Changes

[lit] Make internal diff work in pipelines
When using lit's internal shell, RUN lines like the following 
accidentally execute an external `diff` instead of lit's internal
`diff`:
```
# RUN: program | diff file -
# RUN: not diff file1 file2 | FileCheck %s
```
Such cases exist now, in `clang/test/Analysis` for example.  We are 
preparing patches to ensure lit's internal `diff` is called in such 
cases, which will then fail because lit's internal `diff` cannot 
currently be used in pipelines and doesn't recognize `-` as a 
command-line option.
To enable pipelines, this patch moves lit's `diff` implementation into 
an out-of-process script, similar to lit's `cat` implementation.  A 
follow-up patch will implement `-` to mean stdin.
Reviewed By: probinson, stella.stamenova
Differential Revision: https://reviews.llvm.org/D66574
llvm-svn: 375114

[lit] Extend internal diff to support `-` argument
When using lit's internal shell, RUN lines like the following 
accidentally execute an external `diff` instead of lit's internal
`diff`:
```
# RUN: program | diff file -
```
Such cases exist now, in `clang/test/Analysis` for example.  We are 
preparing patches to ensure lit's internal `diff` is called in such 
cases, which will then fail because lit's internal `diff` doesn't 
recognize `-` as a command-line option.  This patch adds support for
`-` to mean stdin.
Reviewed By: probinson, rnk
Differential Revision: https://reviews.llvm.org/D67643
llvm-svn: 375116

[clangd] Use our own relation kind.
Summary: Move the RelationKind from Serialization.h to Relation.h. This
patch doesn't introduce any breaking changes.
Reviewers: kadircet
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95,
cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D68981
llvm-svn: 375117

[OpenCL] Preserve addrspace in CGClass (PR43145)
PR43145 revealed two places where Clang was attempting to create a 
bitcast without considering the address space of class types during C++
class code generation.
Differential Revision: https://reviews.llvm.org/D68403
llvm-svn: 375118

[OPENMP]Fix thread id passed to outlined region in sequential parallel
regions.
The real global thread id must be passed to the outlined region instead 
of the zero thread id.
llvm-svn: 375119

Revert r375116: "[lit] Extend internal diff to support `-` argument"
This series of patches still breaks a Windows bot.
llvm-svn: 375120

Revert r375114: "[lit] Make internal diff work in pipelines"
This series of patches still breaks a Windows bot.
llvm-svn: 375121

[ARC] Basic support in gdb-remote process plugin
Differential Revision: https://reviews.llvm.org/D55718
llvm-svn: 375122

[ARC] Add SystemV ABI
Differential Revision: https://reviews.llvm.org/D55724
llvm-svn: 375123

[ObjC] Add some additional test cases around pointer conversions.
This is especially important for Objective-C++, which is entirely 
missing this testing at the moment.
This annotates with "FIXME" the cases which I change in the next patch
-- I primarily wanted to document the current state of things so that
the effect of the code change is made clear.
Differential Revision: https://reviews.llvm.org/D67982
llvm-svn: 375124

[ObjC] Diagnose implicit type coercion from ObjC 'Class' to object
pointer types.
For example, in Objective-C mode, the initialization of 'x' in:
```
 @implementation MyType
 + (void)someClassMethod {
   MyType *x = self;
 }
 @end
``` is correctly diagnosed with an incompatible-pointer-types warning,
but in Objective-C++ mode, it is not diagnosed at all -- even though 
incompatible pointer conversions generally become an error in C++.
This patch fixes that oversight, allowing implicit conversions involving
Class only to/from unqualified-id, and between qualified and unqualified
Class, where the protocols are compatible.
Note that this does change some behaviors in Objective-C, as well, as 
shown by the modified tests.
Of particular note is that assignment from from 'Class<MyProtocol>' to
'id<MyProtocol>' now warns. (Despite appearances, those are not 
compatible types. 'Class<MyProtocol>' is not expected to have instance 
methods defined by 'MyProtocol', while 'id<MyProtocol>' is.)
Differential Revision: https://reviews.llvm.org/D67983
llvm-svn: 375125

[lld][test] Fix use of escape character in an lld test on Windows
Summary: Glob support was improved to accept `\` as an escape character
in r375051, but reverted as r375052 due to a failure in this test on
Windows.
The reason this failure seems Windows specific is because the path
separator `\` is currently being relied on to be interpreted literally
instead of as an escape character. Per documentation on linker input
section wildcard patterns, this seems to be a bug in lld accepting `\`
as a literal instead of an escape character.
For example:
``` SECTIONS{ .foo :{ /path/to/foo.o(.foo) }} # OK: standard UNIX path 
SECTIONS{ .foo :{ C:/path/to/foo.o(.foo) }} # OK: windows accepts
slashes in either direction SECTIONS{ .foo :{ C:\\path\\to\\foo.o(.foo)
}} # OK: escape character used to match a literal \ SECTIONS{ .foo :{
C:\path\to\foo.o(.foo) }} # BAD: this actually matches the path
C:pathtofoo.o(.foo)
```
This avoids the problem in the test by using `%/T` in place of `%T` to
normalize the path separator to `/`, which windows should also accept.
This patch just fixes the test, and glob support will be be relanded
separately.
For a sample buildbot error, see:
http://lab.llvm.org:8011/builders/clang-x64-windows-msvc/builds/11578/steps/stage%201%20check/logs/stdio
Reviewers: evgeny777, ruiu, MaskRay, espindola
Reviewed By: ruiu, MaskRay
Subscribers: emaste, arichardson, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69074
llvm-svn: 375126

Fix an inverted condition in test.
llvm-svn: 375127

[lit] Create derived classes for serial/parallel test runs
The hope is that with a little OO we can nicely factor out the 
differences.
llvm-svn: 375128

[lit] Synthesize artificial deadline
We always want to use a deadline when calling `result.await`.  Let's 
synthesize an artificial deadline (positive infinity) to simplify code 
and do less busy waiting.
llvm-svn: 375129

[lit] Move computation of deadline up into base class
llvm-svn: 375130