[ARM] Use helper class for emitting CFI instructions into MIR (#135994)

Similar to #135845.

PR: llvm/llvm-project#135994

Author: s-barannikov

llvm/include/llvm/CodeGen/CFIInstBuilder.h

@@ -45,6 +45,10 @@ class CFIInstBuilder {
     setInsertPoint(InsertPt);
   }
 
+  CFIInstBuilder(MachineBasicBlock *MBB, MachineInstr::MIFlag MIFlag,
+                 bool IsEH = true)
+      : CFIInstBuilder(*MBB, MBB->end(), MIFlag, IsEH) {}
+
   void setInsertPoint(MachineBasicBlock::iterator IP) { InsertPt = IP; }
 
   void insertCFIInst(const MCCFIInstruction &CFIInst) const {
@@ -72,11 +76,27 @@ class CFIInstBuilder {
         nullptr, TRI.getDwarfRegNum(Reg, IsEH), Offset));
   }
 
+  void buildRegister(MCRegister Reg1, MCRegister Reg2) const {
+    insertCFIInst(MCCFIInstruction::createRegister(
+        nullptr, TRI.getDwarfRegNum(Reg1, IsEH),
+        TRI.getDwarfRegNum(Reg2, IsEH)));
+  }
+
   void buildRestore(MCRegister Reg) const {
     insertCFIInst(MCCFIInstruction::createRestore(
         nullptr, TRI.getDwarfRegNum(Reg, IsEH)));
   }
 
+  void buildUndefined(MCRegister Reg) const {
+    insertCFIInst(MCCFIInstruction::createUndefined(
+        nullptr, TRI.getDwarfRegNum(Reg, IsEH)));
+  }
+
+  void buildSameValue(MCRegister Reg) const {
+    insertCFIInst(MCCFIInstruction::createSameValue(
+        nullptr, TRI.getDwarfRegNum(Reg, IsEH)));
+  }
+
   void buildEscape(StringRef Bytes, StringRef Comment = "") const {
     insertCFIInst(
         MCCFIInstruction::createEscape(nullptr, Bytes, SMLoc(), Comment));

llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp

@@ -24,6 +24,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/CodeGen/CFIInstBuilder.h"
 #include "llvm/CodeGen/DFAPacketizer.h"
 #include "llvm/CodeGen/LiveVariables.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
@@ -6485,51 +6486,20 @@ void ARMBaseInstrInfo::saveLROnStack(MachineBasicBlock &MBB,
   if (!CFI)
     return;
 
-  MachineFunction &MF = *MBB.getParent();
-
   // Add a CFI, saying CFA is offset by Align bytes from SP.
-  int64_t StackPosEntry =
-      MF.addFrameInst(MCCFIInstruction::cfiDefCfaOffset(nullptr, Align));
-  BuildMI(MBB, It, DebugLoc(), get(ARM::CFI_INSTRUCTION))
-      .addCFIIndex(StackPosEntry)
-      .setMIFlags(MachineInstr::FrameSetup);
+  CFIInstBuilder CFIBuilder(MBB, It, MachineInstr::FrameSetup);
+  CFIBuilder.buildDefCFAOffset(Align);
 
   // Add a CFI saying that the LR that we want to find is now higher than
   // before.
   int LROffset = Auth ? Align - 4 : Align;
-  const MCRegisterInfo *MRI = Subtarget.getRegisterInfo();
-  unsigned DwarfLR = MRI->getDwarfRegNum(ARM::LR, true);
-  int64_t LRPosEntry = MF.addFrameInst(
-      MCCFIInstruction::createOffset(nullptr, DwarfLR, -LROffset));
-  BuildMI(MBB, It, DebugLoc(), get(ARM::CFI_INSTRUCTION))
-      .addCFIIndex(LRPosEntry)
-      .setMIFlags(MachineInstr::FrameSetup);
+  CFIBuilder.buildOffset(ARM::LR, -LROffset);
   if (Auth) {
     // Add a CFI for the location of the return adddress PAC.
-    unsigned DwarfRAC = MRI->getDwarfRegNum(ARM::RA_AUTH_CODE, true);
-    int64_t RACPosEntry = MF.addFrameInst(
-        MCCFIInstruction::createOffset(nullptr, DwarfRAC, -Align));
-    BuildMI(MBB, It, DebugLoc(), get(ARM::CFI_INSTRUCTION))
-        .addCFIIndex(RACPosEntry)
-        .setMIFlags(MachineInstr::FrameSetup);
+    CFIBuilder.buildOffset(ARM::RA_AUTH_CODE, -Align);
   }
 }
 
-void ARMBaseInstrInfo::emitCFIForLRSaveToReg(MachineBasicBlock &MBB,
-                                             MachineBasicBlock::iterator It,
-                                             Register Reg) const {
-  MachineFunction &MF = *MBB.getParent();
-  const MCRegisterInfo *MRI = Subtarget.getRegisterInfo();
-  unsigned DwarfLR = MRI->getDwarfRegNum(ARM::LR, true);
-  unsigned DwarfReg = MRI->getDwarfRegNum(Reg, true);
-
-  int64_t LRPosEntry = MF.addFrameInst(
-      MCCFIInstruction::createRegister(nullptr, DwarfLR, DwarfReg));
-  BuildMI(MBB, It, DebugLoc(), get(ARM::CFI_INSTRUCTION))
-      .addCFIIndex(LRPosEntry)
-      .setMIFlags(MachineInstr::FrameSetup);
-}
-
 void ARMBaseInstrInfo::restoreLRFromStack(MachineBasicBlock &MBB,
                                           MachineBasicBlock::iterator It,
                                           bool CFI, bool Auth) const {
@@ -6560,50 +6530,18 @@ void ARMBaseInstrInfo::restoreLRFromStack(MachineBasicBlock &MBB,
   }
 
   if (CFI) {
-    // Now stack has moved back up...
-    MachineFunction &MF = *MBB.getParent();
-    const MCRegisterInfo *MRI = Subtarget.getRegisterInfo();
-    unsigned DwarfLR = MRI->getDwarfRegNum(ARM::LR, true);
-    int64_t StackPosEntry =
-        MF.addFrameInst(MCCFIInstruction::cfiDefCfaOffset(nullptr, 0));
-    BuildMI(MBB, It, DebugLoc(), get(ARM::CFI_INSTRUCTION))
-        .addCFIIndex(StackPosEntry)
-        .setMIFlags(MachineInstr::FrameDestroy);
-
-    // ... and we have restored LR.
-    int64_t LRPosEntry =
-        MF.addFrameInst(MCCFIInstruction::createRestore(nullptr, DwarfLR));
-    BuildMI(MBB, It, DebugLoc(), get(ARM::CFI_INSTRUCTION))
-        .addCFIIndex(LRPosEntry)
-        .setMIFlags(MachineInstr::FrameDestroy);
-
-    if (Auth) {
-      unsigned DwarfRAC = MRI->getDwarfRegNum(ARM::RA_AUTH_CODE, true);
-      int64_t Entry =
-          MF.addFrameInst(MCCFIInstruction::createUndefined(nullptr, DwarfRAC));
-      BuildMI(MBB, It, DebugLoc(), get(ARM::CFI_INSTRUCTION))
-          .addCFIIndex(Entry)
-          .setMIFlags(MachineInstr::FrameDestroy);
-    }
+    // Now stack has moved back up and we have restored LR.
+    CFIInstBuilder CFIBuilder(MBB, It, MachineInstr::FrameDestroy);
+    CFIBuilder.buildDefCFAOffset(0);
+    CFIBuilder.buildRestore(ARM::LR);
+    if (Auth)
+      CFIBuilder.buildUndefined(ARM::RA_AUTH_CODE);
   }
 
   if (Auth)
     BuildMI(MBB, It, DebugLoc(), get(ARM::t2AUT));
 }
 
-void ARMBaseInstrInfo::emitCFIForLRRestoreFromReg(
-    MachineBasicBlock &MBB, MachineBasicBlock::iterator It) const {
-  MachineFunction &MF = *MBB.getParent();
-  const MCRegisterInfo *MRI = Subtarget.getRegisterInfo();
-  unsigned DwarfLR = MRI->getDwarfRegNum(ARM::LR, true);
-
-  int64_t LRPosEntry =
-      MF.addFrameInst(MCCFIInstruction::createRestore(nullptr, DwarfLR));
-  BuildMI(MBB, It, DebugLoc(), get(ARM::CFI_INSTRUCTION))
-      .addCFIIndex(LRPosEntry)
-      .setMIFlags(MachineInstr::FrameDestroy);
-}
-
 void ARMBaseInstrInfo::buildOutlinedFrame(
     MachineBasicBlock &MBB, MachineFunction &MF,
     const outliner::OutlinedFunction &OF) const {
@@ -6722,11 +6660,12 @@ MachineBasicBlock::iterator ARMBaseInstrInfo::insertOutlinedCall(
     // Save and restore LR from that register.
     copyPhysReg(MBB, It, DebugLoc(), Reg, ARM::LR, true);
     if (!AFI.isLRSpilled())
-      emitCFIForLRSaveToReg(MBB, It, Reg);
+      CFIInstBuilder(MBB, It, MachineInstr::FrameSetup)
+          .buildRegister(ARM::LR, Reg);
     CallPt = MBB.insert(It, CallMIB);
     copyPhysReg(MBB, It, DebugLoc(), ARM::LR, Reg, true);
     if (!AFI.isLRSpilled())
-      emitCFIForLRRestoreFromReg(MBB, It);
+      CFIInstBuilder(MBB, It, MachineInstr::FrameDestroy).buildRestore(ARM::LR);
     It--;
     return CallPt;
   }

llvm/lib/Target/ARM/ARMBaseInstrInfo.h

@@ -409,16 +409,6 @@ class ARMBaseInstrInfo : public ARMGenInstrInfo {
                           MachineBasicBlock::iterator It, bool CFI,
                           bool Auth) const;
 
-  /// Emit CFI instructions into the MachineBasicBlock \p MBB at position \p It,
-  /// for the case when the LR is saved in the register \p Reg.
-  void emitCFIForLRSaveToReg(MachineBasicBlock &MBB,
-                             MachineBasicBlock::iterator It,
-                             Register Reg) const;
-
-  /// Emit CFI instructions into the MachineBasicBlock \p MBB at position \p It,
-  /// after the LR is was restored from a register.
-  void emitCFIForLRRestoreFromReg(MachineBasicBlock &MBB,
-                                  MachineBasicBlock::iterator It) const;
   /// \brief Sets the offsets on outlined instructions in \p MBB which use SP
   /// so that they will be valid post-outlining.
   ///