[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

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index 0164905a3e0..585524ebbf2 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -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)