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From: Richard Henderson <rth@twiddle.net>
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Subject: Re: [Qemu-devel] [PATCH 03/16] tcg: Propagate args to op->args in
 tcg.c
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To: =?UTF-8?Q?Alex_Benn=c3=a9e?= <alex.bennee@linaro.org>
Cc: qemu-devel@nongnu.org, aurelien@aurel32.net

On 06/26/2017 08:02 AM, Alex Bennée wrote:
>>   #if TARGET_LONG_BITS > TCG_TARGET_REG_BITS
>> -                a = ((target_ulong)args[i * 2 + 1] << 32) | args[i * 2];
>> +                a = deposit64(op->args[i * 2], 32, 32, op->args[i * 2
>>               + 1]);
> 
> It doesn't now but should be assert against us overflowing the args
> buffer here when dealing with encoded data? Or should it have faulted
> when planting the ops?

Statically checked via preprocessor in tcg/tcg-op.h:

#elif TARGET_INSN_START_WORDS == 3
...
#else
# error "Unhandled number of operands to insn_start"
#endif

which maxes out at 6 host arguments, which is less than MAX_OPC_PARAM.


r~