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/*
 * Verify the memory addressing for BT, BTC, BTR, BTS instructions.
 * This tool expects the specific test code in btc_app.cpp, since it
 * assumes that all of the relevant instructions access a single array.
 */
#include <fstream>
#include <iostream>
#include <iomanip>
#include <stdlib.h>
#include <string.h>

#include "pin.H"

KNOB<string> KnobOutput(KNOB_MODE_WRITEONCE,"pintool", "o", "ea_verifier_bt.out", "Name for log file");

static ofstream out;
static ADDRINT baseAddr = 0;
static int errors = 0;
static int tests  = 0;

static void printHex (ADDRINT p)
{
    UINT32 fieldWidth = (sizeof(ADDRINT) == 4) ? 8 : 12;

    out << std::setw(fieldWidth) << std::hex << p << std::dec ;
}

/************************************************************************/
/* We simply allocate space for the dis-assembled instruction strings and 
 * let them leak.
 */
static char const * formatInstruction(INS ins)
{
    ADDRINT ip = INS_Address(ins);
    string formatted = hexstr(ip) + " " + INS_Disassemble(ins);
    char * res = new char [formatted.length()+1];

    strcpy (res, formatted.c_str());
    
    return res;
}

static int byteOffset(UINT32 size, INT32 bitIndex)
{
    INT32 bitBits = (size == 2) ? 4 : (size == 4) ? 5 : 6;

    return (bitIndex >> bitBits)*size;
}

static VOID ProcessAddress (ADDRINT name, UINT32 size, ADDRINT ea, INT32 bitIndex)
{
    // Work out the base address of the array being accessed
    if (baseAddr == 0)
    {
        baseAddr = ea - byteOffset(size,bitIndex);
        return;
    }

    tests++;
    // Check that the position agrees with what we think it should be.
    if (baseAddr+byteOffset(size,bitIndex) != ea)
    {
        errors++;
        out << (const char *)name << ": Bad EA "; printHex(ea); 
        out << " Expected "; printHex (baseAddr+byteOffset(size,bitIndex));
        out << " Bit offset " << bitIndex << " Access size " << size << endl;
    }
}

static VOID Instrument(INS ins)
{
    UINT32 op = INS_Opcode(ins);

    switch (op)
    {
        case XED_ICLASS_BT:
        case XED_ICLASS_BTC:
        case XED_ICLASS_BTR:
        case XED_ICLASS_BTS:
            // Filter out the BTs we want to look at, we don't expect any in system libraries,
            // but we have seen a bt reg,reg on FC12
            if (INS_IsMemoryRead(ins) && !INS_OperandIsImmediate(ins,1))
                break;
            // Fall through and ignore non mem,reg operations.
        default:
            return;
    }
    
    INS_InsertCall(ins, IPOINT_BEFORE,
                   AFUNPTR(ProcessAddress),
                   IARG_ADDRINT, ADDRINT (formatInstruction(ins)),
                   IARG_MEMORYREAD_SIZE,
                   IARG_MEMORYOP_EA, 0,
                   IARG_REG_VALUE, INS_OperandReg(ins, 1),
                   IARG_END);
}

static BOOL traceFromExecutable(TRACE trace)
{
    RTN rtn = TRACE_Rtn(trace);
    if (!RTN_Valid(rtn))
        return FALSE;
    SEC sec = RTN_Sec(rtn);
    if (!SEC_Valid(sec))
        return FALSE;
    IMG img = SEC_Img(sec);
    if (!IMG_Valid(img))
        return FALSE;
    return IMG_IsMainExecutable(img);
}

VOID Trace(TRACE trace, VOID *v)
{
    // Only instrument the main executable, we're not interested in anything in dynamic libraries.
    if (!traceFromExecutable(trace))
        return;

    for (BBL bbl = TRACE_BblHead(trace); BBL_Valid(bbl); bbl = BBL_Next(bbl))
    {
        for (INS ins = BBL_InsHead(bbl); INS_Valid(ins); ins = INS_Next(ins))
        {
            Instrument(ins);
        }
    }
}

void AtEnd(INT32 code, VOID *arg)
{
    out << "Target exited with code : " << code << endl;
    out << errors << " BTx addressing errors in " << tests << " tests" << endl;
    out.close();
    if (tests == 0)
        exit(-1);
    else
        exit(errors);
}

int main(int argc, char * argv[])
{
    PIN_InitSymbols();
    PIN_Init(argc, argv);

    out.open(KnobOutput.Value().c_str());

    TRACE_AddInstrumentFunction(Trace, 0);
    PIN_AddFiniFunction(AtEnd, 0);

    // Never returns
    PIN_StartProgram();
    
    return 0;
}
