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wasmtime: Add support for func.ref and table.grow with funcrefs

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`funcref`s are implemented as `NonNull<VMCallerCheckedAnyfunc>`.

This should be more efficient than using a `VMExternRef` that points at a
`VMCallerCheckedAnyfunc` because it gets rid of an indirection, dynamic
allocation, and some reference counting.

Note that the null function reference is *NOT* a null pointer; it is a
`VMCallerCheckedAnyfunc` that has a null `func_ptr` member.

Part of #929
This commit is contained in:
Nick Fitzgerald
2020-06-18 11:04:40 -07:00
parent ddc2ce8080
commit 58bb5dd953
37 changed files with 603 additions and 305 deletions
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23
crates/runtime/src/vmcontext.rs
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@@ -3,8 +3,9 @@
use crate::instance::Instance;
use std::any::Any;
use std::ptr::NonNull;
use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
use std::{ptr, u32};
use std::u32;
use wasmtime_environ::BuiltinFunctionIndex;
/// An imported function.
@@ -12,7 +13,7 @@ use wasmtime_environ::BuiltinFunctionIndex;
#[repr(C)]
pub struct VMFunctionImport {
/// A pointer to the imported function body.
pub body: *const VMFunctionBody,
pub body: NonNull<VMFunctionBody>,
/// A pointer to the `VMContext` that owns the function.
pub vmctx: *mut VMContext,
@@ -475,7 +476,7 @@ impl Default for VMSharedSignatureIndex {
#[repr(C)]
pub struct VMCallerCheckedAnyfunc {
/// Function body.
pub func_ptr: *const VMFunctionBody,
pub func_ptr: NonNull<VMFunctionBody>,
/// Function signature id.
pub type_index: VMSharedSignatureIndex,
/// Function `VMContext`.
@@ -513,16 +514,6 @@ mod test_vmcaller_checked_anyfunc {
}
}
impl Default for VMCallerCheckedAnyfunc {
fn default() -> Self {
Self {
func_ptr: ptr::null_mut(),
type_index: Default::default(),
vmctx: ptr::null_mut(),
}
}
}
/// An array that stores addresses of builtin functions. We translate code
/// to use indirect calls. This way, we don't have to patch the code.
#[repr(C)]
@@ -549,8 +540,10 @@ impl VMBuiltinFunctionsArray {
ptrs[BuiltinFunctionIndex::imported_memory32_size().index() as usize] =
wasmtime_imported_memory32_size as usize;
ptrs[BuiltinFunctionIndex::table_copy().index() as usize] = wasmtime_table_copy as usize;
ptrs[BuiltinFunctionIndex::table_grow_extern_ref().index() as usize] =
wasmtime_table_grow_extern_ref as usize;
ptrs[BuiltinFunctionIndex::table_grow_funcref().index() as usize] =
wasmtime_table_grow as usize;
ptrs[BuiltinFunctionIndex::table_grow_externref().index() as usize] =
wasmtime_table_grow as usize;
ptrs[BuiltinFunctionIndex::table_init().index() as usize] = wasmtime_table_init as usize;
ptrs[BuiltinFunctionIndex::elem_drop().index() as usize] = wasmtime_elem_drop as usize;
ptrs[BuiltinFunctionIndex::defined_memory_copy().index() as usize] =