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| <h1>Clang 3.0 Release Notes</h1> |
| |
| <img align=right src="http://llvm.org/img/DragonSmall.png" |
| width="136" height="136" alt="LLVM Dragon Logo"> |
| |
| <ul> |
| <li><a href="#intro">Introduction</a></li> |
| <li><a href="#whatsnew">What's New in Clang 3.0?</a> |
| <ul> |
| <li><a href="#majorfeatures">Major New Features</a></li> |
| <li><a href="#cchanges">C Language Changes</a></li> |
| <li><a href="#cxxhanges">C++ Language Changes</a></li> |
| <li><a href="#objchanges">Objective-C Language Changes</a></li> |
| <li><a href="#apichanges">Internal API Changes</a></li> |
| </ul> |
| </li> |
| <li><a href="#knownproblems">Known Problems</a></li> |
| <li><a href="#additionalinfo">Additional Information</a></li> |
| </ul> |
| |
| <div class="doc_author"> |
| <p>Written by the <a href="http://llvm.org/">LLVM Team</a></p> |
| </div> |
| |
| <!-- |
| <h1 style="color:red">These are in-progress notes for the upcoming LLVM 3.0 |
| release.<br> |
| You may prefer the |
| <a href="http://llvm.org/releases/2.9/docs/ReleaseNotes.html">LLVM 2.9 |
| Release Notes</a>.</h1> |
| --> |
| |
| <!-- ======================================================================= --> |
| <h2 id="intro">Introduction</h2> |
| <!-- ======================================================================= --> |
| |
| <p>This document contains the release notes for the Clang C/C++/Objective-C |
| frontend, part of the LLVM Compiler Infrastructure, release 3.0. 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 <a href ="http;//llvm.org/docs/ReleaseNotes.html">the LLVM |
| documentation</a>. All LLVM releases may be downloaded from the |
| <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p> |
| |
| <p>For more information about Clang or LLVM, including information about the |
| latest release, please check out the main please see the |
| <a href="http://clang.llvm.org">Clang Web Site</a> or the |
| <a href="http://llvm.org">LLVM Web Site</a>. |
| |
| <p>Note that if you are reading this file from a Subversion checkout or the main |
| Clang web page, this document applies to the <i>next</i> release, not the |
| current one. To see the release notes for a specific release, please see the |
| <a href="http://llvm.org/releases/">releases page</a>.</p> |
| |
| <!-- ======================================================================= --> |
| <h2 id="whatsnew">What's New in Clang 3.0?</h2> |
| <!-- ======================================================================= --> |
| |
| <p>Some of the major new features and improvements to Clang are listed here. |
| Generic improvements to Clang as a whole or two its underlying infrastructure |
| are described first, followed by language-specific sections with improvements to |
| Clang's support for those languages.</p> |
| |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| <h3 id="majorfeatures">Major New Features</h3> |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| |
| <h4 id="notes">Unorganized Notes</h4> |
| <p>These are completely random notes as I'm organizing my thoughts and reviewing |
| the history. Anything still here needs to be distilled and turned into proper |
| prose in a section of its own. When doing that, delete the notes.</p> |
| <ul> |
| <li>OS Availability attribute -- r128127</li> |
| <li>GNU ObjectiveC Runtime support -- David Chisnall</li> |
| <li>Improved AST support for partially constructed nodes and incomplete |
| information for LLDB and other clients which dynamically build AST nodes.</li> |
| <li>Memory reduction -- initializers, macro expansions, source locations, |
| etc.</li> |
| <li>Thread Safety attributes and correctness analysis added to Clang.</li> |
| <li>Major improvements to the interactions between serializing and |
| deserializing the AST and the preprocessor -- argiris</li> |
| </ul> |
| |
| <h4 id="diagnostics">A multitude of improvements to Clang's diagnostics</h4> |
| Clang's diagnostics are constantly being improved to catch more issues, explain |
| them more clearly, and provide more accurate source information about them. |
| A few improvements since the 2.9 release that have a particularly high impact: |
| <ul> |
| <li>Substantially shorter messages due to better recovery, fewer include |
| stacks, and tuning verbose features such as 'a.k.a.' type printing.</li> |
| <li> |
| Able to recover and correct from misspelled type names at the begging of statements. For example, Clang now emits: |
| <pre><b>t.c:6:3: <span class="error">error:</span> use of undeclared identifier 'integer'; did you mean 'Integer'?</b> |
| integer *i = 0; |
| <span class="caret">^~~~~~~</span> |
| Integer |
| <b>t.c:1:13: note:</b> 'Integer' declared here |
| typedef int Integer; |
| <span class="caret">^</span></pre> |
| </li> |
| <li>Expanded typo correction to (among other improvements) look across |
| namespaces and suggest namespace qualifiers in addition to misspellings of the |
| identifier itself.</li> |
| <li>More rich macro expansion backtraces and some (limited) fix-it hints when |
| diagnostics stem from macro arguments.</li> |
| <li>Many new warnings have been added to catch common, bug-prone code |
| patterns.</li> |
| <li>Uninitialized values Clang warning was rewritten to be more accurate, |
| faster, and able to differentiate between the <em>possibility</em> of an |
| uninitialized use and the <em>certainty</em> of an uninitialized use.</li> |
| </ul> |
| |
| <h4 id="libclang">This release saw significant improvements to <code>libclang</code></h4> |
| <ul> |
| <li>A broader set of the <code>libclang</code> API is exposed in the Python |
| bindings.</li> |
| <li>Much more of the Clang AST is exposed through <code>libclang</code>'s APIs |
| and cursors.</li> |
| <li>Cursors can now walk more effectively through macros, especially arguments |
| to function-style macros, and resolve to the underlying AST.</li> |
| <li>Improved code completion surrounding macros, macro arguments, and |
| token pasting.</li> |
| <li>Improved code completion for in-class member functions.</li> |
| <li>Crash recovery for <code>libclang</code> clients.</li> |
| <!-- Doug or Ted may want to flesh this out if there are relevant details I'm |
| glossing over... --> |
| </ul> |
| |
| <h4 id="driver">The Clang GCC-compatible command-line driver improved dramatically</h4> |
| A great deal of work went into the GCC-compatible driver for the 3.0 release |
| making it support more operating systems, emulate GCC behavior more accurately, |
| and support a much broader range of Linux distributions out of the box. |
| <ul> |
| <li>More accurate support for hardware architecture pre-defined macros (e.g., |
| __i686__).</li> |
| <li>Robust library and header search paths for the vast majority of x86 and |
| x86-64 Linux distributions.</li> |
| <li>Improved support for newer Darwin platforms.</li> |
| <li>Partial support for <code>--sysroot=...</code> based cross-compiling on |
| Linux (and similar) host systems.</li> |
| <li>Improved support for locating and using libcxx when installed, especially |
| on Darwin.</li> |
| <!-- There are likely more Darwin-specific improvements to mention here? --> |
| <!-- What support was added for FreeBSD? NetBSD? Anything noteworthy? --> |
| <li>Automatic detection of Clang crashes in the driver and preparation of |
| reproduction steps for filing bug reports.</li><!-- Chad, feel free to add |
| more details here. --> |
| </ul> |
| |
| <h4 id="ppcallbacks">Expanded support for instrumenting the preprocessor through |
| callbacks</h4> |
| Several enhancements were made to the <code>PPCallbacks</code> interface to |
| expand the information available to tools and library users of Clang that wish |
| to introspect the preprocessing. |
| <ul> |
| <li>The exact text used between the <code>""</code>s or <code><></code>s is reported.</li> |
| <li>The header search path used to locate the header is reported.</li> |
| <li>Missing files during including headers reported.</li> |
| <li>The exact source range for expanded macros can be retrieved.</li> |
| </ul> |
| |
| <h4 id="windows">Clang is building and tested regularly on Windows and can |
| compile limited subsets of code on Windows</h4> |
| Clang is regularly built and tested on a variety of Windows platforms including |
| MinGW 32-bit and 64-bit, Cygwin, and natively with MSVC. In addition, Clang can |
| be used as a compiler in a few Windows contexts. |
| <ul> |
| <li>Normal compilation supported for the MinGW target platform, in both 32-bit |
| and 64-bit, and the Cygwin target platform.</li> |
| <li>Parsing and AST support for Windows Structured Exception Handling.</li> |
| <li>New -fms-compatibility flag to handle MSVC constructs that could change |
| the meaning of an otherwise well formed program</li> |
| <li>clang can now parse all the MSVC 2010 standard C++ header files |
| in the nominal case, (still need to specifiy -nobuiltininc for some headers).</li> |
| <li>Improved support for MFC code parsing, (still a work in progress).</li> |
| <li>Add support for function template specialization at class scope (-fms-extensions mode).</li> |
| <li>Add support for Microsoft __if_exists/__if_not_exists statements (-fms-extensions mode).</li> |
| </ul> |
| |
| <!-- |
| Need Peter and/or Tanya to flesh this out if we want it in 3.0's notes.. The |
| state isn't clear just from documentation or commit logs. |
| |
| <h4 id="opencl">Initial work to support compiling OpenCL with Clang</h4> |
| Clang has some (limited) support for compiling OpenCL. |
| --> |
| |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| <h3 id="cchanges">C Language Changes in Clang</h3> |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| |
| <h4 id="c1xchanges">C1X Feature Support</h4> |
| |
| <p>Clang 3.0 adds support for the |
| <a href="http://clang.llvm.org/docs/LanguageExtensions.html#c1x"> |
| <code>_Alignas</code>, <code>_Generic</code>, and <code>_Static_assert</code> |
| keywords</a>, drafted for inclusion in the next C standard, which is |
| provisionally known as C1X. Use <code>-std=c1x</code> or <code>-std=gnu1x</code> |
| to enable support for the new language standard. These features are |
| backwards-compatible and are available as an extension in all language |
| modes.</p> |
| |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| <h3 id="cxxchanges">C++ Language Changes in Clang</h3> |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| |
| <h4 id="cxx11changes">C++11 Feature Support</h4> |
| <p>Clang 3.0 adds support for |
| <a href="http://clang.llvm.org/cxx_status.html#cxx11">more of the language |
| features</a> added in the latest ISO C++ standard, |
| <a href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=50372">C++ 2011</a>. |
| Use <code>-std=c++11</code> or <code>-std=gnu++11</code> to enable support for |
| these features. The following are now considered to be of production quality: |
| <ul> |
| <li>Range-based <code>for</code> loops</li> |
| <li>Alias declarations (a new syntax for <code>typedef</code> declarations), |
| including their <code>template</code> forms</li> |
| <li>Specifying default values for class data members within a class |
| definition</li> |
| <li>Constructors delegating to other constructors of the same class</li> |
| <li>The <code>override</code> context-sensitive keyword for virtual member |
| function declarations</li> |
| <li>Explicitly generating default function definitions with |
| <code>= default</code></li> |
| <li>The <code>nullptr</code> keyword, and the corresponding type</li> |
| <li>Raw string literals with arbitary delimiters (for instance, |
| <code>R"delim(str"ing)delim"</code>)</li> |
| <li>Unicode string literals (for instance, <code>U"\u1234"</code>) and the |
| <code>char16_t</code> and <code>char32_t</code> built-in types |
| <li><code>noexcept</code> expressions and the <code>noexcept</code> specifier |
| on function declarations</li> |
| <li><code>alignof</code> expressions and the <code>alignas</code> specifier on |
| variable declarations</li> |
| <li>A full set of <a href="http://clang.llvm.org/docs/LanguageExtensions.html#checking_type_traits">type traits</a>, |
| sufficient to support C++11 standard libraries</li> |
| </ul> |
| All warning and language selection flags which previously accepted |
| <code>c++0x</code> now accept <code>c++11</code>. The old <code>c++0x</code> |
| form remains as an alias. |
| |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| <h3 id="objcchanges">Objective-C Language Changes in Clang</h3> |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| Clang 3.0 introduces several new Objective-C language features and improvements. |
| |
| <h4 id="objc_arc">Objective-C Automatic Reference Counting</h4> |
| <!-- This is really just a stub for John to flesh out regarding ARC. --> |
| ARC provides automated memory management for Objective-C programs that is |
| compatible with existing retain/release code. ARC is carefully built to |
| be a reliable programming model that errs on the side of producing a |
| compiler error instead of silently producing a runtime memory problem. |
| ARC automates Objective-C objects, not malloc data, file descriptors, |
| CoreFoundation datatypes or anything else. For more details, see the |
| <a href="http://clang.llvm.org/docs/AutomaticReferenceCounting.html">full specification</a>. |
| |
| <h4 id="objc_instancetype">Objective-C Related Result Types / Instance |
| Types</h4> |
| Allows declaring new methods which follow the Cocoa conventions for methods |
| such as <code>init</code> which always return objects that are an instance of |
| the receiving class's type. For more details, see the |
| <a href="http://clang.llvm.org/docs/LanguageExtensions.html#objc_instancetype">language extension documentation</a>. |
| |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| <h3 id="apichanges">Internal API Changes</h3> |
| <!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = --> |
| |
| These are major API changes that have happened since the 2.9 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. |
| |
| <h4 id="macroexpansion">Switched terminology from "instantiation" to "expansion" |
| for macros</h4> |
| A great deal of comments and code changes fell out of this, but also every API |
| relating to macros with the word "instantiation" (or some variant thereof) was |
| renamed. An incomplete list of the most note-worthy ones is here: |
| <ul> |
| <li><code>MacroInstantiation</code> became <code>MacroExpansion</code></li> |
| <li><code>SourceManager::getInstantiationLoc</code> became |
| <code>SourceManager::getExpansionLoc</code></li> |
| <li><code>SourceManager::getInstantiationRange</code> became |
| <code>SourceManager::getExpansionRange</code></li> |
| <li><code>SourceManager::getImmediateInstantiationRange</code> became |
| <code>SourceManager::getImmediateExpansionRange</code></li> |
| <li><code>SourceManager::getDecomposedInstantiationLoc</code> became |
| <code>SourceManager::getDecomposedExpansionLoc</code></li> |
| <li><code>SourceManager::getInstantiationColumnNumber</code> became |
| <code>SourceManager::getExpansionColumnNumber</code></li> |
| <li><code>SourceManager::getInstantiationLineNumber</code> became |
| <code>SourceManager::getExpansionLineNumber</code></li> |
| <!-- TODO: Make this more complete! --> |
| </ul> |
| |
| <h4 id="diagnosticrename">Diagnostic class names were shuffled</h4> |
| <ul> |
| <li><code>Diagnostic</code> became <code>DiagnosticEngine</code></li> |
| <li><code>DiagnosticClient</code> became <code>DiagnosticConsumer</code></li> |
| <li><code>DiagnosticInfo</code> became <code>Diagnostic</code></li> |
| </ul> |
| Subclasses of <code>DiagnosticConsumer</code> were also then renamed to end with |
| <code>Consumer</code>. |
| |
| <!-- ======================================================================= --> |
| <h2 id="knownproblems">Significant Known Problems</h2> |
| <!-- ======================================================================= --> |
| |
| <!-- ======================================================================= --> |
| <h2 id="additionalinfo">Additional Information</h2> |
| <!-- ======================================================================= --> |
| |
| <p>A wide variety of additional information is available on the |
| <a href="http://clang.llvm.org/">Clang web page</a>. 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 "<tt>clang/doc/</tt>" directory in the Clang |
| tree.</p> |
| |
| <p>If you have any questions or comments about Clang, please feel free to |
| contact us via the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev"> |
| mailing list</a>.</p> |
| |
| |
| <!-- ======================================================================= --> |
| <!-- Likely 3.1 release notes --> |
| <!-- ======================================================================= --> |
| <!-- |
| This is just a section to hold things that have already gotten started and |
| should likely pick up proper release notes in 3.1. |
| |
| - C1X and C++11 atomics infrastructure and support |
| - CUDA support? |
| |
| --> |
| |
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