LLVM 1.1 Release Notes
  1. Introduction
  2. What's New?
  3. Portability and Supported Platforms
  4. Installation Instructions
  5. Known Problems
  6. Additional Information

Written by Chris Lattner

Introduction

This document contains the release notes for the LLVM compiler infrastructure, release 1.1. Here we describe the status of LLVM, including any known problems, and bug fixes from the previous release. The most up-to-date version of this document can be found on the LLVM 1.1 web site. If you are not reading this on the LLVM web pages, you should probably go there, because this document may be updated after the release.

For more information about LLVM, including information about potentially more current releases, please check out the main web site. If you have questions or comments, the LLVM developer's mailing list is a good place to send them.

Note that if you are reading this file from CVS, that this document applies to the next release, not the previous one. To see the release notes for the previous release, see the releases page.

What's New?

This is the second public release of the LLVM compiler infrastructure. This release implements the following new features:

  1. A new LLVM profiler, similar to gprof is available
  2. LLVM and the C/C++ front-end now compile on Mac OSX! Mac OSX users can now explore the LLVM optimizer with the C backend (note that LLVM requires GCC 3.3 on Mac OSX).
  3. LLVM has been moved into an 'llvm' C++ namespace, for easier integration with third-party code. Note that due to a bug in GDB 5.x, to debug namespacified LLVM code, you will need to upgrade to GDB 6.
  4. The build system now copies Makefiles dynamically from the source tree to the object tree as subdirectories are built. This means that:
    1. New directories can be added to the source tree, and the build will automatically pick them up (i.e. no need to re-run configure).
    2. You will need to build LLVM from the top of the object tree once to ensure that all of the Makefiles are copied into the object tree subdirectories.
  5. The configure script will now configure all projects placed in the llvm/projects directory.

In this release, the following missing features were implemented:

  1. The interpreter does not support invoke or unwind
  2. Interpreter does not support the vaarg instruction
  3. llvm-nm cannot read archive files

In this release, the following Quality of Implementation issues were fixed:

  1. C++ front-end is not generating linkonce linkage type when it can
  2. C front-end doesn't emit getelementptr for address of array element
  3. Bad path to the C/C++ frontend causes build problems
  4. LLVM header files should be -Wold-style-cast clean
  5. The LLVM bytecode reader has been sped up a lot (up to 4x in some cases).
  6. Methods and functions in anonymous namespaces now get internal linkage.
  7. Constant initializers now generate loops instead of potentially huge amounts of straight-line code.
  8. Code for running C++ destructors is now properly shared when possible. Before, the C++ front-end generated N^2 amounts of duplicated cleanup code in some cases.

In this release, the following bugs in the previous release were fixed:

  1. [inliner] Inlining invoke with PHI in unwind target is broken
  2. [linker] linkonce globals should link successfully to external globals
  3. C++ frontend can crash when compiling virtual base classes
  4. C backend fails on constant cast expr to ptr-to-anonymous struct
  5. #ident is not recognized by C frontend
  6. [constmerge] Constant merging pass merges constants with external linkage
  7. C front-end miscompiles the builtin_expect intrinsic!
  8. [scalarrepl] Scalar Replacement of aggregates is decimating structures it shouldn't be
  9. 1.0 precompiled libstdc++ does not include wchar_t support
  10. llvmgcc asserts when compiling functions renamed with asm's
  11. C frontend crashes on some programs with lots of types.
  12. [instcombine] Resolving invoke inserts cast after terminator
  13. llvm-as crashes when labels are used in phi nodes
  14. [build problem] Callgraph.cpp not pulled in from libipa.a
  15. Variables in scope of output setjmp calls should be volatile. Note that this does not effect correctness on many platforms, such as X86.
  16. llvm-gcc crashes compiling global union initializer
  17. C front-end crash on empty structure
  18. CFrontend crashes when compiling C99 compound expressions
  19. [X86] Emission of global bool initializers broken
  20. llvm-gcc infinite loops on "case MAXINT:"
  21. [C++] Catch blocks make unparsable labels
  22. [C++] Initializing array with constructable objects fail
  23. [gccld] The -r (relinking) option does not work correctly
  24. [bcreader] Cannot read shift constant expressions from bytecode file
  25. [lowersetjmp] Lowersetjmp pass breaks dominance properties!
  26. llvm-gcc tries to add bools
  27. SymbolTable::getUniqueName is very inefficient
  28. [buildscripts] Building into objdir with .o in it fails
  29. [setjmp/longjmp] Linking C programs which use setjmp/longjmp sometimes fail with references to the C++ runtime library!
  30. [c++] C++ Frontend lays out superclasses like anonymous bitfields!
  31. AsmParser Misses Symbol Redefinition Error
  32. gccld -Lfoo -lfoo fails to find ./foo/libfoo.a
  33. [bcreader] Incorrect cast causes misread forward constant references
  34. Casting a string constant to void crashes llvm-gcc
  35. [adce] ADCE considers blocks without postdominators to be unreachable
  36. C front-end miscompiles unsigned enums whose LLVM types are signed
  37. [X86] div and rem constant exprs invalidate iterators!
  38. [llvmg++] Enum types are incorrectly shrunk to smaller than 'int' size
  39. [llvmg++] Cannot use pointer to member to initialize global
  40. [vmcore] Symbol table doesn't rename colliding variables during type resolution
  41. [llvm-gcc] ?: operator as lvalue not implemented
  42. [C/C++] Bogus warning about taking the address of 'register' variable
  43. bugpoint must not pass -R<directory> to Mach-O linker
  44. crash assigning into an array in a struct which contains a bitfield.
  45. Oversized integer bitfields cause crash
  46. gccld produces a runner script that includes command-line options to load the necessary shared objects
  47. [llvm-gcc] Bitfields & large array don't mix well
  48. [llvm-gcc] Complex division is not supported
  49. [llvm-gcc] Illegal union field reference
  50. [llvmg++] Front-end attempts to return structure by value
  51. [llvmg++] Pointer to member initializers not supported in constructors
  52. [llvm-gcc] crash on union initialization
  53. [llvm-g++] ?: expressions do not run correct number of destructors!
  54. [llvm-gcc] Pointer & constant results in invalid shift

At this time, LLVM is known to work properly with SPEC CPU 2000 (X86 only), the Olden benchmarks, and the Ptrdist benchmarks among many other programs. Note however that the Sparc and X86 backends do not currently support exception throwing or long jumping (including 253.perlbmk in SPEC). For these programs, you must use the C backend.

Portability and Supported Platforms

LLVM has been extensively tested on Intel and AMD machines running Red Hat Linux, and Sun UltraSPARC workstations running Solaris 8. Additionally, LLVM works on Mac OS/X 10.3 and above, but only with the C back-end (no native backend for the PowerPC is available yet). The core LLVM infrastructure uses "autoconf" for portability, so hopefully we work on more platforms than that. However, it is likely that we missed something, and that minor porting is required to get LLVM to work on new platforms. We welcome portability patches and error messages.

Known Problems

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.

Known problems with the LLVM Core
Known problems with the C front-end
Bugs
Notes

If you run into GCC extensions which have not been included in any of these lists, please let us know (also including whether or not they work).

Known problems with the C++ front-end

For this release, the C++ front-end is considered to be fully functional but of beta quality. It has been tested and works for a number of simple programs that collectively exercise most of the language. Nevertheless, it has not been in use as long as the C front-end. Please report any bugs or problems.

Bugs
Notes
Known problems with the X86 back-end
Known problems with the Sparc back-end
Known problems with the C back-end
Additional Information

A wide variety of additional information is available on the LLVM web page, including mailing lists publications describing algorithms and components implemented in LLVM. The web page also contains versions of the API documentation which is up-to-date with the CVS version of the source code. You can access versions of these documents specific to this release by going into the "llvm/doc/" directory in the LLVM tree.

If you have any questions or comments about LLVM, please feel free to contact us via the mailing lists.


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