[Openmp-commits] [openmp] 6e9cd3e - [libomptarget][nfc] Improve static assert message in dlwrap

[Jon Chesterfield via Openmp-commits]

Author: Jon Chesterfield
Date: 2021-07-22T15:24:20+01:00
New Revision: 6e9cd3e9f1da3880ab8a10d327663449c5d4c65c

URL: https://github.com/llvm/llvm-project/commit/6e9cd3e9f1da3880ab8a10d327663449c5d4c65c
DIFF: https://github.com/llvm/llvm-project/commit/6e9cd3e9f1da3880ab8a10d327663449c5d4c65c.diff

LOG: [libomptarget][nfc] Improve static assert message in dlwrap

Revision of D102858. Raise dlwrap arity argument to template argument
so the correct value is given in the error message. E.g. '2 == 1' instead of
'2 == trait<>::nargs'.

Arity higher than it should be:
Before diff
```
$/plugins/cuda/dynamic_cuda/cuda.cpp:23:1: error:
      static_assert failed due to requirement '2 == trait<cudaError_enum (*)(unsigned int)>::nargs'
      "Arity Error"
DLWRAP_INTERNAL(cuInit, 2);
^~~~~~~~~~~~~~~~~~~~~~~~~~
...
$/include/dlwrap.h:166:3: note: expanded from macro
      'DLWRAP_COMMON'
  static_assert(ARITY == trait<decltype(&SYMBOL)>::nargs, "Arity Error");      \
```

After diff
In file included from $/plugins/cuda/dynamic_cuda/cuda.cpp:16:
```
$/include/dlwrap.h:131:3: error: static_assert failed due to
      requirement '2UL == 1UL' "Arity Error"
  static_assert(Requested == Required, "Arity Error");
  ^             ~~~~~~~~~~~~~~~~~~~~~
$/plugins/cuda/dynamic_cuda/cuda.cpp:23:1: note: in
      instantiation of function template specialization 'dlwrap::verboseAssert<2UL, 1UL>' requested
      here
DLWRAP_INTERNAL(cuInit, 2);
```

Arity lower than it should be:
Before diff
```
$/plugins/cuda/dynamic_cuda/cuda.cpp:131:10: error: no
      matching function for call to 'dlwrap_cuInit'
  return dlwrap_cuInit(X);
         ^~~~~~~~~~~~~
$/plugins/cuda/dynamic_cuda/cuda.cpp:23:1: note: candidate
      function not viable: requires 0 arguments, but 1 was provided
DLWRAP_INTERNAL(cuInit, 0);
```

After diff
In file included from $/plugins/cuda/dynamic_cuda/cuda.cpp:16:
```
$/include/dlwrap.h:131:3: error: static_assert failed due to
      requirement '0UL == 1UL' "Arity Error"
  static_assert(Requested == Required, "Arity Error");
  ^             ~~~~~~~~~~~~~~~~~~~~~
$/plugins/cuda/dynamic_cuda/cuda.cpp:23:1: note: in
      instantiation of function template specialization 'dlwrap::verboseAssert<0UL, 1UL>' requested
      here
DLWRAP_INTERNAL(cuInit, 0);
```

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D106543

Added: 
    

Modified: 
    openmp/libomptarget/include/dlwrap.h

Removed: 
    


################################################################################
diff  --git a/openmp/libomptarget/include/dlwrap.h b/openmp/libomptarget/include/dlwrap.h
index 5ba453a6c3fed..4c9b9352d633d 100644
--- a/openmp/libomptarget/include/dlwrap.h
+++ b/openmp/libomptarget/include/dlwrap.h
@@ -127,6 +127,10 @@ constexpr std::array<const char *, N> static getSymbolArray(
   return {{dlwrap::type::symbol<Is>::call()...}};
 }
 
+template <size_t Requested, size_t Required> constexpr void verboseAssert() {
+  static_assert(Requested == Required, "Arity Error");
+}
+
 } // namespace dlwrap
 
 #define DLWRAP_INSTANTIATE(SYM_USE, SYM_DEF, ARITY)                            \
@@ -153,12 +157,12 @@ constexpr std::array<const char *, N> static getSymbolArray(
   struct SYMBOL##_Trait : public dlwrap::trait<decltype(&SYMBOL)> {            \
     using T = dlwrap::trait<decltype(&SYMBOL)>;                                \
     static T::FunctionType get() {                                             \
+      verboseAssert<ARITY, trait<decltype(&SYMBOL)>::nargs>();                 \
       constexpr size_t Index = DLWRAP_ID() - 1;                                \
       void *P = *dlwrap::pointer(Index);                                       \
       return reinterpret_cast<T::FunctionType>(P);                             \
     }                                                                          \
   };                                                                           \
-  static_assert(ARITY == trait<decltype(&SYMBOL)>::nargs, "Arity Error");      \
   }
 
 #define DLWRAP_IMPL(SYMBOL, ARITY)                                             \