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[ARM64] Fix CFG helper calling convention and simplify flow of call target address. #678

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Merged
kennykerr merged 1 commit into from
Jul 3, 2020
Merged

[ARM64] Fix CFG helper calling convention and simplify flow of call target address. #678

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22 changes: 9 additions & 13 deletions fast_fwd/arm64/thunks.asm
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Original file line number Diff line number Diff line change
Expand Up @@ -11,10 +11,9 @@
NESTED_ENTRY InvokeForwarder

; Save enregistered args
PROLOG_SAVE_REG_PAIR fp, lr, #-64!
PROLOG_SAVE_REG_PAIR x19, x20, #16
PROLOG_NOP stp x0, x1, [sp, #32]
PROLOG_NOP stp x2, x3, [sp, #48]
PROLOG_SAVE_REG_PAIR fp, lr, #-48!
PROLOG_NOP stp x0, x1, [sp, #16]
PROLOG_NOP stp x2, x3, [sp, #32]

; Replace forwarder abi with owner abi
ldr x1, [x0, #8]
Expand All @@ -26,23 +25,20 @@

; Get method address from owner abi vtable
ldr x0, [x1]
ldr x19, [x0, x12, lsl #3]
mov x0, x19
ldr x15, [x0, x12, lsl #3]

; Verify indirect call target
adrp x12, __guard_check_icall_fptr
ldr x12, [x12, __guard_check_icall_fptr]
blr x12

; Restore method address, return address, and args
mov x12, x19
EPILOG_NOP ldp x2, x3, [sp, #48]
EPILOG_NOP ldp x0, x1, [sp, #32]
EPILOG_RESTORE_REG_PAIR x19, x20, #16
EPILOG_RESTORE_REG_PAIR fp, lr, #64!
; Restore return address, and args
EPILOG_NOP ldp x2, x3, [sp, #32]
EPILOG_NOP ldp x0, x1, [sp, #16]
EPILOG_RESTORE_REG_PAIR fp, lr, #48!

; Jump to method
EPILOG_NOP br x12
EPILOG_NOP br x15

NESTED_END InvokeForwarder

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