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      1 //===-- HexagonAsmPrinter.cpp - Print machine instrs to Hexagon assembly --===//
      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 Hexagon assembly language. This printer is
     12 // the output mechanism used by `llc'.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #include "Hexagon.h"
     17 #include "HexagonAsmPrinter.h"
     18 #include "HexagonMachineFunctionInfo.h"
     19 #include "HexagonSubtarget.h"
     20 #include "HexagonTargetMachine.h"
     21 #include "InstPrinter/HexagonInstPrinter.h"
     22 #include "MCTargetDesc/HexagonMCInst.h"
     23 #include "llvm/ADT/SmallString.h"
     24 #include "llvm/ADT/SmallVector.h"
     25 #include "llvm/ADT/StringExtras.h"
     26 #include "llvm/Analysis/ConstantFolding.h"
     27 #include "llvm/CodeGen/AsmPrinter.h"
     28 #include "llvm/CodeGen/MachineFunctionPass.h"
     29 #include "llvm/CodeGen/MachineInstr.h"
     30 #include "llvm/CodeGen/MachineInstrBuilder.h"
     31 #include "llvm/CodeGen/MachineModuleInfo.h"
     32 #include "llvm/IR/Constants.h"
     33 #include "llvm/IR/DataLayout.h"
     34 #include "llvm/IR/DerivedTypes.h"
     35 #include "llvm/IR/Mangler.h"
     36 #include "llvm/IR/Module.h"
     37 #include "llvm/MC/MCAsmInfo.h"
     38 #include "llvm/MC/MCContext.h"
     39 #include "llvm/MC/MCExpr.h"
     40 #include "llvm/MC/MCInst.h"
     41 #include "llvm/MC/MCSection.h"
     42 #include "llvm/MC/MCStreamer.h"
     43 #include "llvm/MC/MCSymbol.h"
     44 #include "llvm/Support/CommandLine.h"
     45 #include "llvm/Support/Compiler.h"
     46 #include "llvm/Support/Debug.h"
     47 #include "llvm/Support/Format.h"
     48 #include "llvm/Support/MathExtras.h"
     49 #include "llvm/Support/TargetRegistry.h"
     50 #include "llvm/Support/raw_ostream.h"
     51 #include "llvm/Target/TargetInstrInfo.h"
     52 #include "llvm/Target/TargetLoweringObjectFile.h"
     53 #include "llvm/Target/TargetOptions.h"
     54 #include "llvm/Target/TargetRegisterInfo.h"
     55 
     56 using namespace llvm;
     57 
     58 #define DEBUG_TYPE "asm-printer"
     59 
     60 static cl::opt<bool> AlignCalls(
     61          "hexagon-align-calls", cl::Hidden, cl::init(true),
     62           cl::desc("Insert falign after call instruction for Hexagon target"));
     63 
     64 void HexagonAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
     65                                     raw_ostream &O) {
     66   const MachineOperand &MO = MI->getOperand(OpNo);
     67 
     68   switch (MO.getType()) {
     69   default: llvm_unreachable ("<unknown operand type>");
     70   case MachineOperand::MO_Register:
     71     O << HexagonInstPrinter::getRegisterName(MO.getReg());
     72     return;
     73   case MachineOperand::MO_Immediate:
     74     O << MO.getImm();
     75     return;
     76   case MachineOperand::MO_MachineBasicBlock:
     77     O << *MO.getMBB()->getSymbol();
     78     return;
     79   case MachineOperand::MO_ConstantPoolIndex:
     80     O << *GetCPISymbol(MO.getIndex());
     81     return;
     82   case MachineOperand::MO_GlobalAddress:
     83     // Computing the address of a global symbol, not calling it.
     84     O << *getSymbol(MO.getGlobal());
     85     printOffset(MO.getOffset(), O);
     86     return;
     87   }
     88 }
     89 
     90 //
     91 // isBlockOnlyReachableByFallthrough - We need to override this since the
     92 // default AsmPrinter does not print labels for any basic block that
     93 // is only reachable by a fall through. That works for all cases except
     94 // for the case in which the basic block is reachable by a fall through but
     95 // through an indirect from a jump table. In this case, the jump table
     96 // will contain a label not defined by AsmPrinter.
     97 //
     98 bool HexagonAsmPrinter::
     99 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
    100   if (MBB->hasAddressTaken()) {
    101     return false;
    102   }
    103   return AsmPrinter::isBlockOnlyReachableByFallthrough(MBB);
    104 }
    105 
    106 
    107 /// PrintAsmOperand - Print out an operand for an inline asm expression.
    108 ///
    109 bool HexagonAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
    110                                         unsigned AsmVariant,
    111                                         const char *ExtraCode,
    112                                         raw_ostream &OS) {
    113   // Does this asm operand have a single letter operand modifier?
    114   if (ExtraCode && ExtraCode[0]) {
    115     if (ExtraCode[1] != 0) return true; // Unknown modifier.
    116 
    117     switch (ExtraCode[0]) {
    118     default:
    119       // See if this is a generic print operand
    120       return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
    121     case 'c': // Don't print "$" before a global var name or constant.
    122       // Hexagon never has a prefix.
    123       printOperand(MI, OpNo, OS);
    124       return false;
    125     case 'L': // Write second word of DImode reference.
    126       // Verify that this operand has two consecutive registers.
    127       if (!MI->getOperand(OpNo).isReg() ||
    128           OpNo+1 == MI->getNumOperands() ||
    129           !MI->getOperand(OpNo+1).isReg())
    130         return true;
    131       ++OpNo;   // Return the high-part.
    132       break;
    133     case 'I':
    134       // Write 'i' if an integer constant, otherwise nothing.  Used to print
    135       // addi vs add, etc.
    136       if (MI->getOperand(OpNo).isImm())
    137         OS << "i";
    138       return false;
    139     }
    140   }
    141 
    142   printOperand(MI, OpNo, OS);
    143   return false;
    144 }
    145 
    146 bool HexagonAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
    147                                             unsigned OpNo, unsigned AsmVariant,
    148                                             const char *ExtraCode,
    149                                             raw_ostream &O) {
    150   if (ExtraCode && ExtraCode[0])
    151     return true; // Unknown modifier.
    152 
    153   const MachineOperand &Base  = MI->getOperand(OpNo);
    154   const MachineOperand &Offset = MI->getOperand(OpNo+1);
    155 
    156   if (Base.isReg())
    157     printOperand(MI, OpNo, O);
    158   else
    159     llvm_unreachable("Unimplemented");
    160 
    161   if (Offset.isImm()) {
    162     if (Offset.getImm())
    163       O << " + #" << Offset.getImm();
    164   }
    165   else
    166     llvm_unreachable("Unimplemented");
    167 
    168   return false;
    169 }
    170 
    171 
    172 /// printMachineInstruction -- Print out a single Hexagon MI in Darwin syntax to
    173 /// the current output stream.
    174 ///
    175 void HexagonAsmPrinter::EmitInstruction(const MachineInstr *MI) {
    176   if (MI->isBundle()) {
    177     std::vector<const MachineInstr*> BundleMIs;
    178 
    179     const MachineBasicBlock *MBB = MI->getParent();
    180     MachineBasicBlock::const_instr_iterator MII = MI;
    181     ++MII;
    182     unsigned int IgnoreCount = 0;
    183     while (MII != MBB->end() && MII->isInsideBundle()) {
    184       const MachineInstr *MInst = MII;
    185       if (MInst->getOpcode() == TargetOpcode::DBG_VALUE ||
    186           MInst->getOpcode() == TargetOpcode::IMPLICIT_DEF) {
    187           IgnoreCount++;
    188           ++MII;
    189           continue;
    190       }
    191       //BundleMIs.push_back(&*MII);
    192       BundleMIs.push_back(MInst);
    193       ++MII;
    194     }
    195     unsigned Size = BundleMIs.size();
    196     assert((Size+IgnoreCount) == MI->getBundleSize() && "Corrupt Bundle!");
    197     for (unsigned Index = 0; Index < Size; Index++) {
    198       HexagonMCInst MCI;
    199       MCI.setPacketStart(Index == 0);
    200       MCI.setPacketEnd(Index == (Size-1));
    201 
    202       HexagonLowerToMC(BundleMIs[Index], MCI, *this);
    203       EmitToStreamer(OutStreamer, MCI);
    204     }
    205   }
    206   else {
    207     HexagonMCInst MCI;
    208     if (MI->getOpcode() == Hexagon::ENDLOOP0) {
    209       MCI.setPacketStart(true);
    210       MCI.setPacketEnd(true);
    211     }
    212     HexagonLowerToMC(MI, MCI, *this);
    213     EmitToStreamer(OutStreamer, MCI);
    214   }
    215 
    216   return;
    217 }
    218 
    219 static MCInstPrinter *createHexagonMCInstPrinter(const Target &T,
    220                                                  unsigned SyntaxVariant,
    221                                                  const MCAsmInfo &MAI,
    222                                                  const MCInstrInfo &MII,
    223                                                  const MCRegisterInfo &MRI,
    224                                                  const MCSubtargetInfo &STI) {
    225   if (SyntaxVariant == 0)
    226     return(new HexagonInstPrinter(MAI, MII, MRI));
    227   else
    228    return nullptr;
    229 }
    230 
    231 extern "C" void LLVMInitializeHexagonAsmPrinter() {
    232   RegisterAsmPrinter<HexagonAsmPrinter> X(TheHexagonTarget);
    233 
    234   TargetRegistry::RegisterMCInstPrinter(TheHexagonTarget,
    235                                         createHexagonMCInstPrinter);
    236 }
    237