lab/sx
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

refactor(B8.3): move lambdas + captures to lower/closure.zig

Browse Source 
Verbatim relocation of the 5-method closure cluster (lowerLambda,
bare-fn trampoline, closure-to-bare-fn adapter, capture collection, env
sizing) into src/ir/lower/closure.zig. 5 aliases on Lowering keep all
call sites unchanged. Method pub-flip: typeAlignBytes.

Resolves the B7.1 flag: CaptureInfo relocates from lower/call.zig to
lower/closure.zig (its domain home, next to collectCaptures); the
Lowering type alias is repointed so external references are unchanged.

Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
This commit is contained in:
agra
2026-06-10 14:43:04 +03:00
parent 35e35adb0a
commit 89b3789973
3 changed files with 743 additions and 688 deletions
Download Patch File Download Diff File Expand all files Collapse all files

690
src/ir/lower.zig
View File

@@ -47,6 +47,7 @@ const lower_call = @import("lower/call.zig");
const lower_pack = @import("lower/pack.zig");
const lower_generic = @import("lower/generic.zig");
const lower_expr = @import("lower/expr.zig");
const lower_closure = @import("lower/closure.zig");
const TypeId = types.TypeId;
const StringId = types.StringId;
@@ -501,690 +502,12 @@ pub const Lowering = struct {
// ── Public entry point ──────────────────────────────────────────
pub fn lowerLambda(self: *Lowering, lam: *const ast.Lambda) Ref {
// Lower the lambda body as a new anonymous function
var buf: [64]u8 = undefined;
const name = std.fmt.bufPrint(&buf, "__lambda_{d}", .{self.block_counter}) catch "__lambda";
self.block_counter += 1;
// Collect lambda param names for exclusion from captures
var param_names = std.StringHashMap(void).init(self.alloc);
defer param_names.deinit();
for (lam.params) |p| {
param_names.put(p.name, {}) catch {};
}
// Pre-scan lambda body AST for free variables (captures)
var captures = std.ArrayList(CaptureInfo).empty;
defer captures.deinit(self.alloc);
self.collectCaptures(lam.body, &param_names, &captures);
// Deduplicate captures
var seen = std.StringHashMap(void).init(self.alloc);
defer seen.deinit();
var deduped = std.ArrayList(CaptureInfo).empty;
defer deduped.deinit(self.alloc);
for (captures.items) |cap| {
if (!seen.contains(cap.name)) {
seen.put(cap.name, {}) catch {};
deduped.append(self.alloc, cap) catch {};
}
}
const capture_list = deduped.items;
// Build env struct type if there are captures
var env_struct_ty: TypeId = .void;
if (capture_list.len > 0) {
const env_field_data = self.alloc.alloc(types.TypeInfo.StructInfo.Field, capture_list.len) catch unreachable;
for (capture_list, 0..) |cap, i| {
var nbuf: [32]u8 = undefined;
const fname = std.fmt.bufPrint(&nbuf, "cap_{d}", .{i}) catch "cap";
env_field_data[i] = .{
.name = self.module.types.internString(fname),
.ty = cap.ty,
};
}
const env_name = std.fmt.bufPrint(&buf, "__env_{d}", .{self.block_counter}) catch "__env";
const env_name_id = self.module.types.internString(env_name);
env_struct_ty = self.module.types.intern(.{ .@"struct" = .{
.name = env_name_id,
.fields = env_field_data,
} });
}
// Save current builder state
const saved_func = self.builder.func;
const saved_block = self.builder.current_block;
const saved_counter = self.builder.inst_counter;
const saved_scope = self.scope;
// Build param list. Convention when implicit_ctx is enabled:
// slot 0 = __sx_ctx: *void
// slot 1 = env: *void
// slot 2+ = user params
// Without implicit_ctx, env is slot 0 and user params follow.
var params = std.ArrayList(Function.Param).empty;
const env_ptr_ty = self.module.types.ptrTo(.void);
const lambda_wants_ctx = self.implicit_ctx_enabled and lam.call_conv != .c;
if (lambda_wants_ctx) {
params.append(self.alloc, .{
.name = self.module.types.internString("__sx_ctx"),
.ty = env_ptr_ty,
}) catch unreachable;
}
params.append(self.alloc, .{
.name = self.module.types.internString("env"),
.ty = env_ptr_ty,
}) catch unreachable;
// Get target closure param types for inference (from Closure(T1, T2) -> R annotations)
const target_closure_params: ?[]const TypeId = if (self.target_type) |tt| blk: {
if (!tt.isBuiltin()) {
const tti = self.module.types.get(tt);
if (tti == .closure) break :blk tti.closure.params;
// Unwrap ?Closure(...) → Closure(...)
if (tti == .optional) {
const inner = tti.optional.child;
if (!inner.isBuiltin()) {
const inner_info = self.module.types.get(inner);
if (inner_info == .closure) break :blk inner_info.closure.params;
}
}
}
break :blk null;
} else null;
// User params follow the ctx (optional) + env slots in `params`.
const user_param_base: usize = (if (lambda_wants_ctx) @as(usize, 1) else 0) + 1;
for (lam.params, 0..) |p, pi| {
const pty: TypeId = blk: {
// Unannotated lambda params take their type positionally from
// the target `Closure(T0, …)` signature. Resolve them here so
// `resolveParamType` (which would diagnose a missing annotation)
// is only called for params that carry one.
if (p.type_expr.data == .inferred_type) {
if (target_closure_params != null and pi < target_closure_params.?.len) {
break :blk target_closure_params.?[pi];
}
if (self.diagnostics) |d| {
d.addFmt(.err, p.type_expr.span, "cannot infer type of lambda parameter '{s}'; annotate it or use the lambda where a closure type is expected", .{p.name});
}
break :blk .unresolved;
}
break :blk self.resolveParamType(&p);
};
params.append(self.alloc, .{
.name = self.module.types.internString(p.name),
.ty = pty,
}) catch unreachable;
}
const ret_ty = blk: {
if (lam.return_type) |rt| {
break :blk type_bridge.resolveAstType(rt, &self.module.types, &self.program_index.type_alias_map, &self.program_index.module_const_map);
}
// Use target closure return type if available — but only when it's
// a resolved type. An `.unresolved` ret comes from an unbound
// generic (`Closure(..) -> $R`); fall through to infer it from the
// body so the concrete return drives `$R` inference at the call site.
if (self.target_type) |tt| {
if (!tt.isBuiltin()) {
const tti = self.module.types.get(tt);
if (tti == .closure and tti.closure.ret != .unresolved) break :blk tti.closure.ret;
// Unwrap ?Closure(...) → Closure(...)
if (tti == .optional) {
const inner = tti.optional.child;
if (!inner.isBuiltin()) {
const inner_info = self.module.types.get(inner);
if (inner_info == .closure and inner_info.closure.ret != .unresolved) break :blk inner_info.closure.ret;
}
}
}
}
// Arrow lambda without explicit return type — infer from body expression
// Temporarily bind params in scope so inferExprType can resolve param types
var temp_scope = Scope.init(self.alloc, self.scope);
const saved = self.scope;
self.scope = &temp_scope;
for (lam.params, 0..) |p, i| {
const pty = params.items[user_param_base + i].ty;
temp_scope.put(p.name, .{ .ref = @enumFromInt(0), .ty = pty, .is_alloca = false });
}
const inferred = self.inferExprType(lam.body);
self.scope = saved;
temp_scope.deinit();
break :blk inferred;
};
const name_id = self.module.types.internString(name);
const func_id = self.builder.beginFunction(name_id, params.items, ret_ty);
if (lam.call_conv == .c) {
self.module.getFunctionMut(func_id).call_conv = .c;
}
self.builder.currentFunc().has_implicit_ctx = lambda_wants_ctx;
// Param-slot layout: ctx at 0 (if present), env at ctx_slots,
// user args at ctx_slots+1.
const lambda_ctx_slots: u32 = if (lambda_wants_ctx) 1 else 0;
const env_param_idx: u32 = lambda_ctx_slots;
const user_param_base_lam: u32 = lambda_ctx_slots + 1;
// Save + rebind current_ctx_ref so the body's sx-to-sx calls
// forward the trampoline's own ctx (slot 0).
const saved_ctx_ref_lam = self.current_ctx_ref;
defer self.current_ctx_ref = saved_ctx_ref_lam;
if (lambda_wants_ctx) self.current_ctx_ref = Ref.fromIndex(0);
// A lambda is its own function: its `return` must drain only ITS OWN
// `defer`s, not the enclosing function's. Open a fresh defer window
// (like `lowerFunction`/`monomorphizeFunction`) and restore on exit —
// otherwise lowering a closure literal inside a `defer` body re-enters
// the enclosing function's defer drain (infinite recursion — issue 0073).
const saved_func_defer_base = self.func_defer_base;
const saved_defer_len = self.defer_stack.items.len;
defer {
self.func_defer_base = saved_func_defer_base;
self.defer_stack.shrinkRetainingCapacity(saved_defer_len);
}
self.func_defer_base = saved_defer_len;
// Create entry block
const entry_name = self.module.types.internString("entry");
const entry = self.builder.appendBlock(entry_name, &.{});
self.builder.switchToBlock(entry);
// Create scope WITHOUT parent — captures are bound from env, not parent scope
var lambda_scope = Scope.init(self.alloc, null);
self.scope = &lambda_scope;
// Bind captures from env struct (at env_param_idx)
if (capture_list.len > 0) {
const env_param_ref = Ref.fromIndex(env_param_idx);
// Alloca env struct locally so struct_gep can resolve the type
const env_local = self.builder.alloca(env_struct_ty);
// Compute env size
const env_byte_size_inner = self.computeEnvSize(capture_list);
const env_size_val = self.builder.constInt(@intCast(env_byte_size_inner), .s64);
// memcpy(local_alloca, env_param, size)
_ = self.callForeign("memcpy", &.{ env_local, env_param_ref, env_size_val }, self.module.types.ptrTo(.void));
for (capture_list, 0..) |cap, i| {
// GEP into env struct to get field pointer
const field_ptr = self.builder.structGepTyped(env_local, @intCast(i), self.module.types.ptrTo(cap.ty), env_struct_ty);
// Load the captured value into a local alloca
const loaded = self.builder.load(field_ptr, cap.ty);
const slot = self.builder.alloca(cap.ty);
self.builder.store(slot, loaded);
lambda_scope.put(cap.name, .{ .ref = slot, .ty = cap.ty, .is_alloca = true });
}
}
// Also need parent scope for function lookups (but not variable lookups)
// Set up fn_names from parent scope chain
{
var s: ?*Scope = saved_scope;
while (s) |scope| {
var it = scope.fn_names.iterator();
while (it.next()) |e| {
if (!lambda_scope.fn_names.contains(e.key_ptr.*)) {
lambda_scope.fn_names.put(e.key_ptr.*, e.value_ptr.*) catch {};
}
}
s = scope.parent;
}
}
// Bind params (user args start at user_param_base_lam, shifted past ctx + env).
// Use the signature types computed above (`params`), which already
// applied contextual typing from the target closure to untyped params —
// `resolveParamType` alone would drop it and default each to s64.
for (lam.params, 0..) |p, i| {
const pty = params.items[user_param_base + i].ty;
const slot = self.builder.alloca(pty);
const param_ref = Ref.fromIndex(user_param_base_lam + @as(u32, @intCast(i)));
self.builder.store(slot, param_ref);
lambda_scope.put(p.name, .{ .ref = slot, .ty = pty, .is_alloca = true });
}
// Lower body — capture last expression as return value. The
// `in_lambda_body` flag scopes the lambda-specific `raise`-not-failable
// hint; save/restore so a lambda nested inside a regular function (or a
// lambda inside a lambda) restores the enclosing context.
const saved_in_lambda = self.in_lambda_body;
self.in_lambda_body = true;
if (ret_ty != .void) {
if (self.lowerBlockValue(lam.body)) |val| {
if (!self.currentBlockHasTerminator()) {
const val_ty = self.builder.getRefType(val);
// A value-carrying failable arrow lambda (`-> (T, !) => expr`)
// yields the bare success value; the compiler appends the
// no-error slot (0) — same as a `return v` in a block body.
if (!ret_ty.isBuiltin() and self.module.types.get(ret_ty) == .tuple and self.errorChannelOf(ret_ty) != null) {
self.lowerFailableSuccessReturn(val, ret_ty, lam.body.span);
} else {
const coerced = if (val_ty != .void) self.coerceToType(val, val_ty, ret_ty) else val;
self.builder.ret(coerced, ret_ty);
}
}
}
} else {
self.lowerBlock(lam.body);
}
self.in_lambda_body = saved_in_lambda;
self.ensureTerminator(ret_ty);
self.builder.finalize();
// Restore builder state
self.scope = saved_scope;
lambda_scope.deinit();
self.builder.func = saved_func;
self.builder.current_block = saved_block;
self.builder.inst_counter = saved_counter;
// Restore the caller's `current_ctx_ref` BEFORE we emit the env
// alloc/memcpy below — those run in the caller's scope, and
// `allocViaContext` reads `current_ctx_ref` to find the
// installed allocator. Without this, the env_heap dispatch
// would still see `Ref.fromIndex(0)` (the lambda's own ctx
// param), which doesn't exist in the caller's frame and
// silently routes through the default context instead of any
// surrounding `push Context.{ allocator = ... }`.
self.current_ctx_ref = saved_ctx_ref_lam;
// Closure flowing into a BARE function-pointer slot (`(T) -> U`, no env):
// the slot is called without the closure env arg, so the closure fn can't
// be passed directly. For a capture-free closure whose return type matches
// the slot, emit an adapter with the bare ABI. Reject the cases the bare
// ABI can't represent: a capturing closure (env has nowhere to live), and
// a failable closure into a non-failable slot (foreign code can't observe
// the error channel — ERR E5.1 FFI-boundary rule).
if (self.target_type) |tt| {
if (!tt.isBuiltin() and self.module.types.get(tt) == .function) {
const slot_ret = self.module.types.get(tt).function.ret;
const widen_ok = self.errorChannelOf(slot_ret) != null and self.errorChannelOf(ret_ty) == null and self.failableSuccessType(slot_ret) == ret_ty;
if (capture_list.len > 0) {
if (self.diagnostics) |d| d.addFmt(.err, lam.body.span, "a capturing closure cannot be passed as a bare function pointer; declare the parameter type as `Closure(...)` so its environment is carried", .{});
} else if (ret_ty == slot_ret or widen_ok) {
// Matching ABI, or a non-failable closure widening into a
// failable slot (∅ ⊆ slot set) — the adapter wraps {value, 0}.
const adapter = self.createClosureToBareFnAdapter(func_id, self.module.types.get(tt).function, ret_ty, lam.body.span);
return self.builder.emit(.{ .func_ref = adapter }, tt);
} else if (self.errorChannelOf(ret_ty) != null and self.errorChannelOf(slot_ret) == null) {
if (self.diagnostics) |d| d.addFmt(.err, lam.body.span, "failable closure cannot be assigned to a non-failable function-type slot; foreign code can't observe the error channel — handle the error in a wrapper closure that absorbs it", .{});
} else if (self.diagnostics) |d| {
d.addFmt(.err, lam.body.span, "closure return type does not match the function-type slot", .{});
}
}
}
// Create proper closure type (user-visible params only — skip ctx + env).
const skip_count: usize = if (lambda_wants_ctx) 2 else 1;
var param_types_list = std.ArrayList(TypeId).empty;
for (params.items[skip_count..]) |p| {
param_types_list.append(self.alloc, p.ty) catch unreachable;
}
const closure_ty = self.module.types.closureType(param_types_list.items, ret_ty);
// Build env and closure in the caller's scope
if (capture_list.len > 0) {
// Alloca env struct on stack (so struct_gep can resolve the type)
const env_local = self.builder.alloca(env_struct_ty);
// Store captured values into env struct fields
for (capture_list, 0..) |cap, i| {
const gep = self.builder.structGepTyped(env_local, @intCast(i), self.module.types.ptrTo(cap.ty), env_struct_ty);
const val = if (cap.is_alloca)
self.builder.load(cap.ref, cap.ty)
else
cap.ref;
self.builder.store(gep, val);
}
// Copy env to heap (so it outlives the stack frame).
// Route through `context.allocator.alloc` rather than calling
// libc malloc directly so closures respect a surrounding
// `push Context.{ allocator = ... }` and a tracker / arena
// counts the env allocation alongside everything else.
const env_byte_size = self.computeEnvSize(capture_list);
const env_size = self.builder.constInt(@intCast(env_byte_size), .s64);
const ptr_void = self.module.types.ptrTo(.void);
const env_heap = self.allocViaContext(env_size, ptr_void);
// memcpy(heap, stack_alloca, size)
_ = self.callForeign("memcpy", &.{ env_heap, env_local, env_size }, ptr_void);
return self.builder.closureCreate(func_id, env_heap, closure_ty);
} else {
return self.builder.closureCreate(func_id, Ref.none, closure_ty);
}
}
/// Create a trampoline function that wraps a bare function for closure auto-promotion.
/// The trampoline has signature `(env: *void, args...) -> ret` and simply calls the
/// bare function with `(args...)`, ignoring the env parameter.
pub fn createBareFnTrampoline(self: *Lowering, bare_func_id: FuncId, closure_info: types.TypeInfo.ClosureInfo) FuncId {
// Build trampoline params: [__sx_ctx]? + env + closure params.
// When the program uses Context, every sx-side trampoline carries
// the implicit ctx at slot 0 and forwards it to the wrapped
// function (which is also sx-side and expects it at slot 0).
var params = std.ArrayList(inst_mod.Function.Param).empty;
defer params.deinit(self.alloc);
const void_ptr_ty = self.module.types.ptrTo(.void);
const wants_ctx = self.implicit_ctx_enabled;
if (wants_ctx) {
params.append(self.alloc, .{ .name = self.module.types.internString("__sx_ctx"), .ty = void_ptr_ty }) catch unreachable;
}
const env_name = self.module.types.internString("env");
params.append(self.alloc, .{ .name = env_name, .ty = void_ptr_ty }) catch unreachable;
for (closure_info.params, 0..) |pty, i| {
var buf: [32]u8 = undefined;
const pname = std.fmt.bufPrint(&buf, "a{d}", .{i}) catch "arg";
params.append(self.alloc, .{ .name = self.module.types.internString(pname), .ty = pty }) catch unreachable;
}
// Generate unique trampoline name
const bare_func = self.module.functions.items[bare_func_id.index()];
const bare_name = self.module.types.getString(bare_func.name);
var name_buf: [128]u8 = undefined;
const tramp_name = std.fmt.bufPrint(&name_buf, "__tramp_{s}", .{bare_name}) catch "__tramp";
const tramp_name_id = self.module.types.internString(tramp_name);
// Save builder state
const saved_func = self.builder.func;
const saved_block = self.builder.current_block;
const saved_counter = self.builder.inst_counter;
// Create function
const owned_params = self.alloc.dupe(inst_mod.Function.Param, params.items) catch unreachable;
var func = inst_mod.Function.init(tramp_name_id, owned_params, closure_info.ret);
func.has_implicit_ctx = wants_ctx;
const func_id = self.module.addFunction(func);
self.builder.func = func_id;
self.builder.inst_counter = @intCast(owned_params.len); // params occupy refs 0..N-1
const entry_name = self.module.types.internString("entry");
const entry_block = self.builder.appendBlock(entry_name, &.{});
self.builder.switchToBlock(entry_block);
// Build call args: forward [__sx_ctx]? + user_params (skip env).
// Trampoline slots: 0=ctx (if present), {0|1}=env, then user args.
const ctx_slots: usize = if (wants_ctx) 1 else 0;
const user_arg_start: u32 = @intCast(ctx_slots + 1); // skip ctx + env
var call_args = std.ArrayList(Ref).empty;
defer call_args.deinit(self.alloc);
if (wants_ctx and bare_func.has_implicit_ctx) {
call_args.append(self.alloc, Ref.fromIndex(0)) catch unreachable; // forward our ctx
}
for (closure_info.params, 0..) |_, i| {
call_args.append(self.alloc, Ref.fromIndex(user_arg_start + @as(u32, @intCast(i)))) catch unreachable;
}
const owned_args = self.alloc.dupe(Ref, call_args.items) catch unreachable;
const result = self.builder.emit(.{ .call = .{ .callee = bare_func_id, .args = owned_args } }, closure_info.ret);
// Return result (or void)
if (closure_info.ret != .void) {
self.builder.ret(result, closure_info.ret);
} else {
self.builder.retVoid();
}
self.builder.finalize();
// Restore builder state
self.builder.func = saved_func;
self.builder.current_block = saved_block;
self.builder.inst_counter = saved_counter;
return func_id;
}
/// Adapter for coercing a closure into a BARE function-pointer slot
/// (`(T) -> U`, no env). The closure's underlying function has signature
/// `[ctx?] + env + user-params`, but a bare fn-ptr slot is *called* without
/// the env arg — so the closure fn can't be used directly (the env slot
/// would swallow the first user arg). This adapter carries the bare ABI
/// (`[ctx?] + user-params`) and forwards to the closure fn with a null env.
/// Only sound for capture-free closures (a null env is correct iff the body
/// reads no captures); the caller rejects capturing closures.
///
/// When `closure_ret` differs from `fn_info.ret`, this is the ∅-widening
/// case (a non-failable closure into a failable slot): the closure returns
/// the success value and the adapter wraps it into the slot's `{value, 0}`
/// failable tuple (ERR E5.1 non-failable→failable widening).
fn createClosureToBareFnAdapter(self: *Lowering, closure_func_id: FuncId, fn_info: types.TypeInfo.FunctionInfo, closure_ret: TypeId, span: ast.Span) FuncId {
var params = std.ArrayList(inst_mod.Function.Param).empty;
defer params.deinit(self.alloc);
const void_ptr_ty = self.module.types.ptrTo(.void);
const wants_ctx = self.implicit_ctx_enabled;
if (wants_ctx) {
params.append(self.alloc, .{ .name = self.module.types.internString("__sx_ctx"), .ty = void_ptr_ty }) catch unreachable;
}
for (fn_info.params, 0..) |pty, i| {
var buf: [32]u8 = undefined;
const pname = std.fmt.bufPrint(&buf, "a{d}", .{i}) catch "arg";
params.append(self.alloc, .{ .name = self.module.types.internString(pname), .ty = pty }) catch unreachable;
}
const closure_func = self.module.functions.items[closure_func_id.index()];
const closure_name = self.module.types.getString(closure_func.name);
var name_buf: [128]u8 = undefined;
const adapter_name = std.fmt.bufPrint(&name_buf, "__cl2fn_{s}", .{closure_name}) catch "__cl2fn";
const adapter_name_id = self.module.types.internString(adapter_name);
const saved_func = self.builder.func;
const saved_block = self.builder.current_block;
const saved_counter = self.builder.inst_counter;
const owned_params = self.alloc.dupe(inst_mod.Function.Param, params.items) catch unreachable;
var func = inst_mod.Function.init(adapter_name_id, owned_params, fn_info.ret);
func.has_implicit_ctx = wants_ctx;
const func_id = self.module.addFunction(func);
self.builder.func = func_id;
self.builder.inst_counter = @intCast(owned_params.len);
const entry_name = self.module.types.internString("entry");
const entry_block = self.builder.appendBlock(entry_name, &.{});
self.builder.switchToBlock(entry_block);
// Forward [ctx?] + null env + user params to the closure fn.
const ctx_slots: usize = if (wants_ctx) 1 else 0;
var call_args = std.ArrayList(Ref).empty;
defer call_args.deinit(self.alloc);
if (wants_ctx) call_args.append(self.alloc, Ref.fromIndex(0)) catch unreachable;
call_args.append(self.alloc, self.builder.constNull(void_ptr_ty)) catch unreachable;
for (fn_info.params, 0..) |_, i| {
call_args.append(self.alloc, Ref.fromIndex(@intCast(ctx_slots + i))) catch unreachable;
}
const owned_args = self.alloc.dupe(Ref, call_args.items) catch unreachable;
const result = self.builder.emit(.{ .call = .{ .callee = closure_func_id, .args = owned_args } }, closure_ret);
if (closure_ret == fn_info.ret) {
if (fn_info.ret != .void) {
self.builder.ret(result, fn_info.ret);
} else {
self.builder.retVoid();
}
} else {
// ∅-widening: closure returns the success value; wrap `{value, 0}`
// into the slot's failable tuple.
self.lowerFailableSuccessReturn(result, fn_info.ret, span);
}
self.builder.finalize();
self.builder.func = saved_func;
self.builder.current_block = saved_block;
self.builder.inst_counter = saved_counter;
return func_id;
}
/// Walk an AST node and collect free variable references (identifiers that are
/// in the current scope but not in lambda params).
fn collectCaptures(self: *Lowering, node: *const Node, param_names: *std.StringHashMap(void), captures: *std.ArrayList(CaptureInfo)) void {
switch (node.data) {
.identifier => |id| {
// Skip lambda params
if (param_names.contains(id.name)) return;
// Skip function names
if (self.program_index.fn_ast_map.contains(id.name)) return;
// Skip type names
if (self.program_index.struct_template_map.contains(id.name)) return;
// Check if it's a variable in the parent scope
if (self.scope) |scope| {
if (scope.lookup(id.name)) |binding| {
captures.append(self.alloc, .{
.name = id.name,
.ty = binding.ty,
.ref = binding.ref,
.is_alloca = binding.is_alloca,
}) catch {};
}
}
},
.binary_op => |bo| {
self.collectCaptures(bo.lhs, param_names, captures);
self.collectCaptures(bo.rhs, param_names, captures);
},
.unary_op => |uo| {
self.collectCaptures(uo.operand, param_names, captures);
},
.call => |cl| {
self.collectCaptures(cl.callee, param_names, captures);
for (cl.args) |arg| {
self.collectCaptures(arg, param_names, captures);
}
},
.block => |blk| {
for (blk.stmts) |stmt| {
self.collectCaptures(stmt, param_names, captures);
}
},
.if_expr => |ie| {
self.collectCaptures(ie.condition, param_names, captures);
self.collectCaptures(ie.then_branch, param_names, captures);
if (ie.else_branch) |eb| self.collectCaptures(eb, param_names, captures);
},
.while_expr => |we| {
self.collectCaptures(we.condition, param_names, captures);
self.collectCaptures(we.body, param_names, captures);
},
.return_stmt => |rs| {
if (rs.value) |v| self.collectCaptures(v, param_names, captures);
},
.var_decl => |vd| {
if (vd.value) |v| self.collectCaptures(v, param_names, captures);
// Register the local var name so it's not captured
param_names.put(vd.name, {}) catch {};
},
.const_decl => |cd| {
self.collectCaptures(cd.value, param_names, captures);
param_names.put(cd.name, {}) catch {};
},
.assignment => |a| {
self.collectCaptures(a.target, param_names, captures);
self.collectCaptures(a.value, param_names, captures);
},
.destructure_decl => |dd| {
self.collectCaptures(dd.value, param_names, captures);
for (dd.names) |name| {
param_names.put(name, {}) catch {};
}
},
.field_access => |fa| {
self.collectCaptures(fa.object, param_names, captures);
},
.index_expr => |ie| {
self.collectCaptures(ie.object, param_names, captures);
self.collectCaptures(ie.index, param_names, captures);
},
.struct_literal => |sl| {
for (sl.field_inits) |fi| {
self.collectCaptures(fi.value, param_names, captures);
}
},
.array_literal => |al| {
for (al.elements) |elem| {
self.collectCaptures(elem, param_names, captures);
}
},
.lambda => |inner_lam| {
// For nested lambdas, the inner lambda captures from our scope too
// But its own params should be excluded
var inner_params = std.StringHashMap(void).init(self.alloc);
defer inner_params.deinit();
// Copy current param_names
var it = param_names.iterator();
while (it.next()) |e| {
inner_params.put(e.key_ptr.*, {}) catch {};
}
for (inner_lam.params) |p| {
inner_params.put(p.name, {}) catch {};
}
self.collectCaptures(inner_lam.body, &inner_params, captures);
},
.match_expr => |me| {
self.collectCaptures(me.subject, param_names, captures);
for (me.arms) |arm| {
self.collectCaptures(arm.body, param_names, captures);
}
},
.null_coalesce => |nc| {
self.collectCaptures(nc.lhs, param_names, captures);
self.collectCaptures(nc.rhs, param_names, captures);
},
.deref_expr => |de| {
self.collectCaptures(de.operand, param_names, captures);
},
.for_expr => |fe| {
self.collectCaptures(fe.iterable, param_names, captures);
// Register capture name as local so it's not captured
param_names.put(fe.capture_name, {}) catch {};
self.collectCaptures(fe.body, param_names, captures);
},
.slice_expr => |se| {
self.collectCaptures(se.object, param_names, captures);
if (se.start) |s| self.collectCaptures(s, param_names, captures);
if (se.end) |e| self.collectCaptures(e, param_names, captures);
},
.tuple_literal => |tl| {
for (tl.elements) |elem| {
self.collectCaptures(elem.value, param_names, captures);
}
},
.force_unwrap => |fu| {
self.collectCaptures(fu.operand, param_names, captures);
},
.chained_comparison => |cc| {
for (cc.operands) |op| {
self.collectCaptures(op, param_names, captures);
}
},
.defer_stmt => |ds| {
self.collectCaptures(ds.expr, param_names, captures);
},
.ffi_intrinsic_call => |fic| {
self.collectCaptures(fic.return_type, param_names, captures);
for (fic.args) |arg| {
self.collectCaptures(arg, param_names, captures);
}
},
else => {},
}
}
/// Compute the byte size of the env struct based on captured value types.
fn computeEnvSize(self: *Lowering, capture_list: []const CaptureInfo) usize {
// Must match LLVM's struct layout: fields are aligned to their natural alignment
var offset: usize = 0;
var max_align: usize = 1;
for (capture_list) |cap| {
const field_size = self.typeSizeBytes(cap.ty);
const field_align = self.typeAlignBytes(cap.ty);
if (field_align > max_align) max_align = field_align;
// Align offset to field alignment
offset = (offset + field_align - 1) & ~(field_align - 1);
offset += field_size;
}
// Align total to max field alignment (matches LLVM's struct alignment)
return (offset + max_align - 1) & ~(max_align - 1);
}
/// Byte size of an IR type matching LLVM's type layout.
pub fn typeSizeBytes(self: *Lowering, ty: TypeId) usize {
return self.module.types.typeSizeBytes(ty);
}
fn typeAlignBytes(self: *Lowering, ty: TypeId) usize {
pub fn typeAlignBytes(self: *Lowering, ty: TypeId) usize {
return self.module.types.typeAlignBytes(ty);
}
@@ -2209,7 +1532,7 @@ pub const Lowering = struct {
pub const lookupGlobalIdByName = lower_objc_class.lookupGlobalIdByName;
// --- moved to lower/call.zig (lower_call) ---
pub const CaptureInfo = lower_call.CaptureInfo;
pub const CaptureInfo = lower_closure.CaptureInfo;
pub const lowerCall = lower_call.lowerCall;
pub const diagnoseMissingContext = lower_call.diagnoseMissingContext;
pub const allocViaContext = lower_call.allocViaContext;
@@ -2332,4 +1655,11 @@ pub const Lowering = struct {
pub const lowerTupleMembership = lower_expr.lowerTupleMembership;
pub const lowerChainedComparison = lower_expr.lowerChainedComparison;
pub const emitCmp = lower_expr.emitCmp;
// --- moved to lower/closure.zig (lower_closure) ---
pub const lowerLambda = lower_closure.lowerLambda;
pub const createBareFnTrampoline = lower_closure.createBareFnTrampoline;
pub const createClosureToBareFnAdapter = lower_closure.createClosureToBareFnAdapter;
pub const collectCaptures = lower_closure.collectCaptures;
pub const computeEnvSize = lower_closure.computeEnvSize;
};

8
src/ir/lower/call.zig
View File

@@ -43,7 +43,6 @@ const Function = inst_mod.Function;
const Module = mod_mod.Module;
const Builder = mod_mod.Builder;
const lower = @import("../lower.zig");
const Lowering = lower.Lowering;
const Scope = lower.Scope;
@@ -1206,13 +1205,6 @@ pub fn resolveBuiltin(name: []const u8) ?inst_mod.BuiltinId {
// ── Lambda/closure ────────────────────────────────────────────
pub const CaptureInfo = struct {
name: []const u8,
ty: TypeId,
ref: Ref, // alloca or value ref in the parent scope
is_alloca: bool,
};
/// Build `tp.name -> TypeId` bindings for a generic call.
/// `args_ast` must be parallel to `fd.params`; for dot-calls the caller
/// prepends the receiver's AST node so positions align with `fd.params[0] = self`.

733
src/ir/lower/closure.zig Normal file
View File

@@ -0,0 +1,733 @@
const std = @import("std");
const Allocator = std.mem.Allocator;
const ast = @import("../../ast.zig");
const Node = ast.Node;
const types = @import("../types.zig");
const inst_mod = @import("../inst.zig");
const mod_mod = @import("../module.zig");
const type_bridge = @import("../type_bridge.zig");
const unescape = @import("../../unescape.zig");
const parser_mod = @import("../../parser.zig");
const interp_mod = @import("../interp.zig");
const errors = @import("../../errors.zig");
const jni_descriptor = @import("../jni_descriptor.zig");
const program_index_mod = @import("../program_index.zig");
const resolver_mod = @import("../resolver.zig");
const imports_mod = @import("../../imports.zig");
const ProgramIndex = program_index_mod.ProgramIndex;
const GlobalInfo = program_index_mod.GlobalInfo;
const StructTemplate = program_index_mod.StructTemplate;
const TemplateParam = program_index_mod.TemplateParam;
const ProtocolDeclInfo = program_index_mod.ProtocolDeclInfo;
const ProtocolMethodInfo = program_index_mod.ProtocolMethodInfo;
const ModuleConstInfo = program_index_mod.ModuleConstInfo;
const TypeResolver = @import("../type_resolver.zig").TypeResolver;
const ResolveEnv = @import("../type_resolver.zig").ResolveEnv;
const PackResolver = @import("../packs.zig").PackResolver;
const ExprTyper = @import("../expr_typer.zig").ExprTyper;
const CallResolver = @import("../calls.zig").CallResolver;
const GenericResolver = @import("../generics.zig").GenericResolver;
const ProtocolResolver = @import("../protocols.zig").ProtocolResolver;
const CoercionResolver = @import("../conversions.zig").CoercionResolver;
const ErrorAnalysis = @import("../error_analysis.zig").ErrorAnalysis;
const ErrorFlow = @import("../error_flow.zig").ErrorFlow;
const ObjcLowering = @import("../ffi_objc.zig").ObjcLowering;
const semantic_diagnostics = @import("../semantic_diagnostics.zig");
const TypeId = types.TypeId;
const StringId = types.StringId;
const Ref = inst_mod.Ref;
const BlockId = inst_mod.BlockId;
const FuncId = inst_mod.FuncId;
const Function = inst_mod.Function;
const Module = mod_mod.Module;
const Builder = mod_mod.Builder;
const lower = @import("../lower.zig");
const Lowering = lower.Lowering;
const Scope = lower.Scope;
pub fn lowerLambda(self: *Lowering, lam: *const ast.Lambda) Ref {
// Lower the lambda body as a new anonymous function
var buf: [64]u8 = undefined;
const name = std.fmt.bufPrint(&buf, "__lambda_{d}", .{self.block_counter}) catch "__lambda";
self.block_counter += 1;
// Collect lambda param names for exclusion from captures
var param_names = std.StringHashMap(void).init(self.alloc);
defer param_names.deinit();
for (lam.params) |p| {
param_names.put(p.name, {}) catch {};
}
// Pre-scan lambda body AST for free variables (captures)
var captures = std.ArrayList(CaptureInfo).empty;
defer captures.deinit(self.alloc);
self.collectCaptures(lam.body, &param_names, &captures);
// Deduplicate captures
var seen = std.StringHashMap(void).init(self.alloc);
defer seen.deinit();
var deduped = std.ArrayList(CaptureInfo).empty;
defer deduped.deinit(self.alloc);
for (captures.items) |cap| {
if (!seen.contains(cap.name)) {
seen.put(cap.name, {}) catch {};
deduped.append(self.alloc, cap) catch {};
}
}
const capture_list = deduped.items;
// Build env struct type if there are captures
var env_struct_ty: TypeId = .void;
if (capture_list.len > 0) {
const env_field_data = self.alloc.alloc(types.TypeInfo.StructInfo.Field, capture_list.len) catch unreachable;
for (capture_list, 0..) |cap, i| {
var nbuf: [32]u8 = undefined;
const fname = std.fmt.bufPrint(&nbuf, "cap_{d}", .{i}) catch "cap";
env_field_data[i] = .{
.name = self.module.types.internString(fname),
.ty = cap.ty,
};
}
const env_name = std.fmt.bufPrint(&buf, "__env_{d}", .{self.block_counter}) catch "__env";
const env_name_id = self.module.types.internString(env_name);
env_struct_ty = self.module.types.intern(.{ .@"struct" = .{
.name = env_name_id,
.fields = env_field_data,
} });
}
// Save current builder state
const saved_func = self.builder.func;
const saved_block = self.builder.current_block;
const saved_counter = self.builder.inst_counter;
const saved_scope = self.scope;
// Build param list. Convention when implicit_ctx is enabled:
// slot 0 = __sx_ctx: *void
// slot 1 = env: *void
// slot 2+ = user params
// Without implicit_ctx, env is slot 0 and user params follow.
var params = std.ArrayList(Function.Param).empty;
const env_ptr_ty = self.module.types.ptrTo(.void);
const lambda_wants_ctx = self.implicit_ctx_enabled and lam.call_conv != .c;
if (lambda_wants_ctx) {
params.append(self.alloc, .{
.name = self.module.types.internString("__sx_ctx"),
.ty = env_ptr_ty,
}) catch unreachable;
}
params.append(self.alloc, .{
.name = self.module.types.internString("env"),
.ty = env_ptr_ty,
}) catch unreachable;
// Get target closure param types for inference (from Closure(T1, T2) -> R annotations)
const target_closure_params: ?[]const TypeId = if (self.target_type) |tt| blk: {
if (!tt.isBuiltin()) {
const tti = self.module.types.get(tt);
if (tti == .closure) break :blk tti.closure.params;
// Unwrap ?Closure(...) → Closure(...)
if (tti == .optional) {
const inner = tti.optional.child;
if (!inner.isBuiltin()) {
const inner_info = self.module.types.get(inner);
if (inner_info == .closure) break :blk inner_info.closure.params;
}
}
}
break :blk null;
} else null;
// User params follow the ctx (optional) + env slots in `params`.
const user_param_base: usize = (if (lambda_wants_ctx) @as(usize, 1) else 0) + 1;
for (lam.params, 0..) |p, pi| {
const pty: TypeId = blk: {
// Unannotated lambda params take their type positionally from
// the target `Closure(T0, …)` signature. Resolve them here so
// `resolveParamType` (which would diagnose a missing annotation)
// is only called for params that carry one.
if (p.type_expr.data == .inferred_type) {
if (target_closure_params != null and pi < target_closure_params.?.len) {
break :blk target_closure_params.?[pi];
}
if (self.diagnostics) |d| {
d.addFmt(.err, p.type_expr.span, "cannot infer type of lambda parameter '{s}'; annotate it or use the lambda where a closure type is expected", .{p.name});
}
break :blk .unresolved;
}
break :blk self.resolveParamType(&p);
};
params.append(self.alloc, .{
.name = self.module.types.internString(p.name),
.ty = pty,
}) catch unreachable;
}
const ret_ty = blk: {
if (lam.return_type) |rt| {
break :blk type_bridge.resolveAstType(rt, &self.module.types, &self.program_index.type_alias_map, &self.program_index.module_const_map);
}
// Use target closure return type if available — but only when it's
// a resolved type. An `.unresolved` ret comes from an unbound
// generic (`Closure(..) -> $R`); fall through to infer it from the
// body so the concrete return drives `$R` inference at the call site.
if (self.target_type) |tt| {
if (!tt.isBuiltin()) {
const tti = self.module.types.get(tt);
if (tti == .closure and tti.closure.ret != .unresolved) break :blk tti.closure.ret;
// Unwrap ?Closure(...) → Closure(...)
if (tti == .optional) {
const inner = tti.optional.child;
if (!inner.isBuiltin()) {
const inner_info = self.module.types.get(inner);
if (inner_info == .closure and inner_info.closure.ret != .unresolved) break :blk inner_info.closure.ret;
}
}
}
}
// Arrow lambda without explicit return type — infer from body expression
// Temporarily bind params in scope so inferExprType can resolve param types
var temp_scope = Scope.init(self.alloc, self.scope);
const saved = self.scope;
self.scope = &temp_scope;
for (lam.params, 0..) |p, i| {
const pty = params.items[user_param_base + i].ty;
temp_scope.put(p.name, .{ .ref = @enumFromInt(0), .ty = pty, .is_alloca = false });
}
const inferred = self.inferExprType(lam.body);
self.scope = saved;
temp_scope.deinit();
break :blk inferred;
};
const name_id = self.module.types.internString(name);
const func_id = self.builder.beginFunction(name_id, params.items, ret_ty);
if (lam.call_conv == .c) {
self.module.getFunctionMut(func_id).call_conv = .c;
}
self.builder.currentFunc().has_implicit_ctx = lambda_wants_ctx;
// Param-slot layout: ctx at 0 (if present), env at ctx_slots,
// user args at ctx_slots+1.
const lambda_ctx_slots: u32 = if (lambda_wants_ctx) 1 else 0;
const env_param_idx: u32 = lambda_ctx_slots;
const user_param_base_lam: u32 = lambda_ctx_slots + 1;
// Save + rebind current_ctx_ref so the body's sx-to-sx calls
// forward the trampoline's own ctx (slot 0).
const saved_ctx_ref_lam = self.current_ctx_ref;
defer self.current_ctx_ref = saved_ctx_ref_lam;
if (lambda_wants_ctx) self.current_ctx_ref = Ref.fromIndex(0);
// A lambda is its own function: its `return` must drain only ITS OWN
// `defer`s, not the enclosing function's. Open a fresh defer window
// (like `lowerFunction`/`monomorphizeFunction`) and restore on exit —
// otherwise lowering a closure literal inside a `defer` body re-enters
// the enclosing function's defer drain (infinite recursion — issue 0073).
const saved_func_defer_base = self.func_defer_base;
const saved_defer_len = self.defer_stack.items.len;
defer {
self.func_defer_base = saved_func_defer_base;
self.defer_stack.shrinkRetainingCapacity(saved_defer_len);
}
self.func_defer_base = saved_defer_len;
// Create entry block
const entry_name = self.module.types.internString("entry");
const entry = self.builder.appendBlock(entry_name, &.{});
self.builder.switchToBlock(entry);
// Create scope WITHOUT parent — captures are bound from env, not parent scope
var lambda_scope = Scope.init(self.alloc, null);
self.scope = &lambda_scope;
// Bind captures from env struct (at env_param_idx)
if (capture_list.len > 0) {
const env_param_ref = Ref.fromIndex(env_param_idx);
// Alloca env struct locally so struct_gep can resolve the type
const env_local = self.builder.alloca(env_struct_ty);
// Compute env size
const env_byte_size_inner = self.computeEnvSize(capture_list);
const env_size_val = self.builder.constInt(@intCast(env_byte_size_inner), .s64);
// memcpy(local_alloca, env_param, size)
_ = self.callForeign("memcpy", &.{ env_local, env_param_ref, env_size_val }, self.module.types.ptrTo(.void));
for (capture_list, 0..) |cap, i| {
// GEP into env struct to get field pointer
const field_ptr = self.builder.structGepTyped(env_local, @intCast(i), self.module.types.ptrTo(cap.ty), env_struct_ty);
// Load the captured value into a local alloca
const loaded = self.builder.load(field_ptr, cap.ty);
const slot = self.builder.alloca(cap.ty);
self.builder.store(slot, loaded);
lambda_scope.put(cap.name, .{ .ref = slot, .ty = cap.ty, .is_alloca = true });
}
}
// Also need parent scope for function lookups (but not variable lookups)
// Set up fn_names from parent scope chain
{
var s: ?*Scope = saved_scope;
while (s) |scope| {
var it = scope.fn_names.iterator();
while (it.next()) |e| {
if (!lambda_scope.fn_names.contains(e.key_ptr.*)) {
lambda_scope.fn_names.put(e.key_ptr.*, e.value_ptr.*) catch {};
}
}
s = scope.parent;
}
}
// Bind params (user args start at user_param_base_lam, shifted past ctx + env).
// Use the signature types computed above (`params`), which already
// applied contextual typing from the target closure to untyped params —
// `resolveParamType` alone would drop it and default each to s64.
for (lam.params, 0..) |p, i| {
const pty = params.items[user_param_base + i].ty;
const slot = self.builder.alloca(pty);
const param_ref = Ref.fromIndex(user_param_base_lam + @as(u32, @intCast(i)));
self.builder.store(slot, param_ref);
lambda_scope.put(p.name, .{ .ref = slot, .ty = pty, .is_alloca = true });
}
// Lower body — capture last expression as return value. The
// `in_lambda_body` flag scopes the lambda-specific `raise`-not-failable
// hint; save/restore so a lambda nested inside a regular function (or a
// lambda inside a lambda) restores the enclosing context.
const saved_in_lambda = self.in_lambda_body;
self.in_lambda_body = true;
if (ret_ty != .void) {
if (self.lowerBlockValue(lam.body)) |val| {
if (!self.currentBlockHasTerminator()) {
const val_ty = self.builder.getRefType(val);
// A value-carrying failable arrow lambda (`-> (T, !) => expr`)
// yields the bare success value; the compiler appends the
// no-error slot (0) — same as a `return v` in a block body.
if (!ret_ty.isBuiltin() and self.module.types.get(ret_ty) == .tuple and self.errorChannelOf(ret_ty) != null) {
self.lowerFailableSuccessReturn(val, ret_ty, lam.body.span);
} else {
const coerced = if (val_ty != .void) self.coerceToType(val, val_ty, ret_ty) else val;
self.builder.ret(coerced, ret_ty);
}
}
}
} else {
self.lowerBlock(lam.body);
}
self.in_lambda_body = saved_in_lambda;
self.ensureTerminator(ret_ty);
self.builder.finalize();
// Restore builder state
self.scope = saved_scope;
lambda_scope.deinit();
self.builder.func = saved_func;
self.builder.current_block = saved_block;
self.builder.inst_counter = saved_counter;
// Restore the caller's `current_ctx_ref` BEFORE we emit the env
// alloc/memcpy below — those run in the caller's scope, and
// `allocViaContext` reads `current_ctx_ref` to find the
// installed allocator. Without this, the env_heap dispatch
// would still see `Ref.fromIndex(0)` (the lambda's own ctx
// param), which doesn't exist in the caller's frame and
// silently routes through the default context instead of any
// surrounding `push Context.{ allocator = ... }`.
self.current_ctx_ref = saved_ctx_ref_lam;
// Closure flowing into a BARE function-pointer slot (`(T) -> U`, no env):
// the slot is called without the closure env arg, so the closure fn can't
// be passed directly. For a capture-free closure whose return type matches
// the slot, emit an adapter with the bare ABI. Reject the cases the bare
// ABI can't represent: a capturing closure (env has nowhere to live), and
// a failable closure into a non-failable slot (foreign code can't observe
// the error channel — ERR E5.1 FFI-boundary rule).
if (self.target_type) |tt| {
if (!tt.isBuiltin() and self.module.types.get(tt) == .function) {
const slot_ret = self.module.types.get(tt).function.ret;
const widen_ok = self.errorChannelOf(slot_ret) != null and self.errorChannelOf(ret_ty) == null and self.failableSuccessType(slot_ret) == ret_ty;
if (capture_list.len > 0) {
if (self.diagnostics) |d| d.addFmt(.err, lam.body.span, "a capturing closure cannot be passed as a bare function pointer; declare the parameter type as `Closure(...)` so its environment is carried", .{});
} else if (ret_ty == slot_ret or widen_ok) {
// Matching ABI, or a non-failable closure widening into a
// failable slot (∅ ⊆ slot set) — the adapter wraps {value, 0}.
const adapter = self.createClosureToBareFnAdapter(func_id, self.module.types.get(tt).function, ret_ty, lam.body.span);
return self.builder.emit(.{ .func_ref = adapter }, tt);
} else if (self.errorChannelOf(ret_ty) != null and self.errorChannelOf(slot_ret) == null) {
if (self.diagnostics) |d| d.addFmt(.err, lam.body.span, "failable closure cannot be assigned to a non-failable function-type slot; foreign code can't observe the error channel — handle the error in a wrapper closure that absorbs it", .{});
} else if (self.diagnostics) |d| {
d.addFmt(.err, lam.body.span, "closure return type does not match the function-type slot", .{});
}
}
}
// Create proper closure type (user-visible params only — skip ctx + env).
const skip_count: usize = if (lambda_wants_ctx) 2 else 1;
var param_types_list = std.ArrayList(TypeId).empty;
for (params.items[skip_count..]) |p| {
param_types_list.append(self.alloc, p.ty) catch unreachable;
}
const closure_ty = self.module.types.closureType(param_types_list.items, ret_ty);
// Build env and closure in the caller's scope
if (capture_list.len > 0) {
// Alloca env struct on stack (so struct_gep can resolve the type)
const env_local = self.builder.alloca(env_struct_ty);
// Store captured values into env struct fields
for (capture_list, 0..) |cap, i| {
const gep = self.builder.structGepTyped(env_local, @intCast(i), self.module.types.ptrTo(cap.ty), env_struct_ty);
const val = if (cap.is_alloca)
self.builder.load(cap.ref, cap.ty)
else
cap.ref;
self.builder.store(gep, val);
}
// Copy env to heap (so it outlives the stack frame).
// Route through `context.allocator.alloc` rather than calling
// libc malloc directly so closures respect a surrounding
// `push Context.{ allocator = ... }` and a tracker / arena
// counts the env allocation alongside everything else.
const env_byte_size = self.computeEnvSize(capture_list);
const env_size = self.builder.constInt(@intCast(env_byte_size), .s64);
const ptr_void = self.module.types.ptrTo(.void);
const env_heap = self.allocViaContext(env_size, ptr_void);
// memcpy(heap, stack_alloca, size)
_ = self.callForeign("memcpy", &.{ env_heap, env_local, env_size }, ptr_void);
return self.builder.closureCreate(func_id, env_heap, closure_ty);
} else {
return self.builder.closureCreate(func_id, Ref.none, closure_ty);
}
}
/// Create a trampoline function that wraps a bare function for closure auto-promotion.
/// The trampoline has signature `(env: *void, args...) -> ret` and simply calls the
/// bare function with `(args...)`, ignoring the env parameter.
pub fn createBareFnTrampoline(self: *Lowering, bare_func_id: FuncId, closure_info: types.TypeInfo.ClosureInfo) FuncId {
// Build trampoline params: [__sx_ctx]? + env + closure params.
// When the program uses Context, every sx-side trampoline carries
// the implicit ctx at slot 0 and forwards it to the wrapped
// function (which is also sx-side and expects it at slot 0).
var params = std.ArrayList(inst_mod.Function.Param).empty;
defer params.deinit(self.alloc);
const void_ptr_ty = self.module.types.ptrTo(.void);
const wants_ctx = self.implicit_ctx_enabled;
if (wants_ctx) {
params.append(self.alloc, .{ .name = self.module.types.internString("__sx_ctx"), .ty = void_ptr_ty }) catch unreachable;
}
const env_name = self.module.types.internString("env");
params.append(self.alloc, .{ .name = env_name, .ty = void_ptr_ty }) catch unreachable;
for (closure_info.params, 0..) |pty, i| {
var buf: [32]u8 = undefined;
const pname = std.fmt.bufPrint(&buf, "a{d}", .{i}) catch "arg";
params.append(self.alloc, .{ .name = self.module.types.internString(pname), .ty = pty }) catch unreachable;
}
// Generate unique trampoline name
const bare_func = self.module.functions.items[bare_func_id.index()];
const bare_name = self.module.types.getString(bare_func.name);
var name_buf: [128]u8 = undefined;
const tramp_name = std.fmt.bufPrint(&name_buf, "__tramp_{s}", .{bare_name}) catch "__tramp";
const tramp_name_id = self.module.types.internString(tramp_name);
// Save builder state
const saved_func = self.builder.func;
const saved_block = self.builder.current_block;
const saved_counter = self.builder.inst_counter;
// Create function
const owned_params = self.alloc.dupe(inst_mod.Function.Param, params.items) catch unreachable;
var func = inst_mod.Function.init(tramp_name_id, owned_params, closure_info.ret);
func.has_implicit_ctx = wants_ctx;
const func_id = self.module.addFunction(func);
self.builder.func = func_id;
self.builder.inst_counter = @intCast(owned_params.len); // params occupy refs 0..N-1
const entry_name = self.module.types.internString("entry");
const entry_block = self.builder.appendBlock(entry_name, &.{});
self.builder.switchToBlock(entry_block);
// Build call args: forward [__sx_ctx]? + user_params (skip env).
// Trampoline slots: 0=ctx (if present), {0|1}=env, then user args.
const ctx_slots: usize = if (wants_ctx) 1 else 0;
const user_arg_start: u32 = @intCast(ctx_slots + 1); // skip ctx + env
var call_args = std.ArrayList(Ref).empty;
defer call_args.deinit(self.alloc);
if (wants_ctx and bare_func.has_implicit_ctx) {
call_args.append(self.alloc, Ref.fromIndex(0)) catch unreachable; // forward our ctx
}
for (closure_info.params, 0..) |_, i| {
call_args.append(self.alloc, Ref.fromIndex(user_arg_start + @as(u32, @intCast(i)))) catch unreachable;
}
const owned_args = self.alloc.dupe(Ref, call_args.items) catch unreachable;
const result = self.builder.emit(.{ .call = .{ .callee = bare_func_id, .args = owned_args } }, closure_info.ret);
// Return result (or void)
if (closure_info.ret != .void) {
self.builder.ret(result, closure_info.ret);
} else {
self.builder.retVoid();
}
self.builder.finalize();
// Restore builder state
self.builder.func = saved_func;
self.builder.current_block = saved_block;
self.builder.inst_counter = saved_counter;
return func_id;
}
/// Adapter for coercing a closure into a BARE function-pointer slot
/// (`(T) -> U`, no env). The closure's underlying function has signature
/// `[ctx?] + env + user-params`, but a bare fn-ptr slot is *called* without
/// the env arg — so the closure fn can't be used directly (the env slot
/// would swallow the first user arg). This adapter carries the bare ABI
/// (`[ctx?] + user-params`) and forwards to the closure fn with a null env.
/// Only sound for capture-free closures (a null env is correct iff the body
/// reads no captures); the caller rejects capturing closures.
///
/// When `closure_ret` differs from `fn_info.ret`, this is the ∅-widening
/// case (a non-failable closure into a failable slot): the closure returns
/// the success value and the adapter wraps it into the slot's `{value, 0}`
/// failable tuple (ERR E5.1 non-failable→failable widening).
pub fn createClosureToBareFnAdapter(self: *Lowering, closure_func_id: FuncId, fn_info: types.TypeInfo.FunctionInfo, closure_ret: TypeId, span: ast.Span) FuncId {
var params = std.ArrayList(inst_mod.Function.Param).empty;
defer params.deinit(self.alloc);
const void_ptr_ty = self.module.types.ptrTo(.void);
const wants_ctx = self.implicit_ctx_enabled;
if (wants_ctx) {
params.append(self.alloc, .{ .name = self.module.types.internString("__sx_ctx"), .ty = void_ptr_ty }) catch unreachable;
}
for (fn_info.params, 0..) |pty, i| {
var buf: [32]u8 = undefined;
const pname = std.fmt.bufPrint(&buf, "a{d}", .{i}) catch "arg";
params.append(self.alloc, .{ .name = self.module.types.internString(pname), .ty = pty }) catch unreachable;
}
const closure_func = self.module.functions.items[closure_func_id.index()];
const closure_name = self.module.types.getString(closure_func.name);
var name_buf: [128]u8 = undefined;
const adapter_name = std.fmt.bufPrint(&name_buf, "__cl2fn_{s}", .{closure_name}) catch "__cl2fn";
const adapter_name_id = self.module.types.internString(adapter_name);
const saved_func = self.builder.func;
const saved_block = self.builder.current_block;
const saved_counter = self.builder.inst_counter;
const owned_params = self.alloc.dupe(inst_mod.Function.Param, params.items) catch unreachable;
var func = inst_mod.Function.init(adapter_name_id, owned_params, fn_info.ret);
func.has_implicit_ctx = wants_ctx;
const func_id = self.module.addFunction(func);
self.builder.func = func_id;
self.builder.inst_counter = @intCast(owned_params.len);
const entry_name = self.module.types.internString("entry");
const entry_block = self.builder.appendBlock(entry_name, &.{});
self.builder.switchToBlock(entry_block);
// Forward [ctx?] + null env + user params to the closure fn.
const ctx_slots: usize = if (wants_ctx) 1 else 0;
var call_args = std.ArrayList(Ref).empty;
defer call_args.deinit(self.alloc);
if (wants_ctx) call_args.append(self.alloc, Ref.fromIndex(0)) catch unreachable;
call_args.append(self.alloc, self.builder.constNull(void_ptr_ty)) catch unreachable;
for (fn_info.params, 0..) |_, i| {
call_args.append(self.alloc, Ref.fromIndex(@intCast(ctx_slots + i))) catch unreachable;
}
const owned_args = self.alloc.dupe(Ref, call_args.items) catch unreachable;
const result = self.builder.emit(.{ .call = .{ .callee = closure_func_id, .args = owned_args } }, closure_ret);
if (closure_ret == fn_info.ret) {
if (fn_info.ret != .void) {
self.builder.ret(result, fn_info.ret);
} else {
self.builder.retVoid();
}
} else {
// ∅-widening: closure returns the success value; wrap `{value, 0}`
// into the slot's failable tuple.
self.lowerFailableSuccessReturn(result, fn_info.ret, span);
}
self.builder.finalize();
self.builder.func = saved_func;
self.builder.current_block = saved_block;
self.builder.inst_counter = saved_counter;
return func_id;
}
/// Walk an AST node and collect free variable references (identifiers that are
/// in the current scope but not in lambda params).
pub fn collectCaptures(self: *Lowering, node: *const Node, param_names: *std.StringHashMap(void), captures: *std.ArrayList(CaptureInfo)) void {
switch (node.data) {
.identifier => |id| {
// Skip lambda params
if (param_names.contains(id.name)) return;
// Skip function names
if (self.program_index.fn_ast_map.contains(id.name)) return;
// Skip type names
if (self.program_index.struct_template_map.contains(id.name)) return;
// Check if it's a variable in the parent scope
if (self.scope) |scope| {
if (scope.lookup(id.name)) |binding| {
captures.append(self.alloc, .{
.name = id.name,
.ty = binding.ty,
.ref = binding.ref,
.is_alloca = binding.is_alloca,
}) catch {};
}
}
},
.binary_op => |bo| {
self.collectCaptures(bo.lhs, param_names, captures);
self.collectCaptures(bo.rhs, param_names, captures);
},
.unary_op => |uo| {
self.collectCaptures(uo.operand, param_names, captures);
},
.call => |cl| {
self.collectCaptures(cl.callee, param_names, captures);
for (cl.args) |arg| {
self.collectCaptures(arg, param_names, captures);
}
},
.block => |blk| {
for (blk.stmts) |stmt| {
self.collectCaptures(stmt, param_names, captures);
}
},
.if_expr => |ie| {
self.collectCaptures(ie.condition, param_names, captures);
self.collectCaptures(ie.then_branch, param_names, captures);
if (ie.else_branch) |eb| self.collectCaptures(eb, param_names, captures);
},
.while_expr => |we| {
self.collectCaptures(we.condition, param_names, captures);
self.collectCaptures(we.body, param_names, captures);
},
.return_stmt => |rs| {
if (rs.value) |v| self.collectCaptures(v, param_names, captures);
},
.var_decl => |vd| {
if (vd.value) |v| self.collectCaptures(v, param_names, captures);
// Register the local var name so it's not captured
param_names.put(vd.name, {}) catch {};
},
.const_decl => |cd| {
self.collectCaptures(cd.value, param_names, captures);
param_names.put(cd.name, {}) catch {};
},
.assignment => |a| {
self.collectCaptures(a.target, param_names, captures);
self.collectCaptures(a.value, param_names, captures);
},
.destructure_decl => |dd| {
self.collectCaptures(dd.value, param_names, captures);
for (dd.names) |name| {
param_names.put(name, {}) catch {};
}
},
.field_access => |fa| {
self.collectCaptures(fa.object, param_names, captures);
},
.index_expr => |ie| {
self.collectCaptures(ie.object, param_names, captures);
self.collectCaptures(ie.index, param_names, captures);
},
.struct_literal => |sl| {
for (sl.field_inits) |fi| {
self.collectCaptures(fi.value, param_names, captures);
}
},
.array_literal => |al| {
for (al.elements) |elem| {
self.collectCaptures(elem, param_names, captures);
}
},
.lambda => |inner_lam| {
// For nested lambdas, the inner lambda captures from our scope too
// But its own params should be excluded
var inner_params = std.StringHashMap(void).init(self.alloc);
defer inner_params.deinit();
// Copy current param_names
var it = param_names.iterator();
while (it.next()) |e| {
inner_params.put(e.key_ptr.*, {}) catch {};
}
for (inner_lam.params) |p| {
inner_params.put(p.name, {}) catch {};
}
self.collectCaptures(inner_lam.body, &inner_params, captures);
},
.match_expr => |me| {
self.collectCaptures(me.subject, param_names, captures);
for (me.arms) |arm| {
self.collectCaptures(arm.body, param_names, captures);
}
},
.null_coalesce => |nc| {
self.collectCaptures(nc.lhs, param_names, captures);
self.collectCaptures(nc.rhs, param_names, captures);
},
.deref_expr => |de| {
self.collectCaptures(de.operand, param_names, captures);
},
.for_expr => |fe| {
self.collectCaptures(fe.iterable, param_names, captures);
// Register capture name as local so it's not captured
param_names.put(fe.capture_name, {}) catch {};
self.collectCaptures(fe.body, param_names, captures);
},
.slice_expr => |se| {
self.collectCaptures(se.object, param_names, captures);
if (se.start) |s| self.collectCaptures(s, param_names, captures);
if (se.end) |e| self.collectCaptures(e, param_names, captures);
},
.tuple_literal => |tl| {
for (tl.elements) |elem| {
self.collectCaptures(elem.value, param_names, captures);
}
},
.force_unwrap => |fu| {
self.collectCaptures(fu.operand, param_names, captures);
},
.chained_comparison => |cc| {
for (cc.operands) |op| {
self.collectCaptures(op, param_names, captures);
}
},
.defer_stmt => |ds| {
self.collectCaptures(ds.expr, param_names, captures);
},
.ffi_intrinsic_call => |fic| {
self.collectCaptures(fic.return_type, param_names, captures);
for (fic.args) |arg| {
self.collectCaptures(arg, param_names, captures);
}
},
else => {},
}
}
/// Compute the byte size of the env struct based on captured value types.
pub fn computeEnvSize(self: *Lowering, capture_list: []const CaptureInfo) usize {
// Must match LLVM's struct layout: fields are aligned to their natural alignment
var offset: usize = 0;
var max_align: usize = 1;
for (capture_list) |cap| {
const field_size = self.typeSizeBytes(cap.ty);
const field_align = self.typeAlignBytes(cap.ty);
if (field_align > max_align) max_align = field_align;
// Align offset to field alignment
offset = (offset + field_align - 1) & ~(field_align - 1);
offset += field_size;
}
// Align total to max field alignment (matches LLVM's struct alignment)
return (offset + max_align - 1) & ~(max_align - 1);
}
pub const CaptureInfo = struct {
name: []const u8,
ty: TypeId,
ref: Ref, // alloca or value ref in the parent scope
is_alloca: bool,
};