MiniValgrind

Simple tool for memory leak detection in programs written in simple C-like language (MiniC). Lexer and parser are generated by Flex and Bison. Works on Windows with Cygwin and on Linux.

Paper (in Russian)

Building

Requires gcc, Flex and Bison

$ make

Usage

Run

$ ./MiniValgrind < Tests/test1.txt

Output

If there are memory leaks in your program, you will see warning like this:

Memory leaks: 1 blocks, total size = 10 int

If there are syntax errors in your program, you will see error like this:

syntax error, line 2

If there are runtime errors, you will see error like this:

Error:    Invalid value's type
Aborted.

Testing

You can run unit test:

$ python Tests/UnitTest.py

or memory test of MiniValgrind (requires original Valgrind)

$ python Test/MemoryTest.py

MiniC overview

MiniC program is enclosed between#begin and #end. All MiniC programs must have a main() function — entry point of the program.

Data types

There are three data types in MiniC: integer (int), pointer to integer (ptr) and array of integer (arr):

int x;
int y = 15;
ptr p = &x; // now *p == 15

ptr can be used as reference to array:

arr a[2];
a[0] = 1;
a[1] = 2;
ptr p = a; // now p[0] == 1, p[1] == 2
p[0] = 5;  // now p[0] == a[0] == 5

Operators and statements

Arithmetic (+, -, *, /, %, ++, --), logical (!, &&, ||) and comparison operators (<, <=, ==, >=, >, !=) are similar to C.

Statements: if, for, while, return:

if (x == y) {
    while (x < 10) {
        z++;
    }
else {
    for (int i = 0; i < 5; i++;) { // yes, there is a semicolon after i++
        print(i);
    }
}

Functions

MiniC has two manual memory management functions: malloc and free (similar to C):

ptr p = malloc(10); // now it has p[0], ..., p[9]
free(p); // delete p[0], ..., p[9]

Also MiniC has print function:

int x = 10;
int y = 5;
print(2 * x + y + 7); // "32"

You can define your own functions (return type may be int, ptr or arr):

int swap(ptr p, ptr q) {
    int tmp = *p;
    *p = *q;
    *q = tmp;
    return 0;
}

Global variables

You can define global variables by using inside your program (i.e. between #begin and #end, out of any function):

#begin
global {
    int x = 3;
    int y = 4;
}

int main() {
    y++;
    print(y); // "5"
    return 0;
}
#end