Re: [PATCH] libdw: Search for the last matching address with dwarf_getsrc_die.

[Josh Stone <jistone at redhat dot com>]

On 01/12/2015 01:25 PM, Mark Wielaard wrote:
> On Sat, 2014-12-27 at 16:49 +0100, Mark Wielaard wrote:
>> I think you are right and those tests, addrscopes and funcscopes, are
>> wrong. They use dwfl_module_getsrc to find the line associated with start
>> and end of the scope. But for the end they use the value of the high_pc
>> attribute. The high_pc attributes indicates the first address beyond
>> the current scope of the associated DIE. So the tests should use
>> highpc - 1 as end of scope.
>>
>> I created a patch to change dwfl_module_getsrc to not match against
>> a line with end_sequence set, changed the tests to use highpc -1.
>> And adjusted this patch for dwarf_getsrc_die. to match the new
>> behavior. Do those changes look correct to you?
> 
> Those are the following 2 commits on the mjw/pending branch:

Both look good to me.

> commit f5ea852c13d94fc04cdbd1d49c9185246d78fc62
> Author: Mark Wielaard <mjw@redhat.com>
> Date:   Wed Dec 24 13:17:23 2014 +0100
> 
>     libdw: Search for the last matching address with dwarf_getsrc_die.
>     
>     In commit 7d9b5a dwfl_module_getsrc was changed so that it returns the last
>     line record <= addr, rather than returning immediately on a match. This
>     changes dwarf_getsrc_die to do the same. And it adds a new test that checks
>     this by comparing against the same results from eu-addr2line (which uses
>     dwfl_module_getsrc) using dwarf_addrdie and dwarf_getsrc_die instead.
>     
>     Signed-off-by: Mark Wielaard <mjw@redhat.com>
> 
> commit bc000d1b457dfec65c20d43abd0dcc634f2e43cb
> Author: Mark Wielaard <mjw@redhat.com>
> Date:   Sat Dec 27 16:16:29 2014 +0100
> 
>     libdwfl: dwfl_module_getsrc should never match end_sequence line.
>     
>     The line with end_sequence set has an address outside the current line
>     sequence. An end_sequence line has no other useful information except
>     marking the address as out of range.
>     
>     Two tests, addrscopes and funcscopes, depended on matching the end_sequence
>     line. But that was because they included the high_pc address in the scope.
>     However the high_pc attributes has as address the first location past the
>     range associated with a given DIE. Adjust the tests to use high_pc - 1 as
>     end of the scope.
>     
>     Signed-off-by: Mark Wielaard <mjw@redhat.com>
>