[llvm-commits] [llvm] r163339 - in /llvm/trunk/lib: CodeGen/ CodeGen/SelectionDAG/ Target/X86/

[Chandler Carruth]

On Fri, Sep 7, 2012 at 3:52 PM, Duncan Sands <baldrick at free.fr> wrote:

> On 07/09/12 20:36, Bill Wendling wrote:
>
>> On Sep 7, 2012, at 9:38 AM, Duncan Sands <baldrick at free.fr> wrote:
>>
>>  Hi Craig,
>>>
>>> On 07/09/12 18:18, Craig Topper wrote:
>>>
>>>> Wouldn't dead code stripping in the linker have removed these from a
>>>> released build?
>>>>
>>>
>>> good question, but it seems not since I regularly use these when
>>> debugging
>>> release build problems on linux (usually buildbot crashes).  (I don't
>>> have
>>> time to look into why they aren't removed right now, sorry).  If it was
>>> the
>>> case that the linker removes them then Manman's patch wouldn't really be
>>> needed :)
>>>
>>>  If you need them, then we should think of another method for removing
>> them that works for us but doesn't affect your stuff.
>>
>> Manman, what do you think of having a flag, say REMOVE_DUMP, instead of
>> using NDEBUG?
>>
>
> how about removing them when doing a build with no debug symbols, i.e.
> rather
> than conditioning on the presence of checks (NDEBUG), condition on the
> presence
> of debug info.  If there is no debug info then even I am not going to be
> calling these guys from the debugger, debugging is just too hard without
> debug
> info!  (The buildbots I get to debug from time to time are built as
> release-
> with-debug-info).
>

I actually think NDEBUG makes a lot of sense here though... Debugging is
also too hard without asserts! ;]

What makes the most sense to me is this:

1) Have a specific #define which will always enable the dump methods. I'll
call it "LLVM_ENABLE_DUMP".
2) If not defined in the build, default this flag based on NDEBUG -> if
!NDEBUG #define it to 1.

This would allow you to configure your buildbots with -DLLVM_ENABLE_DUMP
Duncan if you wanted, or allow a normal dev to rebuild with that flag if
there is a bug that cannot be reproduced with asserts enabled. It would
keep these methods available for typical Release+Asserts builds. It would
remove them from typical actual released binaries.
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