:local:
.. warning::
- These are in-progress notes for the upcoming LLVM 3.5 release. You may
- prefer the `LLVM 3.4 Release Notes <http://llvm.org/releases/3.4/docs
+ These are in-progress notes for the upcoming LLVM 3.6 release. You may
+ prefer the `LLVM 3.5 Release Notes <http://llvm.org/releases/3.5.0/docs
/ReleaseNotes.html>`_.
============
This document contains the release notes for the LLVM Compiler Infrastructure,
-release 3.5. Here we describe the status of LLVM, including major improvements
+release 3.6. 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 the `LLVM releases web site <http://llvm.org/releases/>`_.
Non-comprehensive list of changes in this release
=================================================
-* All backends have been changed to use the MC asm printer and support for the
- non MC one has been removed.
-
-* Clang can now successfully self-host itself on Linux/Sparc64 and on
- FreeBSD/Sparc64.
-
-* LLVM now assumes the assembler supports ``.loc`` for generating debug line
- numbers. The old support for printing the debug line info directly was only
- used by ``llc`` and has been removed.
-
-* All inline assembly is parsed by the integrated assembler when it is enabled.
- Previously this was only the case for object-file output. It is now the case
- for assembly output as well. The integrated assembler can be disabled with
- the ``-no-integrated-as`` option,
-
-* llvm-ar now handles IR files like regular object files. In particular, a
- regular symbol table is created for symbols defined in IR files.
-
-* LLVM now always uses cfi directives for producing most stack
- unwinding information.
-
-* The prefix for loop vectorizer hint metadata has been changed from
- ``llvm.vectorizer`` to ``llvm.loop.vectorize``.
-
.. NOTE
For small 1-3 sentence descriptions, just add an entry at the end of
this list. If your description won't fit comfortably in one bullet
functionality, or simply have a lot to talk about), see the `NOTE` below
for adding a new subsection.
+* Support for AuroraUX has been removed.
+
+* Added support for a `native object file-based bitcode wrapper format
+ <BitCodeFormat.html#native-object-file>`_.
+
* ... next change ...
.. NOTE
Makes programs 10x faster by doing Special New Thing.
+Prefix data rework
+------------------
+
+The semantics of the ``prefix`` attribute have been changed. Users
+that want the previous ``prefix`` semantics should instead use
+``prologue``. To motivate this change, let's examine the primary
+usecases that these attributes aim to serve,
+
+ 1. Code sanitization metadata (e.g. Clang's undefined behavior
+ sanitizer)
+
+ 2. Function hot-patching: Enable the user to insert ``nop`` operations
+ at the beginning of the function which can later be safely replaced
+ with a call to some instrumentation facility.
+
+ 3. Language runtime metadata: Allow a compiler to insert data for
+ use by the runtime during execution. GHC is one example of a
+ compiler that needs this functionality for its
+ tables-next-to-code functionality.
+
+Previously ``prefix`` served cases (1) and (2) quite well by allowing the user
+to introduce arbitrary data at the entrypoint but before the function
+body. Case (3), however, was poorly handled by this approach as it
+required that prefix data was valid executable code.
+
+In this release the concept of prefix data has been redefined to be
+data which occurs immediately before the function entrypoint (i.e. the
+symbol address). Since prefix data now occurs before the function
+entrypoint, there is no need for the data to be valid code.
+
+The previous notion of prefix data now goes under the name "prologue
+data" to emphasize its duality with the function epilogue.
+
+The intention here is to handle cases (1) and (2) with prologue data and
+case (3) with prefix data. See the language reference for further details
+on the semantics of these attributes.
+
+This refactoring arose out of discussions_ with Reid Kleckner in
+response to a proposal to introduce the notion of symbol offsets to
+enable handling of case (3).
+
+.. _discussions: http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-May/073235.html
+
+
Changes to the ARM Backend
--------------------------
-Since release 3.3, a lot of new features have been included in the ARM
-back-end but weren't production ready (ie. well tested) on release 3.4.
-Just after the 3.4 release, we started heavily testing two major parts
-of the back-end: the integrated assembler (IAS) and the ARM exception
-handling (EHABI), and now they are enabled by default on LLVM/Clang.
-
-The IAS received a lot of GNU extensions and directives, as well as some
-specific pre-UAL instructions. Not all remaining directives will be
-implemented, as we made judgement calls on the need versus the complexity,
-and have chosen simplicity and future compatibility where hard decisions
-had to be made. The major difference is, as stated above, the IAS validates
-all inline ASM, not just for object emission, and that cause trouble with
-some uses of inline ASM as pre-processor magic.
-
-So, while the IAS is good enough to compile large projects (including most
-of the Linux kernel), there are a few things that we can't (and probably
-won't) do. For those cases, please use ``-fno-integrated-as`` in Clang.
-
-Exception handling is another big change. After extensive testing and
-changes to cooperate with Dwarf unwinding, EHABI is enabled by default.
-The options ``-arm-enable-ehabi`` and ``-arm-enable-ehabi-descriptors``,
-which were used to enable EHABI in the previous releases, are removed now.
-
-This means all ARM code will emit EH unwind tables, or CFI unwinding (for
-debug/profiling), or both. To avoid run-time inconsistencies, C code will
-also emit EH tables (in case they interoperate with C++ code), as is the
-case for other architectures (ex. x86_64).
-
-External Open Source Projects Using LLVM 3.5
+ During this release ...
+
+
+Changes to the MIPS Target
+--------------------------
+
+During this release ...
+
+Changes to the PowerPC Target
+-----------------------------
+
+During this release ...
+
+External Open Source Projects Using LLVM 3.6
============================================
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 3.5.
+projects that have already been updated to work with LLVM 3.6.
+
+* A project
Additional Information
projects / oota-llvm.git / blobdiff