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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>
Francois Pichet551988f2011-11-28 23:30:46 +0000[diff] [blame^]190 <li>New -fms-compatibility flag to handle MSVC constructs that could change
191 the meaning of an otherwise well formed program</li>
192 <li>clang can now parse all the MSVC 2010 standard C++ header files
193 in the nominal case, (still need to specifiy -nobuiltininc for some headers).</li>
194 <li>Improved support for MFC code parsing, (still a work in progress).</li>
Chandler Carruth185e9302011-11-28 23:11:27 +0000[diff] [blame]195</ul>
196
Chandler Carrutha0df07d2011-11-28 22:17:58 +0000[diff] [blame]197<!--
Chandler Carruth9c353042011-11-28 23:02:13 +0000[diff] [blame]198Nick and/or Rafael will flesh this out into a bit about the CFI / DWARF
199improvements.
200
201<h4 id="dwarf">DWARF Exception Handling uses CFI...</h4>
202Rafael had a zillion patches to emit stuff using .cfi directives... =]
203
204-->
205
206<!--
Chandler Carrutha0df07d2011-11-28 22:17:58 +0000[diff] [blame]207Need Peter and/or Tanya to flesh this out if we want it in 3.0's notes.. The
208state isn't clear just from documentation or commit logs.
209
210<h4 id="opencl">Initial work to support compiling OpenCL with Clang</h4>
211Clang has some (limited) support for compiling OpenCL.
212-->
213
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]214<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
215<h3 id="cchanges">C Language Changes in Clang</h3>
216<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
217
Richard Smith62d730f2011-11-28 22:48:25 +0000[diff] [blame]218<h4 id="c1xchanges">C1X Feature Support</h4>
219
220<p>Clang 3.0 adds support for the
221<a href="http://clang.llvm.org/docs/LanguageExtensions.html#c1x">
222<code>_Alignas</code>, <code>_Generic</code>, and <code>_Static_assert</code>
223keywords</a>, drafted for inclusion in the next C standard, which is
224provisionally known as C1X. Use <code>-std=c1x</code> or <code>-std=gnu1x</code>
225to enable support for the new language standard. These features are
226backwards-compatible and are available as an extension in all language
227modes.</p>
228
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]229<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
230<h3 id="cxxchanges">C++ Language Changes in Clang</h3>
231<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
232
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]233<h4 id="cxx11changes">C++11 Feature Support</h4>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]234<p>Clang 3.0 adds support for
235<a href="http://clang.llvm.org/cxx_status.html#cxx11">more of the language
236features</a> added in the latest ISO C++ standard, C++11. Use
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]237<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]238features. The following are now considered to be of production quality:
239<ul>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]240 <li>Range-based <code>for</code> loops</li>
241 <li>Alias declarations (a new syntax for <code>typedef</code> declarations),
242 including their <code>template</code> forms</li>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]243 <li>Specifying default values for class data members within a class
244 definition</li>
245 <li>Constructors delegating to other constructors of the same class</li>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]246 <li>The <code>override</code> context-sensitive keyword for virtual member
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]247 function declarations</li>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]248 <li>Explicitly generating default function definitions with
249 <code>= default</code></li>
250 <li>The <code>nullptr</code> keyword, and the corresponding type</li>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]251 <li>Raw string literals with arbitary delimiters (for instance,
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]252 <code>R"delim(str"ing)delim"</code>)</li>
253 <li>Unicode string literals (for instance, <code>U"\u1234"</code>) and the
254 <code>char16_t</code> and <code>char32_t</code> built-in types
255 <li><code>noexcept</code> expressions and the <code>noexcept</code> specifier
256 on function declarations</li>
257 <li><code>alignof</code> expressions and the <code>alignas</code> specifier on
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]258 variable declarations</li>
259 <li>A full set of <a href="http://clang.llvm.org/docs/LanguageExtensions.html#checking_type_traits">type traits</a>,
260 sufficient to support C++11 standard libraries</li>
261</ul>
Chandler Carruthbc02a042011-11-28 21:55:34 +0000[diff] [blame]262All warning and language selection flags which previously accepted
263<code>c++0x</code> now accept <code>c++11</code>. The old <code>c++0x</code>
264form remains as an alias.
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]265
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]266<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
267<h3 id="objcchanges">Objective-C Language Changes in Clang</h3>
268<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
269
270<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
271<h3 id="apichanges">Internal API Changes</h3>
272<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
273
Chandler Carruthc4dbffa2011-11-28 18:55:47 +0000[diff] [blame]274These are major API changes that have happened since the 2.9 release of Clang.
275If upgrading an external codebase that uses Clang as a library, this section
276should help get you past the largest hurdles of upgrading.
277
Chandler Carruth7d727b72011-11-28 19:06:34 +0000[diff] [blame]278<h4 id="macroexpansion">Switched terminology from "instantiation" to "expansion"
279 for macros</h4>
280A great deal of comments and code changes fell out of this, but also every API
281relating to macros with the word "instantiation" (or some variant thereof) was
282renamed. An incomplete list of the most note-worthy ones is here:
283<ul>
284 <li><code>MacroInstantiation</code> became <code>MacroExpansion</code></li>
285 <li><code>SourceManager::getInstantiationLoc</code> became
286 <code>SourceManager::getExpansionLoc</code></li>
287 <li><code>SourceManager::getInstantiationRange</code> became
288 <code>SourceManager::getExpansionRange</code></li>
289 <li><code>SourceManager::getImmediateInstantiationRange</code> became
290 <code>SourceManager::getImmediateExpansionRange</code></li>
291 <li><code>SourceManager::getDecomposedInstantiationLoc</code> became
292 <code>SourceManager::getDecomposedExpansionLoc</code></li>
293 <li><code>SourceManager::getInstantiationColumnNumber</code> became
294 <code>SourceManager::getExpansionColumnNumber</code></li>
295 <li><code>SourceManager::getInstantiationLineNumber</code> became
296 <code>SourceManager::getExpansionLineNumber</code></li>
297 <!-- TODO: Make this more complete! -->
298</ul>
299
Chandler Carruthc4dbffa2011-11-28 18:55:47 +0000[diff] [blame]300<h4 id="diagnosticrename">Diagnostic class names were shuffled</h4>
301<ul>
302 <li><code>Diagnostic</code> became <code>DiagnosticEngine</code></li>
303 <li><code>DiagnosticClient</code> became <code>DiagnosticConsumer</code></li>
304 <li><code>DiagnosticInfo</code> became <code>Diagnostic</code></li>
305</ul>
306Subclasses of <code>DiagnosticConsumer</code> were also then renamed to end with
307<code>Consumer</code>.
308
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]309<!-- ======================================================================= -->
310<h2 id="knownproblems">Significant Known Problems</h2>
311<!-- ======================================================================= -->
312
313<!-- ======================================================================= -->
314<h2 id="additionalinfo">Additional Information</h2>
315<!-- ======================================================================= -->
316
317<p>A wide variety of additional information is available on the
318<a href="http://clang.llvm.org/">Clang web page</a>. The web page contains
319versions of the API documentation which are up-to-date with the Subversion
320version of the source code. You can access versions of these documents specific
321to this release by going into the "<tt>clang/doc/</tt>" directory in the Clang
322tree.</p>
323
324<p>If you have any questions or comments about Clang, please feel free to
325contact us via the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">
326mailing list</a>.</p>
327
Chandler Carruth59abf062011-11-28 22:12:44 +0000[diff] [blame]328
329<!-- ======================================================================= -->
330<!-- Likely 3.1 release notes -->
331<!-- ======================================================================= -->
332<!--
333This is just a section to hold things that have already gotten started and
334should likely pick up proper release notes in 3.1.
335
336- C1X and C++11 atomics infrastructure and support
337- CUDA support?
338
339-->
340
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]341</body>
342</html>