Emit vtables once

This fixes -Wweak-vtable warnings

lib/fizzy/CMakeLists.txt

@@ -9,6 +9,8 @@ target_sources(
     fizzy PRIVATE
     bytes.hpp
     constexpr_vector.hpp
+    exceptions.cpp
+    exceptions.hpp
     execute.cpp
     execute.hpp
     instructions.cpp

lib/fizzy/exceptions.cpp

@@ -0,0 +1,12 @@
+// Fizzy: A fast WebAssembly interpreter
+// Copyright 2020 The Fizzy Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "exceptions.hpp"
+
+namespace fizzy
+{
+parser_error::~parser_error() noexcept = default;
+validation_error::~validation_error() noexcept = default;
+instantiate_error::~instantiate_error() noexcept = default;
+}  // namespace fizzy

lib/fizzy/exceptions.hpp

@@ -11,16 +11,22 @@ namespace fizzy
 struct parser_error : public std::runtime_error
 {
     using runtime_error::runtime_error;
+
+    ~parser_error() noexcept override;
 };
 
 struct validation_error : public std::runtime_error
 {
     using runtime_error::runtime_error;
+
+    ~validation_error() noexcept override;
 };
 
 struct instantiate_error : public std::runtime_error
 {
     using runtime_error::runtime_error;
+
+    ~instantiate_error() noexcept override;
 };
 
 }  // namespace fizzy

test/utils/wasm_engine.cpp

@@ -2,11 +2,14 @@
 // Copyright 2020 The Fizzy Authors.
 // SPDX-License-Identifier: Apache-2.0
 
+#include "wasm_engine.hpp"
 #include <stdexcept>
 #include <string>
 
 namespace fizzy::test
 {
+WasmEngine::~WasmEngine() noexcept = default;
+
 void validate_function_signature(std::string_view signature)
 {
     if (signature.find_first_of(":") == std::string::npos)

test/utils/wasm_engine.hpp

@@ -24,7 +24,7 @@ class WasmEngine
         std::optional<uint64_t> value;
     };
 
-    virtual ~WasmEngine() noexcept = default;
+    virtual ~WasmEngine() noexcept;
 
     /// Parses input wasm binary. The created module is discarded.
     /// Returns false on parsing error.