refactor(ext/ffi): split into multiple parts (#16950)

- [x] `dlfcn.rs` - `dlopen()`-related code.
- [x] `turbocall.rs` - Call trampoline JIT compiler. 
- [x] `repr.rs` - Pointer representation. Home of the UnsafePointerView
ops.
- [x] `symbol.rs` - Function symbol related code.
- [x] `callback.rs` - Home of `Deno.UnsafeCallback` ops.
- [x] `ir.rs` - Intermediate representation for values. Home of the
`NativeValue` type.
- [x] `call.rs` - Generic call ops. Home to everything related to
calling FFI symbols.
- [x] `static.rs` - static symbol support

I find easier to work with this setup, I eventually want to expand
TurboCall to unroll type conversion loop in generic calls, generate code
for individual symbols (lazy function pointers), etc.

1 files changed, 63 insertions, 0 deletions

diff --git a/ext/ffi/symbol.rs b/ext/ffi/symbol.rs
new file mode 100644
index 000000000..0248c1fff
--- /dev/null
+++ b/ext/ffi/symbol.rs
@@ -0,0 +1,63 @@
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+
+/// Defines the accepted types that can be used as
+/// parameters and return values in FFI.
+#[derive(Clone, Copy, Debug, serde::Deserialize, Eq, PartialEq)]
+#[serde(rename_all = "lowercase")]
+pub enum NativeType {
+  Void,
+  Bool,
+  U8,
+  I8,
+  U16,
+  I16,
+  U32,
+  I32,
+  U64,
+  I64,
+  USize,
+  ISize,
+  F32,
+  F64,
+  Pointer,
+  Buffer,
+  Function,
+}
+
+impl From<NativeType> for libffi::middle::Type {
+  fn from(native_type: NativeType) -> Self {
+    match native_type {
+      NativeType::Void => libffi::middle::Type::void(),
+      NativeType::U8 | NativeType::Bool => libffi::middle::Type::u8(),
+      NativeType::I8 => libffi::middle::Type::i8(),
+      NativeType::U16 => libffi::middle::Type::u16(),
+      NativeType::I16 => libffi::middle::Type::i16(),
+      NativeType::U32 => libffi::middle::Type::u32(),
+      NativeType::I32 => libffi::middle::Type::i32(),
+      NativeType::U64 => libffi::middle::Type::u64(),
+      NativeType::I64 => libffi::middle::Type::i64(),
+      NativeType::USize => libffi::middle::Type::usize(),
+      NativeType::ISize => libffi::middle::Type::isize(),
+      NativeType::F32 => libffi::middle::Type::f32(),
+      NativeType::F64 => libffi::middle::Type::f64(),
+      NativeType::Pointer | NativeType::Buffer | NativeType::Function => {
+        libffi::middle::Type::pointer()
+      }
+    }
+  }
+}
+
+#[derive(Clone)]
+pub struct Symbol {
+  pub cif: libffi::middle::Cif,
+  pub ptr: libffi::middle::CodePtr,
+  pub parameter_types: Vec<NativeType>,
+  pub result_type: NativeType,
+  pub can_callback: bool,
+}
+
+#[allow(clippy::non_send_fields_in_send_ty)]
+// SAFETY: unsafe trait must have unsafe implementation
+unsafe impl Send for Symbol {}
+// SAFETY: unsafe trait must have unsafe implementation
+unsafe impl Sync for Symbol {}