[PATCH 2/6] Delegate opcodes to select disassembler in GDB

[Yao Qi]

"Maciej W. Rozycki" <macro@imgtec.com> writes:

>  This change causes an assertion failure when trying to disassemble a 
> MIPS16 function:
>
> (gdb) disassemble main
> Dump of assembler code for function main:
>    0x00400209 <+0>:
> .../gdb/arch-utils.c:979: internal-error: int default_print_insn(bfd_vma, disassemble_info*): Assertion `info->mach == bfd_get_mach (exec_bfd)' failed.
> A problem internal to GDB has been detected,
> further debugging may prove unreliable.
> Quit this debugging session? (y or n)

Sorry about that.  I did deliberately run
testsuite/gdb.base/all-architectures-[0-7].exp tests to cover the case
that using disassembler for each architecture.  It covers mips, but it
doesn't cover mips16 and micromips.

>
> This is because `info->mach' is 16 (the `bfd_mach_mips16' aka `mips:16' 
> BFD) whereas `bfd_get_mach (exec_bfd)' is 33 (the `bfd_mach_mipsisa32r2' 
> aka `mips:isa32r2' BFD).  This is expected for MIPS16 code within a 
> program that has been built for the MIPS32r2 ISA; see 
> `gdb_print_insn_mips' for the origin.
>
>  So what's the purpose of this assertion?

The assertion is based on assumption that "info->mach" is got from
bfd_get_mach (exec_bfd), but it is not right for mips16.  We can remove
this line.  If you agree, I'll post a patch to remove this line.

-- 
Yao (齐尧)