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[llvm][Support] Add ARM64e support for split stacks #139964

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[llvm][Support] Add ARM64e support for split stacks #139964

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11 changes: 11 additions & 0 deletions llvm/lib/Support/ProgramStack.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,9 @@ __asm__ (
".p2align 2\n\t"
"_ZN4llvm17runOnNewStackImplEPvPFvS0_ES0_:\n\t"
".cfi_startproc\n\t"
#if __arm64e__
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@ahmedbougacha ahmedbougacha May 22, 2025

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Perhaps:
__has_feature(ptrauth_returns)
here and around the retab

"pacibsp\n\t" // sign x30 using sp
#endif
"mov x16, sp\n\t"
"sub x0, x0, #0x20\n\t" // subtract space from stack
"stp xzr, x16, [x0, #0x00]\n\t" // save old sp
Expand All @@ -81,12 +84,20 @@ __asm__ (
".cfi_offset w29, -16\n\t" // fp

"mov x0, x2\n\t" // Ctx is the only argument
#if __arm64e__
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@ahmedbougacha ahmedbougacha May 22, 2025

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And here:
__has_feature(ptrauth_calls)

"blraaz x1\n\t" // authenticate x1 then call Fn
#else
"blr x1\n\t" // call Fn
#endif

"ldp x29, x30, [sp, #0x10]\n\t" // restore fp, lr
"ldp xzr, x16, [sp, #0x00]\n\t" // load old sp
"mov sp, x16\n\t"
#if __arm64e__
"retab\n\t" // authenticate x30 then return
#else
"ret\n\t"
#endif
".cfi_endproc"
);
#endif
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