docs/ReleaseNotes.rst - fp2-dev/platform/external/clang - Gitiles

 =====================================
 Clang 3.4 (In-Progress) Release Notes
 =====================================

 .. contents::
    :local:
    :depth: 2

 Introduction
 ============

 This document contains the release notes for the Clang C/C++/Objective-C
 frontend, part of the LLVM Compiler Infrastructure, release 3.4. 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 3.4?
 ========================

 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.

 Last release which will build as C++98
 --------------------------------------

 This is expected to be the last release of Clang which compiles using a C++98
 toolchain. We expect to start using some C++11 features in Clang starting after
 this release. That said, we are committed to supporting a reasonable set of
 modern C++ toolchains as the host compiler on all of the platforms. This will
 at least include Visual Studio 2012 on Windows, and Clang 3.1 or GCC 4.7.x on
 Mac and Linux. The final set of compilers (and the C++11 features they support)
 is not set in stone, but we wanted users of Clang to have a heads up that the
 next release will involve a substantial change in the host toolchain
 requirements.

 Note that this change is part of a change for the entire LLVM project, not just
 Clang.

 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 3.3 release include:

 - -Wheader-guard warns on mismatches between the #ifndef and #define lines
   in a header guard.
 - -Wlogical-not-parentheses warns when a logical not ('!') only applies to the
   left-hand side of a comparison.  This warning is part of -Wparentheses.
 - Boolean increment, a deprecated feature, has own warning flag
   -Wdeprecated-increment-bool, and is still part of -Wdeprecated.
 - Clang errors on builtin enum increments and decrements.
 - -Wloop-analysis now warns on for-loops which have the same increment or
   decrement in the loop header as the last statement in the loop.
 - -Wuninitialized now performs checking across field initializers to detect
   when one field in used uninitialized in another field initialization.
 - Clang can detect initializer list use inside a macro and suggest parentheses
   if possible to fix.
 - Many improvements to Clang's typo correction facilities, such as:
   + Adding global namespace qualifiers so that corrections can refer to shadowed
     or otherwise ambiguous or unreachable namespaces.
   + Including accessible class members in the set of typo correction candidates,
     so that corrections requiring a class name in the name specifier are now
     possible.
   + Allowing typo corrections that involve removing a name specifier.
   + In some situations, correcting function names when a function was given the
     wrong number of arguments, including situations where the original function
     name was correct but was shadowed by a lexically closer function with the
     same name yet took a different number of arguments.
   + Offering typo suggestions for 'using' declarations.
   + Providing better diagnostics and fixit suggestions in more situations when
     a '->' was used instead of '.' or vice versa.
   + Providing more relevant suggestions for typos followed by '.' or '='.
   + Various performance improvements when searching for typo correction
     candidates.

 New Compiler Flags
 ------------------

 - Clang no longer special cases -O4 to enable lto. Explicitly pass -flto to
   enable it.
 - Clang no longer fails on >= -O5. Uses -O3 instead.
 - Command line "clang -O3 -flto a.c -c" and "clang -emit-llvm a.c -c"
   are no longer equivalent.
 - Clang now errors on unknown -m flags (``-munknown-to-clang``),
   unknown -f flags (``-funknown-to-clang``) and unknown
   options (``-what-is-this``).

 C Language Changes in Clang
 ---------------------------

 - Added new checked arithmetic builtins for security critical applications.

 C11 Feature Support
 ^^^^^^^^^^^^^^^^^^^

 ...

 C++ Language Changes in Clang
 -----------------------------

 - Fixed an ABI regression, introduced in Clang 3.2, which affected
   member offsets for classes inheriting from certain classes with tail padding.
   See PR16537.

 - ...

 C++11 Feature Support
 ^^^^^^^^^^^^^^^^^^^^^

 ...

 Objective-C Language Changes in Clang
 -------------------------------------

 ...

 OpenCL C Language Changes in Clang
 ----------------------------------

 - OpenCL C "long" now always has a size of 64 bit, and all OpenCL C
   types are aligned as specified in the OpenCL C standard. Also,
   "char" is now always signed.

 Internal API Changes
 --------------------

 These are major API changes that have happened since the 3.3 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.

 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
 --------

 ...

 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.

 Windows Support
 ---------------

 - `clang-cl <UsersManual.html#clang-cl>` provides a new driver mode that is
   designed for compatibility with Visual Studio's compiler, cl.exe. This driver
   mode makes Clang accept the same kind of command-line options as cl.exe. The
   installer will attempt to expose clang-cl in any Visual Studio installations
   on the system as a Platform Toolset, e.g. "LLVM-vs2012". clang-cl targets the
   Microsoft ABI by default. Please note that this driver mode and compatibility
   with the MS ABI is highly experimental.

 Core Analysis Improvements
 ==========================

 - ...

 New Issues Found
 ================

 - ...

 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>`_.
	=====================================
	Clang 3.4 (In-Progress) Release Notes
	=====================================

	.. contents::
	:local:
	:depth: 2

	Introduction
	============

	This document contains the release notes for the Clang C/C++/Objective-C
	frontend, part of the LLVM Compiler Infrastructure, release 3.4. 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 3.4?
	========================

	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.

	Last release which will build as C++98
	--------------------------------------

	This is expected to be the last release of Clang which compiles using a C++98
	toolchain. We expect to start using some C++11 features in Clang starting after
	this release. That said, we are committed to supporting a reasonable set of
	modern C++ toolchains as the host compiler on all of the platforms. This will
	at least include Visual Studio 2012 on Windows, and Clang 3.1 or GCC 4.7.x on
	Mac and Linux. The final set of compilers (and the C++11 features they support)
	is not set in stone, but we wanted users of Clang to have a heads up that the
	next release will involve a substantial change in the host toolchain
	requirements.

	Note that this change is part of a change for the entire LLVM project, not just
	Clang.

	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 3.3 release include:

	- -Wheader-guard warns on mismatches between the #ifndef and #define lines
	in a header guard.
	- -Wlogical-not-parentheses warns when a logical not ('!') only applies to the
	left-hand side of a comparison. This warning is part of -Wparentheses.
	- Boolean increment, a deprecated feature, has own warning flag
	-Wdeprecated-increment-bool, and is still part of -Wdeprecated.
	- Clang errors on builtin enum increments and decrements.
	- -Wloop-analysis now warns on for-loops which have the same increment or
	decrement in the loop header as the last statement in the loop.
	- -Wuninitialized now performs checking across field initializers to detect
	when one field in used uninitialized in another field initialization.
	- Clang can detect initializer list use inside a macro and suggest parentheses
	if possible to fix.
	- Many improvements to Clang's typo correction facilities, such as:
	+ Adding global namespace qualifiers so that corrections can refer to shadowed
	or otherwise ambiguous or unreachable namespaces.
	+ Including accessible class members in the set of typo correction candidates,
	so that corrections requiring a class name in the name specifier are now
	possible.
	+ Allowing typo corrections that involve removing a name specifier.
	+ In some situations, correcting function names when a function was given the
	wrong number of arguments, including situations where the original function
	name was correct but was shadowed by a lexically closer function with the
	same name yet took a different number of arguments.
	+ Offering typo suggestions for 'using' declarations.
	+ Providing better diagnostics and fixit suggestions in more situations when
	a '->' was used instead of '.' or vice versa.
	+ Providing more relevant suggestions for typos followed by '.' or '='.
	+ Various performance improvements when searching for typo correction
	candidates.

	New Compiler Flags
	------------------

	- Clang no longer special cases -O4 to enable lto. Explicitly pass -flto to
	enable it.
	- Clang no longer fails on >= -O5. Uses -O3 instead.
	- Command line "clang -O3 -flto a.c -c" and "clang -emit-llvm a.c -c"
	are no longer equivalent.
	- Clang now errors on unknown -m flags (``-munknown-to-clang``),
	unknown -f flags (``-funknown-to-clang``) and unknown
	options (``-what-is-this``).

	C Language Changes in Clang
	---------------------------

	- Added new checked arithmetic builtins for security critical applications.

	C11 Feature Support
	^^^^^^^^^^^^^^^^^^^

	...

	C++ Language Changes in Clang
	-----------------------------

	- Fixed an ABI regression, introduced in Clang 3.2, which affected
	member offsets for classes inheriting from certain classes with tail padding.
	See PR16537.

	- ...

	C++11 Feature Support
	^^^^^^^^^^^^^^^^^^^^^

	...

	Objective-C Language Changes in Clang
	-------------------------------------

	...

	OpenCL C Language Changes in Clang
	----------------------------------

	- OpenCL C "long" now always has a size of 64 bit, and all OpenCL C
	types are aligned as specified in the OpenCL C standard. Also,
	"char" is now always signed.

	Internal API Changes
	--------------------

	These are major API changes that have happened since the 3.3 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.

	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
	--------

	...

	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.

	Windows Support
	---------------

	- `clang-cl <UsersManual.html#clang-cl>` provides a new driver mode that is
	designed for compatibility with Visual Studio's compiler, cl.exe. This driver
	mode makes Clang accept the same kind of command-line options as cl.exe. The
	installer will attempt to expose clang-cl in any Visual Studio installations
	on the system as a Platform Toolset, e.g. "LLVM-vs2012". clang-cl targets the
	Microsoft ABI by default. Please note that this driver mode and compatibility
	with the MS ABI is highly experimental.

	Core Analysis Improvements
	==========================

	- ...

	New Issues Found
	================

	- ...

	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>`_.