ReleaseNotes: tidy up

  the `developer documentation <DeveloperPolicy.html#c-api-changes>`_ for more

  information.

* The C API function LLVMLinkModules is deprecated. It will be removed in the

  3.9 release. Please migrate to LLVMLinkModules2. Unlike the old function the

* The C API function ``LLVMLinkModules`` is deprecated. It will be removed in the

  3.9 release. Please migrate to ``LLVMLinkModules2``. Unlike the old function the

  new one

   * Doesn't take an unused parameter.

   * Destroys the source instead of only damaging it.

   * Does not record a message. Use the diagnostic handler instead.

* The C API functions LLVMParseBitcode, LLVMParseBitcodeInContext,

  LLVMGetBitcodeModuleInContext and LLVMGetBitcodeModule have been deprecated.

* The C API functions ``LLVMParseBitcode``, ``LLVMParseBitcodeInContext``,

  ``LLVMGetBitcodeModuleInContext`` and ``LLVMGetBitcodeModule`` have been deprecated.

  They will be removed in 3.9. Please migrate to the versions with a 2 suffix.

  Unlike the old ones the new ones do not record a diagnostic message. Use

  the diagnostic handler instead.

* The deprecated C APIs LLVMGetBitcodeModuleProviderInContext and

  LLVMGetBitcodeModuleProvider have been removed.

* The deprecated C APIs ``LLVMGetBitcodeModuleProviderInContext`` and

  ``LLVMGetBitcodeModuleProvider`` have been removed.

* The deprecated C APIs LLVMCreateExecutionEngine, LLVMCreateInterpreter,

  LLVMCreateJITCompiler, LLVMAddModuleProvider and LLVMRemoveModuleProvider

* The deprecated C APIs ``LLVMCreateExecutionEngine``, ``LLVMCreateInterpreter``,

  ``LLVMCreateJITCompiler``, ``LLVMAddModuleProvider`` and ``LLVMRemoveModuleProvider``

  have been removed.

* With this release, the C API headers have been reorganized to improve build

  Core.h so nothing should change for projects directly including the headers,

  but transitive dependencies may be affected.

* llvm-ar now suports thin archives.

* llvm-ar now supports thin archives.

* llvm doesn't produce .data.rel.ro.local or .data.rel sections anymore.

* llvm doesn't produce ``.data.rel.ro.local`` or ``.data.rel`` sections anymore.

* aliases to available_externally globals are now rejected by the verifier.

* Aliases to ``available_externally`` globals are now rejected by the verifier.

* the IR Linker has been split into IRMover that moves bits from one module to

* The IR Linker has been split into ``IRMover`` that moves bits from one module to

  another and Linker proper that decides what to link.

* Support for dematerializing has been dropped.

* RegisterScheduler::setDefault was removed. Targets that used to call into the

  command line parser to set the DAGScheduler, and that don't have enough

  control with setSchedulingPreference, should look into overriding the

  SubTargetHook "getDAGScheduler()".

* ``RegisterScheduler::setDefault`` was removed. Targets that used to call into the

  command line parser to set the ``DAGScheduler``, and that don't have enough

  control with ``setSchedulingPreference``, should look into overriding the

  ``SubTargetHook`` "``getDAGScheduler()``".

* ``ilist_iterator<T>`` no longer has implicit conversions to and from ``T*``,

  since ``ilist_iterator<T>`` may be pointing at the sentinel (which is usually

* ``ilist_node<T>::getNextNode()`` and ``ilist_node<T>::getPrevNode()`` now

  fail at compile time when the node cannot access its parent list.

  Previously, when the sentinel was was an ``ilist_half_node<T>``, this API

  could return the sentinal instead of ``nullptr``.  Frustrated callers should

  could return the sentinel instead of ``nullptr``.  Frustrated callers should

  be updated to use ``iplist<T>::getNextNode(T*)`` instead.  Alternatively, if

  the node ``N`` is guaranteed not to be the last in the list, it is safe to

  call ``&*++N->getIterator()`` directly.

  variables are converted to calls to ``__emutls_get_address`` in the runtime

  library.

* MSVC compatible exception handling has been completely overhauled. New

* MSVC-compatible exception handling has been completely overhauled. New

  instructions have been introduced to facilitate this:

  `New exception handling instructions <ExceptionHandling.html#new-exception-handling-instructions>`_. 

  While we have done our best to test this feature thoroughly, it would

  not be completely surprising if there were a few lingering issues that

  early adopters might bump into.

.. NOTE

   For small 1-3 sentence descriptions, just add an entry at the end of

   this list. If your description won't fit comfortably in one bullet

   point (e.g. maybe you would like to give an example of the

   functionality, or simply have a lot to talk about), see the `NOTE` below

   for adding a new subsection.

* ... next change ...

.. NOTE

   If you would like to document a larger change, then you can add a

   subsection about it right here. You can copy the following boilerplate

   and un-indent it (the indentation causes it to be inside this comment).

   Special New Feature

   -------------------

   Makes programs 10x faster by doing Special New Thing.

Changes to the ARM Backends

---------------------------

* Gained some additional code size improvements, though there's still a long road

  ahead, especially for older cores.

* Added some EABI floating point comparison functions to Compiler-RT

* Added support for Windows+GNU triple, +features in -mcpu/-march options.

* Added support for Windows+GNU triple, ``+features`` in ``-mcpu``/``-march`` options.

Changes to the MIPS Target

* Address spaces 1 to 255 are now reserved for software use and conversions

  between them are no-op casts.

* Removed the ``mips16`` value for the -mcpu option since it is an :abbr:`ASE

* Removed the ``mips16`` value for the ``-mcpu`` option since it is an :abbr:`ASE

  (Application Specific Extension)` and not a processor. If you were using this,

  please specify another CPU and use ``-mips16`` to enable MIPS16.

* Removed ``copy_u.w`` from 32-bit MSA and ``copy_u.d`` from 64-bit MSA since

* Added support for atomic load and atomic store.

* Corrected debug info when dynamically re-aligning the stack.

Integrated Assembler

^^^^^^^^^^^^^^^^^^^^

We have made a large number of improvements to the integrated assembler for

MIPS. In this release, the integrated assembler isn't quite production-ready

since there are a few known issues related to bare-metal support, checking

* Thread Sanitizer (TSAN) is now supported for PowerPC

* New MI peephole pass to clean up redundand XXPERMDI instructions  

* New MI peephole pass to clean up redundant XXPERMDI instructions  

* Add branch hints to highly biased branch instructions (code reaching

  unreachable terminators and exceptional control flow consructs)

  unreachable terminators and exceptional control flow constructs)

* Promote boolean return values to integer to prevent excessive usage of

  condition registers

Changes to the X86 Target

-----------------------------

 During this release ...

* TLS is enabled for Cygwin as emutls.

* Smaller code for materializing 32-bit 1 and -1 constants at ``-Os``.

Changes to the OCaml bindings

-----------------------------

 During this release ...

* The ocaml function link_modules has been replaced with link_modules' which

  uses LLVMLinkModules2.

If you have any questions or comments about LLVM, please feel free to contact

us via the `mailing lists <http://llvm.org/docs/#maillist>`_.