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fibers: rename ABI variant .pure -> .naked

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"pure" universally means side-effect-free (GCC __attribute__((pure)),
FP purity, D's pure) — the opposite of a register-clobbering context
switch. The concept is "naked": no compiler-generated prologue/epilogue,
body is raw asm that emits its own ret. That is the established term
everywhere (LLVM's naked function attribute — which we literally emit —
plus Zig callconv(.naked), Rust #[naked], GCC/Clang __attribute__
((naked))). Rename the keyword + everything keyed off it so concept,
surface, field, and the emitted LLVM attribute all agree.

- ast.zig: ABI enum variant pure -> naked (+ doc).
- parser: accept abi(.naked); error text updated.
- IR Function.is_pure -> is_naked; type_resolver/decl/generic/pack/
  emit_llvm references updated; diagnostics say abi(.naked).
- examples 1800-1803 renamed *-pure-* -> *-naked-* (source + expected/
  snapshots; .ir/.exit/.stdout/.stderr are byte-identical — the emitted
  IR is unchanged, only the keyword spelling differs).
- docs (PLAN-FIBERS, CHECKPOINT-FIBERS, PLAN-POST-METATYPE, the design
  roadmap, the compiler-API checkpoint/design) updated; the naming
  rationale now records why .naked over .pure.

No semantic change — pure cosmetics. Suite green (725/0).
This commit is contained in:
agra
2026-06-20 17:01:09 +03:00
parent b631590574
commit a7fe165684
40 changed files with 175 additions and 171 deletions
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8
src/ir/emit_llvm.test.zig
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@@ -1325,18 +1325,18 @@ test "emit: reflectArgRepr surfaces .unresolved for an unresolvable reflection a
try std.testing.expect(emitter.reflectArgRepr(bogus) != .bare);
}
test "emit: abi(.pure) function gets the naked attribute (no frame-pointer)" {
test "emit: abi(.naked) function gets the naked attribute (no frame-pointer)" {
const alloc = std.testing.allocator;
var module = Module.init(alloc);
defer module.deinit();
var b = Builder.init(&module);
// func answer() -> i64 abi(.pure) { asm volatile { "ret" }; unreachable }
// The naked attribute is keyed off Function.is_pure in the declaration pass,
// func answer() -> i64 abi(.naked) { asm volatile { "ret" }; unreachable }
// The naked attribute is keyed off Function.is_naked in the declaration pass,
// independent of the body — a minimal asm + unreachable body suffices.
_ = b.beginFunction(str(&module, "answer"), &.{}, .i64);
b.currentFunc().is_pure = true;
b.currentFunc().is_naked = true;
const entry = b.appendBlock(str(&module, "entry"), &.{});
b.switchToBlock(entry);

10
src/ir/emit_llvm.zig
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@@ -408,9 +408,9 @@ pub const LLVMEmitter = struct {
// its only references are in comptime code, so DCE drops the leftover
// declaration. See current/PLAN-COMPILER-VM.md (S3).
if (func.is_compiler_domain) continue;
// `abi(.pure)` functions emit normally — the `naked` attribute (set
// `abi(.naked)` functions emit normally — the `naked` attribute (set
// in the declaration pass) makes the backend emit the body (inline
// asm + its own `ret`) with no prologue/epilogue. See Function.is_pure.
// asm + its own `ret`) with no prologue/epilogue. See Function.is_naked.
self.emitFunction(&func, @intCast(i));
}
@@ -1327,13 +1327,13 @@ pub const LLVMEmitter = struct {
// Add frame-pointer and nounwind attributes for correct ARM64 codegen
{
const func_idx_attr: c.LLVMAttributeIndex = @bitCast(@as(i32, -1));
if (func.is_pure) {
// `abi(.pure)`: emit via LLVM's `naked` attribute — the backend
if (func.is_naked) {
// `abi(.naked)`: emit via LLVM's `naked` attribute — the backend
// emits the body verbatim (our inline asm + its own `ret`) with
// NO prologue/epilogue/frame. Do NOT request `frame-pointer`
// (incompatible with a frameless function). `noinline` keeps the
// asm body out of a framed caller; `nounwind` — naked asm never
// unwinds. See Function.is_pure / current/PLAN-FIBERS.md.
// unwinds. See Function.is_naked / current/PLAN-FIBERS.md.
const naked_id = c.LLVMGetEnumAttributeKindForName("naked", 5);
c.LLVMAddAttributeAtIndex(llvm_func, func_idx_attr, c.LLVMCreateEnumAttribute(self.context, naked_id, 0));
const noinline_id = c.LLVMGetEnumAttributeKindForName("noinline", 8);

6
src/ir/inst.zig
View File

@@ -640,15 +640,15 @@ pub const Function = struct {
/// drops the leftover declaration. See current/PLAN-COMPILER-VM.md (S3).
is_compiler_domain: bool = false,
/// True for an `abi(.pure)` function — no calling-convention
/// True for an `abi(.naked)` function — no calling-convention
/// prologue/epilogue/frame, no implicit `__sx_ctx`. Its body is a single
/// inline-asm block that reads args from ABI registers and emits its own
/// `ret` (the context-switch primitive; design §4.6). emit_llvm lowers this
/// via LLVM's `naked` function attribute and generates no frame setup. A
/// `.c` epilogue would restore SP from the wrong stack across a context
/// switch (SP-in ≠ SP-out by design), which is why `.pure` is distinct
/// switch (SP-in ≠ SP-out by design), which is why `.naked` is distinct
/// from `.c`.
is_pure: bool = false,
is_naked: bool = false,
pub const Param = struct {
name: StringId,

26
src/ir/lower/decl.zig
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@@ -513,11 +513,11 @@ pub fn detectContextDecl(decls: []const *const Node) bool {
pub fn funcWantsImplicitCtx(self: *const Lowering, fd: *const ast.FnDecl) bool {
if (!self.implicit_ctx_enabled) return false;
if (fd.abi == .c) return false;
// An `abi(.pure)` function has no frame and no synthetic params — its body
// An `abi(.naked)` function has no frame and no synthetic params — its body
// is a single asm block reading args from ABI registers. No implicit
// `__sx_ctx` (it would occupy a register slot the asm doesn't expect).
// See Function.is_pure.
if (fd.abi == .pure) return false;
// See Function.is_naked.
if (fd.abi == .naked) return false;
// A BODILESS `abi(.compiler)` decl (compiler-API surface) is dispatched by name
// to a Zig/VM handler with exactly the declared args; an implicit `__sx_ctx`
// prepend would shift every arg (breaking the handler's arity check). No sx
@@ -2315,7 +2315,7 @@ pub fn declareFunction(self: *Lowering, fd: *const ast.FnDecl, name: []const u8)
func.source_file = self.current_source_file;
func.is_variadic = is_variadic;
func.has_implicit_ctx = wants_ctx;
func.is_pure = (fd.abi == .pure);
func.is_naked = (fd.abi == .naked);
self.extern_name_map.put(name, c_name) catch {};
self.fn_decl_fids.put(fd, fid) catch {};
return;
@@ -2329,7 +2329,7 @@ pub fn declareFunction(self: *Lowering, fd: *const ast.FnDecl, name: []const u8)
func.source_file = self.current_source_file;
func.is_variadic = is_variadic;
func.has_implicit_ctx = wants_ctx;
func.is_pure = (fd.abi == .pure);
func.is_naked = (fd.abi == .naked);
if (weldedCompilerFn(self, fd, name)) func.compiler_welded = true;
// A BODIED `abi(.compiler)` function is a user compiler-domain function (e.g. a
// post-link callback): the VM runs its sx body, but it NEVER runs in the binary
@@ -2660,13 +2660,13 @@ pub fn lowerFunctionBodyInto(self: *Lowering, fd: *const ast.FnDecl, fid: FuncId
const user_param_base: u32 = if (wants_ctx) 1 else 0;
if (wants_ctx) self.current_ctx_ref = Ref.fromIndex(0);
// An `abi(.pure)` (naked) function has no frame: its params arrive in ABI
// An `abi(.naked)` (naked) function has no frame: its params arrive in ABI
// registers and are read directly by the asm body (e.g. `swap_context`'s
// `from`/`to`). Spilling them to allocas would (a) need a frame and (b) emit
// `store i64 %0, …` — "cannot use argument of naked function" (LLVM verifier).
// Leave the LLVM args declared-but-unused (the verifier allows that); the asm
// references the registers.
if (fd.abi != .pure) for (fd.params, 0..) |p, i| {
if (fd.abi != .naked) for (fd.params, 0..) |p, i| {
const pty = self.resolveParamType(&p);
const slot = self.builder.alloca(pty);
const param_ref = Ref.fromIndex(@intCast(i + user_param_base));
@@ -2685,8 +2685,8 @@ pub fn lowerFunctionBodyInto(self: *Lowering, fd: *const ast.FnDecl, fid: FuncId
// Lower the function body (set target_type to return type for implicit returns)
const saved_target = self.target_type;
self.target_type = if (ret_ty != .void and ret_ty != .noreturn) ret_ty else null;
if (self.builder.currentFunc().is_pure) {
// `abi(.pure)`: the body is a single asm block that emits its own `ret`.
if (self.builder.currentFunc().is_naked) {
// `abi(.naked)`: the body is a single asm block that emits its own `ret`.
// There is no sx-level value return — lower the statements and cap the
// block with `unreachable` (control never falls back into sx). This
// bypasses the implicit-return machinery, which would otherwise reject
@@ -2818,10 +2818,10 @@ pub fn lowerFunction(self: *Lowering, fd: *const ast.FnDecl, name: []const u8, i
const user_param_base_lf: u32 = if (wants_ctx_lf) 1 else 0;
if (wants_ctx_lf) self.current_ctx_ref = Ref.fromIndex(0);
// `abi(.pure)` (naked): params arrive in registers, read directly by the asm
// `abi(.naked)` (naked): params arrive in registers, read directly by the asm
// body — no frame, no alloca/store (which the LLVM verifier rejects on a
// naked function). See the sibling guard in the other body-lowering path.
if (fd.abi != .pure) for (fd.params, 0..) |p, i| {
if (fd.abi != .naked) for (fd.params, 0..) |p, i| {
const pty = self.resolveParamType(&p);
// Allocate stack slot for param, store initial value.
// Refs 0..N-1 are reserved for function parameters by beginFunction.
@@ -2843,8 +2843,8 @@ pub fn lowerFunction(self: *Lowering, fd: *const ast.FnDecl, name: []const u8, i
// Lower the function body, capturing the last expression's value for implicit return
const saved_target = self.target_type;
self.target_type = if (ret_ty != .void and ret_ty != .noreturn) ret_ty else null;
if (self.builder.currentFunc().is_pure) {
// `abi(.pure)`: asm-only body that rets itself — see the sibling path
if (self.builder.currentFunc().is_naked) {
// `abi(.naked)`: asm-only body that rets itself — see the sibling path
// above. Lower statements, cap with `unreachable`; emission is B1.0b.
self.lowerBlock(fd.body);
if (!self.currentBlockHasTerminator()) self.builder.emitUnreachable();

12
src/ir/lower/generic.zig
View File

@@ -115,7 +115,7 @@ pub fn monomorphizeFunction(self: *Lowering, fd: *const ast.FnDecl, mangled_name
const func_id = self.builder.beginFunction(name_id, params.items, ret_ty);
_ = func_id;
self.builder.currentFunc().has_implicit_ctx = wants_ctx;
self.builder.currentFunc().is_pure = (fd.abi == .pure);
self.builder.currentFunc().is_naked = (fd.abi == .naked);
// Create entry block
const entry_name = self.module.types.internString("entry");
@@ -128,10 +128,10 @@ pub fn monomorphizeFunction(self: *Lowering, fd: *const ast.FnDecl, mangled_name
defer scope.deinit();
self.scope = &scope;
// `abi(.pure)` (naked): no frame — params arrive in registers, read by the
// `abi(.naked)` (naked): no frame — params arrive in registers, read by the
// asm body, never spilled to allocas (the LLVM verifier rejects a naked
// function that uses its arguments). Mirrors the decl-path guard.
if (fd.abi != .pure) {
if (fd.abi != .naked) {
var param_idx: u32 = if (wants_ctx) 1 else 0;
for (fd.params) |p| {
if (isTypeParamDecl(&p, fd.type_params)) continue;
@@ -155,10 +155,10 @@ pub fn monomorphizeFunction(self: *Lowering, fd: *const ast.FnDecl, mangled_name
self.ensureTerminator(ret_ty);
}
self.builder.finalize();
} else if (self.builder.currentFunc().is_pure) {
// `abi(.pure)`: asm-only body that rets itself — no sx value return.
} else if (self.builder.currentFunc().is_naked) {
// `abi(.naked)`: asm-only body that rets itself — no sx value return.
// Lower the statements + cap with `unreachable` (mirrors the decl path).
// emit_llvm bails on `is_pure` until B1.0b implements `naked` emission.
// emit_llvm bails on `is_naked` until B1.0b implements `naked` emission.
self.lowerBlock(fd.body);
if (!self.currentBlockHasTerminator()) self.builder.emitUnreachable();
self.builder.finalize();

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

@@ -949,7 +949,7 @@ pub fn monomorphizePackFn(
const name_id = self.module.types.internString(owned_name);
_ = self.builder.beginFunction(name_id, params.items, ret_ty);
self.builder.currentFunc().has_implicit_ctx = wants_ctx;
self.builder.currentFunc().is_pure = (fd.abi == .pure);
self.builder.currentFunc().is_naked = (fd.abi == .naked);
const entry_name = self.module.types.internString("entry");
const entry = self.builder.appendBlock(entry_name, &.{});
@@ -1039,10 +1039,10 @@ pub fn monomorphizePackFn(
defer self.setCurrentSourceFile(saved_source);
if (fd.body.source_file) |src| self.setCurrentSourceFile(src);
if (self.builder.currentFunc().is_pure) {
// `abi(.pure)`: asm-only body that rets itself — no sx value return.
if (self.builder.currentFunc().is_naked) {
// `abi(.naked)`: asm-only body that rets itself — no sx value return.
// Lower statements + cap with `unreachable` (mirrors the decl path).
// emit_llvm bails on `is_pure` until B1.0b implements `naked` emission.
// emit_llvm bails on `is_naked` until B1.0b implements `naked` emission.
self.lowerBlock(fd.body);
if (!self.currentBlockHasTerminator()) self.builder.emitUnreachable();
} else if (ret_ty != .void) {

4
src/ir/type_resolver.zig
View File

@@ -228,13 +228,13 @@ pub const TypeResolver = struct {
const cc: types.TypeInfo.CallConv = switch (ft.abi) {
.default => .default,
.c => .c,
// `.compiler` (compiler-domain fn) and `.pure` (naked asm) are
// `.compiler` (compiler-domain fn) and `.naked` (naked asm) are
// decl-level ABIs with no function-pointer-type calling
// convention of their own; the IR function-type CC models only
// sx-default vs C. An `abi(.compiler)` function-TYPE param marks
// the bound function compiler-domain (handled at the call/bind
// site, not here) — its CC is still sx-default.
.compiler, .pure => .default,
.compiler, .naked => .default,
};
break :blk table.functionTypeCC(param_ids.items, ret_ty, cc);
},