diff options
author | Chris Lattner <sabre@nondot.org> | 2010-07-21 15:57:40 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2010-07-21 15:57:40 +0000 |
commit | 922d00f5f5fd202feecefadd223b12001931260b (patch) | |
tree | 6ac12ce3dd5f313cac51f3b48a8d1208e6a9aac4 /docs/ReleaseNotes.html | |
parent | bc565014357a89c91a46a647714cb0d256186cc9 (diff) | |
download | external_llvm-922d00f5f5fd202feecefadd223b12001931260b.zip external_llvm-922d00f5f5fd202feecefadd223b12001931260b.tar.gz external_llvm-922d00f5f5fd202feecefadd223b12001931260b.tar.bz2 |
strip out the 2.7 release notes, this really is the 2.8 release notes
now. Add a few items like the fpstackifier improvements.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109013 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs/ReleaseNotes.html')
-rw-r--r-- | docs/ReleaseNotes.html | 534 |
1 files changed, 27 insertions, 507 deletions
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index 38da71c..61aca32 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -118,40 +118,9 @@ 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 and Objective-C on x86 (32- and 64-bit).</p> -<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p> +<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p> <ul> - -<li>C++ Support: Clang is now capable of self-hosting! While still -alpha-quality, Clang's C++ support has matured enough to build LLVM and Clang, -and C++ is now enabled by default. See the <a -href="http://clang.llvm.org/cxx_compatibility.html">Clang C++ compatibility -page</a> for common C++ migration issues.</li> - -<li>Objective-C: Clang now includes experimental support for an updated -Objective-C ABI on non-Darwin platforms. This includes support for non-fragile -instance variables and accelerated proxies, as well as greater potential for -future optimisations. The new ABI is used when compiling with the --fobjc-nonfragile-abi and -fgnu-runtime options. Code compiled with these -options may be mixed with code compiled with GCC or clang using the old GNU ABI, -but requires the libobjc2 runtime from the GNUstep project.</li> - -<li>New warnings: Clang contains a number of new warnings, including -control-flow warnings (unreachable code, missing return statements in a -non-<code>void</code> function, etc.), sign-comparison warnings, and improved -format-string warnings.</li> - -<li>CIndex API and Python bindings: Clang now includes a C API as part of the -CIndex library. Although we may make some changes to the API in the future, it -is intended to be stable and has been designed for use by external projects. See -the Clang -doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a> -documentation for more details. The CIndex API also includes a preliminary -set of Python bindings.</li> - -<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM -ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now -suitable for use as a beta quality ARM compiler.</li> </ul> </div> @@ -170,10 +139,7 @@ suitable for use as a beta quality ARM compiler.</li> future</a>!). The tool is very good at finding bugs that occur on specific paths through code, such as on error conditions.</p> -<p>In the LLVM 2.7 time-frame, the analyzer core has made several major and - minor improvements, including better support for tracking the fields of - structures, initial support (not enabled by default yet) for doing - interprocedural (cross-function) analysis, and new checks have been added. +<p>In the LLVM 2.8 time-frame, </p> </div> @@ -190,26 +156,8 @@ 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 2.7, VMKit has shifted to a great framework for writing -virtual machines. VMKit now offers precise and efficient garbage collection with -multi-threading support, thanks to the MMTk memory management toolkit, as well -as just in time and ahead of time compilation with LLVM. The major changes in -VMKit 0.27 are:</p> - -<ul> - -<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors. - The first collector to be ported is the MarkSweep collector, which is precise, - and drastically improves the performance of VMKit.</li> -<li>Line number information in the JVM: by using the debug metadata of LLVM, the - JVM now supports precise line number information, useful when printing a stack - trace.</li> -<li>Interface calls in the JVM: we implemented a variant of the Interface Method - Table technique for interface calls in the JVM. -</li> +<p>With the release of LLVM 2.8, ...</p> -</ul> </div> @@ -231,8 +179,10 @@ 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 2.7: compiler_rt now -supports ARM targets.</p> +License, a "BSD-style" license. New in LLVM 2.8: + +Soft float support +</p> </div> @@ -265,7 +215,7 @@ supported, and only on linux and darwin (darwin needs an additional gcc patch). </p> <p> -DragonEgg is a new project which is seeing its first release with llvm-2.7. +2.8 status here. </p> </div> @@ -288,23 +238,13 @@ href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the LLVM MC Project Blog Post</a>. </p> -<p>2.7 includes major parts of the work required by the new MC Project. A few - targets have been refactored to support it, and work is underway to support a - native assembler in LLVM. This work is not complete in LLVM 2.7, but it has - made substantially more progress on LLVM mainline.</p> - -<p>One minor example of what MC can do is to transcode an AT&T syntax - X86 .s file into intel syntax. You can do this with something like:</p> -<pre> - llvm-mc foo.s -output-asm-variant=1 -o foo-intel.s -</pre> - +<p>2.8 status here</p> </div> <!-- *********************************************************************** --> <div class="doc_section"> - <a name="externalproj">External Open Source Projects Using LLVM 2.7</a> + <a name="externalproj">External Open Source Projects Using LLVM 2.8</a> </div> <!-- *********************************************************************** --> @@ -312,171 +252,13 @@ LLVM MC Project Blog Post</a>. <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 2.7.</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 0.43 and later have been tested and are known to work with -LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="RoadsendPHP">Roadsend PHP</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open -source implementation of the PHP programming -language that uses LLVM for its optimizer, JIT and static compiler. This is a -reimplementation of an earlier project that is now based on LLVM. -</p> -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="UnladenSwallow">Unladen Swallow</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a -branch of <a href="http://python.org/">Python</a> intended to be fully -compatible and significantly faster. It uses LLVM's optimization passes and JIT -compiler. -</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="safecode">SAFECode Compiler</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C -compiler built using LLVM. It takes standard, unannotated C code, analyzes the -code to ensure that memory accesses and array indexing operations are safe, and -instruments the code with run-time checks when safety cannot be proven -statically. -</p> -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="icedtea">IcedTea Java Virtual Machine Implementation</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a -harness to build OpenJDK using only free software build tools and to provide -replacements for the not-yet free parts of OpenJDK. One of the extensions that -IcedTea provides is a new JIT compiler named <a -href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM -to provide native code generation without introducing processor-dependent -code. -</p> -<p>Icedtea6 1.8 and later have been tested and are known to work with -LLVM 2.7 (and continue to work with older LLVM releases >= 2.6 as well). -</p> -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="llvm-lua">LLVM-Lua</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM - to add JIT and static compiling support to the Lua VM. Lua -bytecode is analyzed to remove type checks, then LLVM is used to compile the -bytecode down to machine code. -</p> -<p>LLVM-Lua 1.2.0 have been tested and is known to work with LLVM 2.7. -</p> -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="MacRuby">MacRuby</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby based on -core Mac OS technologies, sponsored by Apple Inc. It uses LLVM at runtime for -optimization passes, JIT compilation and exception handling. It also allows -static (ahead-of-time) compilation of Ruby code straight to machine code. -</p> -<p>The upcoming MacRuby 0.6 release works with LLVM 2.7. -</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 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.</p> - + projects that have already been updated to work with LLVM 2.8.</p> </div> <!-- *********************************************************************** --> <div class="doc_section"> - <a name="whatsnew">What's New in LLVM 2.7?</a> + <a name="whatsnew">What's New in LLVM 2.8?</a> </div> <!-- *********************************************************************** --> @@ -496,29 +278,11 @@ in this section. <div class="doc_text"> -<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of +<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>LLVM has a new <a href="http://llvm.org/Logo.html">official logo</a>!</li> - -<li>Ted Kremenek and Doug Gregor have stepped forward as <a - href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the - Clang static analyzer and the Clang frontend, respectively.</li> - -<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at - <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way - to learn about new LLVM-related features as they are implemented. Several - features in this release are already explained on the blog.</li> - -<li>The LLVM web pages are now checked into the SVN server, in the "www", - "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a - largely inaccessible old CVS server.</li> - -<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much - faster) server. It is still graciously hosted at the University of Illinois - of Urbana Champaign.</li> </ul> </div> @@ -529,43 +293,10 @@ organization changes have happened: <div class="doc_text"> -<p>LLVM 2.7 includes several major new capabilities:</p> +<p>LLVM 2.8 includes several major new capabilities:</p> <ul> -<li>2.7 includes initial support for the <a - href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target. - MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li> - -<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature - supports many different use cases, including allowing front-end authors to - encode source level information into LLVM IR, which is consumed by later - language-specific passes. This is a great way to do high-level optimizations - like devirtualization, type-based alias analysis, etc. See the <a - href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html"> - Extensible Metadata Blog Post</a> for more information.</li> - -<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a> -in a completely new way, built on extensible metadata. The new implementation -is much more memory efficient and paves the way for improvements to optimized -code debugging experience.</li> - -<li>2.7 now directly supports taking the address of a label and doing an - indirect branch through a pointer. This is particularly useful for - interpreter loops, and is used to implement the GCC "address of label" - extension. For more information, see the <a -href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html"> -Address of Label and Indirect Branches in LLVM IR Blog Post</a>. - -<li>2.7 is the first release to start supporting APIs for assembling and - disassembling target machine code. These APIs are useful for a variety of - low level clients, and are surfaced in the new "enhanced disassembly" API. - For more information see the <a - href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86 - Disassembler Blog Post</a> for more information.</li> - -<li>2.7 includes major parts of the work required by the new MC Project, - see the <a href="#mc">MC update above</a> for more information.</li> - +<li>.</li> </ul> </div> @@ -580,31 +311,6 @@ Address of Label and Indirect Branches in LLVM IR Blog Post</a>. expose new optimization opportunities:</p> <ul> -<li>LLVM IR now supports a 16-bit "half float" data type through <a - href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li> -<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function - attributes</a>: inlinehint and alignstack(n). The former is a hint to the - optimizer that a function was declared 'inline' and thus the inliner should - weight it higher when considering inlining it. The later - indicates to the code generator that the function diverges from the platform - ABI on stack alignment.</li> -<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic - allows the optimizer to infer the sizes of memory objects in some cases. - This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt> - extension.</li> -<li>LLVM IR now supports marking load and store instructions with <a - href="LangRef.html#i_load">"non-temporal" hints</a> (building on the new - metadata feature). This hint encourages the code - generator to generate non-temporal accesses when possible, which are useful - for code that is carefully managing cache behavior. Currently, only the - X86 backend provides target support for this feature.</li> - -<li>LLVM 2.7 has pre-alpha support for <a - href="LangRef.html#t_union">unions in LLVM IR</a>. - Unfortunately, this support is not really usable in 2.7, so if you're - interested in pushing it forward, please help contribute to LLVM mainline.</li> - -<!-- BELOW COME ACTUAL 2.8 CHANGES --> <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> @@ -629,48 +335,7 @@ release includes a few major enhancements and additions to the optimizers:</p> <ul> -<li>The inliner now merges arrays stack objects in different callees when - inlining multiple call sites into one function. This reduces the stack size - of the resultant function.</li> -<li>The -basicaa alias analysis pass (which is the default) has been improved to - be less dependent on "type safe" pointers. It can now look through bitcasts - and other constructs more aggressively, allowing better load/store - optimization.</li> -<li>The load elimination optimization in the GVN Pass [<a -href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro - blog post</a>] has been substantially improved to be more aggressive about - partial redundancy elimination and do more aggressive phi translation. Please - see the <a - href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html"> - Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation - Blog Post</a> for more details.</li> -<li>The module <a href="LangRef.html#datalayout">target data string</a> now - includes a notion of 'native' integer data types for the target. This - helps mid-level optimizations avoid promoting complex sequences of - operations to data types that are not natively supported (e.g. converting - i32 operations to i64 on 32-bit chips).</li> -<li>The mid-level optimizer is now conservative when operating on a module with - no target data. Previously, it would default to SparcV9 settings, which is - not what most people expected.</li> -<li>Jump threading is now much more aggressive at simplifying correlated - conditionals and threading blocks with otherwise complex logic. It has - subsumed the old "Conditional Propagation" pass, and -condprop has been - removed from LLVM 2.7.</li> -<li>The -instcombine pass has been refactored from being one huge file to being - a library of its own. Internally, it uses a customized IRBuilder to clean - it up and simplify it.</li> - -<li>The optimal edge profiling pass is reliable and much more complete than in - 2.6. It can be used with the llvm-prof tool but isn't wired up to the - llvm-gcc and clang command line options yet.</li> - -<li>A new experimental alias analysis implementation, -scev-aa, has been added. - It uses LLVM's Scalar Evolution implementation to do symbolic analysis of - pointer offset expressions to disambiguate pointers. It can catch a few - cases that basicaa cannot, particularly in complex loop nests.</li> - -<li>The default pass ordering has been tweaked for improved optimization - effectiveness.</li> +<li></li> </ul> @@ -685,19 +350,7 @@ href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html" <div class="doc_text"> <ul> -<li>The JIT now supports generating debug information and is compatible with -the new GDB 7.0 (and later) interfaces for registering dynamically generated -debug info.</li> - -<li>The JIT now <a href="http://llvm.org/PR5184">defaults -to compiling eagerly</a> to avoid a race condition in the lazy JIT. -Clients that still want the lazy JIT can switch it on by calling -<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li> - -<li>It is now possible to create more than one JIT instance in the same process. -These JITs can generate machine code in parallel, -although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you -still have to obey the other threading restrictions</a>.</li> +<li></li> </ul> @@ -715,49 +368,7 @@ infrastructure, which allows us to implement more aggressive algorithms and make it run faster:</p> <ul> -<li>The 'llc -asm-verbose' option (which is now the default) has been enhanced - to emit many useful comments to .s files indicating information about spill - slots and loop nest structure. This should make it much easier to read and - understand assembly files. This is wired up in llvm-gcc and clang to - the <tt>-fverbose-asm</tt> option.</li> - -<li>New LSR with "full strength reduction" mode, which can reduce address - register pressure in loops where address generation is important.</li> - -<li>A new codegen level Common Subexpression Elimination pass (MachineCSE) - is available and enabled by default. It catches redundancies exposed by - lowering.</li> -<li>A new pre-register-allocation tail duplication pass is available and enabled - by default, it can substantially improve branch prediction quality in some - cases.</li> -<li>A new sign and zero extension optimization pass (OptimizeExtsPass) - is available and enabled by default. This pass can takes advantage - architecture features like x86-64 implicit zero extension behavior and - sub-registers.</li> -<li>The code generator now supports a mode where it attempts to preserve the - order of instructions in the input code. This is important for source that - is hand scheduled and extremely sensitive to scheduling. It is compatible - with the GCC <tt>-fno-schedule-insns</tt> option.</li> -<li>The target-independent code generator now supports generating code with - arbitrary numbers of result values. Returning more values than was - previously supported is handled by returning through a hidden pointer. In - 2.7, only the X86 and XCore targets have adopted support for this - though.</li> -<li>The code generator now supports generating code that follows the - <a href="LangRef.html#callingconv">Glasgow Haskell Compiler Calling - Convention</a> and ABI.</li> -<li>The "<a href="CodeGenerator.html#selectiondag_select">DAG instruction - selection</a>" phase of the code generator has been largely rewritten for - 2.7. Previously, tblgen spit out tons of C++ code which was compiled and - linked into the target to do the pattern matching, now it emits a much - smaller table which is read by the target-independent code. The primary - advantages of this approach is that the size and compile time of various - targets is much improved. The X86 code generator shrunk by 1.5MB of code, - for example.</li> -<li>Almost the entire code generator has switched to emitting code through the - MC interfaces instead of printing textually to the .s file. This led to a - number of cleanups and speedups. In 2.7, debug an exception handling - information does not go through MC yet.</li> +<li>MachO writer works.</li> </ul> </div> @@ -771,11 +382,9 @@ it run faster:</p> </p> <ul> -<li>The X86 backend now optimizes tails calls much more aggressively for - functions that use the standard C calling convention.</li> -<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector - registers, making the code generator more aggressive in cases where scalars - and vector types are mixed.</li> +<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> @@ -792,27 +401,7 @@ it run faster:</p> <ul> -<li>The ARM backend now generates instructions in unified assembly syntax.</li> - -<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This - support differs slightly from the GCC implementation. Please see the - <a -href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html"> - ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for - helpful information if migrating code from GCC to LLVM-GCC.</li> - -<li>The ARM and Thumb code generators now use register scavenging for stack - object address materialization. This allows the use of R3 as a general - purpose register in Thumb1 code, as it was previous reserved for use in - stack address materialization. Secondly, sequential uses of the same - value will now re-use the materialized constant.</li> - -<li>The ARM backend now has good support for ARMv4 targets and has been tested - on StrongARM hardware. Previously, LLVM only supported ARMv4T and - newer chips.</li> - -<li>Atomic builtins are now supported for ARMv6 and ARMv7 (__sync_synchronize, - __sync_fetch_and_add, etc.).</li> +<li></li> </ul> @@ -831,34 +420,7 @@ href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html"> </p> <ul> -<li>The optimizer uses the new CodeMetrics class to measure the size of code. - Various passes (like the inliner, loop unswitcher, etc) all use this to make - more accurate estimates of the code size impact of various - optimizations.</li> -<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html"> - llvm/Analysis/InstructionSimplify.h</a> interface is available for doing - symbolic simplification of instructions (e.g. <tt>a+0</tt> -> <tt>a</tt>) - without requiring the instruction to exist. This centralizes a lot of - ad-hoc symbolic manipulation code scattered in various passes.</li> -<li>The optimizer now uses a new <a - href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a> - class which efficiently supports - doing unstructured SSA update operations. This centralized a bunch of code - scattered throughout various passes (e.g. jump threading, lcssa, - loop rotate, etc) for doing this sort of thing. The code generator has a - similar <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html"> - MachineSSAUpdater</a> class.</li> -<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html"> - llvm/Support/Regex.h</a> header exposes a platform independent regular - expression API. Building on this, the <a - href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports - regular exressions.</li> -<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()". - By default, this stream works the same way as "errs()", but if you pass - <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a - fixed sized circular buffer and the output is printed at the end of the - program's execution. This is helpful if you have a long lived compiler - process and you're interested in seeing snapshots in time.</li> +<li></li> </ul> @@ -873,16 +435,7 @@ href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html"> <p>Other miscellaneous features include:</p> <ul> -<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To - get this, configure LLVM with the --enable-shared option.</li> - -<li>LLVM command line tools now overwrite their output by default. Previously, - they would only do this with -f. This makes them more convenient to use, and - behave more like standard unix tools.</li> - -<li>The opt and llc tools now autodetect whether their input is a .ll or .bc - file, and automatically do the right thing. This means you don't need to - explicitly use the llvm-as tool for most things.</li> +<li></li> </ul> </div> @@ -896,48 +449,18 @@ href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html"> <div class="doc_text"> <p>If you're already an LLVM user or developer with out-of-tree changes based -on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading +on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading from the previous release.</p> <ul> -<li> -The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier -("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling -profiling ("rsprofiling") passes have all been removed. They were not being -actively maintained and had substantial problems. If you are interested in -these components, you are welcome to ressurect them from SVN, fix the -correctness problems, and resubmit them to mainline.</li> - -<li>LLVM now defaults to building most libraries with RTTI turned off, providing -a code size reduction. Packagers who are interested in building LLVM to support -plugins that require RTTI information should build with "make REQUIRE_RTTI=1" -and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a> -document.</li> - -<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even -if you have it installed. This makes it more likely that an LLVM built on one -system will work when copied to a similar system. To use <tt>libffi</tt>, -configure with <tt>--enable-libffi</tt>.</li> - -<li>Debug information uses a completely different representation, an LLVM 2.6 -.bc file should work with LLVM 2.7, but debug info won't come forward.</li> - -<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed, - along with LowerAllocations pass. Now you should just use a call to the - malloc and free functions in libc. These calls are optimized as well as - the old instructions were.</li> +<li>.</li> </ul> <p>In addition, many APIs have changed in this release. Some of the major LLVM API changes are:</p> <ul> - -<li>The <tt>add</tt>, <tt>sub</tt>, and <tt>mul</tt> instructions no longer -support floating-point operands. The <tt>fadd</tt>, <tt>fsub</tt>, and -<tt>fmul</tt> instructions should be used for this purpose instead.</li> - </ul> </div> @@ -1016,8 +539,7 @@ href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p> <li>The MSIL, 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. The MachO writer is experimental, and - works much better in mainline SVN.</li> + supported value for this option. XXX Update me</li> </ul> </div> @@ -1034,8 +556,6 @@ href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p> 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>The X86 backend generates inefficient floating point code when configured - to generate code for systems that don't have SSE2.</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 |