1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
|
=======================
Clang 3.6 Release Notes
=======================
.. contents::
:local:
:depth: 2
Written by the `LLVM Team <http://llvm.org/>`_
Introduction
============
This document contains the release notes for the Clang C/C++/Objective-C
frontend, part of the LLVM Compiler Infrastructure, release 3.6. Here we
describe the status of Clang in some detail, including major
improvements from the previous release and new feature work. For the
general LLVM release notes, see `the LLVM
documentation <http://llvm.org/releases/3.6.0/docs/ReleaseNotes.html>`_.
All LLVM releases may be downloaded from the `LLVM releases web
site <http://llvm.org/releases/>`_.
For more information about Clang or LLVM, including information about
the latest release, please check out the main please see the `Clang Web
Site <http://clang.llvm.org>`_ or the `LLVM Web
Site <http://llvm.org>`_.
What's New in Clang 3.6?
========================
Some of the major new features and improvements to Clang are listed
here. Generic improvements to Clang as a whole or to its underlying
infrastructure are described first, followed by language-specific
sections with improvements to Clang's support for those languages.
Major New Features
------------------
- The __has_attribute built-in macro no longer queries for attributes across
multiple attribute syntaxes (GNU, C++11, __declspec, etc). Instead, it only
queries GNU-style attributes. With the addition of __has_cpp_attribute and
__has_declspec_attribute, this allows for more precise coverage of attribute
syntax querying.
- clang-format now supports formatting Java code.
Improvements to Clang's diagnostics
-----------------------------------
Clang's diagnostics are constantly being improved to catch more issues,
explain them more clearly, and provide more accurate source information
about them. The improvements since the 3.5 release include:
- Smarter typo correction. Clang now tries a bit harder to give a usable
suggestion in more cases, and can now successfully recover in more
situations where the suggestion changes how an expression is parsed.
- ...
New Compiler Flags
------------------
The option ....
The __EXCEPTIONS macro
----------------------
``__EXCEPTIONS`` is now defined when landing pads are emitted, not when c++ exceptions are enabled. The two can be different in Objective-C files: If C++ exceptions are disabled but Objective-C exceptions are enabled, landing pads will be emitted. Clang 3.6 is switching the behavior of ``__EXCEPTIONS``. Clang 3.5 confusingly changed the behavior of ``has_feature(cxx_exceptions)``, which used to be set if landing pads were emitted, but is now set if C++ exceptions are enabled. So there are 3 cases:
Clang before 3.5:
``__EXCEPTIONS`` is set if C++ exceptions are enabled, ``cxx_exceptions`` enabled if C++ or ObjC exceptions are enabled
Clang 3.5:
``__EXCEPTIONS`` is set if C++ exceptions are enabled, ``cxx_exceptions`` enabled if C++ exceptions are enabled
Clang 3.6:
``__EXCEPTIONS`` is set if C++ or ObjC exceptions are enabled, ``cxx_exceptions`` enabled if C++ exceptions are enabled
To reliably test if C++ exceptions are enabled, use ``__EXCEPTIONS && __has_feature(cxx_exceptions)``, else things won't work in all versions of clang in Objective-C++ files.
New Pragmas in Clang
-----------------------
Clang now supports the ...
Windows Support
---------------
- Many, many bug fixes.
- Clang can now self-host using the ``msvc`` environment on x86 and x64
Windows. This means that Microsoft C++ ABI is more or less feature-complete,
minus exception support.
- Added more MSVC compatibility hacks, such as allowing more lookup into
dependent bases of class templates when there is a known template pattern.
As a result, applications using Active Template Library (ATL) or Windows
Runtime Library (WRL) headers should compile correctly.
- Added support for the Visual C++ ``__super`` keyword.
- Added support for MSVC's ``__vectorcall`` calling convention, which is used
in the upcoming Visual Studio 2015 STL.
- Added basic support for DWARF debug information in COFF files.
C Language Changes in Clang
---------------------------
- The default language mode for C compilations with Clang has been changed from
C99 with GNU extensions to C11 with GNU extensions. C11 is largely
backwards-compatible with C99, but if you want to restore the former behavior
you can do so with the `-std=gnu99` flag.
C11 Feature Support
^^^^^^^^^^^^^^^^^^^
- Clang now provides an implementation of the standard C11 header `<stdatomic.h>`.
C++ Language Changes in Clang
-----------------------------
- An `upcoming change to C++ <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3922.html>_`
changes the semantics of certain deductions of `auto` from a braced initializer
list. Following the intent of the C++ committee, this change will be applied to
our C++11 and C++14 modes as well as our experimental C++17 mode. Clang 3.6
does not yet implement this change, but to provide a transition period, it
warns on constructs whose meaning will change. The fix in all cases is to
add an `=` prior to the left brace.
- Clang now supports putting identical constructors and destructors in
the C5/D5 comdat, reducing code duplication.
- Clang will put individual ``.init_array/.ctors`` sections in
comdats, reducing code duplication and speeding up startup.
C++17 Feature Support
^^^^^^^^^^^^^^^^^^^^^
Clang has experimental support for some proposed C++1z (tentatively, C++17)
features. This support can be enabled using the `-std=c++1z` flag.
New in Clang 3.6 is support for:
- Fold expressions
- `u8` character literals
- Nested namespace definitions: `namespace A::B { ... }` as a shorthand for
`namespace A { namespace B { ... } }`
- Attributes for namespaces and enumerators
- Constant evaluation for all non-type template arguments
Note that these features may be changed or removed in future Clang releases
without notice.
Support for `for (identifier : range)` as a synonym for
`for (auto &&identifier : range)` has been removed as it is no longer currently
considered for C++17.
For more details on C++ feature support, see
`the C++ status page <http://clang.llvm.org/cxx_status.html>`_.
Objective-C Language Changes in Clang
-------------------------------------
...
OpenCL C Language Changes in Clang
----------------------------------
...
OpenMP Language Changes in Clang
--------------------------------
Clang 3.6 contains codegen for many individual OpenMP pragmas, but combinations are not completed as yet.
We plan to continue codegen code drop aiming for completion in 3.7. Please see this link for up-to-date
`status <https://github.com/clang-omp/clang/wiki/Status-of-supported-OpenMP-constructs>_`.
LLVM's OpenMP runtime library, originally developed by Intel, has been modified to work on ARM, PowerPC,
as well as X86. The Runtime Library's compatibility with GCC 4.9 is improved
- missed entry points added, barrier and fork/join code improved, one more type of barrier enabled.
Support for ppc64le architecture is now available and automatically detected when using cmake system.
Using makefile the new "ppc64le" arch type is available.
Contributors to this work include AMD, Argonne National Lab., IBM, Intel, Texas Instruments, University of Houston and many others.
Internal API Changes
--------------------
These are major API changes that have happened since the 3.5 release of
Clang. If upgrading an external codebase that uses Clang as a library,
this section should help get you past the largest hurdles of upgrading.
...
libclang
--------
...
Static Analyzer
---------------
...
Core Analysis Improvements
==========================
- ...
New Issues Found
================
- ...
Python Binding Changes
----------------------
The following methods have been added:
- ...
Significant Known Problems
==========================
Additional Information
======================
A wide variety of additional information is available on the `Clang web
page <http://clang.llvm.org/>`_. The web page contains versions of the
API documentation which are up-to-date with the Subversion version of
the source code. You can access versions of these documents specific to
this release by going into the "``clang/docs/``" directory in the Clang
tree.
If you have any questions or comments about Clang, please feel free to
contact us via the `mailing
list <http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev>`_.
|
