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Re: [PATCH] obvious pattern fix in gdb.base/step-line.exp


On Fri, Apr 17, 2009 at 07:06:09PM +0200, Christophe LYON wrote:
> However, from GDB, using "maintenance print symbols", I noticed that  
> quite a few lines have become "0" instead of meaningful values. In turn,  
> I thinks this makes skip_prologue do something wrong.
>
> What I dont' understand currently is where those "0" line entries come  
> from? Is there any verbose flag or maintenance command I could use to  
> understand how the Dwarf debug_line info is parsed?

Not really, but it's pretty straightforward to step through.

GDB uses line 0 internally to represent a lack of line number
information.  This is required because the line table uses
half-ranges; a line number and a start address.  We get a line
0 at file switch events or at DW_LNS_end_of_sequence.  There's
some hairy bits to make sure the 0 appears 'before' any other line
marker at the same address.

-- 
Daniel Jacobowitz
CodeSourcery


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