686ec6cfe8
On some AArch64 machines the splitting was inconsistent.
This causes cold `foo` to have a `mov` instruction before adrp.
```
<foo.cold.0>:
mov x0, #0x0 // =0
adrp x1, 0x600000 <_start>
add x1, x1, #0x14
ret
```
This patch removes the `mov` instruction right above .L2, making
splitting deterministic.
63 lines
1.4 KiB
ArmAsm
63 lines
1.4 KiB
ArmAsm
## 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
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# RUN: %clang %cflags %t.o -o %t.exe -Wl,-q -static
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# RUN: llvm-bolt %t.exe -o %t.bolt --split-functions --split-strategy=random2
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# RUN: llvm-objdump -d -j .text %t.bolt | FileCheck %s
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# RUN: llvm-objdump -d --disassemble-symbols=foo.cold.0 %t.bolt \
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# RUN: | FileCheck --check-prefix=CHECK-FOO %s
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## ADR below references its containing function that is split. But ADR is always
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## in the main fragment, thus there is no need to relax it.
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.text
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.globl _start
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.type _start, %function
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_start:
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.cfi_startproc
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# CHECK: <_start>:
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# CHECK-NEXT: adr
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adr x1, _start
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cmp x1, x11
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b.hi .L1
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mov x0, #0x0
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.L1:
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ret x30
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.cfi_endproc
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.size _start, .-_start
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## In foo, ADR is in the split fragment but references the main one. Thus, it
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## needs to be relaxed into ADRP + ADD.
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.globl foo
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.type foo, %function
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foo:
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.cfi_startproc
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cmp x1, x11
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b.hi .L2
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.L2:
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# CHECK-FOO: <foo.cold.0>:
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# CHECK-FOO-NEXT: adrp
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# CHECK-FOO-NEXT: add
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adr x1, foo
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ret x30
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.cfi_endproc
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.size foo, .-foo
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## bar is a non-simple function. We can still relax ADR, because it has a
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## preceding NOP.
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.globl bar
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.type bar, %function
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bar:
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.cfi_startproc
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# CHECK-LABEL: <bar>:
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# CHECK-NEXT: adrp
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# CHECK-NEXT: add
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nop
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adr x0, foo
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adr x1, .L3
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br x1
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.L3:
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ret x0
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.cfi_endproc
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.size bar, .-bar
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