Changes

[ORC] Add support for emulated TLS to ORCv2.
This commit adds a ManglingOptions struct to IRMaterializationUnit, and
replaces IRCompileLayer::CompileFunction with a new
IRCompileLayer::IRCompiler class. The ManglingOptions struct defines the
emulated-TLS state (via a bool member, EmulatedTLS, which is true if
emulated-TLS is enabled and false otherwise). The 
IRCompileLayer::IRCompiler class wraps an IRCompiler (the same way that
the CompileFunction typedef used to), but adds a method to return the 
IRCompileLayer::ManglingOptions that the compiler will use.
These changes allow us to correctly determine the symbols that will be
produced when a thread local global variable defined at the IR level is
compiled with or without emulated TLS. This is required for ORCv2, where
MaterializationUnits must declare their interface up-front.
Most ORCv2 clients should not require any changes. Clients writing
custom IR compilers will need to wrap their compiler in an
IRCompileLayer::IRCompiler, rather than an
IRCompileLayer::CompileFunction, however this should be a 
straightforward change (see modifications to CompileUtils.* in this
patch for an example).

[clang][IFS][test] Temporary work around for in-process cc1 ASAN issues.
When using in-process cc1, the Clang Interface Stubs pipeline setup 
exposes an ASAN bug. I am still investigating this issue but want to 
green the bots for now. I don't think this is a huge issue since the 
Clang Interface Stubs Driver setup code is the only code path that sets 
up such a pipeline (ie N cc1's for N c files followed by another N cc1's 
for to generate stub files for the same N c files).
This issue is being discussed in https://reviews.llvm.org/D69825. If a
resolution is not found soon, a bugzilla filling will be in order.

[ORC] Fix a missing move in ce2207abaf9.
This should fix the build failure at 
http://lab.llvm.org:8011/builders/clang-cmake-x86_64-sde-avx512-linux/builds/32524 
and others.

Resubmit: [AMDGPU] Invert the handling of skip insertion.
The current implementation of skip insertion (SIInsertSkip) makes it a 
mandatory pass required for correctness. Initially, the idea was to have
an optional pass. This patch inserts the s_cbranch_execz upfront during
SILowerControlFlow to skip over the sections of code when no lanes are
active. Later, SIRemoveShortExecBranches removes the skips for short
branches, unless there is a sideeffect and the skip branch is really
necessary.
This new pass will replace the handling of skip insertion in the 
existing SIInsertSkip Pass.
Differential revision: https://reviews.llvm.org/D68092

[AMDGPU] SIRemoveShortExecBranches should not remove branches exiting
loops
Summary: Check that a s_cbranch_execz is not a loop exit before removing
it. As the pass is generating infinite loops.
Reviewers: cdevadas, arsenm, nhaehnle
Reviewed By: nhaehnle
Subscribers: kzhuravl, jvesely, wdng, yaxunl, tpr, t-tye, hiraditya,
kerbowa, llvm-commits, dstuttard, foad
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72997

[gn build] Port e53a9d96e6a

[ORC] Update examples to incorporate changes in ce2207abaf9.
This should fix the builders that were failing due to broken JIT
examples after ce2207abaf9.

[DA][TTI][AMDGPU] Add option to select GPUDA with TTI
Summary: Enable the new diveregence analysis by default for AMDGPU.
Reviewers: rampitec, nhaehnle, arsenm
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye,
hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73049

Update clang-interpreter example to incorporate changes in ce2207abaf9.

[LICM] Don't cache AliasSetTrackers when run under legacy PM
Summary: This is the first step towards complete removal of AST caching
from LICM. Attempts to keep LICM's AST cache up to date across passes
can lead to miscompiles like this one:
https://bugs.llvm.org/show_bug.cgi?id=44320.
LICM has already switched to using MemorySSA to do sinking and hoisting 
and only builds an AliasSetTracker on demand for the promoteToScalars 
step, without caching it from one LICM instance to the next. Given this, 
we don't have compile-time reasons to keep AST caching any more. The
only scenario where the caching would be used currently is when using
the LegacyPassManager and setting -enable-mssa-loop-dependency=false.
This switch should help us to surface any possible issues that may arise 
along this way, also it turns subsequent removal of AST caching into
NFC.
Reviewers: asbirlea, fhahn, efriedma, reames
Reviewed By: asbirlea
Subscribers: hiraditya, george.burgess.iv, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73081

[lldb/Initializers] Move all ObjC initializers into AppleObjCRuntime
AppleObjCRuntime is the main entry point to the plugin with the same 
name. This is part of a greater refactoring to auto generate the 
initializers. NFC.
Differential revision: https://reviews.llvm.org/D73121

[ORC] Fix the LLJITWithObjectCache example to address changes in
ce2207abaf9.

[AArch64][GlobalISel] Fix llvm.returnaddress(0) selection when LR is
clobbered.
The code was originally ported from SelectionDAG, which does CSE behind
the scenes automatically. When copying the return address from LR live
into the function, we need to make sure to use the single copy on
function entry. Any later copy from LR could be using clobbered junk.
Implement this by caching the copy in the per-MF state in the selector.
Should hopefully fix the AArch64 sanitiser buildbot failure.

[lldb] Add a display name to ClangASTContext instances
Summary: I often struggle to understand what exactly LLDB is doing by
looking at our expression evaluation logging as our messages look like
this:
``` CompleteTagDecl[2] on (ASTContext*)0x7ff31f01d240 Completing
(TagDecl*)0x7ff31f01d568 named DeclName1
```
From the log messages it's unclear what this ASTContext is. Is it the
scratch context, the expression context, some decl vendor context or a
context from a module? The pointer value isn't helpful for anyone unless
I'm in a debugger where I could inspect the memory at the address. But
even with a debugger it's not easy to figure out what this ASTContext is
without having deeper understanding about all the different ASTContext
instances in LLDB (e.g., valid SourceLocation from the file system
usually means that this is the Objective-C decl vendor, a file name from
multiple expressions is probably the scratch context, etc.).
This patch adds a name field to ClangASTContext instances that we can
use to store a name which can be used for logging and debugging. With
this our log messages now look like this:
``` CompleteTagDecl[2] on scratch ASTContext. Completing
(TagDecl*)0x7ff31f01d568 named Foo
``` We can now also just print a ClangASTContext from the debugger and
see a useful name in the `m_display_name` field, e.g.
```
 m_display_name = "AST for /Users/user/test/main.o";
```
Reviewers: shafik, labath, JDevlieghere, mib
Reviewed By: shafik
Subscribers: clayborg, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D72391

[VE] i<N> and fp32/64 arguments, return values and constants
Summary: Support for i<N> and fp32/64 arguments (in register), return
values and constants along with tests.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D73092

[Concepts] Fix incorrect recovery in TryAnnotateTypeConstraint
TryAnnotateTypeConstraint would not put the scope specifier back into
the token stream when faced with a non-concept name after a scope
specifier.

[clang][index] Index the injected class name types.
Summary: Currently, we (clangd) are missing this kind of references.
Reviewers: kadircet
Subscribers: ilya-biryukov, arphaman, usaxena95, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73109

[llvm-as] Fix assembling of index with multiple summaries sharing single
GUID
Differential revision: https://reviews.llvm.org/D73091

[clangd] Handle the missing injectedClassNameType in targetDecl.
Reviewers: sammccall
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet,
usaxena95, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73102

Change the googlemock link
Summary: This commit changes the googlemock link in the Testing Guide
doc as googlemock is absorbed into the GoogleTest project
Reviewers: shafik, labath, JDevlieghere, mib
Reviewed By: labath
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73082

[lldb] Fix an asan error from 27df2d9f556c
This error is caused by a combination of a couple of factors:
- the test accidentally creating a list with a single (empty) FileSpec
 instead of an empty list
- lldb overzeleously converting empty strings into nullptrs
- asan overzeleously validating symlink(2) arguments (the real symlink
 call would just fail with EFAULT)
I fix this by using FileSpec::GetPath instead of GetCString. This avoids 
the nullptr and also avoids inserting the path into the global string 
pool.
I also enhance the test case to test both empty paths and empty lists.

[mlir][orc] unbreak MLIR ExecutionEngine after ORC changes
Changes to ORC in ce2207abaf9a925b35f15ef92aaff6b301ba6d22 changed the 
APIs in IRCompileLayer, now requiring the custom compiler to be wrapped 
in IRCompileLayer::IRCompiler. Even though MLIR relies on Orc 
CompileUtils, the type is still visible in several places in the code. 
Adapt those to the new API.

[Concepts] Fix bug when referencing function parameters in instantiated
function template requires clause
Fixes bug #44613 - instantiated parameters were not being added when
instantiating the requires clauses.

[ARM][MVE] Clear MaskedInsts vector
In MVETailPredication, clear the vector before running on a new loop.
Differential Revision: https://reviews.llvm.org/D73048

[llvm-readobj] - Rewrite gnuhash.test test to stop using precompiled
objects.
This rewrites the test to use YAML and removes 4 precompiled object.
Differential revision: https://reviews.llvm.org/D73096

[Doc] Update requirements for masked load/store

[llvm-exegesis] Serial snippet: Restrict the set of back-to-back
instructions
Summary: Right now when picking a back-to-back instruction at random, we
might select instructions that we do not know how to handle. Add a
ExegesisTarget hook to possibly filter instructions.
Reviewers: gchatelet
Subscribers: tschuett, mstojanovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73161

[lldb] s/lldb/%lldb in two tests
%lldb is the proper substitution. Using "lldb" can cause us to execute 
the system lldb instead of the one we are testing. This happens at least 
in standalone builds.

[Alignment][NFC] Use Align with CreateMaskedStore
Summary: This is patch is part of a series to introduce an Alignment
type. See this thread for context:
http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html See this
patch for the introduction of the type: https://reviews.llvm.org/D64790
Reviewers: courbet
Subscribers: hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D73106

[Concepts] Placeholder constraints and abbreviated templates
This patch implements P1141R2 "Yet another approach for constrained
declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the
wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in
GetTypeSpecTypeForDeclarator, using the same logic
 previously used for generic lambdas, now unified with abbreviated
templates, by:
 - Tracking the template parameter lists in the Declarator object
 - Tracking the template parameter depth before parsing function
declarators (at which point we can match template
   parameters against scope specifiers to know if we have an explicit
template parameter list to append invented parameters
   to or not).
- When encountering an AutoType in a parameter context we check a stack
of InventedTemplateParameterInfo structures that
 contain the info required to create and accumulate invented template
parameters (fields that were already present in
 LambdaScopeInfo, which now inherits from this class and is looked up
when an auto is encountered in a lambda context).
Resubmit after incorrect check in NonTypeTemplateParmDecl broke lldb.
Differential Revision: https://reviews.llvm.org/D65042

Add support for (expressing) vscale.
In LLVM IR, vscale can be represented with an intrinsic. For some
targets, this is equivalent to the constexpr:
  getelementptr <vscale x 1 x i8>, <vscale x 1 x i8>* null, i32 1
This can be used to propagate the value in CodeGenPrepare.
In ISel we add a node that can be legalized to one or more instructions
to materialize the runtime vector length.
This patch also adds SVE CodeGen support for VSCALE, which maps this 
node to RDVL instructions (for scaled multiples of 16bytes) or CNT[HSD] 
instructions (scaled multiples of 2, 4, or 8 bytes, respectively).
Reviewers: rengolin, cameron.mcinally, hfinkel, sebpop, SjoerdMeijer,
efriedma, lattner
Reviewed by: efriedma
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68203

Revert "[Concepts] Fix bug when referencing function parameters in
instantiated function template requires clause"
This temporarily reverts commit 45538b5fb280e5b2903f7924fd4fa5b07a6dd3ea
which breaks a test.

[clangd] Do not duplicate TemplatedDecls in findExplicitReferences
Reviewers: hokein
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95,
cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73101

[LLD][ELF][ARM] Don't apply --fix-cortex-a8 to relocatable links.
The --fix-cortex-a8 is sensitive to alignment and the precise
destination of branch instructions. These are not knowable at
relocatable link time. We follow GNU ld and the --fix-cortex-a53-843419
(D72968) by not patching the code when there is a relocatable link.
Differential Revision: https://reviews.llvm.org/D73100

[AArch64][SVE] Add intrinsic for non-faulting loads
Summary: This patch adds the llvm.aarch64.sve.ldnf1 intrinsic, plus DAG
combine rules for non-faulting loads and sign/zero extends
Reviewers: sdesmalen, efriedma, andwar, dancgr, mgudim, rengolin
Reviewed By: sdesmalen
Subscribers: tschuett, kristof.beyls, hiraditya, rkruppe, psnobl,
cameron.mcinally, cfe-commits, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71698