.</li>
437<li><tt>llc -enable-value-prop</tt>, propagation of value info (sign/zero ext info) from one MBB to another</li>
438<li>Regalloc hints for allocation stuff: Evan r73381/r73671. Finished/enabled?</li>
439<li>Stack slot coloring for register spills (denser stack frames)</li>
440<li>SelectionDAGS: New BuildVectorSDNode (r65296), and ISD::VECTOR_SHUFFLE (r69952 / PR2957)</li>
441<li>PostRA scheduler improvements David Goodwin.</li>
442</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]443</ul>
444</div>
445
446<!--=========================================================================-->
447<div class="doc_subsection">
448<a name="x86">X86-32 and X86-64 Target Improvements</a>
449</div>
450
451<div class="doc_text">
452<p>New features of the X86 target include:
453</p>
454
455<ul>
456
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]457<li>Preliminary support for addrspace 256 -> GS, 257 -> FS, known problems: CodeGenerator.html#x86_memory</li>
458<li>Support for softfloat modes, typically used by OS kernels.</li>
459
460<li>X86-64: better modeling of implicit zero extensions, eliminates a lot of redundant zexts</li>
461<li>X86-64 TLS support for local exec and initial exec.</li>
462<li>Better modeling of H registerts as subregs.</li>
463<li>Vector icmp/fcmp now work with SSE codegen.</li>
464<li>SSE 4.2 support.</li>
465<li>all global variable reference logic is now in ClassifyGlobalReference.</li>
466</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]467</ul>
468
469</div>
470
471<!--=========================================================================-->
472<div class="doc_subsection">
473<a name="pic16">PIC16 Target Improvements</a>
474</div>
475
476<div class="doc_text">
477<p>New features of the PIC16 target include:
478</p>
479
480<ul>
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]481<li>Support for floating-point, indirect function calls, and
482 passing/returning aggregate types to functions.
483<li>The code generator is able to generate debug info into output COFF files.
484<li>Support for placing an object into a specific section or at a specific
485 address in memory.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]486</ul>
487
488<p>Things not yet supported:</p>
489
490<ul>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]491<li>Variable arguments.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]492<li>Interrupts/programs.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]493</ul>
494
495</div>
496
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]497<!--=========================================================================-->
498<div class="doc_subsection">
499<a name="ARM">ARM Target Improvements</a>
500</div>
501
502<div class="doc_text">
503<p>New features of the ARM target include:
504</p>
505
506<ul>
507
508<li>Preliminary support for processors, such as the Cortex-A8 and Cortex-A9,
Sandeep Patel64e39612009-08-20 15:01:16 +0000[diff] [blame]509that implement version v7-A of the ARM architecture. The ARM backend now
510supports both the Thumb2 and Advanced SIMD (Neon) instruction sets. The
511AAPCS-VFP "hard float" calling conventions are also supported with the
512<tt>-float-abi=hard</tt> flag. These features are still somewhat experimental
513and subject to change. The Neon intrinsics, in particular, may change in future
514releases of LLVM.
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]515</li>
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]516
517 ARM AAPCS-VFP hard float ABI is supported.
518 ARM calling convention code is now tblgen generated instead of manual.
519 ARM: NEON support. neonfp for doing single precision fp with neon instead of VFP.
520
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]521</ul>
522
523</div>
524
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]525<!--=========================================================================-->
526<div class="doc_subsection">
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]527<a name="OtherTarget">Other Target Specific Improvements</a>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]528</div>
529
530<div class="doc_text">
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]531<p>New features of other targets include:
532</p>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]533
534<ul>
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]535<li>Add support for the PowerPC 64-bit SVR4 ABI.</li>
536<li>Mips now supports O32 Calling Convention.</li>
537</ul>
538
539</div>
540
541<!--=========================================================================-->
542<div class="doc_subsection">
543<a name="newapis">New Useful APIs</a>
544</div>
545
546<div class="doc_text">
547
548<ul>
549<li>New EngineBuilder class for creating JITs: r76276</li>
550 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.
551 StringRef class, Twine class.
552 New WeakVH and AssertingVH and CallbackVH classes.
553 New llvm/ADT/Triple class.
554 llvm_report_error() error handling API (llvm/Support/ErrorHandling.h)
555 New llvm/System/Atomic.h, llvm/System/RWMutex.h for portable atomic ops, rw locks.
556 New SourceMgr, SMLoc classes for simple parsers with caret diagnostics and #include support, (used by
557 tablegen, llvm-mc, the .ll parser, FileCheck, etc)
558
559<ul>
560
561
562</div>
563
564<!--=========================================================================-->
565<div class="doc_subsection">
566<a name="otherimprovements">Other Improvements and New Features</a>
567</div>
568
569<div class="doc_text">
570<p>Other miscellaneous features include:</p>
571
572<ul>
573<li>interpreter + libffi</li>
574<li> JIT now supports generating more than 16M of code.</li>
575<li>Users can now <a
576href="http://llvm.org/doxygen/classllvm_1_1ExecutionEngine.html#fcd2b4b92ca38812ca31640b0da14927">register</a>
577a <a href="http://llvm.org/doxygen/classllvm_1_1JITEventListener.html">JITEventListener</a>
578to receive callbacks when the JIT emits or frees machine code. The
579OProfile support uses this mechanism.</li>
580 JIT support for oprofile (r75279), configure with --with-oprofile. Now we get line # and function info for JIT'd functions.
581
582<li> Profile info improvements by Andreas Neustifter.</li>
583<li> Many extensions to the C APIs.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]584</ul>
585
586</div>
587
588
589<!--=========================================================================-->
590<div class="doc_subsection">
591<a name="changes">Major Changes and Removed Features</a>
592</div>
593
594<div class="doc_text">
595
596<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]597on LLVM 2.5, this section lists some "gotchas" that you may run into upgrading
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]598from the previous release.</p>
599
600<ul>
601
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]602<li>The Itanium (IA64) backend has been removed. It was not supported and
603 bitrotted.</li>
604<li>The BigBlock register allocator has been removed, it also bitrotted.</li>
605<li>The C Backend (-march=c) is no longer considered part of the LLVM release
606criteria. We still want it to work, but no one is maintaining it and it lacks
607support for arbitrary precision integers and other important IR features.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]608</ul>
609
610
611<p>In addition, many APIs have changed in this release. Some of the major LLVM
612API changes are:</p>
613
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]614
615 API Cleanup:
616 no use of hash_set/hash_map, no more llvm::OStream
617 Use raw_ostream for everything, killed off llvm/Streams.h and DOUT
618
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]619<ul>
Owen Andersone27be3a2009-07-02 16:48:38 +0000[diff] [blame]620<li>LLVM's global uniquing tables for <tt>Type</tt>s and <tt>Constant</tt>s have
621 been privatized into members of an <tt>LLVMContext</tt>. A number of APIs
622 now take an <tt>LLVMContext</tt> as a parameter. To smooth the transition
623 for clients that will only ever use a single context, the new
624 <tt>getGlobalContext()</tt> API can be used to access a default global
625 context which can be passed in any and all cases where a context is
626 required.
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]627<li>The <tt>getABITypeSize</tt> methods are now called <tt>getAllocSize</tt>.</li>
Dan Gohmanf667e7e2009-07-07 20:05:15 +0000[diff] [blame]628<li>The <tt>Add</tt>, <tt>Sub</tt>, and <tt>Mul</tt> operators are no longer
629 overloaded for floating-point types. Floating-point addition, subtraction,
630 and multiplication are now represented with new operators <tt>FAdd</tt>,
631 <tt>FSub</tt>, and <tt>FMul</tt>. In the <tt>IRBuilder</tt> API,
632 <tt>CreateAdd</tt>, <tt>CreateSub</tt>, <tt>CreateMul</tt>, and
633 <tt>CreateNeg</tt> should only be used for integer arithmetic now;
634 <tt>CreateFAdd</tt>, <tt>CreateFSub</tt>, <tt>CreateFMul</tt>, and
635 <tt>CreateFNeg</tt> should now be used for floating-point arithmetic.</li>
Daniel Dunbar02e73132009-07-12 20:41:27 +0000[diff] [blame]636<li>The DynamicLibrary class can no longer be constructed, its functionality has
637 moved to static member functions.</li>
Dan Gohmane4d54d72009-07-15 19:59:19 +0000[diff] [blame]638<li><tt>raw_fd_ostream</tt>'s constructor for opening a given filename now
639 takes an extra <tt>Force</tt> argument. If <tt>Force</tt> is set to
640 <tt>false</tt>, an error will be reported if a file with the given name
641 already exists. If <tt>Force</tt> is set to <tt>true</tt>, the file will
642 be silently truncated (which is the behavior before this flag was
643 added).</li>
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]644<li><tt>SCEVHandle</tt> no longer exists, because reference counting is no
645longer done for <tt>SCEV*</tt> objects, instead <tt>const SCEV*</tt> should be
646used.</li>
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]647
Daniel Dunbar6e0d1cb2009-07-25 04:41:11 +0000[diff] [blame]648<li>Many APIs, notably <tt>llvm::Value</tt>, now use the <tt>StringRef</tt>
649and <tt>Twine</tt> classes instead of passing <tt>const char*</tt>
650or <tt>std::string</tt>, as described in
651the <a href="ProgrammersManual.html#string_apis">Programmer's Manual</a>. Most
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]652clients 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:
653 <ul>
654 <li><tt>getNameStr()</tt> is still available, and matches the old
655 behavior. Replacing <tt>getName()</tt> calls with this is an safe option,
656 although more efficient alternatives are now possible.</li>
657
658 <li>If you were just relying on <tt>getName()</tt> being able to be sent to
659 a <tt>std::ostream</tt>, consider migrating
660 to <tt>llvm::raw_ostream</tt>.</li>
661
662 <li>If you were using <tt>getName().c_str()</tt> to get a <tt>const
663 char*</tt> pointer to the name, you can use <tt>getName().data()</tt>.
664 Note that this string (as before), may not be the entire name if the
665 name containts embedded null characters.</li>
666
667 <li>If you were using operator plus on the result of <tt>getName()</tt> and
668 treating the result as an <tt>std::string</tt>, you can either
669 uses <tt>Twine::str</tt> to get the result as an <tt>std::string</tt>, or
670 could move to a <tt>Twine</tt> based design.</li>
Daniel Dunbar03d76512009-07-25 23:55:21 +0000[diff] [blame]671
672 <li><tt>isName()</tt> should be replaced with comparison
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]673 against <tt>getName()</tt> (this is now efficient).
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]674 </ul>
675</li>
676
Daniel Dunbara5881e32009-07-26 02:12:58 +0000[diff] [blame]677<li>The registration interfaces for backend Targets has changed (what was
Daniel Dunbard6b06b12009-07-26 05:41:39 +0000[diff] [blame]678previously TargetMachineRegistry). For backend authors, see the <a href="WritingAnLLVMBackend.html#TargetRegistration">Writing An LLVM Backend</a> guide. For clients, the notable API changes are:
679 <ul>
680 <li><tt>TargetMachineRegistry</tt> has been renamed
681 to <tt>TargetRegistry</tt>.</li>
682
683 <li>Clients should move to using the <tt>TargetRegistry::lookupTarget()</tt>
684 function to find targets.</li>
685 </ul>
686</li>
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]687
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]688<li>llvm-dis now fails if output file exists, instead of dumping to stdout.
Daniel Dunbar6e0d1cb2009-07-25 04:41:11 +0000[diff] [blame]689FIXME: describe any other tool changes due to the raw_fd_ostream change. FIXME:
690This is not an API change, maybe there should be a tool changes section?</li>
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]691<li>temporarely due to Context API change passes should call doInitialization()
692method of the pass they inherit from, otherwise Context is NULL.
693FIXME: remove this entry when this is no longer needed.<li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]694</ul>
695
696</div>
697
698
699
700<!-- *********************************************************************** -->
701<div class="doc_section">
702 <a name="portability">Portability and Supported Platforms</a>
703</div>
704<!-- *********************************************************************** -->
705
706<div class="doc_text">
707
708<p>LLVM is known to work on the following platforms:</p>
709
710<ul>
711<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]712Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like systems).</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]713<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
714and 64-bit modes.</li>
715<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
716<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
717 support is available for native builds with Visual C++).</li>
718<li>Sun UltraSPARC workstations running Solaris 10.</li>
719<li>Alpha-based machines running Debian GNU/Linux.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]720</ul>
721
722<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
723to the machine and operating system on which it is built. However, minor
724porting may be required to get LLVM to work on new platforms. We welcome your
725portability patches and reports of successful builds or error messages.</p>
726
727</div>
728
729<!-- *********************************************************************** -->
730<div class="doc_section">
731 <a name="knownproblems">Known Problems</a>
732</div>
733<!-- *********************************************************************** -->
734
735<div class="doc_text">
736
737<p>This section contains significant known problems with the LLVM system,
738listed by component. If you run into a problem, please check the <a
739href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
740there isn't already one.</p>
741
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]742<ul>
Chris Lattneraedb59a2009-07-21 23:17:26 +0000[diff] [blame]743<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]744using the stock GCC 3.x.x series 'out the box',
745See: <a href="#brokengcc">Broken versions of GCC and other tools</a>.
746However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
747for x86/x64 has been made available from the third party AuroraUX Project
Chris Lattner7b0a6812009-10-08 06:27:53 +0000[diff] [blame^]748that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]749</ul>
750
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]751</div>
752
753<!-- ======================================================================= -->
754<div class="doc_subsection">
755 <a name="experimental">Experimental features included with this release</a>
756</div>
757
758<div class="doc_text">
759
760<p>The following components of this LLVM release are either untested, known to
761be broken or unreliable, or are in early development. These components should
762not be relied on, and bugs should not be filed against them, but they may be
763useful to some people. In particular, if you would like to work on one of these
764components, please contact us on the <a
765href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
766
767<ul>
Dan Gohmand2cb3d22009-07-24 00:30:09 +0000[diff] [blame]768<li>The MSIL, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]769<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
770 supported value for this option.</li>
771</ul>
772
773</div>
774
775<!-- ======================================================================= -->
776<div class="doc_subsection">
777 <a name="x86-be">Known problems with the X86 back-end</a>
778</div>
779
780<div class="doc_text">
781
782<ul>
783 <li>The X86 backend does not yet support
784 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
785 floating point stack</a>. It supports the 'f' and 't' constraints, but not
786 'u'.</li>
787 <li>The X86 backend generates inefficient floating point code when configured
788 to generate code for systems that don't have SSE2.</li>
789 <li>Win64 code generation wasn't widely tested. Everything should work, but we
790 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
791 runtime currently due
792 to <a href="http://llvm.org/PR2255">several</a>
793 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
794 the
795 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
796 <li>The X86-64 backend does not yet support the LLVM IR instruction
797 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
798 argument constructs on X86-64 by lowering them manually.</li>
799</ul>
800
801</div>
802
803<!-- ======================================================================= -->
804<div class="doc_subsection">
805 <a name="ppc-be">Known problems with the PowerPC back-end</a>
806</div>
807
808<div class="doc_text">
809
810<ul>
811<li>The Linux PPC32/ABI support needs testing for the interpreter and static
812compilation, and lacks support for debug information.</li>
813</ul>
814
815</div>
816
817<!-- ======================================================================= -->
818<div class="doc_subsection">
819 <a name="arm-be">Known problems with the ARM back-end</a>
820</div>
821
822<div class="doc_text">
823
824<ul>
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]825<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
826and not well tested. Some features may not work at all, and the code quality
827may be poor in some cases.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]828<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
829processors, thumb programs can crash or produce wrong
830results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
831<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
832</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]833</ul>
834
835</div>
836
837<!-- ======================================================================= -->
838<div class="doc_subsection">
839 <a name="sparc-be">Known problems with the SPARC back-end</a>
840</div>
841
842<div class="doc_text">
843
844<ul>
845<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
846 support the 64-bit SPARC ABI (-m64).</li>
847</ul>
848
849</div>
850
851<!-- ======================================================================= -->
852<div class="doc_subsection">
853 <a name="mips-be">Known problems with the MIPS back-end</a>
854</div>
855
856<div class="doc_text">
857
858<ul>
859<li>The O32 ABI is not fully supported.</li>
860<li>64-bit MIPS targets are not supported yet.</li>
861</ul>
862
863</div>
864
865<!-- ======================================================================= -->
866<div class="doc_subsection">
867 <a name="alpha-be">Known problems with the Alpha back-end</a>
868</div>
869
870<div class="doc_text">
871
872<ul>
873
874<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
875appropriate nops inserted to ensure restartability.</li>
876
877</ul>
878</div>
879
880<!-- ======================================================================= -->
881<div class="doc_subsection">
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]882 <a name="c-be">Known problems with the C back-end</a>
883</div>
884
885<div class="doc_text">
886
887<ul>
888<li><a href="http://llvm.org/PR802">The C backend has only basic support for
889 inline assembly code</a>.</li>
890<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
891 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
892 C++ code compiled with <tt>llc</tt> or native compilers.</li>
893<li>The C backend does not support all exception handling constructs.</li>
894<li>The C backend does not support arbitrary precision integers.</li>
895</ul>
896
897</div>
898
899
900<!-- ======================================================================= -->
901<div class="doc_subsection">
902 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
903</div>
904
905<div class="doc_text">
906
907<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
908Optimization</a> on most platforms "out-of-the-box". Please inquire on the
909LLVMdev mailing list if you are interested.</p>
910
911<p>The only major language feature of GCC not supported by llvm-gcc is
912 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
913 are only supported on some targets. For example, trampolines are only
914 supported on some targets (these are used when you take the address of a
915 nested function).</p>
916
917<p>If you run into GCC extensions which are not supported, please let us know.
918</p>
919
920</div>
921
922<!-- ======================================================================= -->
923<div class="doc_subsection">
924 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
925</div>
926
927<div class="doc_text">
928
929<p>The C++ front-end is considered to be fully
930tested and works for a number of non-trivial programs, including LLVM
931itself, Qt, Mozilla, etc.</p>
932
933<ul>
934<li>Exception handling works well on the X86 and PowerPC targets. Currently
935 only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
936</ul>
937
938</div>
939
940<!-- ======================================================================= -->
941<div class="doc_subsection">
942 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
943</div>
944
945<div class="doc_text">
946<ul>
947<li>Fortran support generally works, but there are still several unresolved bugs
948 in Bugzilla. Please see the tools/gfortran component for details.</li>
949</ul>
950</div>
951
952<!-- ======================================================================= -->
953<div class="doc_subsection">
954 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
955</div>
956
957<div class="doc_text">
958The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
959technology, and problems should be expected.
960<ul>
961<li>The Ada front-end currently only builds on X86-32. This is mainly due
962to lack of trampoline support (pointers to nested functions) on other platforms.
963However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
964which does support trampolines.</li>
965<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
966This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
967exception handling, which is used internally by the compiler.
968Workaround: configure with --disable-bootstrap.</li>
969<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
970and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
971(c380004 also fails with gcc-4.2 mainline).
972If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
973causes the compiler to go into an infinite loop, using up all system memory.</li>
974<li>Some GCC specific Ada tests continue to crash the compiler.</li>
975<li>The -E binder option (exception backtraces)
976<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
977crashing if an exception is raised. Workaround: do not use -E.</li>
978<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
979or finish at a non-byte offset</a> in a record. Workaround: do not pack records
980or use representation clauses that result in a field of a non-discrete type
981starting or finishing in the middle of a byte.</li>
982<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
983'main' as generated by the Ada binder to be invalid</a>.
984Workaround: hand edit the file to use pointers for <tt>argv</tt> and
985<tt>envp</tt> rather than integers.</li>
986<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
987ignored</a>.</li>
988</ul>
989</div>
990
Erick Tryzelaar17167be2009-09-28 04:42:55 +0000[diff] [blame]991<!-- ======================================================================= -->
992<div class="doc_subsection">
993 <a name="ocaml-bindingse">Known problems with the O'Caml bindings</a>
994</div>
995
996<div class="doc_text">
997
998<p>The Llvm.Linkage module is broken, and has incorrect values. Only
999Llvm.Linkage.External, Llvm.Linkage.Available_externally, and
1000Llvm.Linkage.Link_once will be correct. If you need any of the other linkage
1001modes, you'll have to write an external C library in order to expose the
1002functionality. This has been fixed in the trunk.</p>
1003</div>
1004
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]1005<!-- *********************************************************************** -->
1006<div class="doc_section">
1007 <a name="additionalinfo">Additional Information</a>
1008</div>
1009<!-- *********************************************************************** -->
1010
1011<div class="doc_text">
1012
1013<p>A wide variety of additional information is available on the <a
1014href="http://llvm.org">LLVM web page</a>, in particular in the <a
1015href="http://llvm.org/docs/">documentation</a> section. The web page also
1016contains versions of the API documentation which is up-to-date with the
1017Subversion version of the source code.
1018You can access versions of these documents specific to this release by going
1019into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
1020
1021<p>If you have any questions or comments about LLVM, please feel free to contact
1022us via the <a href="http://llvm.org/docs/#maillist"> mailing
1023lists</a>.</p>
1024
1025</div>
1026
1027<!-- *********************************************************************** -->
1028
1029<hr>
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