Mark labels in x64 write barrier code as local/alt_entry #119245
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Tagging subscribers to this area: @mangod9 |
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I am not sure if the failures are new to the PR or introduced by something in The symbols in my local build look okay ( The "rep retq" sequence also seems to be at the correct spot: |
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The x64 code in |
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I downloaded the failing payload from Helix and it has broken unwind info (it gets split on .alt_entry and creates bogus 0x00000000 unwind code): This is not happening for my local builds because I use Xcode 26 beta 6 which already fixed this particular bug (#119005). I'll try to workaround it. |
…ncorrect transformations by the ld64/ld-prime linkers
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@filipnavara it seems to me that the option 2 you've suggested would be a reasonable fix for now. |
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I'll look into it once I get back to my Mac. I think we just need a right place to put something like this: |
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I was going to put it in |
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Now that xcode 26 is released, can we rely on "upgrade to xcode 26" as the solution going forward? Or is this PR still necessary? |
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we don't control when AzDO/GitHub updates Xcode on the mac machines, and afaik the problem is with the new linker in Xcode 16+ so it presumably has the same problem in Xcode 26 |
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The originally reported problem affects all Xcodes with new linker, so presumably anything with Xcode 16+, including Xcode 26. It may or may not be triggered in a specific build depending on what layout and dead code elimination the linker decides to use. The added Unfortunately, there're numerous disjoint bugs in support for In summary, |
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Thanks! I'm interested in anything we can do to make this problem more manageable in the future. |
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I think we also need to at least backport the switch to ld_classic to servicing branches since we won't be able to stay on older macOS for very long |
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@janvorli Anything else here? |
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@agocke it looks good to me as is |
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/backport to release/10.0 |
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Started backporting to release/10.0: https://github.com/dotnet/runtime/actions/runs/18666782672 |
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/backport to release/9.0-staging |
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Started backporting to release/9.0-staging: https://github.com/dotnet/runtime/actions/runs/18666818024 |
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/backport to release/8.0-staging |
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Started backporting to release/8.0-staging: https://github.com/dotnet/runtime/actions/runs/18666828338 |
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@agocke backporting to "release/9.0-staging" failed, the patch most likely resulted in conflicts: $ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch
Applying: Mark labels in x64 write barrier code as local/alt_entry to prevent incorrect transformations by the ld64/ld-prime linkers
Applying: Fix the LEAF_END_MARKED macro for Apple platforms too
Applying: Mark all labels inside JIT_PatchedCode region as .alt_entry on Apple platforms
Using index info to reconstruct a base tree...
M src/coreclr/pal/inc/unixasmmacrosamd64.inc
M src/coreclr/pal/inc/unixasmmacrosarm64.inc
M src/coreclr/vm/arm64/patchedcode.S
Falling back to patching base and 3-way merge...
Auto-merging src/coreclr/pal/inc/unixasmmacrosamd64.inc
Auto-merging src/coreclr/pal/inc/unixasmmacrosarm64.inc
Auto-merging src/coreclr/vm/arm64/patchedcode.S
CONFLICT (content): Merge conflict in src/coreclr/vm/arm64/patchedcode.S
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0003 Mark all labels inside JIT_PatchedCode region as .alt_entry on Apple platforms
Error: The process '/usr/bin/git' failed with exit code 128Please backport manually! |
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@agocke backporting to "release/8.0-staging" failed, the patch most likely resulted in conflicts: $ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch
Applying: Mark labels in x64 write barrier code as local/alt_entry to prevent incorrect transformations by the ld64/ld-prime linkers
Applying: Fix the LEAF_END_MARKED macro for Apple platforms too
Applying: Mark all labels inside JIT_PatchedCode region as .alt_entry on Apple platforms
Using index info to reconstruct a base tree...
M src/coreclr/pal/inc/unixasmmacrosamd64.inc
M src/coreclr/pal/inc/unixasmmacrosarm64.inc
A src/coreclr/vm/amd64/patchedcode.S
A src/coreclr/vm/arm64/patchedcode.S
Falling back to patching base and 3-way merge...
Auto-merging src/coreclr/pal/inc/unixasmmacrosamd64.inc
Auto-merging src/coreclr/pal/inc/unixasmmacrosarm64.inc
CONFLICT (modify/delete): src/coreclr/vm/amd64/patchedcode.S deleted in HEAD and modified in Mark all labels inside JIT_PatchedCode region as .alt_entry on Apple platforms. Version Mark all labels inside JIT_PatchedCode region as .alt_entry on Apple platforms of src/coreclr/vm/amd64/patchedcode.S left in tree.
CONFLICT (modify/delete): src/coreclr/vm/arm64/patchedcode.S deleted in HEAD and modified in Mark all labels inside JIT_PatchedCode region as .alt_entry on Apple platforms. Version Mark all labels inside JIT_PatchedCode region as .alt_entry on Apple platforms of src/coreclr/vm/arm64/patchedcode.S left in tree.
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0003 Mark all labels inside JIT_PatchedCode region as .alt_entry on Apple platforms
Error: The process '/usr/bin/git' failed with exit code 128Please backport manually! |
…ry (#120923) Backport of #119245 to release/10.0 /cc @agocke @filipnavara ## Customer Impact - [ ] Customer reported - [X] Found internally [Select one or both of the boxes. Describe how this issue impacts customers, citing the expected and actual behaviors and scope of the issue. If customer-reported, provide the issue number.] ## Regression - [X] Yes - [ ] No This is a regression in the new Apple toolset. ## Testing Tested manually, and in macios CI. ## Risk Medium, product change coming somewhat late. However, this change has been running in the `main` branch for a couple weeks with no issue. --------- Co-authored-by: Filip Navara <[email protected]>
4 participants
Mark labels in x64 write barrier code as local/alt_entry to prevent incorrect transformations by the ld64/ld-prime linkers.
Contributes to #119174