<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 1.4 Release Notes</title>
+ <title>LLVM 1.6 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 1.4 Release Notes</div>
+<div class="doc_title">LLVM 1.6 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</a></li>
<li><a href="GettingStarted.html">Installation Instructions</a></li>
<li><a href="#portability">Portability and Supported Platforms</a></li>
<li><a href="#knownproblems">Known Problems</a>
- <ul>
- <li><a href="#experimental">Experimental features included in this
- release</a>
- <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="#sparcv9-be">Known problems with the SparcV9 Back-end</a>
- <li><a href="#ppc-be">Known problems with the PowerPC 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_author">
- <p>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM team</a><p>
+ <p>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM Team</a><p>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This document contains the release notes for the LLVM compiler
-infrastructure, release 1.4. Here we describe the status of LLVM, including any
-known problems and improvements 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/1.4/">LLVM 1.4 web site</a>. If you are
+infrastructure, release 1.6. Here we describe the status of LLVM, including any
+known problems and major improvements 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/1.6/">LLVM 1.6 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>
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
+<p>Note that if you are reading this file from CVS or the main LLVM web page,
+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_text">
-<p>This is the fifth public release of the LLVM compiler infrastructure.</p>
+<p>This is the seventh public release of the LLVM Compiler Infrastructure.</p>
-<p> At this time, LLVM is known to correctly compile on a broad range of
-C and C++ programs, including the SPEC CPU95 & 2000 suite. This release
-includes several major enhancements to the LLVM system, including a new
-PowerPC JIT, enhancements to the C/C++ front-end to provide source line number
-information in LLVM, a new <a href="CommandGuide/html/llvmc.html">compiler
-driver</a>, and several other enhancements listed below. It also includes
-bug fixes for those problems found since the 1.3 release.</p>
-
-<p>Note that this release seperates the LLVM Program Testsuite out of the
-main LLVM distribution into a seperate CVS repository and tarball. This
-reduces the size of the main LLVM distribution. Also note that LLVM now
-builds tools into llvm/Debug/bin by default instead of llvm/tools/Debug.</p>
+<p>LLVM 1.6 is known to correctly compile a wide range of C and C++ programs,
+includes bug fixes for those problems found since the 1.5 release, and includes
+a large number of new features and enhancements, described below.</p>
</div>
<!--=========================================================================-->
-<div class="doc_subsubsection">
-<a name="newfeatures">This release implements the following new features:</a>
-</div>
-
-<div class="doc_text">
-<ol>
- <li>LLVM now includes a Just-In-Time compiler for the PowerPC target.</li>
- <li>llvmgcc and llvmg++ now emit source line number information when '-g' is
- passed in, making it possible to map from LLVM code back to source.
- This information is currently used by llvm-db and can be used with other
- tools and passes.</li>
- <li>The test/Programs hierarchy <a href="http://llvm.cs.uiuc.edu/PR257">has
- been moved out of the main LLVM tree</a> into a separate CVS repository and
- tarball. This shrinks the distribution size of LLVM itself significantly.
- </li>
- <li>LLVM now optimizes global variables more aggressively than it did
- before.</li>
- <li>LLVM now includes the new '<tt>undef</tt>' value and
- <a href="LangRef.html#i_unreachable"><tt>unreachable</tt></a> instruction,
- which give the optimizer more information about the behavior of the
- program.
- </li>
- <li>Bytecode compression with bzip2 has been implemented. All bytecode files
- generated by LLVM will now be compressed by default. Compression can be
- disabled with the <tt>-disable-compression</tt> option to the tools that can
- generate bytecode files.
- </li>
- <li>A generic <a href="CommandGuide/html/llvmc.html">compiler driver</a>
- (llvmc) and
- an associated <a href="CommandGuide/html/llvm-ld.html">generic linker</a>
- (llvm-ld) have been added. The compiler driver is generic because it can be
- configured
- to pre-process, translate, optimize, assemble, and link code from any source
- language with an LLVM front-end. This makes it easier for compiler writers
- to hide the multiple steps required to compile a program (compiling,
- optimizing, linking runtime libraries, etc) in one simple command.
- </li>
- <li>The <a href="http://llvm.cs.uiuc.edu/PR263">dependent libraries</a>
- feature has been implemented. This allows front end compilers to indicate in
- the bytecode which libraries the bytecode needs to be linked with. Both the
- C/C++ and Stacker front ends support generating the required dependencies.
- The linker now supports using this information to ensure required libaries are
- linked into the module. This minimizes the need to use the <tt>-l</tt> option
- when using <a href="CommandGuide/html/llvmc.html"><tt>llvmc</tt></a>.
- </li>
- <li>The LLVM makefiles have been improved to build LLVM much faster and
- includes new targets (like dist-check, uninstall). One important user-visible
- change is that libraries and tools will now be built into
- <tt>$builddir/Debug/{bin,lib}</tt>
- instead of <tt>$builddir/tools/Debug</tt> and <tt>$builddir/lib/Debug</tt>
- (Similarly for <tt>Release</tt> and <tt>Profile</tt> builds).
- </li>
- <li>The LLVM source code is much more compatible with Microsoft Visual C++,
- including the JIT and runtime-code generation, though the entire system
- may not work with it.
- </li>
- <li>The JIT-Target interfaces <a href="http://llvm.cs.uiuc.edu/PR283">are
- now much simpler</a> and more powerful.
- </li>
- <li>LLVM now provides llvm-ar and llvm-ranlib tools for working with archives
- of LLVM bytecode files.</li>
- <li>zlib and libpng are <a href="http://llvm.cs.uiuc.edu/PR417">no longer
- included in the main LLVM tarball</a>.</li>
- <li>The LLVM code generator now automatically generates assembly code writers
- from an abstract target descriptions, eliminating the need to write
- assembly printers manually.</li>
- <li>LLVM regression and feature tests now use DejaGNU instead of QMTest.</li>
-</ol>
-
-</div>
-
-
-<!--=========================================================================-->
-<div class="doc_subsubsection">
-In this release, the following missing features were implemented:
+<div class="doc_subsection">
+<a name="newfeatures">New Features in LLVM 1.6</a>
</div>
<div class="doc_text">
-
+<h1>
+ See <a href="/releases/1.5/docs/ReleaseNotes.html">LLVM 1.5 Release Notes</a>
+</h1>
<ol>
- <li><a href="http://llvm.cs.uiuc.edu/PR419">JIT interface should support
- arbitrary calls</a>
- </li>
- <li>The <tt>llvm-ar</tt> tool was previously incomplete and didn't properly
- support other ar(1) implementations. This has been corrected. <tt>llvm-ar</tt>
- now fully supports all archive editing functions, table of contents listing,
- extraction, and printing. It can also read BSD4.4/MacOSX and SVR4 style
- archives. See <a href="CommandGuide/html/llvm-ar.html">llvm-ar</a> for
- details.
+ <li>The JIT now uses mutexes to protect its internal data structures. This
+ allows multi-threaded programs to be run from the JIT or interpreter without
+ corruption of the internal data structures. See
+ <a href="http://llvm.cs.uiuc.edu/PR418">PR418</a> and
+ <a href="http://llvm.cs.uiuc.edu/PR540">PR540</a> for the details.
</li>
</ol>
-
</div>
<!--=========================================================================-->
-<div class="doc_subsubsection">
-<a name="qualityofimp">In this release, the following Quality of Implementation
-issues were fixed:</a>
-</div>
-
-<div class="doc_text">
-
-<ol>
- <li>The linker no longer <a href="http://llvm.cs.uiuc.edu/PR426">emits many
- useless warnings</a> when linking C++ programs.
- </li>
- <li>The LLVM <a href="http://llvm.cs.uiuc.edu/PR352">#include namespace</a>
- has been made consistent. Files in <tt>llvm/include/{Support,Config}</tt>
- are now located in <tt>llvm/include/llvm/{Support,Config}</tt>.
- </li>
- <li>The names of the libraries generated by compiling LLVM source have been
- changed to ensure they do not conflict with other packages upon installation.
- Each LLVM library is now prefixed with LLVM and uses mixed clase. For example,
- the library <tt>libasmparser.a</tt> in 1.3 has become
- <tt>libLLVMAsmParser.a</tt> in release 1.4.
- </li>
- <li>The C++ frontend no longer expands and emits <a
- href="http://llvm.cs.uiuc.edu/PR459">all inline functions, even if they
- are unused</a>. It now properly tracks which functions are needed and
- only compiles those.</li>
-
- <li>Many improvements in the <a href="http://llvm.cs.uiuc.edu/PR256">autoconf
- and makefile systems</a> have been implemented.</li>
-</ol>
+<div class="doc_subsection">
+<a name="codequality">Code Quality Improvements in LLVM 1.6</a>
</div>
<!--=========================================================================-->
-<div class="doc_subsubsection">
-<a name="codequality">This release includes the following Code Quality
-improvements:</a>
-</div>
-
-<div class="doc_text">
-<ol>
- <li>The optimizer produces <a href="http://llvm.cs.uiuc.edu/PR362">more
- efficient code for std::min/std::max</a> and other similar functions.</li>
- <li>The X86 backend generates substantially faster code for floating point
- intensive programs.</li>
- <li>The PowerPC backend generates more efficient code in many common
- scenarios.</li>
-</ol>
+<div class="doc_subsection">
+<a name="codequality">Code Generator Improvements in LLVM 1.6</a>
</div>
<!--=========================================================================-->
-<div class="doc_subsubsection">
-<a name="bugfix">In this release, the following bugs in the previous release
-were fixed:</a>
+<div class="doc_subsection">
+<a name="bugfix">Significant Bugs Fixed in LLVM 1.6</a>
</div>
<div class="doc_text">
-
-<p>Bugs fixed in the LLVM Core:</p>
-
-<ol>
- <li><a href="http://llvm.cs.uiuc.edu/PR420">[licm] LICM invalidates alias
- analysis info and uses broken information</a> (optimizer crash)</li>
- <li><a href="http://llvm.cs.uiuc.edu/PR422">[asmwriter] Asmwriter is really
- slow for functions with lots of values</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR423">[anders-aa] Andersen's AA is
- completely broken in LLVM 1.3</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR430">[bcwriter] Empty compaction
- tables defined</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR227">[X86] llc output for functions
- w/certain names tickles GNU 'as' bugs</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR472">[cbackend] Static globals are
- prototyped as 'extern'</a></li>
-</ol>
-
-<p>Bugs in the C/C++ front-end:</p>
-
<ol>
- <li><a href="http://llvm.cs.uiuc.edu/PR445">[llvmg++] not enough templates are
- instantiated</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR450">[llvmg++] Extern const globals
- cannot be marked 'constant' if they have nontrivial ctors or dtors</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR461">[llvmgcc] Crash compiling unnamed
- bitfield which does not increase struct size</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR424">[llvmgcc] llvmgcc emits invalid
- constant exprs</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR421">[llvmg++] Crash initializing
- array with constructors in hard EH situations</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR397">[llvm-gcc] Inline function
- redefinitions error due to 'asm' function rename</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR244">[llvm-gcc] Error when an
- implicitly external function is re-declared as static</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR360">[llvmgcc] Structure field with
- non-constant offset crashes llvmgcc</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR447">[llvmg++] Crash compiling
- friend with default argument</a></li>
+ <li><a href="http://llvm.cs.uiuc.edu/PR591">[simplify-libcalls] The simplify-libcalls pass generates ill-formed LLVM code</a>.</li>
</ol>
-
-<p>Bugs fixed in the Sparc V9 back-end:</p>
-
-<ol>
- <li><a href="http://llvm.cs.uiuc.edu/PR428">[sparcv9] regalloc assertion
- failure with certain indirect calls</a></li>
-</ol>
-
</div>
<!-- *********************************************************************** -->
<p>LLVM is known to work on the following platforms:</p>
<ul>
-<li>Intel and AMD machines running Red Hat Linux and FreeBSD (and probably
- other unix-like systems).</li>
+ <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
+ (and probably other unix-like systems).</li>
<li>Sun UltraSPARC workstations running Solaris 8.</li>
<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
support is available for native builds with Visual C++).</li>
<li>PowerPC-based Mac OS X systems, running 10.2 and above.</li>
+<li>Alpha-based machines running Debian GNU/Linux.</li>
+<li>Itanium-based machines running Linux and HP-UX.</li>
</ul>
<p>The core LLVM infrastructure uses
porting may be required to get LLVM to work on new platforms. We welcome your
portability patches and reports of successful builds or error messages.</p>
-<!--
-<p>Note that the LLVM build system does not currently support directories with
-spaces on them when running on Win32/cygwin. We strongly recommend running
-LLVM and the C frontend out of a top-level directory without spaces (e.g.,
-<tt>/cygdrive/c/llvm</tt>). Also, make sure to install <b>all</b> of the
-cygwin packages. By default, many important tools are not installed that
-are needed by the LLVM build process or test suite (e.g., /bin/time). Finally,
-please make sure that there are no directories with spaces in them in your
-PATH environment variable.</p>
--->
-
</div>
<!-- *********************************************************************** -->
<ul>
<li>The following passes are incomplete or buggy, and may be removed in future
- releases: <tt>-pgmdep, -memdep, -ipmodref, -cee, -branch-combine,
- -instloops, -paths, -pre</tt></li>
+ releases: <tt>-cee, -branch-combine, -instloops, -paths, -pre</tt></li>
<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
be used to step through programs and inspect the stack.</li>
-<li>The "iterative scan" register allocator (enabled with -regalloc=iterativescan)
- is not stable.</li>
+<li>The "iterative scan" register allocator (enabled with
+ <tt>-regalloc=iterativescan</tt>) is not stable.</li>
+<li>The SparcV8, Alpha, and IA64 code generators are experimental.</li>
</ul>
</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>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
+ work.</li>
<li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not
mark values live across a setjmp as volatile</a>. This missing feature
only affects targets whose setjmp/longjmp libraries do not save and restore
<tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
<tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
(currently ignored). We also support builtins for ISO C99 floating
- point comparison macros (e.g., <tt>__builtin_islessequal</tt>).</li>
+ point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
+ <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
+ <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
</ol>
<p>The following extensions <b>are</b> known to be supported:</p>
<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
front-end</a>.</li>
-<li><b>IA-64 specific</b>: The C++ front-end does not use <a
-href="http://llvm.cs.uiuc.edu/PR406">IA64 ABI compliant layout of v-tables</a>.
-In particular, it just stores function pointers instead of function
-descriptors in the vtable. This bug prevents mixing C++ code compiled with
-LLVM with C++ objects compiled by other C++ compilers.</li>
-
</ul>
</div>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="c-be">Known problems with the C back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+
+<li>The C back-end produces code that violates the ANSI C Type-Based Alias
+Analysis rules. As such, special options may be necessary to compile the code
+(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
+problem probably cannot be fixed.</li>
+
+<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
+supported</a>. This should not affect LLVM produced by the C or C++
+frontends.</li>
+
+</ul>
+
+</div>
+
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="x86-be">Known problems with the X86 back-end</a>
<div class="doc_text">
<ul>
- <li>none yet</li>
+<li><a href="http://llvm.cs.uiuc.edu/PR566">Memory Mapped I/O Intrinsics do not fence memory</a></li>
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="ppc-be">Known problems with the PowerPC back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+<li>None yet</li>
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="ppc-be">Known problems with the PowerPC back-end</a>
+ <a name="alpha-be">Known problems with the Alpha back-end</a>
</div>
<div class="doc_text">
<ul>
-<li>none yet</li>
+
+<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
+appropriate nops inserted to ensure restartability.</li>
+
+<li>Defining vararg functions is not supported (but calling them is ok).</li>
+
+<li>Due to the vararg problems, C++ exceptions do not work. Small changes are required to the CFE (which break correctness in the exception handler) to compile the exception handling library (and thus the C++ standard library).</li>
+
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="c-be">Known problems with the C back-end</a>
+ <a name="ia64-be">Known problems with the IA64 back-end</a>
</div>
<div class="doc_text">
<ul>
-<li>The C back-end produces code that violates the ANSI C Type-Based Alias
-Analysis rules. As such, special options may be necessary to compile the code
-(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
-problem probably cannot be fixed.</li>
+<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
+made where the argument is not 16-byte aligned, as required on IA64. (Strictly
+speaking this is not a bug in the IA64 back-end; it will also be encountered
+when building C++ programs using the C back-end.)</li>
-<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
-supported</a>. This should not affect LLVM produced by the C or C++
-frontends.</li>
+<li>The C++ front-end does not use <a href="http://llvm.cs.uiuc.edu/PR406">IA64
+ABI compliant layout of v-tables</a>. In particular, it just stores function
+pointers instead of function descriptors in the vtable. This bug prevents
+mixing C++ code compiled with LLVM with C++ objects compiled by other C++
+compilers.</li>
+
+<li>There are a few ABI violations which will lead to problems when mixing LLVM
+output with code built with other compilers, particularly for floating-point
+programs.</li>
+
+<li>Defining vararg functions is not supported (but calling them is ok).</li>
+
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="sparcv8">Known problems with the SPARC-V8 back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+<li>Many features are still missing (e.g. support for 64-bit integer
+arithmetic).</li>
+<li>This backend needs to be updated to use the SelectionDAG instruction
+selection framework.</li>
</ul>
</div>
<div class="doc_text">
-<p>A wide variety of additional information is available on the LLVM web page,
-including mailing lists and publications describing algorithms and components
-implemented in LLVM. The web page also contains versions of the API
-documentation which is up-to-date with the CVS version of the source code. You
-can access versions of these documents specific to this release by going into
-the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
+<p>A wide variety of additional information is available on the <a
+href="http://llvm.cs.uiuc.edu">LLVM web page</a>, including <a
+href="http://llvm.cs.uiuc.edu/docs/">documentation</a> and <a
+href="http://llvm.cs.uiuc.edu/pubs/">publications describing algorithms and
+components implemented in LLVM</a>. The web page also contains versions of the
+API documentation which is up-to-date with the CVS version of the source code.
+You can access versions of these documents specific to this release by going
+into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
<p>If you have any questions or comments about LLVM, please feel free to contact
-us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
+us via the <a href="http://llvm.cs.uiuc.edu/docs/#maillist"> mailing
lists</a>.</p>
</div>