forked from OSchip/llvm-project
Clear the clang release notes to make room for 3.6.
llvm-svn: 216293
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Rafael Espindola
parent
bd334e2f32
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af74250ec0
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@ -10,15 +10,15 @@ Written by the `LLVM Team <http://llvm.org/>`_
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.. warning::
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These are in-progress notes for the upcoming Clang 3.5 release. You may
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prefer the `Clang 3.4 Release Notes
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<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>`_.
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These are in-progress notes for the upcoming Clang 3.6 release. You may
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prefer the `Clang 3.5 Release Notes
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<http://llvm.org/releases/3.5/tools/clang/docs/ReleaseNotes.html>`_.
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Introduction
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============
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This document contains the release notes for the Clang C/C++/Objective-C
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frontend, part of the LLVM Compiler Infrastructure, release 3.5. Here we
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frontend, part of the LLVM Compiler Infrastructure, release 3.6. Here we
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describe the status of Clang in some detail, including major
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improvements from the previous release and new feature work. For the
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general LLVM release notes, see `the LLVM
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@ -36,7 +36,7 @@ main Clang web page, this document applies to the *next* release, not
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the current one. To see the release notes for a specific release, please
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see the `releases page <http://llvm.org/releases/>`_.
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What's New in Clang 3.5?
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What's New in Clang 3.6?
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========================
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Some of the major new features and improvements to Clang are listed
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@ -47,14 +47,7 @@ sections with improvements to Clang's support for those languages.
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Major New Features
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------------------
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- Clang uses the new MingW ABI
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GCC 4.7 changed the mingw ABI. Clang 3.4 and older use the GCC 4.6
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ABI. Clang 3.5 and newer use the GCC 4.7 abi.
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- The __has_attribute feature test is now target-aware. Older versions of Clang
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would return true when the attribute spelling was known, regardless of whether
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the attribute was available to the specific target. Clang now returns true
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only when the attribute pertains to the current compilation target.
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- A big one.
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Improvements to Clang's diagnostics
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@ -62,77 +55,25 @@ Improvements to Clang's diagnostics
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Clang's diagnostics are constantly being improved to catch more issues,
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explain them more clearly, and provide more accurate source information
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about them. The improvements since the 3.4 release include:
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- GCC compatibility: Clang displays a warning on unsupported gcc
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optimization flags instead of an error.
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about them. The improvements since the 3.5 release include:
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- ...
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New Compiler Flags
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------------------
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The integrated assembler is now turned on by default on ARM (and Thumb),
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so the use of the option `-fintegrated-as` is now redundant on those
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architectures. This is an important move to both *eat our own dog food*
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and to ease cross-compilation tremendously.
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The option ....
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We are aware of the problems that this may cause for code bases that
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rely on specific GNU syntax or extensions, and we're working towards
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getting them all fixed. Please, report bugs or feature requests if
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you find anything. In the meantime, use `-fno-integrated-as` to revert
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back the call to GNU assembler.
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In order to provide better diagnostics, the integrated assembler validates
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inline assembly when the integrated assembler is enabled. Because this is
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considered a feature of the compiler, it is controlled via the `fintegrated-as`
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and `fno-integrated-as` flags which enable and disable the integrated assembler
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respectively. `-integrated-as` and `-no-integrated-as` are now considered
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legacy flags (but are available as an alias to prevent breaking existing users),
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and users are encouraged to switch to the equivalent new feature flag.
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Deprecated flags `-faddress-sanitizer`, `-fthread-sanitizer`,
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`-fcatch-undefined-behavior` and `-fbounds-checking` were removed in favor of
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`-fsanitize=` family of flags.
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It is now possible to get optimization reports from the major transformation
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passes via three new flags: `-Rpass`, `-Rpass-missed` and `-Rpass-analysis`.
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These flags take a POSIX regular expression which indicates the name
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of the pass (or passes) that should emit optimization remarks.
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The option `-u` is forwarded to the linker on gnutools toolchains.
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New Pragmas in Clang
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-----------------------
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Loop optimization hints can be specified using the new `#pragma clang loop`
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directive just prior to the desired loop. The directive allows vectorization,
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interleaving, and unrolling to be enabled or disabled. Vector width as well
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as interleave and unrolling count can be manually specified. See language
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extensions for details.
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Clang now supports the `#pragma unroll` and `#pragma nounroll` directives to
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specify loop unrolling optimization hints. Placed just prior to the desired
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loop, `#pragma unroll` directs the loop unroller to attempt to fully unroll the
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loop. The pragma may also be specified with a positive integer parameter
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indicating the desired unroll count: `#pragma unroll _value_`. The unroll count
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parameter can be optionally enclosed in parentheses. The directive `#pragma
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nounroll` indicates that the loop should not be unrolled.
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Clang now supports the ...
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Windows Support
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---------------
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Clang's support for building native Windows programs, compatible with Visual
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C++, has improved significantly since the previous release. This includes
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correctly passing non-trivial objects by value, record layout, basic debug info,
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`Address Sanitizer <AddressSanitizer.html>`_ support, RTTI, name mangling,
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DLL attributes, and many many bug fixes. See
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`MSVC Compatibility <MSVCCompatibility.html>`_ for details.
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While still considered experimental, Clang's Windows support is good enough
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that Clang can self-host on Windows, and projects such as Chromium and Firefox
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have been built successfully using the
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`/fallback <UsersManual.html#the-fallback-option>`_ option.
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Clang's support for building native Windows programs ...
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C Language Changes in Clang
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@ -168,7 +109,7 @@ OpenCL C Language Changes in Clang
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Internal API Changes
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--------------------
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These are major API changes that have happened since the 3.4 release of
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These are major API changes that have happened since the 3.5 release of
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Clang. If upgrading an external codebase that uses Clang as a library,
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this section should help get you past the largest hurdles of upgrading.
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@ -182,16 +123,6 @@ libclang
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Static Analyzer
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---------------
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The `-analyzer-config` options are now passed from scan-build through to
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ccc-analyzer and then to Clang.
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With the option `-analyzer-config stable-report-filename=true`,
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instead of `report-XXXXXX.html`, scan-build/clang analyzer generate
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`report-<filename>-<function, method name>-<function position>-<id>.html`.
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(id = i++ for several issues found in the same function/method).
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List the function/method name in the index page of scan-build.
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...
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Core Analysis Improvements
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