llvm-project/clang
Craig Topper be4cbe8726 [X86] Add explicit alignment to __m128/__m128i/__m128d/etc. to allow matching of MSVC behavior with #pragma pack.
Summary:
With MSVC, #pragma pack is ignored when there is explicit alignment. This differs from gcc. Clang emulates this difference when compiling for Windows.

It appears that MSVC and its headers consider the __m128/__m128i/__m128d/etc. types to be explicitly aligned and ignores #pragma pack for them. Since we don't have explicit alignment on them in our headers, we don't match the MSVC behavior here.

This patch adds explicit alignment to match this behavior. I'm hoping this won't cause any problems when we're not emulating MSVC. But if someone knows of something that would be different we can swith to conditionally adding the alignment based on _MSC_VER.

I had to add explicitly unaligned types as well so we could use them in the loadu/storeu intrinsics which use __attribute__(__packed__). Using the now explicitly aligned types wouldn't produce align 1 accesses when targeting Windows.

Reviewers: rnk, erichkeane, spatel, RKSimon

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D57961

llvm-svn: 353555
2019-02-08 19:45:08 +00:00
..
INPUTS
bindings Fix python3 compability issue in clang binding 2019-01-24 10:34:44 +00:00
cmake Move the SMT API to LLVM 2019-02-07 03:19:45 +00:00
docs [ASTMatchers][NFC] Update comments on assorted `CXXMemberCallExpr` matchers. 2019-02-08 16:00:44 +00:00
examples Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
include [OPENMP]Delay emission of the error messages for the exceptions. 2019-02-08 18:02:25 +00:00
lib [X86] Add explicit alignment to __m128/__m128i/__m128d/etc. to allow matching of MSVC behavior with #pragma pack. 2019-02-08 19:45:08 +00:00
runtime [CMake] External compiler-rt-configure requires LLVMTestingSupport when including tests 2019-02-01 15:35:25 +00:00
test [X86] Add explicit alignment to __m128/__m128i/__m128d/etc. to allow matching of MSVC behavior with #pragma pack. 2019-02-08 19:45:08 +00:00
tools [OpenMP 5.0] Parsing/sema support for "omp declare mapper" directive. 2019-02-01 20:25:04 +00:00
unittests [Format/ObjC] Fix [foo bar]->baz formatting as lambda arrow 2019-02-08 15:55:18 +00:00
utils [analyzer] [testing] Inside CmpRuns.py output also print the filename of the first item in the path 2019-02-05 22:26:57 +00:00
www [analyzer] Document RetainCountChecker behavior and annotations 2019-02-05 22:27:10 +00:00
.arcconfig
.clang-format
.clang-tidy Disable tidy checks with too many hits 2019-02-01 11:20:13 +00:00
.gitignore Adjust documentation for git migration. 2019-01-29 16:37:27 +00:00
CMakeLists.txt Move the SMT API to LLVM 2019-02-07 03:19:45 +00:00
CODE_OWNERS.TXT Add myself as code owner for OpenBSD driver 2018-11-30 21:42:34 +00:00
INSTALL.txt
LICENSE.TXT Fix typos throughout the license files that somehow I and my reviewers 2019-01-21 09:52:34 +00:00
ModuleInfo.txt
NOTES.txt PTH-- Remove feature entirely- 2018-12-04 14:34:09 +00:00
README.txt

README.txt

//===----------------------------------------------------------------------===//
// C Language Family Front-end
//===----------------------------------------------------------------------===//

Welcome to Clang.  This is a compiler front-end for the C family of languages
(C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM
compiler infrastructure project.

Unlike many other compiler frontends, Clang is useful for a number of things
beyond just compiling code: we intend for Clang to be host to a number of
different source-level tools.  One example of this is the Clang Static Analyzer.

If you're interested in more (including how to build Clang) it is best to read
the relevant web sites.  Here are some pointers:

Information on Clang:             http://clang.llvm.org/
Building and using Clang:         http://clang.llvm.org/get_started.html
Clang Static Analyzer:            http://clang-analyzer.llvm.org/
Information on the LLVM project:  http://llvm.org/

If you have questions or comments about Clang, a great place to discuss them is
on the Clang development mailing list:
  http://lists.llvm.org/mailman/listinfo/cfe-dev

If you find a bug in Clang, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/