mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-27 13:29:50 +00:00
e0518449c7
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115297 91177308-0d34-0410-b5e6-96231b3b80d8
1035 lines
36 KiB
HTML
1035 lines
36 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
|
|
"http://www.w3.org/TR/html4/strict.dtd">
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<link rel="stylesheet" href="llvm.css" type="text/css">
|
|
<title>LLVM 2.8 Release Notes</title>
|
|
</head>
|
|
<body>
|
|
|
|
<div class="doc_title">LLVM 2.8 Release Notes</div>
|
|
|
|
<img align=right src="http://llvm.org/img/DragonSmall.png"
|
|
width="136" height="136" alt="LLVM Dragon Logo">
|
|
|
|
<ol>
|
|
<li><a href="#intro">Introduction</a></li>
|
|
<li><a href="#subproj">Sub-project Status Update</a></li>
|
|
<li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
|
|
<li><a href="#whatsnew">What's New in LLVM 2.8?</a></li>
|
|
<li><a href="GettingStarted.html">Installation Instructions</a></li>
|
|
<li><a href="#knownproblems">Known Problems</a></li>
|
|
<li><a href="#additionalinfo">Additional Information</a></li>
|
|
</ol>
|
|
|
|
<div class="doc_author">
|
|
<p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
|
|
</div>
|
|
|
|
<!--
|
|
<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
|
|
release.<br>
|
|
You may prefer the
|
|
<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
|
|
Release Notes</a>.</h1>
|
|
-->
|
|
|
|
<!-- *********************************************************************** -->
|
|
<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 2.8. Here we describe the status of LLVM, including
|
|
major improvements from the previous release and significant known problems.
|
|
All LLVM releases may be downloaded from the <a
|
|
href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
|
|
|
|
<p>For more information about LLVM, including information about the latest
|
|
release, please check out the <a href="http://llvm.org/">main LLVM
|
|
web site</a>. If you have questions or comments, the <a
|
|
href="http://lists.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 a Subversion checkout 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 a specific release, please see the
|
|
<a href="http://llvm.org/releases/">releases page</a>.</p>
|
|
|
|
</div>
|
|
|
|
|
|
<!--
|
|
Almost dead code.
|
|
include/llvm/Analysis/LiveValues.h => Dan
|
|
lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
|
|
llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
|
|
GEPSplitterPass
|
|
-->
|
|
|
|
|
|
<!-- Features that need text if they're finished for 2.9:
|
|
combiner-aa?
|
|
strong phi elim
|
|
loop dependence analysis
|
|
TBAA
|
|
CorrelatedValuePropagation
|
|
-->
|
|
|
|
<!-- Announcement, lldb, libc++ -->
|
|
|
|
<!-- to write:
|
|
MachineCSE tuned and on by default.
|
|
llvm.dbg.value: variable debug info for optimized code
|
|
MC Assembler backend is now real, does relaxation and is bitwise identical
|
|
with darwin assembler in huge majority of all cases.
|
|
new GHC calling convention
|
|
New half float intrinsics LangRef.html#int_fp16
|
|
Rewrote tblgen's type inference for backends to be more consistent and
|
|
diagnose more target bugs. This also allows limited support for writing
|
|
patterns for instructions that return multiple results, e.g. a virtual
|
|
register and a flag result. Stuff that used 'parallel' before should use
|
|
this.
|
|
New ARM/Thumb disassembler support in MC.
|
|
New SSEDomainFix pass:
|
|
On Nehalem and newer CPUs there is a 2 cycle latency penalty on using a
|
|
register in a different domain than where it was defined. Some instructions
|
|
have equvivalents for different domains, like por/orps/orpd. The
|
|
SSEDomainFix pass tries to minimize the number of domain crossings by
|
|
changing between equvivalent opcodes where possible.
|
|
Support for the Intel AES instructions in the assembler.
|
|
memcpy, memmove, and memset now take address space qualified pointers + volatile.
|
|
per-instruction debug info metadata is much faster and uses less space (new DebugLoc class).
|
|
-ffunction-sections and -fdata-sections are supported on ELF targets.
|
|
Now iterate function passes when a cgsccpassmanager detects a devirtualization
|
|
-momit-leaf-frame-pointer now supported.
|
|
New -regalloc=fast, =local got removed
|
|
New -regalloc=default option that chooses a register allocator based on the -O optimization level.
|
|
New "trap values" concept: http://llvm.org/docs/LangRef.html#trapvalues
|
|
Improved trip count analysis for <= and >= loops, and uses sign overflow info.
|
|
REMOVED: SCCVN pass.
|
|
X86 backend attempts to promote 16-bit integer operations to 32-bits to avoid
|
|
0x66 prefixes, which are slow on some microarchitectures and bloat the code
|
|
on others.
|
|
X87 fp stackifier is global!
|
|
LTO debug info support?
|
|
NEON: Better performance for QQQQ (4-consecutive Q register) instructions. New reg sequence abstraction?
|
|
New support for X86 "thiscall" calling convention (x86_thiscallcc in IR).
|
|
ARM: Better scheduling (list-hybrid, hybrid?)
|
|
New SubRegIndex tblgen class for targets -> jakob
|
|
ARM: Tail call support.
|
|
AVX support in the MC assembler. Full compiler support not done yet.
|
|
Atomics now get legalized when not natively supported (jim g)
|
|
ARM: General performance work and tuning.
|
|
-->
|
|
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="subproj">Sub-project Status Update</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
The LLVM 2.8 distribution currently consists of code from the core LLVM
|
|
repository (which roughly includes the LLVM optimizers, code generators
|
|
and supporting tools), the Clang repository and the llvm-gcc repository. In
|
|
addition to this code, the LLVM Project includes other sub-projects that are in
|
|
development. Here we include updates on these subprojects.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
|
|
C++, and Objective-C languages. Clang aims to provide a better user experience
|
|
through expressive diagnostics, a high level of conformance to language
|
|
standards, fast compilation, and low memory use. Like LLVM, Clang provides a
|
|
modular, library-based architecture that makes it suitable for creating or
|
|
integrating with other development tools. Clang is considered a
|
|
production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
|
|
(32- and 64-bit), and for darwin-arm targets.</p>
|
|
|
|
<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
|
|
|
|
<ul>
|
|
<li>Surely these guys have done something</li>
|
|
<li>X86-64 abi improvements? Did they make it in?</li>
|
|
</ul>
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="clangsa">Clang Static Analyzer</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
|
|
project is an effort to use static source code analysis techniques to
|
|
automatically find bugs in C and Objective-C programs (and hopefully <a
|
|
href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
|
|
future</a>!). The tool is very good at finding bugs that occur on specific
|
|
paths through code, such as on error conditions.</p>
|
|
|
|
<p>The LLVM 2.8 release fixes a number of bugs and slightly improves precision
|
|
over 2.7, but there are no major new features in the release.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
|
|
a JVM and a CLI Virtual Machine (Microsoft .NET is an
|
|
implementation of the CLI) using LLVM for static and just-in-time
|
|
compilation.</p>
|
|
|
|
<p>With the release of LLVM 2.8, ...</p>
|
|
|
|
</div>
|
|
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
|
|
is a simple library that provides an implementation of the low-level
|
|
target-specific hooks required by code generation and other runtime components.
|
|
For example, when compiling for a 32-bit target, converting a double to a 64-bit
|
|
unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
|
|
function. The compiler-rt library provides highly optimized implementations of
|
|
this and other low-level routines (some are 3x faster than the equivalent
|
|
libgcc routines).</p>
|
|
|
|
<p>
|
|
All of the code in the compiler-rt project is available under the standard LLVM
|
|
License, a "BSD-style" license. New in LLVM 2.8:
|
|
|
|
Soft float support
|
|
</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
|
|
gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
|
|
modifications whatsoever (currently one small patch is needed) thanks to the
|
|
new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
|
|
DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
|
|
generators instead of gcc's, just like with llvm-gcc.
|
|
</p>
|
|
|
|
<p>
|
|
DragonEgg is still a work in progress, but it is able to compile a lot of code,
|
|
for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
|
|
well, while all other languages either don't work at all or only work poorly.
|
|
For the moment only the x86-32 and x86-64 targets are supported, and only on
|
|
linux and darwin (darwin may need additional gcc patches).
|
|
</p>
|
|
|
|
<p>
|
|
The 2.8 release has the following notable changes:
|
|
<ul>
|
|
<li>The plugin loads faster due to exporting fewer symbols.</li>
|
|
<li>Additional vector operations such as addps256 are now supported.</li>
|
|
<li>Ada global variables with no initial value are no longer zero initialized,
|
|
resulting in better optimization.</li>
|
|
<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc
|
|
optimizers, rather than just a handful.</li>
|
|
<li>Fortran programs using common variables now link correctly.</li>
|
|
<li>GNU OMP constructs no longer crash the compiler.</li>
|
|
</ul>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="lldb">LLDB: Low Level Debugger</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://lldb.llvm.org/">LLDB</a> is</p>
|
|
|
|
<p>
|
|
</p>
|
|
|
|
<p>
|
|
2.8 status here.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="libc++">libc++: C++ Standard Library</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://libc++.llvm.org/">libc++</a> is</p>
|
|
|
|
<p>
|
|
</p>
|
|
|
|
<p>
|
|
2.8 status here.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>An exciting aspect of LLVM is that it is used as an enabling technology for
|
|
a lot of other language and tools projects. This section lists some of the
|
|
projects that have already been updated to work with LLVM 2.8.</p>
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="tce">TTA-based Codesign Environment (TCE)</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
|
|
application-specific processors (ASP) based on the Transport triggered
|
|
architecture (TTA). The toolset provides a complete co-design flow from C/C++
|
|
programs down to synthesizable VHDL and parallel program binaries. Processor
|
|
customization points include the register files, function units, supported
|
|
operations, and the interconnection network.</p>
|
|
|
|
<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
|
|
independent optimizations and also for parts of code generation. It generates
|
|
new LLVM-based code generators "on the fly" for the designed TTA processors and
|
|
loads them in to the compiler backend as runtime libraries to avoid per-target
|
|
recompilation of larger parts of the compiler chain.</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="Horizon">Horizon Bytecode Compiler</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode
|
|
language and compiler written on top of LLVM, intended for producing
|
|
single-address-space managed code operating systems that
|
|
run faster than the equivalent multiple-address-space C systems.
|
|
More in-depth blurb is available on <a
|
|
href="http://www.quokforge.org/projects/horizon/wiki/Wiki">the wiki</a>.</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="clamav">Clam AntiVirus</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href=http://www.clamav.net>Clam AntiVirus</a> is an open source (GPL)
|
|
anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
|
|
gateways. Since version 0.96 it has <a
|
|
href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
|
|
signatures</a> that allow writing detections for complex malware. It
|
|
uses LLVM's JIT to speed up the execution of bytecode on
|
|
X86,X86-64,PPC32/64, falling back to its own interpreter otherwise.
|
|
The git version was updated to work with LLVM 2.8
|
|
</p>
|
|
|
|
<p>The <a
|
|
href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf">
|
|
ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like
|
|
language, insert runtime checks, and generate ClamAV bytecode.</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="pure">Pure</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://pure-lang.googlecode.com/">Pure</a>
|
|
is an algebraic/functional
|
|
programming language based on term rewriting. Programs are collections
|
|
of equations which are used to evaluate expressions in a symbolic
|
|
fashion. Pure offers dynamic typing, eager and lazy evaluation, lexical
|
|
closures, a hygienic macro system (also based on term rewriting),
|
|
built-in list and matrix support (including list and matrix
|
|
comprehensions) and an easy-to-use C interface. The interpreter uses
|
|
LLVM as a backend to JIT-compile Pure programs to fast native code.</p>
|
|
|
|
<p>Pure versions 0.44 and later have been tested and are known to work with
|
|
LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="GHC">Glasgow Haskell Compiler (GHC)</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://www.haskell.org/ghc/">GHC</a> is an open source,
|
|
state-of-the-art programming suite for
|
|
Haskell, a standard lazy functional programming language. It includes
|
|
an optimizing static compiler generating good code for a variety of
|
|
platforms, together with an interactive system for convenient, quick
|
|
development.</p>
|
|
|
|
<p>In addition to the existing C and native code generators, GHC 7.0 now
|
|
supports an <a
|
|
href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM
|
|
code generator</a>. GHC supports LLVM 2.7 and later.</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="Clay">Clay Programming Language</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming
|
|
language that is specifically designed for generic programming. It makes
|
|
generic programming very concise thanks to whole program type propagation. It
|
|
uses LLVM as its backend.</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="llvm-py">llvm-py Python Bindings for LLVM</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work
|
|
with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a
|
|
compiler backend or a VM in Python.</p>
|
|
|
|
</div>
|
|
|
|
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="whatsnew">What's New in LLVM 2.8?</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>This release includes a huge number of bug fixes, performance tweaks and
|
|
minor improvements. Some of the major improvements and new features are listed
|
|
in this section.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="orgchanges">LLVM Community Changes</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>In addition to changes to the code, between LLVM 2.7 and 2.8, a number of
|
|
organization changes have happened:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>libc++ and lldb are new</li>
|
|
<li>Debugging optimized code support.</li>
|
|
</ul>
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="majorfeatures">Major New Features</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>LLVM 2.8 includes several major new capabilities:</p>
|
|
|
|
<ul>
|
|
<li>atomic lowering pass.</li>
|
|
<li>RegionInfo pass: opt -regions analyze" or "opt -view-regions".
|
|
<!-- Tobias Grosser --></li>
|
|
<li>ARMGlobalMerge: <!-- Anton --> </li>
|
|
<li>llvm-diff</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="coreimprovements">LLVM IR and Core Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>LLVM IR has several new features for better support of new targets and that
|
|
expose new optimization opportunities:</p>
|
|
|
|
<ul>
|
|
|
|
<li>LLVM 2.8 changes the internal order of operands in <a
|
|
href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
|
|
and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
|
|
To be portable across releases, resort to <tt>CallSite</tt> and the
|
|
high-level accessors, such as <tt>getCalledValue</tt> and <tt>setUnwindDest</tt>.
|
|
</li>
|
|
<li>
|
|
You can no longer pass use_iterators directly to cast<> (and similar), because
|
|
these routines tend to perform costly dereference operations more than once. You
|
|
have to dereference the iterators yourself and pass them in.
|
|
</li>
|
|
<li>
|
|
llvm.memcpy.*, llvm.memset.*, llvm.memmove.* (and possibly other?) intrinsics
|
|
take an extra parameter now (i1 isVolatile), totaling 5 parameters.
|
|
If you were creating these intrinsic calls and prototypes yourself (as opposed
|
|
to using Intrinsic::getDeclaration), you can use UpgradeIntrinsicFunction/UpgradeIntrinsicCall
|
|
to be portable accross releases.
|
|
Note that you cannot use Intrinsic::getDeclaration() in a backwards compatible
|
|
way (needs 2/3 types now, in 2.7 it needed just 1).
|
|
</li>
|
|
<li>
|
|
SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
|
|
Change your code to use
|
|
SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
|
|
</li>
|
|
<li>
|
|
VISIBILITY_HIDDEN is gone.
|
|
</li>
|
|
<li>
|
|
The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
|
|
considered deprecated, but continue to function in LLVM 2.8. Clients are
|
|
strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
|
|
<tt>INITIALIZE_AG_PASS()</tt> macros instead.
|
|
<li>
|
|
SMDiagnostic takes different parameters now. //FIXME: how to upgrade?
|
|
</li>
|
|
<li>
|
|
The constructor for the Triple class no longer tries to understand odd triple
|
|
specifications. Frontends should ensure that they only pass valid triples to
|
|
LLVM. The Triple::normalize utility method has been added to help front-ends
|
|
deal with funky triples.
|
|
<li>
|
|
Some APIs got renamed:
|
|
<ul>
|
|
<li>llvm_report_error -> report_fatal_error</li>
|
|
<li>llvm_install_error_handler -> install_fatal_error_handler</li>
|
|
<li>llvm::DwarfExceptionHandling -> llvm::JITExceptionHandling</li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="optimizer">Optimizer Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>In addition to a large array of minor performance tweaks and bug fixes, this
|
|
release includes a few major enhancements and additions to the optimizers:</p>
|
|
|
|
<ul>
|
|
|
|
<li></li>
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="executionengine">Interpreter and JIT Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li></li>
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="mc">MC Level Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>
|
|
FIXME: Rewrite.
|
|
|
|
The LLVM Machine Code (aka MC) sub-project of LLVM was created to solve a number
|
|
of problems in the realm of assembly, disassembly, object file format handling,
|
|
and a number of other related areas that CPU instruction-set level tools work
|
|
in. It is a sub-project of LLVM which provides it with a number of advantages
|
|
over other compilers that do not have tightly integrated assembly-level tools.
|
|
For a gentle introduction, please see the <a
|
|
href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
|
|
LLVM MC Project Blog Post</a>.
|
|
</p>
|
|
|
|
<p>2.8 status here. Basic correctness, some obscure missing instructions on
|
|
mainline, on by default in clang.
|
|
Entire compiler backend converted to use mcstreamer.
|
|
</p>
|
|
</div>
|
|
|
|
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="codegen">Target Independent Code Generator Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>We have put a significant amount of work into the code generator
|
|
infrastructure, which allows us to implement more aggressive algorithms and make
|
|
it run faster:</p>
|
|
|
|
<ul>
|
|
<li>MachO writer works.</li>
|
|
</ul>
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="x86">X86-32 and X86-64 Target Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>New features of the X86 target include:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>The X86 backend now supports holding X87 floating point stack values
|
|
in registers across basic blocks, dramatically improving performance of code
|
|
that uses long double, and when targetting CPUs that don't support SSE.</li>
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="ARM">ARM Target Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>New features of the ARM target include:
|
|
</p>
|
|
|
|
<ul>
|
|
|
|
<li>
|
|
All of the NEON load and store intrinsics (llvm.arm.neon.vld* and
|
|
llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes
|
|
of the memory being accessed.
|
|
</li>
|
|
<li>
|
|
The llvm.arm.neon.vaba intrinsic (vector absolute difference and
|
|
accumulate) has been removed. This operation is now represented using
|
|
the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a
|
|
vector add.
|
|
</li>
|
|
<li>
|
|
The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening
|
|
vector absolute difference with and without accumlation) have been removed.
|
|
They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute
|
|
difference) followed by a vector zero-extend operation, and for vabal,
|
|
a vector add.
|
|
</li>
|
|
<li>
|
|
The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic
|
|
are now replaced by vector truncate operations.
|
|
</li>
|
|
<li>
|
|
The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been
|
|
removed. They are now represented as vector sign-extend (vmovls) and
|
|
zero-extend (vmovlu) operations.
|
|
</li>
|
|
<li>
|
|
The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and
|
|
llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have
|
|
been removed. They are replaced by vector add and vector subtract operations
|
|
where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either
|
|
sign-extended or zero-extended.
|
|
</li>
|
|
<li>
|
|
The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and
|
|
llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without
|
|
accumulation and subtraction) have been removed. These operations are now
|
|
represented as vector multiplications where the operands are either
|
|
sign-extended or zero-extended, followed by a vector add for vmlal or a
|
|
vector subtract for vmlsl. Note that the polynomial vector multiply
|
|
intrinsic, llvm.arm.neon.vmullp, remains unchanged.
|
|
</li>
|
|
|
|
</ul>
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="newapis">New Useful APIs</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>This release includes a number of new APIs that are used internally, which
|
|
may also be useful for external clients.
|
|
</p>
|
|
|
|
<ul>
|
|
<li></li>
|
|
</ul>
|
|
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="otherimprovements">Other Improvements and New Features</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>Other miscellaneous features include:</p>
|
|
|
|
<ul>
|
|
<li></li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="changes">Major Changes and Removed Features</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>If you're already an LLVM user or developer with out-of-tree changes based
|
|
on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
|
|
from the previous release.</p>
|
|
|
|
<ul>
|
|
<li>.ll file doesn't produce #uses comments anymore, to get them, run a .bc file
|
|
through "llvm-dis --show-annotations".</li>
|
|
<li>MSIL Backend removed.</li>
|
|
<li>ABCD and SSI passes removed.</li>
|
|
<li>'Union' LLVM IR feature removed.</li>
|
|
</ul>
|
|
|
|
<p>In addition, many APIs have changed in this release. Some of the major LLVM
|
|
API changes are:</p>
|
|
|
|
<ul>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="knownproblems">Known Problems</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>This section contains significant known problems with the LLVM system,
|
|
listed by component. If you run into a problem, please check the <a
|
|
href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
|
|
there isn't already one.</p>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="experimental">Experimental features included with this release</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>The following components of this LLVM release are either untested, known to
|
|
be broken or unreliable, or are in early development. These components should
|
|
not be relied on, and bugs should not be filed against them, but they may be
|
|
useful to some people. In particular, if you would like to work on one of these
|
|
components, please contact us on the <a
|
|
href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
|
|
|
|
<ul>
|
|
<li>The Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
|
|
backends are experimental.</li>
|
|
<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
|
|
supported value for this option. XXX Update me</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="x86-be">Known problems with the X86 back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li>The X86 backend does not yet support
|
|
all <a href="http://llvm.org/PR879">inline assembly that uses the X86
|
|
floating point stack</a>. It supports the 'f' and 't' constraints, but not
|
|
'u'.</li>
|
|
<li>Win64 code generation wasn't widely tested. Everything should work, but we
|
|
expect small issues to happen. Also, llvm-gcc cannot build the mingw64
|
|
runtime currently due to lack of support for the 'u' inline assembly
|
|
constraint and for X87 floating point inline assembly.</li>
|
|
<li>The X86-64 backend does not yet support the LLVM IR instruction
|
|
<tt>va_arg</tt>. Currently, front-ends support variadic
|
|
argument constructs on X86-64 by lowering them manually.</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>The Linux PPC32/ABI support needs testing for the interpreter and static
|
|
compilation, and lacks support for debug information.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="arm-be">Known problems with the ARM back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
|
|
processors, thumb programs can crash or produce wrong
|
|
results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
|
|
<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
|
|
</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="sparc-be">Known problems with the SPARC back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
|
|
support the 64-bit SPARC ABI (-m64).</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="mips-be">Known problems with the MIPS back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li>64-bit MIPS targets are not supported yet.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="alpha-be">Known problems with the Alpha back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
|
|
<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
|
|
appropriate nops inserted to ensure restartability.</li>
|
|
|
|
</ul>
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="c-be">Known problems with the C back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>The C backend has numerous problems and is not being actively maintained.
|
|
Depending on it for anything serious is not advised.</p>
|
|
|
|
<ul>
|
|
<li><a href="http://llvm.org/PR802">The C backend has only basic support for
|
|
inline assembly code</a>.</li>
|
|
<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
|
|
C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
|
|
C++ code compiled with <tt>llc</tt> or native compilers.</li>
|
|
<li>The C backend does not support all exception handling constructs.</li>
|
|
<li>The C backend does not support arbitrary precision integers.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>llvm-gcc is generally very stable for the C family of languages. The only
|
|
major language feature of GCC not supported by llvm-gcc is the
|
|
<tt>__builtin_apply</tt> family of builtins. However, some extensions
|
|
are only supported on some targets. For example, trampolines are only
|
|
supported on some targets (these are used when you take the address of a
|
|
nested function).</p>
|
|
|
|
<p>Fortran support generally works, but there are still several unresolved bugs
|
|
in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
|
|
tools/gfortran component for details. Note that llvm-gcc is missing major
|
|
Fortran performance work in the frontend and library that went into GCC after
|
|
4.2. If you are interested in Fortran, we recommend that you consider using
|
|
<a href="#dragonegg">dragonegg</a> instead.</p>
|
|
|
|
<p>The llvm-gcc 4.2 Ada compiler has basic functionality. However, this is not a
|
|
mature technology, and problems should be expected. For example:</p>
|
|
<ul>
|
|
<li>The Ada front-end currently only builds on X86-32. This is mainly due
|
|
to lack of trampoline support (pointers to nested functions) on other platforms.
|
|
However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
|
|
which does support trampolines.</li>
|
|
<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
|
|
This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
|
|
exception handling, which is used internally by the compiler.
|
|
Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
|
|
<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
|
|
and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
|
|
(c380004 also fails with gcc-4.2 mainline).
|
|
If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
|
|
causes the compiler to go into an infinite loop, using up all system memory.</li>
|
|
<li>Some GCC specific Ada tests continue to crash the compiler.</li>
|
|
<li>The <tt>-E</tt> binder option (exception backtraces)
|
|
<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
|
|
crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
|
|
<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
|
|
or finish at a non-byte offset</a> in a record. Workaround: do not pack records
|
|
or use representation clauses that result in a field of a non-discrete type
|
|
starting or finishing in the middle of a byte.</li>
|
|
<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
|
|
'main' as generated by the Ada binder to be invalid</a>.
|
|
Workaround: hand edit the file to use pointers for <tt>argv</tt> and
|
|
<tt>envp</tt> rather than integers.</li>
|
|
<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
|
|
ignored</a>.</li>
|
|
</ul>
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="additionalinfo">Additional Information</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>A wide variety of additional information is available on the <a
|
|
href="http://llvm.org">LLVM web page</a>, in particular in the <a
|
|
href="http://llvm.org/docs/">documentation</a> section. The web page also
|
|
contains versions of the API documentation which is up-to-date with the
|
|
Subversion 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://llvm.org/docs/#maillist"> mailing
|
|
lists</a>.</p>
|
|
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
|
|
<hr>
|
|
<address>
|
|
<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
|
|
src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
|
|
<a href="http://validator.w3.org/check/referer"><img
|
|
src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
|
|
|
|
<a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
|
|
Last modified: $Date$
|
|
</address>
|
|
|
|
</body>
|
|
</html>
|