Question

我正在使用C ++创建一个虚拟机，一切都在OSX上运行良好，但是当我在Windows上测试它时编译很好，没有错误或警告，但程序在我尝试为索引赋值时保持崩溃在数组中。我没有使用任何外部库或任何东西，所以我不知道它为什么会一直崩溃。

THE LINE WHERE IT CRASHES:
instarray[i] = value;

下面我还提供了整个文件来帮助您调试它。

#include <iostream>
#include <string>
#include <fstream>
#include <sstream>
#include <algorithm>

#define OP_EOI 0
#define OP_EOP 1
#define OP_PUSH 2
#define OP_POP 3
#define OP_PRINT 4
#define OP_ADD 5
#define OP_MUL 6
#define OP_SUB 7

using namespace std;

class reedoovm {

    private:
        string filedata;
        string instruction;
        string file;
        int instr;
        int instructionCount;
        int instructionPointer;
        int stack;

    public:
        string load_program(string filename) {
            ifstream rdfile(filename);
            while(rdfile >> instruction) {          /* Get each instruction */
                    filedata += instruction;        /* Append the instruction to filedata */
                    filedata += ",";                /* Append a comma to separate each instruction */
                }
            rdfile.close();                         /* Close the file */
            return filedata;                        /* Return the filedata */
        }

        int *instrToArr(string file) {
            stringstream hextoint;
            unsigned int value;
            string s = file;                        /* store fconv in a variable "s" */
            string delimiter = ",";                 /* The delimiter */
            size_t pos = 0;
            string token;
            int i = 0;
            int inst;
            static int* instarray;
            cout << "works" << endl;
            //instarray = (int*) calloc(instructionCount,sizeof(int));
            instarray = (int *) malloc(instructionCount*sizeof(int));
           // instarray[10];
            instructionCount = count(file.begin(), file.end(), ',');
            while ((pos = s.find(delimiter)) != string::npos) {     /* Convert hex instructions to decimal */
               cout << "works" << endl;
                token = s.substr(0, pos);
                cout << token << endl;
                stringstream hextoint(token);
                hextoint >> hex >> value;
                cout << value << endl;
                if (i < instructionCount) {
                    instarray[i] = value;
                    i++;
                    cout << "works" << endl;
                }
                cout << i << endl;
                s.erase(0, pos + delimiter.length());
            }
            return instarray;
        }

        int * instructionArray(int instructionArray[]) {
            return instructionArray;
        }

        int getNextIntruction(int instructions[], int i) {
            return instructions[i];
        }

        void do_PRINT() {

        }

        void do_PUSH(int instructions, int i) {
            //cout << instructions[i + 1] << endl;
        }

        void run_program(int instructions[], string file) {
            int loop = 1;
            int i = 0;
            string delimiter = ",";                 /* The delimiter */
            size_t pos = 0;
            string token;
            int iterator = 0;
            instructionCount = count(file.begin(), file.end(), ',');
            int instructionOrLiteralArray[instructionCount];
            while ((pos = file.find(delimiter)) != string::npos) {     /* Convert hex instructions to decimal */
                token = file.substr(0, pos);
                if (token.length() == 2) {                             /* Operation */
                    instructionOrLiteralArray[iterator] = 0;
                } else {
                    instructionOrLiteralArray[iterator] = 1;           /* Literal */
                }
                iterator++;
                 file.erase(0, pos + delimiter.length());
            }
            while (loop) {

                instr = getNextIntruction(instructions, i);

                if (instr == OP_EOI && instructionOrLiteralArray[i] == 0) {
                    cout << "EOI" << endl;
                } else if (instr == OP_EOI && instructionOrLiteralArray[i] == 1) {
                    cout << "Literal" << endl;
                }

                if (instr == OP_PUSH && instructionOrLiteralArray[i] == 0) {
                    do_PUSH(instr, i);
                } else if (instr == OP_PUSH && instructionOrLiteralArray[i] == 1) {
                    cout << "Literal" << endl;
                }

                if (instr == OP_PRINT && instructionOrLiteralArray[i] == 0) {
                    do_PRINT();
                } else if (instr == OP_PRINT && instructionOrLiteralArray[i] == 1) {
                    cout << "Literal" << endl;
                }

                if (instr == OP_POP && instructionOrLiteralArray[i] == 0) {
                    cout << "POP" << endl;
                } else if (instr == OP_POP && instructionOrLiteralArray[i] == 1) {
                    cout << "Literal" << endl;
                }

                if (instr == OP_ADD && instructionOrLiteralArray[i] == 0) {
                    cout << "ADD" << endl;
                } else if (instr == OP_ADD && instructionOrLiteralArray[i] == 1) {
                    cout << "Literal" << endl;
                }

                if (instr == OP_SUB && instructionOrLiteralArray[i] == 0) {
                    cout << "MUL" << endl;
                } else if (instr == OP_MUL && instructionOrLiteralArray[i] == 1) {
                    cout << "Literal" << endl;
                }

                else if (instructionOrLiteralArray[i] == 1) {
                    cout << "Literal" << endl;
                }

                if (i < instructionCount) {
                    i++;
                } else {
                    loop = 0;
                }
            }
        }

        void execute_program(string s) {
            file = load_program(s);
            int * arr = instrToArr(file);
            int * instructions = instructionArray(arr);
            run_program(instructions, file);
        }       

};

int main(int argc, char* argv[]) {
    reedoovm rd;
    rd.execute_program(argv[1]);
    return 0;
}

我一直盯着代码看了一个多小时，我似乎无法找到问题。

Answer 1

该函数具有未定义的行为

     instarray = (int *) malloc(instructionCount*sizeof(int));
     // instarray[10];
     instructionCount = count(file.begin(), file.end(), ',');

您正在使用未初始化的变量instructionCount，或者至少我找不到在分配内存的语句中初始化它的代码。只有在那之后你才能分配变量。

另请注意，您应该在C ++中使用operator new而不是malloc。

Answer 2

这通常意味着你超越了数组的末尾，并且它导致了分段错误。请记住，数组是0索引的（例如，如果数组有3个元素，则有效索引值的范围为0到2）。看起来你在代码中占了这个，但是你仍然以某种方式超出了数组的范围。我会添加一个检查以确保instructionCount不大于sizeof（instarray） - 1，并且它大于0.您可以使用调试器和/或cout语句，查看这些变量的值以查看是什么出错了。

C ++ Windows在数组崩溃程序中设置值

2 个答案: