path: root/lib/Sema/SemaType.cpp

//===--- SemaType.cpp - Semantic Analysis for Types -----------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements type-related semantic analysis.
//
//===----------------------------------------------------------------------===//

#include "Sema.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Expr.h"
#include "clang/Parse/DeclSpec.h"
using namespace clang;

/// \brief Convert the specified declspec to the appropriate type
/// object.
/// \param DS  the declaration specifiers
/// \returns The type described by the declaration specifiers, or NULL
/// if there was an error.
QualType Sema::ConvertDeclSpecToType(const DeclSpec &DS) {
  // FIXME: Should move the logic from DeclSpec::Finish to here for validity
  // checking.
  QualType Result;
  
  switch (DS.getTypeSpecType()) {
  case DeclSpec::TST_void:
    Result = Context.VoidTy;
    break;
  case DeclSpec::TST_char:
    if (DS.getTypeSpecSign() == DeclSpec::TSS_unspecified)
      Result = Context.CharTy;
    else if (DS.getTypeSpecSign() == DeclSpec::TSS_signed)
      Result = Context.SignedCharTy;
    else {
      assert(DS.getTypeSpecSign() == DeclSpec::TSS_unsigned &&
             "Unknown TSS value");
      Result = Context.UnsignedCharTy;
    }
    break;
  case DeclSpec::TST_wchar:
    if (DS.getTypeSpecSign() == DeclSpec::TSS_unspecified)
      Result = Context.WCharTy;
    else if (DS.getTypeSpecSign() == DeclSpec::TSS_signed) {
      Diag(DS.getTypeSpecSignLoc(), diag::ext_invalid_sign_spec)
        << DS.getSpecifierName(DS.getTypeSpecType());
      Result = Context.getSignedWCharType();
    } else {
      assert(DS.getTypeSpecSign() == DeclSpec::TSS_unsigned &&
        "Unknown TSS value");
      Diag(DS.getTypeSpecSignLoc(), diag::ext_invalid_sign_spec)
        << DS.getSpecifierName(DS.getTypeSpecType());
      Result = Context.getUnsignedWCharType();
    }
    break;
  case DeclSpec::TST_unspecified:
    // "<proto1,proto2>" is an objc qualified ID with a missing id.
    if (DeclSpec::ProtocolQualifierListTy PQ = DS.getProtocolQualifiers()) {
      Result = Context.getObjCQualifiedIdType((ObjCProtocolDecl**)PQ,
                                              DS.getNumProtocolQualifiers());
      break;
    }
      
    // Unspecified typespec defaults to int in C90.  However, the C90 grammar
    // [C90 6.5] only allows a decl-spec if there was *some* type-specifier,
    // type-qualifier, or storage-class-specifier.  If not, emit an extwarn.
    // Note that the one exception to this is function definitions, which are
    // allowed to be completely missing a declspec.  This is handled in the
    // parser already though by it pretending to have seen an 'int' in this
    // case.
    if (getLangOptions().ImplicitInt) {
      // In C89 mode, we only warn if there is a completely missing declspec
      // when one is not allowed.
      if (DS.isEmpty())
        Diag(DS.getSourceRange().getBegin(), diag::warn_missing_declspec)
        << CodeModificationHint::CreateInsertion(DS.getSourceRange().getBegin(),
                                                 "int");
    } else if (!DS.hasTypeSpecifier()) {
      // C99 and C++ require a type specifier.  For example, C99 6.7.2p2 says:
      // "At least one type specifier shall be given in the declaration
      // specifiers in each declaration, and in the specifier-qualifier list in
      // each struct declaration and type name."
      // FIXME: Does Microsoft really have the implicit int extension in C++?
      unsigned DK = getLangOptions().CPlusPlus && !getLangOptions().Microsoft?
          diag::err_missing_type_specifier
        : diag::warn_missing_type_specifier;
      Diag(DS.getSourceRange().getBegin(), DK)
        << CodeModificationHint::CreateInsertion(DS.getSourceRange().getBegin(),
                                                 "int");
    }
      
    // FALL THROUGH.  
  case DeclSpec::TST_int: {
    if (DS.getTypeSpecSign() != DeclSpec::TSS_unsigned) {
      switch (DS.getTypeSpecWidth()) {
      case DeclSpec::TSW_unspecified: Result = Context.IntTy; break;
      case DeclSpec::TSW_short:       Result = Context.ShortTy; break;
      case DeclSpec::TSW_long:        Result = Context.LongTy; break;
      case DeclSpec::TSW_longlong:    Result = Context.LongLongTy; break;
      }
    }