diff --git a/src/binding.cc b/src/binding.cc
index baa8f40c..c1d3e40f 100644
--- a/src/binding.cc
+++ b/src/binding.cc
@@ -22,6 +22,11 @@
 
 using namespace support;
 
+template<typename T>
+constexpr size_t align_to(size_t size) {
+    return (size + sizeof(T) - 1) & ~(sizeof(T) - 1);
+}
+
 static_assert(sizeof(two_pointers_t) ==
                   sizeof(std::shared_ptr<v8::BackingStore>),
               "std::shared_ptr<v8::BackingStore> size mismatch");
@@ -40,7 +45,7 @@ static_assert(sizeof(v8::PromiseRejectMessage) == sizeof(size_t) * 3,
 
 static_assert(sizeof(v8::Locker) == sizeof(size_t) * 2, "Locker size mismatch");
 
-static_assert(sizeof(v8::ScriptCompiler::Source) <= sizeof(size_t) * 8,
+static_assert(sizeof(v8::ScriptCompiler::Source) == align_to<size_t>(sizeof(size_t) * 6 + sizeof(int) * 3),
               "Source size mismatch");
 
 static_assert(sizeof(v8::FunctionCallbackInfo<v8::Value>) == sizeof(size_t) * 3,
diff --git a/src/script_compiler.rs b/src/script_compiler.rs
index 6419f349..af39a06b 100644
--- a/src/script_compiler.rs
+++ b/src/script_compiler.rs
@@ -1,4 +1,5 @@
 // Copyright 2019-2021 the Deno authors. All rights reserved. MIT license.
+use std::os::raw::c_int;
 use std::{marker::PhantomData, mem::MaybeUninit};
 
 use crate::Function;
@@ -61,7 +62,17 @@ extern "C" {
 /// Source code which can then be compiled to a UnboundScript or Script.
 #[repr(C)]
 #[derive(Debug)]
-pub struct Source([usize; 8]);
+pub struct Source {
+  _source_string: usize,
+  _resource_name: usize,
+  _resource_line_offset: c_int,
+  _resource_column_offset: c_int,
+  _resource_options: c_int,
+  _source_map_url: usize,
+  _host_defined_options: usize,
+  _cached_data: usize,
+  _consume_cache_task: usize,
+}
 
 /// Compilation data that the embedder can cache and pass back to speed up future
 /// compilations. The data is produced if the CompilerOptions passed to the compilation