SemaStmtAsm.cpp revision ae07378ff9bf4af9bdd97a4607437ace4c32b7e7 
1//===--- SemaStmtAsm.cpp - Semantic Analysis for Asm Statements -----------===//
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 implements semantic analysis for inline asm statements.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Sema/SemaInternal.h"
15#include "clang/AST/RecordLayout.h"
16#include "clang/AST/TypeLoc.h"
17#include "clang/Basic/TargetInfo.h"
18#include "clang/Lex/Preprocessor.h"
19#include "clang/Sema/Initialization.h"
20#include "clang/Sema/Lookup.h"
21#include "clang/Sema/Scope.h"
22#include "clang/Sema/ScopeInfo.h"
23#include "llvm/ADT/ArrayRef.h"
24#include "llvm/ADT/BitVector.h"
25#include "llvm/ADT/SmallString.h"
26#include "llvm/MC/MCAsmInfo.h"
27#include "llvm/MC/MCContext.h"
28#include "llvm/MC/MCObjectFileInfo.h"
29#include "llvm/MC/MCParser/MCAsmParser.h"
30#include "llvm/MC/MCRegisterInfo.h"
31#include "llvm/MC/MCStreamer.h"
32#include "llvm/MC/MCSubtargetInfo.h"
33#include "llvm/MC/MCTargetAsmParser.h"
34#include "llvm/Support/SourceMgr.h"
35#include "llvm/Support/TargetRegistry.h"
36#include "llvm/Support/TargetSelect.h"
37using namespace clang;
38using namespace sema;
39
40/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
41/// ignore "noop" casts in places where an lvalue is required by an inline asm.
42/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
43/// provide a strong guidance to not use it.
44///
45/// This method checks to see if the argument is an acceptable l-value and
46/// returns false if it is a case we can handle.
47static bool CheckAsmLValue(const Expr *E, Sema &S) {
48  // Type dependent expressions will be checked during instantiation.
49  if (E->isTypeDependent())
50    return false;
51
52  if (E->isLValue())
53    return false;  // Cool, this is an lvalue.
54
55  // Okay, this is not an lvalue, but perhaps it is the result of a cast that we
56  // are supposed to allow.
57  const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
58  if (E != E2 && E2->isLValue()) {
59    if (!S.getLangOpts().HeinousExtensions)
60      S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
61        << E->getSourceRange();
62    else
63      S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
64        << E->getSourceRange();
65    // Accept, even if we emitted an error diagnostic.
66    return false;
67  }
68
69  // None of the above, just randomly invalid non-lvalue.
70  return true;
71}
72
73/// isOperandMentioned - Return true if the specified operand # is mentioned
74/// anywhere in the decomposed asm string.
75static bool isOperandMentioned(unsigned OpNo,
76                         ArrayRef<GCCAsmStmt::AsmStringPiece> AsmStrPieces) {
77  for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) {
78    const GCCAsmStmt::AsmStringPiece &Piece = AsmStrPieces[p];
79    if (!Piece.isOperand()) continue;
80
81    // If this is a reference to the input and if the input was the smaller
82    // one, then we have to reject this asm.
83    if (Piece.getOperandNo() == OpNo)
84      return true;
85  }
86  return false;
87}
88
89StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
90                                 bool IsVolatile, unsigned NumOutputs,
91                                 unsigned NumInputs, IdentifierInfo **Names,
92                                 MultiExprArg constraints, MultiExprArg exprs,
93                                 Expr *asmString, MultiExprArg clobbers,
94                                 SourceLocation RParenLoc) {
95  unsigned NumClobbers = clobbers.size();
96  StringLiteral **Constraints =
97    reinterpret_cast<StringLiteral**>(constraints.data());
98  Expr **Exprs = exprs.data();
99  StringLiteral *AsmString = cast<StringLiteral>(asmString);
100  StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.data());
101
102  SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
103
104  // The parser verifies that there is a string literal here.
105  if (!AsmString->isAscii())
106    return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
107      << AsmString->getSourceRange());
108
109  for (unsigned i = 0; i != NumOutputs; i++) {
110    StringLiteral *Literal = Constraints[i];
111    if (!Literal->isAscii())
112      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
113        << Literal->getSourceRange());
114
115    StringRef OutputName;
116    if (Names[i])
117      OutputName = Names[i]->getName();
118
119    TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
120    if (!Context.getTargetInfo().validateOutputConstraint(Info))
121      return StmtError(Diag(Literal->getLocStart(),
122                            diag::err_asm_invalid_output_constraint)
123                       << Info.getConstraintStr());
124
125    // Check that the output exprs are valid lvalues.
126    Expr *OutputExpr = Exprs[i];
127    if (CheckAsmLValue(OutputExpr, *this)) {
128      return StmtError(Diag(OutputExpr->getLocStart(),
129                  diag::err_asm_invalid_lvalue_in_output)
130        << OutputExpr->getSourceRange());
131    }
132
133    OutputConstraintInfos.push_back(Info);
134  }
135
136  SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
137
138  for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
139    StringLiteral *Literal = Constraints[i];
140    if (!Literal->isAscii())
141      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
142        << Literal->getSourceRange());
143
144    StringRef InputName;
145    if (Names[i])
146      InputName = Names[i]->getName();
147
148    TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
149    if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(),
150                                                NumOutputs, Info)) {
151      return StmtError(Diag(Literal->getLocStart(),
152                            diag::err_asm_invalid_input_constraint)
153                       << Info.getConstraintStr());
154    }
155
156    Expr *InputExpr = Exprs[i];
157
158    // Only allow void types for memory constraints.
159    if (Info.allowsMemory() && !Info.allowsRegister()) {
160      if (CheckAsmLValue(InputExpr, *this))
161        return StmtError(Diag(InputExpr->getLocStart(),
162                              diag::err_asm_invalid_lvalue_in_input)
163                         << Info.getConstraintStr()
164                         << InputExpr->getSourceRange());
165    }
166
167    if (Info.allowsRegister()) {
168      if (InputExpr->getType()->isVoidType()) {
169        return StmtError(Diag(InputExpr->getLocStart(),
170                              diag::err_asm_invalid_type_in_input)
171          << InputExpr->getType() << Info.getConstraintStr()
172          << InputExpr->getSourceRange());
173      }
174    }
175
176    ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
177    if (Result.isInvalid())
178      return StmtError();
179
180    Exprs[i] = Result.take();
181    InputConstraintInfos.push_back(Info);
182
183    const Type *Ty = Exprs[i]->getType().getTypePtr();
184    if (Ty->isDependentType() || Ty->isIncompleteType())
185      continue;
186
187    unsigned Size = Context.getTypeSize(Ty);
188    if (!Context.getTargetInfo().validateInputSize(Literal->getString(),
189                                                   Size))
190      return StmtError(Diag(InputExpr->getLocStart(),
191                            diag::err_asm_invalid_input_size)
192                       << Info.getConstraintStr());
193  }
194
195  // Check that the clobbers are valid.
196  for (unsigned i = 0; i != NumClobbers; i++) {
197    StringLiteral *Literal = Clobbers[i];
198    if (!Literal->isAscii())
199      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
200        << Literal->getSourceRange());
201
202    StringRef Clobber = Literal->getString();
203
204    if (!Context.getTargetInfo().isValidClobber(Clobber))
205      return StmtError(Diag(Literal->getLocStart(),
206                  diag::err_asm_unknown_register_name) << Clobber);
207  }
208
209  GCCAsmStmt *NS =
210    new (Context) GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs,
211                             NumInputs, Names, Constraints, Exprs, AsmString,
212                             NumClobbers, Clobbers, RParenLoc);
213  // Validate the asm string, ensuring it makes sense given the operands we
214  // have.
215  SmallVector<GCCAsmStmt::AsmStringPiece, 8> Pieces;
216  unsigned DiagOffs;
217  if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
218    Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
219           << AsmString->getSourceRange();
220    return StmtError();
221  }
222
223  // Validate constraints and modifiers.
224  for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
225    GCCAsmStmt::AsmStringPiece &Piece = Pieces[i];
226    if (!Piece.isOperand()) continue;
227
228    // Look for the correct constraint index.
229    unsigned Idx = 0;
230    unsigned ConstraintIdx = 0;
231    for (unsigned i = 0, e = NS->getNumOutputs(); i != e; ++i, ++ConstraintIdx) {
232      TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
233      if (Idx == Piece.getOperandNo())
234        break;
235      ++Idx;
236
237      if (Info.isReadWrite()) {
238        if (Idx == Piece.getOperandNo())
239          break;
240        ++Idx;
241      }
242    }
243
244    for (unsigned i = 0, e = NS->getNumInputs(); i != e; ++i, ++ConstraintIdx) {
245      TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
246      if (Idx == Piece.getOperandNo())
247        break;
248      ++Idx;
249
250      if (Info.isReadWrite()) {
251        if (Idx == Piece.getOperandNo())
252          break;
253        ++Idx;
254      }
255    }
256
257    // Now that we have the right indexes go ahead and check.
258    StringLiteral *Literal = Constraints[ConstraintIdx];
259    const Type *Ty = Exprs[ConstraintIdx]->getType().getTypePtr();
260    if (Ty->isDependentType() || Ty->isIncompleteType())
261      continue;
262
263    unsigned Size = Context.getTypeSize(Ty);
264    if (!Context.getTargetInfo()
265          .validateConstraintModifier(Literal->getString(), Piece.getModifier(),
266                                      Size))
267      Diag(Exprs[ConstraintIdx]->getLocStart(),
268           diag::warn_asm_mismatched_size_modifier);
269  }
270
271  // Validate tied input operands for type mismatches.
272  for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
273    TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
274
275    // If this is a tied constraint, verify that the output and input have
276    // either exactly the same type, or that they are int/ptr operands with the
277    // same size (int/long, int*/long, are ok etc).
278    if (!Info.hasTiedOperand()) continue;
279
280    unsigned TiedTo = Info.getTiedOperand();
281    unsigned InputOpNo = i+NumOutputs;
282    Expr *OutputExpr = Exprs[TiedTo];
283    Expr *InputExpr = Exprs[InputOpNo];
284
285    if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent())
286      continue;
287
288    QualType InTy = InputExpr->getType();
289    QualType OutTy = OutputExpr->getType();
290    if (Context.hasSameType(InTy, OutTy))
291      continue;  // All types can be tied to themselves.
292
293    // Decide if the input and output are in the same domain (integer/ptr or
294    // floating point.
295    enum AsmDomain {
296      AD_Int, AD_FP, AD_Other
297    } InputDomain, OutputDomain;
298
299    if (InTy->isIntegerType() || InTy->isPointerType())
300      InputDomain = AD_Int;
301    else if (InTy->isRealFloatingType())
302      InputDomain = AD_FP;
303    else
304      InputDomain = AD_Other;
305
306    if (OutTy->isIntegerType() || OutTy->isPointerType())
307      OutputDomain = AD_Int;
308    else if (OutTy->isRealFloatingType())
309      OutputDomain = AD_FP;
310    else
311      OutputDomain = AD_Other;
312
313    // They are ok if they are the same size and in the same domain.  This
314    // allows tying things like:
315    //   void* to int*
316    //   void* to int            if they are the same size.
317    //   double to long double   if they are the same size.
318    //
319    uint64_t OutSize = Context.getTypeSize(OutTy);
320    uint64_t InSize = Context.getTypeSize(InTy);
321    if (OutSize == InSize && InputDomain == OutputDomain &&
322        InputDomain != AD_Other)
323      continue;
324
325    // If the smaller input/output operand is not mentioned in the asm string,
326    // then we can promote the smaller one to a larger input and the asm string
327    // won't notice.
328    bool SmallerValueMentioned = false;
329
330    // If this is a reference to the input and if the input was the smaller
331    // one, then we have to reject this asm.
332    if (isOperandMentioned(InputOpNo, Pieces)) {
333      // This is a use in the asm string of the smaller operand.  Since we
334      // codegen this by promoting to a wider value, the asm will get printed
335      // "wrong".
336      SmallerValueMentioned |= InSize < OutSize;
337    }
338    if (isOperandMentioned(TiedTo, Pieces)) {
339      // If this is a reference to the output, and if the output is the larger
340      // value, then it's ok because we'll promote the input to the larger type.
341      SmallerValueMentioned |= OutSize < InSize;
342    }
343
344    // If the smaller value wasn't mentioned in the asm string, and if the
345    // output was a register, just extend the shorter one to the size of the
346    // larger one.
347    if (!SmallerValueMentioned && InputDomain != AD_Other &&
348        OutputConstraintInfos[TiedTo].allowsRegister())
349      continue;
350
351    // Either both of the operands were mentioned or the smaller one was
352    // mentioned.  One more special case that we'll allow: if the tied input is
353    // integer, unmentioned, and is a constant, then we'll allow truncating it
354    // down to the size of the destination.
355    if (InputDomain == AD_Int && OutputDomain == AD_Int &&
356        !isOperandMentioned(InputOpNo, Pieces) &&
357        InputExpr->isEvaluatable(Context)) {
358      CastKind castKind =
359        (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast);
360      InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take();
361      Exprs[InputOpNo] = InputExpr;
362      NS->setInputExpr(i, InputExpr);
363      continue;
364    }
365
366    Diag(InputExpr->getLocStart(),
367         diag::err_asm_tying_incompatible_types)
368      << InTy << OutTy << OutputExpr->getSourceRange()
369      << InputExpr->getSourceRange();
370    return StmtError();
371  }
372
373  return Owned(NS);
374}
375
376// getSpelling - Get the spelling of the AsmTok token.
377static StringRef getSpelling(Sema &SemaRef, Token AsmTok) {
378  StringRef Asm;
379  SmallString<512> TokenBuf;
380  TokenBuf.resize(512);
381  bool StringInvalid = false;
382  Asm = SemaRef.PP.getSpelling(AsmTok, TokenBuf, &StringInvalid);
383  assert (!StringInvalid && "Expected valid string!");
384  return Asm;
385}
386
387// Build the inline assembly string.  Returns true on error.
388static bool buildMSAsmString(Sema &SemaRef,
389                             SourceLocation AsmLoc,
390                             ArrayRef<Token> AsmToks,
391                             SmallVectorImpl<unsigned> &TokOffsets,
392                             std::string &AsmString) {
393  assert (!AsmToks.empty() && "Didn't expect an empty AsmToks!");
394
395  SmallString<512> Asm;
396  for (unsigned i = 0, e = AsmToks.size(); i < e; ++i) {
397    bool isNewAsm = ((i == 0) ||
398                     AsmToks[i].isAtStartOfLine() ||
399                     AsmToks[i].is(tok::kw_asm));
400    if (isNewAsm) {
401      if (i != 0)
402        Asm += "\n\t";
403
404      if (AsmToks[i].is(tok::kw_asm)) {
405        i++; // Skip __asm
406        if (i == e) {
407          SemaRef.Diag(AsmLoc, diag::err_asm_empty);
408          return true;
409        }
410
411      }
412    }
413
414    if (i && AsmToks[i].hasLeadingSpace() && !isNewAsm)
415      Asm += ' ';
416
417    StringRef Spelling = getSpelling(SemaRef, AsmToks[i]);
418    Asm += Spelling;
419    TokOffsets.push_back(Asm.size());
420  }
421  AsmString = Asm.str();
422  return false;
423}
424
425namespace {
426
427class MCAsmParserSemaCallbackImpl : public llvm::MCAsmParserSemaCallback {
428  Sema &SemaRef;
429  SourceLocation AsmLoc;
430  ArrayRef<Token> AsmToks;
431  ArrayRef<unsigned> TokOffsets;
432
433public:
434  MCAsmParserSemaCallbackImpl(Sema &Ref, SourceLocation Loc,
435                              ArrayRef<Token> Toks,
436                              ArrayRef<unsigned> Offsets)
437    : SemaRef(Ref), AsmLoc(Loc), AsmToks(Toks), TokOffsets(Offsets) { }
438  ~MCAsmParserSemaCallbackImpl() {}
439
440  void *LookupInlineAsmIdentifier(StringRef Name, void *SrcLoc,
441                                  unsigned &Length, unsigned &Size,
442                                  unsigned &Type, bool &IsVarDecl){
443    SourceLocation Loc = SourceLocation::getFromPtrEncoding(SrcLoc);
444
445    NamedDecl *OpDecl = SemaRef.LookupInlineAsmIdentifier(Name, Loc, Length,
446                                                          Size, Type,
447                                                          IsVarDecl);
448    return static_cast<void *>(OpDecl);
449  }
450
451  bool LookupInlineAsmField(StringRef Base, StringRef Member,
452                            unsigned &Offset) {
453    return SemaRef.LookupInlineAsmField(Base, Member, Offset, AsmLoc);
454  }
455
456  static void MSAsmDiagHandlerCallback(const llvm::SMDiagnostic &D,
457                                       void *Context) {
458    ((MCAsmParserSemaCallbackImpl*)Context)->MSAsmDiagHandler(D);
459  }
460  void MSAsmDiagHandler(const llvm::SMDiagnostic &D) {
461    // Compute an offset into the inline asm buffer.
462    // FIXME: This isn't right if .macro is involved (but hopefully, no
463    // real-world code does that).
464    const llvm::SourceMgr &LSM = *D.getSourceMgr();
465    const llvm::MemoryBuffer *LBuf =
466    LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
467    unsigned Offset = D.getLoc().getPointer()  - LBuf->getBufferStart();
468
469    // Figure out which token that offset points into.
470    const unsigned *OffsetPtr =
471        std::lower_bound(TokOffsets.begin(), TokOffsets.end(), Offset);
472    unsigned TokIndex = OffsetPtr - TokOffsets.begin();
473
474    // If we come up with an answer which seems sane, use it; otherwise,
475    // just point at the __asm keyword.
476    // FIXME: Assert the answer is sane once we handle .macro correctly.
477    SourceLocation Loc = AsmLoc;
478    if (TokIndex < AsmToks.size()) {
479      const Token *Tok = &AsmToks[TokIndex];
480      Loc = Tok->getLocation();
481      Loc = Loc.getLocWithOffset(Offset - (*OffsetPtr - Tok->getLength()));
482    }
483    SemaRef.Diag(Loc, diag::err_inline_ms_asm_parsing) << D.getMessage();
484  }
485};
486
487}
488
489NamedDecl *Sema::LookupInlineAsmIdentifier(StringRef Name, SourceLocation Loc,
490                                           unsigned &Length, unsigned &Size,
491                                           unsigned &Type, bool &IsVarDecl) {
492  Length = 1;
493  Size = 0;
494  Type = 0;
495  IsVarDecl = false;
496  LookupResult Result(*this, &Context.Idents.get(Name), Loc,
497                      Sema::LookupOrdinaryName);
498
499  if (!LookupName(Result, getCurScope())) {
500    // If we don't find anything, return null; the AsmParser will assume
501    // it is a label of some sort.
502    return 0;
503  }
504
505  if (!Result.isSingleResult()) {
506    // FIXME: Diagnose result.
507    return 0;
508  }
509
510  NamedDecl *ND = Result.getFoundDecl();
511  if (isa<VarDecl>(ND) || isa<FunctionDecl>(ND)) {
512    if (VarDecl *Var = dyn_cast<VarDecl>(ND)) {
513      Type = Context.getTypeInfo(Var->getType()).first;
514      QualType Ty = Var->getType();
515      if (Ty->isArrayType()) {
516        const ArrayType *ATy = Context.getAsArrayType(Ty);
517        Length = Type / Context.getTypeInfo(ATy->getElementType()).first;
518        Type /= Length; // Type is in terms of a single element.
519      }
520      Type /= 8; // Type is in terms of bits, but we want bytes.
521      Size = Length * Type;
522      IsVarDecl = true;
523    }
524    return ND;
525  }
526
527  // FIXME: Handle other kinds of results? (FieldDecl, etc.)
528  // FIXME: Diagnose if we find something we can't handle, like a typedef.
529  return 0;
530}
531
532bool Sema::LookupInlineAsmField(StringRef Base, StringRef Member,
533                                unsigned &Offset, SourceLocation AsmLoc) {
534  Offset = 0;
535  LookupResult BaseResult(*this, &Context.Idents.get(Base), SourceLocation(),
536                          LookupOrdinaryName);
537
538  if (!LookupName(BaseResult, getCurScope()))
539    return true;
540
541  if (!BaseResult.isSingleResult())
542    return true;
543
544  NamedDecl *FoundDecl = BaseResult.getFoundDecl();
545  const RecordType *RT = 0;
546  if (VarDecl *VD = dyn_cast<VarDecl>(FoundDecl)) {
547    RT = VD->getType()->getAs<RecordType>();
548  } else if (TypedefDecl *TD = dyn_cast<TypedefDecl>(FoundDecl)) {
549    RT = TD->getUnderlyingType()->getAs<RecordType>();
550  }
551  if (!RT)
552    return true;
553
554  if (RequireCompleteType(AsmLoc, QualType(RT, 0), 0))
555    return true;
556
557  LookupResult FieldResult(*this, &Context.Idents.get(Member), SourceLocation(),
558                           LookupMemberName);
559
560  if (!LookupQualifiedName(FieldResult, RT->getDecl()))
561    return true;
562
563  // FIXME: Handle IndirectFieldDecl?
564  FieldDecl *FD = dyn_cast<FieldDecl>(FieldResult.getFoundDecl());
565  if (!FD)
566    return true;
567
568  const ASTRecordLayout &RL = Context.getASTRecordLayout(RT->getDecl());
569  unsigned i = FD->getFieldIndex();
570  CharUnits Result = Context.toCharUnitsFromBits(RL.getFieldOffset(i));
571  Offset = (unsigned)Result.getQuantity();
572
573  return false;
574}
575
576StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
577                                ArrayRef<Token> AsmToks,SourceLocation EndLoc) {
578  SmallVector<IdentifierInfo*, 4> Names;
579  SmallVector<StringRef, 4> ConstraintRefs;
580  SmallVector<Expr*, 4> Exprs;
581  SmallVector<StringRef, 4> ClobberRefs;
582
583  llvm::Triple TheTriple = Context.getTargetInfo().getTriple();
584  llvm::Triple::ArchType ArchTy = TheTriple.getArch();
585  bool UnsupportedArch = ArchTy != llvm::Triple::x86 &&
586    ArchTy != llvm::Triple::x86_64;
587  if (UnsupportedArch)
588    Diag(AsmLoc, diag::err_msasm_unsupported_arch) << TheTriple.getArchName();
589
590  // Empty asm statements don't need to instantiate the AsmParser, etc.
591  if (UnsupportedArch || AsmToks.empty()) {
592    StringRef EmptyAsmStr;
593    MSAsmStmt *NS =
594      new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, /*IsSimple*/ true,
595                              /*IsVolatile*/ true, AsmToks, /*NumOutputs*/ 0,
596                              /*NumInputs*/ 0, Names, ConstraintRefs, Exprs,
597                              EmptyAsmStr, ClobberRefs, EndLoc);
598    return Owned(NS);
599  }
600
601  std::string AsmString;
602  SmallVector<unsigned, 8> TokOffsets;
603  if (buildMSAsmString(*this, AsmLoc, AsmToks, TokOffsets, AsmString))
604    return StmtError();
605
606  // Get the target specific parser.
607  std::string Error;
608  const std::string &TT = TheTriple.getTriple();
609  const llvm::Target *TheTarget(llvm::TargetRegistry::lookupTarget(TT, Error));
610
611  OwningPtr<llvm::MCAsmInfo> MAI(TheTarget->createMCAsmInfo(TT));
612  OwningPtr<llvm::MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TT));
613  OwningPtr<llvm::MCObjectFileInfo> MOFI(new llvm::MCObjectFileInfo());
614  OwningPtr<llvm::MCSubtargetInfo>
615    STI(TheTarget->createMCSubtargetInfo(TT, "", ""));
616
617  llvm::SourceMgr SrcMgr;
618  llvm::MCContext Ctx(*MAI, *MRI, MOFI.get(), &SrcMgr);
619  llvm::MemoryBuffer *Buffer =
620    llvm::MemoryBuffer::getMemBuffer(AsmString, "<inline asm>");
621
622  // Tell SrcMgr about this buffer, which is what the parser will pick up.
623  SrcMgr.AddNewSourceBuffer(Buffer, llvm::SMLoc());
624
625  OwningPtr<llvm::MCStreamer> Str(createNullStreamer(Ctx));
626  OwningPtr<llvm::MCAsmParser>
627    Parser(createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
628  OwningPtr<llvm::MCTargetAsmParser>
629    TargetParser(TheTarget->createMCAsmParser(*STI, *Parser));
630
631  // Get the instruction descriptor.
632  const llvm::MCInstrInfo *MII = TheTarget->createMCInstrInfo();
633  llvm::MCInstPrinter *IP =
634    TheTarget->createMCInstPrinter(1, *MAI, *MII, *MRI, *STI);
635
636  // Change to the Intel dialect.
637  Parser->setAssemblerDialect(1);
638  Parser->setTargetParser(*TargetParser.get());
639  Parser->setParsingInlineAsm(true);
640  TargetParser->setParsingInlineAsm(true);
641
642  MCAsmParserSemaCallbackImpl MCAPSI(*this, AsmLoc, AsmToks, TokOffsets);
643  TargetParser->setSemaCallback(&MCAPSI);
644  SrcMgr.setDiagHandler(MCAsmParserSemaCallbackImpl::MSAsmDiagHandlerCallback,
645                        &MCAPSI);
646
647  unsigned NumOutputs;
648  unsigned NumInputs;
649  std::string AsmStringIR;
650  SmallVector<std::pair<void *, bool>, 4> OpDecls;
651  SmallVector<std::string, 4> Constraints;
652  SmallVector<std::string, 4> Clobbers;
653  if (Parser->ParseMSInlineAsm(AsmLoc.getPtrEncoding(), AsmStringIR,
654                               NumOutputs, NumInputs, OpDecls, Constraints,
655                               Clobbers, MII, IP, MCAPSI))
656    return StmtError();
657
658  // Build the vector of clobber StringRefs.
659  unsigned NumClobbers = Clobbers.size();
660  ClobberRefs.resize(NumClobbers);
661  for (unsigned i = 0; i != NumClobbers; ++i)
662    ClobberRefs[i] = StringRef(Clobbers[i]);
663
664  // Recast the void pointers and build the vector of constraint StringRefs.
665  unsigned NumExprs = NumOutputs + NumInputs;
666  Names.resize(NumExprs);
667  ConstraintRefs.resize(NumExprs);
668  Exprs.resize(NumExprs);
669  for (unsigned i = 0, e = NumExprs; i != e; ++i) {
670    NamedDecl *OpDecl = static_cast<NamedDecl *>(OpDecls[i].first);
671    if (!OpDecl)
672      return StmtError();
673
674    DeclarationNameInfo NameInfo(OpDecl->getDeclName(), AsmLoc);
675    ExprResult OpExpr = BuildDeclarationNameExpr(CXXScopeSpec(), NameInfo,
676                                                 OpDecl);
677    if (OpExpr.isInvalid())
678      return StmtError();
679
680    // Need address of variable.
681    if (OpDecls[i].second)
682      OpExpr = BuildUnaryOp(getCurScope(), AsmLoc, clang::UO_AddrOf,
683                            OpExpr.take());
684
685    Names[i] = OpDecl->getIdentifier();
686    ConstraintRefs[i] = StringRef(Constraints[i]);
687    Exprs[i] = OpExpr.take();
688  }
689
690  bool IsSimple = NumExprs > 0;
691  MSAsmStmt *NS =
692    new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple,
693                            /*IsVolatile*/ true, AsmToks, NumOutputs, NumInputs,
694                            Names, ConstraintRefs, Exprs, AsmStringIR,
695                            ClobberRefs, EndLoc);
696  return Owned(NS);
697}
698