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[AArch64][MachineOutliner] Don't outline CFI instructions 

CFI instructions can only safely be outlined when the outlined call is a tail
call, or when the outlined frame is fixed up.

For the sake of correctness, disable outlining from CFI instructions.

Add machine-outliner-cfi.mir to test this.
This commit is contained in:
Jessica Paquette 2020-03-02 10:49:18 -08:00
parent e20e6f26fa
commit 02c154a9cb
2 changed files with 71 additions and 0 deletions
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8
llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
View File

@ -6158,6 +6158,14 @@ AArch64InstrInfo::getOutliningType(MachineBasicBlock::iterator &MIT,
if (FuncInfo->getLOHRelated().count(&MI))
return outliner::InstrType::Illegal;
// We can only outline these if we will tail call the outlined function, or
// fix up the CFI offsets. For the sake of safety, don't outline CFI
// instructions.
//
// FIXME: If the proper fixups are implemented, this should be possible.
if (MI.isCFIInstruction())
return outliner::InstrType::Illegal;
// Don't allow debug values to impact outlining type.
if (MI.isDebugInstr() || MI.isIndirectDebugValue())
return outliner::InstrType::Invisible;

63
llvm/test/CodeGen/AArch64/machine-outliner-cfi.mir Normal file
View File

@ -0,0 +1,63 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -mtriple=aarch64-apple-unknown -run-pass=machine-outliner -verify-machineinstrs %s -o - | FileCheck %s
# Outlining CFI instructions is unsafe. It is possible if the call is tail
# called, but otherwise, it requires fixups. Show that we don't include CFI
# instructions in outlined sequences right now.
--- |
define void @foo() #0 { ret void }
define void @bar() #0 { ret void }
define void @baz() #0 { ret void }
attributes #0 = { noredzone }
...
---
name: foo
tracksRegLiveness: true
body: |
bb.0:
liveins: $lr
; CHECK-LABEL: name: foo
; CHECK: liveins: $lr
; CHECK: frame-setup CFI_INSTRUCTION def_cfa $w29, 16
; CHECK: TCRETURNdi @OUTLINED_FUNCTION_0, 0, implicit $sp, implicit-def $w12, implicit-def $w13, implicit-def $w14, implicit-def $w15
frame-setup CFI_INSTRUCTION def_cfa $w29, 16
$w12 = ORRWri $wzr, 1
$w13 = ORRWri $wzr, 2
$w14 = ORRWri $wzr, 3
$w15 = ORRWri $wzr, 4
RET undef $lr
...
---
name: bar
tracksRegLiveness: true
body: |
bb.0:
liveins: $lr
; CHECK-LABEL: name: bar
; CHECK: liveins: $lr
; CHECK: frame-setup CFI_INSTRUCTION def_cfa $w29, 16
; CHECK: TCRETURNdi @OUTLINED_FUNCTION_0, 0, implicit $sp, implicit-def $w12, implicit-def $w13, implicit-def $w14, implicit-def $w15
frame-setup CFI_INSTRUCTION def_cfa $w29, 16
$w12 = ORRWri $wzr, 1
$w13 = ORRWri $wzr, 2
$w14 = ORRWri $wzr, 3
$w15 = ORRWri $wzr, 4
RET undef $lr
...
---
name: baz
tracksRegLiveness: true
body: |
bb.0:
liveins: $lr
; CHECK-LABEL: name: baz
; CHECK: liveins: $lr
; CHECK: frame-setup CFI_INSTRUCTION def_cfa $w29, 16
; CHECK: TCRETURNdi @OUTLINED_FUNCTION_0, 0, implicit $sp, implicit-def $w12, implicit-def $w13, implicit-def $w14, implicit-def $w15
frame-setup CFI_INSTRUCTION def_cfa $w29, 16
$w12 = ORRWri $wzr, 1
$w13 = ORRWri $wzr, 2
$w14 = ORRWri $wzr, 3
$w15 = ORRWri $wzr, 4
RET undef $lr