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 "clang/Sema/SemaInternal.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/Initialization.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;
using namespace sema;

ExprResult Sema::ParseObjCStringLiteral(SourceLocation *AtLocs,
                                        Expr **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;
      }

      // Append the string.
      StrBuf += S->getString();

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

    // 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 if (getLangOptions().NoConstantCFStrings) {
    IdentifierInfo *NSIdent=0;
    std::string StringClass(getLangOptions().ObjCConstantStringClass);
    
    if (StringClass.empty())
      NSIdent = &Context.Idents.get("NSConstantString");
    else
      NSIdent = &Context.Idents.get(StringClass);
    
    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 NSConstantString interface defined then treat this
      // as error and recover from it.
      Diag(S->getLocStart(), diag