From 21e1b7a13c0b1201b51304c9801a66a9f7dd7871 Mon Sep 17 00:00:00 2001
From: Chris Lattner Written by the LLVM Team This document contains the release notes for the LLVM Compiler
- Infrastructure, release 3.0. Here we describe the status of LLVM, including
+ Infrastructure, release 3.1. Here we describe the status of LLVM, including
major improvements from the previous release, improvements in various
subprojects of LLVM, and some of the current users of the code.
All LLVM releases may be downloaded from
@@ -74,7 +72,7 @@ Release Notes.
The LLVM 3.0 distribution currently consists of code from the core LLVM
+ The LLVM 3.1 distribution currently consists of code from the core LLVM
repository (which roughly includes the LLVM optimizers, code generators and
supporting tools), and the Clang repository. In
addition to this code, the LLVM Project includes other sub-projects that are
@@ -96,49 +94,12 @@ Release Notes.
production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
(32- and 64-bit), and for Darwin/ARM targets. In the LLVM 3.0 time-frame, the Clang team has made many improvements: In the LLVM 3.1 time-frame, the Clang team has made many improvements: For more details about the changes to Clang since the 2.9 release, see the
+
+ For more details about the changes to Clang since the 2.9 release, see the
Clang release notes
The 3.0 release has the following notable changes: The 3.1 release has the following notable changes: In the LLVM 3.0 timeframe, the target specific ARM code has converted to
- "unified" assembly syntax, and several new functions have been added to the
- library. .... LLDB has advanced by leaps and bounds in the 3.0 timeframe. It is
- dramatically more stable and useful, and includes both a
- new tutorial and
- a side-by-side comparison with
- GDB. ...LLVM 3.0 Release Notes
+LLVM 3.1 Release Notes
@@ -46,7 +44,7 @@ Release Notes.
-
-
-
-
- Some new Objective-C features require either the Mac OS X 10.7 / iOS 5
- Objective-C runtime, or version 1.6 or later of the GNUstep Objective-C
- runtime version.
-
@@ -203,9 +151,7 @@ Release Notes.
implementations of this and other low-level routines (some are 3x faster than
the equivalent libgcc routines).
-
Libc++ has been ported to FreeBSD and imported into the base system. It is - planned to be the default STL implementation for FreeBSD 10.
+...
@@ -256,71 +197,20 @@ Release Notes. implementation of a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and just-in-time compilation. -In the LLVM 3.0 time-frame, VMKit has had significant improvements on both +
In the LLVM 3.1 time-frame, VMKit has had significant improvements on both runtime and startup performance:
- LLBrowse is an interactive viewer for LLVM modules. It can load any LLVM - module and displays its contents as an expandable tree view, facilitating an - easy way to inspect types, functions, global variables, or metadata nodes. It - is fully cross-platform, being based on the popular wxWidgets GUI - toolkit.
- -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 3.0.
- - -AddressSanitizer - uses compiler instrumentation and a specialized malloc library to find C/C++ - bugs such as use-after-free and out-of-bound accesses to heap, stack, and - globals. The key feature of the tool is speed: the average slowdown - introduced by AddressSanitizer is less than 2x.
- -Clam AntiVirus is an open source (GPL) - anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail - gateways.
- -Since version 0.96 it - has bytecode - signatures that allow writing detections for complex malware. - It uses LLVM's JIT to speed up the execution of bytecode on X86, X86-64, - PPC32/64, falling back to its own interpreter otherwise. The git version was - updated to work with LLVM 3.0.
- -clang_complete is a - VIM plugin, that provides accurate C/C++ autocompletion using the clang front - end. The development version of clang complete, can directly use libclang - which can maintain a cache to speed up auto completion.
- -clReflect is a C++ - parser that uses clang/LLVM to derive a light-weight reflection database - suitable for use in game development. It comes with a very simple runtime - library for loading and querying the database, requiring no external - dependencies (including CRT), and an additional utility library for object - management and serialisation.
- -Cling is an interactive compiler interface - (aka C++ interpreter). It supports C++ and C, and uses LLVM's JIT and the - Clang parser. It has a prompt interface, runs source files, calls into shared - libraries, prints the value of expressions, even does runtime lookup of - identifiers (dynamic scopes). And it just behaves like one would expect from - an interpreter.
- -Crack aims to provide - the ease of development of a scripting language with the performance of a - compiled language. The language derives concepts from C++, Java and Python, - incorporating object-oriented programming, operator overloading and strong - typing.
- -Eero is a fully - header-and-binary-compatible dialect of Objective-C 2.0, implemented with a - patched version of the Clang/LLVM compiler. It features a streamlined syntax, - Python-like indentation, and new operators, for improved readability and - reduced code clutter. It also has new features such as limited forms of - operator overloading and namespaces, and strict (type-and-operator-safe) - enumerations. It is inspired by languages such as Smalltalk, Python, and - Ruby.
- -FAUST is a compiled language for - real-time audio signal processing. The name FAUST stands for Functional - AUdio STream. Its programming model combines two approaches: functional - programming and block diagram composition. In addition with the C, C++, Java - output formats, the Faust compiler can now generate LLVM bitcode, and works - with LLVM 2.7-3.0. -
- -GHC 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.
- -GHC 7.0 and onwards include an LLVM code generator, supporting LLVM 2.8 and - later. Since LLVM 2.9, GHC now includes experimental support for the ARM - platform with LLVM 3.0.
- -gwXscript is an object oriented, - aspect oriented programming language which can create both executables (ELF, - EXE) and shared libraries (DLL, SO, DYNLIB). The compiler is implemented in - its own language and translates scripts into LLVM-IR which can be optimized - and translated into native code by the LLVM framework. Source code in - gwScript contains definitions that expand the namespaces. So you can build - your project and simply 'plug out' features by removing a file. The remaining - project does not leave scars since you directly separate concerns by the - 'template' feature of gwX. It is also possible to add new features to a - project by just adding files and without editing the original project. This - language is used for example to create games or content management systems - that should be extendable.
- -gwXscript is strongly typed and offers comfort with its native types string, - hash and array. You can easily write new libraries in gwXscript or native - code. gwXscript is type safe and users should not be able to crash your - program or execute malicious code except code that is eating CPU time.
- -include-what-you-use
- is a tool to ensure that a file directly #include
s
- all .h
files that provide a symbol that the file uses. It also
- removes superfluous #include
s from source files.
ispc is a compiler for "single program, - multiple data" (SPMD) programs. It compiles a C-based SPMD programming - language to run on the SIMD units of CPUs; it often delivers 5-6x speedups on - a single core of a CPU with an 8-wide SIMD unit compared to serial code, - while still providing a clean and easy-to-understand programming model. For - an introduction to the language and its performance, - see the walkthrough of a short - example program. ispc is licensed under the BSD license.
- -Julia is a high-level, - high-performance dynamic language for technical - computing. It provides a sophisticated compiler, distributed parallel - execution, numerical accuracy, and an extensive mathematical function - library. The compiler uses type inference to generate fast code - without any type declarations, and uses LLVM's optimization passes and - JIT compiler. The language is designed around multiple dispatch, - giving programs a large degree of flexibility. It is ready for use on many - kinds of problems.
-LanguageKit is - a framework for implementing dynamic languages sharing an object model with - Objective-C. It provides static and JIT compilation using LLVM along with - its own interpreter. Pragmatic Smalltalk is a dialect of Smalltalk, built on - top of LanguageKit, that interfaces directly with Objective-C, sharing the - same object representation and message sending behaviour. These projects are - developed as part of the Étoilé desktop environment.
- -LuaAV is a real-time - audiovisual scripting environment based around the Lua language and a - collection of libraries for sound, graphics, and other media protocols. LuaAV - uses LLVM and Clang to JIT compile efficient user-defined audio synthesis - routines specified in a declarative syntax.
- -An open source, cross-platform implementation of C# and the CLR that is - binary compatible with Microsoft.NET. Has an optional, dynamically-loaded - LLVM code generation backend in Mini, the JIT compiler.
- -Note that we use a Git mirror of LLVM with some patches.
- -Polly is an advanced data-locality - optimizer and automatic parallelizer. It uses an advanced, mathematical - model to calculate detailed data dependency information which it uses to - optimize the loop structure of a program. Polly can speed up sequential code - by improving memory locality and consequently the cache use. Furthermore, - Polly is able to expose different kind of parallelism which it exploits by - introducing (basic) OpenMP and SIMD code. A mid-term goal of Polly is to - automatically create optimized GPU code.
- -Portable OpenCL is an open source implementation of the OpenCL standard which - can be easily adapted for new targets. One of the goals of the project is - improving performance portability of OpenCL programs, avoiding the need for - target-dependent manual optimizations. A "native" target is included, which - allows running OpenCL kernels on the host (CPU).
- -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. The interpreter uses LLVM as a backend to JIT-compile Pure - programs to fast native code. 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 interface to C and other programming - languages (including the ability to load LLVM bitcode modules, and inline C, - C++, Fortran and Faust code in Pure programs if the corresponding LLVM-enabled - compilers are installed).
- -Pure version 0.48 has been tested and is known to work with LLVM 3.0 - (and continues to work with older LLVM releases >= 2.5).
- -Renderscript - is Android's advanced 3D graphics rendering and compute API. It provides a - portable C99-based language with extensions to facilitate common use cases - for enhancing graphics and thread level parallelism. The Renderscript - compiler frontend is based on Clang/LLVM. It emits a portable bitcode format - for the actual compiled script code, as well as reflects a Java interface for - developers to control the execution of the compiled bitcode. Executable - machine code is then generated from this bitcode by an LLVM backend on the - device. Renderscript is thus able to provide a mechanism by which Android - developers can improve performance of their applications while retaining - portability.
- -SAFECode is a memory safe C/C++ - compiler built using LLVM. It takes standard, unannotated C/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. SAFECode can be used as a debugging aid - (like Valgrind) to find and repair memory safety bugs. It can also be used - to protect code from security attacks at run-time.
- -The Stupid D Compiler is a - project seeking to write a self-hosting compiler for the D programming - language without using the frontend of the reference compiler (DMD).
- -TCE 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.
- -TCE uses 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.
- -Tart is a general-purpose, - strongly typed programming language designed for application - developers. Strongly inspired by Python and C#, Tart focuses on practical - solutions for the professional software developer, while avoiding the clutter - and boilerplate of legacy languages like Java and C++. Although Tart is still - in development, the current implementation supports many features expected of - a modern programming language, such as garbage collection, powerful - bidirectional type inference, a greatly simplified syntax for template - metaprogramming, closures and function literals, reflection, operator - overloading, explicit mutability and immutability, and much more. Tart is - flexible enough to accommodate a broad range of programming styles and - philosophies, while maintaining a strong commitment to simplicity, minimalism - and elegance in design.
- -ThreadSanitizer is a - data race detector for (mostly) C and C++ code, available for Linux, Mac OS - and Windows. On different systems, we use binary instrumentation frameworks - (Valgrind and Pin) as frontends that generate the program events for the race - detection algorithm. On Linux, there's an option of using LLVM-based - compile-time instrumentation.
- -LLVM 3.0 includes several major changes and big features:
+LLVM 3.1 includes several major changes and big features:
__builtin_expect
from GNU C).__builtin_expect
calls. That information is currently used for
- register spill placement and if-conversion, with additional optimizations
- planned for future releases. The same framework is intended for eventual
- use with profile-guided optimization.getExecutionDomain
and setExecutionDomain
hooks
- to use the pass.New features and major changes in the X86 target include:
-mavx
to the compiler. AVX2 implementation is
- underway on mainline.@llvm.x86.sse42.crc32.[8|16|32]
- and @llvm.x86.sse42.crc64.[8|64]
. They have been renamed to
- @llvm.x86.sse42.crc32.32.[8|16|32]
and
- @llvm.x86.sse42.crc32.64.[8|64]
.New features of the ARM target include:
- The PTX back-end is still experimental, but is fairly usable for compute kernels - in LLVM 3.0. Most scalar arithmetic is implemented, as well as intrinsics to - access the special PTX registers and sync instructions. The major missing - pieces are texture/sampler support and some vector operations.
- -That said, the backend is already being used for domain-specific languages - and can be used by Clang to - compile OpenCL - C code into PTX.
- --mcpu=mblaze3
- and the 5-stage pipeline model can be selected with
- -mcpu=mblaze5
.If you're already an LLVM user or developer with out-of-tree changes based on - LLVM 2.9, this section lists some "gotchas" that you may run into upgrading + LLVM 3.1, this section lists some "gotchas" that you may run into upgrading from the previous release.
LLVMC
meta compiler driver was removed.TailDup
pass was not used in the standard pipeline
- and was unable to update ssa form, so it has been removed.
- load volatile
"/"store volatile
". The old
- syntax ("volatile load
"/"volatile store
")
- is still accepted, but is now considered deprecated and will be removed in
- 3.1.llvm.memory.barrier
and
- llvm.atomic.*
) are now gone. Please use the new atomic
- instructions, described in the atomics guide.
- PATypeHolder
and OpaqueType
are gone,
- and all APIs deal with Type*
instead of const
- Type*
. If you need to create recursive structures, then create a
- named structure, and use setBody()
when all its elements are
- built. Type merging and refining is gone too: named structures are not
- merged with other structures, even if their layout is identical. (of
- course anonymous structures are still uniqued by layout).PHINode::reserveOperandSpace
has been removed. Instead, you
- must specify how many operands to reserve space for when you create the
- PHINode, by passing an extra argument
- into PHINode::Create
.PHINode::block_begin
- and PHINode::block_end
.ArrayRef
instead of either a
- pair of pointers (or iterators) to the beginning and end of a range, or a
- pointer and a length. Others now return an ArrayRef
instead
- of a reference to a SmallVector
- or std::vector
. These include:
-CallInst::Create
ComputeLinearIndex
(in llvm/CodeGen/Analysis.h
)ConstantArray::get
ConstantExpr::getExtractElement
ConstantExpr::getGetElementPtr
ConstantExpr::getInBoundsGetElementPtr
ConstantExpr::getIndices
ConstantExpr::getInsertElement
ConstantExpr::getWithOperands
ConstantFoldCall
(in llvm/Analysis/ConstantFolding.h
)ConstantFoldInstOperands
(in llvm/Analysis/ConstantFolding.h
)ConstantVector::get
DIBuilder::createComplexVariable
DIBuilder::getOrCreateArray
ExtractValueInst::Create
ExtractValueInst::getIndexedType
ExtractValueInst::getIndices
FindInsertedValue
(in llvm/Analysis/ValueTracking.h
)gep_type_begin
(in llvm/Support/GetElementPtrTypeIterator.h
)gep_type_end
(in llvm/Support/GetElementPtrTypeIterator.h
)GetElementPtrInst::Create
GetElementPtrInst::CreateInBounds
GetElementPtrInst::getIndexedType
InsertValueInst::Create
InsertValueInst::getIndices
InvokeInst::Create
IRBuilder::CreateCall
IRBuilder::CreateExtractValue
IRBuilder::CreateGEP
IRBuilder::CreateInBoundsGEP
IRBuilder::CreateInsertValue
IRBuilder::CreateInvoke
MDNode::get
MDNode::getIfExists
MDNode::getTemporary
MDNode::getWhenValsUnresolved
SimplifyGEPInst
(in llvm/Analysis/InstructionSimplify.h
)TargetData::getIndexedOffset
StringMap::getOrCreateValue
have been remove
- except for the one which takes a StringRef
.LLVMBuildUnwind
function from the C API was removed. The
- LLVM unwind
instruction has been deprecated for a long time
- and isn't used by the current front-ends. So this was removed during the
- exception handling rewrite.LLVMAddLowerSetJmpPass
function from the C API was
- removed because the LowerSetJmp
pass was removed.DIBuilder
interface used by front ends to encode
- debugging information in the LLVM IR now expects clients to
- use DIBuilder::finalize()
at the end of translation unit to
- complete debugging information encoding.llvm.memset.i32
).INITIALIZE_PASS{BEGIN,END,}
- and INITIALIZE_{PASS,AG}_DEPENDENCY
.