Now that ArrayBuffer/ArrayBufferView is a generic Value type, we have to
handle it being passed any value. To do this, thread
FastApiCallbackOptions through the function, and add error raising
logic.
If we run conversion and the value is not valid, we return `isize::MAX`,
and then in cranelift we use this value to know that we should branch to
the error logic.
An example compilation looks like this:
```rust
extern "C" fn print_buffer(ptr: *const u8, len: usize);
```
```clif
function %print_buffer_wrapper(i64, i64, i64, i64) system_v {
sig0 = (i64, i64) system_v
sig1 = (i64) -> i64 system_v
sig2 = (i64) system_v
block0(v0: i64, v1: i64, v2: i64, v3: i64):
v4 = iconst.i64 0x6525_9198_2d00 ; turbocall_ab_contents
v5 = call_indirect sig1, v4(v1)
v6 = iconst.i64 0x7fff_ffff_ffff_ffff
v7 = icmp eq v5, v6
brif v7, block1, block2
block2:
v8 = iconst.i64 0x7558_4c0c_0700 ; sym.ptr
call_indirect sig0, v8(v5, v2)
return
block1 cold:
v9 = iconst.i64 0x6525_9198_2d70 ; turbocall_raise
call_indirect sig2, v9(v3)
return
}
```
Also cleaned up all the `unwrap`s and added some logging.
This patch makes `NativeType` to `libffi::middle::Type` conversion
failliable and w.t disallows struct with empty fields. libffi does not
handle "empty" struct because they don't exist in C (or Rust).
Fixes #17481
Adds support for passing and returning structs as buffers to FFI. This does not implement fastapi support for structs. Needed for certain system APIs such as AppKit on macOS.
- [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.
