X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=docs%2FReleaseNotes.html;h=c960f555ee6fec9ed5bb969fefac55841448dd22;hb=415326b4edcc967dfb03c5ab41923b195e7c3cb1;hp=2c7e232e7b7273186c4a81c0e54a912228bb6ecb;hpb=0a43a0e9b302580f6c0d7e3daf9572bd5c2a839d;p=oota-llvm.git diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index 2c7e232e7b7..c960f555ee6 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -4,16 +4,17 @@ - LLVM 2.4 Release Notes + LLVM 2.7 Release Notes -
LLVM 2.4 Release Notes
+
LLVM 2.7 Release Notes
  1. Introduction
  2. Sub-project Status Update
  3. -
  4. What's New in LLVM?
  5. +
  6. External Projects Using LLVM 2.7
  7. +
  8. What's New in LLVM 2.7?
  9. Installation Instructions
  10. Portability and Supported Platforms
  11. Known Problems
  12. @@ -24,6 +25,12 @@

    Written by the LLVM Team

    +

    These are in-progress notes for the upcoming LLVM 2.7 +release.
    +You may prefer the +LLVM 2.6 +Release Notes.

    +
    Introduction @@ -33,9 +40,9 @@

    This document contains the release notes for the LLVM Compiler -Infrastructure, release 2.4. 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 LLVM releases web site.

    For more information about LLVM, including information about the latest @@ -50,19 +57,40 @@ current one. To see the release notes for a specific release, please see the releases page.

    - - + + + + Logo web page. + llvm devmtg + compiler_rt + KLEE web page at klee.llvm.org + Many new papers added to /pubs/ + Mention gcc plugin. + + -->
    @@ -72,12 +100,11 @@ current one. To see the release notes for a specific release, please see the

    -The LLVM 2.4 distribution currently consists of code from the core LLVM -repository (which roughly includes the LLVM optimizers, code generators and -supporting tools) and the llvm-gcc repository. In addition to this code, the -LLVM Project includes other sub-projects that are in development. The two which -are the most actively developed are the Clang Project and -the VMKit Project. +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 +development. Here we include updates on these subprojects.

    @@ -90,41 +117,13 @@ the VMKit Project.
    -

    The Clang project is an effort to build -a set of new 'LLVM native' front-end technologies for the LLVM optimizer -and code generator. Clang is continuing to make major strides forward in all -areas. Its C and Objective-C parsing support is very solid, and the code -generation support is far enough along to build many C applications. While not -yet production quality, it is progressing very nicely. In addition, C++ -front-end work has started to make significant progress.

    - -

    Clang, in conjunction with the ccc driver, is now usable as a -replacement for gcc for building some small- to medium-sized C applications. -Additionally, Clang now has code generation support for Objective-C on Mac OS X -platform. Major highlights include:

    +

    The Clang project is ...

    -
      -
    • Clang/ccc pass almost all of the LLVM test suite on Mac OS X and Linux -on the 32-bit x86 architecture. This includes significant C -applications such as sqlite3, -lua, and -Clam AntiVirus.
    • - -
    • Clang can build the majority of Objective-C examples shipped with the -Mac OS X Developer Tools.
    • -
    - -

    Clang code generation still needs considerable testing and development, -however. Some areas under active development include:

    +

    In the LLVM 2.7 time-frame, the Clang team has made many improvements:

      -
    • Improved support for C and Objective-C features, for example - variable-length arrays, va_arg, exception handling (Obj-C), and garbage - collection (Obj-C).
    • -
    • ABI compatibility, especially for platforms other than 32-bit - x86.
    • +
    • ...
    -
    @@ -134,28 +133,13 @@ however. Some areas under active development include:

    -

    The Clang project also includes an early stage static source code analysis -tool for automatically -finding bugs in C and Objective-C programs. The tool performs a growing set -of checks to find bugs that occur on a specific path within a program. Examples -of bugs the tool finds include logic errors such as null dereferences, -violations of various API rules, dead code, and potential memory leaks in -Objective-C programs. Since its inception, public feedback on the tool has been -extremely positive, and conservative estimates put the number of real bugs it -has found in industrial-quality software on the order of thousands.

    +

    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 automatically finding bugs +in C and Objective-C programs. The tool performs checks to find +bugs that occur on a specific path within a program.

    -

    The tool also provides a simple web GUI to inspect potential bugs found by -the tool. While still early in development, the GUI illustrates some of the key -features of Clang: accurate source location information, which is used by the -GUI to highlight specific code expressions that relate to a bug (including those -that span multiple lines); and built-in knowledge of macros, which is used to -perform inline expansion of macros within the GUI itself.

    - -

    The set of checks performed by the static analyzer is gradually expanding, -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!

    +

    In the LLVM 2.7 time-frame, the analyzer core has ...

    @@ -167,166 +151,286 @@ in working on this project is encouraged to get involved!

    The VMKit project is an implementation of -a JVM and a CLI Virtual Machines (Microsoft .NET is an -implementation of the CLI) using the Just-In-Time compiler of LLVM.

    +a JVM and a CLI Virtual Machine (Microsoft .NET is an +implementation of the CLI) using LLVM for static and just-in-time +compilation.

    -

    Following LLVM 2.4, VMKit has its first release 0.24 that you can find on its -webpage. The release includes +

    +VMKit version ?? builds with LLVM 2.7 and you can find it on its +web page. The release includes bug fixes, cleanup and new features. The major changes are:

      -
    • Support for generics in the .Net virtual machine.
    • -
    • Initial support for the Mono class libraries.
    • -
    • Support for MacOSX/x86, following LLVM's support for exceptions in -JIT on MacOSX/x86.
    • -
    • A new vmkit driver: a program to run java or .net applications. The driver -supports llvm command line arguments including the new "-fast" option.
    • -
    • A new memory allocation scheme in the JVM that makes unloading a -class loader very fast.
    • -
    • VMKit now follows the LLVM Makefile machinery.
    • +
    • ...
    + + + +
    +

    +The new LLVM compiler-rt project +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).

    + +

    +All of the code in the compiler-rt project is available under the standard LLVM +License, a "BSD-style" license.

    + +
    + + + + +
    +

    +The new LLVM KLEE project is a symbolic +execution framework for programs in LLVM bitcode form. KLEE tries to +symbolically evaluate "all" paths through the application and records state +transitions that lead to fault states. This allows it to construct testcases +that lead to faults and can even be used to verify algorithms. For more +details, please see the OSDI 2008 paper about +KLEE.

    + +
    + + + + +
    +

    +The goal of DragonEgg is to make +gcc-4.5 act like llvm-gcc without requiring any gcc modifications whatsoever. +DragonEgg is a shared library (dragonegg.so) +that is loaded by gcc at runtime. It ... +

    + +
    + + + + + +
    +

    +The LLVM Machine Code (MC) Toolkit project is ... +

    + +
    + +
    -

    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. +

    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.

    +
    + + + + + +
    +

    Rubinius is an environment +for running Ruby code which strives to write as much of the core class +implementation in Ruby as possible. Combined with a bytecode interpreting VM, it +uses LLVM to optimize and compile ruby code down to machine code. Techniques +such as type feedback, method inlining, and uncommon traps are all used to +remove dynamism from ruby execution and increase performance.

    + +

    Since LLVM 2.5, Rubinius has made several major leaps forward, implementing +a counter based JIT, type feedback and speculative method inlining.

    +
    -

    LLVM 2.4 includes several major new capabilities:

    +

    +MacRuby is an implementation of Ruby on top of +core Mac OS X technologies, such as the Objective-C common runtime and garbage +collector and the CoreFoundation framework. It is principally developed by +Apple and aims at enabling the creation of full-fledged Mac OS X applications. +

    -
      -
    • The most visible end-user change in LLVM 2.4 is that it includes many -optimizations and changes to make -O0 compile times much faster. You should see -improvements in speed on the order of 30% (or more) than in LLVM 2.3. There are -many pieces to this change described in more detail below. The speedups and new -components can also be used for JIT compilers that want fast -compilation.

    • - -
    • The biggest change to the LLVM IR is that Multiple Return Values (which -were introduced in LLVM 2.3) have been generalized to full support for "First -Class Aggregate" values in LLVM 2.4. This means that LLVM IR supports using -structs and arrays as values in a function. This capability is mostly useful -for front-end authors, who prefer to treat things like complex numbers, simple -tuples, dope vectors, etc., as Value*'s instead of as a tuple of Value*'s or as -memory values. Bitcode files from LLVM 2.3 will automatically migrate to the -general representation.

    • - -
    • LLVM 2.4 also includes an initial port for the PIC16 microprocessor. This -target only has support for 8 bit registers, and a number of other crazy -constraints. While the port is still in early development stages, it shows some -interesting things you can do with LLVM.

    • +

      +MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby +expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception +handling.

      -
    +
    + + + +
    +Pure +
    +
    +

    +Pure +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.

    + +

    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). +

    +

    +LDC is an implementation of +the D Programming Language using the LLVM optimizer and code generator. +The LDC project works great with the LLVM 2.6 release. General improvements in +this +cycle have included new inline asm constraint handling, better debug info +support, general bug fixes and better x86-64 support. This has allowed +some major improvements in LDC, getting it much closer to being as +fully featured as the original DMD compiler from DigitalMars. +

    +
    -

    LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC -front-ends and driver with the LLVM optimizer and code generator. It currently -includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.

    + + -
      -
    • LLVM 2.4 supports the full set of atomic __sync_* builtins. LLVM -2.3 only supported those used by OpenMP, but 2.4 supports them all. Note that -while llvm-gcc supports all of these builtins, not all targets do. X86 support -them all in both 32-bit and 64-bit mode and PowerPC supports them all except for -the 64-bit operations when in 32-bit mode.
    • - -
    • llvm-gcc now supports an -flimited-precision option, which tells -the compiler that it is okay to use low-precision approximations of certain libm -functions (like exp, log, etc). This allows you to get high -performance if you only need (say) 12-bits of precision.
    • - -
    • llvm-gcc now supports a C language extension known as "Blocks". -This feature is similar to nested functions and closures, but does not -require stack trampolines (with most ABIs), and supports returning closures -from functions that define them. Note that actually using Blocks -requires a small runtime that is not included with llvm-gcc.
    • - -
    • llvm-gcc now supports a new -flto option. On systems that support -transparent Link Time Optimization (currently Darwin systems with Xcode 3.1 and -later) this allows the use of LTO with other optimization levels like -Os. -Previously, LTO could only be used with -O4, which implied optimizations in --O3 that can increase code size.
    • -
    +
    +

    +Roadsend PHP (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.

    +
    + + + +
    +

    +Unladen Swallow is a +branch of Python intended to be fully +compatible and significantly faster. It uses LLVM's optimization passes and JIT +compiler.

    + + + +
    +

    +LLVM-Lua 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.

    +
    + + + + +
    +

    +IcedTea 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 Shark which uses LLVM +to provide native code generation without introducing processor-dependent +code. +

    +
    + + + + + + + +
    + +

    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. +

    + +
    -

    New features include:

    + +

    LLVM 2.7 includes several major new capabilities:

      -
    • A major change to the Use class landed, which shrank it by 25%. Since -this is a pervasive part of the LLVM, it ended up reducing the memory use of -LLVM IR in general by 15% for most programs.
    • +
    • ...
    • +
    -
  13. Values with no names are now pretty printed by llvm-dis more -nicely. They now print as "%3 = add i32 %A, 4" instead of -"add i32 %A, 4 ; <i32>:3", which makes it much easier to read. -
  14. +
    -
  15. LLVM 2.4 includes some changes for better vector support. First, the shift -operations (shl, ashr, and lshr) now all support -vectors and do an element-by-element shift (shifts of the whole vector can be -accomplished by bitcasting the vector to <1 x i128>, for example). Second, -there is initial support in development for vector comparisons with the -fcmp/icmp -instructions. These instructions compare two vectors and return a vector of -i1's for each result. Note that there is very little codegen support -available for any of these IR features though.
  16. - -
  17. A new DebugInfoBuilder class is available, which makes it much -easier for front-ends to create debug info descriptors, similar to the way that -IRBuilder makes it easier to create LLVM IR.
  18. - -
  19. The IRBuilder class is now parameterized by a class responsible -for constant folding. The default ConstantFolder class does target independent -constant folding. The NoFolder class does no constant folding at all, which is -useful when learning how LLVM works. The TargetFolder class folds the most, -doing target dependent constant folding.
  20. - -
  21. LLVM now supports "function attributes", which allow us to separate return -value attributes from function attributes. LLVM now supports attributes on a -function itself, a return value, and its parameters. New supported function -attributes include noinline/alwaysinline and the opt-size flag, -which says the function should be optimized for code size.
  22. - -
  23. LLVM IR now directly represents "common" linkage, instead of - representing it as a form of weak linkage.
  24. - + + + +
    +

    LLVM IR has several new features for better support of new targets and that +expose new optimization opportunities:

    + +
      +
    • ...
    @@ -338,158 +442,156 @@ which says the function should be optimized for code size.
    -

    In addition to a huge array of bug fixes and minor performance tweaks, this +

    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:

      -
    • The Global Value Numbering (GVN) pass now does local Partial Redundancy -Elimination (PRE) to eliminate some partially redundant expressions in cases -where doing so won't grow code size.
    • - -
    • LLVM 2.4 includes a new loop deletion pass (which removes output-free -provably-finite loops) and a rewritten Aggressive Dead Code Elimination (ADCE) -pass that no longer uses control dependence information. These changes speed up -the optimizer and also prevent it from deleting output-free infinite -loops.
    • +
    • ...
    • -
    • The new AddReadAttrs pass works out which functions are read-only or -read-none (these correspond to 'pure' and 'const' in GCC) and marks them -with the appropriate attribute.
    • +
    -
  25. LLVM 2.4 now includes a new SparsePropagation framework, which makes it -trivial to build lattice-based dataflow solvers that operate over LLVM IR. Using -this interface means that you just define objects to represent your lattice -values and the transfer functions that operate on them. It handles the -mechanics of worklist processing, liveness tracking, handling PHI nodes, -etc.
  26. +
    -
  27. The Loop Strength Reduction and induction variable optimization passes have -several improvements to avoid inserting MAX expressions, to optimize simple -floating point induction variables and to analyze trip counts of more -loops.
  28. -
  29. Various helper functions (ComputeMaskedBits, ComputeNumSignBits, etc) were -pulled out of the Instruction Combining pass and put into a new -ValueTracking.h header, where they can be reused by other passes.
  30. + + -
  31. The tail duplication pass has been removed from the standard optimizer -sequence used by llvm-gcc. This pass still exists, but the benefits it once -provided are now achieved by other passes.
  32. +
    +
      +
    • The JIT now defaults +to compiling eagerly to avoid a race condition in the lazy JIT. +Clients that still want the lazy JIT can switch it on by calling +ExecutionEngine::DisableLazyCompilation(false).
    -

    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:

    +

    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:

      -
    • The target-independent code generator supports (and the X86 backend - currently implements) a new interface for "fast" instruction selection. This - interface is optimized to produce code as quickly as possible, sacrificing - code quality to do it. This is used by default at -O0 or when using - "llc -fast" on X86. It is straight-forward to add support for - other targets if faster -O0 compilation is desired.
    • - -
    • In addition to the new 'fast' instruction selection path, many existing - pieces of the code generator have been optimized in significant ways. - SelectionDAG's are now pool allocated and use better algorithms in many - places, the ".s" file printers now use raw_ostream to emit text much faster, - etc. The end result of these improvements is that the compiler also takes - substantially less time to generate code that is just as good (and often - better) than before.
    • - -
    • Each target has been split to separate the ".s" file printing logic from the - rest of the target. This enables JIT compilers that don't link in the - (somewhat large) code and data tables used for printing a ".s" file.
    • - -
    • The code generator now includes a "stack slot coloring" pass, which packs - together individual spilled values into common stack slots. This reduces - the size of stack frames with many spills, which tends to increase L1 cache - effectiveness.
    • - -
    • Various pieces of the register allocator (e.g. the coalescer and two-address - operation elimination pass) now know how to rematerialize trivial operations - to avoid copies and include several other optimizations.
    • - -
    • The graphs produced by - the llc -view-*-dags options are now significantly prettier and - easier to read.
    • - -
    • LLVM 2.4 includes a new register allocator based on Partitioned Boolean - Quadratic Programming (PBQP). This register allocator is still in - development, but is very simple and clean.
    • +
    • ...
    +
    + + +
    +

    New features of the X86 target include: +

    + +
      + +
    • ...
    • + +
    + +
    -

    New target-specific features include: +

    New features of the PIC16 target include:

      -
    • Exception handling is supported by default on Linux/x86-64.
    • -
    • Position Independent Code (PIC) is now supported on Linux/x86-64.
    • -
    • @llvm.frameaddress now supports getting the frame address of stack frames - > 0 on x86/x86-64.
    • -
    • MIPS has improved a lot since last release, the most important changes - are: Little endian support, floating point support, allegrex core and - intrinsics support. O32 ABI is improved but isn't complete. The EABI - was implemented and is fully supported. We also have support for small - sections and gp_rel relocation for its access, a threshold in bytes can be - specified through command line.
    • -
    • The PowerPC backend now supports trampolines.
    • +
    • ...
    +

    Things not yet supported:

    + +
      +
    • Variable arguments.
    • +
    • Interrupts/programs.
    • +
    + +
    + + + + +
    +

    New features of the ARM target include: +

    + +
      + +
    • ...
    • +
    + + +
    + + + +
    +

    New features of other targets include: +

    + +
      +
    • ...
    • +
    + +
    -

    New features include: + +

    This release includes a number of new APIs that are used internally, which + may also be useful for external clients.

      -
    • llvmc2 (the generic compiler driver) gained plugin - support. It is now easier to experiment with llvmc2 and - build your own tools based on it.
    • - -
    • LLVM 2.4 includes a number of new generic algorithms and data structures, - include a scoped hash table, 'immutable' data structures, a simple - free-list manager, and a raw_ostream class. - The raw_ostream class and - format allow for efficient file output, and various pieces of LLVM - have switched over to use it. The eventual goal is to eliminate - std::ostream in favor of it.
    • - -
    • LLVM 2.4 includes an optional build system based on CMake. It - still is in its early stages but can be useful for Visual C++ - users who can not use the Visual Studio IDE.
    • +
    • ...
    • +
    + + +
    + + + +
    +

    Other miscellaneous features include:

    + +
      +
    • ...
    +
    Major Changes and Removed Features @@ -498,19 +600,11 @@ faster:

    If you're already an LLVM user or developer with out-of-tree changes based -on LLVM 2.3, 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.

      - -
    • The LLVM IR generated by llvm-gcc no longer names all instructions. This - makes it run faster, but may be more confusing to some people. If you - prefer to have names, the 'opt -instnamer' pass will add names to - all instructions.
    • - -
    • The LoadVN and GCSE passes have been removed from the tree. They are - obsolete and have been replaced with the GVN and MemoryDependence passes. -
    • +
    • ...
    @@ -518,51 +612,24 @@ from the previous release.

    API changes are:

      - -
    • Now, function attributes and return value attributes are managed -separately. Interface exported by ParameterAttributes.h header is now -experted by Attributes.h header. The new attributes interface changes are: -
        -
      • getParamAttrs method is now replaced by -getParamAttributes, getRetAttributes and -getFnAttributes methods.
      • -
      • Return value attributes are stored at index 0. Function attributes are -stored at index ~0U. Parameter attributes are stored at index that matches -parameter number.
      • -
      • ParamAttr namespace is now renamed as Attribute.
      • -
      • The name of the class that manages reference count of opaque -attributes is changed from PAListPtr to AttrListPtr.
      • -
      • ParamAttrsWithIndex is now renamed as AttributeWithIndex. -
      • -
      -
    • - -
    • The DbgStopPointInst methods getDirectory and -getFileName now return Value* instead of strings. These can be -converted to strings using llvm::GetConstantStringInfo defined via -"llvm/Analysis/ValueTracking.h".
    • - -
    • The APIs to create various instructions have changed from lower case - "create" methods to upper case "Create" methods (e.g. - BinaryOperator::create). LLVM 2.4 includes both cases, but the - lower case ones are removed in mainline, please migrate.
    • - -
    • Various header files like "llvm/ADT/iterator" were given a ".h" suffix. - Change your code to #include "llvm/ADT/iterator.h" instead.
    • - -
    • The getresult instruction has been removed and replaced with the - extractvalue instruction. This is part of support for first class - aggregates.
    • - -
    • In the code generator, many MachineOperand predicates were renamed to be - shorter (e.g. isFrameIndex() -> isFI()), - SDOperand was renamed to SDValue (and the "Val" - member was changed to be the getNode() accessor), and the - MVT::ValueType enum has been replaced with an "MVT" - struct. The getSignExtended and getValue methods in the - ConstantSDNode class were renamed to getSExtValue and - getZExtValue respectively, to be more consistent with - the ConstantInt class.
    • +
    • ModuleProvider has been removed +and its methods moved to Module and GlobalValue. +Most clients can remove uses of ExistingModuleProvider, +replace getBitcodeModuleProvider with +getLazyBitcodeModule, and pass their Module to +functions that used to accept ModuleProvider. Clients who +wrote their own ModuleProviders will need to derive from +GVMaterializer instead and use +Module::setMaterializer to attach it to a +Module.
    • + +
    • GhostLinkage has given up the ghost. +GlobalValues that have not yet been read from their backing +storage have the same linkage they will have after being read in. +Clients must replace calls to +GlobalValue::hasNotBeenReadFromBitcode with +GlobalValue::isMaterializable.
    @@ -580,16 +647,16 @@ converted to strings using llvm::GetConstantStringInfo defined via

    LLVM is known to work on the following platforms:

      -
    • Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD - (and probably other unix-like systems).
    • -
    • PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and - 64-bit modes.
    • +
    • Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat + Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like + systems).
    • +
    • PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit + and 64-bit modes.
    • Intel and AMD machines running on Win32 using MinGW libraries (native).
    • Intel and AMD machines running on Win32 with the Cygwin libraries (limited support is available for native builds with Visual C++).
    • -
    • Sun UltraSPARC workstations running Solaris 10.
    • +
    • Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.
    • Alpha-based machines running Debian GNU/Linux.
    • -
    • Itanium-based (IA64) machines running Linux and HP-UX.

    The core LLVM infrastructure uses GNU autoconf to adapt itself @@ -607,12 +674,26 @@ portability patches and reports of successful builds or error messages.

    -

    This section contains all known problems with the LLVM system, listed by -component. As new problems are discovered, they will be added to these -sections. If you run into a problem, please check the This section contains significant known problems with the LLVM system, +listed by component. If you run into a problem, please check the LLVM bug database and submit a bug if there isn't already one.

    +
      +
    • The llvm-gcc bootstrap will fail with some versions of binutils (e.g. 2.15) + with a message of "Error: can not do 8 + byte pc-relative relocation" when building C++ code. We intend to + fix this on mainline, but a workaround is to upgrade to binutils 2.17 or + later.
    • + +
    • LLVM will not correctly compile on Solaris and/or OpenSolaris +using the stock GCC 3.x.x series 'out the box', +See: Broken versions of GCC and other tools. +However, A Modern GCC Build +for x86/x86-64 has been made available from the third party AuroraUX Project +that has been meticulously tested for bootstrapping LLVM & Clang.
    • +
    +
    @@ -630,9 +711,11 @@ components, please contact us on the LLVMdev list.

      -
    • The MSIL, IA64, Alpha, SPU, MIPS, and PIC16 backends are experimental.
    • -
    • The llc "-filetype=asm" (the default) is the only supported - value for this option.
    • +
    • The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430 and SystemZ backends are + experimental.
    • +
    • The llc "-filetype=asm" (the default) is the only + supported value for this option. The ELF writer is experimental.
    • +
    • The implementation of Andersen's Alias Analysis has many known bugs.
    @@ -652,13 +735,14 @@ href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list.

  33. The X86 backend generates inefficient floating point code when configured to generate code for systems that don't have SSE2.
  34. Win64 code generation wasn't widely tested. Everything should work, but we - expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime - currently due + expect small issues to happen. Also, llvm-gcc cannot build the mingw64 + runtime currently due to several - bugs due to lack of support for the - 'u' inline assembly constraint and X87 floating point inline assembly.
  35. + bugs and due to lack of support for + the + 'u' inline assembly constraint and for X87 floating point inline assembly.
  36. The X86-64 backend does not yet support the LLVM IR instruction - va_arg. Currently, the llvm-gcc front-end supports variadic + va_arg. Currently, the llvm-gcc and front-ends support variadic argument constructs on X86-64 by lowering them manually.
  37. @@ -686,14 +770,14 @@ compilation, and lacks support for debug information.
      +
    • Support for the Advanced SIMD (Neon) instruction set is still incomplete +and not well tested. Some features may not work at all, and the code quality +may be poor in some cases.
    • Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6 processors, thumb programs can crash or produce wrong results (PR1388).
    • -
    • Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested. +
    • Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
    • -
    • There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly - execute -programs compiled with LLVM. Please use more recent versions of QEMU.
    @@ -706,7 +790,7 @@ programs compiled with LLVM. Please use more recent versions of QEMU.
      -
    • The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not +
    • The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not support the 64-bit SPARC ABI (-m64).
    @@ -720,7 +804,6 @@ programs compiled with LLVM. Please use more recent versions of QEMU.
      -
    • The O32 ABI is not fully supported.
    • 64-bit MIPS targets are not supported yet.
    @@ -741,21 +824,6 @@ appropriate nops inserted to ensure restartability.
    - - - -
    - -
      -
    • The Itanium backend is highly experimental, and has a number of known - issues. We are looking for a maintainer for the Itanium backend. If you - are interested, please contact the LLVMdev mailing list.
    • -
    - -
    -
    Known problems with the C back-end @@ -768,8 +836,9 @@ appropriate nops inserted to ensure restartability. inline assembly code.
  38. The C backend violates the ABI of common C++ programs, preventing intermixing between C++ compiled by the CBE and - C++ code compiled with llc or native compilers.
  39. + C++ code compiled with llc or native compilers.
  40. The C backend does not support all exception handling constructs.
  41. +
  42. The C backend does not support arbitrary precision integers.
  43. @@ -782,10 +851,6 @@ appropriate nops inserted to ensure restartability.
    -

    llvm-gcc does not currently support Link-Time -Optimization on most platforms "out-of-the-box". Please inquire on the -LLVMdev mailing list if you are interested.

    -

    The only major language feature of GCC not supported by llvm-gcc is the __builtin_apply family of builtins. However, some extensions are only supported on some targets. For example, trampolines are only @@ -810,7 +875,7 @@ itself, Qt, Mozilla, etc.

    • Exception handling works well on the X86 and PowerPC targets. Currently - only linux and darwin targets are supported (both 32 and 64 bit).
    • + only Linux and Darwin targets are supported (both 32 and 64 bit).
    @@ -821,12 +886,11 @@ itself, Qt, Mozilla, etc.

    +
    • Fortran support generally works, but there are still several unresolved bugs - in Bugzilla. Please see the tools/gfortran component for details.
    • - -
    • The Fortran front-end currently does not build on Darwin (without tweaks) - due to unresolved dependencies on the C front-end.
    • - + in Bugzilla. Please see the + tools/gfortran component for details. +
    @@ -835,22 +899,26 @@ itself, Qt, Mozilla, etc.

    -The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature -technology and problems should be expected. +The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature +technology, and problems should be expected.
    • 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 also fails to build on X86-64 +to lack of trampoline support (pointers to nested functions) on other platforms. +However, it also fails to build on X86-64 which does support trampolines.
    • The Ada front-end fails to bootstrap. -Workaround: configure with --disable-bootstrap.
    • +This is due to lack of LLVM support for setjmp/longjmp style +exception handling, which is used internally by the compiler. +Workaround: configure with --disable-bootstrap.
    • The c380004, c393010 and cxg2021 ACATS tests fail -(c380004 also fails with gcc-4.2 mainline).
    • -
    • Some gcc specific Ada tests continue to crash the compiler.
    • -
    • The -E binder option (exception backtraces) +(c380004 also fails with gcc-4.2 mainline). +If the compiler is built with checks disabled then c393010 +causes the compiler to go into an infinite loop, using up all system memory.
    • +
    • Some GCC specific Ada tests continue to crash the compiler.
    • +
    • The -E binder option (exception backtraces) does not work and will result in programs -crashing if an exception is raised. Workaround: do not use -E.
    • +crashing if an exception is raised. Workaround: do not use -E.
    • Only discrete types are allowed to start or finish at a non-byte offset in a record. Workaround: do not pack records or use representation clauses that result in a field of a non-discrete type @@ -864,6 +932,20 @@ ignored.
    + + + +
    + +

    The Llvm.Linkage module is broken, and has incorrect values. Only +Llvm.Linkage.External, Llvm.Linkage.Available_externally, and +Llvm.Linkage.Link_once will be correct. If you need any of the other linkage +modes, you'll have to write an external C library in order to expose the +functionality. This has been fixed in the trunk.

    +
    +
    Additional Information @@ -891,9 +973,9 @@ lists.


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