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Merged
avrabe merged 2 commits into from
Mar 16, 2026
Merged

refactor: add ResourceBorrowTransfer and callee_defines_resource flag #33

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0940db6
refactor: add ResourceBorrowTransfer and callee_defines_resource flag
avrabe Mar 16, 2026
b953f7f
fix: add type alias for ResourceImportMap to satisfy clippy type_comp…
avrabe Mar 16, 2026
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171 changes: 119 additions & 52 deletions meld-core/src/adapter/fact.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -42,23 +42,39 @@ fn alignment_for_encoding(encoding: StringEncoding) -> i32 {

/// Build a lookup from `(module, field)` → merged function index for resource imports.
///
/// Scans the merged module's imports to find `[resource-rep]` function imports
/// and records their merged function indices.
fn build_resource_import_map(
merged: &MergedModule,
) -> std::collections::HashMap<(String, String), u32> {
/// Scans the merged module's imports to find `[resource-rep]` and `[resource-new]`
/// function imports and records their merged function indices.
type ResourceImportMap = std::collections::HashMap<(String, String), u32>;

fn build_resource_import_maps(merged: &MergedModule) -> (ResourceImportMap, ResourceImportMap) {
use wasm_encoder::EntityType;
let mut map = std::collections::HashMap::new();
let mut rep_map = std::collections::HashMap::new();
let mut new_map = std::collections::HashMap::new();
let mut func_idx = 0u32;
for imp in &merged.imports {
if matches!(imp.entity_type, EntityType::Function(_)) {
if imp.name.starts_with("[resource-rep]") {
map.insert((imp.module.clone(), imp.name.clone()), func_idx);
rep_map.insert((imp.module.clone(), imp.name.clone()), func_idx);
} else if imp.name.starts_with("[resource-new]") {
new_map.insert((imp.module.clone(), imp.name.clone()), func_idx);
}
func_idx += 1;
}
}
map
(rep_map, new_map)
}

/// Emit Phase 0: convert borrow resource handles for each `ResourceBorrowTransfer`.
fn emit_resource_borrow_phase0(func: &mut Function, transfers: &[super::ResourceBorrowTransfer]) {
for t in transfers {
func.instruction(&Instruction::LocalGet(t.param_idx));
func.instruction(&Instruction::Call(t.rep_func));
if let Some(new_func) = t.new_func {
// 3-component chain: rep → new handle in callee's table
func.instruction(&Instruction::Call(new_func));
}
func.instruction(&Instruction::LocalSet(t.param_idx));
}
}

/// FACT-style adapter generator
Expand All @@ -79,15 +95,17 @@ impl FactStyleGenerator {
site: &AdapterSite,
merged: &MergedModule,
_adapter_idx: usize,
resource_imports: &std::collections::HashMap<(String, String), u32>,
resource_rep_imports: &std::collections::HashMap<(String, String), u32>,
resource_new_imports: &std::collections::HashMap<(String, String), u32>,
) -> Result<AdapterFunction> {
let name = format!(
"$adapter_{}_{}_to_{}_{}",
site.from_component, site.from_module, site.to_component, site.to_module
);

// Determine adapter options based on call site
let options = self.analyze_call_site(site, merged, resource_imports);
let options =
self.analyze_call_site(site, merged, resource_rep_imports, resource_new_imports);

// Generate the adapter function body
let (type_idx, body) = if site.crosses_memory && options.needs_transcoding() {
Expand Down Expand Up @@ -115,7 +133,8 @@ impl FactStyleGenerator {
&self,
site: &AdapterSite,
merged: &MergedModule,
resource_imports: &std::collections::HashMap<(String, String), u32>,
resource_rep_imports: &std::collections::HashMap<(String, String), u32>,
resource_new_imports: &std::collections::HashMap<(String, String), u32>,
) -> AdapterOptions {
let mut options = AdapterOptions::default();

Expand Down Expand Up @@ -201,20 +220,82 @@ impl FactStyleGenerator {
//
// Results are never converted — own results have resource.new called
// by the callee's core function, and borrows cannot appear in results.
// Build caller resource params index by flat_idx for quick lookup
let caller_ops: std::collections::HashMap<u32, &crate::resolver::ResolvedResourceOp> = site
.requirements
.caller_resource_params
.iter()
.map(|op| (op.flat_idx, op))
.collect();

for op in &site.requirements.resource_params {
if op.is_owned {
continue; // own<T>: callee handles conversion internally
}
if let Some(&func_idx) =
resource_imports.get(&(op.import_module.clone(), op.import_field.clone()))
{
options.resource_rep_calls.push((op.flat_idx, func_idx));

if op.callee_defines_resource {
// 2-component case: callee defines the resource.
// Use callee's [resource-rep] which returns rep directly.
if let Some(&rep_func) =
resource_rep_imports.get(&(op.import_module.clone(), op.import_field.clone()))
{
options
.resource_rep_calls
.push(super::ResourceBorrowTransfer {
param_idx: op.flat_idx,
rep_func,
new_func: None,
});
}
} else {
log::debug!(
"Resource rep import not found: ({}, {})",
op.import_module,
op.import_field
);
// 3-component case: callee doesn't define the resource.
// Use caller's [resource-rep] to convert handle → rep,
// then callee's [resource-new] to create handle in callee's table.
//
// Find the caller's [resource-rep] by matching the resource name
// from the callee's import field (e.g., "float" from "[resource-rep]float").
let resource_name = op
.import_field
.strip_prefix("[resource-rep]")
.unwrap_or(&op.import_field);

// Look for a [resource-rep]<name> import from a DIFFERENT module than callee's
let caller_rep = resource_rep_imports
.iter()
.find(|((module, field), _)| {
field.ends_with(resource_name)
&& field.starts_with("[resource-rep]")
&& *module != op.import_module
})
.or_else(|| {
// Fallback: try caller_resource_params if available
caller_ops.get(&op.flat_idx).and_then(|caller_op| {
resource_rep_imports.get_key_value(&(
caller_op.import_module.clone(),
caller_op.import_field.clone(),
))
})
});

if let Some((_, &rep_func)) = caller_rep {
let new_field = op.import_field.replace("[resource-rep]", "[resource-new]");
let new_func = resource_new_imports
.get(&(op.import_module.clone(), new_field))
.copied();
options
.resource_rep_calls
.push(super::ResourceBorrowTransfer {
param_idx: op.flat_idx,
rep_func,
new_func,
});
} else {
log::debug!(
"No caller resource rep found for {} at flat_idx {}",
resource_name,
op.flat_idx
);
}
}
}

Expand Down Expand Up @@ -253,12 +334,8 @@ impl FactStyleGenerator {
}
let mut func = Function::new(locals);

// Phase 0: Convert borrow resource handles → representations
for &(param_idx, rep_func) in &options.resource_rep_calls {
func.instruction(&Instruction::LocalGet(param_idx));
func.instruction(&Instruction::Call(rep_func));
func.instruction(&Instruction::LocalSet(param_idx));
}
// Phase 0: Convert borrow resource handles
emit_resource_borrow_phase0(&mut func, &options.resource_rep_calls);

for i in 0..param_count {
func.instruction(&Instruction::LocalGet(i as u32));
Expand Down Expand Up @@ -398,12 +475,8 @@ impl FactStyleGenerator {
}
let mut func = Function::new(locals);

// Phase 0: Convert borrow resource handles → representations
for &(param_idx, rep_func) in &options.resource_rep_calls {
func.instruction(&Instruction::LocalGet(param_idx));
func.instruction(&Instruction::Call(rep_func));
func.instruction(&Instruction::LocalSet(param_idx));
}
// Phase 0: Convert borrow resource handles
emit_resource_borrow_phase0(&mut func, &options.resource_rep_calls);

for i in 0..param_count {
func.instruction(&Instruction::LocalGet(i as u32));
Expand Down Expand Up @@ -517,12 +590,8 @@ impl FactStyleGenerator {

let mut func = Function::new(local_decls);

// Phase 0: Convert borrow resource handles → representations
for &(param_idx, rep_func) in &options.resource_rep_calls {
func.instruction(&Instruction::LocalGet(param_idx));
func.instruction(&Instruction::Call(rep_func));
func.instruction(&Instruction::LocalSet(param_idx));
}
// Phase 0: Convert borrow resource handles
emit_resource_borrow_phase0(&mut func, &options.resource_rep_calls);

// Assign scratch local indices (after params)
let base = param_count as u32;
Expand Down Expand Up @@ -895,12 +964,8 @@ impl FactStyleGenerator {
let local_decls = vec![(scratch_count, wasm_encoder::ValType::I32)];
let mut func = Function::new(local_decls);

// Phase 0: Convert borrow resource handles → representations
for &(param_idx, rep_func) in &options.resource_rep_calls {
func.instruction(&Instruction::LocalGet(param_idx));
func.instruction(&Instruction::Call(rep_func));
func.instruction(&Instruction::LocalSet(param_idx));
}
// Phase 0: Convert borrow resource handles
emit_resource_borrow_phase0(&mut func, &options.resource_rep_calls);

// --- Phase 1: Outbound copy of ALL pointer pairs (caller → callee) ---
if let Some(callee_realloc) = options
Expand Down Expand Up @@ -1551,12 +1616,8 @@ impl FactStyleGenerator {
}
let mut func = Function::new(local_decls);

// Phase 0: Convert borrow resource handles → representations
for &(param_idx, rep_func) in &options.resource_rep_calls {
func.instruction(&Instruction::LocalGet(param_idx));
func.instruction(&Instruction::Call(rep_func));
func.instruction(&Instruction::LocalSet(param_idx));
}
// Phase 0: Convert borrow resource handles
emit_resource_borrow_phase0(&mut func, &options.resource_rep_calls);

// Generate transcoding logic based on encoding pair

Expand Down Expand Up @@ -2446,11 +2507,17 @@ impl AdapterGenerator for FactStyleGenerator {
merged: &MergedModule,
graph: &DependencyGraph,
) -> Result<Vec<AdapterFunction>> {
let resource_imports = build_resource_import_map(merged);
let (resource_rep_imports, resource_new_imports) = build_resource_import_maps(merged);
let mut adapters = Vec::new();

for (idx, site) in graph.adapter_sites.iter().enumerate() {
let adapter = self.generate_adapter(site, merged, idx, &resource_imports)?;
let adapter = self.generate_adapter(
site,
merged,
idx,
&resource_rep_imports,
&resource_new_imports,
)?;
adapters.push(adapter);
}

Expand Down
39 changes: 24 additions & 15 deletions meld-core/src/adapter/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -124,24 +124,33 @@ pub struct AdapterOptions {
/// Called after results have been copied back, to allow callee cleanup.
pub callee_post_return: Option<u32>,

/// Resource borrow params needing handle→representation conversion.
/// Each entry: `(flat_param_idx, merged_func_idx of [resource-rep])`.
/// Resource borrow params needing handle conversion.
///
/// Per the canonical ABI spec, `borrow<T>` params where T is defined by
/// the callee receive the **representation** (raw pointer), not the handle.
/// The `lower_borrow` function has `if cx.inst is t.rt.impl: return rep`.
/// So the adapter must call `[resource-rep]R(handle)` to convert before
/// forwarding to the callee's core function.
/// Per the canonical ABI, `borrow<T>` params need different handling
/// depending on who defines the resource:
///
/// `own<T>` params always receive a **handle** (table index) because
/// `lower_own` unconditionally creates a handle entry. The callee's core
/// function calls `from_handle` / `[resource-rep]` internally, so the
/// adapter must NOT convert own params.
/// - **Callee defines T**: adapter calls `[resource-rep](handle) → rep`
/// and passes rep to callee (which expects raw pointer via identity lift).
///
/// Results are never converted by the adapter — the callee's core function
/// already calls `[resource-new]R` internally for own results, and borrows
/// cannot appear in results.
pub resource_rep_calls: Vec<(u32, u32)>,
/// - **Neither defines T** (3-component chain): adapter calls caller's
/// `[resource-rep](handle) → rep`, then callee's `[resource-new](rep) → new_handle`,
/// and passes new_handle to callee (which expects a handle in its own table).
///
/// `own<T>` params are never converted (callee calls from_handle internally).
pub resource_rep_calls: Vec<ResourceBorrowTransfer>,
}

/// Describes how to transfer a `borrow<T>` handle across an adapter boundary.
#[derive(Debug, Clone)]
pub struct ResourceBorrowTransfer {
/// The flat parameter index holding the handle
pub param_idx: u32,
/// Merged function index of `[resource-rep]` to convert handle → rep
pub rep_func: u32,
/// If the callee doesn't define the resource, the merged function index
/// of `[resource-new]` to convert rep → new handle in callee's table.
/// None when the callee defines the resource (rep is passed directly).
pub new_func: Option<u32>,
}

impl Default for AdapterOptions {
Expand Down
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