| ===================================== |
| Clang 3.3 (In-Progress) Release Notes |
| ===================================== |
| |
| .. contents:: |
| :local: |
| :depth: 2 |
| |
| Written by the `LLVM Team <http://llvm.org/>`_ |
| |
| .. warning:: |
| |
| These are in-progress notes for the upcoming Clang 3.3 release. You may |
| prefer the `Clang 3.2 Release Notes |
| <http://llvm.org/releases/3.2/docs/ClangReleaseNotes.html>`_. |
| |
| Introduction |
| ============ |
| |
| This document contains the release notes for the Clang C/C++/Objective-C |
| frontend, part of the LLVM Compiler Infrastructure, release 3.3. 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 `the LLVM |
| documentation <http://llvm.org/docs/ReleaseNotes.html>`_. All LLVM |
| releases may be downloaded from the `LLVM releases web |
| site <http://llvm.org/releases/>`_. |
| |
| For more information about Clang or LLVM, including information about |
| the latest release, please check out the main please see the `Clang Web |
| Site <http://clang.llvm.org>`_ or the `LLVM Web |
| Site <http://llvm.org>`_. |
| |
| Note that if you are reading this file from a Subversion checkout or the |
| main Clang web page, this document applies to the *next* release, not |
| the current one. To see the release notes for a specific release, please |
| see the `releases page <http://llvm.org/releases/>`_. |
| |
| What's New in Clang 3.3? |
| ======================== |
| |
| Some of the major new features and improvements to Clang are listed |
| here. Generic improvements to Clang as a whole or to its underlying |
| infrastructure are described first, followed by language-specific |
| sections with improvements to Clang's support for those languages. |
| |
| Major New Features |
| ------------------ |
| |
| Improvements to Clang's diagnostics |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| Clang's diagnostics are constantly being improved to catch more issues, |
| explain them more clearly, and provide more accurate source information |
| about them. The improvements since the 3.2 release include: |
| |
| - ... |
| |
| Extended Identifiers: Unicode Support and Universal Character Names |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| Clang 3.3 includes support for *extended identifiers* in C99 and C++. |
| This feature allows identifiers to contain certain Unicode characters, as |
| specified by the active language standard; these characters can be written |
| directly in the source file using the UTF-8 encoding, or referred to using |
| *universal character names* (``\u00E0``, ``\U000000E0``). |
| |
| New Compiler Flags |
| ------------------ |
| |
| - ... |
| |
| C Language Changes in Clang |
| --------------------------- |
| |
| C11 Feature Support |
| ^^^^^^^^^^^^^^^^^^^ |
| |
| ... |
| |
| C++ Language Changes in Clang |
| ----------------------------- |
| |
| - Clang now correctly implements language linkage for functions and variables. |
| This means that, for example, it is now possible to overload static functions |
| declared in an ``extern "C"`` context. For backwards compatibility, an alias |
| with the unmangled name is still emitted if it is the only one and has the |
| ``used`` attribute. |
| |
| C++11 Feature Support |
| ^^^^^^^^^^^^^^^^^^^^^ |
| |
| ... |
| |
| Objective-C Language Changes in Clang |
| ------------------------------------- |
| |
| ... |
| |
| Internal API Changes |
| -------------------- |
| |
| These are major API changes that have happened since the 3.2 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. |
| |
| Value Casting |
| ^^^^^^^^^^^^^ |
| |
| Certain type hierarchies (TypeLoc, CFGElement, ProgramPoint, and SVal) were |
| misusing the llvm::cast machinery to perform undefined operations. Their APIs |
| have been changed to use two member function templates that return values |
| instead of pointers or references - "T castAs" and "Optional<T> getAs" (in the |
| case of the TypeLoc hierarchy the latter is "T getAs" and you can use the |
| boolean testability of a TypeLoc (or its 'validity') to verify that the cast |
| succeeded). Essentially all previous 'cast' usage should be replaced with |
| 'castAs' and 'dyn_cast' should be replaced with 'getAs'. See r175462 for the |
| first example of such a change along with many examples of how code was |
| migrated to the new API. |
| |
| Storage Class |
| ^^^^^^^^^^^^^ |
| |
| For each variable and function Clang used to keep the storage class as written |
| in the source, the linkage and a semantic storage class. This was a bit |
| redundant and the semantic storage class has been removed. The method |
| getStorageClass now returns what is written in the source code for that decl. |
| |
| Wide Character Types |
| ^^^^^^^^^^^^^^^^^^^^ |
| |
| The ASTContext class now keeps track of two different types for wide character |
| types: WCharTy and WideCharTy. WCharTy represents the built-in wchar_t type |
| available in C++. WideCharTy is the type used for wide character literals; in |
| C++ it is the same as WCharTy, but in C99, where wchar_t is a typedef, it is an |
| integer type. |
| |
| ... |
| |
| libclang |
| -------- |
| |
| The clang_CXCursorSet_contains() function previously incorrectly returned 0 |
| if it contained a CXCursor, contrary to what the documentation stated. This |
| has been fixed so that the function returns a non-zero value if the set |
| contains a cursor. This is API breaking change, but matches the intended |
| original behavior. Moreover, this also fixes the issue of an invalid CXCursorSet |
| appearing to contain any CXCursor. |
| |
| Static Analyzer |
| --------------- |
| |
| The static analyzer (which contains additional code checking beyond compiler |
| warnings) has improved significantly in both in the core analysis engine and |
| also in the kinds of issues it can find. |
| |
| Core Analysis Improvements |
| ========================== |
| |
| - Support for interprocedural reasoning about constructors and destructors. |
| - New false positive suppression mechanisms that reduced the number of false null pointer dereference warnings due to interprocedural analysis. |
| - Major performance enhancements to speed up interprocedural analysis |
| |
| New Issues Found |
| ================ |
| |
| - New memory error checks such as use-after-free with C++ 'delete'. |
| - Detection of mismatched allocators and deallocators (e.g., using 'new' with 'free()', 'malloc()' with 'delete'). |
| - Additional checks for misuses of Apple Foundation framework collection APIs. |
| |
| Python Binding Changes |
| ---------------------- |
| |
| The following methods have been added: |
| |
| - ... |
| |
| Significant Known Problems |
| ========================== |
| |
| Additional Information |
| ====================== |
| |
| A wide variety of additional information is available on the `Clang web |
| page <http://clang.llvm.org/>`_. 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 "``clang/docs/``" directory in the Clang |
| tree. |
| |
| If you have any questions or comments about Clang, please feel free to |
| contact us via the `mailing |
| list <http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev>`_. |