Merge pull request #632 from ethereum/helpers_cxx

helpers: Improve compatibility with C++

CMakeLists.txt

@@ -56,7 +56,10 @@ endif()
 cable_configure_compiler(NO_STACK_PROTECTION)
 if(CABLE_COMPILER_GNULIKE)
     # TODO: Resolve issues or remove "result optional storage" and enable -Wcast-align.
-    add_compile_options(-Wmissing-declarations)
+    add_compile_options(
+        -Wmissing-declarations
+        $<$<COMPILE_LANGUAGE:CXX>:-Wold-style-cast>
+    )
     cable_add_cxx_compiler_flag_if_supported(-Wfinal-dtor-non-final-class)
     cable_add_cxx_compiler_flag_if_supported(-Wnewline-eof)
     cable_add_cxx_compiler_flag_if_supported(-Wsuggest-destructor-override)

examples/example_vm/example_vm.cpp

@@ -64,7 +64,7 @@ enum evmc_set_option_result set_option(evmc_vm* instance, const char* name, cons
             return EVMC_SET_OPTION_INVALID_VALUE;
         if (v > 9 || v < -1)  // Not in the valid range.
             return EVMC_SET_OPTION_INVALID_VALUE;
-        vm->verbose = (int)v;
+        vm->verbose = static_cast<int>(v);
         return EVMC_SET_OPTION_SUCCESS;
     }
 

include/evmc/helpers.h

@@ -9,8 +9,6 @@
  * These are convenient for languages where invoking function pointers
  * is "ugly" or impossible (such as Go).
  *
- * It also contains helpers (overloaded operators) for using EVMC types effectively in C++.
- *
  * @defgroup helpers EVMC Helpers
  * @{
  */
@@ -20,6 +18,12 @@
 #include <stdlib.h>
 #include <string.h>
 
+#ifdef __cplusplus
+extern "C" {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wold-style-cast"
+#endif
+
 /**
  * Returns true if the VM has a compatible ABI version.
  */
@@ -293,3 +297,8 @@ static inline const char* evmc_revision_to_string(enum evmc_revision rev)
 }
 
 /** @} */
+
+#ifdef __cplusplus
+#pragma GCC diagnostic pop
+}  // extern "C"
+#endif