Changes

lldb-sanitized: Move MAX_PARALLEL_TESTS initialization to a place where
it can actually affect the cmake invocation.

[DWARF] Emit DW_AT_call_return_pc as an address
This reverts D53469, which changed llvm's DWARF emission to emit 
DW_AT_call_return_pc as a function-local offset. Such an encoding is not 
compatible with post-link block re-ordering tools and isn't standards- 
compliant.
In addition to reverting back to the original DW_AT_call_return_pc 
encoding, teach lldb how to fix up DW_AT_call_return_pc when the address 
comes from an object file pointed-to by a debug map. While doing this I 
noticed that lldb's support for tail calls that cross a DSO/object file 
boundary wasn't covered, so I added tests for that. This latter case 
exercises the newly added return PC fixup.
The dsymutil changes in this patch were originally included in D49887: 
the associated test should be sufficient to test DW_AT_call_return_pc 
encoding purely on the llvm side.
Differential Revision: https://reviews.llvm.org/D72489

DebugInfo: Factor out logic to update locations in MD_loop metadata, NFC
Factor out the logic needed to update debug locations contained within 
MD_loop metadata.
This refactor is preparation for a future change that also needs to 
rewrite MD_loop metadata.
rdar://45507940

Work around PR43337: don't try to use the vec_sel overloads for vector
long long, since clang's <altivec.h> doesn't provide it yet!

PR17164: Change clang's default behavior from
-flax-vector-conversions=all to -flax-vector-conversions=integer.
Summary: See proposal on cfe-dev: 
http://lists.llvm.org/pipermail/cfe-dev/2019-April/062030.html
Reviewers: SjoerdMeijer, eli.friedman
Subscribers: kristof.beyls, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67678

[NFC][IndVarSimplify] remove duplicate code in
widenWithVariantLoadUseCodegen.
Summary: Duplicate code in widenWithVariantLoadUseCodegen is removed and
also use assert to check unknown extension type as it should be filtered
out by the pre condition check before calling this function.
Reviewers: az, sanjoy, sebpop, efriedma, javed.absar, sanjoy.google
Reviewed By: efriedma
Subscribers: hiraditya, llvm-commits, amehsan
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72652

[mlir] Add shaped container component type interface
Summary:
* Add shaped container type interface which allows infering the shape,
element
 type and attribute of shaped container type separately. Show usage by
way of
 tensor type inference trait which combines the shape & element type in
 infering a tensor type;
 - All components need not be specified;
 - Attribute is added to allow for layout attribute that was previously
   discussed;
* Expand the test driver to make it easier to test new creation
instances
 (adding new operands or ops with attributes or regions would trigger
build
 functions/type inference methods);
 - The verification part will be moved out of the test and to verify
method
   instead of ops implementing the type inference interface in a follow
up;
* Add MLIRContext as arg to possible to create type for ops without
arguments,
 region or location;
* Also move out the section in OpDefinitions doc to separate
ShapeInference doc
 where the shape function requirements can be captured;
 - Part of this would move to the shape dialect and/or shape dialect ops
be
   included as subsection of this doc;
* Update ODS's variable usage to match camelBack format for builder,
 state and arg variables;
 - I could have split this out, but I had to make some changes around
   these and the inconsistency bugged me :)
Differential Revision: https://reviews.llvm.org/D72432

[NFC] Refactor InlineResult for readability
Summary: InlineResult is used both in APIs assessing whether a call site
is inlinable (e.g. llvm::isInlineViable) as well as in the function 
inlining utility (llvm::InlineFunction). It means slightly different 
things (can/should inlining happen, vs did it happen), and the implicit
casting may introduce ambiguity (casting from 'false' in InlineFunction
will default a message about hight costs, which is incorrect here).
The change renames the type to a more generic name, and disables 
implicit constructors.
Reviewers: eraman, davidxl
Reviewed By: davidxl
Subscribers: kerbowa, arsenm, jvesely, nhaehnle, eraman, hiraditya,
haicheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72744

[MachineScheduler][NFC] Don't swap when we can't cluster
https://reviews.llvm.org/D72706 tried to reduce reordering due to mem op 
clustering. This patch avoid doing the swap when we can't cluster.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D72800

lldb: Run TestCrossDSOTailCalls.py and TestCrossObjectTailCalls.py on
Darwin only
See https://bugs.llvm.org/show_bug.cgi?id=44561, these tests are failing 
on an aarch64/Linux bot:
http://lab.llvm.org:8011/builders/lldb-aarch64-ubuntu/builds/655
For some reason the backtrace the tests are expecting to find is 
incomplete.

[libc++] Make SFINAE'd member functions in string mutually exclusive.
This patch is needed in order to work around a GCC bug that fails to 
explicitly instantiate a non-template function of a class template when 
there is another overload that's a function template.
(See https://godbolt.org/z/4bUQ_b)
This patch SFINAE's away the function templates when the argument is a
basic_string.

[libc++] Explicitly mark basic_string<...>::npos with default
visibility.
This ensures that the version compiled into the library isn't 
accidentally hidden.

[libc++] Explicitly enumerate std::string external instantiations -
Attempt 2
  The GCC build failures have been addressed, and the LLDB failures were
 fixed by LLDB.
   I have also verified that the apple-clang 9.0 segfault no longer
  occurs.
Original Message:
 The external instantiation of std::string is a problem for libc++.
   Additions and removals of inline functions in string can cause ABI
   breakages, including introducing new symbols.
    This patch aims to:
     (1) Make clear which functions are explicitly instatiated.
     (2) Prevent new functions from being accidentally instantiated.
     (3) Allow a migration path for adding or removing functions from
the
     explicit instantiation over time.
    Although this new formulation is uglier, it is preferable from a
   maintainability and readability standpoint because it explicitly
   enumerates the functions we've chosen to expose in our ABI. Changing
   this list is non-trivial and requires thought and planning.
    (3) is achieved by making it possible to control the extern template
declaration
   separately from it's definition. Meaning we could add a new
definition to
   the dylib, wait for it to roll out, then add the extern template
   declaration to the header. Similarly, we could remove existing extern
   template declarations while still keeping the definition to prevent
ABI
   breakages.

[BasicBlock] add helper getPostdominatingDeoptimizeCall
It appears to be rather useful when analyzing Loops with multiple 
deoptimizing exits, perhaps merged ones. For now it is used in
LoopPredication, will be adding more uses in other loop passes.
Reviewers: asbirlea, fhahn, skatkov, spatel, reames Reviewed By: reames
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72754

DWARF: Simplify the way the return PC is attached to call site tags, NFC
This cleanup was suggested by Djordje in D72489.

[test] Move call-site-entry-linking.test into test/tools/dsymutil/X86
This should fix a failure on the clang-cmake-armv7-quick bot.

[libc++] Optimize basic_string::operator=(const basic_string&) for SSO
assignments
This change optimizes the operator=() assignment for short strings by
direcly copying the raw data from the source into the current instance.
This creates an optimized / inlined mempcy up to over 2X faster for
short string assignments. With inlining enabled for operator=,
performance is up to 6X faster.
Benchmarks 'as is': name                                    old time/op 
 new time/op    delta BM_StringAssignStr_Empty_Opaque         6.05ns ±
2%   3.59ns ± 0%  -40.67% BM_StringAssignStr_Empty_Transparent    5.15ns
± 0%   3.08ns ± 0%  -40.12% BM_StringAssignStr_Small_Opaque        
7.71ns ± 0%   3.59ns ± 0%  -53.45% BM_StringAssignStr_Small_Transparent 
  7.66ns ± 0%   3.09ns ± 0%  -59.66% BM_StringAssignStr_Large_Opaque    
    24.1ns ± 0%   24.9ns ± 0%   +3.22% 
BM_StringAssignStr_Large_Transparent    22.2ns ± 0%   22.8ns ± 0%  
+2.77% BM_StringAssignStr_Huge_Opaque           315ns ± 6%    320ns ± 5%
    ~ BM_StringAssignStr_Huge_Transparent      318ns ± 5%    321ns ± 4% 
   ~
Benchmarks with partial inlining operator=(): name                      
             old time/op   new time/op    delta 
BM_StringAssignStr_Empty_Opaque         5.94ns ± 2%   1.95ns ± 0% 
-67.21% BM_StringAssignStr_Empty_Transparent    5.14ns ± 0%   1.04ns ±
1%  -79.73% BM_StringAssignStr_Small_Opaque         7.69ns ± 0%   1.96ns
± 0%  -74.48% BM_StringAssignStr_Small_Transparent    7.65ns ± 0%  
1.04ns ± 0%  -86.40% BM_StringAssignStr_Large_Opaque         24.1ns ± 0%
  24.5ns ± 0%   +1.61% BM_StringAssignStr_Large_Transparent    22.2ns ±
0%   21.1ns ± 0%   -4.70% BM_StringAssignStr_Huge_Opaque           317ns
± 5%    323ns ± 4%     ~ BM_StringAssignStr_Huge_Transparent      318ns
± 5%    320ns ± 5%     ~
Patch by Martijn Vels (mvels@google.com) Reviewed as
https://reviews.llvm.org/D72704

[libc++] Fix parsing <string> in C++03.
Specifically, add a space between >> when closing templates.

Revert "[OPENMP]Do not use RTTI by default for NVPTX devices."
This reverts commit 23058f9dd4d7e18239fd63b6da52549514b45fda. It breaks 
builds of cuda code somehow in some cases.

[lldb/Debugger] Rename IO handler methods to be more meaningful (NFC)
Make it clear form the method names whether they are synchronous or 
asynchronous.

lldb-sanitized: Move MAX_PARALLEL_TESTS initialization to a place where
it can actually affect the cmake invocation.