# BUG: Wrong segment ordering for macOS using the non-LLVM ARM64 backend **URL:** \ **Category:** Help\ **Tags:** compiler\ **Created:** [November 26, 2025, 9:40am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221 "2025-11-26T09:40:54Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![joelreymont](https://ziggit.dev/user_avatar/ziggit.dev/joelreymont/32/3634_2.png) [@joelreymont](https://ziggit.dev/u/joelreymont)\ **Post date:** [November 26, 2025, 9:40am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/1 "2025-11-26T09:40:54Z")
When using the non-LLVM ARM64 backend (`-fno-llvm -fno-lld`) on macOS, binaries fail to run with: ```zig dyld: segment '__CONST_ZIG' vm address out of order ``` macOS dyld requires Mach-O segments to appear in ascending VM address order. The ZIG segments were all assigned the same rank (0xe) in `getSegmentRank()`, causing `segmentLessThan()` to fall back to alphabetical ordering: **Before (wrong - alphabetical):** ```zig __BSS_ZIG __CONST_ZIG __DATA_ZIG __TEXT_ZIG ``` **After (correct - VM address order):** ```zig __TEXT_ZIG __CONST_ZIG __DATA_ZIG __BSS_ZIG ``` ## Fix Assign each ZIG segment a unique rank in `getSegmentRank()`: ```zig if (mem.eql(u8, segname, "__TEXT_ZIG")) return 0xa; if (mem.eql(u8, segname, "__CONST_ZIG")) return 0xb; if (mem.eql(u8, segname, "__DATA_ZIG")) return 0xc; if (mem.eql(u8, segname, "__BSS_ZIG")) return 0xd; ``` Test ```zig $ zig build-exe -fno-llvm -fno-lld test.zig -femit-bin=test_bin $ ./test_bin $ echo $? 42 ``` I put the fix [here](https://github.com/joelreymont/zig/pull/1) since I can’t open issues or PRs in the Zig Github repo. ---
**Author:** ![joelreymont](https://ziggit.dev/user_avatar/ziggit.dev/joelreymont/32/3634_2.png) [@joelreymont](https://ziggit.dev/u/joelreymont)\ **Post date:** [November 26, 2025, 9:47am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/2 "2025-11-26T09:47:47Z")
How do I know? Before fix (upstream master) ```zig $ /Users/joel/Work/zig/master/out-llvm/bin/zig build-exe -fno-llvm -fno-lld /tmp/test_arm64_macos.zig -femit-bin=/tmp/test_unfixed $ /tmp/test_unfixed dyld[78487]: segment '__CONST_ZIG' vm address out of order in /private/tmp/test_unfixed dyld[78487]: segment '__CONST_ZIG' vm address out of order $ echo $? 134 $ otool -l /tmp/test_unfixed | grep "segname" | uniq segname __PAGEZERO segname __TEXT segname __DATA_CONST segname __DATA segname __BSS_ZIG segname __CONST_ZIG segname __DATA_ZIG segname __TEXT_ZIG segname __LINKEDIT ``` After fix ```zig $ /Users/joel/Work/zig/claude/zig-out/bin/zig build-exe -fno-llvm -fno-lld /tmp/test_arm64_macos.zig -femit-bin=/tmp/test_fixed $ /tmp/test_fixed $ echo $? 42 $ otool -l /tmp/test_fixed | grep "segname" | uniq segname __PAGEZERO segname __TEXT segname __DATA_CONST segname __DATA segname __TEXT_ZIG segname __CONST_ZIG segname __DATA_ZIG segname __BSS_ZIG segname __LINKEDIT ``` ---
**Author:** ![cryptocode](https://ziggit.dev/user_avatar/ziggit.dev/cryptocode/32/817_2.png) [@cryptocode](https://ziggit.dev/u/cryptocode)\ **Post date:** [November 26, 2025, 9:53am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/3 "2025-11-26T09:53:32Z")
Looks like there might be a tracking issue for this: [https://github.com/ziglang/zig/issues/25521](https://github.com/ziglang/zig/issues/25521) ---
**Author:** ![joelreymont](https://ziggit.dev/user_avatar/ziggit.dev/joelreymont/32/3634_2.png) [@joelreymont](https://ziggit.dev/u/joelreymont)\ **Post date:** [November 26, 2025, 9:54am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/4 "2025-11-26T09:54:51Z")
I’m on Apple Silicon. Could you update that issue with the link to my PR, please? I think the solution might be universal. ---
**Author:** ![cryptocode](https://ziggit.dev/user_avatar/ziggit.dev/cryptocode/32/817_2.png) [@cryptocode](https://ziggit.dev/u/cryptocode)\ **Post date:** [November 26, 2025, 10:08am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/5 "2025-11-26T10:08:38Z")
> [@joelreymont](#): > > Could you update that issue with the link to my PR, please? I won’t, sorry. You’ve been warned about breaking Zig’s strict AI policy on Zig’s github before, and this PR also reeks of LLM. ---
**Author:** ![tensorush](https://ziggit.dev/letter_avatar_proxy/v4/letter/t/6a8cbe/32.png) [@tensorush](https://ziggit.dev/u/tensorush)\ **Post date:** [November 26, 2025, 10:11am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/6 "2025-11-26T10:11:36Z")
---
**Author:** ![tensorush](https://ziggit.dev/letter_avatar_proxy/v4/letter/t/6a8cbe/32.png) [@tensorush](https://ziggit.dev/u/tensorush)\ **Post date:** [November 26, 2025, 10:19am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/7 "2025-11-26T10:19:44Z")
I’ve unlisted the topic since its only purpose is to promote a compiler bugfix from an untrusted contributor. ---
**Author:** ![joelreymont](https://ziggit.dev/user_avatar/ziggit.dev/joelreymont/32/3634_2.png) [@joelreymont](https://ziggit.dev/u/joelreymont)\ **Post date:** [November 26, 2025, 11:07am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/8 "2025-11-26T11:07:24Z")
I explained what the bug is. I gave a solution and tests for it. Not much else I can do. ---
**Author:** ![tensorush](https://ziggit.dev/letter_avatar_proxy/v4/letter/t/6a8cbe/32.png) [@tensorush](https://ziggit.dev/u/tensorush)\ **Post date:** [November 26, 2025, 11:08am UTC](https://ziggit.dev/t/bug-wrong-segment-ordering-for-macos-using-the-non-llvm-arm64-backend/13221/9 "2025-11-26T11:08:40Z")