[ORC] cloneToNewContext() can work with a const-ref to ThreadSafeModule

[llvm] Migrate llvm::make_unique to std::make_unique

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of

[llvm] Migrate llvm::make_unique to std::make_unique

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013

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[ORC] Change the locking scheme for ThreadSafeModule.

ThreadSafeModule/ThreadSafeContext are used to manage lifetimes and locking
for LLVMContexts in ORCv2. Prior to this patch contexts were locked

[ORC] Change the locking scheme for ThreadSafeModule.

ThreadSafeModule/ThreadSafeContext are used to manage lifetimes and locking
for LLVMContexts in ORCv2. Prior to this patch contexts were locked as soon
as an associated Module was emitted (to be compiled and linked), and were not
unlocked until the emit call returned. This could lead to deadlocks if
interdependent modules that shared contexts were compiled on different threads:
when, during emission of the first module, the dependence was discovered the
second module (which would provide the required symbol) could not be emitted as
the thread emitting the first module still held the lock.

This patch eliminates this possibility by moving to a finer-grained locking
scheme. Each client holds the module lock only while they are actively operating
on it. To make this finer grained locking simpler/safer to implement this patch
removes the explicit lock method, 'getContextLock', from ThreadSafeModule and
replaces it with a new method, 'withModuleDo', that implicitly locks the context,
calls a user-supplied function object to operate on the Module, then implicitly
unlocks the context before returning the result.

ThreadSafeModule TSM = getModule(...);
size_t NumFunctions = TSM.withModuleDo(
[](Module &M) { // <- context locked before entry to lambda.
return M.size();
});

Existing ORCv2 layers that operate on ThreadSafeModules are updated to use the
new method.

This method is used to introduce Module locking into each of the existing
layers.

llvm-svn: 367686

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Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

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[ORC] Add partitioning support to CompileOnDemandLayer2.

CompileOnDemandLayer2 now supports user-supplied partition functions (the
original CompileOnDemandLayer already supported these).

Partition

[ORC] Add partitioning support to CompileOnDemandLayer2.

CompileOnDemandLayer2 now supports user-supplied partition functions (the
original CompileOnDemandLayer already supported these).

Partition functions are called with the list of requested global values
(i.e. global values that currently have queries waiting on them) and have an
opportunity to select extra global values to materialize at the same time.

Also adds testing infrastructure for the new feature to lli.

llvm-svn: 343396

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[ORC] clang-format the ThreadSafeModule code.

Evidently I forgot to do this before committing r343055.

llvm-svn: 343288

[ORC] Add ThreadSafeModule and ThreadSafeContext wrappers to support concurrent
compilation of IR in the JIT.

ThreadSafeContext is a pair of an LLVMContext and a mutex that can be used to
lock that

[ORC] Add ThreadSafeModule and ThreadSafeContext wrappers to support concurrent
compilation of IR in the JIT.

ThreadSafeContext is a pair of an LLVMContext and a mutex that can be used to
lock that context when it needs to be accessed from multiple threads.

ThreadSafeModule is a pair of a unique_ptr<Module> and a
shared_ptr<ThreadSafeContext>. This allows the lifetime of a ThreadSafeContext
to be managed automatically in terms of the ThreadSafeModules that refer to it:
Once all modules using a ThreadSafeContext are destructed, and providing the
client has not held on to a copy of shared context pointer, the context will be
automatically destructed.

This scheme is necessary due to the following constraits: (1) We need multiple
contexts for multithreaded compilation (at least one per compile thread plus
one to store any IR not currently being compiled, though one context per module
is simpler). (2) We need to free contexts that are no longer being used so that
the JIT does not leak memory over time. (3) Module lifetimes are not
predictable (modules are compiled as needed depending on the flow of JIT'd
code) so there is no single point where contexts could be reclaimed.

JIT clients not using concurrency can safely use one ThreadSafeContext for all
ThreadSafeModules.

JIT clients who want to be able to compile concurrently should use a different
ThreadSafeContext for each module, or call setCloneToNewContextOnEmit on their
top-level IRLayer. The former reduces compile latency (since no clone step is
needed) at the cost of additional memory overhead for uncompiled modules (as
every uncompiled module will duplicate the LLVM types, constants and metadata
that have been shared).

llvm-svn: 343055

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