======================
-LLVM 3.4 Release Notes
+LLVM 3.5 Release Notes
======================
.. contents::
:local:
.. warning::
- These are in-progress notes for the upcoming LLVM 3.4 release. You may
- prefer the `LLVM 3.3 Release Notes <http://llvm.org/releases/3.3/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 3.4. 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/>`_.
functionality, or simply have a lot to talk about), see the `NOTE` below
for adding a new subsection.
-* This is expected to be the last release of LLVM which compiles using a C++98
- toolchain. We expect to start using some C++11 features in LLVM and other
- sub-projects starting after this release. That said, we are committed to
- supporting a reasonable set of modern C++ toolchains as the host compiler on
- all of the platforms. This will at least include Visual Studio 2012 on
- Windows, and Clang 3.1 or GCC 4.7.x on Mac and Linux. The final set of
- compilers (and the C++11 features they support) is not set in stone, but we
- wanted users of LLVM to have a heads up that the next release will involve
- a substantial change in the host toolchain requirements.
+* Support for AuroraUX has been removed.
-* The regression tests now fail if any command in a pipe fails. To disable it in
- a directory, just add ``config.pipefail = False`` to its ``lit.local.cfg``.
- See :doc:`Lit <CommandGuide/lit>` for the details.
+* Added support for a `native object file-based bitcode wrapper format
+ <BitCodeFormat.html#native-object-file>`_.
-* Support for exception handling has been removed from the old JIT. Use MCJIT
- if you need EH support.
+* ... next change ...
-* The R600 backend is not marked experimental anymore and is built by default.
+.. NOTE
+ If you would like to document a larger change, then you can add a
+ subsection about it right here. You can copy the following boilerplate
+ and un-indent it (the indentation causes it to be inside this comment).
-* APFloat::isNormal() was renamed to APFloat::isFiniteNonZero() and
- APFloat::isIEEENormal() was renamed to APFloat::isNormal(). This ensures that
- APFloat::isNormal() conforms to IEEE-754R-2008.
+ Special New Feature
+ -------------------
-* The library call simplification pass has been removed. Its functionality
- has been integrated into the instruction combiner and function attribute
- marking passes.
+ Makes programs 10x faster by doing Special New Thing.
-* Support for building using Visual Studio 2008 has been dropped. Use VS 2010
- or later instead. For more information, see the `Getting Started using Visual
- Studio <GettingStartedVS.html>`_ page.
+Prefix data rework
+------------------
-* The Loop Vectorizer that was previously enabled for -O3 is now enabled for
- -Os and -O2.
+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,
-* The new SLP Vectorizer is now enabled by default.
+ 1. Code sanitization metadata (e.g. Clang's undefined behavior
+ sanitizer)
-* llvm-ar now uses the new Object library and produces archives and
- symbol tables in the gnu format.
+ 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.
-* FileCheck now allows specifing -check-prefix multiple times. This
- helps reduce duplicate check lines when using multiple RUN lines.
+ 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.
-* ... next change ...
+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.
-.. NOTE
- If you would like to document a larger change, then you can add a
- subsection about it right here. You can copy the following boilerplate
- and un-indent it (the indentation causes it to be inside this comment).
+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.
- Special New Feature
- -------------------
+The previous notion of prefix data now goes under the name "prologue
+data" to emphasize its duality with the function epilogue.
- Makes programs 10x faster by doing Special New Thing.
+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).
-External Open Source Projects Using LLVM 3.4
-============================================
+.. _discussions: http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-May/073235.html
-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 3.4.
+
+Changes to the ARM Backend
+--------------------------
+
+ During this release ...
-LDC - the LLVM-based D compiler
--------------------------------
+Changes to the MIPS Target
+--------------------------
-`D <http://dlang.org>`_ is a language with C-like syntax and static typing. It
-pragmatically combines efficiency, control, and modeling power, with safety and
-programmer productivity. D supports powerful concepts like Compile-Time Function
-Execution (CTFE) and Template Meta-Programming, provides an innovative approach
-to concurrency and offers many classical paradigms.
+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 3.6.
-`LDC <http://wiki.dlang.org/LDC>`_ uses the frontend from the reference compiler
-combined with LLVM as backend to produce efficient native code. LDC targets
-x86/x86_64 systems like Linux, OS X, FreeBSD and Windows and also Linux/PPC64.
-Ports to other architectures like ARM and AArch64 are underway.
+* A project
Additional Information
projects / oota-llvm.git / blobdiff