[analyzer] Model getters of known-@synthesized Objective-C properties.

...by synthesizing their body to be "return self->_prop;", with an extra
nudge to RetainCountChecker to still treat the value as +0 if we have no
other information.

This doesn't handle weak properties, but that's mostly correct anyway,
since they can go to nil at any time. This also doesn't apply to properties
whose implementations we can't see, since they may not be backed by an
ivar at all. And finally, this doesn't handle properties of C++ class type,
because we can't invoke the copy constructor. (Sema has actually done this
work already, but the AST it synthesizes is one the analyzer doesn't quite
handle -- it has an rvalue DeclRefExpr.)

Modeling setters is likely to be more difficult (since it requires
handling strong/copy), but not impossible.

<rdar://problem/11956898>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198953 91177308-0d34-0410-b5e6-96231b3b80d8
Downgrade bogus ExtWarn on duplicate 'friend' specifier to a Warning, and add a
Warning for a duplicate 'constexpr' specifier.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198956 91177308-0d34-0410-b5e6-96231b3b80d8
Use the simpler version of llvm::sys::fs::remove when possible.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198957 91177308-0d34-0410-b5e6-96231b3b80d8
[ms-abi] Adjusting Rules for Padding Between Bases

The presence of a VBPtr suppresses the presence of zero sized 
sub-objects in the non-virtual portion of the object in the context of 
determining if two base objects need alias-avoidance padding placed 
between them.

Test cases included.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198975 91177308-0d34-0410-b5e6-96231b3b80d8
Fix "regression" caused by updating our notion of POD to better match the C++11
rules: instead of requiring flexible array members to be POD, require them to
be trivially-destructible. This seems to be the only constraint that actually
matters here (and even then, it's questionable whether this matters).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198983 91177308-0d34-0410-b5e6-96231b3b80d8
[ms-abi] Change the way alignment is tracked

This patch more cleanly seperates the concepts of Preferred Alignment 
and Required Alignment.  Most notable that changes to Required Alignment 
do *not* impact preferred alignment until late in struct layout.  This 
is observable when using pragma pack and non-virtual bases and the use 
of tail padding when laying them out.

Test cases included.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198988 91177308-0d34-0410-b5e6-96231b3b80d8
PR12208: Under -fno-elide-constructors, don't forget to actually copy an NRVO
variable to the return slot. Patch by David Wiberg, with test case alterations
by me.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198991 91177308-0d34-0410-b5e6-96231b3b80d8
Use the appropriate SourceLocation for the template backtrace when doing
template argument deduction.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198995 91177308-0d34-0410-b5e6-96231b3b80d8
Add a new attribute 'enable_if' which can be used to control overload resolution based on the values of the function arguments at the call site.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198996 91177308-0d34-0410-b5e6-96231b3b80d8
Whoops! Fix major think-o in the first example in the documentation that I edited at 3am.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198997 91177308-0d34-0410-b5e6-96231b3b80d8