feat(ext/ffi): Safe number pointers (#15173)

3 files changed, 602 insertions, 411 deletions

diff --git a/ext/ffi/00_ffi.js b/ext/ffi/00_ffi.js
index ac8dda317..bc03dfb14 100644
--- a/ext/ffi/00_ffi.js
+++ b/ext/ffi/00_ffi.js
@@ -12,11 +12,19 @@
     TypeError,
   } = window.__bootstrap.primordials;
 
-  function unpackU64([hi, lo]) {
+  function unpackU64(returnValue) {
+    if (typeof returnValue === "number") {
+      return returnValue;
+    }
+    const [hi, lo] = returnValue;
     return BigInt(hi) << 32n | BigInt(lo);
   }
 
-  function unpackI64([hi, lo]) {
+  function unpackI64(returnValue) {
+    if (typeof returnValue === "number") {
+      return returnValue;
+    }
+    const [hi, lo] = returnValue;
     const u64 = unpackU64([hi, lo]);
     return u64 >> 63n ? u64 - 0x10000000000000000n : u64;
   }
@@ -31,77 +39,77 @@
     getUint8(offset = 0) {
       return core.opSync(
         "op_ffi_read_u8",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getInt8(offset = 0) {
       return core.opSync(
         "op_ffi_read_i8",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getUint16(offset = 0) {
       return core.opSync(
         "op_ffi_read_u16",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getInt16(offset = 0) {
       return core.opSync(
         "op_ffi_read_i16",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getUint32(offset = 0) {
       return core.opSync(
         "op_ffi_read_u32",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getInt32(offset = 0) {
       return core.opSync(
         "op_ffi_read_i32",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getBigUint64(offset = 0) {
       return core.opSync(
         "op_ffi_read_u64",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getBigInt64(offset = 0) {
       return core.opSync(
-        "op_ffi_read_u64",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        "op_ffi_read_i64",
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getFloat32(offset = 0) {
       return core.opSync(
         "op_ffi_read_f32",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getFloat64(offset = 0) {
       return core.opSync(
         "op_ffi_read_f64",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
     getCString(offset = 0) {
       return core.opSync(
         "op_ffi_cstr_read",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
       );
     }
 
@@ -116,7 +124,7 @@
     copyInto(destination, offset = 0) {
       core.opSync(
         "op_ffi_buf_copy_into",
-        offset ? this.pointer + BigInt(offset) : this.pointer,
+        offset ? BigInt(this.pointer) + BigInt(offset) : this.pointer,
         destination,
         destination.byteLength,
       );
diff --git a/ext/ffi/jit_trampoline.rs b/ext/ffi/jit_trampoline.rs
index 2fd078d60..12c9b2a7d 100644
--- a/ext/ffi/jit_trampoline.rs
+++ b/ext/ffi/jit_trampoline.rs
@@ -5,6 +5,9 @@ use crate::{tcc::Compiler, Symbol};
 use std::ffi::c_void;
 use std::ffi::CString;
 use std::fmt::Write as _;
+use std::mem::size_of;
+
+const _: () = assert!(size_of::<fn()>() == size_of::<usize>());
 
 pub(crate) struct Allocation {
   pub addr: *mut c_void,
@@ -22,12 +25,14 @@ fn native_arg_to_c(ty: &NativeType) -> &'static str {
   match ty {
     NativeType::U8 | NativeType::U16 | NativeType::U32 => "uint32_t",
     NativeType::I8 | NativeType::I16 | NativeType::I32 => "int32_t",
-    NativeType::U64 | NativeType::USize => "uint64_t",
-    NativeType::I64 | NativeType::ISize => "int64_t",
     NativeType::Void => "void",
     NativeType::F32 => "float",
     NativeType::F64 => "double",
-    _ => unimplemented!(),
+    NativeType::U64 => "uint64_t",
+    NativeType::I64 => "int64_t",
+    NativeType::ISize => "intptr_t",
+    NativeType::USize => "uintptr_t",
+    NativeType::Pointer | NativeType::Function => "void*",
   }
 }
 
@@ -42,9 +47,11 @@ fn native_to_c(ty: &NativeType) -> &'static str {
     NativeType::Void => "void",
     NativeType::F32 => "float",
     NativeType::F64 => "double",
-    NativeType::U64 | NativeType::USize => "uint64_t",
-    NativeType::I64 | NativeType::ISize => "int64_t",
-    _ => unimplemented!(),
+    NativeType::U64 => "uint64_t",
+    NativeType::I64 => "int64_t",
+    NativeType::ISize => "intptr_t",
+    NativeType::USize => "uintptr_t",
+    NativeType::Pointer | NativeType::Function => "void*",
   }
 }
 
@@ -180,16 +187,16 @@ mod tests {
     assert_eq!(
       codegen(vec![NativeType::ISize, NativeType::U64], NativeType::Void),
       "#include <stdint.h>\n\n\
-      extern void func(int64_t p0, uint64_t p1);\n\n\
-      void func_trampoline(void* recv, int64_t p0, uint64_t p1) {\
+      extern void func(intptr_t p0, uint64_t p1);\n\n\
+      void func_trampoline(void* recv, intptr_t p0, uint64_t p1) {\
         \n  return func(p0, p1);\n\
       }\n\n"
     );
     assert_eq!(
       codegen(vec![NativeType::USize, NativeType::USize], NativeType::U32),
       "#include <stdint.h>\n\n\
-      extern uint32_t func(uint64_t p0, uint64_t p1);\n\n\
-      uint32_t func_trampoline(void* recv, uint64_t p0, uint64_t p1) {\
+      extern uint32_t func(uintptr_t p0, uintptr_t p1);\n\n\
+      uint32_t func_trampoline(void* recv, uintptr_t p0, uintptr_t p1) {\
         \n  return func(p0, p1);\n\
       }\n\n"
     );
diff --git a/ext/ffi/lib.rs b/ext/ffi/lib.rs
index 396affdb3..6d0315964 100644
--- a/ext/ffi/lib.rs
+++ b/ext/ffi/lib.rs
@@ -48,6 +48,9 @@ thread_local! {
   static LOCAL_ISOLATE_POINTER: RefCell<*const v8::Isolate> = RefCell::new(ptr::null());
 }
 
+const MAX_SAFE_INTEGER: isize = 9007199254740991;
+const MIN_SAFE_INTEGER: isize = -9007199254740991;
+
 pub struct Unstable(pub bool);
 
 fn check_unstable(state: &OpState, api_name: &str) {
@@ -93,7 +96,7 @@ struct PtrSymbol {
 }
 
 impl PtrSymbol {
-  fn new(fn_ptr: u64, def: &ForeignFunction) -> Self {
+  fn new(fn_ptr: usize, def: &ForeignFunction) -> Self {
     let ptr = libffi::middle::CodePtr::from_ptr(fn_ptr as _);
     let cif = libffi::middle::Cif::new(
       def
@@ -175,6 +178,7 @@ pub fn init<P: FfiPermissions + 'static>(unstable: bool) -> Extension {
       op_ffi_read_u32::decl::<P>(),
       op_ffi_read_i32::decl::<P>(),
       op_ffi_read_u64::decl::<P>(),
+      op_ffi_read_i64::decl::<P>(),
       op_ffi_read_f32::decl::<P>(),
       op_ffi_read_f64::decl::<P>(),
       op_ffi_unsafe_callback_create::decl::<P>(),
@@ -323,21 +327,46 @@ impl NativeValue {
       NativeType::U32 => Value::from(self.u32_value),
       NativeType::I32 => Value::from(self.i32_value),
       NativeType::U64 => {
-        json!(U32x2::from(self.u64_value))
+        let value = self.u64_value;
+        if value > MAX_SAFE_INTEGER as u64 {
+          json!(U32x2::from(self.u64_value))
+        } else {
+          Value::from(value)
+        }
       }
       NativeType::I64 => {
-        json!(U32x2::from(self.i64_value as u64))
+        let value = self.i64_value;
+        if value > MAX_SAFE_INTEGER as i64 || value < MIN_SAFE_INTEGER as i64 {
+          json!(U32x2::from(self.i64_value as u64))
+        } else {
+          Value::from(value)
+        }
       }
       NativeType::USize => {
-        json!(U32x2::from(self.usize_value as u64))
+        let value = self.usize_value;
+        if value > MAX_SAFE_INTEGER as usize {
+          json!(U32x2::from(self.usize_value as u64))
+        } else {
+          Value::from(value)
+        }
       }
       NativeType::ISize => {
-        json!(U32x2::from(self.isize_value as u64))
+        let value = self.isize_value;
+        if value > MAX_SAFE_INTEGER || value < MIN_SAFE_INTEGER {
+          json!(U32x2::from(self.isize_value as u64))
+        } else {
+          Value::from(value)
+        }
       }
       NativeType::F32 => Value::from(self.f32_value),
       NativeType::F64 => Value::from(self.f64_value),
       NativeType::Pointer | NativeType::Function => {
-        json!(U32x2::from(self.pointer as u64))
+        let value = self.pointer as usize;
+        if value > MAX_SAFE_INTEGER as usize {
+          json!(U32x2::from(value as u64))
+        } else {
+          Value::from(value)
+        }
       }
     }
   }
@@ -385,23 +414,44 @@ impl NativeValue {
         local_value.into()
       }
       NativeType::U64 => {
+        let value = self.u64_value;
         let local_value: v8::Local<v8::Value> =
-          v8::BigInt::new_from_u64(scope, self.u64_value).into();
+          if value > MAX_SAFE_INTEGER as u64 {
+            v8::BigInt::new_from_u64(scope, value).into()
+          } else {
+            v8::Number::new(scope, value as f64).into()
+          };
         local_value.into()
       }
       NativeType::I64 => {
+        let value = self.i64_value;
         let local_value: v8::Local<v8::Value> =
-          v8::BigInt::new_from_i64(scope, self.i64_value).into();
+          if value > MAX_SAFE_INTEGER as i64 || value < MIN_SAFE_INTEGER as i64
+          {
+            v8::BigInt::new_from_i64(scope, self.i64_value).into()
+          } else {
+            v8::Number::new(scope, value as f64).into()
+          };
         local_value.into()
       }
       NativeType::USize => {
+        let value = self.usize_value;
         let local_value: v8::Local<v8::Value> =
-          v8::BigInt::new_from_u64(scope, self.usize_value as u64).into();
+          if value > MAX_SAFE_INTEGER as usize {
+            v8::BigInt::new_from_u64(scope, value as u64).into()
+          } else {
+            v8::Number::new(scope, value as f64).into()
+          };
         local_value.into()
       }
       NativeType::ISize => {
+        let value = self.isize_value;
         let local_value: v8::Local<v8::Value> =
-          v8::BigInt::new_from_i64(scope, self.isize_value as i64).into();
+          if value > MAX_SAFE_INTEGER || value < MIN_SAFE_INTEGER {
+            v8::BigInt::new_from_i64(scope, self.isize_value as i64).into()
+          } else {
+            v8::Number::new(scope, value as f64).into()
+          };
         local_value.into()
       }
       NativeType::F32 => {
@@ -415,8 +465,13 @@ impl NativeValue {
         local_value.into()
       }
       NativeType::Pointer | NativeType::Function => {
+        let value = self.pointer as u64;
         let local_value: v8::Local<v8::Value> =
-          v8::BigInt::new_from_u64(scope, self.pointer as u64).into();
+          if value > MAX_SAFE_INTEGER as u64 {
+            v8::BigInt::new_from_u64(scope, value).into()
+          } else {
+            v8::Number::new(scope, value as f64).into()
+          };
         local_value.into()
       }
     }
@@ -677,10 +732,11 @@ impl From<&NativeType> for fast_api::Type {
       NativeType::F32 => fast_api::Type::Float32,
       NativeType::F64 => fast_api::Type::Float64,
       NativeType::Void => fast_api::Type::Void,
-      NativeType::I64 | NativeType::ISize => fast_api::Type::Int64,
-      NativeType::U64 | NativeType::USize => fast_api::Type::Uint64,
-      NativeType::Function | NativeType::Pointer => {
-        panic!("Cannot be fast api")
+      NativeType::I64 => fast_api::Type::Int64,
+      NativeType::U64 => fast_api::Type::Uint64,
+      NativeType::ISize => fast_api::Type::Int64,
+      NativeType::USize | NativeType::Function | NativeType::Pointer => {
+        fast_api::Type::Uint64
       }
     }
   }
@@ -699,11 +755,6 @@ fn is_fast_api_rv(rv: NativeType) -> bool {
   )
 }
 
-#[cfg(not(target_os = "windows"))]
-fn is_fast_api_arg(rv: NativeType) -> bool {
-  !matches!(rv, NativeType::Function | NativeType::Pointer)
-}
-
 // Create a JavaScript function for synchronous FFI call to
 // the given symbol.
 fn make_sync_fn<'s>(
@@ -719,10 +770,7 @@ fn make_sync_fn<'s>(
   #[cfg(not(target_os = "windows"))]
   let mut fast_allocations: Option<*mut ()> = None;
   #[cfg(not(target_os = "windows"))]
-  if !sym.can_callback
-    && !sym.parameter_types.iter().any(|t| !is_fast_api_arg(*t))
-    && is_fast_api_rv(sym.result_type)
-  {
+  if !sym.can_callback && is_fast_api_rv(sym.result_type) {
     let ret = fast_api::Type::from(&sym.result_type);
 
     let mut args = sym
@@ -792,6 +840,228 @@ fn make_sync_fn<'s>(
   weak.to_local(scope).unwrap()
 }
 
+#[inline]
+fn ffi_parse_u8_arg(
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  let u8_value = v8::Local::<v8::Uint32>::try_from(arg)
+    .map_err(|_| type_error("Invalid FFI u8 type, expected unsigned integer"))?
+    .value() as u8;
+  Ok(NativeValue { u8_value })
+}
+
+#[inline]
+fn ffi_parse_i8_arg(
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  let i8_value = v8::Local::<v8::Int32>::try_from(arg)
+    .map_err(|_| type_error("Invalid FFI i8 type, expected integer"))?
+    .value() as i8;
+  Ok(NativeValue { i8_value })
+}
+
+#[inline]
+fn ffi_parse_u16_arg(
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  let u16_value = v8::Local::<v8::Uint32>::try_from(arg)
+    .map_err(|_| type_error("Invalid FFI u16 type, expected unsigned integer"))?
+    .value() as u16;
+  Ok(NativeValue { u16_value })
+}
+
+#[inline]
+fn ffi_parse_i16_arg(
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  let i16_value = v8::Local::<v8::Int32>::try_from(arg)
+    .map_err(|_| type_error("Invalid FFI i16 type, expected integer"))?
+    .value() as i16;
+  Ok(NativeValue { i16_value })
+}
+
+#[inline]
+fn ffi_parse_u32_arg(
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  let u32_value = v8::Local::<v8::Uint32>::try_from(arg)
+    .map_err(|_| type_error("Invalid FFI u32 type, expected unsigned integer"))?
+    .value() as u32;
+  Ok(NativeValue { u32_value })
+}
+
+#[inline]
+fn ffi_parse_i32_arg(
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  let i32_value = v8::Local::<v8::Int32>::try_from(arg)
+    .map_err(|_| type_error("Invalid FFI i32 type, expected integer"))?
+    .value() as i32;
+  Ok(NativeValue { i32_value })
+}
+
+#[inline]
+fn ffi_parse_u64_arg(
+  scope: &mut v8::HandleScope,
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  // Order of checking:
+  // 1. BigInt: Uncommon and not supported by Fast API, so optimise slow call for this case.
+  // 2. Number: Common, supported by Fast API, so let that be the optimal case.
+  let u64_value: u64 = if let Ok(value) = v8::Local::<v8::BigInt>::try_from(arg)
+  {
+    value.u64_value().0
+  } else if let Ok(value) = v8::Local::<v8::Number>::try_from(arg) {
+    value.integer_value(scope).unwrap() as u64
+  } else {
+    return Err(type_error(
+      "Invalid FFI u64 type, expected unsigned integer",
+    ));
+  };
+  Ok(NativeValue { u64_value })
+}
+
+#[inline]
+fn ffi_parse_i64_arg(
+  scope: &mut v8::HandleScope,
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  // Order of checking:
+  // 1. BigInt: Uncommon and not supported by Fast API, so optimise slow call for this case.
+  // 2. Number: Common, supported by Fast API, so let that be the optimal case.
+  let i64_value: i64 = if let Ok(value) = v8::Local::<v8::BigInt>::try_from(arg)
+  {
+    value.i64_value().0
+  } else if let Ok(value) = v8::Local::<v8::Number>::try_from(arg) {
+    value.integer_value(scope).unwrap() as i64
+  } else {
+    return Err(type_error("Invalid FFI i64 type, expected integer"));
+  };
+  Ok(NativeValue { i64_value })
+}
+
+#[inline]
+fn ffi_parse_usize_arg(
+  scope: &mut v8::HandleScope,
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  // Order of checking:
+  // 1. BigInt: Uncommon and not supported by Fast API, so optimise slow call for this case.
+  // 2. Number: Common, supported by Fast API, so let that be the optimal case.
+  let usize_value: usize =
+    if let Ok(value) = v8::Local::<v8::BigInt>::try_from(arg) {
+      value.u64_value().0 as usize
+    } else if let Ok(value) = v8::Local::<v8::Number>::try_from(arg) {
+      value.integer_value(scope).unwrap() as usize
+    } else {
+      return Err(type_error("Invalid FFI usize type, expected integer"));
+    };
+  Ok(NativeValue { usize_value })
+}
+
+#[inline]
+fn ffi_parse_isize_arg(
+  scope: &mut v8::HandleScope,
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  // Order of checking:
+  // 1. BigInt: Uncommon and not supported by Fast API, so optimise slow call for this case.
+  // 2. Number: Common, supported by Fast API, so let that be the optimal case.
+  let isize_value: isize =
+    if let Ok(value) = v8::Local::<v8::BigInt>::try_from(arg) {
+      value.i64_value().0 as isize
+    } else if let Ok(value) = v8::Local::<v8::Number>::try_from(arg) {
+      value.integer_value(scope).unwrap() as isize
+    } else {
+      return Err(type_error("Invalid FFI isize type, expected integer"));
+    };
+  Ok(NativeValue { isize_value })
+}
+
+#[inline]
+fn ffi_parse_f32_arg(
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  let f32_value = v8::Local::<v8::Number>::try_from(arg)
+    .map_err(|_| type_error("Invalid FFI f32 type, expected number"))?
+    .value() as f32;
+  Ok(NativeValue { f32_value })
+}
+
+#[inline]
+fn ffi_parse_f64_arg(
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  let f64_value = v8::Local::<v8::Number>::try_from(arg)
+    .map_err(|_| type_error("Invalid FFI f64 type, expected number"))?
+    .value() as f64;
+  Ok(NativeValue { f64_value })
+}
+
+#[inline]
+fn ffi_parse_pointer_arg(
+  scope: &mut v8::HandleScope,
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  // Order of checking:
+  // 1. ArrayBufferView: Common and not supported by Fast API, optimise this case.
+  // 2. BigInt: Uncommon and not supported by Fast API, optimise this case as second.
+  // 3. Number: Common and supported by Fast API, optimise the common case third.
+  // 4. ArrayBuffer: Fairly common and not supported by Fast API.
+  // 5. Null: Very uncommon / can be represented by a 0.
+  let pointer = if let Ok(value) =
+    v8::Local::<v8::ArrayBufferView>::try_from(arg)
+  {
+    let byte_offset = value.byte_offset();
+    let backing_store = value
+      .buffer(scope)
+      .ok_or_else(|| {
+        type_error("Invalid FFI ArrayBufferView, expected data in the buffer")
+      })?
+      .get_backing_store();
+    if byte_offset > 0 {
+      &backing_store[byte_offset..] as *const _ as *const u8
+    } else {
+      &backing_store[..] as *const _ as *const u8
+    }
+  } else if let Ok(value) = v8::Local::<v8::BigInt>::try_from(arg) {
+    value.u64_value().0 as usize as *const u8
+  } else if let Ok(value) = v8::Local::<v8::Number>::try_from(arg) {
+    value.integer_value(scope).unwrap() as usize as *const u8
+  } else if let Ok(value) = v8::Local::<v8::ArrayBuffer>::try_from(arg) {
+    let backing_store = value.get_backing_store();
+    &backing_store[..] as *const _ as *const u8
+  } else if arg.is_null() {
+    ptr::null()
+  } else {
+    return Err(type_error("Invalid FFI pointer type, expected null, integer, BigInt, ArrayBuffer, or ArrayBufferView"));
+  };
+  Ok(NativeValue { pointer })
+}
+
+#[inline]
+fn ffi_parse_function_arg(
+  scope: &mut v8::HandleScope,
+  arg: v8::Local<v8::Value>,
+) -> Result<NativeValue, AnyError> {
+  // Order of checking:
+  // 1. BigInt: Uncommon and not supported by Fast API, optimise this case.
+  // 2. Number: Common and supported by Fast API, optimise this case as second.
+  // 3. Null: Very uncommon / can be represented by a 0.
+  let pointer = if let Ok(value) = v8::Local::<v8::BigInt>::try_from(arg) {
+    value.u64_value().0 as usize as *const u8
+  } else if let Ok(value) = v8::Local::<v8::Number>::try_from(arg) {
+    value.integer_value(scope).unwrap() as usize as *const u8
+  } else if arg.is_null() {
+    ptr::null()
+  } else {
+    return Err(type_error(
+      "Invalid FFI function type, expected null, integer, or BigInt",
+    ));
+  };
+  Ok(NativeValue { pointer })
+}
+
 fn ffi_parse_args<'scope>(
   scope: &mut v8::HandleScope<'scope>,
   args: serde_v8::Value<'scope>,
@@ -812,155 +1082,50 @@ where
   for (index, native_type) in parameter_types.iter().enumerate() {
     let value = args.get_index(scope, index as u32).unwrap();
     match native_type {
-      NativeType::Void => {
-        unreachable!();
-      }
       NativeType::U8 => {
-        let value = value
-          .uint32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI u8 type, expected number"))?
-          as u8;
-        ffi_args.push(NativeValue { u8_value: value });
+        ffi_args.push(ffi_parse_u8_arg(value)?);
       }
       NativeType::I8 => {
-        let value = value
-          .int32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI i8 type, expected number"))?
-          as i8;
-        ffi_args.push(NativeValue { i8_value: value });
+        ffi_args.push(ffi_parse_i8_arg(value)?);
       }
       NativeType::U16 => {
-        let value = value
-          .uint32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI u16 type, expected number"))?
-          as u16;
-        ffi_args.push(NativeValue { u16_value: value });
+        ffi_args.push(ffi_parse_u16_arg(value)?);
       }
       NativeType::I16 => {
-        let value = value
-          .int32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI i16 type, expected number"))?
-          as i16;
-        ffi_args.push(NativeValue { i16_value: value });
+        ffi_args.push(ffi_parse_i16_arg(value)?);
       }
       NativeType::U32 => {
-        let value = value
-          .uint32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI u32 type, expected number"))?
-          as u32;
-        ffi_args.push(NativeValue { u32_value: value });
+        ffi_args.push(ffi_parse_u32_arg(value)?);
       }
       NativeType::I32 => {
-        let value = value
-          .int32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI i32 type, expected number"))?
-          as i32;
-        ffi_args.push(NativeValue { i32_value: value });
+        ffi_args.push(ffi_parse_i32_arg(value)?);
       }
       NativeType::U64 => {
-        let value: u64 =
-          if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-            value.u64_value().0
-          } else {
-            value.integer_value(scope).ok_or_else(|| {
-              type_error("Invalid FFI u64 type, expected number")
-            })? as u64
-          };
-        ffi_args.push(NativeValue { u64_value: value });
+        ffi_args.push(ffi_parse_u64_arg(scope, value)?);
       }
       NativeType::I64 => {
-        let value: i64 =
-          if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-            value.i64_value().0
-          } else {
-            value.integer_value(scope).ok_or_else(|| {
-              type_error("Invalid FFI i64 type, expected number")
-            })? as i64
-          };
-        ffi_args.push(NativeValue { i64_value: value });
+        ffi_args.push(ffi_parse_i64_arg(scope, value)?);
       }
       NativeType::USize => {
-        let value: usize =
-          if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-            value.u64_value().0 as usize
-          } else {
-            value.integer_value(scope).ok_or_else(|| {
-              type_error("Invalid FFI usize type, expected number")
-            })? as usize
-          };
-        ffi_args.push(NativeValue { usize_value: value });
+        ffi_args.push(ffi_parse_usize_arg(scope, value)?);
       }
       NativeType::ISize => {
-        let value: isize =
-          if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-            value.i64_value().0 as isize
-          } else {
-            value.integer_value(scope).ok_or_else(|| {
-              type_error("Invalid FFI isize type, expected number")
-            })? as isize
-          };
-        ffi_args.push(NativeValue { isize_value: value });
+        ffi_args.push(ffi_parse_isize_arg(scope, value)?);
       }
       NativeType::F32 => {
-        let value = value
-          .number_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI f32 type, expected number"))?
-          as f32;
-        ffi_args.push(NativeValue { f32_value: value });
+        ffi_args.push(ffi_parse_f32_arg(value)?);
       }
       NativeType::F64 => {
-        let value = value
-          .number_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI f64 type, expected number"))?
-          as f64;
-        ffi_args.push(NativeValue { f64_value: value });
+        ffi_args.push(ffi_parse_f64_arg(value)?);
       }
       NativeType::Pointer => {
-        if value.is_null() {
-          let value: *const u8 = ptr::null();
-          ffi_args.push(NativeValue { pointer: value })
-        } else if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-          let value = value.u64_value().0 as *const u8;
-          ffi_args.push(NativeValue { pointer: value });
-        } else if let Ok(value) =
-          v8::Local::<v8::ArrayBufferView>::try_from(value)
-        {
-          let byte_offset = value.byte_offset();
-          let backing_store = value
-            .buffer(scope)
-            .ok_or_else(|| {
-              type_error(
-                "Invalid FFI ArrayBufferView, expected data in the buffer",
-              )
-            })?
-            .get_backing_store();
-          let pointer = if byte_offset > 0 {
-            &backing_store[byte_offset..] as *const _ as *const u8
-          } else {
-            &backing_store[..] as *const _ as *const u8
-          };
-          ffi_args.push(NativeValue { pointer });
-        } else if let Ok(value) = v8::Local::<v8::ArrayBuffer>::try_from(value)
-        {
-          let backing_store = value.get_backing_store();
-          let pointer = &backing_store[..] as *const _ as *const u8;
-          ffi_args.push(NativeValue { pointer });
-        } else {
-          return Err(type_error("Invalid FFI pointer type, expected null, BigInt, ArrayBuffer, or ArrayBufferView"));
-        }
+        ffi_args.push(ffi_parse_pointer_arg(scope, value)?);
       }
       NativeType::Function => {
-        if value.is_null() {
-          let value: *const u8 = ptr::null();
-          ffi_args.push(NativeValue { pointer: value })
-        } else if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-          let value = value.u64_value().0 as *const u8;
-          ffi_args.push(NativeValue { pointer: value });
-        } else {
-          return Err(type_error(
-            "Invalid FFI function type, expected null, or BigInt",
-          ));
-        }
+        ffi_args.push(ffi_parse_function_arg(scope, value)?);
+      }
+      NativeType::Void => {
+        unreachable!();
       }
     }
   }
@@ -990,169 +1155,50 @@ where
   for (index, native_type) in parameter_types.iter().enumerate() {
     let value = args.get(index as i32);
     match native_type {
-      NativeType::Void => {
-        unreachable!();
-      }
       NativeType::U8 => {
-        let value = value
-          .uint32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI u8 type, expected number"))?
-          as u8;
-        ffi_args.push(NativeValue { u8_value: value });
+        ffi_args.push(ffi_parse_u8_arg(value)?);
       }
       NativeType::I8 => {
-        let value = value
-          .int32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI i8 type, expected number"))?
-          as i8;
-
-        ffi_args.push(NativeValue { i8_value: value });
+        ffi_args.push(ffi_parse_i8_arg(value)?);
       }
       NativeType::U16 => {
-        let value = value
-          .uint32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI u16 type, expected number"))?
-          as u16;
-
-        ffi_args.push(NativeValue { u16_value: value });
+        ffi_args.push(ffi_parse_u16_arg(value)?);
       }
       NativeType::I16 => {
-        let value = value
-          .int32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI i16 type, expected number"))?
-          as i16;
-
-        ffi_args.push(NativeValue { i16_value: value });
+        ffi_args.push(ffi_parse_i16_arg(value)?);
       }
       NativeType::U32 => {
-        let value = value
-          .uint32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI u32 type, expected number"))?
-          as u32;
-
-        ffi_args.push(NativeValue { u32_value: value });
+        ffi_args.push(ffi_parse_u32_arg(value)?);
       }
       NativeType::I32 => {
-        let value = value
-          .int32_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI i32 type, expected number"))?
-          as i32;
-
-        ffi_args.push(NativeValue { i32_value: value });
+        ffi_args.push(ffi_parse_i32_arg(value)?);
       }
       NativeType::U64 => {
-        let value: u64 =
-          if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-            value.u64_value().0
-          } else {
-            value.integer_value(scope).ok_or_else(|| {
-              type_error("Invalid FFI u64 type, expected number")
-            })? as u64
-          };
-
-        ffi_args.push(NativeValue { u64_value: value });
+        ffi_args.push(ffi_parse_u64_arg(scope, value)?);
       }
       NativeType::I64 => {
-        let value: i64 =
-          if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-            value.i64_value().0
-          } else {
-            value.integer_value(scope).ok_or_else(|| {
-              type_error("Invalid FFI i64 type, expected number")
-            })? as i64
-          };
-
-        ffi_args.push(NativeValue { i64_value: value });
+        ffi_args.push(ffi_parse_i64_arg(scope, value)?);
       }
       NativeType::USize => {
-        let value: usize =
-          if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-            value.u64_value().0 as usize
-          } else {
-            value.integer_value(scope).ok_or_else(|| {
-              type_error("Invalid FFI usize type, expected number")
-            })? as usize
-          };
-
-        ffi_args.push(NativeValue { usize_value: value });
+        ffi_args.push(ffi_parse_usize_arg(scope, value)?);
       }
       NativeType::ISize => {
-        let value: isize =
-          if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-            value.i64_value().0 as isize
-          } else {
-            value.integer_value(scope).ok_or_else(|| {
-              type_error("Invalid FFI isize type, expected number")
-            })? as isize
-          };
-
-        ffi_args.push(NativeValue { isize_value: value });
+        ffi_args.push(ffi_parse_isize_arg(scope, value)?);
       }
       NativeType::F32 => {
-        let value = value
-          .number_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI f32 type, expected number"))?
-          as f32;
-
-        ffi_args.push(NativeValue { f32_value: value });
+        ffi_args.push(ffi_parse_f32_arg(value)?);
       }
       NativeType::F64 => {
-        let value = value
-          .number_value(scope)
-          .ok_or_else(|| type_error("Invalid FFI f64 type, expected number"))?
-          as f64;
-        ffi_args.push(NativeValue { f64_value: value });
+        ffi_args.push(ffi_parse_f64_arg(value)?);
       }
       NativeType::Pointer => {
-        if value.is_null() {
-          let value: *const u8 = ptr::null();
-
-          ffi_args.push(NativeValue { pointer: value })
-        } else if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-          let value = value.u64_value().0 as *const u8;
-
-          ffi_args.push(NativeValue { pointer: value });
-        } else if let Ok(value) =
-          v8::Local::<v8::ArrayBufferView>::try_from(value)
-        {
-          let byte_offset = value.byte_offset();
-          let backing_store = value
-            .buffer(scope)
-            .ok_or_else(|| {
-              type_error(
-                "Invalid FFI ArrayBufferView, expected data in the buffer",
-              )
-            })?
-            .get_backing_store();
-          let pointer = if byte_offset > 0 {
-            &backing_store[byte_offset..] as *const _ as *const u8
-          } else {
-            &backing_store[..] as *const _ as *const u8
-          };
-
-          ffi_args.push(NativeValue { pointer });
-        } else if let Ok(value) = v8::Local::<v8::ArrayBuffer>::try_from(value)
-        {
-          let backing_store = value.get_backing_store();
-          let pointer = &backing_store[..] as *const _ as *const u8;
-
-          ffi_args.push(NativeValue { pointer });
-        } else {
-          return Err(type_error("Invalid FFI pointer type, expected null, BigInt, ArrayBuffer, or ArrayBufferView"));
-        }
+        ffi_args.push(ffi_parse_pointer_arg(scope, value)?);
       }
       NativeType::Function => {
-        if value.is_null() {
-          let value: *const u8 = ptr::null();
-          ffi_args.push(NativeValue { pointer: value })
-        } else if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-          let value = value.u64_value().0 as *const u8;
-          ffi_args.push(NativeValue { pointer: value });
-        } else {
-          return Err(type_error(
-            "Invalid FFI function type, expected null, or BigInt",
-          ));
-        }
+        ffi_args.push(ffi_parse_function_arg(scope, value)?);
+      }
+      NativeType::Void => {
+        unreachable!();
       }
     }
   }
@@ -1373,8 +1419,8 @@ unsafe fn do_ffi_callback(
   // it somehow cannot change the values that the loop sees, even if they both
   // refer the same `let bool_value`.
   let mut cb_scope = v8::CallbackScope::new(context);
-  let mut scope = v8::HandleScope::new(&mut cb_scope);
-  let func = callback.open(&mut scope);
+  let scope = &mut v8::HandleScope::new(&mut cb_scope);
+  let func = callback.open(scope);
   let result = result as *mut c_void;
   let repr: &[*mut ffi_type] =
     std::slice::from_raw_parts(cif.arg_types, cif.nargs as usize);
@@ -1386,45 +1432,62 @@ unsafe fn do_ffi_callback(
     let value: v8::Local<v8::Value> = match (*(*repr)).type_ as _ {
       FFI_TYPE_FLOAT => {
         let value = *((*val) as *const f32);
-        v8::Number::new(&mut scope, value as f64).into()
+        v8::Number::new(scope, value as f64).into()
       }
       FFI_TYPE_DOUBLE => {
         let value = *((*val) as *const f64);
-        v8::Number::new(&mut scope, value).into()
+        v8::Number::new(scope, value).into()
       }
       FFI_TYPE_SINT8 => {
         let value = *((*val) as *const i8);
-        v8::Integer::new(&mut scope, value as i32).into()
+        v8::Integer::new(scope, value as i32).into()
       }
       FFI_TYPE_UINT8 => {
         let value = *((*val) as *const u8);
-        v8::Integer::new_from_unsigned(&mut scope, value as u32).into()
+        v8::Integer::new_from_unsigned(scope, value as u32).into()
       }
       FFI_TYPE_SINT16 => {
         let value = *((*val) as *const i16);
-        v8::Integer::new(&mut scope, value as i32).into()
+        v8::Integer::new(scope, value as i32).into()
       }
       FFI_TYPE_UINT16 => {
         let value = *((*val) as *const u16);
-        v8::Integer::new_from_unsigned(&mut scope, value as u32).into()
+        v8::Integer::new_from_unsigned(scope, value as u32).into()
       }
       FFI_TYPE_INT | FFI_TYPE_SINT32 => {
         let value = *((*val) as *const i32);
-        v8::Integer::new(&mut scope, value).into()
+        v8::Integer::new(scope, value).into()
       }
       FFI_TYPE_UINT32 => {
         let value = *((*val) as *const u32);
-        v8::Integer::new_from_unsigned(&mut scope, value).into()
+        v8::Integer::new_from_unsigned(scope, value).into()
       }
       FFI_TYPE_SINT64 => {
         let result = *((*val) as *const i64);
-        v8::BigInt::new_from_i64(&mut scope, result).into()
+        if result > MAX_SAFE_INTEGER as i64 || result < MIN_SAFE_INTEGER as i64
+        {
+          v8::BigInt::new_from_i64(scope, result).into()
+        } else {
+          v8::Number::new(scope, result as f64).into()
+        }
       }
-      FFI_TYPE_POINTER | FFI_TYPE_STRUCT | FFI_TYPE_UINT64 => {
+      FFI_TYPE_UINT64 => {
         let result = *((*val) as *const u64);
-        v8::BigInt::new_from_u64(&mut scope, result).into()
+        if result > MAX_SAFE_INTEGER as u64 {
+          v8::BigInt::new_from_u64(scope, result).into()
+        } else {
+          v8::Number::new(scope, result as f64).into()
+        }
       }
-      FFI_TYPE_VOID => v8::undefined(&mut scope).into(),
+      FFI_TYPE_POINTER | FFI_TYPE_STRUCT => {
+        let result = *((*val) as *const u64);
+        if result > MAX_SAFE_INTEGER as u64 {
+          v8::BigInt::new_from_u64(scope, result).into()
+        } else {
+          v8::Number::new(scope, result as f64).into()
+        }
+      }
+      FFI_TYPE_VOID => v8::undefined(scope).into(),
       _ => {
         unreachable!()
       }
@@ -1432,8 +1495,8 @@ unsafe fn do_ffi_callback(
     params.push(value);
   }
 
-  let recv = v8::undefined(&mut scope);
-  let call_result = func.call(&mut scope, recv.into(), &params);
+  let recv = v8::undefined(scope);
+  let call_result = func.call(scope, recv.into(), &params);
   std::mem::forget(callback);
 
   if call_result.is_none() {
@@ -1461,7 +1524,7 @@ unsafe fn do_ffi_callback(
       }
       FFI_TYPE_POINTER | FFI_TYPE_STRUCT | FFI_TYPE_UINT64
       | FFI_TYPE_SINT64 => {
-        *(result as *mut u64) = 0;
+        *(result as *mut usize) = 0;
       }
       FFI_TYPE_VOID => {
         // nop
@@ -1477,87 +1540,134 @@ unsafe fn do_ffi_callback(
 
   match (*cif.rtype).type_ as _ {
     FFI_TYPE_INT | FFI_TYPE_SINT32 => {
-      *(result as *mut i32) = value
-        .int32_value(&mut scope)
-        .expect("Unable to deserialize result parameter.")
-        as i32;
+      let value = if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        value.value() as i32
+      } else {
+        // Fallthrough, probably UB.
+        value
+          .int32_value(scope)
+          .expect("Unable to deserialize result parameter.") as i32
+      };
+      *(result as *mut i32) = value;
     }
     FFI_TYPE_FLOAT => {
-      *(result as *mut f32) = value
-        .number_value(&mut scope)
-        .expect("Unable to deserialize result parameter.")
-        as f32;
+      let value = if let Ok(value) = v8::Local::<v8::Number>::try_from(value) {
+        value.value() as f32
+      } else {
+        // Fallthrough, probably UB.
+        value
+          .number_value(scope)
+          .expect("Unable to deserialize result parameter.") as f32
+      };
+      *(result as *mut f32) = value;
     }
     FFI_TYPE_DOUBLE => {
-      *(result as *mut f64) = value
-        .number_value(&mut scope)
-        .expect("Unable to deserialize result parameter.");
+      let value = if let Ok(value) = v8::Local::<v8::Number>::try_from(value) {
+        value.value()
+      } else {
+        // Fallthrough, probably UB.
+        value
+          .number_value(scope)
+          .expect("Unable to deserialize result parameter.")
+      };
+      *(result as *mut f64) = value;
     }
     FFI_TYPE_POINTER | FFI_TYPE_STRUCT => {
-      if let Ok(value) = v8::Local::<v8::ArrayBufferView>::try_from(value) {
+      let pointer = if let Ok(value) =
+        v8::Local::<v8::ArrayBufferView>::try_from(value)
+      {
         let byte_offset = value.byte_offset();
         let backing_store = value
-          .buffer(&mut scope)
+          .buffer(scope)
           .expect("Unable to deserialize result parameter.")
           .get_backing_store();
-        let pointer = if byte_offset > 0 {
+        if byte_offset > 0 {
           &backing_store[byte_offset..] as *const _ as *const u8
         } else {
           &backing_store[..] as *const _ as *const u8
-        };
-        *(result as *mut *const u8) = pointer;
+        }
+      } else if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
+        value.u64_value().0 as usize as *const u8
       } else if let Ok(value) = v8::Local::<v8::ArrayBuffer>::try_from(value) {
         let backing_store = value.get_backing_store();
-        let pointer = &backing_store[..] as *const _ as *const u8;
-        *(result as *mut *const u8) = pointer;
-      } else if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
-        *(result as *mut u64) = value.u64_value().0;
+        &backing_store[..] as *const _ as *const u8
+      } else if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        value.value() as usize as *const u8
       } else if value.is_null() {
-        *(result as *mut *const c_void) = ptr::null();
+        ptr::null()
       } else {
         // Fallthrough: Probably someone returned a number but this could
         // also be eg. a string. This is essentially UB.
-        *(result as *mut u64) = value
-          .integer_value(&mut scope)
-          .expect("Unable to deserialize result parameter.")
-          as u64;
-      }
+        value
+          .integer_value(scope)
+          .expect("Unable to deserialize result parameter.") as usize
+          as *const u8
+      };
+      *(result as *mut *const u8) = pointer;
     }
     FFI_TYPE_SINT8 => {
-      *(result as *mut i8) = value
-        .int32_value(&mut scope)
-        .expect("Unable to deserialize result parameter.")
-        as i8;
+      let value = if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        value.value() as i8
+      } else {
+        // Fallthrough, essentially UB.
+        value
+          .int32_value(scope)
+          .expect("Unable to deserialize result parameter.") as i8
+      };
+      *(result as *mut i8) = value;
     }
     FFI_TYPE_UINT8 => {
-      *(result as *mut u8) = value
-        .uint32_value(&mut scope)
-        .expect("Unable to deserialize result parameter.")
-        as u8;
+      let value = if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        value.value() as u8
+      } else {
+        // Fallthrough, essentially UB.
+        value
+          .uint32_value(scope)
+          .expect("Unable to deserialize result parameter.") as u8
+      };
+      *(result as *mut u8) = value;
     }
     FFI_TYPE_SINT16 => {
-      *(result as *mut i16) = value
-        .int32_value(&mut scope)
-        .expect("Unable to deserialize result parameter.")
-        as i16;
+      let value = if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        value.value() as i16
+      } else {
+        // Fallthrough, essentially UB.
+        value
+          .int32_value(scope)
+          .expect("Unable to deserialize result parameter.") as i16
+      };
+      *(result as *mut i16) = value;
     }
     FFI_TYPE_UINT16 => {
-      *(result as *mut u16) = value
-        .uint32_value(&mut scope)
-        .expect("Unable to deserialize result parameter.")
-        as u16;
+      let value = if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        value.value() as u16
+      } else {
+        // Fallthrough, essentially UB.
+        value
+          .uint32_value(scope)
+          .expect("Unable to deserialize result parameter.") as u16
+      };
+      *(result as *mut u16) = value;
     }
     FFI_TYPE_UINT32 => {
-      *(result as *mut u32) = value
-        .uint32_value(&mut scope)
-        .expect("Unable to deserialize result parameter.");
+      let value = if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        value.value() as u32
+      } else {
+        // Fallthrough, essentially UB.
+        value
+          .uint32_value(scope)
+          .expect("Unable to deserialize result parameter.")
+      };
+      *(result as *mut u32) = value;
     }
     FFI_TYPE_SINT64 => {
       if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
         *(result as *mut i64) = value.i64_value().0;
+      } else if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        *(result as *mut i64) = value.value();
       } else {
         *(result as *mut i64) = value
-          .integer_value(&mut scope)
+          .integer_value(scope)
           .expect("Unable to deserialize result parameter.")
           as i64;
       }
@@ -1565,9 +1675,11 @@ unsafe fn do_ffi_callback(
     FFI_TYPE_UINT64 => {
       if let Ok(value) = v8::Local::<v8::BigInt>::try_from(value) {
         *(result as *mut u64) = value.u64_value().0;
+      } else if let Ok(value) = v8::Local::<v8::Integer>::try_from(value) {
+        *(result as *mut u64) = value.value() as u64;
       } else {
         *(result as *mut u64) = value
-          .integer_value(&mut scope)
+          .integer_value(scope)
           .expect("Unable to deserialize result parameter.")
           as u64;
       }
@@ -1629,15 +1741,19 @@ where
   );
 
   let closure = libffi::middle::Closure::new(cif, deno_ffi_callback, info);
-  let ptr = *closure.code_ptr() as usize as u64;
+  let ptr = *closure.code_ptr() as usize;
   let resource = UnsafeCallbackResource { closure, info };
   let rid = state.resource_table.add(resource);
 
   let rid_local = v8::Integer::new_from_unsigned(scope, rid);
-  let ptr_local = v8::BigInt::new_from_u64(scope, ptr);
+  let ptr_local: v8::Local<v8::Value> = if ptr > MAX_SAFE_INTEGER as usize {
+    v8::BigInt::new_from_u64(scope, ptr as u64).into()
+  } else {
+    v8::Number::new(scope, ptr as f64).into()
+  };
   let array = v8::Array::new(scope, 2);
   array.set_index(scope, 0, rid_local.into());
-  array.set_index(scope, 1, ptr_local.into());
+  array.set_index(scope, 1, ptr_local);
   let array_value: v8::Local<v8::Value> = array.into();
 
   Ok(array_value.into())
@@ -1647,7 +1763,7 @@ where
 fn op_ffi_call_ptr<FP, 'scope>(
   scope: &mut v8::HandleScope<'scope>,
   state: Rc<RefCell<deno_core::OpState>>,
-  pointer: u64,
+  pointer: usize,
   def: ForeignFunction,
   parameters: serde_v8::Value<'scope>,
 ) -> Result<serde_v8::Value<'scope>, AnyError>
@@ -1690,7 +1806,7 @@ fn op_ffi_unsafe_callback_ref(state: &mut deno_core::OpState, inc_dec: bool) {
 fn op_ffi_call_ptr_nonblocking<'scope, FP>(
   scope: &mut v8::HandleScope<'scope>,
   state: Rc<RefCell<deno_core::OpState>>,
-  pointer: u64,
+  pointer: usize,
   def: ForeignFunction,
   parameters: serde_v8::Value<'scope>,
 ) -> Result<impl Future<Output = Result<Value, AnyError>>, AnyError>
@@ -1781,30 +1897,46 @@ fn op_ffi_get_static<'scope>(
     NativeType::U64 => {
       // SAFETY: ptr is user provided
       let result = unsafe { ptr::read_unaligned(data_ptr as *const u64) };
-      let big_int: v8::Local<v8::Value> =
-        v8::BigInt::new_from_u64(scope, result).into();
-      big_int.into()
+      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as u64 {
+        v8::BigInt::new_from_u64(scope, result).into()
+      } else {
+        v8::Number::new(scope, result as f64).into()
+      };
+      integer.into()
     }
     NativeType::I64 => {
       // SAFETY: ptr is user provided
       let result = unsafe { ptr::read_unaligned(data_ptr as *const i64) };
-      let big_int: v8::Local<v8::Value> =
-        v8::BigInt::new_from_i64(scope, result).into();
-      big_int.into()
+      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as i64
+        || result < MIN_SAFE_INTEGER as i64
+      {
+        v8::BigInt::new_from_i64(scope, result).into()
+      } else {
+        v8::Number::new(scope, result as f64).into()
+      };
+      integer.into()
     }
     NativeType::USize => {
       // SAFETY: ptr is user provided
       let result = unsafe { ptr::read_unaligned(data_ptr as *const usize) };
-      let big_int: v8::Local<v8::Value> =
-        v8::BigInt::new_from_u64(scope, result as u64).into();
-      big_int.into()
+      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as usize
+      {
+        v8::BigInt::new_from_u64(scope, result as u64).into()
+      } else {
+        v8::Number::new(scope, result as f64).into()
+      };
+      integer.into()
     }
     NativeType::ISize => {
       // SAFETY: ptr is user provided
       let result = unsafe { ptr::read_unaligned(data_ptr as *const isize) };
-      let big_int: v8::Local<v8::Value> =
-        v8::BigInt::new_from_i64(scope, result as i64).into();
-      big_int.into()
+      let integer: v8::Local<v8::Value> =
+        if result > MAX_SAFE_INTEGER || result < MIN_SAFE_INTEGER {
+          v8::BigInt::new_from_i64(scope, result as i64).into()
+        } else {
+          v8::Number::new(scope, result as f64).into()
+        };
+      integer.into()
     }
     NativeType::F32 => {
       // SAFETY: ptr is user provided
@@ -1821,9 +1953,12 @@ fn op_ffi_get_static<'scope>(
     }
     NativeType::Pointer | NativeType::Function => {
       let result = data_ptr as u64;
-      let big_int: v8::Local<v8::Value> =
-        v8::BigInt::new_from_u64(scope, result).into();
-      big_int.into()
+      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as u64 {
+        v8::BigInt::new_from_u64(scope, result).into()
+      } else {
+        v8::Number::new(scope, result as f64).into()
+      };
+      integer.into()
     }
   })
 }
@@ -1908,9 +2043,13 @@ where
     ));
   };
 
-  let big_int: v8::Local<v8::Value> =
-    v8::BigInt::new_from_u64(scope, pointer as u64).into();
-  Ok(big_int.into())
+  let integer: v8::Local<v8::Value> =
+    if pointer as usize > MAX_SAFE_INTEGER as usize {
+      v8::BigInt::new_from_u64(scope, pointer as u64).into()
+    } else {
+      v8::Number::new(scope, pointer as usize as f64).into()
+    };
+  Ok(integer.into())
 }
 
 unsafe extern "C" fn noop_deleter_callback(
@@ -1935,9 +2074,14 @@ where
   let permissions = state.borrow_mut::<FP>();
   permissions.check(None)?;
 
-  let value = v8::Local::<v8::BigInt>::try_from(src.v8_value)
-    .map_err(|_| type_error("Invalid FFI pointer value, expected BigInt"))?;
-  let ptr = value.u64_value().0 as usize as *mut c_void;
+  let ptr = if let Ok(value) = v8::Local::<v8::Number>::try_from(src.v8_value) {
+    value.value() as usize as *mut c_void
+  } else if let Ok(value) = v8::Local::<v8::BigInt>::try_from(src.v8_value) {
+    value.u64_value().0 as usize as *mut c_void
+  } else {
+    return Err(type_error("Invalid FFI pointer value, expected BigInt"));
+  };
+
   if std::ptr::eq(ptr, std::ptr::null()) {
     return Err(type_error("Invalid FFI pointer value, got nullptr"));
   }
@@ -1960,7 +2104,7 @@ where
 #[op]
 fn op_ffi_buf_copy_into<FP>(
   state: &mut deno_core::OpState,
-  src: u64,
+  src: usize,
   mut dst: ZeroCopyBuf,
   len: usize,
 ) -> Result<(), AnyError>
@@ -1989,7 +2133,7 @@ where
 fn op_ffi_cstr_read<FP, 'scope>(
   scope: &mut v8::HandleScope<'scope>,
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<serde_v8::Value<'scope>, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2013,7 +2157,7 @@ where
 #[op]
 fn op_ffi_read_u8<FP>(
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<u8, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2030,7 +2174,7 @@ where
 #[op]
 fn op_ffi_read_i8<FP>(
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<i8, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2047,7 +2191,7 @@ where
 #[op]
 fn op_ffi_read_u16<FP>(
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<u16, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2064,7 +2208,7 @@ where
 #[op]
 fn op_ffi_read_i16<FP>(
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<i16, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2081,7 +2225,7 @@ where
 #[op]
 fn op_ffi_read_u32<FP>(
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<u32, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2098,7 +2242,7 @@ where
 #[op]
 fn op_ffi_read_i32<FP>(
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<i32, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2116,7 +2260,7 @@ where
 fn op_ffi_read_u64<FP, 'scope>(
   scope: &mut v8::HandleScope<'scope>,
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<serde_v8::Value<'scope>, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2130,15 +2274,47 @@ where
   // SAFETY: ptr is user provided.
   let result = unsafe { ptr::read_unaligned(ptr as *const u64) };
 
-  let big_int: v8::Local<v8::Value> =
-    v8::BigInt::new_from_u64(scope, result).into();
-  Ok(big_int.into())
+  let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as u64 {
+    v8::BigInt::new_from_u64(scope, result).into()
+  } else {
+    v8::Number::new(scope, result as f64).into()
+  };
+
+  Ok(integer.into())
+}
+
+#[op(v8)]
+fn op_ffi_read_i64<FP, 'scope>(
+  scope: &mut v8::HandleScope<'scope>,
+  state: &mut deno_core::OpState,
+  ptr: usize,
+) -> Result<serde_v8::Value<'scope>, AnyError>
+where
+  FP: FfiPermissions + 'static,
+  'scope: 'scope,
+{
+  check_unstable(state, "Deno.UnsafePointerView#getBigUint64");
+
+  let permissions = state.borrow_mut::<FP>();
+  permissions.check(None)?;
+
+  // SAFETY: ptr is user provided.
+  let result = unsafe { ptr::read_unaligned(ptr as *const i64) };
+
+  let integer: v8::Local<v8::Value> =
+    if result > MAX_SAFE_INTEGER as i64 || result < MIN_SAFE_INTEGER as i64 {
+      v8::BigInt::new_from_i64(scope, result).into()
+    } else {
+      v8::Number::new(scope, result as f64).into()
+    };
+
+  Ok(integer.into())
 }
 
 #[op]
 fn op_ffi_read_f32<FP>(
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<f32, AnyError>
 where
   FP: FfiPermissions + 'static,
@@ -2155,7 +2331,7 @@ where
 #[op]
 fn op_ffi_read_f64<FP>(
   state: &mut deno_core::OpState,
-  ptr: u64,
+  ptr: usize,
 ) -> Result<f64, AnyError>
 where
   FP: FfiPermissions + 'static,