add constcast and immutable free

compiler_tests.odin

@@ -2184,6 +2184,148 @@ main func() void {
 	testing.expect(t, found_target_type)
 }
 
+@(test)
+constcast_restores_pointer_and_slice_mutability :: proc(t: ^testing.T) {
+	text := `main func() i32 {
+	values [2]mut u8 = [1, 2]
+	immutable_slice []u8 = values[..]
+	mutable_slice []mut u8 = constcast!(immutable_slice)
+	mutable_slice[0] = 3
+
+	immutable_many *u8 = immutable_slice.ptr
+	mutable_many *mut u8 = constcast!(immutable_many)
+	mutable_many[1] = 4
+
+	number i32 = 5
+	immutable_single @i32 = &number
+	mutable_single @mut i32 = constcast!(immutable_single)
+	mutable_single^ = 6
+
+	maybe ?@i32 = immutable_single
+	mutable_maybe ?@mut i32 = constcast!(maybe)
+	if mutable_maybe |pointer| { pointer^ = 7 }
+
+	already_mutable []mut u8 = constcast!(mutable_slice)
+	if already_mutable[0] != 3 or already_mutable[1] != 4 or number != 7 { return 1 }
+	return 0
+}
+`
+	source_file := source.Source{path="constcast.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)
+	ir_module := lower.lower(&hir_module)
+	defer ir.destroy_module(&ir_module)
+
+	hir_casts, ir_casts := 0, 0
+	for expr in hir_module.exprs {
+		hir_casts += 1 if expr.kind == .Const_Cast else 0
+	}
+	for function in ir_module.functions {
+		for instruction in function.instructions {
+			ir_casts += 1 if instruction.op == .Const_Cast else 0
+		}
+	}
+	testing.expect_value(t, len(diagnostics.items), 0)
+	testing.expect_value(t, hir_casts, 5)
+	testing.expect_value(t, ir_casts, 5)
+
+	directory := "/tmp/brolang-test-constcast"
+	main_path := "/tmp/brolang-test-constcast/main.bro"
+	output := "/tmp/brolang-test-constcast-output"
+	_ = 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))
+	testing.expect_value(t, compiler_core.compile_package(directory, output), 0)
+	state := run_executable(output)
+	testing.expect_value(t, state.exit_code, 0)
+}
+
+@(test)
+invalid_constcasts_are_rejected :: proc(t: ^testing.T) {
+	text := `main func() void {
+	values [2]mut u8 = [1, 2]
+	_ = constcast!()
+	_ = constcast!(1, 2)
+	_ = constcast!(1)
+	_ = constcast!(values)
+}
+`
+	source_file := source.Source{path="invalid_constcast.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, bad_operand := false, false
+	for diagnostic in diagnostics.items {
+		bad_arity = bad_arity || strings.contains(diagnostic.message, "constcast! expects 1 argument")
+		bad_operand = bad_operand || strings.contains(diagnostic.message, "constcast! operand must be a pointer, optional pointer, or slice")
+	}
+	testing.expect(t, bad_arity && bad_operand)
+}
+
+@(test)
+immutable_allocations_can_be_freed_and_constcast_keeps_slice_bounds_checks :: proc(t: ^testing.T) {
+	free_text := `mem :: import "@std/mem"
+main func() i32 {
+	memory []mut u8 :: mem.alloc(u8, mem.c_allocator, 4) catch |_| { return 1 }
+	memory[0] = 42
+	immutable []u8 = memory
+	mem.free(mem.c_allocator, immutable)
+	empty []u8 = mem.empty(u8)
+	mem.free(mem.c_allocator, empty)
+	return 0
+}
+`
+	directory := "/tmp/brolang-test-immutable-free"
+	main_path := "/tmp/brolang-test-immutable-free/main.bro"
+	output := "/tmp/brolang-test-immutable-free-output"
+	_ = 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)free_text))
+	testing.expect_value(t, compiler_core.compile_package(
+		directory, output, nil, target.DEFAULT, cimport.Options{}, ".",
+	), 0)
+	state := run_executable(output)
+	testing.expect_value(t, state.exit_code, 0)
+
+	bounds_text := `main func() void {
+	values [2]mut u8 = [1, 2]
+	immutable []u8 = values[..]
+	mutable []mut u8 = constcast!(immutable)
+	_ = mutable[mutable.len]
+}
+`
+	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)bounds_text))
+	testing.expect_value(t, compiler_core.compile_package(directory, output), 0)
+	bounds_state, stdout, stderr, err := os2.process_exec(
+		os2.Process_Desc{command=[]string{output}}, context.allocator,
+	)
+	defer delete(stdout)
+	defer delete(stderr)
+	testing.expect(t, err == nil)
+	testing.expect(t, !bounds_state.success)
+	testing.expect(t, strings.contains(string(stderr), "index out of bounds"))
+}
+
 @(test)
 old_intrinsic_spellings_are_not_recognized :: proc(t: ^testing.T) {
 	text := `main func() void {