Print error message

- fix 2 typos (uint16_t to Walrus::ByteCodeStackOffset)

- fix 1 typo (because of it 3 tests failed, altough it was
  unnoticable hence the error wasn't caught)

- refactor nested if...else to switch...case

- print error message before exit

- make string() operator for Value class

src/parser/WASMParser.cpp

@@ -1703,7 +1703,7 @@ class WASMBinaryReader : public wabt::WASMBinaryReaderDelegate {
             ASSERT(peekVMStackValueType() == Walrus::Value::Type::I32);
             auto stackPos = popVMStack();
             size_t pos = m_currentFunction->currentByteCodeSize();
-            pushByteCode(Walrus::JumpIfFalse(stackPos), WASMOpcode::BrIfOpcode);
+            pushByteCode(Walrus::JumpIfFalse(stackPos, sizeof(Walrus::JumpIfFalse) + sizeof(Walrus::End) + sizeof(Walrus::ByteCodeStackOffset) * m_currentFunctionType->result().size()), WASMOpcode::BrIfOpcode);
             for (size_t i = 0; i < m_currentFunctionType->result().size(); i++) {
                 ASSERT((m_vmStack.rbegin() + i)->valueType() == m_currentFunctionType->result()[m_currentFunctionType->result().size() - i - 1]);
             }
@@ -1848,7 +1848,7 @@ class WASMBinaryReader : public wabt::WASMBinaryReaderDelegate {
         if (tagIndex != std::numeric_limits<Index>::max()) {
             auto functionType = m_result.m_functionTypes[m_result.m_tagTypes[tagIndex]->sigIndex()];
             auto& param = functionType->param();
-            m_currentFunction->expandByteCode(sizeof(uint16_t) * param.size());
+            m_currentFunction->expandByteCode(sizeof(Walrus::ByteCodeStackOffset) * param.size());
             Walrus::Throw* code = m_currentFunction->peekByteCode<Walrus::Throw>(pos);
             for (size_t i = 0; i < param.size(); i++) {
                 code->dataOffsets()[param.size() - i - 1] = (m_vmStack.rbegin() + i)->position();

src/runtime/Value.h

@@ -363,6 +363,26 @@ class Value {
         return false;
     }
 
+    operator std::string() const
+    {
+        switch (m_type) {
+        case I32:
+            return std::to_string(asI32());
+        case I64:
+            return std::to_string(asI64());
+        case F32:
+            return std::to_string(asF32());
+        case F64:
+            return std::to_string(asF64());
+        case FuncRef:
+        case ExternRef:
+            return std::to_string((size_t)(asExternal()));
+        default:
+            ASSERT_NOT_REACHED();
+            return "";
+        }
+    }
+
 private:
     union {
         int32_t m_i32;