AArch64: correct preserve_most and preserve_all on Windows (#166436)
#11751
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…166436) This fixes register information handling for the `preserve_most` and `preserve_all` calling conventions on Windows ARM64. The root issue was cascading `if` statements whose behavior depended on their order. This patch makes the minimal, tactical change needed for Swift’s two calling conventions, unblocking current work. A broader refactor to remove the ordering dependency is still desired and will follow in a subsequent PR. (cherry picked from commit 8cd2244)
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@swift-ci please test |
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@swift-ci please test Windows platform |
Correct a typo in the triple that is used for the test. Because the OS was not recognised, it would fall to the non-Windows code generation. (cherry picked from commit 66f52ca)
When lowering code for Windows, we might be using a non-standard calling convention (e.g. `preserve_most`). In such a case, we might be spilling registers which are unexpected (i.e. x9-x15). Use the ARM64EC opcodes to indicate such spills. This adds support for the handling for these spills but is insufficient on its own. The encoded results are incorrect due to the expectation that the pair wise spills are always 16-byte aligned which we currently do not enforce. Fixing that is beyond the scope of emitting the SEH directives for the spill. (cherry picked from commit 77b9301)
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This fixes register information handling for the
preserve_mostandpreserve_allcalling conventions on Windows ARM64.The root issue was cascading
ifstatements whose behavior depended on their order. This patch makes the minimal, tactical change needed for Swift’s two calling conventions, unblocking current work. A broader refactor to remove the ordering dependency is still desired and will follow in a subsequent PR.(cherry picked from commit 8cd2244)