eriknyquist / lintern

lintern

Python-based tool which uses libclang to rewrite C code to fix certain things that static analysis checkers often complain about. Not particularly fancy, just takes care of some of the more mindless things that are annoying for humans to waste their time on, that's all.

You should probably use clang-tidy instead.

Source code formatting / whitespace

Lintern makes a reasonable effort to indent new lines in a way consistent with surrounding lines, however there are not really any features for controlling whitespace. Lintern is all about modifying the stream of tokens, and doesn't really care much about whitespace.

If you need to enforce a certain coding/whitespace style, it is recommended to run lintern first, and then run a tool focused on whitespace (such as clang-format) as a final step.

Configuration file

By default, all rewrite rules are enabled. If you want more control over which rules are enabled, you can write a configuration file. A good starting point is to run python -m lintern -g, which will print configuration file data with all available options enabled. You can save this output to a text file, and use it as your configuration file once you have changed your desired options.

Lintern will look for a configuration file called .lintern. Alternatively, you can pass a different config file using the -f option, e.g. python -m lintern -f other_config_file.txt.

Configuration file options

BracesAroundCodeBlocks

This rule rewrites code blocks following if/else, for, while and do/while statements, ensuring that they are surrounded by braces.

For example:

if (check1())
   func1();
else if (check2())
    if (check3())
        func2();

Becomes:

if (check1())
{
   func1();
}
else if (check2())
{
    if (check3())
    {
        func2();
    }
}

PrototypeFunctionDeclarations

This rule rewrites function declarations and implementations with no function parameters, to ensure 'void' is used in place of function parameters.

For example:

void function();

void function()
{
    return;
}

Becomes:

void function(void);

void function(void)
{
    return;
}

OneDeclarationPerLine

This rule rewrites lines that declare & initialize multiple values in a single statement, to separate each declaration + initialization on its own line and statement.

For example:

static const int a = 2, *b = NULL, **c = NULL;

Becomes:

static const int a = 2;
static const int *b = NULL;
static const int **c = NULL;

InitializeCanonicals

This rule rewrites declarations of canonical data types that have no initial value, and adds a sane initial value.

For example:

volatile float x, *X;
static const bool y;
short *z;

Becomes:

volatile float x = 0.0f, *X = NULL;
static const bool y = false;
short *z = NULL;

TerminateElseIfWithElse

Rewrites else-if chains to ensure they are terminated with an 'else' clause.

For example:

if (check1())
{
    func1();
}
else if (check2())
{
    func2();
}

Becomes:

if (check1())
{
    func1();
}
else if (check2())
{
    func2();
}
else
{
    ;
}

ExplicitUnusedFunctionParams

This rule rewrites function implementations to explicitly mark unused function parameters with "void".

For example:

int func(int a, int b)
{
    return b + 2;
}

Becomes:

int func(int a, int b)
{
    (void) a;

    return b + 2;
}