[llvm-dev] lld/coff section name .debug_str is longer than 8 characters

Martin Storsjö via llvm-dev llvm-dev at lists.llvm.org
Tue Dec 17 23:46:10 PST 2019

On Wed, 18 Dec 2019, Carlo Kok wrote:

> On Wed, Dec 18, 2019, at 08:11, Martin Storsjö wrote:
>> On Wed, 18 Dec 2019, Carlo Kok via llvm-dev wrote:
>>> Since updating today I get: section name .debug_str is longer than 8
>>> characters and will use a non-standard string table
>>> This is LLD + Coff/DWARF; Is this now unsupported, am I doing something
>>> wrong or something else? Alternatively, what can I do to hide it?
>> The warning itself is harmless and doesn't indicate any other behaviour
>> change. It was prompted when MSVC's dumpbin.exe suddenly started
>> erroring
>> out on such object files since MSVC 2019 16.2, but that does seem to be
>> a
>> bug that is going to be fixed (see
>> https://developercommunity.visualstudio.com/content/problem/777863/dumpbin-regression-in-since-toolset-1422.html).
>> As the dumpbin errors only was a regression and not an intentional change
>> (and the bug is marked as "fix pending"), maybe the warning should be
>> reverted?
>> In the meantime, to silence it, you could add the -lldmingw flag, as the
>> warnings isn't printed in MinGW environments (where DWARF debug info is
>> expected and the default). That will opt in to a few other MinGW
>> compatibility behaviours though, but they shouldn't really be fatal
>> (unless you explicitly want to make DLLs with no exported symbols at all).
> Thanks. Reading the LLD source, it looks like it does quite a few things. Wouldn't /debug:dwarf be a better option for this?

Yeah, it does a few things, but unless your code actually contains 
anything that needs it, most of it shouldn't really have any effect. (You 
will have the visible effect of adding a couple synthesized symbols and 8 
bytes of data in .rdata though.)

But it's indeed not the right permanent solution.

Silencing the warning with /debug:dwarf in addition to /lldmingw sounds 
sensible to me, if we really want to keep the warning despite MSVC fixing 
the dumpbin issue.

// Martin

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