1 use crate::runtime::vm::{StoreBox, VMGlobalDefinition};
2 use crate::store::{AutoAssertNoGc, StoreOpaque};
3 use crate::type_registry::RegisteredType;
4 use crate::{GlobalType, Mutability, Result, RootedGcRefImpl, Val};
5 use core::ptr;
6 use wasmtime_environ::Global;
7
8 #[repr(C)]
9 pub struct VMHostGlobalContext {
10 pub(crate) ty: Global,
11 pub(crate) global: VMGlobalDefinition,
12
13 _registered_type: Option<RegisteredType>,
14 }
15
generate_global_export( store: &mut StoreOpaque, ty: GlobalType, val: Val, ) -> Result<crate::Global>16 pub fn generate_global_export(
17 store: &mut StoreOpaque,
18 ty: GlobalType,
19 val: Val,
20 ) -> Result<crate::Global> {
21 let global = wasmtime_environ::Global {
22 wasm_ty: ty.content().to_wasm_type(),
23 mutability: match ty.mutability() {
24 Mutability::Const => false,
25 Mutability::Var => true,
26 },
27 };
28 let ctx = StoreBox::new(VMHostGlobalContext {
29 ty: global,
30 global: VMGlobalDefinition::new(),
31 _registered_type: ty.into_registered_type(),
32 })?;
33
34 let mut store = AutoAssertNoGc::new(store);
35 // SAFETY: the global that this is pointing to is rooted in `ctx` above and
36 // is safe to initialize.
37 unsafe {
38 let global = &mut ctx.get().as_mut().global;
39 match val {
40 Val::I32(x) => *global.as_i32_mut() = x,
41 Val::I64(x) => *global.as_i64_mut() = x,
42 Val::F32(x) => *global.as_f32_bits_mut() = x,
43 Val::F64(x) => *global.as_f64_bits_mut() = x,
44 Val::V128(x) => global.set_u128(x.into()),
45 Val::FuncRef(f) => {
46 *global.as_func_ref_mut() =
47 f.map_or(ptr::null_mut(), |f| f.vm_func_ref(&store).as_ptr());
48 }
49 Val::ExternRef(x) => {
50 let new = match x {
51 None => None,
52 Some(x) => Some(x.try_gc_ref(&store)?.unchecked_copy()),
53 };
54 let new = new.as_ref();
55 global.write_gc_ref(&mut store, new);
56 }
57 Val::AnyRef(a) => {
58 let new = match a {
59 None => None,
60 Some(a) => Some(a.try_gc_ref(&store)?.unchecked_copy()),
61 };
62 let new = new.as_ref();
63 global.write_gc_ref(&mut store, new);
64 }
65 Val::ExnRef(e) => {
66 let new = match e {
67 None => None,
68 Some(e) => Some(e.try_gc_ref(&store)?.unchecked_copy()),
69 };
70 let new = new.as_ref();
71 global.write_gc_ref(&mut store, new);
72 }
73 Val::ContRef(None) => {
74 // Allow null continuation references for trampoline globals - these are just placeholders
75 global.write_gc_ref(&mut store, None);
76 }
77 Val::ContRef(Some(_)) => {
78 // TODO(#10248): Implement non-null trampoline continuation reference handling
79 return Err(crate::format_err!(
80 "non-null continuation references in trampoline globals not yet supported"
81 ));
82 }
83 }
84 }
85
86 let index = store.host_globals_mut().push(ctx)?;
87 Ok(crate::Global::from_host(store.id(), index))
88 }
89