path: root/lib/Sema/SemaChecking.cpp

//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements extra semantic analysis beyond what is enforced 
//  by the C type system.
//
//===----------------------------------------------------------------------===//

#include "Sema.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/LiteralSupport.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "SemaUtil.h"
using namespace clang;

/// CheckFunctionCall - Check a direct function call for various correctness
/// and safety properties not strictly enforced by the C type system.
Action::ExprResult
Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCallRaw) {
  llvm::OwningPtr<CallExpr> TheCall(TheCallRaw);
  // Get the IdentifierInfo* for the called function.
  IdentifierInfo *FnInfo = FDecl->getIdentifier();
  
  switch (FnInfo->getBuiltinID()) {
  case Builtin::BI__builtin___CFStringMakeConstantString:
    assert(TheCall->getNumArgs() == 1 &&
           "Wrong # arguments to builtin CFStringMakeConstantString");
    if (CheckBuiltinCFStringArgument(TheCall->getArg(0)))
      return true;
    return TheCall.take();
  case Builtin::BI__builtin_va_start:
    if (SemaBuiltinVAStart(TheCall.get())) {
      return true;
    }
    return TheCall.take();
  case Builtin::BI__builtin_isgreater:
  case Builtin::BI__builtin_isgreaterequal:
  case Builtin::BI__builtin_isless:
  case Builtin::BI__builtin_islessequal:
  case Builtin::BI__builtin_islessgreater:
  case Builtin::BI__builtin_isunordered:
    if (SemaBuiltinUnorderedCompare(TheCall.get()))
      return true;
    return TheCall.take();
  case Builtin::BI__builtin_return_address:
  case Builtin::BI__builtin_frame_address:
    if (SemaBuiltinStackAddress(TheCall.get()))
      return true;
    return TheCall.take();
  case Builtin::BI__builtin_shufflevector:
    return SemaBuiltinShuffleVector(TheCall.get());
  }
  
  // Search the KnownFunctionIDs for the identifier.
  unsigned i = 0, e = id_num_known_functions;
  for (; i != e; ++i) { if (KnownFunctionIDs[i] == FnInfo) break; }
  if (i == e) return TheCall.take();
  
  // Printf checking.
  if (i <= id_vprintf) {
    // Retrieve the index of the format string parameter and determine
    // if the function is passed a va_arg argument.
    unsigned format_idx = 0;
    bool HasVAListArg = false;
    
    switch (i) {
    default: assert(false && "No format string argument index.");
    case id_printf:    format_idx = 0; break;
    case id_fprintf:   format_idx = 1; break;
    case id_sprintf:   format_idx = 1; break;
    case id_snprintf:  format_idx = 2; break;
    case id_asprintf:  format_idx = 1; break;
    case id_NSLog:     format_idx = 0; break;
    case id_vsnprintf: format_idx = 2; HasVAListArg = true; break;
    case id_vasprintf: format_idx = 1; HasVAListArg = true; break;
    case id_vfprintf:  format_idx = 1; HasVAListArg = true; break;
    case id_vsprintf:  format_idx = 1; HasVAListArg = true; break;
    case id_vprintf:   format_idx = 0; HasVAListArg = true; break;
    }
    
    CheckPrintfArguments(TheCall.get(), HasVAListArg, format_idx);       
  }
  
  return TheCall.take();
}

/// CheckBuiltinCFStringArgument - Checks that the argument to the builtin
/// CFString constructor is correct
bool Sema::CheckBuiltinCFStringArgument(Expr* Arg) {
  Arg = Arg->IgnoreParenCasts();
  
  StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);

  if (!Literal || Literal->isWide()) {
    Diag(Arg->getLocStart(),
         diag::err_cfstring_literal_not_string_constant,
         Arg->getSourceRange());
    return true;
  }
  
  const char *Data = Literal->getStrData();
  unsigned Length = Literal->getByteLength();
  
  for (unsigned i = 0; i < Length; ++i) {
    if (!isascii(Data[i])) {
      Diag(PP.AdvanceToTokenCharacter(Arg->getLocStart(), i + 1),
           diag::warn_cfstring_literal_contains_non_ascii_character,
           Arg->getSourceRange());
      break;
    }
    
    if (!Data[i]) {
      Diag(PP.AdvanceToTokenCharacter(Arg->getLocStart(), i + 1),
           diag::warn_cfstring_literal_contains_nul_character,
           Arg->getSourceRange());