lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp

   1 //===-- AsmPrinterInlineAsm.cpp - AsmPrinter Inline Asm Handling ----------===//
   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 implements the inline assembler pieces of the AsmPrinter class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/ADT/SmallString.h"
  14 #include "llvm/ADT/Twine.h"
  15 #include "llvm/CodeGen/AsmPrinter.h"
  16 #include "llvm/CodeGen/MachineBasicBlock.h"
  17 #include "llvm/CodeGen/MachineFunction.h"
  18 #include "llvm/CodeGen/MachineModuleInfo.h"
  19 #include "llvm/CodeGen/TargetInstrInfo.h"
  20 #include "llvm/CodeGen/TargetRegisterInfo.h"
  21 #include "llvm/IR/Constants.h"
  22 #include "llvm/IR/DataLayout.h"
  23 #include "llvm/IR/InlineAsm.h"
  24 #include "llvm/IR/LLVMContext.h"
  25 #include "llvm/IR/Module.h"
  26 #include "llvm/MC/MCAsmInfo.h"
  27 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
  28 #include "llvm/MC/MCStreamer.h"
  29 #include "llvm/MC/MCSubtargetInfo.h"
  30 #include "llvm/MC/MCSymbol.h"
  31 #include "llvm/Support/ErrorHandling.h"
  32 #include "llvm/Support/MemoryBuffer.h"
  33 #include "llvm/Support/SourceMgr.h"
  34 #include "llvm/Support/TargetRegistry.h"
  35 #include "llvm/Support/raw_ostream.h"
  36 #include "llvm/Target/TargetMachine.h"
  37 using namespace llvm;
  38
  39 #define DEBUG_TYPE "asm-printer"
  40
  41 /// srcMgrDiagHandler - This callback is invoked when the SourceMgr for an
  42 /// inline asm has an error in it.  diagInfo is a pointer to the SrcMgrDiagInfo
  43 /// struct above.
  44 static void srcMgrDiagHandler(const SMDiagnostic &Diag, void *diagInfo) {
  45   AsmPrinter::SrcMgrDiagInfo *DiagInfo =
  46       static_cast<AsmPrinter::SrcMgrDiagInfo *>(diagInfo);
  47   assert(DiagInfo && "Diagnostic context not passed down?");
  48
  49   // Look up a LocInfo for the buffer this diagnostic is coming from.
  50   unsigned BufNum = DiagInfo->SrcMgr.FindBufferContainingLoc(Diag.getLoc());
  51   const MDNode *LocInfo = nullptr;
  52   if (BufNum > 0 && BufNum <= DiagInfo->LocInfos.size())
  53     LocInfo = DiagInfo->LocInfos[BufNum-1];
  54
  55   // If the inline asm had metadata associated with it, pull out a location
  56   // cookie corresponding to which line the error occurred on.
  57   unsigned LocCookie = 0;
  58   if (LocInfo) {
  59     unsigned ErrorLine = Diag.getLineNo()-1;
  60     if (ErrorLine >= LocInfo->getNumOperands())
  61       ErrorLine = 0;
  62
  63     if (LocInfo->getNumOperands() != 0)
  64       if (const ConstantInt *CI =
  65               mdconst::dyn_extract<ConstantInt>(LocInfo->getOperand(ErrorLine)))
  66         LocCookie = CI->getZExtValue();
  67   }
  68
  69   DiagInfo->DiagHandler(Diag, DiagInfo->DiagContext, LocCookie);
  70 }
  71
  72 unsigned AsmPrinter::addInlineAsmDiagBuffer(StringRef AsmStr,
  73                                             const MDNode *LocMDNode) const {
  74   if (!DiagInfo) {
  75     DiagInfo = make_unique<SrcMgrDiagInfo>();
  76
  77     MCContext &Context = MMI->getContext();
  78     Context.setInlineSourceManager(&DiagInfo->SrcMgr);
  79
  80     LLVMContext &LLVMCtx = MMI->getModule()->getContext();
  81     if (LLVMCtx.getInlineAsmDiagnosticHandler()) {
  82       DiagInfo->DiagHandler = LLVMCtx.getInlineAsmDiagnosticHandler();
  83       DiagInfo->DiagContext = LLVMCtx.getInlineAsmDiagnosticContext();
  84       DiagInfo->SrcMgr.setDiagHandler(srcMgrDiagHandler, DiagInfo.get());
  85     }
  86   }
  87
  88   SourceMgr &SrcMgr = DiagInfo->SrcMgr;
  89
  90   std::unique_ptr<MemoryBuffer> Buffer;
  91   // The inline asm source manager will outlive AsmStr, so make a copy of the
  92   // string for SourceMgr to own.
  93   Buffer = MemoryBuffer::getMemBufferCopy(AsmStr, "<inline asm>");
  94
  95   // Tell SrcMgr about this buffer, it takes ownership of the buffer.
  96   unsigned BufNum = SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
  97
  98   // Store LocMDNode in DiagInfo, using BufNum as an identifier.
  99   if (LocMDNode) {
 100     DiagInfo->LocInfos.resize(BufNum);
 101     DiagInfo->LocInfos[BufNum - 1] = LocMDNode;
 102   }
 103
 104   return BufNum;
 105 }
 106
 107
 108 /// EmitInlineAsm - Emit a blob of inline asm to the output streamer.
 109 void AsmPrinter::EmitInlineAsm(StringRef Str, const MCSubtargetInfo &STI,
 110                                const MCTargetOptions &MCOptions,
 111                                const MDNode *LocMDNode,
 112                                InlineAsm::AsmDialect Dialect) const {
 113   assert(!Str.empty() && "Can't emit empty inline asm block");
 114
 115   // Remember if the buffer is nul terminated or not so we can avoid a copy.
 116   bool isNullTerminated = Str.back() == 0;
 117   if (isNullTerminated)
 118     Str = Str.substr(0, Str.size()-1);
 119
 120   // If the output streamer does not have mature MC support or the integrated
 121   // assembler has been disabled, just emit the blob textually.
 122   // Otherwise parse the asm and emit it via MC support.
 123   // This is useful in case the asm parser doesn't handle something but the
 124   // system assembler does.
 125   const MCAsmInfo *MCAI = TM.getMCAsmInfo();
 126   assert(MCAI && "No MCAsmInfo");
 127   if (!MCAI->useIntegratedAssembler() &&
 128       !OutStreamer->isIntegratedAssemblerRequired()) {
 129     emitInlineAsmStart();
 130     OutStreamer->EmitRawText(Str);
 131     emitInlineAsmEnd(STI, nullptr);
 132     return;
 133   }
 134
 135   unsigned BufNum = addInlineAsmDiagBuffer(Str, LocMDNode);
 136   DiagInfo->SrcMgr.setIncludeDirs(MCOptions.IASSearchPaths);
 137
 138   std::unique_ptr<MCAsmParser> Parser(createMCAsmParser(
 139           DiagInfo->SrcMgr, OutContext, *OutStreamer, *MAI, BufNum));
 140
 141   // Do not use assembler-level information for parsing inline assembly.
 142   OutStreamer->setUseAssemblerInfoForParsing(false);
 143
 144   // We create a new MCInstrInfo here since we might be at the module level
 145   // and not have a MachineFunction to initialize the TargetInstrInfo from and
 146   // we only need MCInstrInfo for asm parsing. We create one unconditionally
 147   // because it's not subtarget dependent.
 148   std::unique_ptr<MCInstrInfo> MII(TM.getTarget().createMCInstrInfo());
 149   std::unique_ptr<MCTargetAsmParser> TAP(TM.getTarget().createMCAsmParser(
 150       STI, *Parser, *MII, MCOptions));
 151   if (!TAP)
 152     report_fatal_error("Inline asm not supported by this streamer because"
 153                        " we don't have an asm parser for this target\n");
 154   Parser->setAssemblerDialect(Dialect);
 155   Parser->setTargetParser(*TAP.get());
 156   // Enable lexing Masm binary and hex integer literals in intel inline
 157   // assembly.
 158   if (Dialect == InlineAsm::AD_Intel)
 159     Parser->getLexer().setLexMasmIntegers(true);
 160   if (MF) {
 161     const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
 162     TAP->SetFrameRegister(TRI->getFrameRegister(*MF));
 163   }
 164
 165   emitInlineAsmStart();
 166   // Don't implicitly switch to the text section before the asm.
 167   int Res = Parser->Run(/*NoInitialTextSection*/ true,
 168                         /*NoFinalize*/ true);
 169   emitInlineAsmEnd(STI, &TAP->getSTI());
 170
 171   if (Res && !DiagInfo->DiagHandler)
 172     report_fatal_error("Error parsing inline asm\n");
 173 }
 174
 175 static void EmitMSInlineAsmStr(const char *AsmStr, const MachineInstr *MI,
 176                                MachineModuleInfo *MMI, int InlineAsmVariant,
 177                                AsmPrinter *AP, unsigned LocCookie,
 178                                raw_ostream &OS) {
 179   // Switch to the inline assembly variant.
 180   OS << "\t.intel_syntax\n\t";
 181
 182   const char *LastEmitted = AsmStr; // One past the last character emitted.
 183   unsigned NumOperands = MI->getNumOperands();
 184
 185   while (*LastEmitted) {
 186     switch (*LastEmitted) {
 187     default: {
 188       // Not a special case, emit the string section literally.
 189       const char *LiteralEnd = LastEmitted+1;
 190       while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
 191              *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
 192         ++LiteralEnd;
 193
 194       OS.write(LastEmitted, LiteralEnd-LastEmitted);
 195       LastEmitted = LiteralEnd;
 196       break;
 197     }
 198     case '\n':
 199       ++LastEmitted;   // Consume newline character.
 200       OS << '\n';      // Indent code with newline.
 201       break;
 202     case '$': {
 203       ++LastEmitted;   // Consume '$' character.
 204       bool Done = true;
 205
 206       // Handle escapes.
 207       switch (*LastEmitted) {
 208       default: Done = false; break;
 209       case '$':
 210         ++LastEmitted;  // Consume second '$' character.
 211         break;
 212       }
 213       if (Done) break;
 214
 215       // If we have ${:foo}, then this is not a real operand reference, it is a
 216       // "magic" string reference, just like in .td files.  Arrange to call
 217       // PrintSpecial.
 218       if (LastEmitted[0] == '{' && LastEmitted[1] == ':') {
 219         LastEmitted += 2;
 220         const char *StrStart = LastEmitted;
 221         const char *StrEnd = strchr(StrStart, '}');
 222         if (!StrEnd)
 223           report_fatal_error("Unterminated ${:foo} operand in inline asm"
 224                              " string: '" + Twine(AsmStr) + "'");
 225
 226         std::string Val(StrStart, StrEnd);
 227         AP->PrintSpecial(MI, OS, Val.c_str());
 228         LastEmitted = StrEnd+1;
 229         break;
 230       }
 231
 232       const char *IDStart = LastEmitted;
 233       const char *IDEnd = IDStart;
 234       while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd;
 235
 236       unsigned Val;
 237       if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val))
 238         report_fatal_error("Bad $ operand number in inline asm string: '" +
 239                            Twine(AsmStr) + "'");
 240       LastEmitted = IDEnd;
 241
 242       if (Val >= NumOperands-1)
 243         report_fatal_error("Invalid $ operand number in inline asm string: '" +
 244                            Twine(AsmStr) + "'");
 245
 246       // Okay, we finally have a value number.  Ask the target to print this
 247       // operand!
 248       unsigned OpNo = InlineAsm::MIOp_FirstOperand;
 249
 250       bool Error = false;
 251
 252       // Scan to find the machine operand number for the operand.
 253       for (; Val; --Val) {
 254         if (OpNo >= MI->getNumOperands()) break;
 255         unsigned OpFlags = MI->getOperand(OpNo).getImm();
 256         OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
 257       }
 258
 259       // We may have a location metadata attached to the end of the
 260       // instruction, and at no point should see metadata at any
 261       // other point while processing. It's an error if so.
 262       if (OpNo >= MI->getNumOperands() ||
 263           MI->getOperand(OpNo).isMetadata()) {
 264         Error = true;
 265       } else {
 266         unsigned OpFlags = MI->getOperand(OpNo).getImm();
 267         ++OpNo;  // Skip over the ID number.
 268
 269         if (InlineAsm::isMemKind(OpFlags)) {
 270           Error = AP->PrintAsmMemoryOperand(MI, OpNo, InlineAsmVariant,
 271                                             /*Modifier*/ nullptr, OS);
 272         } else {
 273           Error = AP->PrintAsmOperand(MI, OpNo, InlineAsmVariant,
 274                                       /*Modifier*/ nullptr, OS);
 275         }
 276       }
 277       if (Error) {
 278         std::string msg;
 279         raw_string_ostream Msg(msg);
 280         Msg << "invalid operand in inline asm: '" << AsmStr << "'";
 281         MMI->getModule()->getContext().emitError(LocCookie, Msg.str());
 282       }
 283       break;
 284     }
 285     }
 286   }
 287   OS << "\n\t.att_syntax\n" << (char)0;  // null terminate string.
 288 }
 289
 290 static void EmitGCCInlineAsmStr(const char *AsmStr, const MachineInstr *MI,
 291                                 MachineModuleInfo *MMI, int InlineAsmVariant,
 292                                 int AsmPrinterVariant, AsmPrinter *AP,
 293                                 unsigned LocCookie, raw_ostream &OS) {
 294   int CurVariant = -1;            // The number of the {.|.|.} region we are in.
 295   const char *LastEmitted = AsmStr; // One past the last character emitted.
 296   unsigned NumOperands = MI->getNumOperands();
 297
 298   OS << '\t';
 299
 300   while (*LastEmitted) {
 301     switch (*LastEmitted) {
 302     default: {
 303       // Not a special case, emit the string section literally.
 304       const char *LiteralEnd = LastEmitted+1;
 305       while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
 306              *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
 307         ++LiteralEnd;
 308       if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
 309         OS.write(LastEmitted, LiteralEnd-LastEmitted);
 310       LastEmitted = LiteralEnd;
 311       break;
 312     }
 313     case '\n':
 314       ++LastEmitted;   // Consume newline character.
 315       OS << '\n';      // Indent code with newline.
 316       break;
 317     case '$': {
 318       ++LastEmitted;   // Consume '$' character.
 319       bool Done = true;
 320
 321       // Handle escapes.
 322       switch (*LastEmitted) {
 323       default: Done = false; break;
 324       case '$':     // $$ -> $
 325         if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
 326           OS << '$';
 327         ++LastEmitted;  // Consume second '$' character.
 328         break;
 329       case '(':             // $( -> same as GCC's { character.
 330         ++LastEmitted;      // Consume '(' character.
 331         if (CurVariant != -1)
 332           report_fatal_error("Nested variants found in inline asm string: '" +
 333                              Twine(AsmStr) + "'");
 334         CurVariant = 0;     // We're in the first variant now.
 335         break;
 336       case '|':
 337         ++LastEmitted;  // consume '|' character.
 338         if (CurVariant == -1)
 339           OS << '|';       // this is gcc's behavior for | outside a variant
 340         else
 341           ++CurVariant;   // We're in the next variant.
 342         break;
 343       case ')':         // $) -> same as GCC's } char.
 344         ++LastEmitted;  // consume ')' character.
 345         if (CurVariant == -1)
 346           OS << '}';     // this is gcc's behavior for } outside a variant
 347         else
 348           CurVariant = -1;
 349         break;
 350       }
 351       if (Done) break;
 352
 353       bool HasCurlyBraces = false;
 354       if (*LastEmitted == '{') {     // ${variable}
 355         ++LastEmitted;               // Consume '{' character.
 356         HasCurlyBraces = true;
 357       }
 358
 359       // If we have ${:foo}, then this is not a real operand reference, it is a
 360       // "magic" string reference, just like in .td files.  Arrange to call
 361       // PrintSpecial.
 362       if (HasCurlyBraces && *LastEmitted == ':') {
 363         ++LastEmitted;
 364         const char *StrStart = LastEmitted;
 365         const char *StrEnd = strchr(StrStart, '}');
 366         if (!StrEnd)
 367           report_fatal_error("Unterminated ${:foo} operand in inline asm"
 368                              " string: '" + Twine(AsmStr) + "'");
 369
 370         std::string Val(StrStart, StrEnd);
 371         AP->PrintSpecial(MI, OS, Val.c_str());
 372         LastEmitted = StrEnd+1;
 373         break;
 374       }
 375
 376       const char *IDStart = LastEmitted;
 377       const char *IDEnd = IDStart;
 378       while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd;
 379
 380       unsigned Val;
 381       if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val))
 382         report_fatal_error("Bad $ operand number in inline asm string: '" +
 383                            Twine(AsmStr) + "'");
 384       LastEmitted = IDEnd;
 385
 386       char Modifier[2] = { 0, 0 };
 387
 388       if (HasCurlyBraces) {
 389         // If we have curly braces, check for a modifier character.  This
 390         // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
 391         if (*LastEmitted == ':') {
 392           ++LastEmitted;    // Consume ':' character.
 393           if (*LastEmitted == 0)
 394             report_fatal_error("Bad ${:} expression in inline asm string: '" +
 395                                Twine(AsmStr) + "'");
 396
 397           Modifier[0] = *LastEmitted;
 398           ++LastEmitted;    // Consume modifier character.
 399         }
 400
 401         if (*LastEmitted != '}')
 402           report_fatal_error("Bad ${} expression in inline asm string: '" +
 403                              Twine(AsmStr) + "'");
 404         ++LastEmitted;    // Consume '}' character.
 405       }
 406
 407       if (Val >= NumOperands-1)
 408         report_fatal_error("Invalid $ operand number in inline asm string: '" +
 409                            Twine(AsmStr) + "'");
 410
 411       // Okay, we finally have a value number.  Ask the target to print this
 412       // operand!
 413       if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
 414         unsigned OpNo = InlineAsm::MIOp_FirstOperand;
 415
 416         bool Error = false;
 417
 418         // Scan to find the machine operand number for the operand.
 419         for (; Val; --Val) {
 420           if (OpNo >= MI->getNumOperands()) break;
 421           unsigned OpFlags = MI->getOperand(OpNo).getImm();
 422           OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
 423         }
 424
 425         // We may have a location metadata attached to the end of the
 426         // instruction, and at no point should see metadata at any
 427         // other point while processing. It's an error if so.
 428         if (OpNo >= MI->getNumOperands() ||
 429             MI->getOperand(OpNo).isMetadata()) {
 430           Error = true;
 431         } else {
 432           unsigned OpFlags = MI->getOperand(OpNo).getImm();
 433           ++OpNo;  // Skip over the ID number.
 434
 435           if (Modifier[0] == 'l') { // Labels are target independent.
 436             if (MI->getOperand(OpNo).isBlockAddress()) {
 437               const BlockAddress *BA = MI->getOperand(OpNo).getBlockAddress();
 438               MCSymbol *Sym = AP->GetBlockAddressSymbol(BA);
 439               Sym->print(OS, AP->MAI);
 440             } else if (MI->getOperand(OpNo).isMBB()) {
 441               const MCSymbol *Sym = MI->getOperand(OpNo).getMBB()->getSymbol();
 442               Sym->print(OS, AP->MAI);
 443             } else {
 444               Error = true;
 445             }
 446           } else {
 447             if (InlineAsm::isMemKind(OpFlags)) {
 448               Error = AP->PrintAsmMemoryOperand(MI, OpNo, InlineAsmVariant,
 449                                                 Modifier[0] ? Modifier : nullptr,
 450                                                 OS);
 451             } else {
 452               Error = AP->PrintAsmOperand(MI, OpNo, InlineAsmVariant,
 453                                           Modifier[0] ? Modifier : nullptr, OS);
 454             }
 455           }
 456         }
 457         if (Error) {
 458           std::string msg;
 459           raw_string_ostream Msg(msg);
 460           Msg << "invalid operand in inline asm: '" << AsmStr << "'";
 461           MMI->getModule()->getContext().emitError(LocCookie, Msg.str());
 462         }
 463       }
 464       break;
 465     }
 466     }
 467   }
 468   OS << '\n' << (char)0;  // null terminate string.
 469 }
 470
 471 /// EmitInlineAsm - This method formats and emits the specified machine
 472 /// instruction that is an inline asm.
 473 void AsmPrinter::EmitInlineAsm(const MachineInstr *MI) const {
 474   assert(MI->isInlineAsm() && "printInlineAsm only works on inline asms");
 475
 476   // Count the number of register definitions to find the asm string.
 477   unsigned NumDefs = 0;
 478   for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
 479        ++NumDefs)
 480     assert(NumDefs != MI->getNumOperands()-2 && "No asm string?");
 481
 482   assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");
 483
 484   // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
 485   const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
 486
 487   // If this asmstr is empty, just print the #APP/#NOAPP markers.
 488   // These are useful to see where empty asm's wound up.
 489   if (AsmStr[0] == 0) {
 490     OutStreamer->emitRawComment(MAI->getInlineAsmStart());
 491     OutStreamer->emitRawComment(MAI->getInlineAsmEnd());
 492     return;
 493   }
 494
 495   // Emit the #APP start marker.  This has to happen even if verbose-asm isn't
 496   // enabled, so we use emitRawComment.
 497   OutStreamer->emitRawComment(MAI->getInlineAsmStart());
 498
 499   // Get the !srcloc metadata node if we have it, and decode the loc cookie from
 500   // it.
 501   unsigned LocCookie = 0;
 502   const MDNode *LocMD = nullptr;
 503   for (unsigned i = MI->getNumOperands(); i != 0; --i) {
 504     if (MI->getOperand(i-1).isMetadata() &&
 505         (LocMD = MI->getOperand(i-1).getMetadata()) &&
 506         LocMD->getNumOperands() != 0) {
 507       if (const ConstantInt *CI =
 508               mdconst::dyn_extract<ConstantInt>(LocMD->getOperand(0))) {
 509         LocCookie = CI->getZExtValue();
 510         break;
 511       }
 512     }
 513   }
 514
 515   // Emit the inline asm to a temporary string so we can emit it through
 516   // EmitInlineAsm.
 517   SmallString<256> StringData;
 518   raw_svector_ostream OS(StringData);
 519
 520   // The variant of the current asmprinter.
 521   int AsmPrinterVariant = MAI->getAssemblerDialect();
 522   InlineAsm::AsmDialect InlineAsmVariant = MI->getInlineAsmDialect();
 523   AsmPrinter *AP = const_cast<AsmPrinter*>(this);
 524   if (InlineAsmVariant == InlineAsm::AD_ATT)
 525     EmitGCCInlineAsmStr(AsmStr, MI, MMI, InlineAsmVariant, AsmPrinterVariant,
 526                         AP, LocCookie, OS);
 527   else
 528     EmitMSInlineAsmStr(AsmStr, MI, MMI, InlineAsmVariant, AP, LocCookie, OS);
 529
 530   // Reset SanitizeAddress based on the function's attribute.
 531   MCTargetOptions MCOptions = TM.Options.MCOptions;
 532   MCOptions.SanitizeAddress =
 533       MF->getFunction().hasFnAttribute(Attribute::SanitizeAddress);
 534
 535   // Emit warnings if we use reserved registers on the clobber list, as
 536   // that might give surprising results.
 537   std::vector<std::string> RestrRegs;
 538   // Start with the first operand descriptor, and iterate over them.
 539   for (unsigned I = InlineAsm::MIOp_FirstOperand, NumOps = MI->getNumOperands();
 540        I < NumOps; ++I) {
 541     const MachineOperand &MO = MI->getOperand(I);
 542     if (MO.isImm()) {
 543       unsigned Flags = MO.getImm();
 544       const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
 545       if (InlineAsm::getKind(Flags) == InlineAsm::Kind_Clobber &&
 546           !TRI->isAsmClobberable(*MF, MI->getOperand(I + 1).getReg())) {
 547         RestrRegs.push_back(TRI->getName(MI->getOperand(I + 1).getReg()));
 548       }
 549       // Skip to one before the next operand descriptor, if it exists.
 550       I += InlineAsm::getNumOperandRegisters(Flags);
 551     }
 552   }
 553
 554   if (!RestrRegs.empty()) {
 555     unsigned BufNum = addInlineAsmDiagBuffer(OS.str(), LocMD);
 556     auto &SrcMgr = DiagInfo->SrcMgr;
 557     SMLoc Loc = SMLoc::getFromPointer(
 558         SrcMgr.getMemoryBuffer(BufNum)->getBuffer().begin());
 559
 560     std::string Msg = "inline asm clobber list contains reserved registers: ";
 561     for (auto I = RestrRegs.begin(), E = RestrRegs.end(); I != E; I++) {
 562       if(I != RestrRegs.begin())
 563         Msg += ", ";
 564       Msg += *I;
 565     }
 566     std::string Note = "Reserved registers on the clobber list may not be "
 567                 "preserved across the asm statement, and clobbering them may "
 568                 "lead to undefined behaviour.";
 569     SrcMgr.PrintMessage(Loc, SourceMgr::DK_Warning, Msg);
 570     SrcMgr.PrintMessage(Loc, SourceMgr::DK_Note, Note);
 571   }
 572
 573   EmitInlineAsm(OS.str(), getSubtargetInfo(), MCOptions, LocMD,
 574                 MI->getInlineAsmDialect());
 575
 576   // Emit the #NOAPP end marker.  This has to happen even if verbose-asm isn't
 577   // enabled, so we use emitRawComment.
 578   OutStreamer->emitRawComment(MAI->getInlineAsmEnd());
 579 }
 580
 581
 582 /// PrintSpecial - Print information related to the specified machine instr
 583 /// that is independent of the operand, and may be independent of the instr
 584 /// itself.  This can be useful for portably encoding the comment character
 585 /// or other bits of target-specific knowledge into the asmstrings.  The
 586 /// syntax used is ${:comment}.  Targets can override this to add support
 587 /// for their own strange codes.
 588 void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS,
 589                               const char *Code) const {
 590   if (!strcmp(Code, "private")) {
 591     const DataLayout &DL = MF->getDataLayout();
 592     OS << DL.getPrivateGlobalPrefix();
 593   } else if (!strcmp(Code, "comment")) {
 594     OS << MAI->getCommentString();
 595   } else if (!strcmp(Code, "uid")) {
 596     // Comparing the address of MI isn't sufficient, because machineinstrs may
 597     // be allocated to the same address across functions.
 598
 599     // If this is a new LastFn instruction, bump the counter.
 600     if (LastMI != MI || LastFn != getFunctionNumber()) {
 601       ++Counter;
 602       LastMI = MI;
 603       LastFn = getFunctionNumber();
 604     }
 605     OS << Counter;
 606   } else {
 607     std::string msg;
 608     raw_string_ostream Msg(msg);
 609     Msg << "Unknown special formatter '" << Code
 610          << "' for machine instr: " << *MI;
 611     report_fatal_error(Msg.str());
 612   }
 613 }
 614
 615 /// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
 616 /// instruction, using the specified assembler variant.  Targets should
 617 /// override this to format as appropriate.
 618 bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
 619                                  unsigned AsmVariant, const char *ExtraCode,
 620                                  raw_ostream &O) {
 621   // Does this asm operand have a single letter operand modifier?
 622   if (ExtraCode && ExtraCode[0]) {
 623     if (ExtraCode[1] != 0) return true; // Unknown modifier.
 624
 625     const MachineOperand &MO = MI->getOperand(OpNo);
 626     switch (ExtraCode[0]) {
 627     default:
 628       return true;  // Unknown modifier.
 629     case 'c': // Substitute immediate value without immediate syntax
 630       if (MO.getType() != MachineOperand::MO_Immediate)
 631         return true;
 632       O << MO.getImm();
 633       return false;
 634     case 'n':  // Negate the immediate constant.
 635       if (MO.getType() != MachineOperand::MO_Immediate)
 636         return true;
 637       O << -MO.getImm();
 638       return false;
 639     case 's':  // The GCC deprecated s modifier
 640       if (MO.getType() != MachineOperand::MO_Immediate)
 641         return true;
 642       O << ((32 - MO.getImm()) & 31);
 643       return false;
 644     }
 645   }
 646   return true;
 647 }
 648
 649 bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
 650                                        unsigned AsmVariant,
 651                                        const char *ExtraCode, raw_ostream &O) {
 652   // Target doesn't support this yet!
 653   return true;
 654 }
 655
 656 void AsmPrinter::emitInlineAsmStart() const {}
 657
 658 void AsmPrinter::emitInlineAsmEnd(const MCSubtargetInfo &StartInfo,
 659                                   const MCSubtargetInfo *EndInfo) const {}