(0.54) Use AArch64 IPC register for indirect branches in JIT runtime #22342
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The macro `BRANCH_VIA_VMTHREAD` in the JIT runtime uses the `x8` register to perform an indirect branch to an arbitrary function. However, this macro may be used in contexts where it is not safe to clobber `x8`. Use the conventional AArch64 ABI register `x16` for this purpose instead. The JIT does not register assign `x16` so there are no conflicts. Signed-off-by: Daryl Maier <[email protected]>
pshipton
approved these changes
Jul 31, 2025
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The macro
BRANCH_VIA_VMTHREADin the JIT runtime uses thex8register to perform an indirect branch to an arbitrary function. However, this macro may be used in contexts where it is not safe to clobberx8.Use the conventional AArch64 ABI register
x16for this purpose instead. The JIT does not register assignx16so there are no conflicts.Fixes: #21824
Backport #22339