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[MachineOutliner] AArch64: Emit CFI instructions when outlining calls 

When outlining calls, the outliner needs to update CFI to ensure that, say,
exception handling works. This commit adds that functionality and adds a test
just for call outlining.

Call outlining stuff in machine-outliner.mir should be moved into
machine-outliner-calls.mir in a later commit.

llvm-svn: 327917
This commit is contained in:
Jessica Paquette 2018-03-19 22:48:40 +00:00
parent 956fec2a4a
commit 563548d8f3
2 changed files with 86 additions and 0 deletions
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19
llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
View File

@ -5282,6 +5282,25 @@ void AArch64InstrInfo::insertOutlinerEpilogue(
.addImm(-16);
It = MBB.insert(It, STRXpre);
const TargetSubtargetInfo &STI = MF.getSubtarget();
const MCRegisterInfo *MRI = STI.getRegisterInfo();
unsigned DwarfReg = MRI->getDwarfRegNum(AArch64::LR, true);
// Add a CFI saying the stack was moved 16 B down.
int64_t StackPosEntry =
MF.addFrameInst(MCCFIInstruction::createDefCfaOffset(nullptr, 16));
BuildMI(MBB, It, DebugLoc(), get(AArch64::CFI_INSTRUCTION))
.addCFIIndex(StackPosEntry)
.setMIFlags(MachineInstr::FrameSetup);
// Add a CFI saying that the LR that we want to find is now 16 B higher than
// before.
int64_t LRPosEntry =
MF.addFrameInst(MCCFIInstruction::createOffset(nullptr, DwarfReg, 16));
BuildMI(MBB, It, DebugLoc(), get(AArch64::CFI_INSTRUCTION))
.addCFIIndex(LRPosEntry)
.setMIFlags(MachineInstr::FrameSetup);
// Insert a restore before the terminator for the function.
MachineInstr *LDRXpost = BuildMI(MF, DebugLoc(), get(AArch64::LDRXpost))
.addReg(AArch64::SP, RegState::Define)

67
llvm/test/CodeGen/AArch64/machine-outliner-calls.mir Normal file
View File

@ -0,0 +1,67 @@
# RUN: llc -simplify-mir -mtriple=aarch64--- -run-pass=machine-outliner -verify-machineinstrs %s -o - | FileCheck %s
--- |
define void @baz() #0 {
ret void
}
define void @bar(i32 %a) #0 {
ret void
}
attributes #0 = { noredzone }
...
---
name: bar
tracksRegLiveness: true
body: |
bb.0:
liveins: $w0, $lr, $w8
$sp = frame-setup SUBXri $sp, 32, 0
$fp = frame-setup ADDXri $sp, 16, 0
bb.1:
BL @baz, implicit-def dead $lr, implicit $sp
$w17 = ORRWri $wzr, 1
$w17 = ORRWri $wzr, 1
$w0 = ORRWri $wzr, 4
BL @baz, implicit-def dead $lr, implicit $sp
$w17 = ORRWri $wzr, 1
$w17 = ORRWri $wzr, 1
$w0 = ORRWri $wzr, 3
BL @baz, implicit-def dead $lr, implicit $sp
$w17 = ORRWri $wzr, 1
$w17 = ORRWri $wzr, 1
$w0 = ORRWri $wzr, 2
BL @baz, implicit-def dead $lr, implicit $sp
$w17 = ORRWri $wzr, 1
$w17 = ORRWri $wzr, 1
$w0 = ORRWri $wzr, 1
bb.2:
$fp, $lr = LDPXi $sp, 2
RET undef $lr
...
---
name: baz
tracksRegLiveness: true
body: |
bb.0:
liveins: $w0, $lr, $w8
RET undef $lr
# CHECK: name: OUTLINED_FUNCTION_0
# CHECK-DAG: bb.0:
# CHECK-NEXT: liveins: $lr
# CHECK-DAG: frame-setup CFI_INSTRUCTION def_cfa_offset -16
# CHECK-NEXT: frame-setup CFI_INSTRUCTION offset $w30, 16
# CHECK-NEXT: early-clobber $sp = STRXpre $lr, $sp, -16
# CHECK-NEXT: BL @baz, implicit-def dead $lr, implicit $sp
# CHECK-NEXT: $w17 = ORRWri $wzr, 1
# CHECK-NEXT: $w17 = ORRWri $wzr, 1
# CHECK-NEXT: early-clobber $sp, $lr = LDRXpost $sp, 16
# CHECK-NEXT: RET undef $lr