1 //===-- llvm/CodeGen/DwarfExpression.h - Dwarf Compile Unit ---*- C++ -*--===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file contains support for writing dwarf compile unit. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFEXPRESSION_H 15 #define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFEXPRESSION_H 16 17 #include "llvm/IR/DebugInfo.h" 18 #include "llvm/Support/DataTypes.h" 19 20 namespace llvm { 21 22 class AsmPrinter; 23 class ByteStreamer; 24 class TargetRegisterInfo; 25 class DwarfUnit; 26 class DIELoc; 27 28 /// Base class containing the logic for constructing DWARF expressions 29 /// independently of whether they are emitted into a DIE or into a .debug_loc 30 /// entry. 31 class DwarfExpression { 32 protected: 33 // Various convenience accessors that extract things out of AsmPrinter. 34 const TargetRegisterInfo &TRI; 35 unsigned DwarfVersion; 36 37 public: DwarfExpression(const TargetRegisterInfo & TRI,unsigned DwarfVersion)38 DwarfExpression(const TargetRegisterInfo &TRI, 39 unsigned DwarfVersion) 40 : TRI(TRI), DwarfVersion(DwarfVersion) {} ~DwarfExpression()41 virtual ~DwarfExpression() {} 42 43 /// Output a dwarf operand and an optional assembler comment. 44 virtual void EmitOp(uint8_t Op, const char *Comment = nullptr) = 0; 45 /// Emit a raw signed value. 46 virtual void EmitSigned(int64_t Value) = 0; 47 /// Emit a raw unsigned value. 48 virtual void EmitUnsigned(uint64_t Value) = 0; 49 /// Return whether the given machine register is the frame register in the 50 /// current function. 51 virtual bool isFrameRegister(unsigned MachineReg) = 0; 52 53 /// Emit a dwarf register operation. 54 void AddReg(int DwarfReg, const char *Comment = nullptr); 55 /// Emit an (double-)indirect dwarf register operation. 56 void AddRegIndirect(int DwarfReg, int Offset, bool Deref = false); 57 58 /// Emit a dwarf register operation for describing 59 /// - a small value occupying only part of a register or 60 /// - a register representing only part of a value. 61 void AddOpPiece(unsigned SizeInBits, unsigned OffsetInBits = 0); 62 /// Emit a shift-right dwarf expression. 63 void AddShr(unsigned ShiftBy); 64 65 /// Emit an indirect dwarf register operation for the given machine register. 66 /// \return false if no DWARF register exists for MachineReg. 67 bool AddMachineRegIndirect(unsigned MachineReg, int Offset = 0); 68 69 /// \brief Emit a partial DWARF register operation. 70 /// \param MachineReg the register 71 /// \param PieceSizeInBits size and 72 /// \param PieceOffsetInBits offset of the piece in bits, if this is one 73 /// piece of an aggregate value. 74 /// 75 /// If size and offset is zero an operation for the entire 76 /// register is emitted: Some targets do not provide a DWARF 77 /// register number for every register. If this is the case, this 78 /// function will attempt to emit a DWARF register by emitting a 79 /// piece of a super-register or by piecing together multiple 80 /// subregisters that alias the register. 81 /// 82 /// \return false if no DWARF register exists for MachineReg. 83 bool AddMachineRegPiece(unsigned MachineReg, unsigned PieceSizeInBits = 0, 84 unsigned PieceOffsetInBits = 0); 85 86 /// Emit a signed constant. 87 void AddSignedConstant(int Value); 88 /// Emit an unsigned constant. 89 void AddUnsignedConstant(unsigned Value); 90 91 /// \brief Emit an entire expression on top of a machine register location. 92 /// 93 /// \param PieceOffsetInBits If this is one piece out of a fragmented 94 /// location, this is the offset of the piece inside the entire variable. 95 /// \return false if no DWARF register exists for MachineReg. 96 bool AddMachineRegExpression(const DIExpression *Expr, unsigned MachineReg, 97 unsigned PieceOffsetInBits = 0); 98 /// Emit a the operations remaining the DIExpressionIterator I. 99 /// \param PieceOffsetInBits If this is one piece out of a fragmented 100 /// location, this is the offset of the piece inside the entire variable. 101 void AddExpression(DIExpression::expr_op_iterator I, 102 DIExpression::expr_op_iterator E, 103 unsigned PieceOffsetInBits = 0); 104 }; 105 106 /// DwarfExpression implementation for .debug_loc entries. 107 class DebugLocDwarfExpression : public DwarfExpression { 108 ByteStreamer &BS; 109 110 public: DebugLocDwarfExpression(const TargetRegisterInfo & TRI,unsigned DwarfVersion,ByteStreamer & BS)111 DebugLocDwarfExpression(const TargetRegisterInfo &TRI, 112 unsigned DwarfVersion, ByteStreamer &BS) 113 : DwarfExpression(TRI, DwarfVersion), BS(BS) {} 114 115 void EmitOp(uint8_t Op, const char *Comment = nullptr) override; 116 void EmitSigned(int64_t Value) override; 117 void EmitUnsigned(uint64_t Value) override; 118 bool isFrameRegister(unsigned MachineReg) override; 119 }; 120 121 /// DwarfExpression implementation for singular DW_AT_location. 122 class DIEDwarfExpression : public DwarfExpression { 123 const AsmPrinter ≈ 124 DwarfUnit &DU; 125 DIELoc ¨ 126 127 public: 128 DIEDwarfExpression(const AsmPrinter &AP, DwarfUnit &DU, DIELoc &DIE); 129 void EmitOp(uint8_t Op, const char *Comment = nullptr) override; 130 void EmitSigned(int64_t Value) override; 131 void EmitUnsigned(uint64_t Value) override; 132 bool isFrameRegister(unsigned MachineReg) override; 133 }; 134 } 135 136 #endif 137