sycl: fix error building scheduler.cpp

[airlied]

On Fedora 28 with gcc version 8.2.1 20181105 (Red Hat 8.2.1-5) (GCC)
building the SYCL stack gives:
/home/airlied/devel/compute/intel/llvm/sycl/include/CL/sycl/detail/scheduler/scheduler.cpp: In member function ‘void cl::sycl::simple_scheduler::Node::addAccRequirement(cl::sycl::accessor<dataT, dimensions, accessMode, accessTarget, isPlaceholder>&&, int)’:
/home/airlied/devel/compute/intel/llvm/sycl/include/CL/sycl/detail/scheduler/scheduler.cpp:66:48: error: expected ‘,’ or ‘;’ before ‘::’ token
isPlaceholder>::__impl()

Change to ._impl() which seems to compile fine.

[airlied]

Fixes #8

[bader]

I think the right fix is to remove the declaration of the base class. I.e.

detail::buffer_impl<dataT, dimensions> *buf = Acc.__impl()->m_Buf;

Otherwise I see compilation errors from the GCC 5.4 about wrong usage of accessor_base class.
Could you check if proposed change fixes the build with GCC 8, please?

[airlied]

I've pushed a new fix, as suggested, seems to compile fine here.

[Ruyk]

The fix works for me on GCC 7.3, is this only waiting GCC 8.0 testing now?

[bader]

I hope David is working on fixing lit test failures.
@Ruyk, does make check-sycl work for you?

[Ruyk]

They don't, I get the following:

In file included from /home/ruyman/Projects/sycl/sycl/test/basic_tests/handler/handler_mem_op.cpp:13:                 
In file included from /home/ruyman/Projects/sycl/build/lib/clang/9.0.0/include/CL/sycl.hpp:46:                        
/home/ruyman/Projects/sycl/build/lib/clang/9.0.0/include/CL/sycl/detail/scheduler/scheduler.cpp:129:25: error: '__imp$
' is a private member of 'cl::sycl::accessor<int, 1, cl::sycl::access::mode::write, cl::sycl::access::target::global_$
uffer, cl::sycl::access::placeholder::false_t>'                                                                       
  auto *DestBase = Dest.__impl();                                                                                     
                        ^                                                                                             
/home/ruyman/Projects/sycl/build/lib/clang/9.0.0/include/CL/sycl/handler.hpp:705:14: note: in instantiation of functi$
n template specialization 'cl::sycl::simple_scheduler::Node::addExplicitMemOp<int, 1, cl::sycl::access::mode::write, $
l::sycl::access::target::global_buffer, cl::sycl::access::placeholder::false_t>' requested here                       
      m_Node.addExplicitMemOp<>(dest, src);                                                                           
             ^                                                                                                        
/home/ruyman/Projects/sycl/sycl/test/basic_tests/handler/handler_mem_op.cpp:134:11: note: in instantiation of functio$
 template specialization 'cl::sycl::handler::fill<int, 1, cl::sycl::access::mode::write, cl::sycl::access::target::gl$
bal_buffer, cl::sycl::access::placeholder::false_t>' requested here                                                         Cgh.fill(Accessor, Value);                                                                                      
          ^                                                                                                           
/home/ruyman/Projects/sycl/sycl/test/basic_tests/handler/handler_mem_op.cpp:44:5: note: in instantiation of function $
emplate specialization 'test_fill<int>' requested here                                                                    test_fill<int>(888);                                                                                              
    ^                                                                                                                 
/home/ruyman/Projects/sycl/build/lib/clang/9.0.0/include/CL/sycl/accessor.hpp:560:10: note: implicitly declared priva$
e here                                                                                                                
  _ImplT __impl;                                                                                                      
         ^                                                                                                 

and, probably unrelated,

In file included from /home/ruyman/Projects/sycl/sycl/test/sub_group/barrier.cpp:14:   
/home/ruyman/Projects/sycl/sycl/test/sub_group/helper.hpp:105:9: error: call to 'abs' is ambiguous                    
    if (std::abs(val - ref) != 0) {                                                                                   
        ^~~~~~~~                                                                                                      
/home/ruyman/Projects/sycl/sycl/test/sub_group/barrier.cpp:63:7: note: in instantiation of function template specializ
ation 'exit_if_not_equal<unsigned int>' requested here
      exit_if_not_equal<T>(addacc[j], add, "barrier");                                                                
      ^                                                                                                               
/home/ruyman/Projects/sycl/sycl/test/sub_group/barrier.cpp:77:3: note: in instantiation of function template specializ
ation 'check<unsigned int>' requested here                                                                            
  check<unsigned int>(Queue);                                                                                         
  ^                                                                                                                   
/usr/include/stdlib.h:837:12: note: candidate function                                                                
extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur;                                                   
           ^                                                                                                          
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:56:3: note: candidate function               
  abs(long __i) { return __builtin_labs(__i); }                                                                       
  ^                                                                                                                   
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:61:3: note: candidate function               
  abs(long long __x) { return __builtin_llabs (__x); }                                                               
  ^                                                                                                                   
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:70:3: note: candidate function               
  abs(double __x)                                                                                                     
  ^                                                                                                                   
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:74:3: note: candidate function               
  abs(float __x)                                                                                                      
  ^                                                                                                                   
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:78:3: note: candidate function               
  abs(long double __x)
  ^
In file included from /home/ruyman/Projects/sycl/sycl/test/sub_group/barrier.cpp:14:
/home/ruyman/Projects/sycl/sycl/test/sub_group/helper.hpp:105:9: error: call to 'abs' is ambiguous
    if (std::abs(val - ref) != 0) {
        ^~~~~~~~
/home/ruyman/Projects/sycl/sycl/test/sub_group/barrier.cpp:63:7: note: in instantiation of function template specializ
ation 'exit_if_not_equal<unsigned long>' requested here
      exit_if_not_equal<T>(addacc[j], add, "barrier");
      ^
/home/ruyman/Projects/sycl/sycl/test/sub_group/barrier.cpp:79:3: note: in instantiation of function template specializ
ation 'check<unsigned long>' requested here
  check<unsigned long>(Queue);
  ^
/usr/include/stdlib.h:837:12: note: candidate function
extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur;
           ^
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:56:3: note: candidate function
  abs(long __i) { return __builtin_labs(__i); }
  ^
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:61:3: note: candidate function
  abs(long long __x) { return __builtin_llabs (__x); }
  ^
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:70:3: note: candidate function
  abs(double __x)
  ^
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:74:3: note: candidate function
  abs(float __x)
  ^
/usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/std_abs.h:78:3: note: candidate function
  abs(long double __x)
  ^
2 errors generated.

[keryell]

@Ruyk said:

and, probably unrelated,

In file included from /home/ruyman/Projects/sycl/sycl/test/sub_group/barrier.cpp:14:   
/home/ruyman/Projects/sycl/sycl/test/sub_group/helper.hpp:105:9: error: call to 'abs' is ambiguous                    
    if (std::abs(val - ref) != 0) {                                                                                   
        ^~~~~~~~                                                                                                      
/home/ruyman/Projects/sycl/sycl/test/sub_group/barrier.cpp:63:7: note: in instantiation of function template specializ
ation 'exit_if_not_equal<unsigned int>' requested here
      exit_if_not_equal<T>(addacc[j], add, "barrier");                                                                
      ^                                                                                                               

Yes, I noticed that yesterday.
I created #29 on these failures.

[airlied]

This is because we are trying to access a base class method via friend relationship in the subclass, and you don't inherit friend

I'm digging around to see what might be the nicest answer to this, either adding more friend (a fair bit of cut-n-paste) or if accessing the base class method is possible.

[airlied]

I've pushed a more hacky version to see if this one passes CI at all, I'm not sure it's what we'd want to merge but it more clearly demonstrates the friend problem, but unfortunately suffers from a namespace collision that I've worked around badly.

[bader]

We definitely should re-design this part.
@romanovvlad, any suggestions for fixing this issue?

[bader]

I've pushed a more hacky version to see if this one passes CI at all, I'm not sure it's what we'd want to merge but it more clearly demonstrates the friend problem, but unfortunately suffers from a namespace collision that I've worked around badly.

I created PR #36 with a little bit invasive changes to the compiler.
@airlied, could you try it out, please?

[bader]

Scheduler build issues are resolved by #36.
Closing this PR.