ReleaseNotes: add lld/ELF notes

For the release/14.x branch.

Differential Revision: https://reviews.llvm.org/D119318

Author: MaskRay

lld/docs/ReleaseNotes.rst

@@ -30,30 +30,78 @@ ELF Improvements
   (`D107317 <https://reviews.llvm.org/D107317>`_)
 * ``--why-extract`` has been added to query why archive members/lazy object files are extracted.
   (`D109572 <https://reviews.llvm.org/D109572>`_)
-* ``e_entry`` no longer falls back to the address of ``.text`` if the entry symbol does not exist.
-  Instead, a value of 0 will be written.
-  (`D110014 <https://reviews.llvm.org/D110014>`_)
 * If ``-Map`` is specified, ``--cref`` will be printed to the specified file.
   (`D114663 <https://reviews.llvm.org/D114663>`_)
+* ``-z bti-report`` and ``-z cet-report`` are now supported.
+  (`D113901 <https://reviews.llvm.org/D113901>`_)
+* ``--lto-pgo-warn-mismatch`` has been added.
+  (`D104431 <https://reviews.llvm.org/D104431>`_)
+* Archives without an index (symbol table) are now supported and work with
+  ``--warn-backrefs``. One may build such an archive with ``llvm-ar rcS
+  [--thin]`` to save space.
+  (`D117284 <https://reviews.llvm.org/D117284>`_)
+  The archive index may be `entirely ignored <https://reviews.llvm.org/D119074>`
+  in a future release.
 * No longer deduplicate local symbol names at the default optimization level of ``-O1``.
   This results in a larger ``.strtab`` (usually less than 1%) but a faster link
-  time. Use optimization level ``-O2`` to restore the deduplication.
+  time. Use optimization level ``-O2`` to restore the deduplication. The ``-O2``
+  deduplication may be dropped in the future to help parallel ``.symtab`` write.
+* In relocatable output, relocations to discarded symbols now use tombstone
+  values.
+  (`D116946 <https://reviews.llvm.org/D116946>`_)
+* Orphan section placement now picks a more suitable segment. Previously the
+  algorithm might pick a readonly segment for a writable orphan section and make
+  the segment writable.
+  (`D111717 <https://reviews.llvm.org/D111717>`_)
+* An empty output section moved by an ``INSERT`` comment now gets appropriate
+  flags.
+  (`D118529 <https://reviews.llvm.org/D118529>`_)
+* Negation in a memory region attribute is now correctly handled.
+  (`D113771 <https://reviews.llvm.org/D113771>`_)
+* ``--compress-debug-sections=zlib`` is now run in parallel. ``{clang,gcc} -gz`` link
+  actions are significantly faster.
+  (`D117853 <https://reviews.llvm.org/D117853>`_)
+* "relocation out of range" diagnostics and a few uncommon diagnostics
+  now report an object file location beside a source file location.
+  (`D112518 <https://reviews.llvm.org/D117853>`_)
+* The write of ``.rela.dyn`` and ``SHF_MERGE|SHF_STRINGS`` sections (e.g.
+  ``.debug_str``) is now run in parallel.
 
 Architecture specific changes:
 
+* The AArch64 port now supports adrp+ldr and adrp+add optimizations.
+  ``--no-relax`` can suppress the optimization.
+  (`D112063 <https://reviews.llvm.org/D112063>`_)
+  (`D117614 <https://reviews.llvm.org/D117614>`_)
 * The x86-32 port now supports TLSDESC (``-mtls-dialect=gnu2``).
   (`D112582 <https://reviews.llvm.org/D112582>`_)
 * The x86-64 port now handles non-RAX/non-adjacent ``R_X86_64_GOTPC32_TLSDESC``
   and ``R_X86_64_TLSDESC_CALL`` (``-mtls-dialect=gnu2``).
   (`D114416 <https://reviews.llvm.org/D114416>`_)
+* The x86-32 and x86-64 ports now support mixed TLSDESC and TLS GD, i.e. mixing
+  objects compiled with and without ``-mtls-dialect=gnu2`` referencing the same
+  TLS variable is now supported.
+  (`D114416 <https://reviews.llvm.org/D114416>`_)
 * For x86-64, ``--no-relax`` now suppresses ``R_X86_64_GOTPCRELX`` and
   ``R_X86_64_REX_GOTPCRELX`` GOT optimization
   (`D113615 <https://reviews.llvm.org/D113615>`_)
+* ``R_X86_64_PLTOFF64`` is now supported.
+  (`D112386 <https://reviews.llvm.org/D112386>`_)
+* ``R_AARCH64_NONE``, ``R_PPC_NONE``, and ``R_PPC64_NONE`` in input REL
+  relocation sections are now supported.
 
 Breaking changes
 ----------------
 
-* ...
+* ``e_entry`` no longer falls back to the address of ``.text`` if the entry symbol does not exist.
+  Instead, a value of 0 will be written.
+  (`D110014 <https://reviews.llvm.org/D110014>`_)
+* ``--lto-pseudo-probe-for-profiling`` has been removed. In LTO, the compiler
+  enables this feature automatically.
+  (`D110209 <https://reviews.llvm.org/D110209>`_)
+* Use of ``--[no-]define-common``, ``-d``, ``-dc``, and ``-dp`` will now get a
+  warning. They will be removed or ignored in 15.0.0.
+  (`llvm-project#53660 <https://github.com/llvm/llvm-project/issues/53660>`_)
 
 COFF Improvements
 -----------------