Make DwarfExpression use the new DIExpressionIterator. NFC.

[opencl/llvm.git] / lib / CodeGen / AsmPrinter / DwarfExpression.cpp

diff --git a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
index 1df0ea4f79f2fe9bedc1070ed90cf41c6216f007..d1b648ffabca5bccd04a311ed63295c279bc7af3 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
@@ -12,7 +12,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "DwarfExpression.h"
-
 #include "DwarfDebug.h"
 #include "llvm/ADT/SmallBitVector.h"
 #include "llvm/CodeGen/AsmPrinter.h"
@@ -79,7 +78,7 @@ bool DwarfExpression::AddMachineRegIndirect(unsigned MachineReg, int Offset) {
   if (DwarfReg < 0)
     return false;
 
-  if (MachineReg == getFrameRegister()) {
+  if (isFrameRegister(MachineReg)) {
     // If variable offset is based in frame register then use fbreg.
     EmitOp(dwarf::DW_OP_fbreg);
     EmitSigned(Offset);
@@ -89,7 +88,7 @@ bool DwarfExpression::AddMachineRegIndirect(unsigned MachineReg, int Offset) {
   return true;
 }
 
-void DwarfExpression::AddMachineRegPiece(unsigned MachineReg,
+bool DwarfExpression::AddMachineRegPiece(unsigned MachineReg,
                                          unsigned PieceSizeInBits,
                                          unsigned PieceOffsetInBits) {
   const TargetRegisterInfo *TRI = getTRI();
@@ -100,7 +99,7 @@ void DwarfExpression::AddMachineRegPiece(unsigned MachineReg,
     AddReg(Reg);
     if (PieceSizeInBits)
       AddOpPiece(PieceSizeInBits, PieceOffsetInBits);
-    return;
+    return true;
   }
 
   // Walk up the super-register chain until we find a valid number.
@@ -123,7 +122,7 @@ void DwarfExpression::AddMachineRegPiece(unsigned MachineReg,
           AddShr(RegOffset);
         AddOpPiece(Size, PieceOffsetInBits);
       }
-      return;
+      return true;
     }
   }
 
@@ -162,9 +161,7 @@ void DwarfExpression::AddMachineRegPiece(unsigned MachineReg,
     }
   }
 
-  if (CurPos == PieceOffsetInBits)
-    // FIXME: We have no reasonable way of handling errors in here.
-    EmitOp(dwarf::DW_OP_nop, "nop (could not find a dwarf register number)");
+  return CurPos > PieceOffsetInBits;
 }
 
 void DwarfExpression::AddSignedConstant(int Value) {
@@ -191,3 +188,80 @@ void DwarfExpression::AddUnsignedConstant(unsigned Value) {
   if (getDwarfVersion() >= 4)
     EmitOp(dwarf::DW_OP_stack_value);
 }
+
+static unsigned getOffsetOrZero(unsigned OffsetInBits,
+                                unsigned PieceOffsetInBits) {
+  if (OffsetInBits == PieceOffsetInBits)
+    return 0;
+  assert(OffsetInBits >= PieceOffsetInBits && "overlapping pieces");
+  return OffsetInBits;
+}
+
+bool DwarfExpression::AddMachineRegExpression(DIExpression Expr,
+                                              unsigned MachineReg,
+                                              unsigned PieceOffsetInBits) {
+  auto I = Expr.begin();
+  // Pattern-match combinations for which more efficient representations exist
+  // first.
+  if (I == Expr.end())
+    return AddMachineRegPiece(MachineReg);
+
+  bool ValidReg = false;
+  switch (*I) {
+  case dwarf::DW_OP_piece: {
+    unsigned SizeOfByte = 8;
+    unsigned OffsetInBits = I.getArg(1) * SizeOfByte;
+    unsigned SizeInBits   = I.getArg(2) * SizeOfByte;
+    // Piece always comes at the end of the expression.
+    return AddMachineRegPiece(MachineReg, SizeInBits,
+               getOffsetOrZero(OffsetInBits, PieceOffsetInBits));
+  }
+  case dwarf::DW_OP_plus:
+    // [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].
+    if (*std::next(I) == dwarf::DW_OP_deref) {
+      unsigned Offset = I.getArg(1);
+      ValidReg = AddMachineRegIndirect(MachineReg, Offset);
+      std::advance(I, 2);
+      break;
+    } else
+      ValidReg = AddMachineRegPiece(MachineReg);
+  case dwarf::DW_OP_deref:
+    // [DW_OP_reg,DW_OP_deref] --> [DW_OP_breg].
+    ValidReg = AddMachineRegIndirect(MachineReg);
+    ++I;
+    break;
+  default:
+    llvm_unreachable("unsupported operand");
+  }
+
+  if (!ValidReg)
+    return false;
+
+  // Emit remaining elements of the expression.
+  AddExpression(I, PieceOffsetInBits);
+  return true;
+}
+
+void DwarfExpression::AddExpression(DIExpressionIterator I,
+                                    unsigned PieceOffsetInBits) {
+  for (; I != DIExpressionIterator(); ++I) {
+    switch (*I) {
+    case dwarf::DW_OP_piece: {
+      unsigned SizeOfByte = 8;
+      unsigned OffsetInBits = I.getArg(1) * SizeOfByte;
+      unsigned SizeInBits   = I.getArg(2) * SizeOfByte;
+      AddOpPiece(SizeInBits, getOffsetOrZero(OffsetInBits, PieceOffsetInBits));
+      break;
+    }
+    case dwarf::DW_OP_plus:
+      EmitOp(dwarf::DW_OP_plus_uconst);
+      EmitUnsigned(I.getArg(1));
+      break;
+    case dwarf::DW_OP_deref:
+      EmitOp(dwarf::DW_OP_deref);
+      break;
+    default:
+      llvm_unreachable("unhandled opcode found in DIExpression");
+    }
+  }
+}