Make a new 14.2.0-2 release with binutils 2.43

[ilg-ul]

#33

[matsobdev]

New release fails to compile Pico 2 binary when pico_riscv_gcc_zcb_zcmp:

mateush@mateush:~/Dysk RAM/pico2$ cmake - S "~/Dysk RAM/pico2" -B "~/Dysk RAM/pico2/build"
PICO_SDK_PATH is /home/mateush/pico-sdk-2.0.0
Target board (PICO_BOARD) is 'pico2'.
Using board configuration from /home/mateush/pico-sdk-2.0.0/src/boards/include/boards/pico2.h
Pico Platform (PICO_PLATFORM) is 'rp2350-riscv'.
Configuring toolchain based on PICO_COMPILER 'pico_riscv_gcc_zcb_zcmp'
-- The C compiler identification is GNU 14.2.0
-- The CXX compiler identification is GNU 14.2.0
-- The ASM compiler identification is GNU
-- Found assembler: /home/mateush/xpack-riscv-none-elf-gcc-14.2.0-2/bin/riscv-none-elf-gcc
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /home/mateush/xpack-riscv-none-elf-gcc-14.2.0-2/bin/riscv-none-elf-gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /home/mateush/xpack-riscv-none-elf-gcc-14.2.0-2/bin/riscv-none-elf-g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
Build type is Release
-- Found Python3: /usr/bin/python3.8 (found version "3.8.10") found components: Interpreter 
TinyUSB available at /home/mateush/pico-sdk-2.0.0/lib/tinyusb/src/portable/raspberrypi/rp2040; enabling build support for USB.
BTstack available at /home/mateush/pico-sdk-2.0.0/lib/btstack
cyw43-driver available at /home/mateush/pico-sdk-2.0.0/lib/cyw43-driver
lwIP available at /home/mateush/pico-sdk-2.0.0/lib/lwip
mbedtls available at /home/mateush/pico-sdk-2.0.0/lib/mbedtls
-- Configuring done
-- Generating done
-- Build files have been written to: /home/mateush/Dysk RAM/pico2/build
mateush@mateush:~/Dysk RAM/pico2$ cd build
mateush@mateush:~/Dysk RAM/pico2/build$ make -j 2
Scanning dependencies of target bs2_default
[  1%] Building ASM object pico-sdk/src/rp2350/boot_stage2/CMakeFiles/bs2_default.dir/compile_time_choice.S.obj
[  2%] Linking ASM executable bs2_default.elf
[  2%] Built target bs2_default
Scanning dependencies of target bs2_default_padded_checksummed_asm
[  3%] Generating bs2_default.bin
[  5%] Generating bs2_default_padded_checksummed.S
[  5%] Built target bs2_default_padded_checksummed_asm
Scanning dependencies of target project_name
[  6%] Building C object CMakeFiles/project_name.dir/home/mateush/pico-sdk-2.0.0/src/rp2_common/pico_stdlib/stdlib.c.obj
[  7%] Building C object CMakeFiles/project_name.dir/file_name.c.obj
[  9%] Building C object CMakeFiles/project_name.dir/home/mateush/pico-sdk-2.0.0/src/rp2_common/hardware_gpio/gpio.c.obj
/tmp/ccIIufYr.s: Assembler messages:
/tmp/ccIIufYr.s:1608: Error: unrecognized opcode `cm.mvsa01 s0,s1'
make[2]: *** [CMakeFiles/project_name.dir/build.make:108: CMakeFiles/project_name.dir/home/mateush/pico-sdk-2.0.0/src/rp2_common/hardware_gpio/gpio.c.obj] Błąd 1
make[2]: *** Oczekiwanie na niezakończone zadania....
make[1]: *** [CMakeFiles/Makefile2:2161: CMakeFiles/project_name.dir/all] Błąd 2
make: *** [Makefile:103: all] Błąd 2
mateush@mateush:~/Dysk RAM/pico2/build$

That seems important: /tmp/ccIIufYr.s:1608: Error: unrecognized opcode `cm.mvsa01 s0,s1'. No wonder it is opcode from _zcmp extension. Both pico_riscv_gcc and extra pico_riscv_gcc_zcb compiles fine.

PS. Build type set to Debug allows compilation to complete, but I guess it doesn't use potential of _zcmp instructions then...

[ilg-ul]

Hmmm... The 14.2.0-2 build uses the latest official gcc and the latest official binutils, I don't know what else to do to make it work. :-(

Frankly, I lost track of all these RISC-V extensions, and I don't know how well GCC supports them.

Do you have any suggestions?

[ilg-ul]

@TommyMurphyTM1234, it looks like the Zcmp implementation still has some issues.

[TommyMurphyTM1234]

@TommyMurphyTM1234, it looks like the Zcmp implementation still has some issues.

Maybe @kito-cheng might be able to comment and clarify what version of Binutils supports the Zcmp extension cm.mv* instructions?

I can't see at a glance if/when this patch was integrated:

• https://sourceware.org/pipermail/binutils/2024-February/132263.html

This patch supports Zcmp instruction 'cm.mva01s' and 'cm.mvsa01'.

Edit: that patch seems to be integrated into the master branch of Binutils:

• https://github.com/bminor/binutils-gdb/blob/9772824e0e34a8e521559c448cce8f3e75b67fe7/gas/config/tc-riscv.c#L1626-L1648

but not the binutils-2_43-branch branch:

• https://github.com/bminor/binutils-gdb/blob/04cb3ca037690e0dfc5f9a36defbe6725bc8b639/gas/config/tc-riscv.c#L1622-L1641

[ilg-ul]

I cannot see these changes in the 2.43.1 source either. So the latest binutils release includes only partial support for the Zcmp extension?

@kito-cheng, can you confirm this?

[matsobdev]

I'm fresh to all that RISC-V, so can not cast more light on it, but CORE-V compiler, 30 May 2024 does work. It is GCC 14.1.0. 22 Jun 2023 - GCC 12 something works as well. It's not any clue, but seems to be problems with _zcmp on a stable version, as RPi forum says.

[TommyMurphyTM1234]

I'm fresh to all that RISC-V, so can not cast more light on it, but CORE-V compiler, 30 May 2024 does work. It is GCC 14.1.0. 22 Jun 2023 - GCC 12 something works as well. It's not any clue, but seems to be problems with _zcmp on a stable version, as RPi forum says.

I think that the problem is clear. The patch to add support for the Zcmp extension's cm.mv* instructions to the Binutils assembler is on the master branch of Binutils but not in any released version up to and including 2.43.1. I presume that other toolchains that don't have a problem with these instructions are built with the necessary patch to Binutils and maybe from the Binutils master branch. Until this patch is promoted to a released version of Binutils I don't think that @ilg-ul can do much since he prefers to build from released sources/tarballs only (which is a judicious choice from a stability/predictability point of view).

[ilg-ul]

but CORE-V compiler, 30 May 2024 does work.

I did not check the build scripts, but I expect top-of-tree to mean the very latest commits, not the stable releases.

[kito-cheng]

I cannot see these changes in the 2.43.1 source either. So the latest binutils release includes only partial support for the Zcmp extension?

@kito-cheng, can you confirm this?

That's kinda epic mistake...we only merge partial zcmp support within 2.43.1...full support just landed last week, which means not included in any release yet.

[1] bminor/binutils-gdb@ca2590d
[2] https://sourceware.org/bugzilla/show_bug.cgi?id=32036

[ilg-ul]

Thank you for clarifying this.

There will probably be a 14.2.0-3 after a new binutils release.

[TommyMurphyTM1234]

So, I guess that the GCC 14 release notes change log is misleading?

• https://gcc.gnu.org/gcc-14/changes.html

• Support for the following standard extensions has been added:
  • ...
  • Code size reduction extensions:
    • ...
    • Zcmp
    • ...