Commit c0cf5f5d authored by Oliver Stannard's avatar Oliver Stannard
Browse files

[llvm-objdump] Add simple memory expressions to variable display 

Add the DW_OP_breg0..DW_OP_breg31 and DW_OP_bregx opcodes to the DWARF
expression printer.

Differential revision: https://reviews.llvm.org/D74841
parent f62b898c

llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp

+32 −1
Original line number Diff line number Diff line
@@ -387,6 +387,20 @@ static bool printCompactDWARFExpr(raw_ostream &OS, DWARFExpression::iterator I, 
      S << MRI.getName(*LLVMRegNum);

      break;

    }

    case dwarf::DW_OP_bregx: {

      int DwarfRegNum = Op.getRawOperand(0);

      int64_t Offset = Op.getRawOperand(1);

      Optional<unsigned> LLVMRegNum = MRI.getLLVMRegNum(DwarfRegNum, false);

      if (!LLVMRegNum) {

        OS << "<unknown register " << DwarfRegNum << ">";

        return false;

      }

      raw_svector_ostream S(Stack.emplace_back().String);

      S << MRI.getName(*LLVMRegNum);

      if (Offset)

        S << format("%+" PRId64, Offset);

      break;

    }

    default:

      if (Opcode >= dwarf::DW_OP_reg0 && Opcode <= dwarf::DW_OP_reg31) {

        // DW_OP_reg<N>: A register, with the register num implied by the
@@ -399,6 +413,19 @@ static bool printCompactDWARFExpr(raw_ostream &OS, DWARFExpression::iterator I, 
        }

        raw_svector_ostream S(Stack.emplace_back(PrintedExpr::Value).String);

        S << MRI.getName(*LLVMRegNum);

      } else if (Opcode >= dwarf::DW_OP_breg0 &&

                 Opcode <= dwarf::DW_OP_breg31) {

        int DwarfRegNum = Opcode - dwarf::DW_OP_breg0;

        int64_t Offset = Op.getRawOperand(0);

        Optional<unsigned> LLVMRegNum = MRI.getLLVMRegNum(DwarfRegNum, false);

        if (!LLVMRegNum) {

          OS << "<unknown register " << DwarfRegNum << ">";

          return false;

        }

        raw_svector_ostream S(Stack.emplace_back().String);

        S << MRI.getName(*LLVMRegNum);

        if (Offset)

          S << format("%+" PRId64, Offset);

      } else {

        // If we hit an unknown operand, we don't know its effect on the stack,

        // so bail out on the whole expression.
@@ -412,6 +439,10 @@ static bool printCompactDWARFExpr(raw_ostream &OS, DWARFExpression::iterator I, 
  }



  assert(Stack.size() == 1 && "expected one value on stack");



  if (Stack.front().Kind == PrintedExpr::Address)

    OS << "[" << Stack.front().String << "]";

  else

    OS << Stack.front().String;



  return true;

llvm/unittests/DebugInfo/DWARF/DWARFExpressionCompactPrinterTest.cpp

+24 −0
Original line number Diff line number Diff line
@@ -74,3 +74,27 @@ TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_reg10) { 
TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_regx) {

  TestExprPrinter({DW_OP_regx, 0x80, 0x02}, "D0");

}



TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_breg0) {

  TestExprPrinter({DW_OP_breg0, 0x04}, "[R0+4]");

}



TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_breg0_large_offset) {

  TestExprPrinter({DW_OP_breg0, 0x80, 0x02}, "[R0+256]");

}



TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_breg13) {

  TestExprPrinter({DW_OP_breg13, 0x10}, "[SP+16]");

}



TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_breg13_zero_offset) {

  TestExprPrinter({DW_OP_breg13, 0x00}, "[SP]");

}



TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_breg0_negative) {

  TestExprPrinter({DW_OP_breg0, 0x70}, "[R0-16]");

}



TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_bregx) {

  TestExprPrinter({DW_OP_bregx, 0x0d, 0x28}, "[SP+40]");

}