typed alloc

LANGUAGE.md

@@ -23,6 +23,7 @@ roadmap and milestone history.
 - target-dependent C scalar primitives from `c_char` through `c_longdouble`, kept semantically distinct from native scalars
 - contextual integer/float/character literals, backward type-demand inference through names and arithmetic, and compile-time folding for numeric constant expressions
 - strict numeric conversion by default, widening where valid, C scalar coercions at C boundaries, and explicit scalar keyword casts such as `i32(x)` / `c_float(x)`
+- compile-time `min_value(T)` and `max_value(T)` bounds for concrete native and C integer scalar types
 - arrays `[N]T`, inferred-count arrays `[_]T`, sentinel arrays `[N;S]T`, compile-time expression array counts, slices `[]T` / `[;S]T`, single-item pointers `@T`, many-item pointers `*T`, and sentinel many-item pointers `[*;S]T`
 - pointer mutability via `mut`, optional pointers as nullable pointers, pointer arithmetic for many-item pointers, postfix dereference `^`, and trapping optional unwrap `?`
 - pointer-to-array `.len`, indexing, slicing, `.ptr` on slices and pointers-to-arrays, implicit address-taking for array-variable slices, and pointer/slice sentinel weakening
@@ -73,7 +74,7 @@ roadmap and milestone history.
 
 ### standard packages
 
-- `std/mem` allocator contract over byte allocation: `Allocator` with `?*mut anyopaque` context plus `alloc`, `realloc`, and `free`; failed nonzero reallocation preserves the original allocation, while zero size frees it
+- `std/mem` allocator contract with a context pointer plus shared `AllocatorVTable`, raw byte operations `raw_alloc` / `raw_realloc` / `raw_free`, and fallible typed `alloc(T, allocator, count)`; failed nonzero raw reallocation preserves the original allocation, while zero size frees it
 
 ### compiler behavior
 

compiler/checker/checker.odin

@@ -281,13 +281,15 @@ is_ptr_cast_call :: proc(checker: ^Checker, expr: ast.Expr) -> bool {
 	       symbol_text(checker, expr.name) == "ptr_cast"
 }
 
-Layout_Builtin :: enum u8 {
+Type_Builtin :: enum u8 {
 	None,
 	Size_Of,
 	Align_Of,
+	Min_Value,
+	Max_Value,
 }
 
-layout_builtin_call :: proc(checker: ^Checker, expr: ast.Expr) -> Layout_Builtin {
+type_builtin_call :: proc(checker: ^Checker, expr: ast.Expr) -> Type_Builtin {
 	if expr.kind != .Call || expr.left != ast.INVALID_EXPR || symbol.is_valid(expr.qualifier) {
 		return .None
 	}
@@ -298,6 +300,12 @@ layout_builtin_call :: proc(checker: ^Checker, expr: ast.Expr) -> Layout_Builtin
 	if name == "align_of" {
 		return .Align_Of
 	}
+	if name == "min_value" {
+		return .Min_Value
+	}
+	if name == "max_value" {
+		return .Max_Value
+	}
 	return .None
 }
 
@@ -314,21 +322,30 @@ valid_layout_type :: proc(checker: ^Checker, value: types.Type) -> bool {
 	return types.is_runtime_value(value, &checker.module.types)
 }
 
-layout_builtin_value :: proc(checker: ^Checker, kind: Layout_Builtin, value: types.Type) -> i128 {
+type_builtin_value :: proc(checker: ^Checker, kind: Type_Builtin, value: types.Type) -> i128 {
 	#partial switch kind {
 	case .Size_Of:
 		return i128(types.size(value, &checker.module.types, checker.target))
 	case .Align_Of:
 		return i128(types.alignment_of(value, &checker.module.types, checker.target))
+	case .Min_Value:
+		if types.is_unsigned(value, checker.target) {
+			return 0
+		}
+		return -(i128(1) << u32(types.bits(value, checker.target)-1))
+	case .Max_Value:
+		bit_count := types.bits(value, checker.target)
+		sign_bit_count := 1 if types.is_signed(value, checker.target) else 0
+		return (i128(1) << u32(bit_count-sign_bit_count))-1
 	case:
 		return 0
 	}
 }
 
-build_layout_builtin :: proc(
+build_type_builtin :: proc(
 	checker: ^Checker,
 	expr: ast.Expr,
-	kind: Layout_Builtin,
+	kind: Type_Builtin,
 	pkg: ast.Package_Id,
 	file: ast.File_Id,
 ) -> hir.Expr_Id {
@@ -338,18 +355,24 @@ build_layout_builtin :: proc(
 	}
 	target, target_ok := resolve_type_argument(checker, expr.args[0], pkg, file)
 	if !target_ok {
-		id := source.add(checker.diagnostics, checker.ast_module.exprs[expr.args[0]].span, "layout target must be a type")
+		label := "layout" if kind == .Size_Of || kind == .Align_Of else "integer bound"
+		id := source.addf(checker.diagnostics, checker.ast_module.exprs[expr.args[0]].span, "%s target must be a type", label)
 		return invalid_hir_expr(checker, expr.span, id, types.USIZE)
 	}
-	if !valid_layout_type(checker, target) {
+	if (kind == .Size_Of || kind == .Align_Of) && !valid_layout_type(checker, target) {
 		id := source.addf(checker.diagnostics, checker.ast_module.exprs[expr.args[0]].span, "layout target must be a sized runtime value type, got %s", type_label(checker, target))
 		return invalid_hir_expr(checker, expr.span, id, types.USIZE)
 	}
+	if (kind == .Min_Value || kind == .Max_Value) && !types.is_concrete_integer(target) {
+		id := source.addf(checker.diagnostics, checker.ast_module.exprs[expr.args[0]].span, "integer bound target must be a concrete integer type, got %s", type_label(checker, target))
+		return invalid_hir_expr(checker, expr.span, id, types.USIZE)
+	}
+	result_type := types.USIZE if kind == .Size_Of || kind == .Align_Of else target
 	return build_constant_expr(
 		checker,
 		expr,
-		Constant{kind=.Value, value=layout_builtin_value(checker, kind, target)},
+		Constant{kind=.Value, value=type_builtin_value(checker, kind, target)},
-		types.USIZE,
+		result_type,
 	)
 }
 
@@ -2201,8 +2224,15 @@ infer_expr :: proc(
 					}
 					continue
 				}
-				if builtin := layout_builtin_call(checker, expr); builtin != .None {
+				if builtin := type_builtin_call(checker, expr); builtin != .None {
-					last = types.USIZE
+					if builtin == .Size_Of || builtin == .Align_Of {
+						last = types.USIZE
+					} else if len(expr.args) == 1 {
+						target, ok := resolve_type_argument(checker, expr.args[0], pkg, file)
+						last = target if ok && types.is_concrete_integer(target) else types.INVALID
+					} else {
+						last = types.INVALID
+					}
 					_ = pop(&stack)
 					continue
 				}
@@ -3188,10 +3218,19 @@ infer_all :: proc(checker: ^Checker) {
 		if global.external {
 			continue
 		}
-		if global.expr != ast.INVALID_EXPR && int(global.expr) < len(checker.ast_module.exprs) &&
+		if global.expr != ast.INVALID_EXPR && int(global.expr) < len(checker.ast_module.exprs) {
-		   layout_builtin_call(checker, checker.ast_module.exprs[global.expr]) != .None {
+			expr := checker.ast_module.exprs[global.expr]
-			checker.global_types[index] = types.USIZE
+			if builtin := type_builtin_call(checker, expr); builtin != .None {
-			continue
+				if builtin == .Size_Of || builtin == .Align_Of {
+					checker.global_types[index] = types.USIZE
+				} else if len(expr.args) == 1 {
+					target, ok := resolve_type_argument(checker, expr.args[0], global.pkg, global.file)
+					if ok && types.is_concrete_integer(target) {
+						checker.global_types[index] = target
+					}
+				}
+				continue
+			}
 		}
 		constant := eval_integer_constant_in_context(checker, global.expr, global.pkg, global.file)
 		if constant.kind == .Value && fits_i64(constant.value) {
@@ -4998,8 +5037,8 @@ build_expr :: proc(
 					append(&stack, Build_Expr_Frame{expr=expr.left, expected=types.INVALID, template=ast.INVALID_FUNCTION})
 					continue
 				}
-				if builtin := layout_builtin_call(checker, expr); builtin != .None {
+				if builtin := type_builtin_call(checker, expr); builtin != .None {
-					last = build_layout_builtin(checker, expr, builtin, pkg, file)
+					last = build_type_builtin(checker, expr, builtin, pkg, file)
 					_ = pop(&stack)
 					continue
 				}

compiler/checker/comptime.odin

@@ -1909,18 +1909,23 @@ ct_eval_call_expr :: proc(state: ^Ct_State, expr: ast.Expr, expected: types.Type
 		}
 		return ct_eval_template_call(state, ast.Function_Id(u32(state.values[callee].index)), expr.args, expr.span, expected, depth+1)
 	}
-	if builtin := layout_builtin_call(checker, expr); builtin != .None {
+	if builtin := type_builtin_call(checker, expr); builtin != .None {
 		if len(expr.args) != 1 {
 			return INVALID_CT_VALUE, ct_flow(.Normal), ct_failf(state, .Not_Comptime, expr.span, "%s expects 1 argument, got %d", symbol_text(checker, expr.name), len(expr.args))
 		}
 		target, target_ok := resolve_type_argument(checker, expr.args[0], state.pkg, state.file)
 		if !target_ok {
-			return INVALID_CT_VALUE, ct_flow(.Normal), ct_fail(state, .Not_Comptime, checker.ast_module.exprs[expr.args[0]].span, "layout target must be a type")
+			label := "layout" if builtin == .Size_Of || builtin == .Align_Of else "integer bound"
+			return INVALID_CT_VALUE, ct_flow(.Normal), ct_failf(state, .Not_Comptime, checker.ast_module.exprs[expr.args[0]].span, "%s target must be a type", label)
 		}
-		if !valid_layout_type(checker, target) {
+		if (builtin == .Size_Of || builtin == .Align_Of) && !valid_layout_type(checker, target) {
 			return INVALID_CT_VALUE, ct_flow(.Normal), ct_failf(state, .Not_Comptime, checker.ast_module.exprs[expr.args[0]].span, "layout target must be a sized runtime value type, got %s", type_label(checker, target))
 		}
-		return ct_add_value(state, Ct_Value{kind=.Integer, type=types.USIZE, integer=layout_builtin_value(checker, builtin, target)}), ct_flow(.Normal), true
+		if (builtin == .Min_Value || builtin == .Max_Value) && !types.is_concrete_integer(target) {
+			return INVALID_CT_VALUE, ct_flow(.Normal), ct_failf(state, .Not_Comptime, checker.ast_module.exprs[expr.args[0]].span, "integer bound target must be a concrete integer type, got %s", type_label(checker, target))
+		}
+		result_type := types.USIZE if builtin == .Size_Of || builtin == .Align_Of else target
+		return ct_add_value(state, Ct_Value{kind=.Integer, type=result_type, integer=type_builtin_value(checker, builtin, target)}), ct_flow(.Normal), true
 	}
 	target_pkg, available := expr_package(checker, expr, state.pkg, state.file, false)
 	if !available {

compiler_tests.odin

@@ -1413,6 +1413,83 @@ main func() i32 {
 	testing.expect_value(t, state.exit_code, 0)
 }
 
+@(test)
+integer_bound_builtins_compile_and_run :: proc(t: ^testing.T) {
+	directory := "/tmp/brolang-test-integer-bounds"
+	main_path := "/tmp/brolang-test-integer-bounds/main.bro"
+	output := "/tmp/brolang-test-integer-bounds-output"
+	text := `MAX_U64 u64 :: max_value(u64)
+
+maximum func($T type) T {
+	return max_value(T)
+}
+
+main func() i32 {
+	if (min_value(i8) != -128) return 1
+	if (max_value(i8) != 127) return 2
+	if (min_value(u8) != 0) return 3
+	if (max_value(u8) != 255) return 4
+	if (min_value(isize) != -9223372036854775808) return 5
+	if (max_value(usize) != 18446744073709551615) return 6
+	if (MAX_U64 != 18446744073709551615) return 7
+	if (maximum(u16) != 65535) return 8
+	if (min_value(c_int) != -2147483648) return 9
+	if (max_value(c_ulong) != 18446744073709551615) return 10
+	return 0
+}
+`
+	_ = os2.remove_all(directory)
+	defer _ = os2.remove_all(directory)
+	defer _ = os.remove(output)
+	testing.expect(t, os.make_directory(directory) == nil)
+	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
+	status := compiler_core.compile_package(directory, output)
+	testing.expect_value(t, status, 0)
+	state := run_executable(output)
+	testing.expect_value(t, state.exit_code, 0)
+}
+
+@(test)
+integer_bound_builtins_reject_invalid_targets :: proc(t: ^testing.T) {
+	text := `Named :: distinct u8
+Choice :: enum { one }
+
+main func() void {
+	_ = min_value()
+	_ = max_value(u8, u16)
+	_ = min_value(1)
+	_ = max_value(int)
+	_ = max_value(f32)
+	_ = max_value(bool)
+	_ = max_value(Named)
+	_ = max_value(Choice)
+}
+`
+	source_file := source.Source{path="test.bro", text=text}
+	diagnostics := source.init_diagnostics(&source_file)
+	defer source.destroy_diagnostics(&diagnostics)
+	symbols := symbol.init_table()
+	defer symbol.destroy_table(&symbols)
+	stream := lexer.lex(&source_file, &diagnostics, &symbols)
+	defer delete(stream.items)
+	ast_module := parser.parse(&stream, &source_file, &diagnostics)
+	defer ast.destroy_module(&ast_module)
+	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
+	defer hir.destroy_module(&hir_module)
+
+	bad_arity := 0
+	bad_type := false
+	bad_target := 0
+	for diagnostic in diagnostics.items {
+		bad_arity += 1 if strings.contains(diagnostic.message, "expects 1 argument") else 0
+		bad_type = bad_type || strings.contains(diagnostic.message, "integer bound target must be a type")
+		bad_target += 1 if strings.contains(diagnostic.message, "integer bound target must be a concrete integer type") else 0
+	}
+	testing.expect_value(t, bad_arity, 2)
+	testing.expect(t, bad_type)
+	testing.expect_value(t, bad_target, 5)
+}
+
 @(test)
 layout_builtins_reject_unsized_targets :: proc(t: ^testing.T) {
 	text := `Opaque :: opaque
@@ -3281,6 +3358,7 @@ allocator_contract_c_allocator_global_lowers :: proc(t: ^testing.T) {
 
 	found_c_allocator := false
 	found_anyopaque_context := false
+	found_vtable_pointer := false
 	found_alloc_callback := false
 	found_realloc_callback := false
 	found_free_callback := false
@@ -3291,7 +3369,6 @@ allocator_contract_c_allocator_global_lowers :: proc(t: ^testing.T) {
 		found_c_allocator = true
 		for field in types.fields_for(&hir_module.types, global.type) {
 			name := symbol.resolve(&symbols, symbol.Id(field.name))
-			callback_pointer, _, _, callable := types.function_pointer(field.type, &hir_module.types)
 			if name == "context" {
 				optional_item, optional_ok := types.node(&hir_module.types, field.type)
 				if optional_ok && optional_item.kind == .Optional {
@@ -3302,10 +3379,19 @@ allocator_contract_c_allocator_global_lowers :: proc(t: ^testing.T) {
 					                           pointer_item.many &&
 					                           pointer_item.child == types.ANYOPAQUE
 				}
+			} else if name == "vtable" {
+				pointer_item, pointer_ok := types.node(&hir_module.types, field.type)
+				found_vtable_pointer = pointer_ok && pointer_item.kind == .Pointer && !pointer_item.mutable && !pointer_item.many
+				if found_vtable_pointer {
+					for callback in types.fields_for(&hir_module.types, pointer_item.child) {
+						callback_name := symbol.resolve(&symbols, symbol.Id(callback.name))
+						callback_pointer, _, _, callable := types.function_pointer(callback.type, &hir_module.types)
+						found_alloc_callback = found_alloc_callback || callback_name == "alloc" && callable && !callback_pointer.many
+						found_realloc_callback = found_realloc_callback || callback_name == "realloc" && callable && !callback_pointer.many
+						found_free_callback = found_free_callback || callback_name == "free" && callable && !callback_pointer.many
+					}
+				}
 			}
-			found_alloc_callback = found_alloc_callback || name == "alloc" && callable && !callback_pointer.many
-			found_realloc_callback = found_realloc_callback || name == "realloc" && callable && !callback_pointer.many
-			found_free_callback = found_free_callback || name == "free" && callable && !callback_pointer.many
 		}
 	}
 
@@ -3313,6 +3399,7 @@ allocator_contract_c_allocator_global_lowers :: proc(t: ^testing.T) {
 	testing.expect(t, len(ir_module.functions) > 0)
 	testing.expect(t, found_c_allocator)
 	testing.expect(t, found_anyopaque_context)
+	testing.expect(t, found_vtable_pointer)
 	testing.expect(t, found_alloc_callback)
 	testing.expect(t, found_realloc_callback)
 	testing.expect(t, found_free_callback)

examples/programs/mem_allocator/main.bro

@@ -1,5 +1,32 @@
 mem :: import "@std/mem"
 
+_probe_count func(context ?*mut anyopaque) void {
+	if context |raw| {
+		counts *mut usize :: ptr_cast(usize, raw)
+		counts[0] += 1
+	}
+}
+
+_probe_alloc func(context ?*mut anyopaque, _ usize, _ usize) ?*mut u8 {
+	_probe_count(context)
+	return none
+}
+
+_probe_realloc func(context ?*mut anyopaque, _ ?*mut u8, _ usize, _ usize, _ usize) ?*mut u8 {
+	_probe_count(context)
+	return none
+}
+
+_probe_free func(context ?*mut anyopaque, _ ?*mut u8, _ usize, _ usize) void {
+	_probe_count(context)
+}
+
+_probe_vtable mem.AllocatorVTable :: mem.AllocatorVTable {
+	alloc = _probe_alloc,
+	realloc = _probe_realloc,
+	free = _probe_free,
+}
+
 TaskList :: struct {
 	ids ?[]mut i32
 	priorities ?[]mut i32
@@ -21,17 +48,19 @@ task_list_init func(allocator mem.Allocator) TaskList {
 }
 
 alloc_i32s func(allocator mem.Allocator, count usize) ?[]mut i32 {
-	raw ?*mut u8 = mem.alloc(allocator, count * size_of(i32), align_of(i32))
+	fallback [1]mut i32 = undefined
-	if raw |bytes| {
+	failed bool = false
-		values *mut i32 = ptr_cast(i32, bytes)
+	values []mut i32 = mem.alloc(i32, allocator, count) catch |_| {
-		return values[..count]
+		failed = true
+		yield (&fallback).ptr[..0]
 	}
-	return none
+	if (failed) return none
+	return values
 }
 
 free_i32s func(allocator mem.Allocator, values ?[]mut i32) void {
 	if values |slice| {
-		mem.free(allocator, ptr_cast(u8, slice.ptr), slice.len * size_of(i32), align_of(i32))
+		mem.raw_free(allocator, ptr_cast(u8, slice.ptr), slice.len * size_of(i32), align_of(i32))
 	}
 }
 
@@ -150,7 +179,68 @@ task_list_deinit func(list @mut TaskList) void {
 }
 
 main func() i32 {
-	resized ?*mut u8 = mem.realloc(mem.c_allocator, none, 0, 4, 1)
+	if (size_of(mem.Allocator) != 16) return 31
+
+	first_calls [1]mut usize = [0]
+	second_calls [1]mut usize = [0]
+	first_allocator mem.Allocator :: mem.Allocator {
+		context = (&first_calls).ptr,
+		vtable = &_probe_vtable,
+	}
+	second_allocator mem.Allocator :: mem.Allocator {
+		context = (&second_calls).ptr,
+		vtable = &_probe_vtable,
+	}
+
+	_ = mem.raw_alloc(first_allocator, 1, 1)
+	_ = mem.raw_realloc(first_allocator, none, 0, 1, 1)
+	mem.raw_free(first_allocator, none, 0, 1)
+	_ = mem.raw_alloc(second_allocator, 1, 1)
+	if (first_calls[0] != 3 or second_calls[0] != 1) return 32
+
+	i32_fallback [1]mut i32 = undefined
+	empty_failed bool = false
+	empty []mut i32 = mem.alloc(i32, first_allocator, 0) catch |_| {
+		empty_failed = true
+		yield (&i32_fallback).ptr[..0]
+	}
+	if (empty_failed or empty.len != 0 or first_calls[0] != 3) return 34
+
+	zero_sized_fallback [1]mut [0]u8 = undefined
+	zero_sized_failed bool = false
+	zero_sized []mut [0]u8 = mem.alloc([0]u8, first_allocator, 3) catch |_| {
+		zero_sized_failed = true
+		yield (&zero_sized_fallback).ptr[..0]
+	}
+	if (zero_sized_failed or zero_sized.len != 3 or first_calls[0] != 3) return 36
+	_ = zero_sized[2]
+
+	u64_fallback [1]mut u64 = undefined
+	overflow_fallback_failed bool = false
+	overflow_fallback []mut u64 = mem.alloc(u64, first_allocator, 0) catch |_| {
+		overflow_fallback_failed = true
+		yield (&u64_fallback).ptr[..0]
+	}
+	if (overflow_fallback_failed) return 37
+	overflow_failed bool = false
+	_ = mem.alloc(u64, first_allocator, max_value(usize)) catch |_| {
+		overflow_failed = true
+		yield overflow_fallback
+	}
+	if (overflow_failed == false or first_calls[0] != 3) return 40
+
+	typed_failed bool = false
+	typed []mut i32 = mem.alloc(i32, mem.c_allocator, 4) catch |_| {
+		typed_failed = true
+		yield (&i32_fallback).ptr[..0]
+	}
+	if (typed_failed) return 38
+	defer mem.raw_free(mem.c_allocator, ptr_cast(u8, typed.ptr), typed.len * size_of(i32), align_of(i32))
+	typed[0] = 10
+	typed[3] = 20
+	if (typed[0] + typed[3] != 30) return 39
+
+	resized ?*mut u8 = mem.raw_realloc(mem.c_allocator, none, 0, 4, 1)
 	if resized |bytes| {
 		bytes[0] = 10
 		bytes[1] = 20
@@ -160,82 +250,82 @@ main func() i32 {
 		return 20
 	}
 
-	grown ?*mut u8 = mem.realloc(mem.c_allocator, resized, 4, 8, 1)
+	grown ?*mut u8 = mem.raw_realloc(mem.c_allocator, resized, 4, 8, 1)
 	if grown |bytes| {
 		resized = grown
 		if bytes[0] != 10 or bytes[1] != 20 or bytes[2] != 30 or bytes[3] != 40 {
-			mem.free(mem.c_allocator, grown, 8, 1)
+			mem.raw_free(mem.c_allocator, grown, 8, 1)
 			return 21
 		}
 	} else {
-		mem.free(mem.c_allocator, resized, 4, 1)
+		mem.raw_free(mem.c_allocator, resized, 4, 1)
 		return 22
 	}
 
-	shrunk ?*mut u8 = mem.realloc(mem.c_allocator, resized, 8, 2, 1)
+	shrunk ?*mut u8 = mem.raw_realloc(mem.c_allocator, resized, 8, 2, 1)
 	if shrunk |bytes| {
 		resized = shrunk
 		if bytes[0] != 10 or bytes[1] != 20 {
-			mem.free(mem.c_allocator, shrunk, 2, 1)
+			mem.raw_free(mem.c_allocator, shrunk, 2, 1)
 			return 23
 		}
 	} else {
-		mem.free(mem.c_allocator, resized, 8, 1)
+		mem.raw_free(mem.c_allocator, resized, 8, 1)
 		return 24
 	}
 
-	invalid ?*mut u8 = mem.realloc(mem.c_allocator, resized, 2, 4, 24)
+	invalid ?*mut u8 = mem.raw_realloc(mem.c_allocator, resized, 2, 4, 24)
 	if invalid |memory| {
-		mem.free(mem.c_allocator, memory, 4, 24)
+		mem.raw_free(mem.c_allocator, memory, 4, 24)
-		mem.free(mem.c_allocator, resized, 2, 1)
+		mem.raw_free(mem.c_allocator, resized, 2, 1)
 		return 25
 	}
 	if resized |bytes| {
 		if bytes[0] != 10 or bytes[1] != 20 {
-			mem.free(mem.c_allocator, resized, 2, 1)
+			mem.raw_free(mem.c_allocator, resized, 2, 1)
 			return 26
 		}
 	}
 
-	resized = mem.realloc(mem.c_allocator, resized, 2, 0, 1)
+	resized = mem.raw_realloc(mem.c_allocator, resized, 2, 0, 1)
 	if resized |memory| {
-		mem.free(mem.c_allocator, memory, 0, 1)
+		mem.raw_free(mem.c_allocator, memory, 0, 1)
 		return 27
 	}
 
-	over_aligned ?*mut u8 = mem.alloc(mem.c_allocator, 4, 32)
+	over_aligned ?*mut u8 = mem.raw_alloc(mem.c_allocator, 4, 32)
 	if over_aligned |bytes| {
 		bytes[0] = 11
 		bytes[1] = 22
 	} else {
 		return 28
 	}
-	over_aligned_grown ?*mut u8 = mem.realloc(mem.c_allocator, over_aligned, 4, 8, 32)
+	over_aligned_grown ?*mut u8 = mem.raw_realloc(mem.c_allocator, over_aligned, 4, 8, 32)
 	if over_aligned_grown |bytes| {
 		if bytes[0] != 11 or bytes[1] != 22 {
-			mem.free(mem.c_allocator, over_aligned_grown, 8, 32)
+			mem.raw_free(mem.c_allocator, over_aligned_grown, 8, 32)
 			return 29
 		}
-		mem.free(mem.c_allocator, over_aligned_grown, 8, 32)
+		mem.raw_free(mem.c_allocator, over_aligned_grown, 8, 32)
 	} else {
-		mem.free(mem.c_allocator, over_aligned, 4, 32)
+		mem.raw_free(mem.c_allocator, over_aligned, 4, 32)
 		return 30
 	}
 
-	zero_alignment ?*mut u8 = mem.alloc(mem.c_allocator, 8, 0)
+	zero_alignment ?*mut u8 = mem.raw_alloc(mem.c_allocator, 8, 0)
 	if zero_alignment |memory| {
-		mem.free(mem.c_allocator, memory, 8, 0)
+		mem.raw_free(mem.c_allocator, memory, 8, 0)
 		return 1
 	}
 
-	bad_alignment ?*mut u8 = mem.alloc(mem.c_allocator, 8, 24)
+	bad_alignment ?*mut u8 = mem.raw_alloc(mem.c_allocator, 8, 24)
 	if bad_alignment |memory| {
-		mem.free(mem.c_allocator, memory, 8, 24)
+		mem.raw_free(mem.c_allocator, memory, 8, 24)
 		return 2
 	}
 
-	aligned ?*mut u8 = mem.alloc(mem.c_allocator, 64, 32)
+	aligned ?*mut u8 = mem.raw_alloc(mem.c_allocator, 64, 32)
-	defer mem.free(mem.c_allocator, aligned, 64, 32)
+	defer mem.raw_free(mem.c_allocator, aligned, 64, 32)
 	if aligned |bytes| {
 		bytes[0] = 1
 		bytes[63] = 2

std/mem/mem.bro

@@ -1,22 +1,58 @@
 c :: import "@ffi/c"
 
-Allocator :: struct {
+AllocatorVTable :: struct {
-	context ?*mut anyopaque
 	alloc @func(context ?*mut anyopaque, size usize, alignment usize) ?*mut u8
 	realloc @func(context ?*mut anyopaque, memory ?*mut u8, old_size usize, new_size usize, alignment usize) ?*mut u8
 	free @func(context ?*mut anyopaque, memory ?*mut u8, size usize, alignment usize) void
 }
 
-alloc func(allocator Allocator, size usize, alignment usize) ?*mut u8 {
+Allocator :: struct {
-	return allocator.alloc(allocator.context, size, alignment)
+	context ?*mut anyopaque
+	vtable @AllocatorVTable
 }
 
-realloc func(allocator Allocator, memory ?*mut u8, old_size usize, new_size usize, alignment usize) ?*mut u8 {
+AllocError :: enum {
-	return allocator.realloc(allocator.context, memory, old_size, new_size, alignment)
+	out_of_memory
 }
 
-free func(allocator Allocator, memory ?*mut u8, size usize, alignment usize) void {
+raw_alloc func(allocator Allocator, size usize, alignment usize) ?*mut u8 {
-	allocator.free(allocator.context, memory, size, alignment)
+	return allocator.vtable.alloc(allocator.context, size, alignment)
+}
+
+raw_realloc func(allocator Allocator, memory ?*mut u8, old_size usize, new_size usize, alignment usize) ?*mut u8 {
+	return allocator.vtable.realloc(allocator.context, memory, old_size, new_size, alignment)
+}
+
+raw_free func(allocator Allocator, memory ?*mut u8, size usize, alignment usize) void {
+	allocator.vtable.free(allocator.context, memory, size, alignment)
+}
+
+_empty_storage [1]mut u64 = [0]
+
+_empty_slice func($T type, count usize) []mut T {
+	pointer *mut T :: ptr_cast(T, (&_empty_storage).ptr)
+	return pointer[..count]
+}
+
+alloc func($T type, allocator Allocator, count usize) []mut T ! AllocError {
+	if count == 0 {
+		return _empty_slice(T, 0)
+	}
+
+	element_size usize :: size_of(T)
+	if element_size == 0 {
+		return _empty_slice(T, count)
+	}
+	if count > max_value(usize) / element_size {
+		return .out_of_memory
+	}
+
+	memory ?*mut u8 = raw_alloc(allocator, count * element_size, align_of(T))
+	if memory |bytes| {
+		pointer *mut T :: ptr_cast(T, bytes)
+		return pointer[..count]
+	}
+	return .out_of_memory
 }
 
 _malloc_alignment usize :: 16 # ponytail: aarch64-macos libc malloc alignment assumption.
@@ -93,9 +129,13 @@ _c_free func(_ ?*mut anyopaque, memory ?*mut u8, _ usize, _ usize) void {
 	c.free(memory)
 }
 
-c_allocator Allocator :: Allocator {
+_c_vtable AllocatorVTable :: AllocatorVTable {
-	context = none,
 	alloc = _c_alloc,
 	realloc = _c_realloc,
 	free = _c_free,
 }
+
+c_allocator Allocator :: Allocator {
+	context = none,
+	vtable = &_c_vtable,
+}