SemaStmtAsm.cpp revision d835d9496c55848981c1d9db383a0de1be160925 
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    if (RequireCompleteType(OutputExpr->getLocStart(), Exprs[i]->getType(),
133                            diag::err_dereference_incomplete_type))
134      return StmtError();
135
136    OutputConstraintInfos.push_back(Info);
137  }
138
139  SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
140
141  for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
142    StringLiteral *Literal = Constraints[i];
143    if (!Literal->isAscii())
144      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
145        << Literal->getSourceRange());
146
147    StringRef InputName;
148    if (Names[i])
149      InputName = Names[i]->getName();
150
151    TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
152    if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(),
153                                                NumOutputs, Info)) {
154      return StmtError(Diag(Literal->getLocStart(),
155                            diag::err_asm_invalid_input_constraint)
156                       << Info.getConstraintStr());
157    }
158
159    Expr *InputExpr = Exprs[i];
160
161    // Only allow void types for memory constraints.
162    if (Info.allowsMemory() && !Info.allowsRegister()) {
163      if (CheckAsmLValue(InputExpr, *this))
164        return StmtError(Diag(InputExpr->getLocStart(),
165                              diag::err_asm_invalid_lvalue_in_input)
166                         << Info.getConstraintStr()
167                         << InputExpr->getSourceRange());
168    }
169
170    if (Info.allowsRegister()) {
171      if (InputExpr->getType()->isVoidType()) {
172        return StmtError(Diag(InputExpr->getLocStart(),
173                              diag::err_asm_invalid_type_in_input)
174          << InputExpr->getType() << Info.getConstraintStr()
175          << InputExpr->getSourceRange());
176      }
177    }
178
179    ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
180    if (Result.isInvalid())
181      return StmtError();
182
183    Exprs[i] = Result.take();
184    InputConstraintInfos.push_back(Info);
185
186    const Type *Ty = Exprs[i]->getType().getTypePtr();
187    if (Ty->isDependentType())
188      continue;
189
190    if (!Ty->isVoidType() || !Info.allowsMemory())
191      if (RequireCompleteType(InputExpr->getLocStart(), Exprs[i]->getType(),
192                              diag::err_dereference_incomplete_type))
193        return StmtError();
194
195    unsigned Size = Context.getTypeSize(Ty);
196    if (!Context.getTargetInfo().validateInputSize(Literal->getString(),
197                                                   Size))
198      return StmtError(Diag(InputExpr->getLocStart(),
199                            diag::err_asm_invalid_input_size)
200                       << Info.getConstraintStr());
201  }
202
203  // Check that the clobbers are valid.
204  for (unsigned i = 0; i != NumClobbers; i++) {
205    StringLiteral *Literal = Clobbers[i];
206    if (!Literal->isAscii())
207      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
208        << Literal->getSourceRange());
209
210    StringRef Clobber = Literal->getString();
211
212    if (!Context.getTargetInfo().isValidClobber(Clobber))
213      return StmtError(Diag(Literal->getLocStart(),
214                  diag::err_asm_unknown_register_name) << Clobber);
215  }
216
217  GCCAsmStmt *NS =
218    new (Context) GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs,
219                             NumInputs, Names, Constraints, Exprs, AsmString,
220                             NumClobbers, Clobbers, RParenLoc);
221  // Validate the asm string, ensuring it makes sense given the operands we
222  // have.
223  SmallVector<GCCAsmStmt::AsmStringPiece, 8> Pieces;
224  unsigned DiagOffs;
225  if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
226    Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
227           << AsmString->getSourceRange();
228    return StmtError();
229  }
230
231  // Validate constraints and modifiers.
232  for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
233    GCCAsmStmt::AsmStringPiece &Piece = Pieces[i];
234    if (!Piece.isOperand()) continue;
235
236    // Look for the correct constraint index.
237    unsigned Idx = 0;
238    unsigned ConstraintIdx = 0;
239    for (unsigned i = 0, e = NS->getNumOutputs(); i != e; ++i, ++ConstraintIdx) {
240      TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
241      if (Idx == Piece.getOperandNo())
242        break;
243      ++Idx;
244
245      if (Info.isReadWrite()) {
246        if (Idx == Piece.getOperandNo())
247          break;
248        ++Idx;
249      }
250    }
251
252    for (unsigned i = 0, e = NS->getNumInputs(); i != e; ++i, ++ConstraintIdx) {
253      TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
254      if (Idx == Piece.getOperandNo())
255        break;
256      ++Idx;
257
258      if (Info.isReadWrite()) {
259        if (Idx == Piece.getOperandNo())
260          break;
261        ++Idx;
262      }
263    }
264
265    // Now that we have the right indexes go ahead and check.
266    StringLiteral *Literal = Constraints[ConstraintIdx];
267    const Type *Ty = Exprs[ConstraintIdx]->getType().getTypePtr();
268    if (Ty->isDependentType() || Ty->isIncompleteType())
269      continue;
270
271    unsigned Size = Context.getTypeSize(Ty);
272    if (!Context.getTargetInfo()
273          .validateConstraintModifier(Literal->getString(), Piece.getModifier(),
274                                      Size))
275      Diag(Exprs[ConstraintIdx]->getLocStart(),
276           diag::warn_asm_mismatched_size_modifier);
277  }
278
279  // Validate tied input operands for type mismatches.
280  for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
281    TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
282
283    // If this is a tied constraint, verify that the output and input have
284    // either exactly the same type, or that they are int/ptr operands with the
285    // same size (int/long, int*/long, are ok etc).
286    if (!Info.hasTiedOperand()) continue;
287
288    unsigned TiedTo = Info.getTiedOperand();
289    unsigned InputOpNo = i+NumOutputs;
290    Expr *OutputExpr = Exprs[TiedTo];
291    Expr *InputExpr = Exprs[InputOpNo];
292
293    if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent())
294      continue;
295
296    QualType InTy = InputExpr->getType();
297    QualType OutTy = OutputExpr->getType();
298    if (Context.hasSameType(InTy, OutTy))
299      continue;  // All types can be tied to themselves.
300
301    // Decide if the input and output are in the same domain (integer/ptr or
302    // floating point.
303    enum AsmDomain {
304      AD_Int, AD_FP, AD_Other
305    } InputDomain, OutputDomain;
306
307    if (InTy->isIntegerType() || InTy->isPointerType())
308      InputDomain = AD_Int;
309    else if (InTy->isRealFloatingType())
310      InputDomain = AD_FP;
311    else
312      InputDomain = AD_Other;
313
314    if (OutTy->isIntegerType() || OutTy->isPointerType())
315      OutputDomain = AD_Int;
316    else if (OutTy->isRealFloatingType())
317      OutputDomain = AD_FP;
318    else
319      OutputDomain = AD_Other;
320
321    // They are ok if they are the same size and in the same domain.  This
322    // allows tying things like:
323    //   void* to int*
324    //   void* to int            if they are the same size.
325    //   double to long double   if they are the same size.
326    //
327    uint64_t OutSize = Context.getTypeSize(OutTy);
328    uint64_t InSize = Context.getTypeSize(InTy);
329    if (OutSize == InSize && InputDomain == OutputDomain &&
330        InputDomain != AD_Other)
331      continue;
332
333    // If the smaller input/output operand is not mentioned in the asm string,
334    // then we can promote the smaller one to a larger input and the asm string
335    // won't notice.
336    bool SmallerValueMentioned = false;
337
338    // If this is a reference to the input and if the input was the smaller
339    // one, then we have to reject this asm.
340    if (isOperandMentioned(InputOpNo, Pieces)) {
341      // This is a use in the asm string of the smaller operand.  Since we
342      // codegen this by promoting to a wider value, the asm will get printed
343      // "wrong".
344      SmallerValueMentioned |= InSize < OutSize;
345    }
346    if (isOperandMentioned(TiedTo, Pieces)) {
347      // If this is a reference to the output, and if the output is the larger
348      // value, then it's ok because we'll promote the input to the larger type.
349      SmallerValueMentioned |= OutSize < InSize;
350    }
351
352    // If the smaller value wasn't mentioned in the asm string, and if the
353    // output was a register, just extend the shorter one to the size of the
354    // larger one.
355    if (!SmallerValueMentioned && InputDomain != AD_Other &&
356        OutputConstraintInfos[TiedTo].allowsRegister())
357      continue;
358
359    // Either both of the operands were mentioned or the smaller one was
360    // mentioned.  One more special case that we'll allow: if the tied input is
361    // integer, unmentioned, and is a constant, then we'll allow truncating it
362    // down to the size of the destination.
363    if (InputDomain == AD_Int && OutputDomain == AD_Int &&
364        !isOperandMentioned(InputOpNo, Pieces) &&
365        InputExpr->isEvaluatable(Context)) {
366      CastKind castKind =
367        (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast);
368      InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take();
369      Exprs[InputOpNo] = InputExpr;
370      NS->setInputExpr(i, InputExpr);
371      continue;
372    }
373
374    Diag(InputExpr->getLocStart(),
375         diag::err_asm_tying_incompatible_types)
376      << InTy << OutTy << OutputExpr->getSourceRange()
377      << InputExpr->getSourceRange();
378    return StmtError();
379  }
380
381  return Owned(NS);
382}
383
384// getSpelling - Get the spelling of the AsmTok token.
385static StringRef getSpelling(Sema &SemaRef, Token AsmTok) {
386  StringRef Asm;
387  SmallString<512> TokenBuf;
388  TokenBuf.resize(512);
389  bool StringInvalid = false;
390  Asm = SemaRef.PP.getSpelling(AsmTok, TokenBuf, &StringInvalid);
391  assert (!StringInvalid && "Expected valid string!");
392  return Asm;
393}
394
395// Build the inline assembly string.  Returns true on error.
396static bool buildMSAsmString(Sema &SemaRef,
397                             SourceLocation AsmLoc,
398                             ArrayRef<Token> AsmToks,
399                             SmallVectorImpl<unsigned> &TokOffsets,
400                             std::string &AsmString) {
401  assert (!AsmToks.empty() && "Didn't expect an empty AsmToks!");
402
403  SmallString<512> Asm;
404  for (unsigned i = 0, e = AsmToks.size(); i < e; ++i) {
405    bool isNewAsm = ((i == 0) ||
406                     AsmToks[i].isAtStartOfLine() ||
407                     AsmToks[i].is(tok::kw_asm));
408    if (isNewAsm) {
409      if (i != 0)
410        Asm += "\n\t";
411
412      if (AsmToks[i].is(tok::kw_asm)) {
413        i++; // Skip __asm
414        if (i == e) {
415          SemaRef.Diag(AsmLoc, diag::err_asm_empty);
416          return true;
417        }
418
419      }
420    }
421
422    if (i && AsmToks[i].hasLeadingSpace() && !isNewAsm)
423      Asm += ' ';
424
425    StringRef Spelling = getSpelling(SemaRef, AsmToks[i]);
426    Asm += Spelling;
427    TokOffsets.push_back(Asm.size());
428  }
429  AsmString = Asm.str();
430  return false;
431}
432
433namespace {
434
435class MCAsmParserSemaCallbackImpl : public llvm::MCAsmParserSemaCallback {
436  Sema &SemaRef;
437  SourceLocation AsmLoc;
438  ArrayRef<Token> AsmToks;
439  ArrayRef<unsigned> TokOffsets;
440
441public:
442  MCAsmParserSemaCallbackImpl(Sema &Ref, SourceLocation Loc,
443                              ArrayRef<Token> Toks,
444                              ArrayRef<unsigned> Offsets)
445    : SemaRef(Ref), AsmLoc(Loc), AsmToks(Toks), TokOffsets(Offsets) { }
446  ~MCAsmParserSemaCallbackImpl() {}
447
448  void *LookupInlineAsmIdentifier(StringRef Name, void *SrcLoc,
449                                  unsigned &Length, unsigned &Size,
450                                  unsigned &Type, bool &IsVarDecl){
451    SourceLocation Loc = SourceLocation::getFromPtrEncoding(SrcLoc);
452
453    NamedDecl *OpDecl = SemaRef.LookupInlineAsmIdentifier(Name, Loc, Length,
454                                                          Size, Type,
455                                                          IsVarDecl);
456    return static_cast<void *>(OpDecl);
457  }
458
459  bool LookupInlineAsmField(StringRef Base, StringRef Member,
460                            unsigned &Offset) {
461    return SemaRef.LookupInlineAsmField(Base, Member, Offset, AsmLoc);
462  }
463
464  static void MSAsmDiagHandlerCallback(const llvm::SMDiagnostic &D,
465                                       void *Context) {
466    ((MCAsmParserSemaCallbackImpl*)Context)->MSAsmDiagHandler(D);
467  }
468  void MSAsmDiagHandler(const llvm::SMDiagnostic &D) {
469    // Compute an offset into the inline asm buffer.
470    // FIXME: This isn't right if .macro is involved (but hopefully, no
471    // real-world code does that).
472    const llvm::SourceMgr &LSM = *D.getSourceMgr();
473    const llvm::MemoryBuffer *LBuf =
474    LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
475    unsigned Offset = D.getLoc().getPointer()  - LBuf->getBufferStart();
476
477    // Figure out which token that offset points into.
478    const unsigned *OffsetPtr =
479        std::lower_bound(TokOffsets.begin(), TokOffsets.end(), Offset);
480    unsigned TokIndex = OffsetPtr - TokOffsets.begin();
481
482    // If we come up with an answer which seems sane, use it; otherwise,
483    // just point at the __asm keyword.
484    // FIXME: Assert the answer is sane once we handle .macro correctly.
485    SourceLocation Loc = AsmLoc;
486    if (TokIndex < AsmToks.size()) {
487      const Token *Tok = &AsmToks[TokIndex];
488      Loc = Tok->getLocation();
489      Loc = Loc.getLocWithOffset(Offset - (*OffsetPtr - Tok->getLength()));
490    }
491    SemaRef.Diag(Loc, diag::err_inline_ms_asm_parsing) << D.getMessage();
492  }
493};
494
495}
496
497NamedDecl *Sema::LookupInlineAsmIdentifier(StringRef Name, SourceLocation Loc,
498                                           unsigned &Length, unsigned &Size,
499                                           unsigned &Type, bool &IsVarDecl) {
500  Length = 1;
501  Size = 0;
502  Type = 0;
503  IsVarDecl = false;
504  LookupResult Result(*this, &Context.Idents.get(Name), Loc,
505                      Sema::LookupOrdinaryName);
506
507  if (!LookupName(Result, getCurScope())) {
508    // If we don't find anything, return null; the AsmParser will assume
509    // it is a label of some sort.
510    return 0;
511  }
512
513  if (!Result.isSingleResult()) {
514    // FIXME: Diagnose result.
515    return 0;
516  }
517
518  NamedDecl *ND = Result.getFoundDecl();
519  if (isa<VarDecl>(ND) || isa<FunctionDecl>(ND)) {
520    if (VarDecl *Var = dyn_cast<VarDecl>(ND)) {
521      Type = Context.getTypeInfo(Var->getType()).first;
522      QualType Ty = Var->getType();
523      if (Ty->isArrayType()) {
524        const ArrayType *ATy = Context.getAsArrayType(Ty);
525        Length = Type / Context.getTypeInfo(ATy->getElementType()).first;
526        Type /= Length; // Type is in terms of a single element.
527      }
528      Type /= 8; // Type is in terms of bits, but we want bytes.
529      Size = Length * Type;
530      IsVarDecl = true;
531    }
532    return ND;
533  }
534
535  // FIXME: Handle other kinds of results? (FieldDecl, etc.)
536  // FIXME: Diagnose if we find something we can't handle, like a typedef.
537  return 0;
538}
539
540bool Sema::LookupInlineAsmField(StringRef Base, StringRef Member,
541                                unsigned &Offset, SourceLocation AsmLoc) {
542  Offset = 0;
543  LookupResult BaseResult(*this, &Context.Idents.get(Base), SourceLocation(),
544                          LookupOrdinaryName);
545
546  if (!LookupName(BaseResult, getCurScope()))
547    return true;
548
549  if (!BaseResult.isSingleResult())
550    return true;
551
552  NamedDecl *FoundDecl = BaseResult.getFoundDecl();
553  const RecordType *RT = 0;
554  if (VarDecl *VD = dyn_cast<VarDecl>(FoundDecl)) {
555    RT = VD->getType()->getAs<RecordType>();
556  } else if (TypedefDecl *TD = dyn_cast<TypedefDecl>(FoundDecl)) {
557    RT = TD->getUnderlyingType()->getAs<RecordType>();
558  }
559  if (!RT)
560    return true;
561
562  if (RequireCompleteType(AsmLoc, QualType(RT, 0), 0))
563    return true;
564
565  LookupResult FieldResult(*this, &Context.Idents.get(Member), SourceLocation(),
566                           LookupMemberName);
567
568  if (!LookupQualifiedName(FieldResult, RT->getDecl()))
569    return true;
570
571  // FIXME: Handle IndirectFieldDecl?
572  FieldDecl *FD = dyn_cast<FieldDecl>(FieldResult.getFoundDecl());
573  if (!FD)
574    return true;
575
576  const ASTRecordLayout &RL = Context.getASTRecordLayout(RT->getDecl());
577  unsigned i = FD->getFieldIndex();
578  CharUnits Result = Context.toCharUnitsFromBits(RL.getFieldOffset(i));
579  Offset = (unsigned)Result.getQuantity();
580
581  return false;
582}
583
584StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
585                                ArrayRef<Token> AsmToks,SourceLocation EndLoc) {
586  SmallVector<IdentifierInfo*, 4> Names;
587  SmallVector<StringRef, 4> ConstraintRefs;
588  SmallVector<Expr*, 4> Exprs;
589  SmallVector<StringRef, 4> ClobberRefs;
590
591  llvm::Triple TheTriple = Context.getTargetInfo().getTriple();
592  llvm::Triple::ArchType ArchTy = TheTriple.getArch();
593  bool UnsupportedArch = ArchTy != llvm::Triple::x86 &&
594    ArchTy != llvm::Triple::x86_64;
595  if (UnsupportedArch)
596    Diag(AsmLoc, diag::err_msasm_unsupported_arch) << TheTriple.getArchName();
597
598  // Empty asm statements don't need to instantiate the AsmParser, etc.
599  if (UnsupportedArch || AsmToks.empty()) {
600    StringRef EmptyAsmStr;
601    MSAsmStmt *NS =
602      new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, /*IsSimple*/ true,
603                              /*IsVolatile*/ true, AsmToks, /*NumOutputs*/ 0,
604                              /*NumInputs*/ 0, Names, ConstraintRefs, Exprs,
605                              EmptyAsmStr, ClobberRefs, EndLoc);
606    return Owned(NS);
607  }
608
609  std::string AsmString;
610  SmallVector<unsigned, 8> TokOffsets;
611  if (buildMSAsmString(*this, AsmLoc, AsmToks, TokOffsets, AsmString))
612    return StmtError();
613
614  // Get the target specific parser.
615  std::string Error;
616  const std::string &TT = TheTriple.getTriple();
617  const llvm::Target *TheTarget(llvm::TargetRegistry::lookupTarget(TT, Error));
618
619  OwningPtr<llvm::MCAsmInfo> MAI(TheTarget->createMCAsmInfo(TT));
620  OwningPtr<llvm::MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TT));
621  OwningPtr<llvm::MCObjectFileInfo> MOFI(new llvm::MCObjectFileInfo());
622  OwningPtr<llvm::MCSubtargetInfo>
623    STI(TheTarget->createMCSubtargetInfo(TT, "", ""));
624
625  llvm::SourceMgr SrcMgr;
626  llvm::MCContext Ctx(*MAI, *MRI, MOFI.get(), &SrcMgr);
627  llvm::MemoryBuffer *Buffer =
628    llvm::MemoryBuffer::getMemBuffer(AsmString, "<inline asm>");
629
630  // Tell SrcMgr about this buffer, which is what the parser will pick up.
631  SrcMgr.AddNewSourceBuffer(Buffer, llvm::SMLoc());
632
633  OwningPtr<llvm::MCStreamer> Str(createNullStreamer(Ctx));
634  OwningPtr<llvm::MCAsmParser>
635    Parser(createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
636  OwningPtr<llvm::MCTargetAsmParser>
637    TargetParser(TheTarget->createMCAsmParser(*STI, *Parser));
638
639  // Get the instruction descriptor.
640  const llvm::MCInstrInfo *MII = TheTarget->createMCInstrInfo();
641  llvm::MCInstPrinter *IP =
642    TheTarget->createMCInstPrinter(1, *MAI, *MII, *MRI, *STI);
643
644  // Change to the Intel dialect.
645  Parser->setAssemblerDialect(1);
646  Parser->setTargetParser(*TargetParser.get());
647  Parser->setParsingInlineAsm(true);
648  TargetParser->setParsingInlineAsm(true);
649
650  MCAsmParserSemaCallbackImpl MCAPSI(*this, AsmLoc, AsmToks, TokOffsets);
651  TargetParser->setSemaCallback(&MCAPSI);
652  SrcMgr.setDiagHandler(MCAsmParserSemaCallbackImpl::MSAsmDiagHandlerCallback,
653                        &MCAPSI);
654
655  unsigned NumOutputs;
656  unsigned NumInputs;
657  std::string AsmStringIR;
658  SmallVector<std::pair<void *, bool>, 4> OpDecls;
659  SmallVector<std::string, 4> Constraints;
660  SmallVector<std::string, 4> Clobbers;
661  if (Parser->parseMSInlineAsm(AsmLoc.getPtrEncoding(), AsmStringIR,
662                               NumOutputs, NumInputs, OpDecls, Constraints,
663                               Clobbers, MII, IP, MCAPSI))
664    return StmtError();
665
666  // Build the vector of clobber StringRefs.
667  unsigned NumClobbers = Clobbers.size();
668  ClobberRefs.resize(NumClobbers);
669  for (unsigned i = 0; i != NumClobbers; ++i)
670    ClobberRefs[i] = StringRef(Clobbers[i]);
671
672  // Recast the void pointers and build the vector of constraint StringRefs.
673  unsigned NumExprs = NumOutputs + NumInputs;
674  Names.resize(NumExprs);
675  ConstraintRefs.resize(NumExprs);
676  Exprs.resize(NumExprs);
677  for (unsigned i = 0, e = NumExprs; i != e; ++i) {
678    NamedDecl *OpDecl = static_cast<NamedDecl *>(OpDecls[i].first);
679    if (!OpDecl)
680      return StmtError();
681
682    DeclarationNameInfo NameInfo(OpDecl->getDeclName(), AsmLoc);
683    ExprResult OpExpr = BuildDeclarationNameExpr(CXXScopeSpec(), NameInfo,
684                                                 OpDecl);
685    if (OpExpr.isInvalid())
686      return StmtError();
687
688    // Need address of variable.
689    if (OpDecls[i].second)
690      OpExpr = BuildUnaryOp(getCurScope(), AsmLoc, clang::UO_AddrOf,
691                            OpExpr.take());
692
693    Names[i] = OpDecl->getIdentifier();
694    ConstraintRefs[i] = StringRef(Constraints[i]);
695    Exprs[i] = OpExpr.take();
696  }
697
698  bool IsSimple = NumExprs > 0;
699  MSAsmStmt *NS =
700    new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple,
701                            /*IsVolatile*/ true, AsmToks, NumOutputs, NumInputs,
702                            Names, ConstraintRefs, Exprs, AsmStringIR,
703                            ClobberRefs, EndLoc);
704  return Owned(NS);
705}
706