Make it possible to check that an implementation is supported at runtime (#1197)

* Make it possible to check that an implementation is supported at runtime.

* add CI fuzzing on arm 64 bit

This adds fuzzing on drone.io arm64

For some reason, leak detection had to be disabled. If it is enabled, the fuzzer falsely reports a crash at the end of fuzzing.

Closes: #1188

* Guarding the implementation accesses.

* Better doc.

* Updating cxxopts.

* Make it possible to check that an implementation is supported at runtime.

* Guarding the implementation accesses.

* Better doc.

* Updating cxxopts.

* We need to accomodate cxxopts

Co-authored-by: Paul Dreik <github@pauldreik.se>

tests/basictests.cpp

@@ -1868,6 +1868,10 @@ int main(int argc, char *argv[]) {
         fprintf(stderr, "Unsupported architecture value -a %s\n", optarg);
         return EXIT_FAILURE;
       }
+      if(!impl->supported_by_runtime_system()) {
+        fprintf(stderr, "The selected implementation does not match your current CPU: -a %s\n", optarg);
+        return EXIT_FAILURE;
+      }
       simdjson::active_implementation = impl;
       break;
     }

tests/document_stream_tests.cpp

@@ -340,6 +340,10 @@ int main(int argc, char *argv[]) {
         fprintf(stderr, "Unsupported architecture value -a %s\n", optarg);
         return EXIT_FAILURE;
       }
+      if(!impl->supported_by_runtime_system()) {
+        fprintf(stderr, "The selected implementation does not match your current CPU: -a %s\n", optarg);
+        return EXIT_FAILURE;
+      }
       simdjson::active_implementation = impl;
       break;
     }

tests/document_tests.cpp

@@ -202,6 +202,10 @@ int main(int argc, char *argv[]) {
         fprintf(stderr, "Unsupported architecture value -a %s\n", optarg);
         return EXIT_FAILURE;
       }
+      if(!impl->supported_by_runtime_system()) {
+        fprintf(stderr, "The selected implementation does not match your current CPU: -a %s\n", optarg);
+        return EXIT_FAILURE;
+      }
       simdjson::active_implementation = impl;
       break;
     }

tests/jsoncheck.cpp

@@ -119,6 +119,10 @@ int main(int argc, char *argv[]) {
         fprintf(stderr, "Unsupported architecture value -a %s\n", optarg);
         return EXIT_FAILURE;
       }
+      if(!impl->supported_by_runtime_system()) {
+        fprintf(stderr, "The selected implementation does not match your current CPU: -a %s\n", optarg);
+        return EXIT_FAILURE;
+      }
       simdjson::active_implementation = impl;
       break;
     }

tests/minefieldcheck.cpp

@@ -117,6 +117,10 @@ int main(int argc, char *argv[]) {
         fprintf(stderr, "Unsupported architecture value -a %s\n", optarg);
         return EXIT_FAILURE;
       }
+      if(!impl->supported_by_runtime_system()) {
+        fprintf(stderr, "The selected implementation does not match your current CPU: -a %s\n", optarg);
+        return EXIT_FAILURE;
+      }
       simdjson::active_implementation = impl;
       break;
     }

tests/readme_examples.cpp

@@ -201,10 +201,24 @@ void implementation_selection_2() {
   }
 }
 
+void implementation_selection_2_safe() {
+  for (auto implementation : simdjson::available_implementations) {
+    if(implementation->supported_by_runtime_system()) {
+      cout << implementation->name() << ": " << implementation->description() << endl;
+    }
+  }
+}
 void implementation_selection_3() {
   cout << simdjson::available_implementations["fallback"]->description() << endl;
 }
 
+void implementation_selection_safe() {
+  auto my_implementation = simdjson::available_implementations["haswell"];
+  if(! my_implementation) { exit(1); }
+  if(! my_implementation->supported_by_runtime_system()) { exit(1); }
+  simdjson::active_implementation = my_implementation;
+}
+
 void implementation_selection_4() {
   // Use the fallback implementation, even though my machine is fast enough for anything
   simdjson::active_implementation = simdjson::available_implementations["fallback"];