LLVM 1.2 Release Notes
  1. Introduction
  2. What's New?
  3. Portability and Supported Platforms
  4. Installation Instructions
  5. Known Problems
  6. Additional Information

Written by the LLVM team

Introduction

This document contains the release notes for the LLVM compiler infrastructure, release 1.2. 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 1.2 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, this document applies to the next release, not the current one. To see the release notes for the current or previous releases, see the releases page.

What's New?

This is the third public release of the LLVM compiler infrastructure.

At this time, LLVM is known to correctly compile and run all non-unwinding C & C++ SPEC CPU2000 benchmarks, the Olden benchmarks, and the Ptrdist benchmarks. It has also been used to compile many other programs. LLVM now also works with a broad variety of C++ programs, though it has still received much less testing than the C front-end.

The LLVM native code generators are very stable but do not currently support unwinding (exception throwing or longjmping), which prevent them from working with programs like the 253.perlbmk in SPEC CPU2000. The C backend and the rest of LLVM supports these programs, so you can still use LLVM with them. Support for unwinding will be added in a future release.

This release implements the following new features:
In this release, the following missing features were implemented:
  1. Exception handling support in the X86 & Sparc native code generators
In this release, the following Quality of Implementation issues were fixed:
  1. JIT should lazily initialize global variables
  2. [X86] X86 Backend never releases memory for machine code structures
  3. [vmcore] OpaqueType objects memory leak
  4. [llvmgcc] C front-end does not compile "extern inline" into linkonce
  5. Bytecode format inconsistent
  6. [loadvn/inline/scalarrepl] Slow optimizations with extremely large basic blocks
In this release, the following build problems were fixed:
  1. [build] Makefiles break if C frontend target string has unexpected value
  2. [build] hard-wired assumption that shared-library extension is ".so"
  3. make tools-only doesn't make lib/Support
  4. [build] Usage of autoconf is awkward
In this release, the following Code Quality issues were fixed:
  1. [loopsimplify] Many pointless phi nodes are created
  2. The X86 backend didn't generate fchs to negate floating point numbers
In this release, the following bugs in the previous release were fixed:

Bugs in the LLVM Core:

  1. [licm] LICM promotes volatile memory locations to registers
  2. [licm] Memory read after free causes infrequent crash
  3. [indvars] Induction variable canonicalization always makes 32-bit indvars
  4. [constantmerge] Merging globals can cause use of invalid pointers!
  5. [bcreader] Bytecode reader misreads 'long -9223372036854775808'!
  6. VMCore mishandles double -0.0
  7. [X86] X86 backend code generates -0.0 as +0.0
  8. [loopsimplify] Loopsimplify incorrectly updates dominator information

Bugs in the C/C++ front-end:

  1. Need weak linkage on memory management functions in libc runtime to allow them to be overriden
  2. [llvm-gcc] asserts when an extern inline function is redefined
  3. [llvmg++] Dynamically initialized constants cannot be marked 'constant'
  4. [llvmgcc] floating-point unary minus is incorrect for +0.0
  5. [llvm-gcc] miscompilation of 'X = Y = Z' with aggregate values
Portability and Supported Platforms

LLVM has been extensively tested on Intel and AMD machines running Red Hat Linux and FreeBSD. It has also been tested on Sun UltraSPARC workstations running Solaris 8. Additionally, LLVM works on Mac OS X 10.3 and above, but only with the C backend or interpreter (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. If you run into a problem, please check the LLVM bug database and submit a bug if there isn't already one.

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 has not been tested as thoroughly as the C front-end. It has been tested and works for a number of non-trivial programs, but there may be lurking bugs. 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 and 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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