Changes/BINUTILS236

Changes/Binutils 2.36

Summary

Rebase the binutils package from version 2.35.1 to version 2.36.

Owner

• Name: Nick Clifton [1]
• Email: nickc@redhat.com

Current status

• Targeted release: Fedora 34
• Last updated: 2020-12-09
• FESCo issue: <will be assigned by the Wrangler>
• Tracker bug: <will be assigned by the Wrangler>
• Release notes tracker: <will be assigned by the Wrangler>

Detailed Description

Switch the binutils package from being based on the 2.35.1 release of the GNU binutils to being based on the 2.36 release. This release will bring in numerous bug fixes, as well as support for new x86 and ARM architecture extensions.

Benefit to Fedora

The main benefit will be the bug fixes and the improvements to the linker and assembler. Whilst invisible to ordinary users these changes will benefit package maintainers and application developers.

Scope

• Proposal owners:

Change the source parameter in the binutils.spec rpm and adjust the local patches to take account of the bugs that are now already fixed. This is a significant change to the underlying tools used to build Fedora and so there should be a mass rebuild in order for the changes to be noticed across the system.

• Other developers: None

• Release engineering: https://pagure.io/releng/issue/9898

A mass rebuilt will be required.

• Policies and guidelines: No documents need to be updated.

• Trademark approval: N/A (not needed for this Change)

• Alignment with Objectives:

The rebase of the binutils will bring with it improved support for smaller architectures (eg ARM, RISC-V, MIPS) which in turn will align with the Fedora Internet of Things objective.

Upgrade/compatibility impact

The binutils are backwards compatible with previous releases, so no changes should be necessary.

How To Test

The binutils package does include its own set of testsuites which check basic functionality. The real test however is by rebuilding other packages which depend upon the binutils, or more likely, upon gcc. If these packages continue to work then the binutils update has not broken anything.

User Experience

The change should not be noticeable to the user.

Dependencies

This update has no hard dependencies on any other package. There are other packages that do depend upon the binutils however. Most notably gcc and redhat-rpm-config.

Contingency Plan

• Contingency mechanism:

Revert to the 2.35.1 binutils as currently used in rawhide. This work can be done by me, should it prove necessary.

• Contingency deadline: Beta freeze.

• Blocks release? No
• Blocks product? None

Documentation

This rebase brings with it many bug fixes, plus the following notable new features:

  New features in the Assembler:
   
   General:
    * When setting the link order attribute of ELF sections, it is now
      possible to use a numeric section index instead of symbol name.
    * Added a .nop directive to generate a single no-op instruction in
      a target neutral manner.  This instruction does have an effect on
      DWARF line number generation, if that is active.
    * Removed --reduce-memory-overheads and --hash-size as gas now
      uses hash tables that can be expand and shrink automatically.

    X86/x86_64:
      * Add support for AVX VNNI, HRESET, UINTR, TDX, AMX and Key
        Locker instructions. 
      * Support non-absolute segment values for lcall and ljmp.
      * Add {disp16} pseudo prefix to x86 assembler.
      * Configure with --enable-x86-used-note by default for Linux/x86.
      
    ARM/AArch64:
      * Add support for Cortex-A78, Cortex-A78AE and Cortex-X1,
        Cortex-R82, Neoverse V1, and Neoverse N2 cores.
      * Add support for ETMv4 (Embedded Trace Macrocell), ETE (Embedded
        Trace Extension), TRBE (Trace Buffer Extension), CSRE (Call
        Stack Recorder Extension) and BRBE (Branch Record Buffer
        Extension) system registers.
      * Add support for Armv8-R and Armv8.7-A ISA extensions.
      * Add support for DSB memory nXS barrier, WFET and WFIT
        instruction for Armv8.7.
      * Add support for +csre feature for -march. Add CSR PDEC
        instruction for CSRE feature in AArch64.
      * Add support for +flagm feature for -march in Armv8.4 AArch64.
      * Add support for +ls64 feature for -march in Armv8.7
        AArch64. Add atomic 64-byte load/store instructions for this
        feature. 
      * Add support for +pauth (Pointer Authentication) feature for
        -march in AArch64.

   New features in the Linker:
   
     * Add --error-handling-script=<NAME> command line option to allow
       a helper script to be invoked when an undefined symbol or a
       missing library is encountered.  This option can be suppressed
       via the configure time switch: --enable-error-handling-script=no.
     * Add -z x86-64-{baseline|v[234]} to the x86 ELF linker to mark
       x86-64-{baseline|v[234]} ISA level as needed.
     * Add -z unique-symbol to avoid duplicated local symbol names.
     * The creation of PE format DLLs now defaults to using a more
       secure set of DLL characteristics.
     * The linker now deduplicates the types in .ctf sections.  The new 
        command-line option --ctf-share-types describes how to do this:
        its default value, share-unconflicted, produces the most compact
        output.
     * The linker now omits the "variable section" from .ctf sections
       by default, saving space.  This is almost certainly what you
       want unless you are working on a project that has its own
       analogue of symbol tables that are not reflected in the ELF
       symtabs.

 New features in other binary tools:

     * The ar tool's previously unused l modifier is now used for
       specifying dependencies of a static library. The arguments of
       this option (or --record-libdeps long form option) will be
       stored verbatim in the __.LIBDEP member of the archive, which
       the linker may read at link time.
     * Readelf can now display the contents of LTO symbol table
       sections when asked to do so via the --lto-syms command line
       option.
     * Readelf now accepts the -C command line option to enable the
       demangling of symbol names.  In addition the --demangle=<style>,
       --no-demangle, --recurse-limit and --no-recurse-limit options
       are also now available.