add your own instructions using pin

Question

Is it possible to add your own code in the code generated by intel-pin?

I was wondering this for a while, I created a simple tool:

#include <fstream>
#include <iostream>
#include "pin.H"

// Additional library calls go here

/*********************/

// Output file object
ofstream OutFile;

//static uint64_t counter = 0;

uint32_t lock = 0;
uint32_t unlock = 1;
std::string rtin = "";
// Make this lock if you want to print from _start
uint32_t key = unlock;

void printmaindisas(uint64_t addr, std::string disassins)
{
    std::stringstream tempstream;
    tempstream << std::hex << addr;
    std::string address = tempstream.str();
    if (key)
        return;
    if (addr > 0x700000000000)
        return;
    std::cout<<address<<"\t"<<disassins<<std::endl;
}

void mutex_lock()
{

key = !lock;
std::cout<<"out\n";

}
void mutex_unlock()
{

    key = lock;
    std::cout<<"in\n";

}

void Instruction(INS ins, VOID *v)
{
    //if
  // Insert a call to docount before every instruction, no arguments are passed
  INS_InsertCall(ins, IPOINT_BEFORE, (AFUNPTR)printmaindisas, IARG_ADDRINT, INS_Address(ins),
  IARG_PTR, new string(INS_Disassemble(ins)), IARG_END);
    //std::cout<<INS_Disassemble(ins)<<std::endl;
}

void Routine(RTN rtn, VOID *V)
{
    if (RTN_Name(rtn) == "main")
    {
        //std::cout<<"Loading: "<<RTN_Name(rtn) << endl;
        RTN_Open(rtn);
        RTN_InsertCall(rtn, IPOINT_BEFORE, (AFUNPTR)mutex_unlock, IARG_END);
        RTN_InsertCall(rtn, IPOINT_AFTER, (AFUNPTR)mutex_lock, IARG_END);
        RTN_Close(rtn);
    }
}

KNOB<string> KnobOutputFile(KNOB_MODE_WRITEONCE, "pintool", "o", "mytool.out", "specify output file name");
/*
VOID Fini(INT32 code, VOID *v)
{
    // Write to a file since cout and cerr maybe closed by the application
    OutFile.setf(ios::showbase);
    OutFile << "Count " << count << endl;
    OutFile.close();
}
*/

int32_t Usage()
{
  cerr << "This is my custom tool" << endl;
  cerr << endl << KNOB_BASE::StringKnobSummary() << endl;
  return -1;
}

int main(int argc, char * argv[])
{
  // It must be called for image instrumentation
  // Initialize the symbol table
  PIN_InitSymbols();

  // Initialize pin
  if (PIN_Init(argc, argv)) return Usage();
  // Open the output file to write
  OutFile.open(KnobOutputFile.Value().c_str());

  // Set instruction format as intel
    // Not needed because my machine is intel
  //PIN_SetSyntaxIntel();

  RTN_AddInstrumentFunction(Routine, 0);
  //IMG_AddInstrumentFunction(Image, 0);

  // Add an isntruction instrumentation
  INS_AddInstrumentFunction(Instruction, 0);

  //PIN_AddFiniFunction(Fini, 0);

  // Start the program here
  PIN_StartProgram();

  return 0;

}

If I print the following c code (which does literally nothing):

int main(void)
{}

Gives me this output:

in
400496  push rbp
400497  mov rbp, rsp
40049a  mov eax, 0x0
40049f  pop rbp
out

And with the following code:

#include <stdio.h>
int main(void)
{
  printf("%s\n", "Hello");
}

prints:

in
4004e6  push rbp
4004e7  mov rbp, rsp
4004ea  mov edi, 0x400580
4004ef  call 0x4003f0
4003f0  jmp qword ptr [rip+0x200c22]
4003f6  push 0x0
4003fb  jmp 0x4003e0
4003e0  push qword ptr [rip+0x200c22]
4003e6  jmp qword ptr [rip+0x200c24]
Hello
4004f4  mov eax, 0x0
4004f9  pop rbp
out

So, my question is, is it possible to add:

4004ea  mov edi, 0x400580
4004ef  call 0x4003f0
4003f0  jmp qword ptr [rip+0x200c22]
4003f6  push 0x0
4003fb  jmp 0x4003e0
4003e0  push qword ptr [rip+0x200c22]
4003e6  jmp qword ptr [rip+0x200c24]

instructions in my first code (code with no print function), using pin in the instrumentation routine/ or analysis routine, so that I can imitate the my second code (by dynamically adding those instructions)? (I don't want to call printf directly, but want to imitate the behavior) (in future I was thinking of imitating sanity checker or intel mpx using pin, if I could add these check instructions dynamically in some way)

I looked at pin documentation, it has the instruction modification api, but it can be only used to add direct/ indirect branches or delete instructions (but we can't add add new ones).