# The Calyx Compiler

The source code documentation for the compiler can be [found here][comp].

The Calyx compiler has several command line to control the execution of various
passes and backends.

## Specifying Primitives Library

The compiler implementation uses a standard library of components to compile
programs.

The only standard library for the compiler is located in:
```
<path to Calyx repository>/primitives
```

Specify the location of the library using the `-l` flag:
```
cargo run -- -l ./primitives
```

## Primitive Libraries Format
The primitive libraries consist of a `.futil` file paired with a `.sv` file. The
`.futil` file defines a series of Calyx shim bindings in `extern` blocks which
match up with SystemVerilog definitions of those primitives. These libraries may
also expose components written in Calyx, usually defined using primitives
exposed by the file.

No Calyx program can work without the primitives defined in the [Core Library](libraries/core.md).

## Controlling Passes

The compiler is organized as a sequence of passes that are run when the compiler
executes.

To get a complete list of all passes, run the following from the repository
root:

```
cargo run -- --list-passes
```

This generates results of the form:

```
Passes:
- collapse-control
- compile-control
...

Aliases:
- all: well-formed, papercut, remove-external-memories, ...
...
```

The first section list all the passes implemented in the compiler.
The second section lists *aliases* for combination of passes that are commonly
run together.
For example, the alias `all` is an ordered sequence of default passes executed
when the compiler is run from the command-line.

The command-line provides two options to control the execution of passes:
- `-p, --pass`: Execute this pass or alias. Overrides default alias.
- `-d, --disable-pass`: Disable this pass or alias. Takes priority over `-p`.

For example, we can run the following to disable the `static-timing` pass from
the default execution alias `all`:

```bash
cargo run -- examples/futil/simple.futil -p all -d static-timing
```

[comp]: https://capra.cs.cornell.edu/docs/calyx/source/calyx/