.debug_loc

[Michal Ludvig <mludvig@suse.cz>]

Hi Daniel,
I have a question on parsing .debug_loc on x86-64. Let's have this one:

         .section        .debug_loc,"",@progbits
.LLST0:
         .quad   .LVL3-.text     # Location list begin address (*.LLST0)
         .quad   .LVL5-.text     # Location list end address (*.LLST0)
         .value  0x1     # Location expression size
         .byte   0x53    # DW_OP_reg3
         [...]
         .quad   .LVL16-.text    # Location list begin address (*.LLST0)
         .quad   .Letext0-.text  # Location list end address (*.LLST0)
         .value  0x1     # Location expression size
         .byte   0x53    # DW_OP_reg3
         .long   0x0     # Location list terminator begin (*.LLST0)
         .long   0x0     # Location list terminator end (*.LLST0)
.LLST1:
         .quad   .LVL10-.text    # Location list begin address (*.LLST1)
         .quad   .LVL11-.text    # Location list end address (*.LLST1)
         [...]

As you can see, addresses of ranges are 64b (.quad) BUT the terminating 
zeroes are only 32b long (.long). Is it an intent or a bug? If it's 
correct, than how do I realise that I've reached the end of LLST0? Maybe 
because the address (.long+.long = .quad = 0) is lower that any of the 
previous ones? I can't tell that I'm at the end if I just see a NULL 
address, because IMHO it's perfectly correct for a range to start at the 
very beginning of .text section. Is it a bug or not?

And one more thing - how do I distinguish whether a given DIE has the 
attribute "in-place" or linked in .debug_loc? The only difference I 
could find was the appropriate record for DW_AT_location in 
.debug_abbrev, where for "in-place" case was the value DW_FORM_blockN 
while for loclist entries it was DW_FORM_data4. Can I rely on this fact 
or is there a better way to differentiate these cases?
BTW Is it correct to have the pointer as DW_FORM_data4 and not as 
DW_FORM_data8 even on 64b machine?

Thanks for information.

Michal Ludvig
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