Release notes for
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GNU Arm Embedded Toolchain 2020-q4-major
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This release includes bare metal pre-built binaries for AArch32 EABI targets,
which can be hosted on:
* Windows 10 or later on 32/64-bit architecture
* Linux
  - on AArch64 (RHEL 7, Ubuntu 14.04 or later)
  - on x86_64 (RHEL 7, Ubuntu 16.04 or later)
* Mac OS X 10.14 or later on 64-bit architecture

For Windows, the binaries are provided with an installer and as a zip file.
For Linux, the binaries are provided as tarball files.
For Mac OS X, the binaries are provided as tarball and pkg files.

The release also contains source code package (together with build scripts and
instructions to setup the build environment), which is composed of:

  * gcc : refs/vendors/ARM/heads/arm-10
    git://gcc.gnu.org/git/gcc.git commit 3b91aab15443ee150b2ba314a4b26645ce8d713b

  * binutils : binutils-2_35-branch
    git://sourceware.org/git/binutils-gdb.git commit d9a444bca66bf4b0d328acb547ca114081f3fd87

  * newlib and newlib-nano : newlib-3.3.0
    git://sourceware.org/git/newlib-cygwin.git commit 6d79e0a58866548f435527798fbd4a6849d05bc7

  * gdb : gdb-10-branch
    git://sourceware.org/git/binutils-gdb.git commit f3fb4a77f29a99ffa2e1460dfa652081cdbd38be

Note that some or all of the following prerequisites are downloaded when
building from source:

  * EnvVarUpdate NSIS script :
    http://nsis.sourceforge.net/mediawiki/images/a/ad/EnvVarUpdate.7z

  * expat 2.1.1 :
    https://downloads.sourceforge.net/project/expat/expat/2.1.1/expat-2.1.1.tar.bz2

  * gmp 6.1.0 :
    https://gmplib.org/download/gmp/gmp-6.1.0.tar.bz2

  * isl 0.18 :
    http://isl.gforge.inria.fr/isl-0.18.tar.xz

  * libelf 0.8.13 :
    https://fossies.org/linux/misc/old/libelf-0.8.13.tar.gz

  * libiconv 1.15 :
    https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.15.tar.gz

  * mpc 1.0.3 :
    ftp://ftp.gnu.org/gnu/mpc/mpc-1.0.3.tar.gz

  * mpfr 3.1.4 :
    http://www.mpfr.org/mpfr-3.1.4/mpfr-3.1.4.tar.bz2

  * python 2.7.7 :
    https://www.python.org/ftp/python/2.7.7/python-2.7.7.msi

  * zlib 1.2.8 :
    http://www.zlib.net/fossils/zlib-1.2.8.tar.gz

Features:
* All GCC 10.2 features

Tests:
* Targets:
  + Variety of Cortex-M0/M0+/M3/M4/M7/A9 boards
  + Qemu
  + Arm Fast Models

Notable changes in 2020-q4-major release:
* Added support for:
  + M-profile Vector Extension (MVE) assembler and intrinsics
  + Custom Datapath Extension (CDE)
  + Cortex-M55

* Fixed issue where load or store of __fp16 type together with MVE
  might generate invalid code.

* Fixed issue https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91816
  where the compiler was generating a conditional branch in Thumb2,
  which was too far for b{cond} to handle.

* Fixed internal errors in arm and aarch64 GAS when assembling code
  that attempts a negative .org.

* Fixed issue https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96191
  where the -fstack-protector option was leaving the canary value
  in a temporary register on return from the function.

Known issues:
* Doing IPA on CMSE generates a linker error:
The linker will error out when resulting object file contains a symbol for
the clone function with the __acle_se prefix that has a non-local binding.
  Issue occurs when compiling binaries for M-profile Secure Extensions where
the compiler may decide to clone a function with the cmse_nonsecure_entry
attribute.
  Although cloning nonsecure entry functions is legal, as long as the clone
is only used inside the secure application, the clone function itself should
not be seen as a secure entry point and so it should not have the __acle_se
prefix.
  A possible workaround for this is to add a 'noclone' attribute to
functions with the 'cmse_nonsecure_entry'. This will prevent GCC from cloning
such functions.