1========================
2LLVM 4.0.0 Release Notes
3========================
4
5.. contents::
6    :local:
7
8.. warning::
9   These are in-progress notes for the upcoming LLVM 4.0.0 release.  You may
10   prefer the `LLVM 3.9 Release Notes <http://llvm.org/releases/3.9.0/docs
11   /ReleaseNotes.html>`_.
12
13
14Introduction
15============
16
17This document contains the release notes for the LLVM Compiler Infrastructure,
18release 4.0.0.  Here we describe the status of LLVM, including major improvements
19from the previous release, improvements in various subprojects of LLVM, and
20some of the current users of the code.  All LLVM releases may be downloaded
21from the `LLVM releases web site <http://llvm.org/releases/>`_.
22
23For more information about LLVM, including information about the latest
24release, please check out the `main LLVM web site <http://llvm.org/>`_.  If you
25have questions or comments, the `LLVM Developer's Mailing List
26<http://lists.llvm.org/mailman/listinfo/llvm-dev>`_ is a good place to send
27them.
28
29Note that if you are reading this file from a Subversion checkout or the main
30LLVM web page, this document applies to the *next* release, not the current
31one.  To see the release notes for a specific release, please see the `releases
32page <http://llvm.org/releases/>`_.
33
34Non-comprehensive list of changes in this release
35=================================================
36* The C API functions LLVMAddFunctionAttr, LLVMGetFunctionAttr,
37  LLVMRemoveFunctionAttr, LLVMAddAttribute, LLVMRemoveAttribute,
38  LLVMGetAttribute, LLVMAddInstrAttribute and
39  LLVMRemoveInstrAttribute have been removed.
40
41* The C API enum LLVMAttribute has been deleted.
42
43.. NOTE
44   For small 1-3 sentence descriptions, just add an entry at the end of
45   this list. If your description won't fit comfortably in one bullet
46   point (e.g. maybe you would like to give an example of the
47   functionality, or simply have a lot to talk about), see the `NOTE` below
48   for adding a new subsection.
49
50* The definition and uses of LLVM_ATRIBUTE_UNUSED_RESULT in the LLVM source
51  were replaced with LLVM_NODISCARD, which matches the C++17 [[nodiscard]]
52  semantics rather than gcc's __attribute__((warn_unused_result)).
53
54* Minimum compiler version to build has been raised to GCC 4.8 and VS 2015.
55
56* The Timer related APIs now expect a Name and Description. When upgrading code
57  the previously used names should become descriptions and a short name in the
58  style of a programming language identifier should be added.
59
60* ... next change ...
61
62.. NOTE
63   If you would like to document a larger change, then you can add a
64   subsection about it right here. You can copy the following boilerplate
65   and un-indent it (the indentation causes it to be inside this comment).
66
67   Special New Feature
68   -------------------
69
70   Makes programs 10x faster by doing Special New Thing.
71
72Changes to the LLVM IR
73----------------------
74
75Changes to the ARM Backend
76--------------------------
77
78 During this release ...
79
80
81Changes to the MIPS Target
82--------------------------
83
84 During this release ...
85
86
87Changes to the PowerPC Target
88-----------------------------
89
90 During this release ...
91
92Changes to the X86 Target
93-------------------------
94
95 During this release ...
96
97Changes to the AMDGPU Target
98-----------------------------
99
100 During this release ...
101
102Changes to the AVR Target
103-----------------------------
104
105* The entire backend has been merged in-tree with all tests passing. All of
106  the instruction selection code and the machine code backend has landed
107  recently and is fully usable.
108
109Changes to the OCaml bindings
110-----------------------------
111
112* The attribute API was completely overhauled, following the changes
113  to the C API.
114
115
116External Open Source Projects Using LLVM 4.0.0
117==============================================
118
119* A project...
120
121
122Additional Information
123======================
124
125A wide variety of additional information is available on the `LLVM web page
126<http://llvm.org/>`_, in particular in the `documentation
127<http://llvm.org/docs/>`_ section.  The web page also contains versions of the
128API documentation which is up-to-date with the Subversion version of the source
129code.  You can access versions of these documents specific to this release by
130going into the ``llvm/docs/`` directory in the LLVM tree.
131
132If you have any questions or comments about LLVM, please feel free to contact
133us via the `mailing lists <http://llvm.org/docs/#maillist>`_.
134