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Re: Using dwfl to enumerate frames of current thread


On Thu, 2015-08-20 at 10:06 -0700, Josh Stone wrote:
> On 08/20/2015 08:32 AM, Mark Wielaard wrote:
> > See Dwarf 4 2.17 Code Addresses and Ranges. In particular elfutils takes
> > advantage of:
> > "If an entity has no associated machine code, none of these attributes
> > are specified."
> 
> (A -> B) does not give you (B -> A)!
> 
> That is, the spec does *not* say "If none of these attributes are
> specified, the entity has no associated machine code."

Maybe the spec needs clarification that is what is actually meant. Or
you can see it as a quality of implementation issue. But it is what we
need and what we rely on. Otherwise you have no way to know whether or
not to scan a whole CU or DIE subtree for program scope DIEs. And always
scanning each and every subtree just in case some program scope DIE is
hiding deep down is just silly.

Cheers,

Mark

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