zig/test/behavior/align.zig
2024-03-30 20:50:48 -04:00

698 lines
22 KiB
Zig

const std = @import("std");
const expect = std.testing.expect;
const builtin = @import("builtin");
const native_arch = builtin.target.cpu.arch;
const assert = std.debug.assert;
var foo: u8 align(4) = 100;
test "global variable alignment" {
comptime assert(@typeInfo(@TypeOf(&foo)).Pointer.alignment == 4);
comptime assert(@TypeOf(&foo) == *align(4) u8);
{
const slice = @as(*align(4) [1]u8, &foo)[0..];
comptime assert(@TypeOf(slice) == *align(4) [1]u8);
}
}
test "large alignment of local constant" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // flaky
const x: f32 align(128) = 12.34;
try std.testing.expect(@intFromPtr(&x) % 128 == 0);
}
test "slicing array of length 1 can not assume runtime index is always zero" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // flaky
var runtime_index: usize = 1;
_ = &runtime_index;
const slice = @as(*align(4) [1]u8, &foo)[runtime_index..];
try expect(@TypeOf(slice) == []u8);
try expect(slice.len == 0);
try expect(@as(u2, @truncate(@intFromPtr(slice.ptr) - 1)) == 0);
}
test "default alignment allows unspecified in type syntax" {
try expect(*u32 == *align(@alignOf(u32)) u32);
}
test "implicitly decreasing pointer alignment" {
const a: u32 align(4) = 3;
const b: u32 align(8) = 4;
try expect(addUnaligned(&a, &b) == 7);
}
fn addUnaligned(a: *align(1) const u32, b: *align(1) const u32) u32 {
return a.* + b.*;
}
test "@alignCast pointers" {
var x: u32 align(4) = 1;
expectsOnly1(&x);
try expect(x == 2);
}
fn expectsOnly1(x: *align(1) u32) void {
expects4(@alignCast(x));
}
fn expects4(x: *align(4) u32) void {
x.* += 1;
}
test "alignment of struct with pointer has same alignment as usize" {
try expect(@alignOf(struct {
a: i32,
b: *i32,
}) == @alignOf(usize));
}
test "alignment and size of structs with 128-bit fields" {
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
const A = struct {
x: u128,
};
const B = extern struct {
x: u128,
y: u8,
};
const expected = switch (builtin.cpu.arch) {
.arm,
.armeb,
.thumb,
.thumbeb,
.hexagon,
.mips,
.mipsel,
.powerpc,
.powerpcle,
.r600,
.amdgcn,
.riscv32,
.sparc,
.sparcel,
.s390x,
.lanai,
.wasm32,
.wasm64,
=> .{
.a_align = 8,
.a_size = 16,
.b_align = 16,
.b_size = 32,
.u128_align = 8,
.u128_size = 16,
.u129_align = 8,
.u129_size = 24,
},
.x86 => if (builtin.object_format == .c) .{
.a_align = 16,
.a_size = 16,
.b_align = 16,
.b_size = 32,
.u128_align = 16,
.u128_size = 16,
.u129_align = 16,
.u129_size = 32,
} else switch (builtin.os.tag) {
.windows => .{
.a_align = 8,
.a_size = 16,
.b_align = 16,
.b_size = 32,
.u128_align = 8,
.u128_size = 16,
.u129_align = 8,
.u129_size = 24,
},
else => .{
.a_align = 4,
.a_size = 16,
.b_align = 16,
.b_size = 32,
.u128_align = 4,
.u128_size = 16,
.u129_align = 4,
.u129_size = 20,
},
},
.mips64,
.mips64el,
.powerpc64,
.powerpc64le,
.sparc64,
.x86_64,
=> switch (builtin.object_format) {
.c => .{
.a_align = 16,
.a_size = 16,
.b_align = 16,
.b_size = 32,
.u128_align = 16,
.u128_size = 16,
.u129_align = 16,
.u129_size = 32,
},
else => .{
.a_align = 8,
.a_size = 16,
.b_align = 16,
.b_size = 32,
.u128_align = 8,
.u128_size = 16,
.u129_align = 8,
.u129_size = 24,
},
},
.aarch64,
.aarch64_be,
.aarch64_32,
.riscv64,
.bpfel,
.bpfeb,
.nvptx,
.nvptx64,
=> .{
.a_align = 16,
.a_size = 16,
.b_align = 16,
.b_size = 32,
.u128_align = 16,
.u128_size = 16,
.u129_align = 16,
.u129_size = 32,
},
else => return error.SkipZigTest,
};
const min_struct_align = if (builtin.zig_backend == .stage2_c) 16 else 0;
comptime {
assert(@alignOf(A) == @max(expected.a_align, min_struct_align));
assert(@sizeOf(A) == expected.a_size);
assert(@alignOf(B) == @max(expected.b_align, min_struct_align));
assert(@sizeOf(B) == expected.b_size);
assert(@alignOf(u128) == expected.u128_align);
assert(@sizeOf(u128) == expected.u128_size);
assert(@alignOf(u129) == expected.u129_align);
assert(@sizeOf(u129) == expected.u129_size);
}
}
test "alignstack" {
try expect(fnWithAlignedStack() == 1234);
}
fn fnWithAlignedStack() i32 {
@setAlignStack(256);
return 1234;
}
test "implicitly decreasing slice alignment" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
const a: u32 align(4) = 3;
const b: u32 align(8) = 4;
try expect(addUnalignedSlice(@as(*const [1]u32, &a)[0..], @as(*const [1]u32, &b)[0..]) == 7);
}
fn addUnalignedSlice(a: []align(1) const u32, b: []align(1) const u32) u32 {
return a[0] + b[0];
}
test "specifying alignment allows pointer cast" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
try testBytesAlign(0x33);
}
fn testBytesAlign(b: u8) !void {
var bytes align(4) = [_]u8{ b, b, b, b };
const ptr = @as(*u32, @ptrCast(&bytes[0]));
try expect(ptr.* == 0x33333333);
}
test "@alignCast slices" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
var array align(4) = [_]u32{ 1, 1 };
const slice = array[0..];
sliceExpectsOnly1(slice);
try expect(slice[0] == 2);
}
fn sliceExpectsOnly1(slice: []align(1) u32) void {
sliceExpects4(@alignCast(slice));
}
fn sliceExpects4(slice: []align(4) u32) void {
slice[0] += 1;
}
test "return error union with 128-bit integer" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
try expect(3 == try give());
}
fn give() anyerror!u128 {
return 3;
}
test "page aligned array on stack" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
if (builtin.cpu.arch == .aarch64 and builtin.os.tag == .windows) {
// https://github.com/ziglang/zig/issues/13679
return error.SkipZigTest;
}
// Large alignment value to make it hard to accidentally pass.
var array align(0x1000) = [_]u8{ 1, 2, 3, 4, 5, 6, 7, 8 };
var number1: u8 align(16) = 42;
var number2: u8 align(16) = 43;
try expect(@intFromPtr(&array[0]) & 0xFFF == 0);
try expect(array[3] == 4);
try expect(@as(u4, @truncate(@intFromPtr(&number1))) == 0);
try expect(@as(u4, @truncate(@intFromPtr(&number2))) == 0);
try expect(number1 == 42);
try expect(number2 == 43);
}
test "function alignment" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
// function alignment is a compile error on wasm32/wasm64
if (native_arch == .wasm32 or native_arch == .wasm64) return error.SkipZigTest;
const S = struct {
fn alignExpr() align(@sizeOf(usize) * 2) i32 {
return 1234;
}
fn align1() align(1) void {}
fn align4() align(4) void {}
};
try expect(S.alignExpr() == 1234);
try expect(@TypeOf(S.alignExpr) == fn () i32);
try expect(@TypeOf(&S.alignExpr) == *align(@sizeOf(usize) * 2) const fn () i32);
S.align1();
try expect(@TypeOf(S.align1) == fn () void);
try expect(@TypeOf(&S.align1) == *align(1) const fn () void);
S.align4();
try expect(@TypeOf(S.align4) == fn () void);
try expect(@TypeOf(&S.align4) == *align(4) const fn () void);
}
test "implicitly decreasing fn alignment" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
// function alignment is a compile error on wasm32/wasm64
if (native_arch == .wasm32 or native_arch == .wasm64) return error.SkipZigTest;
try testImplicitlyDecreaseFnAlign(alignedSmall, 1234);
try testImplicitlyDecreaseFnAlign(alignedBig, 5678);
}
fn testImplicitlyDecreaseFnAlign(ptr: *align(1) const fn () i32, answer: i32) !void {
try expect(ptr() == answer);
}
fn alignedSmall() align(8) i32 {
return 1234;
}
fn alignedBig() align(16) i32 {
return 5678;
}
test "@alignCast functions" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
// function alignment is a compile error on wasm32/wasm64
if (native_arch == .wasm32 or native_arch == .wasm64) return error.SkipZigTest;
if (native_arch == .thumb) return error.SkipZigTest;
try expect(fnExpectsOnly1(simple4) == 0x19);
}
fn fnExpectsOnly1(ptr: *align(1) const fn () i32) i32 {
return fnExpects4(@alignCast(ptr));
}
fn fnExpects4(ptr: *align(4) const fn () i32) i32 {
return ptr();
}
fn simple4() align(4) i32 {
return 0x19;
}
test "function align expression depends on generic parameter" {
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
// function alignment is a compile error on wasm32/wasm64
if (native_arch == .wasm32 or native_arch == .wasm64) return error.SkipZigTest;
if (native_arch == .thumb) return error.SkipZigTest;
const S = struct {
fn doTheTest() !void {
try expect(foobar(1) == 2);
try expect(foobar(4) == 5);
try expect(foobar(8) == 9);
}
fn foobar(comptime align_bytes: u8) align(align_bytes) u8 {
return align_bytes + 1;
}
};
try S.doTheTest();
try comptime S.doTheTest();
}
test "function callconv expression depends on generic parameter" {
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
const S = struct {
fn doTheTest() !void {
try expect(foobar(.C, 1) == 2);
try expect(foobar(.Unspecified, 2) == 3);
}
fn foobar(comptime cc: std.builtin.CallingConvention, arg: u8) callconv(cc) u8 {
return arg + 1;
}
};
try S.doTheTest();
try comptime S.doTheTest();
}
test "runtime-known array index has best alignment possible" {
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
// take full advantage of over-alignment
var array align(4) = [_]u8{ 1, 2, 3, 4 };
comptime assert(@TypeOf(&array[0]) == *align(4) u8);
comptime assert(@TypeOf(&array[1]) == *u8);
comptime assert(@TypeOf(&array[2]) == *align(2) u8);
comptime assert(@TypeOf(&array[3]) == *u8);
// because align is too small but we still figure out to use 2
var bigger align(2) = [_]u64{ 1, 2, 3, 4 };
comptime assert(@TypeOf(&bigger[0]) == *align(2) u64);
comptime assert(@TypeOf(&bigger[1]) == *align(2) u64);
comptime assert(@TypeOf(&bigger[2]) == *align(2) u64);
comptime assert(@TypeOf(&bigger[3]) == *align(2) u64);
// because pointer is align 2 and u32 align % 2 == 0 we can assume align 2
var smaller align(2) = [_]u32{ 1, 2, 3, 4 };
var runtime_zero: usize = 0;
_ = &runtime_zero;
comptime assert(@TypeOf(smaller[runtime_zero..]) == []align(2) u32);
comptime assert(@TypeOf(smaller[runtime_zero..].ptr) == [*]align(2) u32);
try testIndex(smaller[runtime_zero..].ptr, 0, *align(2) u32);
try testIndex(smaller[runtime_zero..].ptr, 1, *align(2) u32);
try testIndex(smaller[runtime_zero..].ptr, 2, *align(2) u32);
try testIndex(smaller[runtime_zero..].ptr, 3, *align(2) u32);
// has to use ABI alignment because index known at runtime only
try testIndex2(&array, 0, *u8);
try testIndex2(&array, 1, *u8);
try testIndex2(&array, 2, *u8);
try testIndex2(&array, 3, *u8);
}
fn testIndex(smaller: [*]align(2) u32, index: usize, comptime T: type) !void {
comptime assert(@TypeOf(&smaller[index]) == T);
}
fn testIndex2(ptr: [*]align(4) u8, index: usize, comptime T: type) !void {
comptime assert(@TypeOf(&ptr[index]) == T);
}
test "alignment of function with c calling convention" {
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
const a = @alignOf(@TypeOf(nothing));
var runtime_nothing = &nothing;
_ = &runtime_nothing;
const casted1: *align(a) const u8 = @ptrCast(runtime_nothing);
const casted2: *const fn () callconv(.C) void = @ptrCast(casted1);
casted2();
}
fn nothing() callconv(.C) void {}
const DefaultAligned = struct {
nevermind: u32,
badguy: i128,
};
test "read 128-bit field from default aligned struct in stack memory" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
var default_aligned = DefaultAligned{
.nevermind = 1,
.badguy = 12,
};
_ = &default_aligned;
try expect(12 == default_aligned.badguy);
}
var default_aligned_global = DefaultAligned{
.nevermind = 1,
.badguy = 12,
};
test "read 128-bit field from default aligned struct in global memory" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
try expect(12 == default_aligned_global.badguy);
}
test "struct field explicit alignment" {
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // flaky
const S = struct {
const Node = struct {
next: *Node,
massive_byte: u8 align(64),
};
};
var node: S.Node = undefined;
node.massive_byte = 100;
try expect(node.massive_byte == 100);
comptime assert(@TypeOf(&node.massive_byte) == *align(64) u8);
try expect(@intFromPtr(&node.massive_byte) % 64 == 0);
}
test "align(@alignOf(T)) T does not force resolution of T" {
if (true) return error.SkipZigTest; // TODO
const S = struct {
const A = struct {
a: *align(@alignOf(A)) A,
};
fn doTheTest() void {
suspend {
resume @frame();
}
_ = bar(@Frame(doTheTest));
}
fn bar(comptime T: type) *align(@alignOf(T)) T {
ok = true;
return undefined;
}
var ok = false;
};
_ = async S.doTheTest();
try expect(S.ok);
}
test "align(N) on functions" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_c) {
// https://github.com/ziglang/zig/issues/16845
return error.SkipZigTest;
}
if (builtin.zig_backend == .stage2_c and builtin.os.tag == .windows) {
// This is not supported on MSVC.
return error.SkipZigTest;
}
// function alignment is a compile error on wasm32/wasm64
if (native_arch == .wasm32 or native_arch == .wasm64) return error.SkipZigTest;
if (native_arch == .thumb) return error.SkipZigTest;
try expect((@intFromPtr(&overaligned_fn) & (0x1000 - 1)) == 0);
}
fn overaligned_fn() align(0x1000) i32 {
return 42;
}
test "comptime alloc alignment" {
// TODO: it's impossible to test this in Zig today, since comptime vars do not have runtime addresses.
if (true) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // flaky
if (builtin.zig_backend == .stage2_llvm and builtin.target.cpu.arch == .x86) {
// https://github.com/ziglang/zig/issues/18034
return error.SkipZigTest;
}
comptime var bytes1 = [_]u8{0};
_ = &bytes1;
comptime var bytes2 align(256) = [_]u8{0};
const bytes2_addr = @intFromPtr(&bytes2);
try expect(bytes2_addr & 0xff == 0);
}
test "@alignCast null" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
var ptr: ?*anyopaque = null;
_ = &ptr;
const aligned: ?*anyopaque = @alignCast(ptr);
try expect(aligned == null);
}
test "alignment of slice element" {
const a: []align(1024) const u8 = undefined;
try expect(@TypeOf(&a[0]) == *align(1024) const u8);
}
test "sub-aligned pointer field access" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest;
// Originally reported at https://github.com/ziglang/zig/issues/14904
const Header = extern struct {
tag: u32,
bytes_len: u32,
};
var buf: [9]u8 align(4) = .{ 1, 2, 3, 4, 5, 6, 7, 8, 9 };
const ptr: *align(1) Header = @ptrCast(buf[1..][0..8]);
const x = ptr.bytes_len;
switch (builtin.cpu.arch.endian()) {
.big => try expect(x == 0x06070809),
.little => try expect(x == 0x09080706),
}
}
test "alignment of zero-bit types is respected" {
if (true) return error.SkipZigTest; // TODO
const S = struct { arr: [0]usize = .{} };
comptime assert(@alignOf(void) == 1);
comptime assert(@alignOf(u0) == 1);
comptime assert(@alignOf([0]usize) == @alignOf(usize));
comptime assert(@alignOf(S) == @alignOf(usize));
var s: S = .{};
var v32: void align(32) = {};
var x32: u0 align(32) = 0;
var s32: S align(32) = .{};
var zero: usize = 0;
_ = &zero;
try expect(@intFromPtr(&s) % @alignOf(usize) == 0);
try expect(@intFromPtr(&s.arr) % @alignOf(usize) == 0);
try expect(@intFromPtr(s.arr[zero..zero].ptr) % @alignOf(usize) == 0);
try expect(@intFromPtr(&v32) % 32 == 0);
try expect(@intFromPtr(&x32) % 32 == 0);
try expect(@intFromPtr(&s32) % 32 == 0);
try expect(@intFromPtr(&s32.arr) % 32 == 0);
try expect(@intFromPtr(s32.arr[zero..zero].ptr) % 32 == 0);
}
test "zero-bit fields in extern struct pad fields appropriately" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
const S = extern struct {
x: u8,
a: [0]u16 = .{},
y: u8,
};
// `a` should give `S` alignment 2, and pad the `arr` field.
comptime assert(@alignOf(S) == 2);
comptime assert(@sizeOf(S) == 4);
comptime assert(@offsetOf(S, "x") == 0);
comptime assert(@offsetOf(S, "a") == 2);
comptime assert(@offsetOf(S, "y") == 2);
var s: S = .{ .x = 100, .y = 200 };
try expect(@intFromPtr(&s) % 2 == 0);
try expect(@intFromPtr(&s.y) - @intFromPtr(&s.x) == 2);
try expect(@intFromPtr(&s.y) == @intFromPtr(&s.a));
try expect(@as(*S, @fieldParentPtr("a", &s.a)) == &s);
}