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Re: Order "begin" probes are run


"Stone, Joshua I" <joshua.i.stone@intel.com> writes:

> [...]  Well, I implemented the check for negative in parse_literal,
> which is near the bottom of the parsing stack.  [...]  If you can
> think of a test case where this fails, please let me know. [...]

I couldn't find a problem case with a few minutes' effort, so OK.

> [...]  Even changing [global initialization] to begin(-2^63) isn't
> really correct, as it should happen *before* the beginning.  [...]

-2^63 is not actually a bad choice, and easily documented.  The more
interesting ordering conflict is between this and
module-parameter-based initialization.

By the way, the new parse_literal variant does not check for numeric
overflow for negative numbers quite right (running on x86-64):

% ./stap -p1 -e 'probe begin(-9223372036854775808),begin(-9223372036854775809) {}'
# parse tree dump
# file <input>
probe begin(-9223372036854775808),
begin(9223372036854775807){
}

- FChE


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