Make createObjectFile's signature a bit less error prone.

This will be better with c++11, but right now file_magic converts to bool,
which makes the api really easy to misuse.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200357 91177308-0d34-0410-b5e6-96231b3b80d8
MC: Clean up error paths in AsmParser::parseMacroArgument

Use an RAII object Instead of inserting a call to
AsmLexer::setSkipSpace(true) in all error paths.

No functional change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200358 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unnecessary call to pthread_mutexattr_setpshared()

The default value of this attribute is PTHREAD_PROCESS_PRIVATE, so
there's no point in calling pthread_mutexattr_setpshared() to set
that.

See: http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutexattr_getpshared.html

This removes some ifdefs that tend to need to be extended for other
platforms (e.g. for NaCl).

Note that this call was in the first implementation of Mutex, added in
r22403, so it doesn't appear to have been added in response to a
performance problem.

Differential Revision: http://llvm-reviews.chandlerc.com/D2633

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200360 91177308-0d34-0410-b5e6-96231b3b80d8
[ARM] Remove superfluous inline asm mode switch test

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200361 91177308-0d34-0410-b5e6-96231b3b80d8