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   SmallString<60> Name;
  35   raw_svector_ostream(Name) << AsmPrinter.MAI->getPrivateGlobalPrefix()
  36     << AsmPrinter.getFunctionNumber() << "$pb";
  37   return Ctx.GetOrCreateSymbol(Name.str());
  38 }
  39
  40
  41 /// LowerGlobalAddressOperand - Lower an MO_GlobalAddress operand to an
  42 /// MCOperand.
  43 MCSymbol *X86MCInstLower::
  44 GetGlobalAddressSymbol(const MachineOperand &MO) const {
  45   const GlobalValue *GV = MO.getGlobal();
  46
  47   bool isImplicitlyPrivate = false;
  48   if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB ||
  49       MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
  50       MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
  51       MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
  52     isImplicitlyPrivate = true;
  53
  54   SmallString<128> Name;
  55   Mang->getNameWithPrefix(Name, GV, isImplicitlyPrivate);
  56
  57   if (getSubtarget().isTargetCygMing())
  58     AsmPrinter.DecorateCygMingName(Name, GV);
  59
  60   switch (MO.getTargetFlags()) {
  61   default: llvm_unreachable("Unknown target flag on GV operand");
  62   case X86II::MO_NO_FLAG:                // No flag.
  63   case X86II::MO_PIC_BASE_OFFSET:        // Doesn't modify symbol name.
  64     break;
  65   case X86II::MO_DLLIMPORT: {
  66     // Handle dllimport linkage.
  67     const char *Prefix = "__imp_";
  68     Name.insert(Name.begin(), Prefix, Prefix+strlen(Prefix));
  69     break;
  70   }
  71   case X86II::MO_DARWIN_NONLAZY:
  72   case X86II::MO_DARWIN_NONLAZY_PIC_BASE: {
  73     Name += "$non_lazy_ptr";
  74     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
  75     MCSymbol *&StubSym = AsmPrinter.GVStubs[Sym];
  76     if (StubSym == 0) {
  77       Name.clear();
  78       Mang->getNameWithPrefix(Name, GV, false);
  79       StubSym = Ctx.GetOrCreateSymbol(Name.str());
  80     }
  81     return Sym;
  82   }
  83   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE: {
  84     Name += "$non_lazy_ptr";
  85     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
  86     MCSymbol *&StubSym = AsmPrinter.HiddenGVStubs[Sym];
  87     if (StubSym == 0) {
  88       Name.clear();
  89       Mang->getNameWithPrefix(Name, GV, false);
  90       StubSym = Ctx.GetOrCreateSymbol(Name.str());
  91     }
  92     return Sym;
  93   }
  94   case X86II::MO_DARWIN_STUB: {
  95     Name += "$stub";
  96     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
  97     MCSymbol *&StubSym = AsmPrinter.FnStubs[Sym];
  98     if (StubSym == 0) {
  99       Name.clear();
 100       Mang->getNameWithPrefix(Name, GV, false);
 101       StubSym = Ctx.GetOrCreateSymbol(Name.str());
 102     }
 103     return Sym;
 104   }
 105   // FIXME: These probably should be a modifier on the symbol or something??
 106   case X86II::MO_TLSGD:     Name += "@TLSGD";     break;
 107   case X86II::MO_GOTTPOFF:  Name += "@GOTTPOFF";  break;
 108   case X86II::MO_INDNTPOFF: Name += "@INDNTPOFF"; break;
 109   case X86II::MO_TPOFF:     Name += "@TPOFF";     break;
 110   case X86II::MO_NTPOFF:    Name += "@NTPOFF";    break;
 111   case X86II::MO_GOTPCREL:  Name += "@GOTPCREL";  break;
 112   case X86II::MO_GOT:       Name += "@GOT";       break;
 113   case X86II::MO_GOTOFF:    Name += "@GOTOFF";    break;
 114   case X86II::MO_PLT:       Name += "@PLT";       break;
 115   }
 116
 117   return Ctx.GetOrCreateSymbol(Name.str());
 118 }
 119
 120 MCSymbol *X86MCInstLower::
 121 GetExternalSymbolSymbol(const MachineOperand &MO) const {
 122   SmallString<128> Name;
 123   Name += AsmPrinter.MAI->getGlobalPrefix();
 124   Name += MO.getSymbolName();
 125
 126   switch (MO.getTargetFlags()) {
 127   default: llvm_unreachable("Unknown target flag on GV operand");
 128   case X86II::MO_NO_FLAG:                // No flag.
 129   case X86II::MO_GOT_ABSOLUTE_ADDRESS:   // Doesn't modify symbol name.
 130   case X86II::MO_PIC_BASE_OFFSET:        // Doesn't modify symbol name.
 131     break;
 132   case X86II::MO_DLLIMPORT: {
 133     // Handle dllimport linkage.
 134     const char *Prefix = "__imp_";
 135     Name.insert(Name.begin(), Prefix, Prefix+strlen(Prefix));
 136     break;
 137   }
 138   case X86II::MO_DARWIN_STUB: {
 139     Name += "$stub";
 140     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
 141     MCSymbol *&StubSym = AsmPrinter.FnStubs[Sym];
 142     if (StubSym == 0) {
 143       Name.erase(Name.end()-5, Name.end());
 144       StubSym = Ctx.GetOrCreateSymbol(Name.str());
 145     }
 146     return Sym;
 147   }
 148   // FIXME: These probably should be a modifier on the symbol or something??
 149   case X86II::MO_TLSGD:     Name += "@TLSGD";     break;
 150   case X86II::MO_GOTTPOFF:  Name += "@GOTTPOFF";  break;
 151   case X86II::MO_INDNTPOFF: Name += "@INDNTPOFF"; break;
 152   case X86II::MO_TPOFF:     Name += "@TPOFF";     break;
 153   case X86II::MO_NTPOFF:    Name += "@NTPOFF";    break;
 154   case X86II::MO_GOTPCREL:  Name += "@GOTPCREL";  break;
 155   case X86II::MO_GOT:       Name += "@GOT";       break;
 156   case X86II::MO_GOTOFF:    Name += "@GOTOFF";    break;
 157   case X86II::MO_PLT:       Name += "@PLT";       break;
 158   }
 159
 160   return Ctx.GetOrCreateSymbol(Name.str());
 161 }
 162
 163 MCSymbol *X86MCInstLower::GetJumpTableSymbol(const MachineOperand &MO) const {
 164   SmallString<256> Name;
 165   raw_svector_ostream(Name) << AsmPrinter.MAI->getPrivateGlobalPrefix() << "JTI"
 166     << AsmPrinter.getFunctionNumber() << '_' << MO.getIndex();
 167
 168   switch (MO.getTargetFlags()) {
 169   default:
 170     llvm_unreachable("Unknown target flag on GV operand");
 171   case X86II::MO_NO_FLAG:    // No flag.
 172   case X86II::MO_PIC_BASE_OFFSET:
 173   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
 174   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
 175     break;
 176     // FIXME: These probably should be a modifier on the symbol or something??
 177   case X86II::MO_TLSGD:     Name += "@TLSGD";     break;
 178   case X86II::MO_GOTTPOFF:  Name += "@GOTTPOFF";  break;
 179   case X86II::MO_INDNTPOFF: Name += "@INDNTPOFF"; break;
 180   case X86II::MO_TPOFF:     Name += "@TPOFF";     break;
 181   case X86II::MO_NTPOFF:    Name += "@NTPOFF";    break;
 182   case X86II::MO_GOTPCREL:  Name += "@GOTPCREL";  break;
 183   case X86II::MO_GOT:       Name += "@GOT";       break;
 184   case X86II::MO_GOTOFF:    Name += "@GOTOFF";    break;
 185   case X86II::MO_PLT:       Name += "@PLT";       break;
 186   }
 187
 188   // Create a symbol for the name.
 189   return Ctx.GetOrCreateSymbol(Name.str());
 190 }
 191
 192
 193 MCSymbol *X86MCInstLower::
 194 GetConstantPoolIndexSymbol(const MachineOperand &MO) const {
 195   SmallString<256> Name;
 196   raw_svector_ostream(Name) << AsmPrinter.MAI->getPrivateGlobalPrefix() << "CPI"
 197     << AsmPrinter.getFunctionNumber() << '_' << MO.getIndex();
 198
 199   switch (MO.getTargetFlags()) {
 200   default:
 201     llvm_unreachable("Unknown target flag on GV operand");
 202   case X86II::MO_NO_FLAG:    // No flag.
 203   case X86II::MO_PIC_BASE_OFFSET:
 204   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
 205   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
 206     break;
 207     // FIXME: These probably should be a modifier on the symbol or something??
 208   case X86II::MO_TLSGD:     Name += "@TLSGD";     break;
 209   case X86II::MO_GOTTPOFF:  Name += "@GOTTPOFF";  break;
 210   case X86II::MO_INDNTPOFF: Name += "@INDNTPOFF"; break;
 211   case X86II::MO_TPOFF:     Name += "@TPOFF";     break;
 212   case X86II::MO_NTPOFF:    Name += "@NTPOFF";    break;
 213   case X86II::MO_GOTPCREL:  Name += "@GOTPCREL";  break;
 214   case X86II::MO_GOT:       Name += "@GOT";       break;
 215   case X86II::MO_GOTOFF:    Name += "@GOTOFF";    break;
 216   case X86II::MO_PLT:       Name += "@PLT";       break;
 217   }
 218
 219   // Create a symbol for the name.
 220   return Ctx.GetOrCreateSymbol(Name.str());
 221 }
 222
 223 MCOperand X86MCInstLower::LowerSymbolOperand(const MachineOperand &MO,
 224                                              MCSymbol *Sym) const {
 225   // FIXME: We would like an efficient form for this, so we don't have to do a
 226   // lot of extra uniquing.
 227   const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
 228
 229   switch (MO.getTargetFlags()) {
 230   default: llvm_unreachable("Unknown target flag on GV operand");
 231   case X86II::MO_NO_FLAG:    // No flag.
 232
 233   // These affect the name of the symbol, not any suffix.
 234   case X86II::MO_DARWIN_NONLAZY:
 235   case X86II::MO_DLLIMPORT:
 236   case X86II::MO_DARWIN_STUB:
 237   case X86II::MO_TLSGD:
 238   case X86II::MO_GOTTPOFF:
 239   case X86II::MO_INDNTPOFF:
 240   case X86II::MO_TPOFF:
 241   case X86II::MO_NTPOFF:
 242   case X86II::MO_GOTPCREL:
 243   case X86II::MO_GOT:
 244   case X86II::MO_GOTOFF:
 245   case X86II::MO_PLT:
 246     break;
 247   case X86II::MO_PIC_BASE_OFFSET:
 248   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
 249   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
 250     // Subtract the pic base.
 251     Expr = MCBinaryExpr::CreateSub(Expr,
 252                                MCSymbolRefExpr::Create(GetPICBaseSymbol(), Ctx),
 253                                    Ctx);
 254     break;
 255   }
 256
 257   if (!MO.isJTI() && MO.getOffset())
 258     Expr = MCBinaryExpr::CreateAdd(Expr,
 259                                    MCConstantExpr::Create(MO.getOffset(), Ctx),
 260                                    Ctx);
 261   return MCOperand::CreateExpr(Expr);
 262 }
 263
 264
 265
 266 static void lower_subreg32(MCInst *MI, unsigned OpNo) {
 267   // Convert registers in the addr mode according to subreg32.
 268   unsigned Reg = MI->getOperand(OpNo).getReg();
 269   if (Reg != 0)
 270     MI->getOperand(OpNo).setReg(getX86SubSuperRegister(Reg, MVT::i32));
 271 }
 272
 273 static void lower_lea64_32mem(MCInst *MI, unsigned OpNo) {
 274   // Convert registers in the addr mode according to subreg64.
 275   for (unsigned i = 0; i != 4; ++i) {
 276     if (!MI->getOperand(OpNo+i).isReg()) continue;
 277
 278     unsigned Reg = MI->getOperand(OpNo+i).getReg();
 279     if (Reg == 0) continue;
 280
 281     MI->getOperand(OpNo+i).setReg(getX86SubSuperRegister(Reg, MVT::i64));
 282   }
 283 }
 284
 285
 286
 287 void X86MCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
 288   OutMI.setOpcode(MI->getOpcode());
 289
 290   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
 291     const MachineOperand &MO = MI->getOperand(i);
 292
 293     MCOperand MCOp;
 294     switch (MO.getType()) {
 295     default:
 296       MI->dump();
 297       llvm_unreachable("unknown operand type");
 298     case MachineOperand::MO_Register:
 299       MCOp = MCOperand::CreateReg(MO.getReg());
 300       break;
 301     case MachineOperand::MO_Immediate:
 302       MCOp = MCOperand::CreateImm(MO.getImm());
 303       break;
 304     case MachineOperand::MO_MachineBasicBlock:
 305       MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
 306                        AsmPrinter.GetMBBSymbol(MO.getMBB()->getNumber()), Ctx));
 307       break;
 308     case MachineOperand::MO_GlobalAddress:
 309       MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
 310       break;
 311     case MachineOperand::MO_ExternalSymbol:
 312       MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
 313       break;
 314     case MachineOperand::MO_JumpTableIndex:
 315       MCOp = LowerSymbolOperand(MO, GetJumpTableSymbol(MO));
 316       break;
 317     case MachineOperand::MO_ConstantPoolIndex:
 318       MCOp = LowerSymbolOperand(MO, GetConstantPoolIndexSymbol(MO));
 319       break;
 320     }
 321
 322     OutMI.addOperand(MCOp);
 323   }
 324
 325   // Handle a few special cases to eliminate operand modifiers.
 326   switch (OutMI.getOpcode()) {
 327   case X86::LEA64_32r: // Handle 'subreg rewriting' for the lea64_32mem operand.
 328     lower_lea64_32mem(&OutMI, 1);
 329     break;
 330   case X86::MOV16r0:
 331     OutMI.setOpcode(X86::MOV32r0);
 332     lower_subreg32(&OutMI, 0);
 333     break;
 334   case X86::MOVZX16rr8:
 335     OutMI.setOpcode(X86::MOVZX32rr8);
 336     lower_subreg32(&OutMI, 0);
 337     break;
 338   case X86::MOVZX16rm8:
 339     OutMI.setOpcode(X86::MOVZX32rm8);
 340     lower_subreg32(&OutMI, 0);
 341     break;
 342   case X86::MOVSX16rr8:
 343     OutMI.setOpcode(X86::MOVSX32rr8);
 344     lower_subreg32(&OutMI, 0);
 345     break;
 346   case X86::MOVSX16rm8:
 347     OutMI.setOpcode(X86::MOVSX32rm8);
 348     lower_subreg32(&OutMI, 0);
 349     break;
 350   case X86::MOVZX64rr32:
 351     OutMI.setOpcode(X86::MOV32rr);
 352     lower_subreg32(&OutMI, 0);
 353     break;
 354   case X86::MOVZX64rm32:
 355     OutMI.setOpcode(X86::MOV32rm);
 356     lower_subreg32(&OutMI, 0);
 357     break;
 358   case X86::MOV64ri64i32:
 359     OutMI.setOpcode(X86::MOV32ri);
 360     lower_subreg32(&OutMI, 0);
 361     break;
 362   case X86::MOVZX64rr8:
 363     OutMI.setOpcode(X86::MOVZX32rr8);
 364     lower_subreg32(&OutMI, 0);
 365     break;
 366   case X86::MOVZX64rm8:
 367     OutMI.setOpcode(X86::MOVZX32rm8);
 368     lower_subreg32(&OutMI, 0);
 369     break;
 370   case X86::MOVZX64rr16:
 371     OutMI.setOpcode(X86::MOVZX32rr16);
 372     lower_subreg32(&OutMI, 0);
 373     break;
 374   case X86::MOVZX64rm16:
 375     OutMI.setOpcode(X86::MOVZX32rm16);
 376     lower_subreg32(&OutMI, 0);
 377     break;
 378   }
 379 }
 380
 381
 382
 383 void X86ATTAsmPrinter::
 384 printInstructionThroughMCStreamer(const MachineInstr *MI) {
 385   X86MCInstLower MCInstLowering(OutContext, Mang, *this);
 386   switch (MI->getOpcode()) {
 387   case TargetInstrInfo::DBG_LABEL:
 388   case TargetInstrInfo::EH_LABEL:
 389   case TargetInstrInfo::GC_LABEL:
 390     printLabel(MI);
 391     return;
 392   case TargetInstrInfo::INLINEASM:
 393     O << '\t';
 394     printInlineAsm(MI);
 395     return;
 396   case TargetInstrInfo::IMPLICIT_DEF:
 397     printImplicitDef(MI);
 398     return;
 399   case X86::MOVPC32r: {
 400     MCInst TmpInst;
 401     // This is a pseudo op for a two instruction sequence with a label, which
 402     // looks like:
 403     //     call "L1$pb"
 404     // "L1$pb":
 405     //     popl %esi
 406
 407     // Emit the call.
 408     MCSymbol *PICBase = MCInstLowering.GetPICBaseSymbol();
 409     TmpInst.setOpcode(X86::CALLpcrel32);
 410     // FIXME: We would like an efficient form for this, so we don't have to do a
 411     // lot of extra uniquing.
 412     TmpInst.addOperand(MCOperand::CreateExpr(MCSymbolRefExpr::Create(PICBase,
 413                                                                  OutContext)));
 414     printMCInst(&TmpInst);
 415     O << '\n';
 416
 417     // Emit the label.
 418     OutStreamer.EmitLabel(PICBase);
 419
 420     // popl $reg
 421     TmpInst.setOpcode(X86::POP32r);
 422     TmpInst.getOperand(0) = MCOperand::CreateReg(MI->getOperand(0).getReg());
 423     printMCInst(&TmpInst);
 424     return;
 425   }
 426
 427   case X86::ADD32ri: {
 428     // Lower the MO_GOT_ABSOLUTE_ADDRESS form of ADD32ri.
 429     if (MI->getOperand(2).getTargetFlags() != X86II::MO_GOT_ABSOLUTE_ADDRESS)
 430       break;
 431
 432     // Okay, we have something like:
 433     //  EAX = ADD32ri EAX, MO_GOT_ABSOLUTE_ADDRESS(@MYGLOBAL)
 434
 435     // For this, we want to print something like:
 436     //   MYGLOBAL + (. - PICBASE)
 437     // However, we can't generate a ".", so just emit a new label here and refer
 438     // to it.  We know that this operand flag occurs at most once per function.
 439     SmallString<64> Name;
 440     raw_svector_ostream(Name) << MAI->getPrivateGlobalPrefix()
 441       << "picbaseref" << getFunctionNumber();
 442     MCSymbol *DotSym = OutContext.GetOrCreateSymbol(Name.str());
 443     OutStreamer.EmitLabel(DotSym);
 444
 445     // Now that we have emitted the label, lower the complex operand expression.
 446     MCSymbol *OpSym = MCInstLowering.GetExternalSymbolSymbol(MI->getOperand(2));
 447
 448     const MCExpr *DotExpr = MCSymbolRefExpr::Create(DotSym, OutContext);
 449     const MCExpr *PICBase =
 450       MCSymbolRefExpr::Create(MCInstLowering.GetPICBaseSymbol(), OutContext);
 451     DotExpr = MCBinaryExpr::CreateSub(DotExpr, PICBase, OutContext);
 452
 453     DotExpr = MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(OpSym,OutContext),
 454                                       DotExpr, OutContext);
 455
 456     MCInst TmpInst;
 457     TmpInst.setOpcode(X86::ADD32ri);
 458     TmpInst.addOperand(MCOperand::CreateReg(MI->getOperand(0).getReg()));
 459     TmpInst.addOperand(MCOperand::CreateReg(MI->getOperand(1).getReg()));
 460     TmpInst.addOperand(MCOperand::CreateExpr(DotExpr));
 461     printMCInst(&TmpInst);
 462     return;
 463   }
 464   }
 465
 466   MCInst TmpInst;
 467   MCInstLowering.Lower(MI, TmpInst);
 468
 469
 470   printMCInst(&TmpInst);
 471 }
 472