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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 Carruthbba72a82011-11-28 10:57:14 +0000[diff] [blame]102 <li>CFI-based debug info -- nlewycky/espindola details</li>
Chandler Carruthb6a1d9d2011-11-28 11:27:33 +0000[diff] [blame]103 <li>ObjC ARC -- get a blurb from rjmccall</li>
Douglas Gregora1e3e8c2011-11-28 17:51:39 +0000[diff] [blame]104 <li>ObjC related result type/instancetype</li>
Chandler Carruth7717ce42011-11-28 12:24:23 +0000[diff] [blame]105 <li>Thread Safety attributes and correctness analysis added to Clang.</li>
Chandler Carruth7a1f1482011-11-28 13:02:29 +0000[diff] [blame]106 <li>Major improvements to the interactions between serializing and
107 deserializing the AST and the preprocessor -- argiris</li>
Chandler Carrutha3950cc2011-11-28 08:41:06 +0000[diff] [blame]108</ul>
109
Chandler Carruth58f2cbc2011-11-28 22:34:59 +0000[diff] [blame]110<h4 id="diagnostics">A multitude of improvements to Clang's diagnostics</h4>
111Clang's diagnostics are constantly being improved to catch more issues, explain
112them more clearly, and provide more accurate source information about them.
113A few improvements since the 2.9 release that have a particularly high impact:
114<ul>
115 <li>Substantially shorter messages due to better recovery, fewer include
116 stacks, and tuning verbose features such as 'a.k.a.' type printing.</li>
117 <li>
118 Able to recover and correct from misspelled type names at the begging of statements. For example, Clang now emits:
119 <code>t.c:6:3: error: use of undeclared identifier 'integer'; did you mean
120'Integer'?
121 integer *i = 0;
122 ^~~~~~~
123 Integer
124t.c:1:13: note: 'Integer' declared here
125typedef int Integer;
126 ^</code>
127 </li>
128 <li>Expanded typo correction to (among other improvements) look across
129 namespaces and suggest namespace qualifiers in addition to misspellings of the
130 identifier itself.</li>
131 <li>More rich macro expansion backtraces and some (limited) fix-it hints when
132 diagnostics stem from macro arguments.</li>
Chandler Carruth2f376852011-11-28 22:54:33 +0000[diff] [blame^]133 <li>Many new warnings have been added to catch common, bug-prone code
134 patterns.</li>
135 <li>Uninitialized values Clang warning was rewritten to be more accurate,
136 faster, and able to differentiate between the <em>possibility</em> of an
137 uninitialized use and the <em>certainty</em> of an uninitialized use.</li>
Chandler Carruth58f2cbc2011-11-28 22:34:59 +0000[diff] [blame]138</ul>
139
Chandler Carruth9a167122011-11-28 22:43:32 +0000[diff] [blame]140<h4 id="libclang">This release saw significant improvements to <code>libclang</code></h4>
141<ul>
142 <li>A broader set of the <code>libclang</code> API is exposed in the Python
143 bindings.</li>
144 <li>Much more of the Clang AST is exposed through <code>libclang</code>'s APIs
145 and cursors.</li>
146 <li>Cursors can now walk more effectively through macros, especially arguments
147 to function-style macros, and resolve to the underlying AST.</li>
148 <li>Improved code completion surrounding macros, macro arguments, and
149 token pasting.</li>
150 <li>Improved code completion for in-class member functions.</li>
151 <li>Crash recovery for <code>libclang</code> clients.</li>
152 <!-- Doug or Ted may want to flesh this out if there are relevant details I'm
153 glossing over... -->
154</ul>
155
Chandler Carruthb882a1d2011-11-28 21:56:30 +0000[diff] [blame]156<h4 id="driver">The Clang GCC-compatible command-line driver improved dramatically</h4>
157A great deal of work went into the GCC-compatible driver for the 3.0 release
158making it support more operating systems, emulate GCC behavior more accurately,
159and support a much broader range of Linux distributions out of the box.
160<ul>
161 <li>More accurate support for hardware architecture pre-defined macros (e.g.,
162 __i686__).</li>
163 <li>Robust library and header search paths for the vast majority of x86 and
164 x86-64 Linux distributions.</li>
165 <li>Improved support for newer Darwin platforms.</li>
166 <li>Partial support for <code>--sysroot=...</code> based cross-compiling on
167 Linux (and similar) host systems.</li>
168 <li>Improved support for locating and using libcxx when installed, especially
169 on Darwin.</li>
170 <!-- There are likely more Darwin-specific improvements to mention here? -->
171 <!-- What support was added for FreeBSD? NetBSD? Anything noteworthy? -->
Chandler Carruth2f376852011-11-28 22:54:33 +0000[diff] [blame^]172 <li>Automatic detection of Clang crashes in the driver and preparation of
173 reproduction steps for filing bug reports.</li><!-- Chad, feel free to add
174 more details here. -->
Chandler Carruthb882a1d2011-11-28 21:56:30 +0000[diff] [blame]175</ul>
176
Chandler Carruthc6f2af32011-11-28 19:17:25 +0000[diff] [blame]177<h4 id="ppcallbacks">Expanded support for instrumenting the preprocessor through
178 callbacks</h4>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]179Several enhancements were made to the <code>PPCallbacks</code> interface to
180expand the information available to tools and library users of Clang that wish
181to introspect the preprocessing.
Chandler Carruthc6f2af32011-11-28 19:17:25 +0000[diff] [blame]182<ul>
183 <li>The exact text used between the <code>""</code>s or <code>&lt;&gt;</code>s is reported.</li>
184 <li>The header search path used to locate the header is reported.</li>
185 <li>Missing files during including headers reported.</li>
186 <li>The exact source range for expanded macros can be retrieved.</li>
187</ul>
188
Chandler Carrutha0df07d2011-11-28 22:17:58 +0000[diff] [blame]189<!--
190Need Peter and/or Tanya to flesh this out if we want it in 3.0's notes.. The
191state isn't clear just from documentation or commit logs.
192
193<h4 id="opencl">Initial work to support compiling OpenCL with Clang</h4>
194Clang has some (limited) support for compiling OpenCL.
195-->
196
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]197<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
198<h3 id="cchanges">C Language Changes in Clang</h3>
199<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
200
Richard Smith62d730f2011-11-28 22:48:25 +0000[diff] [blame]201<h4 id="c1xchanges">C1X Feature Support</h4>
202
203<p>Clang 3.0 adds support for the
204<a href="http://clang.llvm.org/docs/LanguageExtensions.html#c1x">
205<code>_Alignas</code>, <code>_Generic</code>, and <code>_Static_assert</code>
206keywords</a>, drafted for inclusion in the next C standard, which is
207provisionally known as C1X. Use <code>-std=c1x</code> or <code>-std=gnu1x</code>
208to enable support for the new language standard. These features are
209backwards-compatible and are available as an extension in all language
210modes.</p>
211
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]212<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
213<h3 id="cxxchanges">C++ Language Changes in Clang</h3>
214<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
215
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]216<h4 id="cxx11changes">C++11 Feature Support</h4>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]217<p>Clang 3.0 adds support for
218<a href="http://clang.llvm.org/cxx_status.html#cxx11">more of the language
219features</a> added in the latest ISO C++ standard, C++11. Use
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]220<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]221features. The following are now considered to be of production quality:
222<ul>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]223 <li>Range-based <code>for</code> loops</li>
224 <li>Alias declarations (a new syntax for <code>typedef</code> declarations),
225 including their <code>template</code> forms</li>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]226 <li>Specifying default values for class data members within a class
227 definition</li>
228 <li>Constructors delegating to other constructors of the same class</li>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]229 <li>The <code>override</code> context-sensitive keyword for virtual member
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]230 function declarations</li>
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]231 <li>Explicitly generating default function definitions with
232 <code>= default</code></li>
233 <li>The <code>nullptr</code> keyword, and the corresponding type</li>
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]234 <li>Raw string literals with arbitary delimiters (for instance,
Chandler Carruthf16d7252011-11-28 21:47:51 +0000[diff] [blame]235 <code>R"delim(str"ing)delim"</code>)</li>
236 <li>Unicode string literals (for instance, <code>U"\u1234"</code>) and the
237 <code>char16_t</code> and <code>char32_t</code> built-in types
238 <li><code>noexcept</code> expressions and the <code>noexcept</code> specifier
239 on function declarations</li>
240 <li><code>alignof</code> expressions and the <code>alignas</code> specifier on
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]241 variable declarations</li>
242 <li>A full set of <a href="http://clang.llvm.org/docs/LanguageExtensions.html#checking_type_traits">type traits</a>,
243 sufficient to support C++11 standard libraries</li>
244</ul>
Chandler Carruthbc02a042011-11-28 21:55:34 +0000[diff] [blame]245All warning and language selection flags which previously accepted
246<code>c++0x</code> now accept <code>c++11</code>. The old <code>c++0x</code>
247form remains as an alias.
Richard Smith855746b2011-11-28 20:02:05 +0000[diff] [blame]248
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]249<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
250<h3 id="objcchanges">Objective-C Language Changes in Clang</h3>
251<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
252
253<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
254<h3 id="apichanges">Internal API Changes</h3>
255<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
256
Chandler Carruthc4dbffa2011-11-28 18:55:47 +0000[diff] [blame]257These are major API changes that have happened since the 2.9 release of Clang.
258If upgrading an external codebase that uses Clang as a library, this section
259should help get you past the largest hurdles of upgrading.
260
Chandler Carruth7d727b72011-11-28 19:06:34 +0000[diff] [blame]261<h4 id="macroexpansion">Switched terminology from "instantiation" to "expansion"
262 for macros</h4>
263A great deal of comments and code changes fell out of this, but also every API
264relating to macros with the word "instantiation" (or some variant thereof) was
265renamed. An incomplete list of the most note-worthy ones is here:
266<ul>
267 <li><code>MacroInstantiation</code> became <code>MacroExpansion</code></li>
268 <li><code>SourceManager::getInstantiationLoc</code> became
269 <code>SourceManager::getExpansionLoc</code></li>
270 <li><code>SourceManager::getInstantiationRange</code> became
271 <code>SourceManager::getExpansionRange</code></li>
272 <li><code>SourceManager::getImmediateInstantiationRange</code> became
273 <code>SourceManager::getImmediateExpansionRange</code></li>
274 <li><code>SourceManager::getDecomposedInstantiationLoc</code> became
275 <code>SourceManager::getDecomposedExpansionLoc</code></li>
276 <li><code>SourceManager::getInstantiationColumnNumber</code> became
277 <code>SourceManager::getExpansionColumnNumber</code></li>
278 <li><code>SourceManager::getInstantiationLineNumber</code> became
279 <code>SourceManager::getExpansionLineNumber</code></li>
280 <!-- TODO: Make this more complete! -->
281</ul>
282
Chandler Carruthc4dbffa2011-11-28 18:55:47 +0000[diff] [blame]283<h4 id="diagnosticrename">Diagnostic class names were shuffled</h4>
284<ul>
285 <li><code>Diagnostic</code> became <code>DiagnosticEngine</code></li>
286 <li><code>DiagnosticClient</code> became <code>DiagnosticConsumer</code></li>
287 <li><code>DiagnosticInfo</code> became <code>Diagnostic</code></li>
288</ul>
289Subclasses of <code>DiagnosticConsumer</code> were also then renamed to end with
290<code>Consumer</code>.
291
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]292<!-- ======================================================================= -->
293<h2 id="knownproblems">Significant Known Problems</h2>
294<!-- ======================================================================= -->
295
296<!-- ======================================================================= -->
297<h2 id="additionalinfo">Additional Information</h2>
298<!-- ======================================================================= -->
299
300<p>A wide variety of additional information is available on the
301<a href="http://clang.llvm.org/">Clang web page</a>. The web page contains
302versions of the API documentation which are up-to-date with the Subversion
303version of the source code. You can access versions of these documents specific
304to this release by going into the "<tt>clang/doc/</tt>" directory in the Clang
305tree.</p>
306
307<p>If you have any questions or comments about Clang, please feel free to
308contact us via the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">
309mailing list</a>.</p>
310
Chandler Carruth59abf062011-11-28 22:12:44 +0000[diff] [blame]311
312<!-- ======================================================================= -->
313<!-- Likely 3.1 release notes -->
314<!-- ======================================================================= -->
315<!--
316This is just a section to hold things that have already gotten started and
317should likely pick up proper release notes in 3.1.
318
319- C1X and C++11 atomics infrastructure and support
320- CUDA support?
321
322-->
323
Chandler Carruthc00c0c32011-11-28 07:16:19 +0000[diff] [blame]324</body>
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