# lookin

**Repository Path**: GalaxyG/lookin

## Basic Information

- **Project Name**: lookin
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2024-08-04
- **Last Updated**: 2024-08-17

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

Lookin
======

## Build from source
Install LLVM:
```
sudo apt install clang-13 llvm-13 llvm-13-dev llvm-13-tools
```
Go to source directory and build with cmake:
```
mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=/path/to/install ..
make
make install
```

## Quick start
Rebuild the source code with compiler tclang:
```
CC=/path/to/install/tclang CXX=/path/to/install/tclang <build command>
```
Then run the application with runtime library:
```
LD_PRELOAD=/path/to/install/liblkinData.so <execution command>
```
For usage, refer to README in example directory.

## Example
Take a look at a simple program of computing greatest common divisor.
```
int gcd(int a, int b)
{
        int r = 1;
        while(r!=0){
            r = a % b;
            a = b;
            b = r;
        }
        return a;
}

int main()
{
        srand((unsigned)time(NULL));
        for (int i=0;i<10;++i) {
                int a = rand()%100;
                int b = rand()%100;
                (void)gcd(a,b);
        }
        return 0;
}
```

Compile directly:
```
cd example
make
```

Run directly and there is no output:
```
./test
```

Then rebuild with lookin:
```
cd example
export CC=/path/to/install/tclang
make
```

And run again:
```
LD_PRELOAD=/path/to/install/liblkinData.so ./test
```
Output is as follows:
```
main
gcd 31 54
gcd_ret 1
gcd 62 5
gcd_ret 1
gcd 99 84
gcd_ret 3
gcd 12 89
gcd_ret 1
gcd 26 80
gcd_ret 2
gcd 22 81
gcd_ret 1
gcd 84 98
gcd_ret 14
gcd 61 13
gcd_ret 1
gcd 41 78
gcd_ret 1
gcd 33 48
gcd_ret 3
main_ret 0
```
Now, each function name and integer arguments are printed.