[PATCH] [dwarfdump] Implement extraction of file information referenced in .debug_info.

[David Blaikie]

On Thu, Sep 4, 2014 at 8:53 AM, Frédéric Riss <friss at apple.com> wrote:

>
> On 04 Sep 2014, at 17:40, David Blaikie <dblaikie at gmail.com> wrote:
>
>
>
>
> On Thu, Sep 4, 2014 at 8:32 AM, Frédéric Riss <friss at apple.com> wrote:
>
>>
>> On 04 Sep 2014, at 17:19, David Blaikie <dblaikie at gmail.com> wrote:
>>
>>
>>
>>
>> On Thu, Sep 4, 2014 at 6:55 AM, Frederic Riss <friss at apple.com> wrote:
>>
>>> Hi dblaikie, echristo, aprantl,
>>>
>>> This is the merge of 2 patches:
>>>
>>> Pass the DWARFUnit to DWARFDebugLine::getFileNameByIndex().
>>>
>>> This way it can query the compilation dir when it is referenced (when a
>>> file references directory index 0, it refers to the compilation dir).
>>>
>>
>> Alternatively (Though not necessarily better - open to
>> opinions/preferences) DWARFUnit could have a wrapper for getFileNameByIndex
>> and could be returned a zero/default/something that the DWARFUnit could
>> detect and return the CU.
>>
>> Or the DWARFDebugLine could be constructed with its unit, or just with
>> the comp_dir of its unit so it didn't have to be passed in/queried for on
>> every lookup?
>>
>>
>> I’m currently working on an alternative where I turn
>> DWARFContext.cpp::getFileNameForUnit() and getFileLineInfoForCompileUnit()
>> into LineTable methods. This way I reduce code duplication with what I’ve
>> added to DWARFDebugInfoEntry::dump. I’ll see how that turns out.
>>
>>
>>> and:
>>>
>>> [dwarfdump] Implement extraction of file information referenced in
>>> .debug_info.
>>>
>>> This patch pretty prints the contents of the DW_AT_decl_file,
>>> DW_AT_call_file, DW_AT_decl_line and DW_AT_call line attributes.
>>> Drop the const on the passed DWARFUnit to be able to call
>>> getLineTableForUnit (the line table construction is lazy, thus the getter
>>> might modify the Unit).
>>>
>>
>> What pretty printing occurs for lines? (obviously for files this would
>> allow you to print the file name rather than the file number - but
>> DW_AT_decl/call_line already contain the line number, right?)
>>
>>
>> It’s just that they’re printed as decimal numbers. Which is indisputably
>> more pretty for line numbers :-)
>>
>
> Agreed - though should we just print numbers as decimal generally? Which
> numbers benefit from being printed as hex I wonder?
>
>
> All unsigned Forms get printed as hex by FormValue. As this covers
> addresses for example, I wouldn’t call that a bad choice. In fact, I can’t
> come up right now with another attribute I’d like to see printed as decimal
> (but I’m sure there are some).
>

You can probably add DW_AT_lower_bound, DW_AT_upper_bound, and DW_AT_count
to the list of attributes that might make more sense as (signed) decimal.
(just something I came across in a test case)


>
> (might be worth splitting the line number part of the patch out - it might
> be easier (as you say, it's simply printing them as decimal rather than hex
> - doesn't depend on access to the line table you're adding here, etc) or it
> might be harder/different (if we end up changing the default & trying to
> decide if there are places where that new default would be problematic,
> etc))
>
>
> I’ll do that once I finish the current rework.
>
> Fred
>
>
>> Fred
>>
>>
>>> http://reviews.llvm.org/D5192
>>>
>>> Files:
>>>   lib/DebugInfo/DWARFContext.cpp
>>>   lib/DebugInfo/DWARFDebugInfoEntry.cpp
>>>   lib/DebugInfo/DWARFDebugInfoEntry.h
>>>   lib/DebugInfo/DWARFDebugLine.cpp
>>>   lib/DebugInfo/DWARFDebugLine.h
>>>   test/DebugInfo/X86/2011-09-26-GlobalVarContext.ll
>>>   test/DebugInfo/X86/fission-cu.ll
>>>   test/DebugInfo/namespace.ll
>>>   test/MC/MachO/gen-dwarf.s
>>>
>>
>>
>>
>
>
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