[Bug ld/28910] New: GNU-ld: ARM: Issues when trying to set target output architecture

[krjdev at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28910

            Bug ID: 28910
           Summary: GNU-ld: ARM: Issues when trying to set target output
                    architecture
           Product: binutils
           Version: 2.36.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ld
          Assignee: unassigned at sourceware dot org
          Reporter: krjdev at gmail dot com
  Target Milestone: ---

I noticed two issues in the ARM port from GNU-ld. It's a special case when the
output target is set manually (linker script or command line). When no target
output architecture is set, linking of the objects works fine with GNU-ld.

Testcase:

I used a current project from me which targets a Cortex-M7 (Armv7E-M).
GNU-ld is invoked directly within a Makefile, not via GCC.

Compiled the source code with the following GCC options:
CCFLAGS         += -march=armv7e-m
CCFLAGS         += -mcpu=cortex-m7

Issue #1 - command line with long option "--architecture ARCH"

Setting the target output architecture doesn't work with the command line
option when using the long format. GNU-ld doesn't recognize the option and
aborts with an error. I don't know if this is a real issue or an usage mistake
from me when I use the long option instead of the short form.

Tried it with...
$ arm-none-eabi-ld --architecture armv7e-m
arm-none-eabi-ld: Error: unable to disambiguate: --architecture (did you mean
---architecture ?)

...and...
arm-none-eabi-ld --architecture=armv7e-m
arm-none-eabi-ld: Error: unable to disambiguate: --architecture=armv7e-m (did
you mean ---architecture=armv7e-m ?)

Works with the short form:
$ arm-none-eabi-ld -A armv7e-m

Issue #2 - linker script

If I don't use the working short form for setting the target output
architecture
and use a linker script instead with...

OUTPUT_ARCH(armv7e-m)

...linking fails with many EABI version mismatches errors:
arm-none-eabi-ld: error: source object main.o has EABI version 5, but target
main_cm7.elf has EABI version 0
arm-none-eabi-ld: failed to merge target specific data of file main.o

The linking fails with GNU-ld, but works when I use GNU-gold instead. An ARM
developer community member has also confirmed this behavior.

Affected version:
2.36.1.20210621

$ arm-none-eabi-ld --version
GNU ld (GNU Arm Embedded Toolchain 10.3-2021.07) 2.36.1.20210621

I currently haven't build GNU ld from the actually source code, so I don't know
if these issues are known or already fixed. Will make up this later. The tried
version was the binary build from the ARM homepage.

References:
ARM developer Community:
https://community.arm.com/support-forums/f/compilers-and-libraries-forum/52304/arm-none-eabi-ld-cannot-set-target-architecture

StackOverflow:
https://stackoverflow.com/questions/71188898/gnu-ld-warn-about-mismatching-arm-architecture-version

-- 
You are receiving this mail because:
You are on the CC list for the bug.