diff options
| author | Jeffrey Yasskin <jyasskin@google.com> | 2010-01-28 01:14:43 +0000 |
|---|---|---|
| committer | Jeffrey Yasskin <jyasskin@google.com> | 2010-01-28 01:14:43 +0000 |
| commit | 8ee1b0a7fc44d8e19a3974697b1a152cb6fe7e1c (patch) | |
| tree | b555a1ab0db95ae208f4bc2bb136ac9b4adf39c0 /docs/ReleaseNotes.html | |
| parent | d2f089fa97185c4659d22de5dc7bb36a7c54b05a (diff) | |
| download | external_llvm-8ee1b0a7fc44d8e19a3974697b1a152cb6fe7e1c.zip external_llvm-8ee1b0a7fc44d8e19a3974697b1a152cb6fe7e1c.tar.gz external_llvm-8ee1b0a7fc44d8e19a3974697b1a152cb6fe7e1c.tar.bz2 | |
Truncate the release notes so they're ready to accumulate notes for the 2.7 release.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94720 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs/ReleaseNotes.html')
| -rw-r--r-- | docs/ReleaseNotes.html | 483 |
1 files changed, 45 insertions, 438 deletions
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index f3d87c6..8df6cfc 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -4,17 +4,17 @@ <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <link rel="stylesheet" href="llvm.css" type="text/css"> - <title>LLVM 2.6 Release Notes</title> + <title>LLVM 2.7 Release Notes</title> </head> <body> -<div class="doc_title">LLVM 2.6 Release Notes</div> +<div class="doc_title">LLVM 2.7 Release Notes</div> <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 2.6</a></li> - <li><a href="#whatsnew">What's New in LLVM 2.6?</a></li> + <li><a href="#externalproj">External Projects Using LLVM 2.7</a></li> + <li><a href="#whatsnew">What's New in LLVM 2.7?</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></li> @@ -25,6 +25,12 @@ <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 2.7 +release.<br> +You may prefer the +<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.6 +Release Notes</a>.</h1> + <!-- *********************************************************************** --> <div class="doc_section"> <a name="intro">Introduction</a> @@ -34,7 +40,7 @@ <div class="doc_text"> <p>This document contains the release notes for the LLVM Compiler -Infrastructure, release 2.6. Here we describe the status of LLVM, including +Infrastructure, release 2.7. 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> @@ -63,7 +69,7 @@ Almost dead code. --> -<!-- Unfinished features in 2.6: +<!-- Features that need text if they're finished for 2.7: gcc plugin. strong phi elim variable debug info for optimized code @@ -94,7 +100,7 @@ Almost dead code. <div class="doc_text"> <p> -The LLVM 2.6 distribution currently consists of code from the core LLVM +The LLVM 2.7 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 @@ -111,31 +117,12 @@ development. Here we include updates on these subprojects. <div class="doc_text"> -<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build -a set of new 'LLVM native' front-end technologies for the C family of languages. -LLVM 2.6 is the first release to officially include Clang, and it provides a -production quality C and Objective-C compiler. If you are interested in <a -href="http://clang.llvm.org/performance.html">fast compiles</a> and -<a href="http://clang.llvm.org/diagnostics.html">good diagnostics</a>, we -encourage you to try it out. Clang currently compiles typical Objective-C code -3x faster than GCC and compiles C code about 30% faster than GCC at -O0 -g -(which is when the most pressure is on the frontend).</p> - -<p>In addition to supporting these languages, C++ support is also <a -href="http://clang.llvm.org/cxx_status.html">well under way</a>, and mainline -Clang is able to parse the libstdc++ 4.2 headers and even codegen simple apps. -If you are interested in Clang C++ support or any other Clang feature, we -strongly encourage you to get involved on the <a -href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing -list</a>.</p> - -<p>In the LLVM 2.6 time-frame, the Clang team has made many improvements:</p> +<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p> + +<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p> <ul> -<li>C and Objective-C support are now considered production quality.</li> -<li>AuroraUX, FreeBSD and OpenBSD are now supported.</li> -<li>Most of Objective-C 2.0 is now supported with the GNU runtime.</li> -<li>Many many bugs are fixed and lots of features have been added.</li> +<li>...</li> </ul> </div> @@ -146,24 +133,13 @@ list</a>.</p> <div class="doc_text"> -<p>Previously announced in the 2.4 and 2.5 LLVM releases, the Clang project also +<p>Previously announced in the 2.4, 2.5, and 2.6 LLVM releases, the Clang project also includes an early stage static source code analysis tool for <a href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a> in C and Objective-C programs. The tool performs checks to find bugs that occur on a specific path within a program.</p> -<p>In the LLVM 2.6 time-frame, the analyzer core has undergone several important -improvements and cleanups and now includes a new <em>Checker</em> interface that -is intended to eventually serve as a basis for domain-specific checks. Further, -in addition to generating HTML files for reporting analysis results, the -analyzer can now also emit bug reports in a structured XML format that is -intended to be easily readable by other programs.</p> - -<p>The set of checks performed by the static analyzer continues to expand, and -future plans for the tool include full source-level inter-procedural analysis -and deeper checks such as buffer overrun detection. There are many opportunities -to extend and enhance the static analyzer, and anyone interested in working on -this project is encouraged to get involved!</p> +<p>In the LLVM 2.7 time-frame, the analyzer core has ...</p> </div> @@ -180,20 +156,13 @@ implementation of the CLI) using LLVM for static and just-in-time compilation.</p> <p> -VMKit version 0.26 builds with LLVM 2.6 and you can find it on its +VMKit version ?? builds with LLVM 2.7 and you can find it on its <a href="http://vmkit.llvm.org/releases/">web page</a>. The release includes bug fixes, cleanup and new features. The major changes are:</p> <ul> -<li>A new llcj tool to generate shared libraries or executables of Java - files.</li> -<li>Cooperative garbage collection. </li> -<li>Fast subtype checking (paper from Click et al [JGI'02]). </li> -<li>Implementation of a two-word header for Java objects instead of the original - three-word header. </li> -<li>Better Java specification-compliance: division by zero checks, stack - overflow checks, finalization and references support. </li> +<li>...</li> </ul> </div> @@ -249,22 +218,7 @@ KLEE.</p> The goal of <a href="http://dragonegg.llvm.org/">DragonEgg</a> is to make gcc-4.5 act like llvm-gcc without requiring any gcc modifications whatsoever. <a href="http://dragonegg.llvm.org/">DragonEgg</a> is a shared library (dragonegg.so) -that is loaded by gcc at runtime. It uses the new gcc plugin architecture to -disable the GCC optimizers and code generators, and schedule the LLVM optimizers -and code generators (or direct output of LLVM IR) instead. Currently only Linux -and Darwin are supported, and only on x86-32 and x86-64. It should be easy to -add additional unix-like architectures and other processor families. In theory -it should be possible to use <a href="http://dragonegg.llvm.org/">DragonEgg</a> -with any language supported by gcc, however only C and Fortran work well for the -moment. Ada and C++ work to some extent, while Java, Obj-C and Obj-C++ are so -far entirely untested. Since gcc-4.5 has not yet been released, neither has -<a href="http://dragonegg.llvm.org/">DragonEgg</a>. To build -<a href="http://dragonegg.llvm.org/">DragonEgg</a> you will need to check out the -development versions of <a href="http://gcc.gnu.org/svn.html/"> gcc</a>, -<a href="http://llvm.org/docs/GettingStarted.html#checkout">llvm</a> and -<a href="http://dragonegg.llvm.org/">DragonEgg</a> from their respective -subversion repositories, and follow the instructions in the -<a href="http://dragonegg.llvm.org/">DragonEgg</a> README. +that is loaded by gcc at runtime. It ... </p> </div> @@ -277,29 +231,7 @@ subversion repositories, and follow the instructions in the <div class="doc_text"> <p> -The LLVM Machine Code (MC) Toolkit project is a (very early) effort to build -better tools for dealing with machine code, object file formats, etc. The idea -is to be able to generate most of the target specific details of assemblers and -disassemblers from existing LLVM target .td files (with suitable enhancements), -and to build infrastructure for reading and writing common object file formats. -One of the first deliverables is to build a full assembler and integrate it into -the compiler, which is predicted to substantially reduce compile time in some -scenarios. -</p> - -<p>In the LLVM 2.6 timeframe, the MC framework has grown to the point where it -can reliably parse and pretty print (with some encoding information) a -darwin/x86 .s file successfully, and has the very early phases of a Mach-O -assembler in progress. Beyond the MC framework itself, major refactoring of the -LLVM code generator has started. The idea is to make the code generator reason -about the code it is producing in a much more semantic way, rather than a -textual way. For example, the code generator now uses MCSection objects to -represent section assignments, instead of text strings that print to .section -directives.</p> - -<p>MC is an early and ongoing project that will hopefully continue to lead to -many improvements in the code generator and build infrastructure useful for many -other situations. +The LLVM Machine Code (MC) Toolkit project is ... </p> </div> @@ -307,7 +239,7 @@ other situations. <!-- *********************************************************************** --> <div class="doc_section"> - <a name="externalproj">External Open Source Projects Using LLVM 2.6</a> + <a name="externalproj">External Open Source Projects Using LLVM 2.7</a> </div> <!-- *********************************************************************** --> @@ -315,7 +247,7 @@ other situations. <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 2.6.</p> + projects that have already been updated to work with LLVM 2.7.</p> </div> @@ -376,8 +308,8 @@ 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 0.31 and later have been tested and are known to work with -LLVM 2.6 (and continue to work with older LLVM releases >= 2.3 as well). +<p>Pure versions ??? and later have been tested and are known to work with +LLVM 2.7 (and continue to work with older LLVM releases >= 2.3 as well). </p> </div> @@ -460,7 +392,7 @@ code. <!-- *********************************************************************** --> <div class="doc_section"> - <a name="whatsnew">What's New in LLVM 2.6?</a> + <a name="whatsnew">What's New in LLVM 2.7?</a> </div> <!-- *********************************************************************** --> @@ -480,28 +412,10 @@ in this section. <div class="doc_text"> -<p>LLVM 2.6 includes several major new capabilities:</p> +<p>LLVM 2.7 includes several major new capabilities:</p> <ul> -<li>New <a href="#compiler-rt">compiler-rt</a>, <A href="#klee">KLEE</a> - and <a href="#mc">machine code toolkit</a> sub-projects.</li> -<li>Debug information now includes line numbers when optimizations are enabled. - This allows statistical sampling tools like OProfile and Shark to map - samples back to source lines.</li> -<li>LLVM now includes new experimental backends to support the MSP430, SystemZ - and BlackFin architectures.</li> -<li>LLVM supports a new <a href="GoldPlugin.html">Gold Linker Plugin</a> which - enables support for <a href="LinkTimeOptimization.html">transparent - link-time optimization</a> on ELF targets when used with the Gold binutils - linker.</li> -<li>LLVM now supports doing optimization and code generation on multiple - threads. Please see the <a href="ProgrammersManual.html#threading">LLVM - Programmer's Manual</a> for more information.</li> -<li>LLVM now has experimental support for <a - href="http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt">embedded - metadata</a> in LLVM IR, though the implementation is not guaranteed to be - final and the .bc file format may change in future releases. Debug info - does not yet use this format in LLVM 2.6.</li> +<li>...</li> </ul> </div> @@ -516,50 +430,7 @@ in this section. expose new optimization opportunities:</p> <ul> -<li>The <a href="LangRef.html#i_add">add</a>, <a - href="LangRef.html#i_sub">sub</a> and <a href="LangRef.html#i_mul">mul</a> - instructions have been split into integer and floating point versions (like - divide and remainder), introducing new <a - href="LangRef.html#i_fadd">fadd</a>, <a href="LangRef.html#i_fsub">fsub</a>, - and <a href="LangRef.html#i_fmul">fmul</a> instructions.</li> -<li>The <a href="LangRef.html#i_add">add</a>, <a - href="LangRef.html#i_sub">sub</a> and <a href="LangRef.html#i_mul">mul</a> - instructions now support optional "nsw" and "nuw" bits which indicate that - the operation is guaranteed to not overflow (in the signed or - unsigned case, respectively). This gives the optimizer more information and - can be used for things like C signed integer values, which are undefined on - overflow.</li> -<li>The <a href="LangRef.html#i_sdiv">sdiv</a> instruction now supports an - optional "exact" flag which indicates that the result of the division is - guaranteed to have a remainder of zero. This is useful for optimizing pointer - subtraction in C.</li> -<li>The <a href="LangRef.html#i_getelementptr">getelementptr</a> instruction now - supports arbitrary integer index values for array/pointer indices. This - allows for better code generation on 16-bit pointer targets like PIC16.</li> -<li>The <a href="LangRef.html#i_getelementptr">getelementptr</a> instruction now - supports an "inbounds" optimization hint that tells the optimizer that the - pointer is guaranteed to be within its allocated object.</li> -<li>LLVM now support a series of new linkage types for global values which allow - for better optimization and new capabilities: - <ul> - <li><a href="LangRef.html#linkage_linkonce">linkonce_odr</a> and - <a href="LangRef.html#linkage_weak">weak_odr</a> have the same linkage - semantics as the non-"odr" linkage types. The difference is that these - linkage types indicate that all definitions of the specified function - are guaranteed to have the same semantics. This allows inlining - templates functions in C++ but not inlining weak functions in C, - which previously both got the same linkage type.</li> - <li><a href="LangRef.html#linkage_available_externally">available_externally - </a> is a new linkage type that gives the optimizer visibility into the - definition of a function (allowing inlining and side effect analysis) - but that does not cause code to be generated. This allows better - optimization of "GNU inline" functions, extern templates, etc.</li> - <li><a href="LangRef.html#linkage_linker_private">linker_private</a> is a - new linkage type (which is only useful on Mac OS X) that is used for - some metadata generation and other obscure things.</li> - </ul></li> -<li>Finally, target-specific intrinsics can now return multiple values, which - is useful for modeling target operations with multiple results.</li> +<li>...</li> </ul> </div> @@ -576,23 +447,7 @@ release includes a few major enhancements and additions to the optimizers:</p> <ul> -<li>The <a href="Passes.html#scalarrepl">Scalar Replacement of Aggregates</a> - pass has many improvements that allow it to better promote vector unions, - variables which are memset, and much more strange code that can happen to - do bitfield accesses to register operations. An interesting change is that - it now produces "unusual" integer sizes (like i1704) in some cases and lets - other optimizers clean things up.</li> -<li>The <a href="Passes.html#loop-reduce">Loop Strength Reduction</a> pass now - promotes small integer induction variables to 64-bit on 64-bit targets, - which provides a major performance boost for much numerical code. It also - promotes shorts to int on 32-bit hosts, etc. LSR now also analyzes pointer - expressions (e.g. getelementptrs), as well as integers.</li> -<li>The <a href="Passes.html#gvn">GVN</a> pass now eliminates partial - redundancies of loads in simple cases.</li> -<li>The <a href="Passes.html#inline">Inliner</a> now reuses stack space when - inlining similar arrays from multiple callees into one caller.</li> -<li>LLVM includes a new experimental Static Single Information (SSI) - construction pass.</li> +<li>...</li> </ul> @@ -607,17 +462,7 @@ release includes a few major enhancements and additions to the optimizers:</p> <div class="doc_text"> <ul> -<li>LLVM has a new "EngineBuilder" class which makes it more obvious how to - set up and configure an ExecutionEngine (a JIT or interpreter).</li> -<li>The JIT now supports generating more than 16M of code.</li> -<li>When configured with <tt>--with-oprofile</tt>, the JIT can now inform - OProfile about JIT'd code, allowing OProfile to get line number and function - name information for JIT'd functions.</li> -<li>When "libffi" is available, the LLVM interpreter now uses it, which supports - calling almost arbitrary external (natively compiled) functions.</li> -<li>Clients of the JIT can now register a 'JITEventListener' object to receive - callbacks when the JIT emits or frees machine code. The OProfile support - uses this mechanism.</li> +<li>...</li> </ul> </div> @@ -635,54 +480,7 @@ it run faster:</p> <ul> -<li>The <tt>llc -asm-verbose</tt> option (exposed from llvm-gcc as <tt>-dA</tt> - and clang as <tt>-fverbose-asm</tt> or <tt>-dA</tt>) now adds a lot of - useful information in comments to - the generated .s file. This information includes location information (if - built with <tt>-g</tt>) and loop nest information.</li> -<li>The code generator now supports a new MachineVerifier pass which is useful - for finding bugs in targets and codegen passes.</li> -<li>The Machine LICM is now enabled by default. It hoists instructions out of - loops (such as constant pool loads, loads from read-only stubs, vector - constant synthesization code, etc.) and is currently configured to only do - so when the hoisted operation can be rematerialized.</li> -<li>The Machine Sinking pass is now enabled by default. This pass moves - side-effect free operations down the CFG so that they are executed on fewer - paths through a function.</li> -<li>The code generator now performs "stack slot coloring" of register spills, - which allows spill slots to be reused. This leads to smaller stack frames - in cases where there are lots of register spills.</li> -<li>The register allocator has many improvements to take better advantage of - commutable operations, various spiller peephole optimizations, and can now - coalesce cross-register-class copies.</li> -<li>Tblgen now supports multiclass inheritance and a number of new string and - list operations like <tt>!(subst)</tt>, <tt>!(foreach)</tt>, <tt>!car</tt>, - <tt>!cdr</tt>, <tt>!null</tt>, <tt>!if</tt>, <tt>!cast</tt>. - These make the .td files more expressive and allow more aggressive factoring - of duplication across instruction patterns.</li> -<li>Target-specific intrinsics can now be added without having to hack VMCore to - add them. This makes it easier to maintain out-of-tree targets.</li> -<li>The instruction selector is better at propagating information about values - (such as whether they are sign/zero extended etc.) across basic block - boundaries.</li> -<li>The SelectionDAG datastructure has new nodes for representing buildvector - and <a href="http://llvm.org/PR2957">vector shuffle</a> operations. This - makes operations and pattern matching more efficient and easier to get - right.</li> -<li>The Prolog/Epilog Insertion Pass now has experimental support for performing - the "shrink wrapping" optimization, which moves spills and reloads around in - the CFG to avoid doing saves on paths that don't need them.</li> -<li>LLVM includes new experimental support for writing ELF .o files directly - from the compiler. It works well for many simple C testcases, but doesn't - support exception handling, debug info, inline assembly, etc.</li> -<li>Targets can now specify register allocation hints through - <tt>MachineRegisterInfo::setRegAllocationHint</tt>. A regalloc hint consists - of hint type and physical register number. A hint type of zero specifies a - register allocation preference. Other hint type values are target specific - which are resolved by <tt>TargetRegisterInfo::ResolveRegAllocHint</tt>. An - example is the ARM target which uses register hints to request that the - register allocator provide an even / odd register pair to two virtual - registers.</li> +<li>...</li> </ul> </div> @@ -697,31 +495,7 @@ it run faster:</p> <ul> -<li>SSE 4.2 builtins are now supported.</li> -<li>GCC-compatible soft float modes are now supported, which are typically used - by OS kernels.</li> -<li>X86-64 now models implicit zero extensions better, which allows the code - generator to remove a lot of redundant zexts. It also models the 8-bit "H" - registers as subregs, which allows them to be used in some tricky - situations.</li> -<li>X86-64 now supports the "local exec" and "initial exec" thread local storage - model.</li> -<li>The vector forms of the <a href="LangRef.html#i_icmp">icmp</a> and <a - href="LangRef.html#i_fcmp">fcmp</a> instructions now select to efficient - SSE operations.</li> -<li>Support for the win64 calling conventions have improved. The primary - missing feature is support for varargs function definitions. It seems to - work well for many win64 JIT purposes.</li> -<li>The X86 backend has preliminary support for <a - href="CodeGenerator.html#x86_memory">mapping address spaces to segment - register references</a>. This allows you to write GS or FS relative memory - accesses directly in LLVM IR for cases where you know exactly what you're - doing (such as in an OS kernel). There are some known problems with this - support, but it works in simple cases.</li> -<li>The X86 code generator has been refactored to move all global variable - reference logic to one place - (<tt>X86Subtarget::ClassifyGlobalReference</tt>) which - makes it easier to reason about.</li> +<li>...</li> </ul> @@ -737,11 +511,7 @@ it run faster:</p> </p> <ul> -<li>Support for floating-point, indirect function calls, and - passing/returning aggregate types to functions. -<li>The code generator is able to generate debug info into output COFF files. -<li>Support for placing an object into a specific section or at a specific - address in memory.</li> +<li>...</li> </ul> <p>Things not yet supported:</p> @@ -764,22 +534,9 @@ it run faster:</p> <ul> -<li>Preliminary support for processors, such as the Cortex-A8 and Cortex-A9, -that implement version v7-A of the ARM architecture. The ARM backend now -supports both the Thumb2 and Advanced SIMD (Neon) instruction sets.</li> - -<li>The AAPCS-VFP "hard float" calling conventions are also supported with the -<tt>-float-abi=hard</tt> flag.</li> - -<li>The ARM calling convention code is now tblgen generated instead of resorting - to C++ code.</li> +<li>...</li> </ul> -<p>These features are still somewhat experimental -and subject to change. The Neon intrinsics, in particular, may change in future -releases of LLVM. ARMv7 support has progressed a lot on top of tree since 2.6 -branched.</p> - </div> @@ -793,11 +550,7 @@ branched.</p> </p> <ul> -<li>Mips now supports O32 Calling Convention.</li> -<li>Many improvements to the 32-bit PowerPC SVR4 ABI (used on powerpc-linux) - support, lots of bugs fixed.</li> -<li>Added support for the 64-bit PowerPC SVR4 ABI (used on powerpc64-linux). - Needs more testing.</li> +<li>...</li> </ul> </div> @@ -814,40 +567,7 @@ branched.</p> </p> <ul> -<li>New <a href="http://llvm.org/doxygen/PrettyStackTrace_8h-source.html"> - <tt>PrettyStackTrace</tt> class</a> allows crashes of llvm tools (and applications - that integrate them) to provide more detailed indication of what the - compiler was doing at the time of the crash (e.g. running a pass). - At the top level for each LLVM tool, it includes the command line arguments. - </li> -<li>New <a href="http://llvm.org/doxygen/StringRef_8h-source.html">StringRef</a> - and <a href="http://llvm.org/doxygen/Twine_8h-source.html">Twine</a> classes - make operations on character ranges and - string concatenation to be more efficient. <tt>StringRef</tt> is just a <tt>const - char*</tt> with a length, <tt>Twine</tt> is a light-weight rope.</li> -<li>LLVM has new <tt>WeakVH</tt>, <tt>AssertingVH</tt> and <tt>CallbackVH</tt> - classes, which make it easier to write LLVM IR transformations. <tt>WeakVH</tt> - is automatically drops to null when the referenced <tt>Value</tt> is deleted, - and is updated across a <tt>replaceAllUsesWith</tt> operation. - <tt>AssertingVH</tt> aborts the program if the - referenced value is destroyed while it is being referenced. <tt>CallbackVH</tt> - is a customizable class for handling value references. See <a - href="http://llvm.org/doxygen/ValueHandle_8h-source.html">ValueHandle.h</a> - for more information.</li> -<li>The new '<a href="http://llvm.org/doxygen/Triple_8h-source.html">Triple - </a>' class centralizes a lot of logic that reasons about target - triples.</li> -<li>The new '<a href="http://llvm.org/doxygen/ErrorHandling_8h-source.html"> - llvm_report_error()</a>' set of APIs allows tools to embed the LLVM - optimizer and backend and recover from previously unrecoverable errors.</li> -<li>LLVM has new abstractions for <a - href="http://llvm.org/doxygen/Atomic_8h-source.html">atomic operations</a> - and <a href="http://llvm.org/doxygen/RWMutex_8h-source.html">reader/writer - locks</a>.</li> -<li>LLVM has new <a href="http://llvm.org/doxygen/SourceMgr_8h-source.html"> - <tt>SourceMgr</tt> and <tt>SMLoc</tt> classes</a> which implement caret - diagnostics and basic include stack processing for simple parsers. It is - used by tablegen, llvm-mc, the .ll parser and FileCheck.</li> +<li>...</li> </ul> @@ -862,32 +582,7 @@ branched.</p> <p>Other miscellaneous features include:</p> <ul> -<li>LLVM now includes a new internal '<a - href="http://llvm.org/cmds/FileCheck.html">FileCheck</a>' tool which allows - writing much more accurate regression tests that run faster. Please see the - <a href="TestingGuide.html#FileCheck">FileCheck section of the Testing - Guide</a> for more information.</li> -<li>LLVM profile information support has been significantly improved to produce -correct use counts, and has support for edge profiling with reduced runtime -overhead. Combined, the generated profile information is both more correct and -imposes about half as much overhead (2.6. from 12% to 6% overhead on SPEC -CPU2000).</li> -<li>The C bindings (in the llvm/include/llvm-c directory) include many newly - supported APIs.</li> -<li>LLVM 2.6 includes a brand new experimental LLVM bindings to the Ada2005 - programming language.</li> - -<li>The LLVMC driver has several new features: - <ul> - <li>Dynamic plugins now work on Windows.</li> - <li>New option property: init. Makes possible to provide default values for - options defined in plugins (interface to <tt>cl::init</tt>).</li> - <li>New example: Skeleton, shows how to create a standalone LLVMC-based - driver.</li> - <li>New example: mcc16, a driver for the PIC16 toolchain.</li> - </ul> -</li> - +<li>...</li> </ul> </div> @@ -901,24 +596,11 @@ CPU2000).</li> <div class="doc_text"> <p>If you're already an LLVM user or developer with out-of-tree changes based -on LLVM 2.5, this section lists some "gotchas" that you may run into upgrading +on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading from the previous release.</p> <ul> -<li>The Itanium (IA64) backend has been removed. It was not actively supported - and had bitrotted.</li> -<li>The BigBlock register allocator has been removed, it had also bitrotted.</li> -<li>The C Backend (<tt>-march=c</tt>) is no longer considered part of the LLVM release -criteria. We still want it to work, but no one is maintaining it and it lacks -support for arbitrary precision integers and other important IR features.</li> - -<li>All LLVM tools now default to overwriting their output file, behaving more - like standard unix tools. Previously, this only happened with the '<tt>-f</tt>' - option.</li> -<li>LLVM build now builds all libraries as .a files instead of some - libraries as relinked .o files. This requires some APIs like - InitializeAllTargets.h. - </li> +<li>...</li> </ul> @@ -926,82 +608,7 @@ support for arbitrary precision integers and other important IR features.</li> API changes are:</p> <ul> -<li>All uses of <tt>hash_set</tt> and <tt>hash_map</tt> have been removed from - the LLVM tree and the wrapper headers have been removed.</li> -<li>The llvm/Streams.h and <tt>DOUT</tt> member of Debug.h have been removed. The - <tt>llvm::Ostream</tt> class has been completely removed and replaced with - uses of <tt>raw_ostream</tt>.</li> -<li>LLVM's global uniquing tables for <tt>Type</tt>s and <tt>Constant</tt>s have - been privatized into members of an <tt>LLVMContext</tt>. A number of APIs - now take an <tt>LLVMContext</tt> as a parameter. To smooth the transition - for clients that will only ever use a single context, the new - <tt>getGlobalContext()</tt> API can be used to access a default global - context which can be passed in any and all cases where a context is - required. -<li>The <tt>getABITypeSize</tt> methods are now called <tt>getAllocSize</tt>.</li> -<li>The <tt>Add</tt>, <tt>Sub</tt> and <tt>Mul</tt> operators are no longer - overloaded for floating-point types. Floating-point addition, subtraction - and multiplication are now represented with new operators <tt>FAdd</tt>, - <tt>FSub</tt> and <tt>FMul</tt>. In the <tt>IRBuilder</tt> API, - <tt>CreateAdd</tt>, <tt>CreateSub</tt>, <tt>CreateMul</tt> and - <tt>CreateNeg</tt> should only be used for integer arithmetic now; - <tt>CreateFAdd</tt>, <tt>CreateFSub</tt>, <tt>CreateFMul</tt> and - <tt>CreateFNeg</tt> should now be used for floating-point arithmetic.</li> -<li>The <tt>DynamicLibrary</tt> class can no longer be constructed, its functionality has - moved to static member functions.</li> -<li><tt>raw_fd_ostream</tt>'s constructor for opening a given filename now - takes an extra <tt>Force</tt> argument. If <tt>Force</tt> is set to - <tt>false</tt>, an error will be reported if a file with the given name - already exists. If <tt>Force</tt> is set to <tt>true</tt>, the file will - be silently truncated (which is the behavior before this flag was - added).</li> -<li><tt>SCEVHandle</tt> no longer exists, because reference counting is no - longer done for <tt>SCEV*</tt> objects, instead <tt>const SCEV*</tt> - should be used.</li> - -<li>Many APIs, notably <tt>llvm::Value</tt>, now use the <tt>StringRef</tt> -and <tt>Twine</tt> classes instead of passing <tt>const char*</tt> -or <tt>std::string</tt>, as described in -the <a href="ProgrammersManual.html#string_apis">Programmer's Manual</a>. Most -clients should be unaffected by this transition, unless they are used to -<tt>Value::getName()</tt> returning a string. Here are some tips on updating to -2.6: - <ul> - <li><tt>getNameStr()</tt> is still available, and matches the old - behavior. Replacing <tt>getName()</tt> calls with this is an safe option, - although more efficient alternatives are now possible.</li> - - <li>If you were just relying on <tt>getName()</tt> being able to be sent to - a <tt>std::ostream</tt>, consider migrating - to <tt>llvm::raw_ostream</tt>.</li> - - <li>If you were using <tt>getName().c_str()</tt> to get a <tt>const - char*</tt> pointer to the name, you can use <tt>getName().data()</tt>. - Note that this string (as before), may not be the entire name if the - name contains embedded null characters.</li> - - <li>If you were using <tt>operator +</tt> on the result of <tt>getName()</tt> and - treating the result as an <tt>std::string</tt>, you can either - use <tt>Twine::str</tt> to get the result as an <tt>std::string</tt>, or - could move to a <tt>Twine</tt> based design.</li> - - <li><tt>isName()</tt> should be replaced with comparison - against <tt>getName()</tt> (this is now efficient). - </ul> -</li> - -<li>The registration interfaces for backend Targets has changed (what was -previously <tt>TargetMachineRegistry</tt>). For backend authors, see the <a -href="WritingAnLLVMBackend.html#TargetRegistration">Writing An LLVM Backend</a> -guide. For clients, the notable API changes are: - <ul> - <li><tt>TargetMachineRegistry</tt> has been renamed - to <tt>TargetRegistry</tt>.</li> - - <li>Clients should move to using the <tt>TargetRegistry::lookupTarget()</tt> - function to find targets.</li> - </ul> -</li> +<li>...</li> </ul> </div> @@ -1055,8 +662,8 @@ there isn't already one.</p> <li>The llvm-gcc bootstrap will fail with some versions of binutils (e.g. 2.15) with a message of "<tt><a href="http://llvm.org/PR5004">Error: can not do 8 byte pc-relative relocation</a></tt>" when building C++ code. We intend to - fix this on mainline, but a workaround for 2.6 is to upgrade to binutils - 2.17 or later.</li> + fix this on mainline, but a workaround is to upgrade to binutils 2.17 or + later.</li> <li>LLVM will not correctly compile on Solaris and/or OpenSolaris using the stock GCC 3.x.x series 'out the box', |