Commit 02c154a9 authored by Jessica Paquette's avatar Jessica Paquette
Browse files

[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.
parent e20e6f26

llvm/lib/Target/AArch64/AArch64InstrInfo.cpp

+8 −0
Original line number Diff line number Diff line
@@ -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;

llvm/test/CodeGen/AArch64/machine-outliner-cfi.mir

0 → 100644
+63 −0
Original line number Diff line number Diff line 
# 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