Revert "Reland [AArch64][MachineOutliner] Return address signing for outlined functions"
This reverts commit cec2d5c174.
Reverting because this is still creating outlined functions with return
address signing instructions with mismatches SP values. For example:
int *volatile v;
void foo(int x) {
int a[x];
v = &a[0];
v = &a[0];
v = &a[0];
v = &a[0];
v = &a[0];
v = &a[0];
}
void bar(int x) {
int a[x];
v = 0;
v = &a[0];
v = &a[0];
v = &a[0];
v = &a[0];
v = &a[0];
}
This generates these two outlined functions, both of which modify SP
between the paciasp and retaa instructions:
$ clang --target=aarch64-arm-none-eabi -march=armv8.3-a -c test2.c -o - -S -Oz -mbranch-protection=pac-ret+leaf
...
OUTLINED_FUNCTION_0: // @OUTLINED_FUNCTION_0
.cfi_sections .debug_frame
.cfi_startproc
// %bb.0:
paciasp
.cfi_negate_ra_state
mov w8, w0
lsl x8, x8, #2
add x8, x8, #15 // =15
mov x9, sp
and x8, x8, #0x7fffffff0
sub x8, x9, x8
mov x29, sp
mov sp, x8
adrp x9, v
retaa
...
OUTLINED_FUNCTION_1: // @OUTLINED_FUNCTION_1
.cfi_startproc
// %bb.0:
paciasp
.cfi_negate_ra_state
str x8, [x9, :lo12:v]
str x8, [x9, :lo12:v]
str x8, [x9, :lo12:v]
str x8, [x9, :lo12:v]
str x8, [x9, :lo12:v]
mov sp, x29
retaa
6ae3d310bd