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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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44
crates/runtime/src/libcalls.rs
View File

@@ -57,10 +57,12 @@
//! ```
use crate::externref::VMExternRef;
use crate::table::{Table, TableElement};
use crate::table::Table;
use crate::traphandlers::raise_lib_trap;
use crate::vmcontext::VMContext;
use wasmtime_environ::wasm::{DataIndex, DefinedMemoryIndex, ElemIndex, MemoryIndex, TableIndex};
use crate::vmcontext::{VMCallerCheckedAnyfunc, VMContext};
use wasmtime_environ::wasm::{
DataIndex, DefinedMemoryIndex, ElemIndex, MemoryIndex, TableElementType, TableIndex,
};
/// Implementation of f32.ceil
pub extern "C" fn wasmtime_f32_ceil(x: f32) -> f32 {
@@ -226,24 +228,38 @@ pub unsafe extern "C" fn wasmtime_imported_memory32_size(
instance.imported_memory_size(memory_index)
}
/// Implementation of `table.grow` for `externref`s.
pub unsafe extern "C" fn wasmtime_table_grow_extern_ref(
/// Implementation of `table.grow`.
pub unsafe extern "C" fn wasmtime_table_grow(
vmctx: *mut VMContext,
table_index: u32,
delta: u32,
// NB: we don't know whether this is a pointer to a `VMCallerCheckedAnyfunc`
// or is a `VMExternRef` until we look at the table type.
init_value: *mut u8,
) -> u32 {
let init_value = if init_value.is_null() {
None
} else {
Some(VMExternRef::clone_from_raw(init_value))
};
let instance = (&mut *vmctx).instance();
let table_index = TableIndex::from_u32(table_index);
instance
.table_grow(table_index, delta, TableElement::ExternRef(init_value))
.unwrap_or(-1_i32 as u32)
match instance.table_element_type(table_index) {
TableElementType::Func => {
let func = init_value as *mut VMCallerCheckedAnyfunc;
instance
.table_grow(table_index, delta, func.into())
.unwrap_or(-1_i32 as u32)
}
TableElementType::Val(ty) => {
debug_assert_eq!(ty, crate::ref_type());
let init_value = if init_value.is_null() {
None
} else {
Some(VMExternRef::clone_from_raw(init_value))
};
instance
.table_grow(table_index, delta, init_value.into())
.unwrap_or(-1_i32 as u32)
}
}
}
/// Implementation of `table.copy`.