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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<link rel="stylesheet" href="llvm.css" type="text/css">
<title>LLVM 1.2 Release Notes</title>
</head>
<body>
<div class="doc_title">
LLVM 1.2 Release Notes
</div>
<ol>
<li><a href="#intro">Introduction</a></li>
<li><a href="#whatsnew">What's New?</a></li>
<li><a href="#portability">Portability and Supported Platforms</a></li>
<li><a href="#install-instructions">Installation Instructions</a></li>
<li><a href="#knownproblems">Known Problems</a>
<ul>
<li><a href="#core">Known problems with the LLVM Core</a>
<li><a href="#c-fe">Known problems with the C Front-end</a>
<li><a href="#c++-fe">Known problems with the C++ Front-end</a>
<li><a href="#x86-be">Known problems with the X86 Back-end</a>
<li><a href="#sparc-be">Known problems with the Sparc Back-end</a>
<li><a href="#c-be">Known problems with the C back-end</a>
</ul></li>
<li><a href="#additionalinfo">Additional Information</a></li>
</ol>
<div class="doc_text">
<p><b>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM team</a></b><p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="intro">Introduction</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This document contains the release notes for the LLVM compiler
infrastructure, release 1.2. Here we describe the status of LLVM, including any
known problems and bug fixes from the previous release. The most up-to-date
version of this document can be found on the <a
href="http://llvm.cs.uiuc.edu/releases/1.2/">LLVM 1.2 web site</a>. If you are
not reading this on the LLVM web pages, you should probably go there because
this document may be updated after the release.</p>
<p>For more information about LLVM, including information about potentially more
current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main
web site</a>. If you have questions or comments, the <a
href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
list</a> is a good place to send them.</p>
<p>Note that if you are reading this file from CVS, this document applies
to the <i>next</i> release, not the current one. To see the release notes for
the current or previous releases, see the <a
href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="whatsnew">What's New?</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This is the third public release of the LLVM compiler infrastructure.
</p>
<p>At this time, LLVM is known to correctly compile and run all non-unwinding C
& C++ SPEC CPU2000 benchmarks, the Olden benchmarks, and the Ptrdist
benchmarks. It has also been used to compile <b>many</b> other programs. LLVM
now also works with a broad variety of C++ programs, though it has still
received much less testing than the C front-end.
</p>
<p>
The LLVM native code generators are very stable but do not currently support
unwinding (exception throwing or <tt>longjmp</tt>ing), which prevent them from
working with programs like the <tt>253.perlbmk</tt> in SPEC CPU2000. The C
backend and the rest of LLVM supports these programs, so you can
still use LLVM with them. Support for unwinding will be added in a future
release.
</p>
<!--=========================================================================-->
<div class="doc_subsubsection">
This release implements the following new features:
</div>
<ol>
<li></li>
<li></li>
</ol>
<!--=========================================================================-->
<div class="doc_subsubsection">
In this release, the following missing features were implemented:
</div>
<ol>
<li></li>
<li></li>
</ol>
<!--=========================================================================-->
<div class="doc_subsubsection">
In this release, the following Quality of Implementation issues were fixed:
</div>
<ol>
<li><a href="http://llvm.cs.uiuc.edu/PR135">JIT should lazily initialize global variables</a></li>
<li><a href="http://llvm.cs.uiuc.edu/PR192">[X86] X86 Backend never releases memory for machine code structures</a></li>
<li></li>
</ol>
<!--=========================================================================-->
<div class="doc_subsubsection">
In this release, the following Code Quality issues were fixed:
</div>
<ol>
<li><a href="http://llvm.cs.uiuc.edu/PR187">[loopsimplify] Many pointless phi nodes are created</a></li>
<li></li>
</ol>
<!--=========================================================================-->
<div class="doc_subsubsection">
In this release, the following bugs in the previous release were fixed:
</div>
<p>Bugs in the LLVM Core:</p>
<ol>
<li><a href="http://llvm.cs.uiuc.edu/PR179">[licm] LICM promotes volatile memory
locations to registers</a></li>
<li><a href="http://llvm.cs.uiuc.edu/PR191">[licm] Memory read after free causes
infrequent crash</a></li>
<li><a href="http://llvm.cs.uiuc.edu/PR194">[indvars] Induction variable
canonicalization always makes 32-bit indvars</a></li>
</ol>
<p>Bugs in the C/C++ front-end:</p>
<ol>
<li><a href="http://llvm.cs.uiuc.edu/PR186">Need weak linkage on memory
management functions in libc runtime to allow them to be overriden</a></li>
<li></li>
</ol>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="portability">Portability and Supported Platforms</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>LLVM has been extensively tested on Intel and AMD machines running Red
Hat Linux and FreeBSD. It has also been tested on Sun UltraSPARC workstations running Solaris 8.
Additionally,
LLVM works on Mac OS X 10.3 and above, but only with the C backend or
interpreter (no native backend for the PowerPC is available yet).
The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
work on more platforms than that. However, it is likely that we
missed something and that minor porting is required to get LLVM to work on
new platforms. We welcome portability patches and error messages.</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="knownproblems">Known Problems</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This section contains all known problems with the LLVM system, listed by
component. As new problems are discovered, they will be added to these
sections. If you run into a problem, please check the <a
href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
there isn't already one.</p>
</div>
<!-- _______________________________________________________________________ -->
<!--
</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
-->
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="core">Known problems with the LLVM Core</a>
</div>
<div class="doc_text">
<ul>
<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not
work.</li>
<li>The JIT does not use mutexes to protect its internal data structures. As
such, execution of a threaded program could cause these data structures to be
corrupted.</li>
<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.</li>
<li>Linking in static archive files (.a files) is very slow (there is no symbol
table in the archive).</li>
<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
more than 256 elements</a>.</li>
<li>
The gccld program
<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=139">
does not link objects/archives in the order specified on the command line.
</a>
</li>
<li>
<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=174">
Tail duplication does not update SSA form correctly.
</a>
</li>
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="c-fe">Known problems with the C front-end</a>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">Bugs</div>
<div class="doc_text">
<ul>
<li>C99 Variable sized arrays do not release stack memory when they go out of
scope. Thus, the following program may run out of stack space:
<pre>
for (i = 0; i != 1000000; ++i) {
int X[n];
foo(X);
}
</pre></li>
<li>
Initialization of global union variables can only be done
<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=162">with the largest
union member</a>.
</li>
<li>
<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=182">
Functions marked "extern inline" are not compiled into LLVM with linkonce
linkage.
</a>
</li>
<li>
The memory management functions in the libc runtime
<a href="http://llvm.cs.uiuc.edu/PR186">need weak linkage so that they can be
overridden.
</a>
</li>
</ul>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
Notes
</div>
<div class="doc_text">
<ul>
<li>Inline assembly is not yet supported.</li>
<li>"long double" is transformed by the front-end into "double". There is no
support for floating point data types of any size other than 32 and 64
bits.</li>
<li>The following Unix system functionality has not been tested and may not
work:
<ol>
<li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
<tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
<li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
- These functions have not been tested.
</ol></li>
<li>Although many GCC extensions are supported, some are not. In particular,
the following extensions are known to <b>not be</b> supported:
<
|
