C++ Sema::getLangOpts方法代码示例

// Do we know that we will eventually codegen the given function?
static bool IsKnownEmitted(Sema &S, FunctionDecl *FD) {
  // Templates are emitted when they're instantiated.
  if (FD->isDependentContext())
    return false;

  // When compiling for device, host functions are never emitted.  Similarly,
  // when compiling for host, device and global functions are never emitted.
  // (Technically, we do emit a host-side stub for global functions, but this
  // doesn't count for our purposes here.)
  Sema::CUDAFunctionTarget T = S.IdentifyCUDATarget(FD);
  if (S.getLangOpts().CUDAIsDevice && T == Sema::CFT_Host)
    return false;
  if (!S.getLangOpts().CUDAIsDevice &&
      (T == Sema::CFT_Device || T == Sema::CFT_Global))
    return false;

  // Check whether this function is externally visible -- if so, it's
  // known-emitted.
  //
  // We have to check the GVA linkage of the function's *definition* -- if we
  // only have a declaration, we don't know whether or not the function will be
  // emitted, because (say) the definition could include "inline".
  FunctionDecl *Def = FD->getDefinition();

  if (Def &&
      !isDiscardableGVALinkage(S.getASTContext().GetGVALinkageForFunction(Def)))
    return true;

  // Otherwise, the function is known-emitted if it's in our set of
  // known-emitted functions.
  return S.DeviceKnownEmittedFns.count(FD) > 0;
}

bool DeclSpec::SetStorageClassSpec(Sema &S, SCS SC, SourceLocation Loc,
                                   const char *&PrevSpec,
                                   unsigned &DiagID,
                                   const PrintingPolicy &Policy) {
  // OpenCL v1.1 s6.8g: "The extern, static, auto and register storage-class
  // specifiers are not supported.
  // It seems sensible to prohibit private_extern too
  // The cl_clang_storage_class_specifiers extension enables support for
  // these storage-class specifiers.
  // OpenCL v1.2 s6.8 changes this to "The auto and register storage-class
  // specifiers are not supported."
  if (S.getLangOpts().OpenCL &&
      !S.getOpenCLOptions().cl_clang_storage_class_specifiers) {
    switch (SC) {
    case SCS_extern:
    case SCS_private_extern:
    case SCS_static:
        if (S.getLangOpts().OpenCLVersion < 120) {
          DiagID   = diag::err_opencl_unknown_type_specifier;
          PrevSpec = getSpecifierName(SC);
          return true;
        }
        break;
    case SCS_auto:
    case SCS_register:
      DiagID   = diag::err_opencl_unknown_type_specifier;
      PrevSpec = getSpecifierName(SC);
      return true;
    default:
      break;
    }
  }

  if (StorageClassSpec != SCS_unspecified) {
    // Maybe this is an attempt to use C++11 'auto' outside of C++11 mode.
    bool isInvalid = true;
    if (TypeSpecType == TST_unspecified && S.getLangOpts().CPlusPlus) {
      if (SC == SCS_auto)
        return SetTypeSpecType(TST_auto, Loc, PrevSpec, DiagID, Policy);
      if (StorageClassSpec == SCS_auto) {
        isInvalid = SetTypeSpecType(TST_auto, StorageClassSpecLoc,
                                    PrevSpec, DiagID, Policy);
        assert(!isInvalid && "auto SCS -> TST recovery failed");
      }
    }

    // Changing storage class is allowed only if the previous one
    // was the 'extern' that is part of a linkage specification and
    // the new storage class is 'typedef'.
    if (isInvalid &&
        !(SCS_extern_in_linkage_spec &&
          StorageClassSpec == SCS_extern &&
          SC == SCS_typedef))
      return BadSpecifier(SC, (SCS)StorageClassSpec, PrevSpec, DiagID);
  }
  StorageClassSpec = SC;
  StorageClassSpecLoc = Loc;
  assert((unsigned)SC == StorageClassSpec && "SCS constants overflow bitfield");
  return false;
}

/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
/// ignore "noop" casts in places where an lvalue is required by an inline asm.
/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
/// provide a strong guidance to not use it.
///
/// This method checks to see if the argument is an acceptable l-value and
/// returns false if it is a case we can handle.
static bool CheckAsmLValue(const Expr *E, Sema &S) {
  // Type dependent expressions will be checked during instantiation.
  if (E->isTypeDependent())
    return false;

  if (E->isLValue())
    return false;  // Cool, this is an lvalue.

  // Okay, this is not an lvalue, but perhaps it is the result of a cast that we
  // are supposed to allow.
  const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
  if (E != E2 && E2->isLValue()) {
    if (!S.getLangOpts().HeinousExtensions)
      S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
        << E->getSourceRange();
    else
      S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
        << E->getSourceRange();
    // Accept, even if we emitted an error diagnostic.
    return false;
  }

  // None of the above, just randomly invalid non-lvalue.
  return true;
}

static void HandleDLLImportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
  // Attribute can be applied only to functions or variables.
  FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
  if (!FD && !isa<VarDecl>(D)) {
    // Apparently Visual C++ thinks it is okay to not emit a warning
    // in this case, so only emit a warning when -fms-extensions is not
    // specified.
    if (!S.getLangOpts().MicrosoftExt)
      S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
        << Attr.getName() << 2 /*variable and function*/;
    return;
  }

  // Currently, the dllimport attribute is ignored for inlined functions.
  // Warning is emitted.
  if (FD && FD->isInlineSpecified()) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
    return;
  }

  unsigned Index = Attr.getAttributeSpellingListIndex();
  DLLImportAttr *NewAttr = S.mergeDLLImportAttr(D, Attr.getRange(), Index);
  if (NewAttr)
    D->addAttr(NewAttr);
}

static void EraseUnwantedCUDAMatchesImpl(Sema &S, const FunctionDecl *Caller,
                                         llvm::SmallVectorImpl<T> &Matches,
                                         FetchDeclFn FetchDecl) {
  assert(S.getLangOpts().CUDATargetOverloads &&
         "Should not be called w/o enabled target overloads.");
  if (Matches.size() <= 1)
    return;

  // Find the best call preference among the functions in Matches.
  Sema::CUDAFunctionPreference P, BestCFP = Sema::CFP_Never;
  for (auto const &Match : Matches) {
    P = S.IdentifyCUDAPreference(Caller, FetchDecl(Match));
    if (P > BestCFP)
      BestCFP = P;
  }

  // Erase all functions with lower priority.
  for (unsigned I = 0, N = Matches.size(); I != N;)
    if (S.IdentifyCUDAPreference(Caller, FetchDecl(Matches[I])) < BestCFP) {
      Matches[I] = Matches[--N];
      Matches.resize(N);
    } else {
      ++I;
    }
}

// Returns true on failure.
static bool
LookupMemberExprInRecord(Sema &SemaRef, LookupResult &R, 
                         //SourceRange BaseRange,
                         const StructType *STy,
                         SourceLocation OpLoc) {
  StructTypeDecl *SDecl = STy->getDecl();
  DeclContext *DC = SDecl;

  // The record definition is complete, now look up the member.
  SemaRef.LookupQualifiedName(R, DC);

  if (!R.empty())
    return false;

#if 0
  // We didn't find anything with the given name, so try to correct
  // for typos.
  DeclarationName Name = R.getLookupName();
  RecordMemberExprValidatorCCC Validator;
  TypoCorrection Corrected = SemaRef.CorrectTypo(R.getLookupNameInfo(),
                                                 R.getLookupKind(), NULL,
                                                 &SS, Validator, DC);
  R.clear();
  if (NamedDecl *ND = Corrected.getCorrectionDecl()) {
    std::string CorrectedStr(
        Corrected.getAsString(SemaRef.getLangOpts()));
    std::string CorrectedQuotedStr(
        Corrected.getQuoted(SemaRef.getLangOpts()));
    R.setLookupName(Corrected.getCorrection());
    R.addDecl(ND);
    SemaRef.Diag(R.getNameLoc(), diag::err_no_member_suggest)
      << Name << DC << CorrectedQuotedStr << SS.getRange()
      << FixItHint::CreateReplacement(Corrected.getCorrectionRange(),
                                      CorrectedStr);
    SemaRef.Diag(ND->getLocation(), diag::note_previous_decl)
      << ND->getDeclName();
  }
#endif

  // FIXME: Is this right? (also in clang)
  return false;
}

// Do we know that we will eventually codegen the given function?
static bool IsKnownEmitted(Sema &S, FunctionDecl *FD) {
  // Templates are emitted when they're instantiated.
  if (FD->isDependentContext())
    return false;

  // When compiling for device, host functions are never emitted.  Similarly,
  // when compiling for host, device and global functions are never emitted.
  // (Technically, we do emit a host-side stub for global functions, but this
  // doesn't count for our purposes here.)
  Sema::CUDAFunctionTarget T = S.IdentifyCUDATarget(FD);
  if (S.getLangOpts().CUDAIsDevice && T == Sema::CFT_Host)
    return false;
  if (!S.getLangOpts().CUDAIsDevice &&
      (T == Sema::CFT_Device || T == Sema::CFT_Global))
    return false;

  // Externally-visible and similar functions are always emitted.
  if (!isDiscardableGVALinkage(S.getASTContext().GetGVALinkageForFunction(FD)))
    return true;

  // Otherwise, the function is known-emitted if it's in our set of
  // known-emitted functions.
  return S.CUDAKnownEmittedFns.count(FD) > 0;
}

/// Return true if a particular note should be downgraded to a compatibility
/// warning in C++11 mode.
static bool IsCXX98CompatWarning(Sema &S, unsigned InDiagNote) {
  return S.getLangOpts().CPlusPlus0x &&
         InDiagNote == diag::note_protected_by_variable_non_pod;
}

static unsigned long long getContextsForContextKind(
                                          enum CodeCompletionContext::Kind kind, 
                                                    Sema &S) {
  unsigned long long contexts = 0;
  switch (kind) {
    case CodeCompletionContext::CCC_OtherWithMacros: {
      //We can allow macros here, but we don't know what else is permissible
      //So we'll say the only thing permissible are macros
      contexts = CXCompletionContext_MacroName;
      break;
    }
    case CodeCompletionContext::CCC_TopLevel:
    case CodeCompletionContext::CCC_ObjCIvarList:
    case CodeCompletionContext::CCC_ClassStructUnion:
    case CodeCompletionContext::CCC_Type: {
      contexts = CXCompletionContext_AnyType | 
                 CXCompletionContext_ObjCInterface;
      if (S.getLangOpts().CPlusPlus) {
        contexts |= CXCompletionContext_EnumTag |
                    CXCompletionContext_UnionTag |
                    CXCompletionContext_StructTag |
                    CXCompletionContext_ClassTag |
                    CXCompletionContext_NestedNameSpecifier;
      }
      break;
    }
    case CodeCompletionContext::CCC_Statement: {
      contexts = CXCompletionContext_AnyType |
                 CXCompletionContext_ObjCInterface |
                 CXCompletionContext_AnyValue;
      if (S.getLangOpts().CPlusPlus) {
        contexts |= CXCompletionContext_EnumTag |
                    CXCompletionContext_UnionTag |
                    CXCompletionContext_StructTag |
                    CXCompletionContext_ClassTag |
                    CXCompletionContext_NestedNameSpecifier;
      }
      break;
    }
    case CodeCompletionContext::CCC_Expression: {
      contexts = CXCompletionContext_AnyValue;
      if (S.getLangOpts().CPlusPlus) {
        contexts |= CXCompletionContext_AnyType |
                    CXCompletionContext_ObjCInterface |
                    CXCompletionContext_EnumTag |
                    CXCompletionContext_UnionTag |
                    CXCompletionContext_StructTag |
                    CXCompletionContext_ClassTag |
                    CXCompletionContext_NestedNameSpecifier;
      }
      break;
    }
    case CodeCompletionContext::CCC_ObjCMessageReceiver: {
      contexts = CXCompletionContext_ObjCObjectValue |
                 CXCompletionContext_ObjCSelectorValue |
                 CXCompletionContext_ObjCInterface;
      if (S.getLangOpts().CPlusPlus) {
        contexts |= CXCompletionContext_CXXClassTypeValue |
                    CXCompletionContext_AnyType |
                    CXCompletionContext_EnumTag |
                    CXCompletionContext_UnionTag |
                    CXCompletionContext_StructTag |
                    CXCompletionContext_ClassTag |
                    CXCompletionContext_NestedNameSpecifier;
      }
      break;
    }
    case CodeCompletionContext::CCC_DotMemberAccess: {
      contexts = CXCompletionContext_DotMemberAccess;
      break;
    }
    case CodeCompletionContext::CCC_ArrowMemberAccess: {
      contexts = CXCompletionContext_ArrowMemberAccess;
      break;
    }
    case CodeCompletionContext::CCC_ObjCPropertyAccess: {
      contexts = CXCompletionContext_ObjCPropertyAccess;
      break;
    }
    case CodeCompletionContext::CCC_EnumTag: {
      contexts = CXCompletionContext_EnumTag |
                 CXCompletionContext_NestedNameSpecifier;
      break;
    }
    case CodeCompletionContext::CCC_UnionTag: {
      contexts = CXCompletionContext_UnionTag |
                 CXCompletionContext_NestedNameSpecifier;
      break;
    }
    case CodeCompletionContext::CCC_ClassOrStructTag: {
      contexts = CXCompletionContext_StructTag |
                 CXCompletionContext_ClassTag |
                 CXCompletionContext_NestedNameSpecifier;
      break;
    }
    case CodeCompletionContext::CCC_ObjCProtocolName: {
      contexts = CXCompletionContext_ObjCProtocol;
      break;
    }
    case CodeCompletionContext::CCC_Namespace: {
//.........这里部分代码省略.........

/// Finish - This does final analysis of the declspec, rejecting things like
/// "_Imaginary" (lacking an FP type).  This returns a diagnostic to issue or
/// diag::NUM_DIAGNOSTICS if there is no error.  After calling this method,
/// DeclSpec is guaranteed self-consistent, even if an error occurred.
void DeclSpec::Finish(Sema &S, const PrintingPolicy &Policy) {
  // Before possibly changing their values, save specs as written.
  SaveWrittenBuiltinSpecs();

  // Check the type specifier components first.

  // If decltype(auto) is used, no other type specifiers are permitted.
  if (TypeSpecType == TST_decltype_auto &&
      (TypeSpecWidth != TSW_unspecified ||
       TypeSpecComplex != TSC_unspecified ||
       TypeSpecSign != TSS_unspecified ||
       TypeAltiVecVector || TypeAltiVecPixel || TypeAltiVecBool ||
       TypeQualifiers)) {
    const unsigned NumLocs = 9;
    SourceLocation ExtraLocs[NumLocs] = {
      TSWLoc, TSCLoc, TSSLoc, AltiVecLoc,
      TQ_constLoc, TQ_restrictLoc, TQ_volatileLoc, TQ_atomicLoc, TQ_unalignedLoc
    };
    FixItHint Hints[NumLocs];
    SourceLocation FirstLoc;
    for (unsigned I = 0; I != NumLocs; ++I) {
      if (ExtraLocs[I].isValid()) {
        if (FirstLoc.isInvalid() ||
            S.getSourceManager().isBeforeInTranslationUnit(ExtraLocs[I],
                                                           FirstLoc))
          FirstLoc = ExtraLocs[I];
        Hints[I] = FixItHint::CreateRemoval(ExtraLocs[I]);
      }
    }
    TypeSpecWidth = TSW_unspecified;
    TypeSpecComplex = TSC_unspecified;
    TypeSpecSign = TSS_unspecified;
    TypeAltiVecVector = TypeAltiVecPixel = TypeAltiVecBool = false;
    TypeQualifiers = 0;
    S.Diag(TSTLoc, diag::err_decltype_auto_cannot_be_combined)
      << Hints[0] << Hints[1] << Hints[2] << Hints[3]
      << Hints[4] << Hints[5] << Hints[6] << Hints[7];
  }

  // Validate and finalize AltiVec vector declspec.
  if (TypeAltiVecVector) {
    if (TypeAltiVecBool) {
      // Sign specifiers are not allowed with vector bool. (PIM 2.1)
      if (TypeSpecSign != TSS_unspecified) {
        S.Diag(TSSLoc, diag::err_invalid_vector_bool_decl_spec)
          << getSpecifierName((TSS)TypeSpecSign);
      }

      // Only char/int are valid with vector bool. (PIM 2.1)
      if (((TypeSpecType != TST_unspecified) && (TypeSpecType != TST_char) &&
           (TypeSpecType != TST_int)) || TypeAltiVecPixel) {
        S.Diag(TSTLoc, diag::err_invalid_vector_bool_decl_spec)
          << (TypeAltiVecPixel ? "__pixel" :
                                 getSpecifierName((TST)TypeSpecType, Policy));
      }

      // Only 'short' and 'long long' are valid with vector bool. (PIM 2.1)
      if ((TypeSpecWidth != TSW_unspecified) && (TypeSpecWidth != TSW_short) &&
          (TypeSpecWidth != TSW_longlong))
        S.Diag(TSWLoc, diag::err_invalid_vector_bool_decl_spec)
          << getSpecifierName((TSW)TypeSpecWidth);

      // vector bool long long requires VSX support or ZVector.
      if ((TypeSpecWidth == TSW_longlong) &&
          (!S.Context.getTargetInfo().hasFeature("vsx")) &&
          (!S.Context.getTargetInfo().hasFeature("power8-vector")) &&
          !S.getLangOpts().ZVector)
        S.Diag(TSTLoc, diag::err_invalid_vector_long_long_decl_spec);

      // Elements of vector bool are interpreted as unsigned. (PIM 2.1)
      if ((TypeSpecType == TST_char) || (TypeSpecType == TST_int) ||
          (TypeSpecWidth != TSW_unspecified))
        TypeSpecSign = TSS_unsigned;
    } else if (TypeSpecType == TST_double) {
      // vector long double and vector long long double are never allowed.
      // vector double is OK for Power7 and later, and ZVector.
      if (TypeSpecWidth == TSW_long || TypeSpecWidth == TSW_longlong)
        S.Diag(TSWLoc, diag::err_invalid_vector_long_double_decl_spec);
      else if (!S.Context.getTargetInfo().hasFeature("vsx") &&
               !S.getLangOpts().ZVector)
        S.Diag(TSTLoc, diag::err_invalid_vector_double_decl_spec);
    } else if (TypeSpecType == TST_float) {
      // vector float is unsupported for ZVector.
      if (S.getLangOpts().ZVector)
        S.Diag(TSTLoc, diag::err_invalid_vector_float_decl_spec);
    } else if (TypeSpecWidth == TSW_long) {
      // vector long is unsupported for ZVector and deprecated for AltiVec.
      if (S.getLangOpts().ZVector)
        S.Diag(TSWLoc, diag::err_invalid_vector_long_decl_spec);
      else
        S.Diag(TSWLoc, diag::warn_vector_long_decl_spec_combination)
          << getSpecifierName((TST)TypeSpecType, Policy);
    }

    if (TypeAltiVecPixel) {
      //TODO: perform validation
//.........这里部分代码省略.........

void clang::ParseAST(Sema &S, bool PrintStats, bool SkipFunctionBodies) {
  // Collect global stats on Decls/Stmts (until we have a module streamer).
  if (PrintStats) {
    Decl::EnableStatistics();
    Stmt::EnableStatistics();
  }

  // Also turn on collection of stats inside of the Sema object.
  bool OldCollectStats = PrintStats;
  std::swap(OldCollectStats, S.CollectStats);

  ASTConsumer *Consumer = &S.getASTConsumer();

  OwningPtr<Parser> ParseOP(new Parser(S.getPreprocessor(), S,
                                       SkipFunctionBodies));
  Parser &P = *ParseOP.get();

  PrettyStackTraceParserEntry CrashInfo(P);

  // Recover resources if we crash before exiting this method.
  llvm::CrashRecoveryContextCleanupRegistrar<Parser>
    CleanupParser(ParseOP.get());

  S.getPreprocessor().EnterMainSourceFile();
  P.Initialize();
  S.Initialize();

  // C11 6.9p1 says translation units must have at least one top-level
  // declaration. C++ doesn't have this restriction. We also don't want to
  // complain if we have a precompiled header, although technically if the PCH
  // is empty we should still emit the (pedantic) diagnostic.
  Parser::DeclGroupPtrTy ADecl;
  ExternalASTSource *External = S.getASTContext().getExternalSource();
  if (External)
    External->StartTranslationUnit(Consumer);

  if (P.ParseTopLevelDecl(ADecl)) {
    if (!External && !S.getLangOpts().CPlusPlus)
      P.Diag(diag::ext_empty_translation_unit);
  } else {
    do {
      // If we got a null return and something *was* parsed, ignore it.  This
      // is due to a top-level semicolon, an action override, or a parse error
      // skipping something.
      if (ADecl && !Consumer->HandleTopLevelDecl(ADecl.get()))
	return;
    } while (!P.ParseTopLevelDecl(ADecl));
  }

  // Process any TopLevelDecls generated by #pragma weak.
  for (SmallVector<Decl*,2>::iterator
       I = S.WeakTopLevelDecls().begin(),
       E = S.WeakTopLevelDecls().end(); I != E; ++I)
    Consumer->HandleTopLevelDecl(DeclGroupRef(*I));
  
  Consumer->HandleTranslationUnit(S.getASTContext());

  std::swap(OldCollectStats, S.CollectStats);
  if (PrintStats) {
    llvm::errs() << "\nSTATISTICS:\n";
    P.getActions().PrintStats();
    S.getASTContext().PrintStats();
    Decl::PrintStats();
    Stmt::PrintStats();
    Consumer->PrintStats();
  }
}