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1b672e41c5
This changeset fixes the handling of alignment in several places. The new rules are: * `@alignOf(T)` where `T` is a runtime zero-bit type is at least 1, maybe greater. * Zero-bit fields in `extern` structs *do* force alignment, potentially offsetting following fields. * Zero-bit fields *do* have addresses within structs which can be observed and are consistent with `@offsetOf`. These are not necessarily all implemented correctly yet (see disabled test), but this commit fixes all regressions compared to master, and makes one new test pass.
38 lines
1.1 KiB
Zig
38 lines
1.1 KiB
Zig
const std = @import("std");
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const expect = std.testing.expect;
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const builtin = @import("builtin");
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const native_arch = builtin.target.cpu.arch;
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const maxInt = std.math.maxInt;
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const Foo = struct {
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x: u32,
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y: u32,
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z: u32,
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};
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test "@alignOf(T) before referencing T" {
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try comptime expect(@alignOf(Foo) != maxInt(usize));
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if (native_arch == .x86_64) {
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try comptime expect(@alignOf(Foo) == 4);
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}
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}
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test "comparison of @alignOf(T) against zero" {
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const T = struct { x: u32 };
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try expect(!(@alignOf(T) == 0));
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try expect(@alignOf(T) != 0);
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try expect(!(@alignOf(T) < 0));
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try expect(!(@alignOf(T) <= 0));
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try expect(@alignOf(T) > 0);
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try expect(@alignOf(T) >= 0);
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}
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test "correct alignment for elements and slices of aligned array" {
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var buf: [1024]u8 align(64) = undefined;
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var start: usize = 1;
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var end: usize = undefined;
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try expect(@alignOf(@TypeOf(buf[start..end])) == @alignOf(*u8));
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try expect(@alignOf(@TypeOf(&buf[start..end])) == @alignOf(*u8));
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try expect(@alignOf(@TypeOf(&buf[start])) == @alignOf(*u8));
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}
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