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Merged
vados-cosmonic merged 4 commits into from
May 29, 2026
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fix(bindgen): issue with lifting resources #1572

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997086b
fix(bindgen): resource transfer logic
vados-cosmonic May 29, 2026
0ee5fd9
refactor(bindgen): make handle tables global screaming snake case
vados-cosmonic May 29, 2026
59f605d
fix(bindgen): track resource origination at runtime
vados-cosmonic May 29, 2026
7b48a80
refactor(bindgen): clearer autovivicaion of individual handle table
vados-cosmonic May 29, 2026
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23 changes: 11 additions & 12 deletions crates/js-component-bindgen/src/intrinsics/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -92,7 +92,6 @@ pub enum Intrinsic {
SymbolAsyncIterator,
SymbolIterator,
ScopeId,
DefinedResourceTables,
HandleTables,

/// Class that conforms to a `ReadableStreams`-like interface and is usable externally
Expand Down Expand Up @@ -293,8 +292,6 @@ impl Intrinsic {
",
),

Intrinsic::DefinedResourceTables => {}

Intrinsic::FinalizationRegistryCreate => output.push_str(
"
function finalizationRegistryCreate (unregister) {
Expand Down Expand Up @@ -358,11 +355,15 @@ impl Intrinsic {

Intrinsic::WebIdl(w) => w.render(output),

Intrinsic::HandleTables => output.push_str(
"
const handleTables = [];
",
),
Intrinsic::HandleTables => {
let var_name = self.name();
uwriteln!(
output,
r#"
const {var_name} = [];
"#,
);
}

Intrinsic::HasOwnProperty => output.push_str(
"
Expand Down Expand Up @@ -1636,11 +1637,10 @@ impl Intrinsic {
"base64Compile",
"clampGuest",
"ComponentError",
"definedResourceTables",
"fetchCompile",
"finalizationRegistryCreate",
"getErrorPayload",
"handleTables",
"HANDLE_TABLES",
"hasOwnProperty",
"imports",
"instantiateCore",
Expand Down Expand Up @@ -1702,12 +1702,11 @@ impl Intrinsic {
Intrinsic::Base64Compile => "base64Compile",
Intrinsic::ClampGuest => "clampGuest",
Intrinsic::ComponentError => "ComponentError",
Intrinsic::DefinedResourceTables => "definedResourceTables",
Intrinsic::FetchCompile => "fetchCompile",
Intrinsic::FinalizationRegistryCreate => "finalizationRegistryCreate",
Intrinsic::GetErrorPayload => "getErrorPayload",
Intrinsic::GetErrorPayloadString => "getErrorPayloadString",
Intrinsic::HandleTables => "handleTables",
Intrinsic::HandleTables => "HANDLE_TABLES",
Intrinsic::HasOwnProperty => "hasOwnProperty",
Intrinsic::InstantiateCore => "instantiateCore",
Intrinsic::IsLE => "isLE",
Expand Down
104 changes: 72 additions & 32 deletions crates/js-component-bindgen/src/intrinsics/resource.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,7 +1,10 @@
//! Intrinsics that represent helpers that deal with Component Model resources

use std::fmt::Write;

use crate::intrinsics::{Intrinsic, RenderIntrinsicsArgs};
use crate::source::Source;
use crate::uwriteln;

/// This enum contains intrinsics for supporting Component Model resources
#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
Expand Down Expand Up @@ -118,28 +121,32 @@ impl ResourceIntrinsic {
",
),

Self::ResourceTableCreateBorrow => output.push_str(
r#"
function rscTableCreateBorrow(table, rep, scopeId) {
if (scopeId === undefined) {{ throw new Error("missing scopeId"); }}
const free = table[0] & ~T_FLAG;
if (free === 0) {
table.push(scopeId);
table.push(rep);
return (table.length >> 1) - 1;
}
table[0] = table[free];
table[free << 1] = scopeId;
table[(free << 1) + 1] = rep;
return free;
}
"#,
),
Self::ResourceTableCreateBorrow => {
uwriteln!(
output,
r#"
function rscTableCreateBorrow(table, rep, scopeId) {{
if (scopeId === undefined) {{ throw new Error("missing scopeId"); }}
const free = table[0] & ~T_FLAG;
if (free === 0) {{
table.push(scopeId);
table.push(rep);
return (table.length >> 1) - 1;
}}
table[0] = table[free << 1];
table[free << 1] = scopeId;
table[(free << 1) + 1] = rep;
return free;
}}
"#,
);
}

Self::ResourceTableCreateOwn => output.push_str(
"
function rscTableCreateOwn(table, rep) {
const free = table[0] & ~T_FLAG;
table._createdReps.add(rep);
if (free === 0) {
table.push(0);
table.push(rep | T_FLAG);
Expand Down Expand Up @@ -196,56 +203,89 @@ impl ResourceIntrinsic {
),

Self::ResourceTransferBorrow => {
let resource_transfer_borrow_fn = self.name();
let handle_tables = Intrinsic::HandleTables.name();
let resource_borrows = Self::ResourceCallBorrows.name();
let rsc_table_remove = Self::ResourceTableRemove.name();
let rsc_table_create_borrow = Self::ResourceTableCreateBorrow.name();
let defined_resource_tables = Intrinsic::DefinedResourceTables.name();
let scope_id = Intrinsic::ScopeId.name();
output.push_str(&format!("
function resourceTransferBorrow(handle, fromTid, toTid) {{

uwriteln!(
output,
r#"
function {resource_transfer_borrow_fn}(handle, fromTid, toTid) {{
const fromTable = {handle_tables}[fromTid];
const fromHandle = fromTable[(handle << 1) + 1];
const isOwn = (fromHandle & T_FLAG) !== 0;
const rep = isOwn ? fromHandle & ~T_FLAG : {rsc_table_remove}(fromTable, fromHandle).rep;
if ({defined_resource_tables}[toTid]) return rep;
const toTable = {handle_tables}[toTid] || ({handle_tables}[toTid] = [T_FLAG, 0]);

let toTable = {handle_tables}[toTid];
if (!toTable) {{
{handle_tables}[toTid] = [T_FLAG, 0];
toTable = {handle_tables}[toTid];
toTable._createdReps = new Set();
}}

if (toTable._createdReps.has(rep)) {{
return rep;
}}

const newHandle = {rsc_table_create_borrow}(toTable, rep, {scope_id});
{resource_borrows}.push({{ rid: toTid, handle: newHandle }});
return newHandle;
}}
"));
"#
);
}

Self::ResourceTransferBorrowValidLifting => {
let handle_tables = Intrinsic::HandleTables.name();
let rsc_table_remove = Self::ResourceTableRemove.name();
let rsc_table_create_borrow = Self::ResourceTableCreateBorrow.name();
let defined_resource_tables = Intrinsic::DefinedResourceTables.name();
let scope_id = Intrinsic::ScopeId.name();
output.push_str(&format!("
output.push_str(&format!(r#"
function resourceTransferBorrowValidLifting(handle, fromTid, toTid) {{
const fromTable = {handle_tables}[fromTid];
const isOwn = (fromTable[(handle << 1) + 1] & T_FLAG) !== 0;
const rep = isOwn ? fromTable[(handle << 1) + 1] & ~T_FLAG : {rsc_table_remove}(fromTable, handle).rep;
if ({defined_resource_tables}[toTid]) return rep;
const toTable = {handle_tables}[toTid] || ({handle_tables}[toTid] = [T_FLAG, 0]);

let toTable = {handle_tables}[toTid];
if (!toTable) {{
{handle_tables}[toTid] = [T_FLAG, 0];
toTable = {handle_tables}[toTid];
toTable._createdReps = new Set();
}}

if (toTable._createdReps.has(rep)) {{
return rep;
}}

return {rsc_table_create_borrow}(toTable, rep, {scope_id});
}}
"));
"#));
}

Self::ResourceTransferOwn => {
let handle_tables = Intrinsic::HandleTables.name();
let rsc_table_remove = Self::ResourceTableRemove.name();
let rsc_table_create_own = Self::ResourceTableCreateOwn.name();
output.push_str(&format!("
output.push_str(&format!(
r#"
function resourceTransferOwn(handle, fromTid, toTid) {{
const {{ rep }} = {rsc_table_remove}({handle_tables}[fromTid], handle);
const toTable = {handle_tables}[toTid] || ({handle_tables}[toTid] = [T_FLAG, 0]);
return {rsc_table_create_own}(toTable, rep);

let toTable = {handle_tables}[toTid];
if (!toTable) {{
{handle_tables}[toTid] = [T_FLAG, 0];
toTable = {handle_tables}[toTid];
toTable._createdReps = new Set();
}}

const newHandle = {rsc_table_create_own}(toTable, rep);
return newHandle;
}}
"));
"#
));
}

Self::ResourceCallBorrows => {
Expand Down
75 changes: 38 additions & 37 deletions crates/js-component-bindgen/src/transpile_bindgen.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -323,17 +323,15 @@ pub fn transpile_bindgen(
instantiator.initialize();
instantiator.instantiate();

let mut intrinsic_definitions = source::Source::default();

instantiator.resource_definitions(&mut intrinsic_definitions);
instantiator.resource_definitions();
instantiator.instance_flags();

instantiator.bindgen.src.js(&instantiator.src.js);
instantiator.bindgen.src.js_init(&instantiator.src.js_init);

instantiator
.bindgen
.finish_component(name, files, &opts, intrinsic_definitions);
.finish_component(name, files, &opts, source::Source::default());

let exports = instantiator
.bindgen
Expand Down Expand Up @@ -956,7 +954,7 @@ impl<'a> Instantiator<'a, '_> {
}
}

fn resource_definitions(&mut self, definitions: &mut source::Source) {
fn resource_definitions(&mut self) {
// It is theoretically possible for locally defined resources used in no functions
// to still be exported
for resource in 0..self.component.num_resources {
Expand All @@ -970,30 +968,21 @@ impl<'a> Instantiator<'a, '_> {
}
}

// Write out the defined resource table indices for the runtime
if self.bindgen.all_intrinsics.contains(&Intrinsic::Resource(
ResourceIntrinsic::ResourceTransferBorrow,
)) || self.bindgen.all_intrinsics.contains(&Intrinsic::Resource(
ResourceIntrinsic::ResourceTransferBorrowValidLifting,
)) {
let defined_resource_tables = Intrinsic::DefinedResourceTables.name();
uwrite!(definitions, "const {defined_resource_tables} = [");
// Table per-resource
for tidx in 0..self.component.num_resources {
let tid = TypeResourceTableIndex::from_u32(tidx);
let resource_table_ty = &self.types[tid];
let rid = resource_table_ty.unwrap_concrete_ty();
if let Some(defined_index) = self.component.defined_resource_index(rid) {
let instance_idx = resource_table_ty.unwrap_concrete_instance();
if instance_idx == self.component.defined_resource_instances[defined_index] {
uwrite!(definitions, "true,");
}
} else {
uwrite!(definitions, ",");
};
}
uwrite!(definitions, "];\n");
}
// TODO(feat): In the past, we could eagerly build a mapping of resources defined to the tables they correspond to
// to make runtime checks of which table a resource must have been created into first (i.e. the component that implements
// creation of a given resource) a particular resource faster.
//
// This logic was based on component.num_resources and was broken for composed components --
// wasmtime-environ reported a smaller number of resources, and the check was geared towards a *single* component,
// not tying a particular component to a particular table (it is possible for *sub components* to originate different
// resources).
//
// In theory, it should be posible to build this knowledge statically rather than at resource creation,
// so in the future we should attempt to rebulid that code, if possible.
//
// Note that at runtime wasmtime maintains this information and looks it up during a transfer operation, see:
// - https://github.com/bytecodealliance/wasmtime/blob/5f3b67ea055857020bd1ac1f2c3f7fa2e6c31ec0/crates/wasmtime/src/runtime/component/instance.rs#L424
// - https://github.com/bytecodealliance/wasmtime/blob/9c49989a2e71382fd8639288088472f150f2f534/crates/wasmtime/src/runtime/vm/component.rs#L847
}

/// Ensure a component-local `error-context` table has been created
Expand Down Expand Up @@ -1078,34 +1067,46 @@ impl<'a> Instantiator<'a, '_> {
.bindgen
.intrinsic(Intrinsic::Resource(ResourceIntrinsic::ResourceTableRemove));

// Create the relevant handle table
let rtid = resource_table_idx.as_u32();
if is_imported {
// imported
uwriteln!(
self.src.js,
"const handleTable{rtid} = [{rsc_table_flag}, 0];",
r#"
const handleTable{rtid} = [{rsc_table_flag}, 0];
handleTable{rtid}._createdReps = new Set();
"#,
);
if !self.resources_initialized.contains_key(&resource_idx) {
let ridx = resource_idx.as_u32();
uwriteln!(
self.src.js,
"const captureTable{ridx} = new Map();
let captureCnt{ridx} = 0;"
r#"
const captureTable{ridx} = new Map();
let captureCnt{ridx} = 0;
"#
);
self.resources_initialized.insert(resource_idx, true);
}
} else {
// non imported
let finalization_registry_create = self
.bindgen
.intrinsic(Intrinsic::FinalizationRegistryCreate);
uwriteln!(
self.src.js,
"const handleTable{rtid} = [{rsc_table_flag}, 0];
const finalizationRegistry{rtid} = {finalization_registry_create}((handle) => {{
const {{ rep }} = {rsc_table_remove}(handleTable{rtid}, handle);{maybe_dtor}
}});
",
r#"
const handleTable{rtid} = [{rsc_table_flag}, 0];
handleTable{rtid}._createdReps = new Set();
const finalizationRegistry{rtid} = {finalization_registry_create}((handle) => {{
const {{ rep }} = {rsc_table_remove}(handleTable{rtid}, handle);{maybe_dtor}
}});
"#,
);
}

// Add the handle table to the global list
uwriteln!(self.src.js, "{handle_tables}[{rtid}] = handleTable{rtid};");
self.resource_tables_initialized
.insert(resource_table_idx, true);
Expand Down
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