pcl_surface occur build error with certain Eigen versions

[UnaNancyOwen]

Build pcl_surface

PCL(pcl_surface) can't build with certain version of Eigen in Visual Studio.
These combination is follows Visual Studio versions and Eigen versions.

PCL(pcl_surface) master/HEAD e97b664

	Visual Studio 2013 Update5	Visual Studio 2015 Update1
Eigen 3.2.6	success	failure
Eigen 3.2.7	success	failure
Eigen 3.3.0 beta1	failure	success
Eigen 3.3.0 dev branch/HEAD (e97b664)	failure	success

[Error] Visual Studio 2015 Update1 + Eigen 3.2.7

c:\program files\eigen\include\eigen3\eigen\src\core\products\generalmatrixmatrix.h(62): fatal error C1001: INTERNAL COMPILER ERROR
c:\program files\eigen\include\eigen3\eigen\src\core\products\generalmatrixmatrix.h(62): fatal error C1001: INTERNAL COMPILER ERROR
cl : Command line error D8040: error creating or communicating with child process.

This error that caused in Eigen.
You can be solved by version up to Eigen 3.3.0.
This case is no problem.

[Error] Visual Studio 2013 Update5 + Eigen 3.3.0 beta1

error C2664: 'Eigen::aligned_allocator<U>::aligned_allocator(const Eigen::aligned_allocator<U> &)' : cannot convert parameter 1 from  'std::allocator<T>' to 'const Eigen::aligned_allocator<U> &'  C:\Program Files\Boost\include\boost-1_59\boost\unordered\detail\allocate.hpp   489
error C2664: 'Eigen::aligned_allocator<U>::aligned_allocator(const Eigen::aligned_allocator<U> &)' : cannot convert parameter 1 from 'std::allocator<T>' to 'const Eigen::aligned_allocator<U> &'   C:\Program Files\Boost\include\boost-1_59\boost\unordered\detail\allocate.hpp   489
error C2664: 'Eigen::aligned_allocator<U>::aligned_allocator(const Eigen::aligned_allocator<U> &)' : cannot convert parameter 1 from 'std::allocator<T>' to 'const Eigen::aligned_allocator<U> &'   C:\Program Files\Boost\include\boost-1_59\boost\unordered\detail\allocate.hpp   489

Maybe, I think this error that caused in PCL.
I don’t know the cause of error in this environment (PCL master/HEAD + Eigen 3.3.0 + Visual Studio 2013).

Do you have any ideas?

[taketwo]

Can you trace these errors to specific files/lines in PCL?

[UnaNancyOwen]

I can't put my finger on it, whether the error is occurred in files/lines of source code.
(sorry, lack my knowledge about c++)
However, It seems to be occurring in pcl_surface by look at the build log.
Please check it.

[taketwo]

Try to replace line 96 in "grid_projection.h" with:

typedef boost::unordered_map<int, Leaf, boost::hash<int>, std::equal_to<int>, Eigen::aligned_allocator<std::pair<const int, Leaf> > > HashMap;

Just yesterday I merged #1497 with a very similar fix.

[UnaNancyOwen]

I tried to replace and rebuild pcl_surface, but still occurred the same error.

[taketwo]

Please upload the new build log, there must be at least some difference.

[UnaNancyOwen]

Please check rebuild log and error message.

Error   58  error C2664: 'Eigen::aligned_allocator<U>::aligned_allocator(const Eigen::aligned_allocator<U> &)' : cannot convert argument 1 from 'std::allocator<T>' to 'const Eigen::aligned_allocator<U> &'    C:\Program Files\Boost\include\boost-1_59\boost\unordered\detail\allocate.hpp   489
Error   59  error C2664: 'Eigen::aligned_allocator<U>::aligned_allocator(const Eigen::aligned_allocator<U> &)' : cannot convert argument 1 from 'std::allocator<T>' to 'const Eigen::aligned_allocator<U> &'    C:\Program Files\Boost\include\boost-1_59\boost\unordered\detail\allocate.hpp   489
Error   60  error C2664: 'Eigen::aligned_allocator<U>::aligned_allocator(const Eigen::aligned_allocator<U> &)' : cannot convert argument 1 from 'std::allocator<T>' to 'const Eigen::aligned_allocator<U> &'    C:\Program Files\Boost\include\boost-1_59\boost\unordered\detail\allocate.hpp   489

[taketwo]

Hm, no idea. Looks like a very subtle bug raising from interaction between these specific versions of Boost, Eigen, and the compiler. With the change I proposed, it is definitely not a problem on PCL side. By the way, I discovered we had this bug reported already: #1266.

[UnaNancyOwen]

I tryed to replace to std::allocator, the build error was not occurred.
But, I can't say whether that is correct or not, because lack my knowledge about c++.

typedef boost::unordered_map<int, Leaf, boost::hash<int>, std::equal_to<int>, std::allocator<std::pair<const int, Leaf> > > HashMap;

Tell me what you think.

[UnaNancyOwen]

With the change I proposed, it is definitely not a problem on PCL side.

Okay, Thank you for debugging with me.

[taketwo]

std::allocator is what you get by default anyway (if you don's specify it at all). So what you wrote now is same as just:

typedef boost::unordered_map<int, Leaf, boost::hash<int>, std::equal_to<int> > HashMap;

Apparently, the intention of the author of GridProjection class was to have the Leaf objects allocated with alignment. If we drop this as you did, the compilation succeeds, but spurious segfaults may start happen in runtime, as it always happens with misaligned Eigen types. So, this is a way to make the compiler happy, however it potentially introduces bugs.

[UnaNancyOwen]

I was understanding that this way is wrong.
For now, I use Eigen 3.2.7 when building on Visual Studio 2013.
Thank you! :)

[UnaNancyOwen]

Eigen 3.2.8 has been released.
This version was confirmed to be able to build PCL(pcl_surface) on both Visual Studio 2013 and 2015.

	Visual Studio 2013	Visual Studio 2015
Eigen 3.2.7	success	failure
Eigen 3.2.8	success	success
Eigen 3.3.0 beta1	failure	success

This issue has been resolved.
Thanks.