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Re: [PATCH] libdw: Search for the last matching address with dwarf_getsrc_die.
- From: Josh Stone <jistone at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Thu, 15 Jan 2015 11:54:37 -0800
- Subject: Re: [PATCH] libdw: Search for the last matching address with dwarf_getsrc_die.
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>
>