lib/Target/AVR/AVRAsmPrinter.cpp

   1 //===-- AVRAsmPrinter.cpp - AVR LLVM assembly writer ----------------------===//
   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 a printer that converts from our internal representation
  11 // of machine-dependent LLVM code to GAS-format AVR assembly language.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "AVR.h"
  16 #include "AVRMCInstLower.h"
  17 #include "AVRSubtarget.h"
  18 #include "InstPrinter/AVRInstPrinter.h"
  19
  20 #include "llvm/CodeGen/AsmPrinter.h"
  21 #include "llvm/CodeGen/MachineFunction.h"
  22 #include "llvm/CodeGen/MachineInstr.h"
  23 #include "llvm/CodeGen/TargetRegisterInfo.h"
  24 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  25 #include "llvm/IR/Mangler.h"
  26 #include "llvm/MC/MCInst.h"
  27 #include "llvm/MC/MCStreamer.h"
  28 #include "llvm/MC/MCSymbol.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/TargetRegistry.h"
  31 #include "llvm/Support/raw_ostream.h"
  32
  33 #define DEBUG_TYPE "avr-asm-printer"
  34
  35 namespace llvm {
  36
  37 /// An AVR assembly code printer.
  38 class AVRAsmPrinter : public AsmPrinter {
  39 public:
  40   AVRAsmPrinter(TargetMachine &TM,
  41                 std::unique_ptr<MCStreamer> Streamer)
  42       : AsmPrinter(TM, std::move(Streamer)), MRI(*TM.getMCRegisterInfo()) { }
  43
  44   StringRef getPassName() const override { return "AVR Assembly Printer"; }
  45
  46   void printOperand(const MachineInstr *MI, unsigned OpNo, raw_ostream &O,
  47                     const char *Modifier = 0);
  48
  49   bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
  50                        unsigned AsmVariant, const char *ExtraCode,
  51                        raw_ostream &O) override;
  52
  53   bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
  54                              unsigned AsmVariant, const char *ExtraCode,
  55                              raw_ostream &O) override;
  56
  57   void EmitInstruction(const MachineInstr *MI) override;
  58
  59 private:
  60   const MCRegisterInfo &MRI;
  61 };
  62
  63 void AVRAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
  64                                  raw_ostream &O, const char *Modifier) {
  65   const MachineOperand &MO = MI->getOperand(OpNo);
  66
  67   switch (MO.getType()) {
  68   case MachineOperand::MO_Register:
  69     O << AVRInstPrinter::getPrettyRegisterName(MO.getReg(), MRI);
  70     break;
  71   case MachineOperand::MO_Immediate:
  72     O << MO.getImm();
  73     break;
  74   case MachineOperand::MO_GlobalAddress:
  75     O << getSymbol(MO.getGlobal());
  76     break;
  77   case MachineOperand::MO_ExternalSymbol:
  78     O << *GetExternalSymbolSymbol(MO.getSymbolName());
  79     break;
  80   case MachineOperand::MO_MachineBasicBlock:
  81     O << *MO.getMBB()->getSymbol();
  82     break;
  83   default:
  84     llvm_unreachable("Not implemented yet!");
  85   }
  86 }
  87
  88 bool AVRAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
  89                                     unsigned AsmVariant, const char *ExtraCode,
  90                                     raw_ostream &O) {
  91   // Default asm printer can only deal with some extra codes,
  92   // so try it first.
  93   bool Error = AsmPrinter::PrintAsmOperand(MI, OpNum, AsmVariant, ExtraCode, O);
  94
  95   if (Error && ExtraCode && ExtraCode[0]) {
  96     if (ExtraCode[1] != 0)
  97       return true; // Unknown modifier.
  98
  99     if (ExtraCode[0] >= 'A' && ExtraCode[0] <= 'Z') {
 100       const MachineOperand &RegOp = MI->getOperand(OpNum);
 101
 102       assert(RegOp.isReg() && "Operand must be a register when you're"
 103                               "using 'A'..'Z' operand extracodes.");
 104       unsigned Reg = RegOp.getReg();
 105
 106       unsigned ByteNumber = ExtraCode[0] - 'A';
 107
 108       unsigned OpFlags = MI->getOperand(OpNum - 1).getImm();
 109       unsigned NumOpRegs = InlineAsm::getNumOperandRegisters(OpFlags);
 110       (void)NumOpRegs;
 111
 112       const AVRSubtarget &STI = MF->getSubtarget<AVRSubtarget>();
 113       const TargetRegisterInfo &TRI = *STI.getRegisterInfo();
 114
 115       const TargetRegisterClass *RC = TRI.getMinimalPhysRegClass(Reg);
 116       unsigned BytesPerReg = TRI.getRegSizeInBits(*RC) / 8;
 117       assert(BytesPerReg <= 2 && "Only 8 and 16 bit regs are supported.");
 118
 119       unsigned RegIdx = ByteNumber / BytesPerReg;
 120       assert(RegIdx < NumOpRegs && "Multibyte index out of range.");
 121
 122       Reg = MI->getOperand(OpNum + RegIdx).getReg();
 123
 124       if (BytesPerReg == 2) {
 125         Reg = TRI.getSubReg(Reg, ByteNumber % BytesPerReg ? AVR::sub_hi
 126                                                           : AVR::sub_lo);
 127       }
 128
 129       O << AVRInstPrinter::getPrettyRegisterName(Reg, MRI);
 130       return false;
 131     }
 132   }
 133
 134   if (Error)
 135     printOperand(MI, OpNum, O);
 136
 137   return false;
 138 }
 139
 140 bool AVRAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
 141                                           unsigned OpNum, unsigned AsmVariant,
 142                                           const char *ExtraCode,
 143                                           raw_ostream &O) {
 144   if (ExtraCode && ExtraCode[0]) {
 145     llvm_unreachable("This branch is not implemented yet");
 146   }
 147
 148   const MachineOperand &MO = MI->getOperand(OpNum);
 149   (void)MO;
 150   assert(MO.isReg() && "Unexpected inline asm memory operand");
 151
 152   // TODO: We should be able to look up the alternative name for
 153   // the register if it's given.
 154   // TableGen doesn't expose a way of getting retrieving names
 155   // for registers.
 156   if (MI->getOperand(OpNum).getReg() == AVR::R31R30) {
 157     O << "Z";
 158   } else {
 159     assert(MI->getOperand(OpNum).getReg() == AVR::R29R28 &&
 160            "Wrong register class for memory operand.");
 161     O << "Y";
 162   }
 163
 164   // If NumOpRegs == 2, then we assume it is product of a FrameIndex expansion
 165   // and the second operand is an Imm.
 166   unsigned OpFlags = MI->getOperand(OpNum - 1).getImm();
 167   unsigned NumOpRegs = InlineAsm::getNumOperandRegisters(OpFlags);
 168
 169   if (NumOpRegs == 2) {
 170     O << '+' << MI->getOperand(OpNum + 1).getImm();
 171   }
 172
 173   return false;
 174 }
 175
 176 void AVRAsmPrinter::EmitInstruction(const MachineInstr *MI) {
 177   AVRMCInstLower MCInstLowering(OutContext, *this);
 178
 179   MCInst I;
 180   MCInstLowering.lowerInstruction(*MI, I);
 181   EmitToStreamer(*OutStreamer, I);
 182 }
 183
 184 } // end of namespace llvm
 185
 186 extern "C" void LLVMInitializeAVRAsmPrinter() {
 187   llvm::RegisterAsmPrinter<llvm::AVRAsmPrinter> X(llvm::getTheAVRTarget());
 188 }
 189