[flang] Implement CFI_show()

Implement in runtime and add declaration to ISO_Fortran_binding.h

Author: eugeneepshteyn

flang-rt/lib/runtime/ISO_Fortran_binding.cpp

@@ -297,6 +297,14 @@ RT_API_ATTRS int CFI_setpointer(CFI_cdesc_t *result, const CFI_cdesc_t *source,
   return CFI_SUCCESS;
 }
 
+RT_API_ATTRS void CFI_show(void *buf, const CFI_cdesc_t *descr) {
+  FILE *f{stderr};
+  std::fprintf(f, "%p CFI_desc_t: %p\n", buf, descr);
+  if (descr) {
+    reinterpret_cast<const Fortran::runtime::Descriptor *>(descr)->Dump(f);
+  }
+}
+
 RT_EXT_API_GROUP_END
 } // extern "C"
 } // namespace Fortran::ISO

flang/include/flang/ISO_Fortran_binding.h

@@ -208,6 +208,7 @@ RT_API_ATTRS int CFI_select_part(CFI_cdesc_t *, const CFI_cdesc_t *source,
     size_t displacement, size_t elem_len);
 RT_API_ATTRS int CFI_setpointer(
     CFI_cdesc_t *, const CFI_cdesc_t *source, const CFI_index_t lower_bounds[]);
+RT_API_ATTRS void CFI_show(void *buf, const CFI_cdesc_t *descr);
 #ifdef __cplusplus
 } // extern "C"
 #endif