path: root/lib/Sema/SemaExprObjC.cpp

//===--- SemaExprObjC.cpp - Semantic Analysis for ObjC Expressions --------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements semantic analysis for Objective-C expressions.
//
//===----------------------------------------------------------------------===//

#include "Sema.h"
#include "Lookup.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/TypeLoc.h"
#include "llvm/ADT/SmallString.h"
#include "clang/Lex/Preprocessor.h"

using namespace clang;

Sema::ExprResult Sema::ParseObjCStringLiteral(SourceLocation *AtLocs,
                                              ExprTy **strings,
                                              unsigned NumStrings) {
  StringLiteral **Strings = reinterpret_cast<StringLiteral**>(strings);

  // Most ObjC strings are formed out of a single piece.  However, we *can*
  // have strings formed out of multiple @ strings with multiple pptokens in
  // each one, e.g. @"foo" "bar" @"baz" "qux"   which need to be turned into one
  // StringLiteral for ObjCStringLiteral to hold onto.
  StringLiteral *S = Strings[0];

  // If we have a multi-part string, merge it all together.
  if (NumStrings != 1) {
    // Concatenate objc strings.
    llvm::SmallString<128> StrBuf;
    llvm::SmallVector<SourceLocation, 8> StrLocs;

    for (unsigned i = 0; i != NumStrings; ++i) {
      S = Strings[i];

      // ObjC strings can't be wide.
      if (S->isWide()) {
        Diag(S->getLocStart(), diag::err_cfstring_literal_not_string_constant)
          << S->getSourceRange();
        return true;
      }

      // Get the string data.
      StrBuf.append(S->getStrData(), S->getStrData()+S->getByteLength());

      // Get the locations of the string tokens.
      StrLocs.append(S->tokloc_begin(), S->tokloc_end());

      // Free the temporary string.
      S->Destroy(Context);
    }

    // Create the aggregate string with the appropriate content and location
    // information.
    S = StringLiteral::Create(Context, &StrBuf[0], StrBuf.size(), false,
                              Context.getPointerType(Context.CharTy),
                              &StrLocs[0], StrLocs.size());
  }

  // Verify that this composite string is acceptable for ObjC strings.
  if (CheckObjCString(S))
    return true;

  // Initialize the constant string interface lazily. This assumes
  // the NSString interface is seen in this translation unit. Note: We
  // don't use NSConstantString, since the runtime team considers this
  // interface private (even though it appears in the header files).
  QualType Ty = Context.getObjCConstantStringInterface();
  if (!Ty.isNull()) {
    Ty = Context.getObjCObjectPointerType(Ty);
  } else {
    IdentifierInfo *NSIdent = &Context.Idents.get("NSString");
    NamedDecl *IF = LookupSingleName(TUScope, NSIdent, AtLocs[0],
                                     LookupOrdinaryName);
    if (ObjCInterfaceDecl *StrIF = dyn_cast_or_null<ObjCInterfaceDecl>(IF)) {
      Context.setObjCConstantStringInterface(StrIF);
      Ty = Context.getObjCConstantStringInterface();
      Ty = Context.getObjCObjectPointerType(Ty);
    } else {
      // If there is no NSString interface defined then treat constant
      // strings as untyped objects and let the runtime figure it out later.
      Ty = Context.getObjCIdType();
    }
  }

  return new (Context) ObjCStringLiteral(S, Ty, AtLocs[0]);
}

Expr *Sema::BuildObjCEncodeExpression(SourceLocation AtLoc,
                                      TypeSourceInfo *EncodedTypeInfo,
                                      SourceLocation RParenLoc) {
  QualType EncodedType = EncodedTypeInfo->getType();
  QualType StrTy;
  if (EncodedType->isDependentType())
    StrTy = Context.DependentTy;
  else {
    std::string Str;
    Context.getObjCEncodingForType(EncodedType, Str);

    // The type of @encode is the same as the type of the corresponding string,
    // which is an array type.
    StrTy = Context.CharTy;
    // A C++ string literal has a const-qualified element type (C++ 2.13.4p1).
    if (getLangOptions().CPlusPlus || getLangOptions().ConstStrings)
      StrTy.addConst();
    StrTy = Context.getConstantArrayType(StrTy, llvm::APInt(32, Str.size()+1),
                                         ArrayType::Normal, 0);
  }

  return new (Context) ObjCEncodeExpr(StrTy, EncodedTypeInfo, AtLoc, RParenLoc);
}

Sema::ExprResult Sema::ParseObjCEncodeExpression(SourceLocation AtLoc,
                                                 SourceLocation EncodeLoc,
                                                 SourceLocation LParenLoc,
                                                 TypeTy *ty,
                                                 SourceLocation RParenLoc) {
  // FIXME: Preserve type source info ?
  TypeSourceInfo *TInfo;
  QualType EncodedType = GetTypeFromParser(ty, &TInfo);
  if (!TInfo)
    TInfo = Context.getTrivialTypeSourceInfo(EncodedType,
                                             PP.getLocForEndOfToken(LParenLoc));

  return BuildObjCEncodeExpression(AtLoc, TInfo, RParenLoc);
}

Sema::ExprResult Sema::ParseObjCSelectorExpression(Selector Sel,
                                                   SourceLocation AtLoc,