CODEWITHSUNDEEP
c++segmentation-faultclangllvm
lekso borashvili
lekso borashvili

Reputation: 65

Segmentation fault for calling base class variable

I have been using this code for a long time now in a project. However, I have recently added llvm-config --cxxflags --libs to the compiler in order to link with llvm libraries and it started generating seg faults. I have located the error and it happens when I call base class's variables.

Here is a small example of what I a doing in Literals.hh

class LiteralObj : public RuleObj {

public:

  LiteralObj();
  LiteralObj(char *str);
  ~LiteralObj();
  std::string raw_value;

  static int literalobj_cnt;
  int literalobj_id;
};

class LiteralIntObj : public LiteralObj{

public:

  LiteralIntObj();
  LiteralIntObj(char *str);
  ~LiteralIntObj();
  
  void graphVis(std::ofstream &ofs, std::string &srcRef);

  CODE_GENERATION;
  
  int value;
};

Literals.cc

LiteralObj::LiteralObj() : RuleObj(){
  ENTER_STATEMENT

    raw_value = "";

    literalobj_id = literalobj_cnt;
    literalobj_cnt++;

}

LiteralObj::LiteralObj(char *str) : RuleObj(){
    ENTER_STATEMENT
    std::cerr << ruleobj_id << "\n";
    raw_value     = str;
    literalobj_id = literalobj_cnt;
    literalobj_cnt++;
}

LiteralObj::~LiteralObj()
{
  ENTER_STATEMENT;
}

LiteralIntObj::LiteralIntObj() : LiteralObj()
{
   ENTER_STATEMENT;
   value = 0;               
}
LiteralIntObj::LiteralIntObj(char *str) : LiteralObj(str)
{ 
  
  ENTER_STATEMENT; 
  std::cerr << ruleobj_id << '\n';
  value = stoi(raw_value);
}

LiteralIntObj::~LiteralIntObj()
{
  ENTER_STATEMENT;
}

void LiteralIntObj::graphVis(std::ofstream &ofs, std::string &srcRef) {
  ENTER_GRAPHVIS;

  // -- define names
  std::string currRef  = "LiteralIntObj";
  std::string name     = "LiteralInt";

  std::cerr << raw_value << "\n";
  //it crashes here with SEGFAULT.

}

The code prints out raw_value of the base class fine for the first object, but, when the second is called SEGMENTATION Fault is generated.

Upvotes: 2

Views: 97

Answers (1)

lekso borashvili
lekso borashvili

Reputation: 65

When i changed compile options the pointers were set to 0xfffffff by default instead of 0. Therefore the check if (pointer) generated true even when the pointer were not initialized that led to calling function graphViz().

Upvotes: 2

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