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[BOLT][AArch64] Reduce the number of ADR relaxations (#111577)
If ADR instruction references the same function, we can skip relaxation even if the function is split but ADR is in the main fragment.
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## Check that llvm-bolt will not unnecessarily relax ADR instruction. | ||
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# RUN: llvm-mc -filetype=obj -triple aarch64-unknown-unknown %s -o %t.o | ||
# RUN: %clang %cflags %t.o -o %t.exe -Wl,-q -static | ||
# RUN: llvm-bolt %t.exe -o %t.bolt --split-functions --split-strategy=random2 | ||
# RUN: llvm-objdump -d --disassemble-symbols=_start %t.bolt | FileCheck %s | ||
# RUN: llvm-objdump -d --disassemble-symbols=foo.cold.0 %t.bolt \ | ||
# RUN: | FileCheck --check-prefix=CHECK-FOO %s | ||
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## ADR below references its containing function that is split. But ADR is always | ||
## in the main fragment, thus there is no need to relax it. | ||
.text | ||
.globl _start | ||
.type _start, %function | ||
_start: | ||
# CHECK: <_start>: | ||
.cfi_startproc | ||
adr x1, _start | ||
# CHECK-NOT: adrp | ||
# CHECK: adr | ||
cmp x1, x11 | ||
b.hi .L1 | ||
mov x0, #0x0 | ||
.L1: | ||
ret x30 | ||
.cfi_endproc | ||
.size _start, .-_start | ||
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## In foo, ADR is in the split fragment but references the main one. Thus, it | ||
## needs to be relaxed into ADRP + ADD. | ||
.globl foo | ||
.type foo, %function | ||
foo: | ||
.cfi_startproc | ||
cmp x1, x11 | ||
b.hi .L2 | ||
mov x0, #0x0 | ||
.L2: | ||
# CHECK-FOO: <foo.cold.0>: | ||
adr x1, foo | ||
# CHECK-FOO: adrp | ||
# CHECK-FOO-NEXT: add | ||
ret x30 | ||
.cfi_endproc | ||
.size foo, .-foo | ||
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## Force relocation mode. | ||
.reloc 0, R_AARCH64_NONE |