This document contains the release notes for the LLVM compiler -infrastructure, release 2.3. Here we describe the status of LLVM, including -major improvements from the previous release and any known problems. All LLVM -releases may be downloaded from the LLVM -releases web site.
+This document contains the release notes for the LLVM Compiler +Infrastructure, release 2.5. 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 release, please check out the main LLVM web site. If you have questions or comments, the LLVM developer's mailing -list is a good place to send them.
+href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing +List is a good place to send them. -Note that if you are reading this file from a Subversion checkout or the +
Note that if you are reading this file from a Subversion checkout or the main LLVM web page, this document applies to the next release, not the -current one. To see the release notes for a specific releases, please see the +current one. To see the release notes for a specific release, please see the releases page.
+The LLVM 2.5 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. +
+ +This is the fourteenth public release of the LLVM Compiler Infrastructure. -It includes a large number of features and refinements from LLVM 2.2.
+ + - +The Clang project is an effort to build +a set of new 'LLVM native' front-end technologies for the LLVM optimizer and +code generator. While Clang is not included in the LLVM 2.5 release, it is +continuing to make major strides forward in all areas. Its C and Objective-C +parsing and code generation support is now very solid. For example, it is +capable of successfully building many real-world applications for X86-32 +and X86-64, +including the FreeBSD +kernel and gcc 4.2. C++ is also +making incredible progress, +and work on templates has recently started. If you are +interested in fast compiles and good diagnostics, we encourage you to try it out +by building from mainline +and reporting any issues you hit to the Clang front-end mailing +list.
+ +In the LLVM 2.5 time-frame, the Clang team has made many improvements:
+ +-
+
- Clang now has a new driver, which is focused on providing a GCC-compatible + interface. +
- The X86-64 ABI is now supported, including support for the Apple + 64-bit Objective-C runtime and zero cost exception handling. +
- Precompiled header support is now implemented. +
- Objective-C support is significantly improved beyond LLVM 2.4, supporting + many features, such as Objective-C Garbage Collection. +
- Variable length arrays are now fully supported. +
- C99 designated initializers are now fully supported. +
- Clang now includes all major compiler headers, including a + redesigned tgmath.h and several more intrinsic headers. +
- Many many bugs are fixed and many features have been added. +
LLVM 2.3 no longer supports llvm-gcc 4.0, it has been replaced with - llvm-gcc 4.2.
+Previously announced in the last LLVM release, 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.
+ +In the LLVM 2.5 time-frame there have been many significant improvements to +the analyzer's core path simulation engine and machinery for generating +path-based bug reports to end-users. Particularly noteworthy improvements +include experimental support for full field-sensitivity and reasoning about heap +objects as well as an improved value-constraints subengine that does a much +better job of reasoning about inequality relationships (e.g., x > 2) +between variables and constants. + +
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!
+ +LLVM 2.3 no longer includes the llvm-upgrade tool. It was useful - for upgrading LLVM 1.9 files to LLVM 2.x syntax, but you can always use a - previous LLVM release to do this. One nice impact of this is that the LLVM - regression test suite no longer depends on llvm-upgrade, which makes it run - faster.
+ + -The llvm2cpp tool has been folded into llc, use - llc -march=cpp instead of llvm2cpp.
++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.
-LLVM API Changes:
+Following LLVM 2.5, VMKit has its second release that you can find on its +webpage. The release includes +bug fixes, cleanup and new features. The major changes are:
-
-
- Several core LLVM IR classes have migrated to use the - 'FOOCLASS::Create(...)' pattern instead of 'new - FOOCLASS(...)' (e.g. where FOOCLASS=BasicBlock). We hope to - standardize on FOOCLASS::Create for all IR classes in the future, - but not all of them have been moved over yet. -
- LLVM 2.3 renames the LLVMBuilder and LLVMFoldingBuilder classes to - IRBuilder. - -
- MRegisterInfo was renamed to - - TargetRegisterInfo. -
- The MappedFile class is gone, please use - - MemoryBuffer instead. -
- The '-enable-eh' flag to llc has been removed. Now code should - encode whether it is safe to omit unwind information for a function by - tagging the Function object with the 'nounwind' attribute. + +
- Ahead of Time compiler: compiles .class files to llvm .bc. VMKit uses this +functionality to native compile the standard classes (e.g. java.lang.String). +Users can compile AoT .class files into dynamic libraries and run them with the +help of VMKit. + +
- New exception model: the dwarf exception model is very slow for +exception-intensive applications, so the JVM has had a new implementation of +exceptions which check at each function call if an exception happened. There is +a low performance penalty on applications without exceptions, but it is a big +gain for exception-intensive applications. For example the jack benchmark in +Spec JVM98 is 6x faster (performance gain of 83%). + +
- User-level management of thread stacks, so that thread local data access +at runtime is fast and portable. + +
- Implementation of biased locking for faster object synchronizations at +runtime. + +
- New support for OSX/X64, Linux/X64 (with the Boehm GC) and Linux/ppc32.
-The core LLVM 2.3 distribution currently consists of code from the core LLVM -repository (which roughly contains the LLVM optimizer, 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 new vmkit Project -and the Clang Project. +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.
+ +In addition to the usual algebraic data structures, Pure also has +MATLAB-style matrices in order to support numeric computations and signal +processing in an efficient way. Pure is mainly aimed at mathematical +applications right now, but it has been designed as a general purpose language. +The dynamic interpreter environment and the C interface make it possible to use +it as a kind of functional scripting language for many application areas.
-The "vmkit" project is a new addition to the LLVM family. It 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.
- -The JVM, called JnJVM, executes real-world applications such as Apache -projects (e.g. Felix and Tomcat) and the SpecJVM98 benchmark. It uses the GNU -Classpath project for the base classes. The CLI implementation, called N3, is -its in early stages but can execute simple applications and the "pnetmark" -benchmark. It uses the pnetlib project as its core library.
- -The 'vmkit' VMs compare in performance with industrial and top open-source -VMs on scientific applications. Besides the JIT, the VMs use many features of -the LLVM framework, including the standard set of optimizations, atomic -operations, custom function provider and memory manager for JITed methods, and -specific virtual machine optimizations. vmkit is not an official part of LLVM -2.3 release. It is publicly available under the LLVM license and can be -downloaded from: -
- --svn co http://llvm.org/svn/llvm-project/vmkit/trunk vmkit +LDC is an implementation of +the D Programming Language using the LLVM optimizer and code generator. +The LDC project works great with the LLVM 2.5 release. General improvements in +this +cycle have included new inline asm constraint handling, better debug info +support, general bugfixes, and better x86-64 support. This has allowed +some major improvements in LDC, getting us much closer to being as +fully featured as the original DMD compiler from DigitalMars.
-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.
- -At this point, Clang is most useful if you are interested in source-to-source -transformations (such as refactoring) and other source-level tools for C and -Objective-C. Clang now also includes tools for turning C code into pretty HTML, -and includes a new static -analysis tool in development. This tool is automatically focused on finding -bugs in C and Objective-C code.
- +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.
LLVM 2.3 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. +
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.
LLVM 2.3 includes several major new capabilities:
+LLVM 2.5 includes several major new capabilities:
-
-
The biggest change in LLVM 2.3 is Multiple Return Value (MRV) support. - MRVs allow LLVM IR to directly represent functions that return multiple - values without having to pass them "by reference" in the LLVM IR. This - allows a front-end to generate more efficient code, as MRVs are generally - returned in registers if a target supports them. See the LLVM IR Reference for more details.
- -MRVs are fully supported in the LLVM IR, but are not yet fully supported in - on all targets. However, it is generally safe to return up to 2 values from - a function: most targets should be able to handle at least that. MRV - support is a critical requirement for X86-64 ABI support, as X86-64 requires - the ability to return multiple registers from functions, and we use MRVs to - accomplish this in a direct way.
-
-LLVM 2.3 includes a complete reimplementation of the "llvmc" - tool. It is designed to overcome several problems with the original - llvmc and to provide a superset of the features of the - 'gcc' driver.
- -The main features of llvmc2 are: -
-
-
- Extended handling of command line options and smart rules for - dispatching them to different tools. -
- Flexible (and extensible) rules for defining different tools. -
- The different intermediate steps performed by tools are represented - as edges in the abstract graph. -
- The 'language' for driver behavior definition is tablegen and thus - it's relatively easy to add new features. -
- The definition of driver is transformed into set of C++ classes, thus - no runtime interpretation is needed. -
-
-LLVM 2.3 includes a completely rewritten interface for Link Time Optimization. This interface - is written in C, which allows for easier integration with C code bases, and - incorporates improvements we learned about from the first incarnation of the - interface.
-
-The Kaleidoscope tutorial now - includes a "port" of the tutorial that uses the Ocaml bindings to implement - the Kaleidoscope language.
+- LLVM 2.5 includes a brand new XCore backend. + +
- llvm-gcc now generally supports the GFortran front-end, and the precompiled +release binaries now support Fortran, even on Mac OS/X. + +
- CMake is now used by the LLVM build process +on Windows. It automatically generates Visual Studio project files (and +more) from a set of simple text files. This makes it much easier to +maintain. In time, we'd like to standardize on CMake for everything. +
- LLVM 2.5 now uses (and includes) Google Test for unit testing. + +
- The LLVM native code generator now supports arbitrary precision integers. +Types like i33 have long been valid in the LLVM IR, but were previously +only supported by the interpreter. Note that the C backend still does not +support these. + +
- LLVM 2.5 no longer uses 'bison,' so it is easier to build on Windows.
LLVM 2.3 fully supports the llvm-gcc 4.2 front-end, and includes support -for the C, C++, Objective-C, Ada, and Fortran front-ends.
+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-gcc 4.2 includes numerous fixes to better support the Objective-C -front-end. Objective-C now works very well on Mac OS/X. - -
- Fortran EQUIVALENCEs are now supported by the gfortran front-end. - -
- llvm-gcc 4.2 includes many other fixes which improve conformance with the -relevant parts of the GCC testsuite. - -
New features include: -
+LLVM IR has several new features that are used by our existing front-ends and +can be useful if you are writing a front-end for LLVM:
-
-
- LLVM IR now directly represents "common" linkage, instead of representing it -as a form of weak linkage. +
- The shufflevector instruction +has been generalized to allow different shuffle mask width than its input +vectors. This allows you to use shufflevector to combine two +"<4 x float>" vectors into a "<8 x float>" for example. + +
- LLVM IR now supports new intrinsics for computing and acting on overflow of integer operations. This allows +efficient code generation for languages that must trap or throw an exception on +overflow. While these intrinsics work on all targets, they only generate +efficient code on X86 so far. + +
- LLVM IR now supports a new private +linkage type to produce labels that are stripped by the assembler before it +produces a .o file (thus they are invisible to the linker). + +
- LLVM IR supports two new attributes for better alias analysis. The noalias attribute can now be used on the +return value of a function to indicate that it returns new memory (e.g. +'malloc', 'calloc', etc). +The new nocapture attribute can be used +on pointer arguments to indicate that the function does not return the pointer, +store it in an object that outlives the call, or let the value of the pointer +escape from the function in any other way. +Note that it is the pointer itself that must not escape, not the value it +points to: loading a value out of the pointer is perfectly fine. +Many standard library functions (e.g. 'strlen', 'memcpy') have this property. + + + +
- The parser for ".ll" files in lib/AsmParser is now completely rewritten as a +recursive descent parser. This parser produces better error messages (including +caret diagnostics), is less fragile (less likely to crash on strange things), +does not leak memory, is more efficient, and eliminates LLVM's last use of the +'bison' tool. -
- LLVM IR now has support for atomic operations, and this functionality can -be accessed through the llvm-gcc "__sync_synchronize", -"__sync_val_compare_and_swap", and related builtins. Support for atomics are -available in the Alpha, X86, X86-64, and PowerPC backends. +
- Debug information representation and manipulation internals have been + consolidated to use a new set of classes in + llvm/Analysis/DebugInfo.h. These routines are more + efficient, robust, and extensible and replace the older mechanisms. + llvm-gcc, clang, and the code generator now use them to create and process + debug information. -
- The C and Ocaml bindings have extended to cover pass managers, several -transformation passes, iteration over the LLVM IR, target data, and parameter -attribute lists.
In addition to a huge array of bug fixes and minor performance tweaks, the -LLVM 2.3 optimizers support a few major enhancements:
+In addition to a large array of bug fixes and minor performance tweaks, this +release includes a few major enhancements and additions to the optimizers:
-
-
Loop index set splitting on by default. -This transformation hoists conditions from loop bodies and reduces a loop's -iteration space to improve performance. For example,
+- The loop optimizer now improves floating point induction variables in +several ways, including adding shadow induction variables to avoid +"integer <-> floating point" conversions in loops when safe. -
-for (i = LB; i < UB; ++i) - if (i <= NV) - LOOP_BODY -+
is transformed into:
+-NUB = min(NV+1, UB) -for (i = LB; i < NUB; ++i) - LOOP_BODY -- +
We 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 code generator now has support for carrying information about memory - references throughout the entire code generation process, via the - - MachineMemOperand class. In the future this will be used to improve - both pre-pass and post-pass scheduling, and to improve compiler-debugging - output. - -
- The target-independent code generator infrastructure now uses LLVM's - APInt - class to handle integer values, which allows it to support integer types - larger than 64 bits. Note that support for such types is also dependent on - target-specific support. Use of APInt is also a step toward support for - non-power-of-2 integer sizes. - -
- LLVM 2.3 includes several compile time speedups for code with large basic - blocks, particularly in the instruction selection phase, register - allocation, scheduling, and tail merging/jump threading. +
- The Writing an LLVM Compiler +Backend document has been greatly expanded and is substantially more +complete. + +
- The SelectionDAG type legalization logic has been completely rewritten, is +now more powerful (it supports arbitrary precision integer types for example), +and is more correct in several corner cases. The type legalizer converts +operations on types that are not natively supported by the target machine into +equivalent code sequences that only use natively supported types. The old type +legalizer is still available (for now) and will be used if +-disable-legalize-types is passed to the code generator. + -
- Several improvements which make llc's --view-sunit-dags - visualization of scheduling dependency graphs easier to understand. - -
- The code generator allows targets to write patterns that generate subreg - references directly in .td files now. - -
- memcpy lowering in the backend is more aggressive, particularly for - memcpy calls introduced by the code generator when handling - pass-by-value structure argument copies. +
- The code generator now supports widening illegal vectors to larger legal +ones (for example, converting operations on <3 x float> to work on +<4 x float>) which is very important for common graphics +applications. + +
- The assembly printers for each target are now split out into their own +libraries that are separate from the main code generation logic. This reduces +the code size of JIT compilers by not requiring them to be linked in. + +
- The 'fast' instruction selection path (used at -O0 and for fast JIT + compilers) now supports accelerating codegen for code that uses exception + handling constructs. -
- Inline assembly with multiple register results now returns those results - directly in the appropriate registers, rather than going through memory. - Inline assembly that uses constraints like "ir" with immediates now use the - 'i' form when possible instead of always loading the value in a register. - This saves an instruction and reduces register use. - -
- Added support for PIC/GOT style tail calls on x86/32 and initial support - for tail calls on PowerPC 32 (it may also work on ppc64 but not - thoroughly tested). +
- The optional PBQP register allocator now supports register coalescing.
New features of the X86 target include: +
+ +-
+
- The llvm.returnaddress +intrinsic (which is used to implement __builtin_return_address) now +supports non-zero stack depths on X86. + +
- The X86 backend now supports code generation of vector shift operations +using SSE instructions. + +
- X86-64 code generation now takes advantage of red zone, unless the +-mno-red-zone option is specified. + +
- The X86 backend now supports using address space #256 in LLVM IR as a way of +performing memory references off the GS segment register. This allows a +front-end to take advantage of very low-level programming techniques when +targeting X86 CPUs. See test/CodeGen/X86/movgs.ll for a simple +example. + +
- The X86 backend now supports a -disable-mmx command line option to + prevent use of MMX even on chips that support it. This is important for cases + where code does not contain the proper llvm.x86.mmx.emms + intrinsics. + +
- The X86 JIT now detects the new Intel Core i7 and Atom chips and + auto-configures itself appropriately for the features of these chips. + +
- The JIT now supports exception handling constructs on Linux/X86-64 and + Darwin/x86-64. + +
- The JIT supports Thread Local Storage (TLS) on Linux/X86-32 but not yet on + X86-64. +
New target-specific features include: +
New features of the PIC16 target include:
-
-
- llvm-gcc's X86-64 ABI conformance is far improved, particularly in the - area of passing and returning structures by value. llvm-gcc compiled code - now interoperates very well on X86-64 systems with other compilers. +
- Both direct and indirect load/stores work now. +
- Logical, bitwise and conditional operations now work for integer data +types. +
- Function calls involving basic types work now. +
- Support for integer arrays. +
- The compiler can now emit libcalls for operations not supported by m/c +instructions. +
- Support for both data and ROM address spaces. +
Things not yet supported:
+ +-
+
- Floating point. +
- Passing/returning aggregate types to and from functions. +
- Variable arguments. +
- Indirect function calls. +
- Interrupts/programs. +
- Debug info. +
New features include:
--
+
- Beginning with LLVM 2.5, llvmc2 is known as + just llvmc. The old llvmc driver was removed. -
- The X86 backend now does a number of optimizations that aim to avoid - converting numbers back and forth from SSE registers to the X87 floating - point stack. +
- The Clang plugin was substantially improved and is now enabled + by default. The command llvmc --clang can be now used as a + synonym to ccc. -
- The X86 backend supports stack realignment, which is particularly useful for - vector code on OS's without 16-byte aligned stacks. +
- There is now a --check-graph option, which is supposed to catch + common errors like multiple default edges, mismatched output/input language + names and cycles. In general, these checks can't be done at compile-time + because of the need to support plugins. -
- The X86 backend now supports the "sseregparm" options in GCC, which allow - functions to be tagged as passing floating point values in SSE - registers. +
- Plugins are now more flexible and can refer to compilation graph nodes and + options defined in other plugins. To manage dependencies, a priority-sorting + mechanism was introduced. This change affects the TableGen file syntax. See the + documentation for details. -
- Trampolines (taking the address of a nested function) now work on - Linux/X86-64. +
- Hooks can now be provided with arguments. The syntax is "$CALL(MyHook, + 'Arg1', 'Arg2', 'Arg3')". -
- __builtin_prefetch is now compiled into the appropriate prefetch - instructions instead of being ignored. +
- A new option type: multi-valued option, for options that take more than one + argument (for example, "-foo a b c"). -
- 128-bit integers are now supported on X86-64 targets. +
- New option properties: 'one_or_more', 'zero_or_more', +'hidden' and 'really_hidden'. -
- The register allocator can now rematerialize PIC-base computations. +
- The 'case' expression gained an 'error' action and + an 'empty' test (equivalent to "(not (not_empty ...))"). -
- The "t" and "f" inline assembly constraints for the X87 floating point stack - now work. However, the "u" constraint is still not fully supported. +
- Documentation now looks more consistent to the rest of the LLVM + docs. There is also a man page now.
New target-specific features include: -
+ +If you're already an LLVM user or developer with out-of-tree changes based +on LLVM 2.4, this section lists some "gotchas" that you may run into upgrading +from the previous release.
-
-
- The LLVM C backend now supports vector code. -
New features include: -
+In addition, many APIs have changed in this release. Some of the major LLVM +API changes are:
-
-
- LLVM now builds with GCC 4.3. -
- Bugpoint now supports running custom scripts (with the -run-custom - option) to determine how to execute the command and whether it is making - forward process. +
- Some deprecated interfaces to create Instruction subclasses, that + were spelled with lower case "create," have been removed.
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 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 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++). @@ -557,9 +665,8 @@ portability patches and reports of successful builds or error messages.
- The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental. -
- The llc "-filetype=asm" (the default) is the only supported - value for this option. +
- 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 X86 backend generates inefficient floating point code when configured to generate code for systems that don't have SSE2.
- 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 in FP stackifier -
- The X86-64 backend does not yet support position-independent code (PIC) - generation on Linux targets. + bugs and due to lack of support for + the + 'u' inline assembly constraint and for X87 floating point inline assembly.
- 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.
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.
@@ -580,9 +687,9 @@ components, please contact us on the LLVMdev list.-
-
-
-
- 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).
-
+
- The O32 ABI is not fully supported. +
- 64-bit MIPS targets are not supported yet. +
-
-
-
- C++ programs are likely to fail on IA64, as calls to setjmp are -made where the argument is not 16-byte aligned, as required on IA64. (Strictly -speaking this is not a bug in the IA64 back-end; it will also be encountered -when building C++ programs using the C back-end.) - -
- The C++ front-end does not use IA64 -ABI compliant layout of v-tables. In particular, it just stores function -pointers instead of function descriptors in the vtable. This bug prevents -mixing C++ code compiled with LLVM with C++ objects compiled by other C++ -compilers. - -
- There are a few ABI violations which will lead to problems when mixing LLVM -output with code built with other compilers, particularly for floating-point -programs. - -
- Defining vararg functions is not supported (but calling them is OK). - -
- The Itanium backend has bitrotted somewhat. +
- 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.
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.
+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 @@ -765,13 +868,23 @@ tested and works for a number of non-trivial programs, including LLVM itself, Qt, Mozilla, etc.
-
-
- Exception handling works well on the X86 and PowerPC targets, including -X86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is -supported on X86-64 linux, but that is disabled by default in this release. +
- Exception handling works well on the X86 and PowerPC targets. Currently + only Linux and Darwin targets are supported (both 32 and 64 bit).
-
+
- Fortran support generally works, but there are still several unresolved bugs + in Bugzilla. Please see the tools/gfortran component for details. +
- 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. +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 and c393010 ACATS tests -fail (c380004 also fails with gcc-4.2 mainline). When built at -O3, the -cxg2021 ACATS test also fails. -
- Some gcc specific Ada tests continue to crash the compiler. The testsuite -reports most tests as having failed even though they pass. +
- The c380004, c393010 +and cxg2021 ACATS tests fail +(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. @@ -836,9 +952,9 @@ lists.
+ src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS">
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