lib/Target/X86/AsmPrinter/X86MCInstLower.cpp

   1 //===-- X86MCInstLower.cpp - Convert X86 MachineInstr to an MCInst --------===//
   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 code to lower X86 MachineInstrs to their corresponding
  11 // MCInst records.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "X86MCInstLower.h"
  16 #include "X86ATTAsmPrinter.h"
  17 #include "X86MCAsmInfo.h"
  18 #include "llvm/MC/MCContext.h"
  19 #include "llvm/MC/MCExpr.h"
  20 #include "llvm/MC/MCInst.h"
  21 #include "llvm/MC/MCStreamer.h"
  22 #include "llvm/Support/FormattedStream.h"
  23 #include "llvm/Support/Mangler.h"
  24 #include "llvm/ADT/SmallString.h"
  25 using namespace llvm;
  26
  27
  28 const X86Subtarget &X86MCInstLower::getSubtarget() const {
  29   return AsmPrinter.getSubtarget();
  30 }
  31
  32
  33 MCSymbol *X86MCInstLower::GetPICBaseSymbol() const {
  34   // FIXME: the actual label generated doesn't matter here!  Just mangle in
  35   // something unique (the function number) with Private prefix.
  36   SmallString<60> Name;
  37
  38   if (getSubtarget().isTargetDarwin()) {
  39     raw_svector_ostream(Name) << 'L' << AsmPrinter.getFunctionNumber() << "$pb";
  40   } else {
  41     assert(getSubtarget().isTargetELF() && "Don't know how to print PIC label!");
  42     raw_svector_ostream(Name) << ".Lllvm$" << AsmPrinter.getFunctionNumber()
  43        << ".$piclabel";
  44   }
  45   return Ctx.GetOrCreateSymbol(Name.str());
  46 }
  47
  48
  49 /// LowerGlobalAddressOperand - Lower an MO_GlobalAddress operand to an
  50 /// MCOperand.
  51 MCSymbol *X86MCInstLower::
  52 GetGlobalAddressSymbol(const MachineOperand &MO) const {
  53   const GlobalValue *GV = MO.getGlobal();
  54
  55   bool isImplicitlyPrivate = false;
  56   if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB ||
  57       MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
  58       MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
  59       MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
  60     isImplicitlyPrivate = true;
  61
  62   SmallString<128> Name;
  63   Mang->getNameWithPrefix(Name, GV, isImplicitlyPrivate);
  64
  65   if (getSubtarget().isTargetCygMing())
  66     AsmPrinter.DecorateCygMingName(Name, GV);
  67
  68   switch (MO.getTargetFlags()) {
  69   default: llvm_unreachable("Unknown target flag on GV operand");
  70   case X86II::MO_NO_FLAG:                // No flag.
  71   case X86II::MO_GOT_ABSOLUTE_ADDRESS:   // Doesn't modify symbol name.
  72   case X86II::MO_PIC_BASE_OFFSET:        // Doesn't modify symbol name.
  73     break;
  74   case X86II::MO_DLLIMPORT: {
  75     // Handle dllimport linkage.
  76     const char *Prefix = "__imp_";
  77     Name.insert(Name.begin(), Prefix, Prefix+strlen(Prefix));
  78     break;
  79   }
  80   case X86II::MO_DARWIN_NONLAZY:
  81   case X86II::MO_DARWIN_NONLAZY_PIC_BASE: {
  82     Name += "$non_lazy_ptr";
  83     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
  84     MCSymbol *&StubSym = AsmPrinter.GVStubs[Sym];
  85     if (StubSym == 0) {
  86       Name.clear();
  87       Mang->getNameWithPrefix(Name, GV, false);
  88       StubSym = Ctx.GetOrCreateSymbol(Name.str());
  89     }
  90     return Sym;
  91   }
  92   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE: {
  93     Name += "$non_lazy_ptr";
  94     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
  95     MCSymbol *&StubSym = AsmPrinter.HiddenGVStubs[Sym];
  96     if (StubSym == 0) {
  97       Name.clear();
  98       Mang->getNameWithPrefix(Name, GV, false);
  99       StubSym = Ctx.GetOrCreateSymbol(Name.str());
 100     }
 101     return Sym;
 102   }
 103   case X86II::MO_DARWIN_STUB: {
 104     Name += "$stub";
 105     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
 106     MCSymbol *&StubSym = AsmPrinter.FnStubs[Sym];
 107     if (StubSym == 0) {
 108       Name.clear();
 109       Mang->getNameWithPrefix(Name, GV, false);
 110       StubSym = Ctx.GetOrCreateSymbol(Name.str());
 111     }
 112     return Sym;
 113   }
 114   // FIXME: These probably should be a modifier on the symbol or something??
 115   case X86II::MO_TLSGD:     Name += "@TLSGD";     break;
 116   case X86II::MO_GOTTPOFF:  Name += "@GOTTPOFF";  break;
 117   case X86II::MO_INDNTPOFF: Name += "@INDNTPOFF"; break;
 118   case X86II::MO_TPOFF:     Name += "@TPOFF";     break;
 119   case X86II::MO_NTPOFF:    Name += "@NTPOFF";    break;
 120   case X86II::MO_GOTPCREL:  Name += "@GOTPCREL";  break;
 121   case X86II::MO_GOT:       Name += "@GOT";       break;
 122   case X86II::MO_GOTOFF:    Name += "@GOTOFF";    break;
 123   case X86II::MO_PLT:       Name += "@PLT";       break;
 124   }
 125
 126   return Ctx.GetOrCreateSymbol(Name.str());
 127 }
 128
 129 MCSymbol *X86MCInstLower::
 130 GetExternalSymbolSymbol(const MachineOperand &MO) const {
 131   SmallString<128> Name;
 132   Name += AsmPrinter.MAI->getGlobalPrefix();
 133   Name += MO.getSymbolName();
 134
 135   switch (MO.getTargetFlags()) {
 136   default: llvm_unreachable("Unknown target flag on GV operand");
 137   case X86II::MO_NO_FLAG:                // No flag.
 138   case X86II::MO_GOT_ABSOLUTE_ADDRESS:   // Doesn't modify symbol name.
 139   case X86II::MO_PIC_BASE_OFFSET:        // Doesn't modify symbol name.
 140     break;
 141   case X86II::MO_DLLIMPORT: {
 142     // Handle dllimport linkage.
 143     const char *Prefix = "__imp_";
 144     Name.insert(Name.begin(), Prefix, Prefix+strlen(Prefix));
 145     break;
 146   }
 147   case X86II::MO_DARWIN_STUB: {
 148     Name += "$stub";
 149     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
 150     MCSymbol *&StubSym = AsmPrinter.FnStubs[Sym];
 151     if (StubSym == 0) {
 152       Name.erase(Name.end()-5, Name.end());
 153       StubSym = Ctx.GetOrCreateSymbol(Name.str());
 154     }
 155     return Sym;
 156   }
 157   // FIXME: These probably should be a modifier on the symbol or something??
 158   case X86II::MO_TLSGD:     Name += "@TLSGD";     break;
 159   case X86II::MO_GOTTPOFF:  Name += "@GOTTPOFF";  break;
 160   case X86II::MO_INDNTPOFF: Name += "@INDNTPOFF"; break;
 161   case X86II::MO_TPOFF:     Name += "@TPOFF";     break;
 162   case X86II::MO_NTPOFF:    Name += "@NTPOFF";    break;
 163   case X86II::MO_GOTPCREL:  Name += "@GOTPCREL";  break;
 164   case X86II::MO_GOT:       Name += "@GOT";       break;
 165   case X86II::MO_GOTOFF:    Name += "@GOTOFF";    break;
 166   case X86II::MO_PLT:       Name += "@PLT";       break;
 167   }
 168
 169   return Ctx.GetOrCreateSymbol(Name.str());
 170 }
 171
 172 MCSymbol *X86MCInstLower::GetJumpTableSymbol(const MachineOperand &MO) const {
 173   SmallString<256> Name;
 174   raw_svector_ostream(Name) << AsmPrinter.MAI->getPrivateGlobalPrefix() << "JTI"
 175     << AsmPrinter.getFunctionNumber() << '_' << MO.getIndex();
 176
 177   switch (MO.getTargetFlags()) {
 178   default:
 179     llvm_unreachable("Unknown target flag on GV operand");
 180   case X86II::MO_NO_FLAG:    // No flag.
 181   case X86II::MO_PIC_BASE_OFFSET:
 182   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
 183   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
 184     break;
 185     // FIXME: These probably should be a modifier on the symbol or something??
 186   case X86II::MO_TLSGD:     Name += "@TLSGD";     break;
 187   case X86II::MO_GOTTPOFF:  Name += "@GOTTPOFF";  break;
 188   case X86II::MO_INDNTPOFF: Name += "@INDNTPOFF"; break;
 189   case X86II::MO_TPOFF:     Name += "@TPOFF";     break;
 190   case X86II::MO_NTPOFF:    Name += "@NTPOFF";    break;
 191   case X86II::MO_GOTPCREL:  Name += "@GOTPCREL";  break;
 192   case X86II::MO_GOT:       Name += "@GOT";       break;
 193   case X86II::MO_GOTOFF:    Name += "@GOTOFF";    break;
 194   case X86II::MO_PLT:       Name += "@PLT";       break;
 195   }
 196
 197   // Create a symbol for the name.
 198   return Ctx.GetOrCreateSymbol(Name.str());
 199 }
 200
 201
 202 MCSymbol *X86MCInstLower::
 203 GetConstantPoolIndexSymbol(const MachineOperand &MO) const {
 204   SmallString<256> Name;
 205   raw_svector_ostream(Name) << AsmPrinter.MAI->getPrivateGlobalPrefix() << "CPI"
 206     << AsmPrinter.getFunctionNumber() << '_' << MO.getIndex();
 207
 208   switch (MO.getTargetFlags()) {
 209   default:
 210     llvm_unreachable("Unknown target flag on GV operand");
 211   case X86II::MO_NO_FLAG:    // No flag.
 212   case X86II::MO_PIC_BASE_OFFSET:
 213   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
 214   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
 215     break;
 216     // FIXME: These probably should be a modifier on the symbol or something??
 217   case X86II::MO_TLSGD:     Name += "@TLSGD";     break;
 218   case X86II::MO_GOTTPOFF:  Name += "@GOTTPOFF";  break;
 219   case X86II::MO_INDNTPOFF: Name += "@INDNTPOFF"; break;
 220   case X86II::MO_TPOFF:     Name += "@TPOFF";     break;
 221   case X86II::MO_NTPOFF:    Name += "@NTPOFF";    break;
 222   case X86II::MO_GOTPCREL:  Name += "@GOTPCREL";  break;
 223   case X86II::MO_GOT:       Name += "@GOT";       break;
 224   case X86II::MO_GOTOFF:    Name += "@GOTOFF";    break;
 225   case X86II::MO_PLT:       Name += "@PLT";       break;
 226   }
 227
 228   // Create a symbol for the name.
 229   return Ctx.GetOrCreateSymbol(Name.str());
 230 }
 231
 232 MCOperand X86MCInstLower::LowerSymbolOperand(const MachineOperand &MO,
 233                                              MCSymbol *Sym) const {
 234   // FIXME: We would like an efficient form for this, so we don't have to do a
 235   // lot of extra uniquing.
 236   const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
 237
 238   switch (MO.getTargetFlags()) {
 239   default: llvm_unreachable("Unknown target flag on GV operand");
 240   case X86II::MO_NO_FLAG:    // No flag.
 241
 242   // These affect the name of the symbol, not any suffix.
 243   case X86II::MO_DARWIN_NONLAZY:
 244   case X86II::MO_DLLIMPORT:
 245   case X86II::MO_DARWIN_STUB:
 246   case X86II::MO_TLSGD:
 247   case X86II::MO_GOTTPOFF:
 248   case X86II::MO_INDNTPOFF:
 249   case X86II::MO_TPOFF:
 250   case X86II::MO_NTPOFF:
 251   case X86II::MO_GOTPCREL:
 252   case X86II::MO_GOT:
 253   case X86II::MO_GOTOFF:
 254   case X86II::MO_PLT:
 255     break;
 256   case X86II::MO_PIC_BASE_OFFSET:
 257   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
 258   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
 259     // Subtract the pic base.
 260     Expr = MCBinaryExpr::CreateSub(Expr,
 261                                    MCSymbolRefExpr::Create(GetPICBaseSymbol(),
 262                                                            Ctx),
 263                                    Ctx);
 264     break;
 265   case X86II::MO_GOT_ABSOLUTE_ADDRESS: {
 266     // For this, we want to print something like:
 267     //   MYSYMBOL + (. - PICBASE)
 268     // However, we can't generate a ".", so just emit a new label here and refer
 269     // to it.  We know that this operand flag occurs at most once per function.
 270     SmallString<64> Name;
 271     raw_svector_ostream(Name) << AsmPrinter.MAI->getPrivateGlobalPrefix()
 272       << "picbaseref" << AsmPrinter.getFunctionNumber();
 273     MCSymbol *DotSym = Ctx.GetOrCreateSymbol(Name.str());
 274 // FIXME: This instruction should be lowered before we get here...
 275     AsmPrinter.OutStreamer.EmitLabel(DotSym);
 276
 277     const MCExpr *DotExpr = MCSymbolRefExpr::Create(DotSym, Ctx);
 278     const MCExpr *PICBase = MCSymbolRefExpr::Create(GetPICBaseSymbol(),
 279                                                     Ctx);
 280     DotExpr = MCBinaryExpr::CreateSub(DotExpr, PICBase, Ctx);
 281     Expr = MCBinaryExpr::CreateAdd(Expr, DotExpr, Ctx);
 282     break;
 283   }
 284   }
 285
 286   if (!MO.isJTI() && MO.getOffset())
 287     Expr = MCBinaryExpr::CreateAdd(Expr,
 288                                    MCConstantExpr::Create(MO.getOffset(), Ctx),
 289                                    Ctx);
 290   return MCOperand::CreateExpr(Expr);
 291 }
 292
 293
 294
 295 static void lower_subreg32(MCInst *MI, unsigned OpNo) {
 296   // Convert registers in the addr mode according to subreg32.
 297   unsigned Reg = MI->getOperand(OpNo).getReg();
 298   if (Reg != 0)
 299     MI->getOperand(OpNo).setReg(getX86SubSuperRegister(Reg, MVT::i32));
 300 }
 301
 302 static void lower_lea64_32mem(MCInst *MI, unsigned OpNo) {
 303   // Convert registers in the addr mode according to subreg64.
 304   for (unsigned i = 0; i != 4; ++i) {
 305     if (!MI->getOperand(OpNo+i).isReg()) continue;
 306
 307     unsigned Reg = MI->getOperand(OpNo+i).getReg();
 308     if (Reg == 0) continue;
 309
 310     MI->getOperand(OpNo+i).setReg(getX86SubSuperRegister(Reg, MVT::i64));
 311   }
 312 }
 313
 314
 315
 316 void X86MCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
 317   OutMI.setOpcode(MI->getOpcode());
 318
 319   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
 320     const MachineOperand &MO = MI->getOperand(i);
 321
 322     MCOperand MCOp;
 323     switch (MO.getType()) {
 324     default:
 325       MI->dump();
 326       llvm_unreachable("unknown operand type");
 327     case MachineOperand::MO_Register:
 328       MCOp = MCOperand::CreateReg(MO.getReg());
 329       break;
 330     case MachineOperand::MO_Immediate:
 331       MCOp = MCOperand::CreateImm(MO.getImm());
 332       break;
 333     case MachineOperand::MO_MachineBasicBlock:
 334 // FIXME: Kill MBBLabel operand type!
 335       MCOp = MCOperand::CreateMBBLabel(AsmPrinter.getFunctionNumber(),
 336                                        MO.getMBB()->getNumber());
 337       break;
 338     case MachineOperand::MO_GlobalAddress:
 339       MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
 340       break;
 341     case MachineOperand::MO_ExternalSymbol:
 342       MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
 343       break;
 344     case MachineOperand::MO_JumpTableIndex:
 345       MCOp = LowerSymbolOperand(MO, GetJumpTableSymbol(MO));
 346       break;
 347     case MachineOperand::MO_ConstantPoolIndex:
 348       MCOp = LowerSymbolOperand(MO, GetConstantPoolIndexSymbol(MO));
 349       break;
 350     }
 351
 352     OutMI.addOperand(MCOp);
 353   }
 354
 355   // Handle a few special cases to eliminate operand modifiers.
 356   switch (OutMI.getOpcode()) {
 357   case X86::LEA64_32r: // Handle 'subreg rewriting' for the lea64_32mem operand.
 358     lower_lea64_32mem(&OutMI, 1);
 359     break;
 360   case X86::MOV16r0:
 361     OutMI.setOpcode(X86::MOV32r0);
 362     lower_subreg32(&OutMI, 0);
 363     break;
 364   case X86::MOVZX16rr8:
 365     OutMI.setOpcode(X86::MOVZX32rr8);
 366     lower_subreg32(&OutMI, 0);
 367     break;
 368   case X86::MOVZX16rm8:
 369     OutMI.setOpcode(X86::MOVZX32rm8);
 370     lower_subreg32(&OutMI, 0);
 371     break;
 372   case X86::MOVSX16rr8:
 373     OutMI.setOpcode(X86::MOVSX32rr8);
 374     lower_subreg32(&OutMI, 0);
 375     break;
 376   case X86::MOVSX16rm8:
 377     OutMI.setOpcode(X86::MOVSX32rm8);
 378     lower_subreg32(&OutMI, 0);
 379     break;
 380   case X86::MOVZX64rr32:
 381     OutMI.setOpcode(X86::MOV32rr);
 382     lower_subreg32(&OutMI, 0);
 383     break;
 384   case X86::MOVZX64rm32:
 385     OutMI.setOpcode(X86::MOV32rm);
 386     lower_subreg32(&OutMI, 0);
 387     break;
 388   case X86::MOV64ri64i32:
 389     OutMI.setOpcode(X86::MOV32ri);
 390     lower_subreg32(&OutMI, 0);
 391     break;
 392   case X86::MOVZX64rr8:
 393     OutMI.setOpcode(X86::MOVZX32rr8);
 394     lower_subreg32(&OutMI, 0);
 395     break;
 396   case X86::MOVZX64rm8:
 397     OutMI.setOpcode(X86::MOVZX32rm8);
 398     lower_subreg32(&OutMI, 0);
 399     break;
 400   case X86::MOVZX64rr16:
 401     OutMI.setOpcode(X86::MOVZX32rr16);
 402     lower_subreg32(&OutMI, 0);
 403     break;
 404   case X86::MOVZX64rm16:
 405     OutMI.setOpcode(X86::MOVZX32rm16);
 406     lower_subreg32(&OutMI, 0);
 407     break;
 408   }
 409 }
 410
 411
 412
 413 void X86ATTAsmPrinter::
 414 printInstructionThroughMCStreamer(const MachineInstr *MI) {
 415   X86MCInstLower MCInstLowering(OutContext, Mang, *this);
 416   switch (MI->getOpcode()) {
 417   case TargetInstrInfo::DBG_LABEL:
 418   case TargetInstrInfo::EH_LABEL:
 419   case TargetInstrInfo::GC_LABEL:
 420     printLabel(MI);
 421     return;
 422   case TargetInstrInfo::INLINEASM:
 423     O << '\t';
 424     printInlineAsm(MI);
 425     return;
 426   case TargetInstrInfo::IMPLICIT_DEF:
 427     printImplicitDef(MI);
 428     return;
 429   case X86::MOVPC32r: {
 430     MCInst TmpInst;
 431     // This is a pseudo op for a two instruction sequence with a label, which
 432     // looks like:
 433     //     call "L1$pb"
 434     // "L1$pb":
 435     //     popl %esi
 436
 437     // Emit the call.
 438     MCSymbol *PICBase = MCInstLowering.GetPICBaseSymbol();
 439     TmpInst.setOpcode(X86::CALLpcrel32);
 440     // FIXME: We would like an efficient form for this, so we don't have to do a
 441     // lot of extra uniquing.
 442     TmpInst.addOperand(MCOperand::CreateExpr(MCSymbolRefExpr::Create(PICBase,
 443                                                                  OutContext)));
 444     printInstruction(&TmpInst);
 445     O << '\n';
 446
 447     // Emit the label.
 448     OutStreamer.EmitLabel(PICBase);
 449
 450     // popl $reg
 451     TmpInst.setOpcode(X86::POP32r);
 452     TmpInst.getOperand(0) = MCOperand::CreateReg(MI->getOperand(0).getReg());
 453     printInstruction(&TmpInst);
 454     return;
 455     }
 456   }
 457
 458   MCInst TmpInst;
 459   MCInstLowering.Lower(MI, TmpInst);
 460
 461
 462   printInstruction(&TmpInst);
 463 }