Reduce the extent of unsafe code.

lib/wasmstandalone/src/execution.rs

@@ -124,12 +124,13 @@ pub fn compile_module(
 /// Jumps to the code region of memory and execute the start function of the module.
 pub fn execute(exec: &ExecutableCode) -> Result<(), String> {
     let code_buf = &exec.functions_code[exec.start_index];
-    unsafe {
+    match unsafe {
-        match protect(
+        protect(
             code_buf.as_ptr(),
             code_buf.len(),
             Protection::ReadWriteExecute,
-        ) {
+        )
+    } {
         Ok(()) => (),
         Err(err) => {
             return Err(format!(
@@ -137,15 +138,16 @@ pub fn execute(exec: &ExecutableCode) -> Result<(), String> {
                 err.description()
             ))
         }
-        };
+    }
     // Rather than writing inline assembly to jump to the code region, we use the fact that
     // the Rust ABI for calling a function with no arguments and no return matches the one of
     // the generated code.Thanks to this, we can transmute the code region into a first-class
     // Rust function and call it.
+    unsafe {
         let start_func = transmute::<_, fn()>(code_buf.as_ptr());
         start_func();
-        Ok(())
     }
+    Ok(())
 }
 
 /// Performs the relocations inside the function bytecode, provided the necessary metadata