Debug Info: Implement DwarfUnit::addRegisterOffset using DwarfExpression.

No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225707 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp

@@ -42,6 +42,9 @@ public:
   void EmitOp(uint8_t Op, const char* Comment) override;
   void EmitSigned(int Value) override;
   void EmitUnsigned(unsigned Value) override;
+  unsigned getFrameRegister() override {
+    llvm_unreachable("not available");
+  };
 };
 
 void DebugLocDwarfExpression::EmitOp(uint8_t Op, const char* Comment) {

lib/CodeGen/AsmPrinter/DwarfExpression.cpp

@@ -65,6 +65,22 @@ void DwarfExpression::AddShr(unsigned ShiftBy) {
   EmitOp(dwarf::DW_OP_shr);
 }
 
+bool DwarfExpression::AddMachineRegIndirect(unsigned MachineReg, int Offset) {
+  const TargetRegisterInfo *TRI = TM.getSubtargetImpl()->getRegisterInfo();
+  int DwarfReg = TRI->getDwarfRegNum(MachineReg, false);
+  if (DwarfReg < 0)
+    return false;
+
+  if (MachineReg == getFrameRegister()) {
+    // If variable offset is based in frame register then use fbreg.
+    EmitOp(dwarf::DW_OP_fbreg);
+    EmitSigned(Offset);
+  } else {
+    AddRegIndirect(DwarfReg, Offset);
+  }
+  return true;
+}
+
 void DwarfExpression::AddMachineRegPiece(unsigned MachineReg,
                                          unsigned PieceSizeInBits,
                                          unsigned PieceOffsetInBits) {

lib/CodeGen/AsmPrinter/DwarfExpression.h

@@ -24,6 +24,7 @@ class TargetMachine;
 /// independently of whether they are emitted into a DIE or into a .debug_loc
 /// entry.
 class DwarfExpression {
+protected:
   TargetMachine &TM;
 public:
   DwarfExpression(TargetMachine &TM) : TM(TM) {}
@@ -31,6 +32,9 @@ public:
   virtual void EmitOp(uint8_t Op, const char* Comment = nullptr) = 0;
   virtual void EmitSigned(int Value) = 0;
   virtual void EmitUnsigned(unsigned Value) = 0;
+
+  virtual unsigned getFrameRegister() = 0;
+
   /// Emit a dwarf register operation.
   void AddReg(int DwarfReg, const char* Comment = nullptr);
   /// Emit an (double-)indirect dwarf register operation.
@@ -43,6 +47,10 @@ public:
   /// Emit a shift-right dwarf expression.
   void AddShr(unsigned ShiftBy);
 
+  /// Emit an indirect dwarf register operation for the given machine register.
+  /// Returns false if no DWARF register exists for MachineReg.
+  bool AddMachineRegIndirect(unsigned MachineReg, int Offset);
+
   /// \brief Emit a partial DWARF register operation.
   /// \param MLoc             the register
   /// \param PieceSize        size and

lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -16,6 +16,7 @@
 #include "DwarfAccelTable.h"
 #include "DwarfCompileUnit.h"
 #include "DwarfDebug.h"
+#include "DwarfExpression.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DIBuilder.h"
@@ -43,6 +44,35 @@ GenerateDwarfTypeUnits("generate-type-units", cl::Hidden,
                        cl::desc("Generate DWARF4 type units."),
                        cl::init(false));
 
+/// DwarfExpression implementation for DwarfUnit.
+class DIEDwarfExpression : public DwarfExpression {
+  DwarfUnit &DU;
+  DIELoc ¨
+public:
+  DIEDwarfExpression(TargetMachine &TM, DwarfUnit &DU, DIELoc &DIE)
+  : DwarfExpression(TM), DU(DU), DIE(DIE) {}
+
+  void EmitOp(uint8_t Op, const char* Comment = nullptr) override;
+  void EmitSigned(int Value) override;
+  void EmitUnsigned(unsigned Value) override;
+  unsigned getFrameRegister() override;
+};
+
+void DIEDwarfExpression::EmitOp(uint8_t Op, const char* Comment) {
+  DU.addUInt(DIE, dwarf::DW_FORM_data1, Op);
+}
+void DIEDwarfExpression::EmitSigned(int Value) {
+  DU.addSInt(DIE, dwarf::DW_FORM_sdata, Value);
+}
+void DIEDwarfExpression::EmitUnsigned(unsigned Value) {
+  DU.addUInt(DIE, dwarf::DW_FORM_udata, Value);
+}
+unsigned DIEDwarfExpression::getFrameRegister() {
+  const TargetRegisterInfo *TRI = TM.getSubtargetImpl()->getRegisterInfo();
+  return TRI->getFrameRegister(*DU.getAsmPrinter()->MF);
+}
+
+
 /// Unit - Unit constructor.
 DwarfUnit::DwarfUnit(unsigned UID, dwarf::Tag UnitTag, DICompileUnit Node,
                      AsmPrinter *A, DwarfDebug *DW, DwarfFile *DWU)
@@ -463,22 +493,8 @@ bool DwarfUnit::addRegisterOpPiece(DIELoc &TheDie, unsigned Reg,
 /// addRegisterOffset - Add register offset.
 bool DwarfUnit::addRegisterOffset(DIELoc &TheDie, unsigned Reg,
                                   int64_t Offset) {
-  const TargetRegisterInfo *TRI = Asm->TM.getSubtargetImpl()->getRegisterInfo();
-  int DWReg = TRI->getDwarfRegNum(Reg, false);
-  if (DWReg < 0)
-    return false;
-
-  if (Reg == TRI->getFrameRegister(*Asm->MF))
-    // If variable offset is based in frame register then use fbreg.
-    addUInt(TheDie, dwarf::DW_FORM_data1, dwarf::DW_OP_fbreg);
-  else if (DWReg < 32)
-    addUInt(TheDie, dwarf::DW_FORM_data1, dwarf::DW_OP_breg0 + DWReg);
-  else {
-    addUInt(TheDie, dwarf::DW_FORM_data1, dwarf::DW_OP_bregx);
-    addUInt(TheDie, dwarf::DW_FORM_udata, DWReg);
-  }
-  addSInt(TheDie, dwarf::DW_FORM_sdata, Offset);
-  return true;
+  DIEDwarfExpression Expr(Asm->TM, *this, TheDie);
+  return Expr.AddMachineRegIndirect(Reg, Offset);
 }
 
 /* Byref variables, in Blocks, are declared by the programmer as "SomeType

lib/CodeGen/AsmPrinter/DwarfUnit.h

@@ -138,6 +138,7 @@ public:
   }
 
   // Accessors.
+  AsmPrinter* getAsmPrinter() const { return Asm; }
   unsigned getUniqueID() const { return UniqueID; }
   uint16_t getLanguage() const { return CUNode.getLanguage(); }
   DICompileUnit getCUNode() const { return CUNode; }