wasmtime_environ/gc/
null.rs

1//! Layout of Wasm GC objects in the  null garbage collector.
2
3use super::*;
4
5/// The size of the `VMNullHeader` header for GC objects.
6pub const HEADER_SIZE: u32 = 8;
7
8/// The align of the `VMNullHeader` header for GC objects.
9pub const HEADER_ALIGN: u32 = 8;
10
11/// The offset of the length field in a `VMNullArrayHeader`.
12pub const ARRAY_LENGTH_OFFSET: u32 = HEADER_SIZE;
13
14/// The offset of the tag-instance-index field in an exception header.
15pub const EXCEPTION_TAG_INSTANCE_OFFSET: u32 = HEADER_SIZE;
16
17/// The offset of the tag-defined-index field in an exception header.
18pub const EXCEPTION_TAG_DEFINED_OFFSET: u32 = HEADER_SIZE + 4;
19
20/// The layout of Wasm GC objects in the null collector.
21#[derive(Default)]
22pub struct NullTypeLayouts;
23
24impl GcTypeLayouts for NullTypeLayouts {
25    fn array_length_field_offset(&self) -> u32 {
26        ARRAY_LENGTH_OFFSET
27    }
28
29    fn exception_tag_instance_offset(&self) -> u32 {
30        EXCEPTION_TAG_INSTANCE_OFFSET
31    }
32
33    fn exception_tag_defined_offset(&self) -> u32 {
34        EXCEPTION_TAG_DEFINED_OFFSET
35    }
36
37    fn array_layout(&self, ty: &WasmArrayType) -> GcArrayLayout {
38        common_array_layout(ty, HEADER_SIZE, HEADER_ALIGN, ARRAY_LENGTH_OFFSET)
39    }
40
41    fn struct_layout(&self, ty: &WasmStructType) -> GcStructLayout {
42        common_struct_layout(ty, HEADER_SIZE, HEADER_ALIGN)
43    }
44
45    fn exn_layout(&self, ty: &WasmExnType) -> GcStructLayout {
46        common_exn_layout(ty, HEADER_SIZE, HEADER_ALIGN)
47    }
48}
wasmtime_environ/gc/null.rs

wasmtime_environ/gc/
null.rs
