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Re: When is the stack pointer unreliable?
- To: law at cygnus dot com
- Subject: Re: When is the stack pointer unreliable?
- From: John Wehle <john at feith dot com>
- Date: Sun, 6 Sep 1998 21:23:24 -0400 (EDT)
- cc: egcs at cygnus dot com
>> Since reloading the stack pointer causes a stall on some processors
>> it should be avoided when possible. Under what situations is sp
>> unreliable?
> alloca calls,
In which case current_function_calls_alloca is set.
> variable sized objects in the stack come immediately to mind.
I assume that this is always handled by allocate_dynamic_stack_space
in which case current_function_calls_alloca is set.
> You might also need to check if the compiler has optimized away
> popping of args after a function call if we unconditionally reach the
> epilogue after performing the call.
Good point. That hadn't occurred to me.
-- John
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