MBlaze disassembler: UNREACHABLE executed at MBlazeRegisterInfo.cpp:179

[llvmbot]

Bugzilla Link	9653
Resolution	FIXED
Resolved on	Apr 11, 2011 16:58
Version	trunk
OS	Linux
Reporter	LLVM Bugzilla Contributor

Extended Description

This is trunk r129111 running on Debian x86-64.

I get

$ echo '0x95 0x80 0x96' |llvm-mc --disassemble --triple=mblaze
Unknown register number!
UNREACHABLE executed at MBlazeRegisterInfo.cpp:179!
0 llvm-mc 0x0000000000d9838f
1 llvm-mc 0x0000000000d98eca
2 libpthread.so.0 0x00007fb4a62a3f60
3 libc.so.6 0x00007fb4a55c0165 gsignal + 53
4 libc.so.6 0x00007fb4a55c2f70 abort + 384
5 llvm-mc 0x0000000000d82684
6 llvm-mc 0x00000000004378f0
7 llvm-mc 0x000000000042ae04
8 llvm-mc 0x0000000000408903
9 llvm-mc 0x0000000000409c1f
10 llvm-mc 0x000000000040c762
11 libc.so.6 0x00007fb4a55acc4d __libc_start_main + 253
12 llvm-mc 0x0000000000406e29
Stack dump:
0. Program arguments: llvm-mc --disassemble --triple=mblaze
Aborted

[llvmbot]

And in case you wonder, this also happens with full four bytes (add e.g. 0x00 to the end).

[llvmbot]

What instruction is this suppose to be? From my manual decoding the instruction is "MFS R12, 0x1600" with 0x1600 being an undefined special purpose register. Perhaps crashing is not the best option here but it is currently by design.

[llvmbot]

Well, other backends seem to emit an "undefined". Crashing on invalid instructions is unhelpful in that it can prevent disassembling a blob that has mostly code and a few bytes of data that happens to contain an invalid instruction...

[llvmbot]

This should be fixed in 129303.