lib/Target/Lanai/LanaiAsmPrinter.cpp

   1 //===-- LanaiAsmPrinter.cpp - Lanai LLVM assembly writer ------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file contains a printer that converts from our internal representation
  10 // of machine-dependent LLVM code to the Lanai assembly language.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "MCTargetDesc/LanaiInstPrinter.h"
  15 #include "LanaiAluCode.h"
  16 #include "LanaiCondCode.h"
  17 #include "LanaiInstrInfo.h"
  18 #include "LanaiMCInstLower.h"
  19 #include "LanaiTargetMachine.h"
  20 #include "TargetInfo/LanaiTargetInfo.h"
  21 #include "llvm/CodeGen/AsmPrinter.h"
  22 #include "llvm/CodeGen/MachineConstantPool.h"
  23 #include "llvm/CodeGen/MachineFunctionPass.h"
  24 #include "llvm/CodeGen/MachineInstr.h"
  25 #include "llvm/CodeGen/MachineModuleInfo.h"
  26 #include "llvm/IR/Constants.h"
  27 #include "llvm/IR/DerivedTypes.h"
  28 #include "llvm/IR/Mangler.h"
  29 #include "llvm/IR/Module.h"
  30 #include "llvm/MC/MCAsmInfo.h"
  31 #include "llvm/MC/MCInst.h"
  32 #include "llvm/MC/MCInstBuilder.h"
  33 #include "llvm/MC/MCStreamer.h"
  34 #include "llvm/MC/MCSymbol.h"
  35 #include "llvm/Support/TargetRegistry.h"
  36 #include "llvm/Support/raw_ostream.h"
  37
  38 #define DEBUG_TYPE "asm-printer"
  39
  40 using namespace llvm;
  41
  42 namespace {
  43 class LanaiAsmPrinter : public AsmPrinter {
  44 public:
  45   explicit LanaiAsmPrinter(TargetMachine &TM,
  46                            std::unique_ptr<MCStreamer> Streamer)
  47       : AsmPrinter(TM, std::move(Streamer)) {}
  48
  49   StringRef getPassName() const override { return "Lanai Assembly Printer"; }
  50
  51   void printOperand(const MachineInstr *MI, int OpNum, raw_ostream &O);
  52   bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
  53                        const char *ExtraCode, raw_ostream &O) override;
  54   void EmitInstruction(const MachineInstr *MI) override;
  55   bool isBlockOnlyReachableByFallthrough(
  56       const MachineBasicBlock *MBB) const override;
  57
  58 private:
  59   void customEmitInstruction(const MachineInstr *MI);
  60   void emitCallInstruction(const MachineInstr *MI);
  61 };
  62 } // end of anonymous namespace
  63
  64 void LanaiAsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
  65                                    raw_ostream &O) {
  66   const MachineOperand &MO = MI->getOperand(OpNum);
  67
  68   switch (MO.getType()) {
  69   case MachineOperand::MO_Register:
  70     O << LanaiInstPrinter::getRegisterName(MO.getReg());
  71     break;
  72
  73   case MachineOperand::MO_Immediate:
  74     O << MO.getImm();
  75     break;
  76
  77   case MachineOperand::MO_MachineBasicBlock:
  78     O << *MO.getMBB()->getSymbol();
  79     break;
  80
  81   case MachineOperand::MO_GlobalAddress:
  82     O << *getSymbol(MO.getGlobal());
  83     break;
  84
  85   case MachineOperand::MO_BlockAddress: {
  86     MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress());
  87     O << BA->getName();
  88     break;
  89   }
  90
  91   case MachineOperand::MO_ExternalSymbol:
  92     O << *GetExternalSymbolSymbol(MO.getSymbolName());
  93     break;
  94
  95   case MachineOperand::MO_JumpTableIndex:
  96     O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() << '_'
  97       << MO.getIndex();
  98     break;
  99
 100   case MachineOperand::MO_ConstantPoolIndex:
 101     O << MAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
 102       << MO.getIndex();
 103     return;
 104
 105   default:
 106     llvm_unreachable("<unknown operand type>");
 107   }
 108 }
 109
 110 // PrintAsmOperand - Print out an operand for an inline asm expression.
 111 bool LanaiAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
 112                                       const char *ExtraCode, raw_ostream &O) {
 113   // Does this asm operand have a single letter operand modifier?
 114   if (ExtraCode && ExtraCode[0]) {
 115     if (ExtraCode[1])
 116       return true; // Unknown modifier.
 117
 118     switch (ExtraCode[0]) {
 119     // The highest-numbered register of a pair.
 120     case 'H': {
 121       if (OpNo == 0)
 122         return true;
 123       const MachineOperand &FlagsOP = MI->getOperand(OpNo - 1);
 124       if (!FlagsOP.isImm())
 125         return true;
 126       unsigned Flags = FlagsOP.getImm();
 127       unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
 128       if (NumVals != 2)
 129         return true;
 130       unsigned RegOp = OpNo + 1;
 131       if (RegOp >= MI->getNumOperands())
 132         return true;
 133       const MachineOperand &MO = MI->getOperand(RegOp);
 134       if (!MO.isReg())
 135         return true;
 136       unsigned Reg = MO.getReg();
 137       O << LanaiInstPrinter::getRegisterName(Reg);
 138       return false;
 139     }
 140     default:
 141       return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O);
 142     }
 143   }
 144   printOperand(MI, OpNo, O);
 145   return false;
 146 }
 147
 148 //===----------------------------------------------------------------------===//
 149 void LanaiAsmPrinter::emitCallInstruction(const MachineInstr *MI) {
 150   assert((MI->getOpcode() == Lanai::CALL || MI->getOpcode() == Lanai::CALLR) &&
 151          "Unsupported call function");
 152
 153   LanaiMCInstLower MCInstLowering(OutContext, *this);
 154   MCSubtargetInfo STI = getSubtargetInfo();
 155   // Insert save rca instruction immediately before the call.
 156   // TODO: We should generate a pc-relative mov instruction here instead
 157   // of pc + 16 (should be mov .+16 %rca).
 158   OutStreamer->EmitInstruction(MCInstBuilder(Lanai::ADD_I_LO)
 159                                    .addReg(Lanai::RCA)
 160                                    .addReg(Lanai::PC)
 161                                    .addImm(16),
 162                                STI);
 163
 164   // Push rca onto the stack.
 165   //   st %rca, [--%sp]
 166   OutStreamer->EmitInstruction(MCInstBuilder(Lanai::SW_RI)
 167                                    .addReg(Lanai::RCA)
 168                                    .addReg(Lanai::SP)
 169                                    .addImm(-4)
 170                                    .addImm(LPAC::makePreOp(LPAC::ADD)),
 171                                STI);
 172
 173   // Lower the call instruction.
 174   if (MI->getOpcode() == Lanai::CALL) {
 175     MCInst TmpInst;
 176     MCInstLowering.Lower(MI, TmpInst);
 177     TmpInst.setOpcode(Lanai::BT);
 178     OutStreamer->EmitInstruction(TmpInst, STI);
 179   } else {
 180     OutStreamer->EmitInstruction(MCInstBuilder(Lanai::ADD_R)
 181                                      .addReg(Lanai::PC)
 182                                      .addReg(MI->getOperand(0).getReg())
 183                                      .addReg(Lanai::R0)
 184                                      .addImm(LPCC::ICC_T),
 185                                  STI);
 186   }
 187 }
 188
 189 void LanaiAsmPrinter::customEmitInstruction(const MachineInstr *MI) {
 190   LanaiMCInstLower MCInstLowering(OutContext, *this);
 191   MCSubtargetInfo STI = getSubtargetInfo();
 192   MCInst TmpInst;
 193   MCInstLowering.Lower(MI, TmpInst);
 194   OutStreamer->EmitInstruction(TmpInst, STI);
 195 }
 196
 197 void LanaiAsmPrinter::EmitInstruction(const MachineInstr *MI) {
 198   MachineBasicBlock::const_instr_iterator I = MI->getIterator();
 199   MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();
 200
 201   do {
 202     if (I->isCall()) {
 203       emitCallInstruction(&*I);
 204       continue;
 205     }
 206
 207     customEmitInstruction(&*I);
 208   } while ((++I != E) && I->isInsideBundle());
 209 }
 210
 211 // isBlockOnlyReachableByFallthough - Return true if the basic block has
 212 // exactly one predecessor and the control transfer mechanism between
 213 // the predecessor and this block is a fall-through.
 214 // FIXME: could the overridden cases be handled in AnalyzeBranch?
 215 bool LanaiAsmPrinter::isBlockOnlyReachableByFallthrough(
 216     const MachineBasicBlock *MBB) const {
 217   // The predecessor has to be immediately before this block.
 218   const MachineBasicBlock *Pred = *MBB->pred_begin();
 219
 220   // If the predecessor is a switch statement, assume a jump table
 221   // implementation, so it is not a fall through.
 222   if (const BasicBlock *B = Pred->getBasicBlock())
 223     if (isa<SwitchInst>(B->getTerminator()))
 224       return false;
 225
 226   // Check default implementation
 227   if (!AsmPrinter::isBlockOnlyReachableByFallthrough(MBB))
 228     return false;
 229
 230   // Otherwise, check the last instruction.
 231   // Check if the last terminator is an unconditional branch.
 232   MachineBasicBlock::const_iterator I = Pred->end();
 233   while (I != Pred->begin() && !(--I)->isTerminator()) {
 234   }
 235
 236   return !I->isBarrier();
 237 }
 238
 239 // Force static initialization.
 240 extern "C" void LLVMInitializeLanaiAsmPrinter() {
 241   RegisterAsmPrinter<LanaiAsmPrinter> X(getTheLanaiTarget());
 242 }