ReleaseNotes: add lld/ELF notes

[MaskRay]

Summary

For release/12.x

[jhenderson]

There are a number of common grammar tweaks, I think would make sense. Based on a brief look at other release notes, I think I would phrase things as "XXX is/are now supported/retrained/..." rather than simply "is supported", as it emphasises what has changed. Similarly "XXX now has support for ..." and "XXX can now have/use/...". For "is fixed/added/improved" I'd say "has been fixed/...".

lld/docs/ReleaseNotes.rst

48

Links to one or more reviews? What has been improved about the support?

62

Links to one or more reviews? As it is, this release note is rather useless, I think.

65

This suggests this item could be a breaking change? Should it be in that section instead?

70

[MaskRay]

comments.
add more items

lld/docs/ReleaseNotes.rst

48

The commits collectively improved the support. I made a bunch of commits, sometimes with one commit regressed some untested cases.

[jhenderson]

Thanks for the update. A few more grammar suggestions for you inline.

lld/docs/ReleaseNotes.rst

27

Same for --lto-pseudo-probe-for-profiling and --no-lto-whole-program-visibility.

27–29

Not specific to this change, but you might as well fix it whilst here.

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Is there a review for this one?

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Should this be "many more"? Presumably there were some that were already supported?

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Is there an option (other than the CMake variable) to turn this off at runtime? If not "defaults" should probably be "uses".

[MaskRay]

comments

[jhenderson]

LGTM, thanks!

[MaskRay]

Closed by https://github.com/llvm/llvm-project/commit/e0e6b1e39e7e402cd74a8bf98a2728efbe38310e

lld/docs/ReleaseNotes.rst

 from the `LLVM releases web site <https://llvm.org/releases/>`_.
 
 Non-comprehensive list of changes in this release
 =================================================
 
 ELF Improvements
 ----------------
 
-* ``--error-handling-script`` is added to allow for user-defined handlers upon
+* ``--dependency-file`` has been added. (Similar to ``cc -M -MF``.)
+  (`D82437 <https://reviews.llvm.org/D82437>`_)
+* ``--error-handling-script`` has been added to allow for user-defined handlers upon
   missing libraries. (`D87758 <https://reviews.llvm.org/D87758>`_)
+* ``--exclude-libs`` can now localize defined version symbols and bitcode referenced libcall symbols.
+  (`D94280 <https://reviews.llvm.org/D94280>`_)
+* ``--gdb-index`` now works with DWARF v5 and ``--icf={safe,all}``.
+  (`D85579 <https://reviews.llvm.org/D85579>`_)
+  (`D89751 <https://reviews.llvm.org/D89751>`_)
+* ``--gdb-index --emit-relocs`` can now be used together.
+  (`D94354 <https://reviews.llvm.org/D94354>`_)
+* ``--icf={safe,all}`` conservatively no longer fold text sections with LSDA.
+  Previously ICF on ``-fexceptions`` code could be unsafe.
+  (`D84610 <https://reviews.llvm.org/D84610>`_)
+* ``--icf={safe,all}`` can now fold two sections with relocations referencing aliased symbols.
+  (`D88830 <https://reviews.llvm.org/D88830>`_)
+* ``--lto-pseudo-probe-for-profiling`` has been added.
+  (`D95056 <https://reviews.llvm.org/D95056>`_)
+* ``--no-lto-whole-program-visibility`` has been added.
+  (`D92060 <https://reviews.llvm.org/D92060>`_)
+* ``--oformat-binary`` has been fixed to respect LMA.
+  (`D85086 <https://reviews.llvm.org/D85086>`_)
+* ``--reproduce`` includes ``--lto-sample-profile``, ``--just-symbols``, ``--call-graph-ordering-file``, ``--retain-symbols-file`` files.
+* ``-r --gc-sections`` is now supported.
+  (`D84131 <https://reviews.llvm.org/D84131>`_)
+* A ``-u`` specified symbol will no longer change the binding to ``STB_WEAK``.
+  (`D88945 <https://reviews.llvm.org/D88945>`_)
+* ``--wrap`` support has been improved.
+  + If ``foo`` is not referenced, there is no longer an undefined symbol ``__wrap_foo``.
+  + If ``__real_foo`` is not referenced, there is no longer an undefined symbol ``foo``.
+* ``SHF_LINK_ORDER`` sections can now have zero ``sh_link`` values.
+* ``SHF_LINK_ORDER`` and non-``SHF_LINK_ORDER`` sections can now be mixed within an input section description.
+  (`D84001 <https://reviews.llvm.org/D84001>`_)
+* ``LOG2CEIL`` is now supported in linker scripts.
+  (`D84054 <https://reviews.llvm.org/D84054>`_)
+* ``DEFINED`` has been fixed to check whether the symbol is defined.
+  (`D83758 <https://reviews.llvm.org/D83758>`_)
+* An input section description may now have multiple ``SORT_*``.
+  The matched sections are ordered by radix sort with the keys being ``(SORT*, --sort-section, input order)``.
+  (`D91127 <https://reviews.llvm.org/D91127>`_)
+* Users can now provide a GNU style linker script to convert ``.ctors`` into ``.init_array``.
+  (`D91187 <https://reviews.llvm.org/D91187>`_)
+* An empty output section can now be discarded even if it is assigned to a program header.
+  (`D92301 <https://reviews.llvm.org/D92301>`_)
+* Non-``SHF_ALLOC`` sections now have larger file offsets than ``SHF_ALLOC`` sections.
+  (`D85867 <https://reviews.llvm.org/D85867>`_)
+* Some symbol versioning improvements.
+  + Defined ``foo@@v1`` now resolve undefined ``foo@v1`` (`D92259 <https://reviews.llvm.org/D92259>`_)
+  + Undefined ``foo@v1`` now gets an error (`D92260 <https://reviews.llvm.org/D92260>`_)
+* The AArch64 port now has support for ``STO_AARCH64_VARIANT_PCS`` and ``DT_AARCH64_VARIANT_PCS``.
+  (`D93045 <https://reviews.llvm.org/D93045>`_)
+* The AArch64 port now has support for ``R_AARCH64_LD64_GOTPAGE_LO15``.
+* The PowerPC64 port now detects missing R_PPC64_TLSGD/R_PPC64_TLSLD and disables TLS relaxation.
+  This allows linking with object files produced by very old IBM XL compilers.
+  (`D92959 <https://reviews.llvm.org/D92959>`_)
+* Many PowerPC PC-relative relocations are now supported.
+* ``R_PPC_ADDR24`` and ``R_PPC64_ADDR16_HIGH`` are now supported.
+* powerpcle is now supported. Tested with FreeBSD loader and freestanding.
+  (`D93917 <https://reviews.llvm.org/D93917>`_)
+* RISC-V: the first ``SHT_RISCV_ATTRIBUTES`` section is now retained.
+  (`D86309 <https://reviews.llvm.org/D86309>`_)
+* LTO pipeline now defaults to the new PM if the CMake variable ``ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER`` is on.
+  (`D92885 <https://reviews.llvm.org/D92885>`_)
 
 Breaking changes
 ----------------
 
-* ...
+* A COMMON symbol can now cause the fetch of an archive providing a ``STB_GLOBAL`` definition.
+  This behavior follows GNU ld newer than December 1999.
+  If you see ``duplicate symbol`` errors with the new behavior, check out `PR49226 <https://bugs.llvm.org//show_bug.cgi?id=49226>`_.
+  (`D86142 <https://reviews.llvm.org/D86142>`_)
 
 COFF Improvements
 -----------------
 
 * Error out clearly if creating a DLL with too many exported symbols.
   (`D86701 <https://reviews.llvm.org/D86701>`_)
 
 MinGW Improvements