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17
18<h1>Clang 3.0 Release Notes</h1>
19
20<img align=right src="http://llvm.org/img/DragonSmall.png"
21 width="136" height="136" alt="LLVM Dragon Logo">
22
23<ul>
24 <li><a href="#intro">Introduction</a></li>
25 <li><a href="#whatsnew">What's New in Clang 3.0?</a>
26 <ul>
27 <li><a href="#majorfeatures">Major New Features</a></li>
28 <li><a href="#cchanges">C Language Changes</a></li>
29 <li><a href="#cxxhanges">C++ Language Changes</a></li>
30 <li><a href="#objchanges">Objective-C Language Changes</a></li>
31 <li><a href="#apichanges">Internal API Changes</a></li>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]32 </ul>
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]33 </li>
34 <li><a href="#knownproblems">Known Problems</a></li>
35 <li><a href="#additionalinfo">Additional Information</a></li>
36</ul>
37
38<div class="doc_author">
39 <p>Written by the <a href="http://llvm.org/">LLVM Team</a></p>
40</div>
41
42<!--
43<h1 style="color:red">These are in-progress notes for the upcoming LLVM 3.0
44release.<br>
45You may prefer the
46<a href="http://llvm.org/releases/2.9/docs/ReleaseNotes.html">LLVM 2.9
47Release Notes</a>.</h1>
48 -->
49
50<!-- ======================================================================= -->
51<h2 id="intro">Introduction</h2>
52<!-- ======================================================================= -->
53
54<p>This document contains the release notes for the Clang C/C++/Objective-C
55frontend, part of the LLVM Compiler Infrastructure, release 3.0. Here we
56describe the status of Clang in some detail, including major improvements from
57the previous release and new feature work. For the general LLVM release notes,
58see <a href ="http;//llvm.org/docs/ReleaseNotes.html">the LLVM
59 documentation</a>. All LLVM releases may be downloaded from the
60<a href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
61
62<p>For more information about Clang or LLVM, including information about the
63latest release, please check out the main please see the
64<a href="http://clang.llvm.org">Clang Web Site</a> or the
65<a href="http://llvm.org">LLVM Web Site</a>.
66
67<p>Note that if you are reading this file from a Subversion checkout or the main
68Clang web page, this document applies to the <i>next</i> release, not the
69current one. To see the release notes for a specific release, please see the
70<a href="http://llvm.org/releases/">releases page</a>.</p>
71
72<!-- ======================================================================= -->
73<h2 id="whatsnew">What's New in Clang 3.0?</h2>
74<!-- ======================================================================= -->
75
76<p>Some of the major new features and improvements to Clang are listed here.
77Generic improvements to Clang as a whole or two its underlying infrastructure
78are described first, followed by language-specific sections with improvements to
79Clang's support for those languages.</p>
80
81<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
82<h3 id="majorfeatures">Major New Features</h3>
83<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
84
Chandler Carrutha3950cc2011-11-28 08:41:06 +0000[diff] [blame]85<h4 id="notes">Unorganized Notes</h4>
86<p>These are completely random notes as I'm organizing my thoughts and reviewing
87the history. Anything still here needs to be distilled and turned into proper
88prose in a section of its own. When doing that, delete the notes.</p>
89<ul>
Chandler Carrutha3950cc2011-11-28 08:41:06 +0000[diff] [blame]90 <li>OS Availability attribute -- r128127</li>
91 <li>GNU ObjectiveC Runtime support -- David Chisnall</li>
Chandler Carruth1af40222011-11-28 09:43:30 +0000[diff] [blame]92 <li>Improved AST support for partially constructed nodes and incomplete
93 information for LLDB and other clients which dynamically build AST nodes.</li>
Chandler Carruth1af40222011-11-28 09:43:30 +0000[diff] [blame]94 <li>Memory reduction -- initializers, macro expansions, source locations,
95 etc.</li>
Chandler Carruthb6a1d9d2011-11-28 11:27:33 +0000[diff] [blame]96 <li>ObjC ARC -- get a blurb from rjmccall</li>
Douglas Gregora1e3e8c2011-11-28 17:51:39 +0000[diff] [blame]97 <li>ObjC related result type/instancetype</li>
Chandler Carruth7717ce42011-11-28 12:24:23 +0000[diff] [blame]98 <li>Thread Safety attributes and correctness analysis added to Clang.</li>
Chandler Carruth7a1f1482011-11-28 13:02:29 +0000[diff] [blame]99 <li>Major improvements to the interactions between serializing and
100 deserializing the AST and the preprocessor -- argiris</li>
Chandler Carrutha3950cc2011-11-28 08:41:06 +0000[diff] [blame]101</ul>
102
Chandler Carruth58f2cbc2011-11-28 22:34:59 +0000[diff] [blame]103<h4 id="diagnostics">A multitude of improvements to Clang's diagnostics</h4>
104Clang's diagnostics are constantly being improved to catch more issues, explain
105them more clearly, and provide more accurate source information about them.
106A few improvements since the 2.9 release that have a particularly high impact:
107<ul>
108 <li>Substantially shorter messages due to better recovery, fewer include
109 stacks, and tuning verbose features such as 'a.k.a.' type printing.</li>
110 <li>
111 Able to recover and correct from misspelled type names at the begging of statements. For example, Clang now emits:
Richard Smithad5459a2011-11-28 23:16:15 +0000[diff] [blame^]112 <pre><b>t.c:6:3: <span class="error">error:</span> use of undeclared identifier 'integer'; did you mean 'Integer'?</b>
Chandler Carruth58f2cbc2011-11-28 22:34:59 +0000[diff] [blame]113 integer *i = 0;
Richard Smithad5459a2011-11-28 23:16:15 +0000[diff] [blame^]114 <span class="caret">^~~~~~~</span>
Chandler Carruth58f2cbc2011-11-28 22:34:59 +0000[diff] [blame]115 Integer
Richard Smithad5459a2011-11-28 23:16:15 +0000[diff] [blame^]116<b>t.c:1:13: note:</b> 'Integer' declared here
Chandler Carruth58f2cbc2011-11-28 22:34:59 +0000[diff] [blame]117typedef int Integer;
Richard Smithad5459a2011-11-28 23:16:15 +0000[diff] [blame^]118 <span class="caret">^</span></pre>
Chandler Carruth58f2cbc2011-11-28 22:34:59 +0000[diff] [blame]119 </li>
120 <li>Expanded typo correction to (among other improvements) look across
121 namespaces and suggest namespace qualifiers in addition to misspellings of the
122 identifier itself.</li>
123 <li>More rich macro expansion backtraces and some (limited) fix-it hints when
124 diagnostics stem from macro arguments.</li>
Chandler Carruth2f376852011-11-28 22:54:33 +0000[diff] [blame]125 <li>Many new warnings have been added to catch common, bug-prone code
126 patterns.</li>
127 <li>Uninitialized values Clang warning was rewritten to be more accurate,
128 faster, and able to differentiate between the <em>possibility</em> of an
129 uninitialized use and the <em>certainty</em> of an uninitialized use.</li>
Chandler Carruth58f2cbc2011-11-28 22:34:59 +0000[diff] [blame]130</ul>
131
Chandler Carruth9a167122011-11-28 22:43:32 +0000[diff] [blame]132<h4 id="libclang">This release saw significant improvements to <code>libclang</code></h4>
133<ul>
134 <li>A broader set of the <code>libclang</code> API is exposed in the Python
135 bindings.</li>
136 <li>Much more of the Clang AST is exposed through <code>libclang</code>'s APIs
137 and cursors.</li>
138 <li>Cursors can now walk more effectively through macros, especially arguments
139 to function-style macros, and resolve to the underlying AST.</li>
140 <li>Improved code completion surrounding macros, macro arguments, and
141 token pasting.</li>
142 <li>Improved code completion for in-class member functions.</li>
143 <li>Crash recovery for <code>libclang</code> clients.</li>
144 <!-- Doug or Ted may want to flesh this out if there are relevant details I'm
145 glossing over... -->
146</ul>
147
Chandler Carruthb882a1d2011-11-28 21:56:30 +0000[diff] [blame]148<h4 id="driver">The Clang GCC-compatible command-line driver improved dramatically</h4>
149A great deal of work went into the GCC-compatible driver for the 3.0 release
150making it support more operating systems, emulate GCC behavior more accurately,
151and support a much broader range of Linux distributions out of the box.
152<ul>
153 <li>More accurate support for hardware architecture pre-defined macros (e.g.,
154 __i686__).</li>
155 <li>Robust library and header search paths for the vast majority of x86 and
156 x86-64 Linux distributions.</li>
157 <li>Improved support for newer Darwin platforms.</li>
158 <li>Partial support for <code>--sysroot=...</code> based cross-compiling on
159 Linux (and similar) host systems.</li>
160 <li>Improved support for locating and using libcxx when installed, especially
161 on Darwin.</li>
162 <!-- There are likely more Darwin-specific improvements to mention here? -->
163 <!-- What support was added for FreeBSD? NetBSD? Anything noteworthy? -->
Chandler Carruth2f376852011-11-28 22:54:33 +0000[diff] [blame]164 <li>Automatic detection of Clang crashes in the driver and preparation of
165 reproduction steps for filing bug reports.</li><!-- Chad, feel free to add
166 more details here. -->
Chandler Carruthb882a1d2011-11-28 21:56:30 +0000[diff] [blame]167</ul>
168
Chandler Carruthc6f2af32011-11-28 19:17:25 +0000[diff] [blame]169<h4 id="ppcallbacks">Expanded support for instrumenting the preprocessor through
170 callbacks</h4>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]171Several enhancements were made to the <code>PPCallbacks</code> interface to
172expand the information available to tools and library users of Clang that wish
173to introspect the preprocessing.
Chandler Carruthc6f2af32011-11-28 19:17:25 +0000[diff] [blame]174<ul>
175 <li>The exact text used between the <code>""</code>s or <code>&lt;&gt;</code>s is reported.</li>
176 <li>The header search path used to locate the header is reported.</li>
177 <li>Missing files during including headers reported.</li>
178 <li>The exact source range for expanded macros can be retrieved.</li>
179</ul>
180
Chandler Carruth185e9302011-11-28 23:11:27 +0000[diff] [blame]181<h4 id="windows">Clang is building and tested regularly on Windows and can
182 compile limited subsets of code on Windows</h4>
183Clang is regularly built and tested on a variety of Windows platforms including
184MinGW 32-bit and 64-bit, Cygwin, and natively with MSVC. In addition, Clang can
185be used as a compiler in a few Windows contexts.
186<ul>
187 <li>Normal compilation supported for the MinGW target platform, in both 32-bit
188 and 64-bit, and the Cygwin target platform.</li>
189 <li>Parsing and AST support for Windows Structured Exception Handling.</li>
190 <li>Initial support for some MSVC language extensions and the ability to parse
191 a few native MSVC system headers.</li>
192</ul>
193
Chandler Carrutha0df07d2011-11-28 22:17:58 +0000[diff] [blame]194<!--
Chandler Carruth9c353042011-11-28 23:02:13 +0000[diff] [blame]195Nick and/or Rafael will flesh this out into a bit about the CFI / DWARF
196improvements.
197
198<h4 id="dwarf">DWARF Exception Handling uses CFI...</h4>
199Rafael had a zillion patches to emit stuff using .cfi directives... =]
200
201-->
202
203<!--
Chandler Carrutha0df07d2011-11-28 22:17:58 +0000[diff] [blame]204Need Peter and/or Tanya to flesh this out if we want it in 3.0's notes.. The
205state isn't clear just from documentation or commit logs.
206
207<h4 id="opencl">Initial work to support compiling OpenCL with Clang</h4>
208Clang has some (limited) support for compiling OpenCL.
209-->
210
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]211<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
212<h3 id="cchanges">C Language Changes in Clang</h3>
213<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
214
Richard Smith62d730f2011-11-28 22:48:25 +0000[diff] [blame]215<h4 id="c1xchanges">C1X Feature Support</h4>
216
217<p>Clang 3.0 adds support for the
218<a href="http://clang.llvm.org/docs/LanguageExtensions.html#c1x">
219<code>_Alignas</code>, <code>_Generic</code>, and <code>_Static_assert</code>
220keywords</a>, drafted for inclusion in the next C standard, which is
221provisionally known as C1X. Use <code>-std=c1x</code> or <code>-std=gnu1x</code>
222to enable support for the new language standard. These features are
223backwards-compatible and are available as an extension in all language
224modes.</p>
225
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]226<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
227<h3 id="cxxchanges">C++ Language Changes in Clang</h3>
228<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
229
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]230<h4 id="cxx11changes">C++11 Feature Support</h4>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]231<p>Clang 3.0 adds support for
232<a href="http://clang.llvm.org/cxx_status.html#cxx11">more of the language
233features</a> added in the latest ISO C++ standard, C++11. Use
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]234<code>-std=c++11</code> or <code>-std=gnu++11</code> to enable support for these
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]235features. The following are now considered to be of production quality:
236<ul>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]237 <li>Range-based <code>for</code> loops</li>
238 <li>Alias declarations (a new syntax for <code>typedef</code> declarations),
239 including their <code>template</code> forms</li>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]240 <li>Specifying default values for class data members within a class
241 definition</li>
242 <li>Constructors delegating to other constructors of the same class</li>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]243 <li>The <code>override</code> context-sensitive keyword for virtual member
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]244 function declarations</li>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]245 <li>Explicitly generating default function definitions with
246 <code>= default</code></li>
247 <li>The <code>nullptr</code> keyword, and the corresponding type</li>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]248 <li>Raw string literals with arbitary delimiters (for instance,
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]249 <code>R"delim(str"ing)delim"</code>)</li>
250 <li>Unicode string literals (for instance, <code>U"\u1234"</code>) and the
251 <code>char16_t</code> and <code>char32_t</code> built-in types
252 <li><code>noexcept</code> expressions and the <code>noexcept</code> specifier
253 on function declarations</li>
254 <li><code>alignof</code> expressions and the <code>alignas</code> specifier on
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]255 variable declarations</li>
256 <li>A full set of <a href="http://clang.llvm.org/docs/LanguageExtensions.html#checking_type_traits">type traits</a>,
257 sufficient to support C++11 standard libraries</li>
258</ul>
Chandler Carruthbc02a042011-11-28 21:55:34 +0000[diff] [blame]259All warning and language selection flags which previously accepted
260<code>c++0x</code> now accept <code>c++11</code>. The old <code>c++0x</code>
261form remains as an alias.
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]262
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]263<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
264<h3 id="objcchanges">Objective-C Language Changes in Clang</h3>
265<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
266
267<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
268<h3 id="apichanges">Internal API Changes</h3>
269<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
270
Chandler Carruthc4dbffa2011-11-28 18:55:47 +0000[diff] [blame]271These are major API changes that have happened since the 2.9 release of Clang.
272If upgrading an external codebase that uses Clang as a library, this section
273should help get you past the largest hurdles of upgrading.
274
Chandler Carruth7d727b72011-11-28 19:06:34 +0000[diff] [blame]275<h4 id="macroexpansion">Switched terminology from "instantiation" to "expansion"
276 for macros</h4>
277A great deal of comments and code changes fell out of this, but also every API
278relating to macros with the word "instantiation" (or some variant thereof) was
279renamed. An incomplete list of the most note-worthy ones is here:
280<ul>
281 <li><code>MacroInstantiation</code> became <code>MacroExpansion</code></li>
282 <li><code>SourceManager::getInstantiationLoc</code> became
283 <code>SourceManager::getExpansionLoc</code></li>
284 <li><code>SourceManager::getInstantiationRange</code> became
285 <code>SourceManager::getExpansionRange</code></li>
286 <li><code>SourceManager::getImmediateInstantiationRange</code> became
287 <code>SourceManager::getImmediateExpansionRange</code></li>
288 <li><code>SourceManager::getDecomposedInstantiationLoc</code> became
289 <code>SourceManager::getDecomposedExpansionLoc</code></li>
290 <li><code>SourceManager::getInstantiationColumnNumber</code> became
291 <code>SourceManager::getExpansionColumnNumber</code></li>
292 <li><code>SourceManager::getInstantiationLineNumber</code> became
293 <code>SourceManager::getExpansionLineNumber</code></li>
294 <!-- TODO: Make this more complete! -->
295</ul>
296
Chandler Carruthc4dbffa2011-11-28 18:55:47 +0000[diff] [blame]297<h4 id="diagnosticrename">Diagnostic class names were shuffled</h4>
298<ul>
299 <li><code>Diagnostic</code> became <code>DiagnosticEngine</code></li>
300 <li><code>DiagnosticClient</code> became <code>DiagnosticConsumer</code></li>
301 <li><code>DiagnosticInfo</code> became <code>Diagnostic</code></li>
302</ul>
303Subclasses of <code>DiagnosticConsumer</code> were also then renamed to end with
304<code>Consumer</code>.
305
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]306<!-- ======================================================================= -->
307<h2 id="knownproblems">Significant Known Problems</h2>
308<!-- ======================================================================= -->
309
310<!-- ======================================================================= -->
311<h2 id="additionalinfo">Additional Information</h2>
312<!-- ======================================================================= -->
313
314<p>A wide variety of additional information is available on the
315<a href="http://clang.llvm.org/">Clang web page</a>. The web page contains
316versions of the API documentation which are up-to-date with the Subversion
317version of the source code. You can access versions of these documents specific
318to this release by going into the "<tt>clang/doc/</tt>" directory in the Clang
319tree.</p>
320
321<p>If you have any questions or comments about Clang, please feel free to
322contact us via the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">
323mailing list</a>.</p>
324
Chandler Carruth59abf062011-11-28 22:12:44 +0000[diff] [blame]325
326<!-- ======================================================================= -->
327<!-- Likely 3.1 release notes -->
328<!-- ======================================================================= -->
329<!--
330This is just a section to hold things that have already gotten started and
331should likely pick up proper release notes in 3.1.
332
333- C1X and C++11 atomics infrastructure and support
334- CUDA support?
335
336-->
337
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]338</body>
339</html>