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7 <title>LLVM 2.8 Release Notes</title>
11 <div class="doc_title">LLVM 2.8 Release Notes</div>
13 <img align=right src="http://llvm.org/img/DragonSmall.png"
14 width="136" height="136" alt="LLVM Dragon Logo">
17 <li><a href="#intro">Introduction</a></li>
18 <li><a href="#subproj">Sub-project Status Update</a></li>
19 <li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
20 <li><a href="#whatsnew">What's New in LLVM 2.8?</a></li>
21 <li><a href="GettingStarted.html">Installation Instructions</a></li>
22 <li><a href="#knownproblems">Known Problems</a></li>
23 <li><a href="#additionalinfo">Additional Information</a></li>
26 <div class="doc_author">
27 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
31 <h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
34 <a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
35 Release Notes</a>.</h1>
38 <!-- *********************************************************************** -->
39 <div class="doc_section">
40 <a name="intro">Introduction</a>
42 <!-- *********************************************************************** -->
44 <div class="doc_text">
46 <p>This document contains the release notes for the LLVM Compiler
47 Infrastructure, release 2.8. Here we describe the status of LLVM, including
48 major improvements from the previous release and significant known problems.
49 All LLVM releases may be downloaded from the <a
50 href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
52 <p>For more information about LLVM, including information about the latest
53 release, please check out the <a href="http://llvm.org/">main LLVM
54 web site</a>. If you have questions or comments, the <a
55 href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
56 Mailing List</a> is a good place to send them.</p>
58 <p>Note that if you are reading this file from a Subversion checkout or the
59 main LLVM web page, this document applies to the <i>next</i> release, not the
60 current one. To see the release notes for a specific release, please see the
61 <a href="http://llvm.org/releases/">releases page</a>.</p>
68 include/llvm/Analysis/LiveValues.h => Dan
69 lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
70 llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
75 <!-- Features that need text if they're finished for 2.9:
78 loop dependence analysis
80 CorrelatedValuePropagation
83 <!-- Announcement, lldb, libc++ -->
86 MachineCSE tuned and on by default.
87 llvm.dbg.value: variable debug info for optimized code
88 MC Assembler backend is now real, does relaxation and is bitwise identical
89 with darwin assembler in huge majority of all cases.
90 new GHC calling convention
91 New half float intrinsics LangRef.html#int_fp16
92 Rewrote tblgen's type inference for backends to be more consistent and
93 diagnose more target bugs. This also allows limited support for writing
94 patterns for instructions that return multiple results, e.g. a virtual
95 register and a flag result. Stuff that used 'parallel' before should use
97 New ARM/Thumb disassembler support in MC.
98 New SSEDomainFix pass:
99 On Nehalem and newer CPUs there is a 2 cycle latency penalty on using a
100 register in a different domain than where it was defined. Some instructions
101 have equvivalents for different domains, like por/orps/orpd. The
102 SSEDomainFix pass tries to minimize the number of domain crossings by
103 changing between equvivalent opcodes where possible.
104 Support for the Intel AES instructions in the assembler.
105 memcpy, memmove, and memset now take address space qualified pointers + volatile.
110 <!-- *********************************************************************** -->
111 <div class="doc_section">
112 <a name="subproj">Sub-project Status Update</a>
114 <!-- *********************************************************************** -->
116 <div class="doc_text">
118 The LLVM 2.8 distribution currently consists of code from the core LLVM
119 repository (which roughly includes the LLVM optimizers, code generators
120 and supporting tools), the Clang repository and the llvm-gcc repository. In
121 addition to this code, the LLVM Project includes other sub-projects that are in
122 development. Here we include updates on these subprojects.
128 <!--=========================================================================-->
129 <div class="doc_subsection">
130 <a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
133 <div class="doc_text">
135 <p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
136 C++, and Objective-C languages. Clang aims to provide a better user experience
137 through expressive diagnostics, a high level of conformance to language
138 standards, fast compilation, and low memory use. Like LLVM, Clang provides a
139 modular, library-based architecture that makes it suitable for creating or
140 integrating with other development tools. Clang is considered a
141 production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
142 (32- and 64-bit), and for darwin-arm targets.</p>
144 <p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
147 <li>Surely these guys have done something</li>
151 <!--=========================================================================-->
152 <div class="doc_subsection">
153 <a name="clangsa">Clang Static Analyzer</a>
156 <div class="doc_text">
158 <p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
159 project is an effort to use static source code analysis techniques to
160 automatically find bugs in C and Objective-C programs (and hopefully <a
161 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
162 future</a>!). The tool is very good at finding bugs that occur on specific
163 paths through code, such as on error conditions.</p>
165 <p>In the LLVM 2.8 time-frame,
170 <!--=========================================================================-->
171 <div class="doc_subsection">
172 <a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
175 <div class="doc_text">
177 The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
178 a JVM and a CLI Virtual Machine (Microsoft .NET is an
179 implementation of the CLI) using LLVM for static and just-in-time
182 <p>With the release of LLVM 2.8, ...</p>
187 <!--=========================================================================-->
188 <div class="doc_subsection">
189 <a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
192 <div class="doc_text">
194 The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
195 is a simple library that provides an implementation of the low-level
196 target-specific hooks required by code generation and other runtime components.
197 For example, when compiling for a 32-bit target, converting a double to a 64-bit
198 unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
199 function. The compiler-rt library provides highly optimized implementations of
200 this and other low-level routines (some are 3x faster than the equivalent
201 libgcc routines).</p>
204 All of the code in the compiler-rt project is available under the standard LLVM
205 License, a "BSD-style" license. New in LLVM 2.8:
212 <!--=========================================================================-->
213 <div class="doc_subsection">
214 <a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
217 <div class="doc_text">
219 <a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
220 gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
221 gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
222 whatsoever (currently one small patch is needed). This is thanks to the new
223 <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
224 makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
225 which is nothing more than a dynamic library which conforms to the gcc plugin
226 interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
227 instead of the gcc optimizers, and the LLVM code generators instead of the gcc
228 code generators, just like llvm-gcc. To use it, you add
229 "-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
230 becomes llvm-gcc-4.5!
234 DragonEgg is still a work in progress. Currently C works very well, while C++,
235 Ada and Fortran work fairly well. All other languages either don't work at all,
236 or only work poorly. For the moment only the x86-32 and x86-64 targets are
237 supported, and only on linux and darwin (darwin needs an additional gcc patch).
247 <!--=========================================================================-->
248 <div class="doc_subsection">
249 <a name="mc">llvm-mc: Machine Code Toolkit</a>
252 <div class="doc_text">
254 The LLVM Machine Code (aka MC) sub-project of LLVM was created to solve a number
255 of problems in the realm of assembly, disassembly, object file format handling,
256 and a number of other related areas that CPU instruction-set level tools work
257 in. It is a sub-project of LLVM which provides it with a number of advantages
258 over other compilers that do not have tightly integrated assembly-level tools.
259 For a gentle introduction, please see the <a
260 href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
261 LLVM MC Project Blog Post</a>.
264 <p>2.8 status here. Basic correctness, some obscure missing instructions on
265 mainline, on by default in clang.
266 Entire compiler backend converted to use mcstreamer.
270 <!--=========================================================================-->
271 <div class="doc_subsection">
272 <a name="lldb">LLDB: Low Level Debugger</a>
275 <div class="doc_text">
277 <a href="http://lldb.llvm.org/">LLDB</a> is</p>
288 <!--=========================================================================-->
289 <div class="doc_subsection">
290 <a name="libc++">libc++: C++ Standard Library</a>
293 <div class="doc_text">
295 <a href="http://libc++.llvm.org/">libc++</a> is</p>
307 <!-- *********************************************************************** -->
308 <div class="doc_section">
309 <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
311 <!-- *********************************************************************** -->
313 <div class="doc_text">
315 <p>An exciting aspect of LLVM is that it is used as an enabling technology for
316 a lot of other language and tools projects. This section lists some of the
317 projects that have already been updated to work with LLVM 2.8.</p>
321 <!-- *********************************************************************** -->
322 <div class="doc_section">
323 <a name="whatsnew">What's New in LLVM 2.8?</a>
325 <!-- *********************************************************************** -->
327 <div class="doc_text">
329 <p>This release includes a huge number of bug fixes, performance tweaks and
330 minor improvements. Some of the major improvements and new features are listed
336 <!--=========================================================================-->
337 <div class="doc_subsection">
338 <a name="orgchanges">LLVM Community Changes</a>
341 <div class="doc_text">
343 <p>In addition to changes to the code, between LLVM 2.7 and 2.8, a number of
344 organization changes have happened:
348 <li>libc++ and lldb are new</li>
349 <li>Debugging optimized code support.</li>
353 <!--=========================================================================-->
354 <div class="doc_subsection">
355 <a name="majorfeatures">Major New Features</a>
358 <div class="doc_text">
360 <p>LLVM 2.8 includes several major new capabilities:</p>
363 <li>atomic lowering pass.</li>
364 <li>RegionInfo pass: opt -regions analyze" or "opt -view-regions".
365 <!-- Tobias Grosser --></li>
366 <li>ARMGlobalMerge: <!-- Anton --> </li>
372 <!--=========================================================================-->
373 <div class="doc_subsection">
374 <a name="coreimprovements">LLVM IR and Core Improvements</a>
377 <div class="doc_text">
378 <p>LLVM IR has several new features for better support of new targets and that
379 expose new optimization opportunities:</p>
383 <li>LLVM 2.8 changes the internal order of operands in <a
384 href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
385 and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
386 To be portable across releases, resort to <tt>CallSite</tt> and the
387 high-level accessors, such as <tt>getCalledValue</tt> and <tt>setUnwindDest</tt>.
390 You can no longer pass use_iterators directly to cast<> (and similar), because
391 these routines tend to perform costly dereference operations more than once. You
392 have to dereference the iterators yourself and pass them in.
395 llvm.memcpy.*, llvm.memset.*, llvm.memmove.* (and possibly other?) intrinsics
396 take an extra parameter now (i1 isVolatile), totaling 5 parameters.
397 If you were creating these intrinsic calls and prototypes yourself (as opposed
398 to using Intrinsic::getDeclaration), you can use UpgradeIntrinsicFunction/UpgradeIntrinsicCall
399 to be portable accross releases.
400 Note that you cannot use Intrinsic::getDeclaration() in a backwards compatible
401 way (needs 2/3 types now, in 2.7 it needed just 1).
404 SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
405 Change your code to use
406 SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
409 VISIBILITY_HIDDEN is gone.
412 The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
413 considered deprecated, but continue to function in LLVM 2.8. Clients are
414 strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
415 <tt>INITIALIZE_AG_PASS()</tt> macros instead.
417 SMDiagnostic takes different parameters now. //FIXME: how to upgrade?
420 The constructor for the Triple class no longer tries to understand odd triple
421 specifications. Frontends should ensure that they only pass valid triples to
422 LLVM. The Triple::normalize utility method has been added to help front-ends
423 deal with funky triples.
425 Some APIs got renamed:
427 <li>llvm_report_error -> report_fatal_error</li>
428 <li>llvm_install_error_handler -> install_fatal_error_handler</li>
429 <li>llvm::DwarfExceptionHandling -> llvm::JITExceptionHandling</li>
436 <!--=========================================================================-->
437 <div class="doc_subsection">
438 <a name="optimizer">Optimizer Improvements</a>
441 <div class="doc_text">
443 <p>In addition to a large array of minor performance tweaks and bug fixes, this
444 release includes a few major enhancements and additions to the optimizers:</p>
455 <!--=========================================================================-->
456 <div class="doc_subsection">
457 <a name="executionengine">Interpreter and JIT Improvements</a>
460 <div class="doc_text">
469 <!--=========================================================================-->
470 <div class="doc_subsection">
471 <a name="codegen">Target Independent Code Generator Improvements</a>
474 <div class="doc_text">
476 <p>We have put a significant amount of work into the code generator
477 infrastructure, which allows us to implement more aggressive algorithms and make
481 <li>MachO writer works.</li>
485 <!--=========================================================================-->
486 <div class="doc_subsection">
487 <a name="x86">X86-32 and X86-64 Target Improvements</a>
490 <div class="doc_text">
491 <p>New features of the X86 target include:
495 <li>The X86 backend now supports holding X87 floating point stack values
496 in registers across basic blocks, dramatically improving performance of code
497 that uses long double, and when targetting CPUs that don't support SSE.</li>
503 <!--=========================================================================-->
504 <div class="doc_subsection">
505 <a name="ARM">ARM Target Improvements</a>
508 <div class="doc_text">
509 <p>New features of the ARM target include:
515 All of the NEON load and store intrinsics (llvm.arm.neon.vld* and
516 llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes
517 of the memory being accessed.
520 The llvm.arm.neon.vaba intrinsic (vector absolute difference and
521 accumulate) has been removed. This operation is now represented using
522 the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a
526 The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening
527 vector absolute difference with and without accumlation) have been removed.
528 They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute
529 difference) followed by a vector zero-extend operation, and for vabal,
533 The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic
534 are now replaced by vector truncate operations.
537 The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been
538 removed. They are now represented as vector sign-extend (vmovls) and
539 zero-extend (vmovlu) operations.
542 The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and
543 llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have
544 been removed. They are replaced by vector add and vector subtract operations
545 where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either
546 sign-extended or zero-extended.
549 The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and
550 llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without
551 accumulation and subtraction) have been removed. These operations are now
552 represented as vector multiplications where the operands are either
553 sign-extended or zero-extended, followed by a vector add for vmlal or a
554 vector subtract for vmlsl. Note that the polynomial vector multiply
555 intrinsic, llvm.arm.neon.vmullp, remains unchanged.
561 <!--=========================================================================-->
562 <div class="doc_subsection">
563 <a name="newapis">New Useful APIs</a>
566 <div class="doc_text">
568 <p>This release includes a number of new APIs that are used internally, which
569 may also be useful for external clients.
579 <!--=========================================================================-->
580 <div class="doc_subsection">
581 <a name="otherimprovements">Other Improvements and New Features</a>
584 <div class="doc_text">
585 <p>Other miscellaneous features include:</p>
594 <!--=========================================================================-->
595 <div class="doc_subsection">
596 <a name="changes">Major Changes and Removed Features</a>
599 <div class="doc_text">
601 <p>If you're already an LLVM user or developer with out-of-tree changes based
602 on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
603 from the previous release.</p>
606 <li>.ll file doesn't produce #uses comments anymore, to get them, run a .bc file
607 through "llvm-dis --show-annotations".</li>
608 <li>MSIL Backend removed.</li>
609 <li>ABCD and SSI passes removed.</li>
610 <li>'Union' LLVM IR feature removed.</li>
613 <p>In addition, many APIs have changed in this release. Some of the major LLVM
622 <!-- *********************************************************************** -->
623 <div class="doc_section">
624 <a name="knownproblems">Known Problems</a>
626 <!-- *********************************************************************** -->
628 <div class="doc_text">
630 <p>This section contains significant known problems with the LLVM system,
631 listed by component. If you run into a problem, please check the <a
632 href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
633 there isn't already one.</p>
637 <!-- ======================================================================= -->
638 <div class="doc_subsection">
639 <a name="experimental">Experimental features included with this release</a>
642 <div class="doc_text">
644 <p>The following components of this LLVM release are either untested, known to
645 be broken or unreliable, or are in early development. These components should
646 not be relied on, and bugs should not be filed against them, but they may be
647 useful to some people. In particular, if you would like to work on one of these
648 components, please contact us on the <a
649 href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
652 <li>The Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
653 backends are experimental.</li>
654 <li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
655 supported value for this option. XXX Update me</li>
660 <!-- ======================================================================= -->
661 <div class="doc_subsection">
662 <a name="x86-be">Known problems with the X86 back-end</a>
665 <div class="doc_text">
668 <li>The X86 backend does not yet support
669 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
670 floating point stack</a>. It supports the 'f' and 't' constraints, but not
672 <li>Win64 code generation wasn't widely tested. Everything should work, but we
673 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
674 runtime currently due to lack of support for the 'u' inline assembly
675 constraint and for X87 floating point inline assembly.</li>
676 <li>The X86-64 backend does not yet support the LLVM IR instruction
677 <tt>va_arg</tt>. Currently, front-ends support variadic
678 argument constructs on X86-64 by lowering them manually.</li>
683 <!-- ======================================================================= -->
684 <div class="doc_subsection">
685 <a name="ppc-be">Known problems with the PowerPC back-end</a>
688 <div class="doc_text">
691 <li>The Linux PPC32/ABI support needs testing for the interpreter and static
692 compilation, and lacks support for debug information.</li>
697 <!-- ======================================================================= -->
698 <div class="doc_subsection">
699 <a name="arm-be">Known problems with the ARM back-end</a>
702 <div class="doc_text">
705 <li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
706 processors, thumb programs can crash or produce wrong
707 results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
708 <li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
714 <!-- ======================================================================= -->
715 <div class="doc_subsection">
716 <a name="sparc-be">Known problems with the SPARC back-end</a>
719 <div class="doc_text">
722 <li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
723 support the 64-bit SPARC ABI (-m64).</li>
728 <!-- ======================================================================= -->
729 <div class="doc_subsection">
730 <a name="mips-be">Known problems with the MIPS back-end</a>
733 <div class="doc_text">
736 <li>64-bit MIPS targets are not supported yet.</li>
741 <!-- ======================================================================= -->
742 <div class="doc_subsection">
743 <a name="alpha-be">Known problems with the Alpha back-end</a>
746 <div class="doc_text">
750 <li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
751 appropriate nops inserted to ensure restartability.</li>
756 <!-- ======================================================================= -->
757 <div class="doc_subsection">
758 <a name="c-be">Known problems with the C back-end</a>
761 <div class="doc_text">
763 <p>The C backend has numerous problems and is not being actively maintained.
764 Depending on it for anything serious is not advised.</p>
767 <li><a href="http://llvm.org/PR802">The C backend has only basic support for
768 inline assembly code</a>.</li>
769 <li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
770 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
771 C++ code compiled with <tt>llc</tt> or native compilers.</li>
772 <li>The C backend does not support all exception handling constructs.</li>
773 <li>The C backend does not support arbitrary precision integers.</li>
779 <!-- ======================================================================= -->
780 <div class="doc_subsection">
781 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
784 <div class="doc_text">
786 <p>llvm-gcc is generally very stable for the C family of languages. The only
787 major language feature of GCC not supported by llvm-gcc is the
788 <tt>__builtin_apply</tt> family of builtins. However, some extensions
789 are only supported on some targets. For example, trampolines are only
790 supported on some targets (these are used when you take the address of a
791 nested function).</p>
793 <p>Fortran support generally works, but there are still several unresolved bugs
794 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
795 tools/gfortran component for details. Note that llvm-gcc is missing major
796 Fortran performance work in the frontend and library that went into GCC after
797 4.2. If you are interested in Fortran, we recommend that you consider using
798 <a href="#dragonegg">dragonegg</a> instead.</p>
800 <p>The llvm-gcc 4.2 Ada compiler has basic functionality. However, this is not a
801 mature technology, and problems should be expected. For example:</p>
803 <li>The Ada front-end currently only builds on X86-32. This is mainly due
804 to lack of trampoline support (pointers to nested functions) on other platforms.
805 However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
806 which does support trampolines.</li>
807 <li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
808 This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
809 exception handling, which is used internally by the compiler.
810 Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
811 <li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
812 and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
813 (c380004 also fails with gcc-4.2 mainline).
814 If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
815 causes the compiler to go into an infinite loop, using up all system memory.</li>
816 <li>Some GCC specific Ada tests continue to crash the compiler.</li>
817 <li>The <tt>-E</tt> binder option (exception backtraces)
818 <a href="http://llvm.org/PR1982">does not work</a> and will result in programs
819 crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
820 <li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
821 or finish at a non-byte offset</a> in a record. Workaround: do not pack records
822 or use representation clauses that result in a field of a non-discrete type
823 starting or finishing in the middle of a byte.</li>
824 <li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
825 'main' as generated by the Ada binder to be invalid</a>.
826 Workaround: hand edit the file to use pointers for <tt>argv</tt> and
827 <tt>envp</tt> rather than integers.</li>
828 <li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
833 <!-- *********************************************************************** -->
834 <div class="doc_section">
835 <a name="additionalinfo">Additional Information</a>
837 <!-- *********************************************************************** -->
839 <div class="doc_text">
841 <p>A wide variety of additional information is available on the <a
842 href="http://llvm.org">LLVM web page</a>, in particular in the <a
843 href="http://llvm.org/docs/">documentation</a> section. The web page also
844 contains versions of the API documentation which is up-to-date with the
845 Subversion version of the source code.
846 You can access versions of these documents specific to this release by going
847 into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
849 <p>If you have any questions or comments about LLVM, please feel free to contact
850 us via the <a href="http://llvm.org/docs/#maillist"> mailing
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