Re: [Qemu-devel] [PATCH 18/20] tcg: Save insn data and use it in cpu_restore_state_from_tb

[Sergey Fedorov]

On 11.09.2015 13:32, Peter Maydell wrote:
> On 11 September 2015 at 11:29, Sergey Fedorov <address@hidden> wrote:
>> On 10.09.2015 16:49, Peter Maydell wrote:
>>>> @@ -2406,6 +2411,8 @@ static inline int tcg_gen_code_common(TCGContext *s,
>>>>>          check_regs(s);
>>>>>  #endif
>>>>>      }
>>>>> +    tcg_debug_assert(num_insns >= 0);
>>> This is claiming that every TB will have at least one insn_start,
>>> right? I think that most targets will violate that in the breakpoint
>>> case, because the "if we have a bp for this insn then generate a
>>> debug insn and break out of the loop" code is before the call
>>> to tcg_gen_insn_start().
>>>
>>> We should probably assert that num_insns < TCG_MAX_INSNS while
>>> we're here.
>>>
>> BTW, such skipping of instruction generation seems to be the cause of
>> getting a confusing "Disassembler disagrees with translator over
>> instruction" message in qemu log.
> ...I'd been meaning to try to track down what was provoking that :-)

Seems it was wrong pc increment when handling a fired breakpoint.

Best,
Sergey