[cfe-dev] rfc: Adding a mode to -gline-tables-only to include parameter names, namespaces

[Nico Weber]

On Wed, Apr 29, 2015 at 12:35 PM, Reid Kleckner <rnk at google.com> wrote:

> On Wed, Apr 29, 2015 at 12:25 PM, Nico Weber <thakis at chromium.org> wrote:
>
>> Hi,
>>
>> the motivation for -gline-tables-only was to make debug info much
>> smaller, but still include enough to get usable stack frames [1]. We
>> recently tried using it in Chromium and discovered that the stack frames
>> aren't all that usable: Function parameters disappear, as do function
>> namespaces.
>>
>> Are there any concerns about adding a mode to -gline-tables-only (or a
>> second flag -gline-tables-full, or similar) that includes function
>> parameter info and namespace info but still omits most debug info?
>>
>> (Background: We rely on dsym files to let our crash server symbolize
>> crash dumps we get from the wild. dsymutil uses debug info, but it
>> apparently crashes if debug info is > 4GB. We hit that recently. So we
>> started using -gline-tables-only, but now all our stacks are close to
>> unusable, even though the motivation for gline-tables-only was to still
>> have usable stacks. We can't easily use symbol names as they get stripped
>> very early in our pipeline, and changing that is apparently involved.)
>>
>
> Is there some way to change the pipeline to use the mangled name stored in
> .symtab instead of the DW_AT_name in the DWARF? My understanding is that
> the sanitizers already do this.
>

See "We can't easily use symbol names as they get stripped very early in
our pipeline." above – from what I understand, one machine does the build,
strips, runs dsymutil to get a .dSYM bundle, and then that is shipped to
the crash servers.
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