[BUG] shared_ptr of ConstraintContext doesn't compile with clang

[abergeron]

The current master doesn't build on mac because of this:

• shared_ptr on ConstraintContext: https://github.com/dmlc/tvm/blob/master/src/api/api_arith.cc#L112
• destructor of that class is marked as throwing: https://github.com/dmlc/tvm/blob/master/include/tvm/arithmetic.h#L220

I've read that the C++ spec doesn't support destructors that throw for shared_ptr. I don't know if that is true, but clang doesn't like it and fails to compile with this:

[  8%] Building CXX object CMakeFiles/tvm.dir/src/api/api_arith.cc.o
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++  -DDMLC_USE_FOPEN64=0 -DTVM_LLVM_VERSION=60 -Dtvm_EXPORTS -I/Users/anakha/ext/tvm/include -I/Users/anakha/ext/tvm/3rdparty/dlpack/include -I/Users/anakha/ext/tvm/3rdparty/dmlc-core/include -I/Users/anakha/ext/tvm/3rdparty/rang/include -I/Users/anakha/ext/tvm/3rdparty/compiler-rt -F/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks -I/Users/anakha/miniconda/include -I/Users/anakha/ext/tvm/3rdparty/HalideIR/src -I/Users/anakha/ext/tvm/topi/include  -O2 -Wall -fPIC -fvisibility=hidden -std=c++11  -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -mmacosx-version-min=10.11 -fPIC   -D_DEBUG -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -o CMakeFiles/tvm.dir/src/api/api_arith.cc.o -c /Users/anakha/ext/tvm/src/api/api_arith.cc
In file included from /Users/anakha/ext/tvm/src/api/api_arith.cc:6:
In file included from /Users/anakha/ext/tvm/include/tvm/expr.h:9:
In file included from /Users/anakha/ext/tvm/3rdparty/HalideIR/src/ir/Expr.h:7:
In file included from /Users/anakha/ext/tvm/3rdparty/HalideIR/src/tvm/node/node.h:9:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string:477:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string_view:176:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__string:56:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:643:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/memory:3604:7: error: 
      exception specification of overriding function is more lax than base
      version
class __shared_ptr_emplace
      ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/memory:4277:26: note: 
      in instantiation of template class
      'std::__1::__shared_ptr_emplace<tvm::arith::ConstraintContext,
      std::__1::allocator<tvm::arith::ConstraintContext> >' requested here
    ::new(__hold2.get()) _CntrlBlk(__a2, _VSTD::forward<_Args>(__args)...);
                         ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/memory:4656:29: note: 
      in instantiation of function template specialization
      'std::__1::shared_ptr<tvm::arith::ConstraintContext>::make_shared<tvm::arith::Analyzer
      *, tvm::runtime::TVMArgValue>' requested here
    return shared_ptr<_Tp>::make_shared(_VSTD::forward<_Args>(__args)...);
                            ^
/Users/anakha/ext/tvm/src/api/api_arith.cc:112:29: note: in instantiation of
      function template specialization
      'std::__1::make_shared<tvm::arith::ConstraintContext, tvm::arith::Analyzer
      *, tvm::runtime::TVMArgValue>' requested here
            auto ctx = std::make_shared<ConstraintContext>(self.get(), args[0]);
                            ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/memory:3513:13: note: 
      overridden virtual function is here
    virtual ~__shared_weak_count();
            ^
1 error generated.
make[2]: *** [CMakeFiles/tvm.dir/src/api/api_arith.cc.o] Error 1
make[1]: *** [CMakeFiles/tvm.dir/all] Error 2
make: *** [all] Error 2

I'm not familiar enough with that part of the code to know what the proper fix would be.

[abergeron]

By current master I mean eae76b3

[abergeron]

git blame says this PR introduced the failing code: #2668

@tqchen

[tqchen]

fixed by #2731 Thanks for reporting and sorry for the trouble