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Sylvestre Ledru authoredSummary: Currently with clang: $ clang -O20 foo.c error: invalid value '20' in '-O20' With the patch: $ clang -O20 foo.c warning: optimization level '-O20' is unsupported; using '-O3' instead. 1 warning generated. This matches the gcc behavior (with a warning added) Pass all tests: Testing: 0 .. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. Testing Time: 94.14s Expected Passes : 6721 Expected Failures : 20 Unsupported Tests : 17 (which was not the case of http://llvm-reviews.chandlerc.com/D2125) Differential Revision: http://llvm-reviews.chandlerc.com/D2212 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195009 91177308-0d34-0410-b5e6-96231b3b80d8
Sylvestre Ledru authoredSummary: Currently with clang: $ clang -O20 foo.c error: invalid value '20' in '-O20' With the patch: $ clang -O20 foo.c warning: optimization level '-O20' is unsupported; using '-O3' instead. 1 warning generated. This matches the gcc behavior (with a warning added) Pass all tests: Testing: 0 .. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. Testing Time: 94.14s Expected Passes : 6721 Expected Failures : 20 Unsupported Tests : 17 (which was not the case of http://llvm-reviews.chandlerc.com/D2125) Differential Revision: http://llvm-reviews.chandlerc.com/D2212 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195009 91177308-0d34-0410-b5e6-96231b3b80d8
Clang 3.4 (In-Progress) Release Notes
Written by the LLVM Team
Warning
These are in-progress notes for the upcoming Clang 3.4 release. You may prefer the Clang 3.3 Release Notes.
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. All LLVM releases may be downloaded from the LLVM releases web site.
For more information about Clang or LLVM, including information about the latest release, please check out the main please see the Clang Web Site or the LLVM Web Site.
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.
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:
- ...
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.
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. 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.