[PATCH] x86 interrupt attribute

Mike Stump mikestump@comcast.net
Wed Sep 30 00:47:00 GMT 2015


On Sep 29, 2015, at 3:10 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Tue, Sep 29, 2015 at 2:23 PM, Mike Stump <mikestump@comcast.net> wrote:
>> On Sep 29, 2015, at 1:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> commit f3a6675a8d69d810d2cad0c090a762094a0a8622
>>> Author: H.J. Lu <hjl.tools@gmail.com>
>>> Date:   Tue Sep 29 13:47:18 2015 -0700
>>> 
>>>   Define EPILOGUE_USES in i386 so that all preserved registers are used
>>>   by the epilogue of interrupt handler.  Don't explicitly mark BP and SP
>>>   registers as used since they are always used in epilogue.
>>> 
>>> Please take a look.
>> 
>> Oh, too bad you didn’t copy it here.  The easiest thing to blow is the addition of reload_completed && on the condition


> static bool
> ix86_save_reg (unsigned int regno, bool maybe_eh_return)
> {
>  /* In interrupt handler, we don't preserve MMX and x87 registers
>     which aren't supported when saving and restoring registers.  No
>     need to preserve callee-saved registers unless they are modified.
>     We also preserve all caller-saved registers if a function call
>     is made in interrupt handler since the called function may change
>     them.  Don't explicitly save BP and SP registers since they are
>     always preserved.  */
>  if (cfun->machine->is_interrupt)
>    return ((df_regs_ever_live_p (regno)
>             || (call_used_regs[regno] && cfun->machine->make_calls))
>            && !fixed_regs[regno]
>            && !STACK_REGNO_P (regno)
>            && !MMX_REGNO_P (regno)
>            && regno != BP_REG
>            && regno != SP_REG
>            && (regno <= ST7_REG || regno >= XMM0_REG));
> 
> Is this sufficient?

I see no string "reload_completed &&”.  Either, you need it here, or, you need it in the caller.


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