gdb fails to disassemble RV64 instructions about riscv-binutils-gdb HOT 5 CLOSED

Thanks! I'm actually not sure right now how to compile gdb myself — when I get that working I'll get back to you.

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When you get a chance, can you confirm that 9a8cb24 fixes gdb?

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@aswaterman This is half fixed in 1cc4048 (it looks like there was a big rebase earlier and I can't easily tell what has been changed since that commit). Specifically, set arch riscv:rv64 now works, but gdb still isn't automatically picking up the bitness from the ELF file. (I ran gdb against a ld.so file, then did disas _start)

EDIT: this test was done on gdb as built by riscv-collab/riscv-gnu-toolchain@f670e2f5

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Thanks for the update. I don't have the time to look into the ELF class detection issue; ideally one of the people working on GDB could do so.

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This has had no comment for almost a year. I am unable to reproduce the gdb problem using a toolchain built today.

Bisecting on the riscv-gnu-toolchain project narrowed the fix down between these two commits
commit 5dac17852d746f6ea26736a7cdbd073b201ce08f
Author: Palmer Dabbelt [email protected]
Date: Wed May 3 23:56:31 2017 -0700
and
commit 19ddd4d6f42bddaa29a76f926fea9ee5be177766
Merge: ef9bf99 43a55a8
Author: Palmer Dabbelt [email protected]
Date: Wed May 3 22:36:55 2017 -0700

Then looking at riscv-binutils-gdb git log the fix was obvious.
commit d6f218e
Author: Kuan-Lin Chen [email protected]
Date: Tue Jan 17 09:46:28 2017 +0800

RISC-V/bfd: Hook elf_backend_object_p to set the mach type.

I did builds before and after to verify that this commit fixes it. So closing.

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