Paranoid NOP padding?

[Bernd Jendrissek]

Looking for some 80386 timings (32-bit div in real mode), I came across
this:

http://www.microsoft.com/msj/0698/hood0698.aspx

It seems gas fills gaps created by .align N with NOP instructions, such
that if the CPU reaches the beginning (!) of the gap, it skips over it
without any state change other than for %eip.

Sometimes, though, the CPU should *never* execute code in a "gap".
Think gaps between functions, for example.

Could it be cool to teach gas (or is ld the better place?) to insert
0xcc (debugger traps) instead, or even one of the guaranteed-invalid
opcodes (if there are any that are 1 byte long)?

I suppose I'm supposed to show the patch now... :)

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