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