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regression: compiling a x86-windows app with threads with a 64-bit compiler #19619

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regression: compiling a x86-windows app with threads with a 64-bit compiler#19619
Labels
arch-x8632-bit x86bugObserved behavior contradicts documented or intended behaviorstandard libraryThis issue involves writing Zig code for the standard library.
Milestone
0.13.0

Description

@llogick
llogick
opened on Apr 11, 2024

Zig Version

0.12.0-dev.3634+3d1652070

Steps to Reproduce and Observed Behavior

> zig build -freference-trace --summary all -Dtarget=x86-windows
install
└─ install zls
   └─ zig build-exe zls Debug x86-windows 2 errors
/home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:39: error: @fieldParentPtr increases pointer alignment
            const closure: *@This() = @fieldParentPtr("run_node", run_node);
                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:39: note: '*align(4) Thread.Pool.spawn__anon_10636.Closure' has alignment '4'
/home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:39: note: '*Thread.Pool.spawn__anon_10636.Closure' has alignment '8'
/home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:39: note: use @alignCast to assert pointer alignment
referenced by:
    spawn__anon_10636.Closure: /home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:88:58
    runFn: /home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:29
/home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:39: error: @fieldParentPtr increases pointer alignment
            const closure: *@This() = @fieldParentPtr("run_node", run_node);
                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:39: note: '*align(4) Thread.Pool.spawn__anon_10640.Closure' has alignment '4'
/home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:39: note: '*Thread.Pool.spawn__anon_10640.Closure' has alignment '8'
/home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:39: note: use @alignCast to assert pointer alignment
referenced by:
    spawn__anon_10640.Closure: /home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:88:58
    runFn: /home/rad/lab/zig/build/stage4/lib/zig/std/Thread/Pool.zig:92:29
error: the following command failed with 2 compilation errors:
/home/rad/lab/zig/build/stage4/bin/zig build-exe -freference-trace=256 -ODebug -target x86-windows -mcpu baseline --dep exe_options --dep tracy --dep known-folders --dep zls -Mroot=/home/rad/lab/zls/npdm/src/main.zig -Mexe_options=/home/rad/lab/zls/npdm/zig-cache/c/cdb97d55e32f50fc9169d1029ec866c5/options.zig -ODebug -target x86-windows -mcpu baseline --dep options -Mtracy=/home/rad/lab/zls/npdm/src/tracy.zig -Mknown-folders=/home/rad/.cache/zig/p/12201314cffeb40c5e4e3da166217d2c74628c74486414aaf97422bcd2279915b9fd/known-folders.zig --dep known-folders --dep diffz --dep tracy --dep build_options --dep version_data -Mzls=/home/rad/lab/zls/npdm/src/zls.zig -Moptions=/home/rad/lab/zls/npdm/zig-cache/c/afa1e7d8563bc1d60b4c78e42a5d2105/options.zig -Mdiffz=/home/rad/.cache/zig/p/12200d71e4b7029ea56a429e24260c6c0e85a3069b0d4ba85eace21a0fd75910aa64/DiffMatchPatch.zig -Mbuild_options=/home/rad/lab/zls/npdm/zig-cache/c/657d1a35550280ee156902394a1ec894/options.zig -Mversion_data=/home/rad/lab/zls/npdm/zig-cache/o/e184a1362fefa6803c3727e5faace999/version_data_master_19824.zig --cache-dir /home/rad/lab/zls/npdm/zig-cache --global-cache-dir /home/rad/.cache/zig --name zls --listen=-

Expected Behavior

It used to work afaik.

Activity

  1. llogick
    added
    bugObserved behavior contradicts documented or intended behavior
    on Apr 11, 2024

  2. rohlem commented on Apr 11, 2024

    @rohlem
    rohlem
    on Apr 11, 2024
    Contributor

    If the pointer logic is sound (which it presumably is), the code now needs to assert the required alignment via @alignCast.
    (EDIT: Meaning we forgot to update std in this place.)

  3. Vexu commented on Apr 12, 2024

    @Vexu
    Vexu
    on Apr 12, 2024
    Member

    This was an intentional change in #19470

  4. nektro commented on Apr 12, 2024

    @nektro
    nektro
    on Apr 12, 2024
    Contributor

    those errors and notes are all in the standard library.

    my confusion is how is a *Thread.Pool.spawn__anon_10636.Closure have an alignment of 8 on 32bit ?

  5. Vexu
    added
    standard libraryThis issue involves writing Zig code for the standard library.
    on Apr 12, 2024
  6. Vexu
    added this to the 0.13.0 milestone on Apr 12, 2024
  7. Vexu
    added
    arch-x8632-bit x86
    on Apr 12, 2024

  8. techatrix commented on Apr 12, 2024

    @techatrix
    techatrix
    on Apr 12, 2024
    Contributor

    Here is a code snippet that triggers the compile error:

    const std = @import("std");

fn getOptional() ?u64 {
    return 0;
}

fn func(_: u64) void {}

pub fn main() !void {
    var thread_pool: std.Thread.Pool = undefined;
    thread_pool.init(.{ .allocator = std.heap.page_allocator });
    defer thread_pool.deinit();

    if (getOptional()) |value| {
        try thread_pool.spawn(func, .{value});
    }
}

    This doesn't happen if value is just const value: u64 = 0;

  9. llogick
    added a commit that references this issue on Apr 13, 2024

    Disable the `x86-windows` target

    d416476
  10. llogick
    closed this as completedon May 4, 2024
  11. andrewrk
    modified the milestones: 0.14.0, 0.13.0 on May 22, 2024
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