winch(aarch64): Sync SP with SSP when claiming stack#10263
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alexcrichton merged 2 commits intobytecodealliance:mainfrom Feb 26, 2025
Merged
winch(aarch64): Sync SP with SSP when claiming stack#10263alexcrichton merged 2 commits intobytecodealliance:mainfrom
alexcrichton merged 2 commits intobytecodealliance:mainfrom
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The diff is considerably large, since this change touches all of the disassembly tests for aarch64. The relevant changes are in the first commit 97d7f74 |
This commit is a follow-up to bytecodealliance#10146 and represents another step toward fixing the remaining issues discovered through spec tests in the same vein as bytecodealliance#10201 Specifically, this commit ensures that the stack pointer is always in sync with the shadow stack pointer. The previous approach was lossy because it only performed the sync when reserving stack space. While this approach worked in some cases, it failed to account for situations where the shadow stack pointer might be adjusted and aligned for calls. As a result, the stack pointer could become unaligned when claiming stack space, leading to issues at call sites. It is possible to avoid the unconditional move and perform it only when alignment is needed, i.e., at call sites and when the real stack pointer is unaligned. However, as of now, the simplest solution is to always perform the sync, which integrates best with the current infrastructure.
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This commit is a follow-up to
#10146 and represents another step toward fixing the remaining issues discovered through spec tests in the same vein as #10201
Specifically, this commit ensures that the stack pointer is always in sync with the shadow stack pointer. The previous approach was lossy because it only performed the sync when reserving stack space. While this approach worked in some cases, it failed to account for situations where the shadow stack pointer might be adjusted and aligned for calls. As a result, the stack pointer could become unaligned when claiming stack space, leading to issues at call sites.
It is possible to avoid the unconditional move and perform it only when alignment is needed, i.e., at call sites and when the real stack pointer is unaligned. However, as of now, the simplest solution is to always perform the sync, which integrates best with the current infrastructure.