[Dwarf-discuss] dwarf ver3.0: prologue_end and epilogue_begin bits

Chris Quenelle Chris.Quenelle@Sun.COM
Tue May 22 17:47:24 GMT 2007


It seems like you are taking the assembly output of the compiler
and trying to figure out how to convert the information
into dwarf.  Is that right?

If the compiler is emitting .dbline directives that contain
no information about actual line numbers (0, -1, -2) then I would
assume such .dbline directives should not have any effect
on the line number.  That means the instructions that
follow ".dbline 0" should be assigned the same line
number as the instructions that come before the ".dbline 0".
It's a no-op as far as the line number information is concerned.

It is possible to create a "blank spot" in the dwarf line number
table by using end_sequence.  But this blank spot cannot have
any prolog or epilog or any other flags assigned to those instructions,
because  the blank spot is not included in the line number table at all.

So it seems the only way to go is to use the last line number in
effect when you see a .dbline 0, .dbline -1, .dbline -2.


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