[lldb-dev] Linker error on fresh working copy

[Jason Molenda]

I added --enable-cxx11 to build-llvm.pl, removed my existing llvm-build directory, did a clean build with Xcode and I got a successful link.

The problem came up due to the changes in r195239.  When included in C++11 mode, SmallPtrSet.h calls a method in SmallPtrSet.cpp (in llvm).  llvm was being built in C++03 mode so the additional method wasn't emitted for SmallPtrSet.o; lldb included SmallPtrSet.h in C++11 mode so a reference to that function was emitted.

(just to state the obvious - I'm sure we were all on the same page here)



On Nov 22, 2013, at 6:42 PM, Félix Cloutier <felixcca at yahoo.ca> wrote:

> I'm building from Xcode, so I guess I need to change scripts/build-llvm.pl. Xcode reports this when I build:
> 
> % cd '/Users/felix/Projets/OpenSource/lldb/llvm-build/Release+Asserts/x86_64' && '/Users/felix/Projets/OpenSource/lldb/llvm/configure' --enable-targets=x86_64,arm --disable-terminfo --enable-cxx11 --enable-optimized --enable-assertions --enable-libcpp --build=x86_64-apple-darwin11
> 
> --enable-cxx11 is there, but even with that build completing successfully I still get the same error.
> 
> Félix
> 
> Le 2013-11-22 à 04:15:21, Arnaud A. de Grandmaison <arnaud.adegm at gmail.com> a écrit :
> 
>> On 11/22/2013 07:56 AM, Félix Cloutier wrote:
>>> Hello people,
>>> 
>>> I got the lldb source fresh from SVN, and even after doing the little Python dance for Mavericks (setting SDKROOT to macosx10.8 like Jason Molenda suggested yesterday), I still get compile errors. The linker bails out with this when it tries to link lldb-platform:
>>> 
>>> Undefined symbols for architecture x86_64:
>>>   "llvm::SmallPtrSetImpl::SmallPtrSetImpl(void const**, unsigned int, llvm::SmallPtrSetImpl&&)", referenced from:
>>>       llvm::SmallPtrSet<DWARFDebugInfoEntry const*, 4u>::SmallPtrSet(llvm::SmallPtrSet<DWARFDebugInfoEntry const*, 4u>&&) in liblldb-core.a(SymbolFileDWARF.o)
>>> ld: symbol(s) not found for architecture x86_64
>>> clang: error: linker command failed with exit code 1 (use -v to see invocation)
>>> 
>>> Looking deeper, I found that it is declared like that:
>>> 
>>> #if LLVM_HAS_RVALUE_REFERENCES
>>>   SmallPtrSetImpl(const void **SmallStorage, unsigned SmallSize,
>>>                   SmallPtrSetImpl &&that);
>>> #endif
>>> 
>>> Could it be that llvm is built without LLVM_HAS_RVALUE_REFERENCES but lldb is built with it?
>>> 
>> 
>> Hi Felix,
>> 
>> I also got this problem. It comes from the fact that lldb is built in c++11 mode (required), whereas your llvm codebase is built without. You should compile llvm in c++11 as well, or some functions will simply not be in the libraries.
>> 
>> If your are using cmake, I submitted (but diid not commit) a patch to optionally enable c++11 building with cmake a few hours ago on the llvm-commit list. For an autoconf build, there is an --enable-cxx11 to configure.
>> 
>> Cheers,
>> --
>> Arnaud
>> 
>>> Félix
>>> 
>>> 
>>> _______________________________________________
>>> lldb-dev mailing list
>>> 
>>> lldb-dev at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
>> 
>> 
>> -- 
>> Arnaud A. de Grandmaison
>> 
> 
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