1 //===-- X86InstrBuilder.h - Functions to aid building x86 insts -*- 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 exposes functions that may be used with BuildMI from the 11 // MachineInstrBuilder.h file to handle X86'isms in a clean way. 12 // 13 // The BuildMem function may be used with the BuildMI function to add entire 14 // memory references in a single, typed, function call. X86 memory references 15 // can be very complex expressions (described in the README), so wrapping them 16 // up behind an easier to use interface makes sense. Descriptions of the 17 // functions are included below. 18 // 19 // For reference, the order of operands for memory references is: 20 // (Operand), Base, Scale, Index, Displacement. 21 // 22 //===----------------------------------------------------------------------===// 23 24 #ifndef X86INSTRBUILDER_H 25 #define X86INSTRBUILDER_H 26 27 #include "llvm/CodeGen/MachineFrameInfo.h" 28 #include "llvm/CodeGen/MachineInstrBuilder.h" 29 #include "llvm/CodeGen/MachineMemOperand.h" 30 31 namespace llvm { 32 33 /// X86AddressMode - This struct holds a generalized full x86 address mode. 34 /// The base register can be a frame index, which will eventually be replaced 35 /// with BP or SP and Disp being offsetted accordingly. The displacement may 36 /// also include the offset of a global value. 37 struct X86AddressMode { 38 enum { 39 RegBase, 40 FrameIndexBase 41 } BaseType; 42 43 union { 44 unsigned Reg; 45 int FrameIndex; 46 } Base; 47 48 unsigned Scale; 49 unsigned IndexReg; 50 int Disp; 51 const GlobalValue *GV; 52 unsigned GVOpFlags; 53 54 X86AddressMode() 55 : BaseType(RegBase), Scale(1), IndexReg(0), Disp(0), GV(nullptr), 56 GVOpFlags(0) { 57 Base.Reg = 0; 58 } 59 60 61 void getFullAddress(SmallVectorImpl<MachineOperand> &MO) { 62 assert(Scale == 1 || Scale == 2 || Scale == 4 || Scale == 8); 63 64 if (BaseType == X86AddressMode::RegBase) 65 MO.push_back(MachineOperand::CreateReg(Base.Reg, false, false, 66 false, false, false, 0, false)); 67 else { 68 assert(BaseType == X86AddressMode::FrameIndexBase); 69 MO.push_back(MachineOperand::CreateFI(Base.FrameIndex)); 70 } 71 72 MO.push_back(MachineOperand::CreateImm(Scale)); 73 MO.push_back(MachineOperand::CreateReg(IndexReg, false, false, 74 false, false, false, 0, false)); 75 76 if (GV) 77 MO.push_back(MachineOperand::CreateGA(GV, Disp, GVOpFlags)); 78 else 79 MO.push_back(MachineOperand::CreateImm(Disp)); 80 81 MO.push_back(MachineOperand::CreateReg(0, false, false, 82 false, false, false, 0, false)); 83 } 84 }; 85 86 /// addDirectMem - This function is used to add a direct memory reference to the 87 /// current instruction -- that is, a dereference of an address in a register, 88 /// with no scale, index or displacement. An example is: DWORD PTR [EAX]. 89 /// 90 static inline const MachineInstrBuilder & 91 addDirectMem(const MachineInstrBuilder &MIB, unsigned Reg) { 92 // Because memory references are always represented with five 93 // values, this adds: Reg, 1, NoReg, 0, NoReg to the instruction. 94 return MIB.addReg(Reg).addImm(1).addReg(0).addImm(0).addReg(0); 95 } 96 97 98 static inline const MachineInstrBuilder & 99 addOffset(const MachineInstrBuilder &MIB, int Offset) { 100 return MIB.addImm(1).addReg(0).addImm(Offset).addReg(0); 101 } 102 103 /// addRegOffset - This function is used to add a memory reference of the form 104 /// [Reg + Offset], i.e., one with no scale or index, but with a 105 /// displacement. An example is: DWORD PTR [EAX + 4]. 106 /// 107 static inline const MachineInstrBuilder & 108 addRegOffset(const MachineInstrBuilder &MIB, 109 unsigned Reg, bool isKill, int Offset) { 110 return addOffset(MIB.addReg(Reg, getKillRegState(isKill)), Offset); 111 } 112 113 /// addRegReg - This function is used to add a memory reference of the form: 114 /// [Reg + Reg]. 115 static inline const MachineInstrBuilder &addRegReg(const MachineInstrBuilder &MIB, 116 unsigned Reg1, bool isKill1, 117 unsigned Reg2, bool isKill2) { 118 return MIB.addReg(Reg1, getKillRegState(isKill1)).addImm(1) 119 .addReg(Reg2, getKillRegState(isKill2)).addImm(0).addReg(0); 120 } 121 122 static inline const MachineInstrBuilder & 123 addFullAddress(const MachineInstrBuilder &MIB, 124 const X86AddressMode &AM) { 125 assert(AM.Scale == 1 || AM.Scale == 2 || AM.Scale == 4 || AM.Scale == 8); 126 127 if (AM.BaseType == X86AddressMode::RegBase) 128 MIB.addReg(AM.Base.Reg); 129 else { 130 assert(AM.BaseType == X86AddressMode::FrameIndexBase); 131 MIB.addFrameIndex(AM.Base.FrameIndex); 132 } 133 134 MIB.addImm(AM.Scale).addReg(AM.IndexReg); 135 if (AM.GV) 136 MIB.addGlobalAddress(AM.GV, AM.Disp, AM.GVOpFlags); 137 else 138 MIB.addImm(AM.Disp); 139 140 return MIB.addReg(0); 141 } 142 143 /// addFrameReference - This function is used to add a reference to the base of 144 /// an abstract object on the stack frame of the current function. This 145 /// reference has base register as the FrameIndex offset until it is resolved. 146 /// This allows a constant offset to be specified as well... 147 /// 148 static inline const MachineInstrBuilder & 149 addFrameReference(const MachineInstrBuilder &MIB, int FI, int Offset = 0) { 150 MachineInstr *MI = MIB; 151 MachineFunction &MF = *MI->getParent()->getParent(); 152 MachineFrameInfo &MFI = *MF.getFrameInfo(); 153 const MCInstrDesc &MCID = MI->getDesc(); 154 unsigned Flags = 0; 155 if (MCID.mayLoad()) 156 Flags |= MachineMemOperand::MOLoad; 157 if (MCID.mayStore()) 158 Flags |= MachineMemOperand::MOStore; 159 MachineMemOperand *MMO = 160 MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FI, Offset), 161 Flags, MFI.getObjectSize(FI), 162 MFI.getObjectAlignment(FI)); 163 return addOffset(MIB.addFrameIndex(FI), Offset) 164 .addMemOperand(MMO); 165 } 166 167 /// addConstantPoolReference - This function is used to add a reference to the 168 /// base of a constant value spilled to the per-function constant pool. The 169 /// reference uses the abstract ConstantPoolIndex which is retained until 170 /// either machine code emission or assembly output. In PIC mode on x86-32, 171 /// the GlobalBaseReg parameter can be used to make this a 172 /// GlobalBaseReg-relative reference. 173 /// 174 static inline const MachineInstrBuilder & 175 addConstantPoolReference(const MachineInstrBuilder &MIB, unsigned CPI, 176 unsigned GlobalBaseReg, unsigned char OpFlags) { 177 //FIXME: factor this 178 return MIB.addReg(GlobalBaseReg).addImm(1).addReg(0) 179 .addConstantPoolIndex(CPI, 0, OpFlags).addReg(0); 180 } 181 182 } // End llvm namespace 183 184 #endif 185
