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QUILC
Quilc is an advanced optimizing compiler for the quantum instruction language Quil, licensed under the Apache 2.0 license.
Quilc comprises two projects. The first, cl-quil
, does the heavy
lifting of parsing, compiling, and optimizing Quil code. The second,
quilc
, presents an external interface for using cl-quil
, either using
the binary quilc
application directly, or alternatively by
communicating with an RPCQ server.
Quil is the quantum instruction language, originally developed at Rigetti Computing. In Quil quantum algorithms are expressed using Quil's
standard gates and instructions. One can also use Quil's DEFGATE
to
define new non-standard gates, and DEFCIRCUIT
to build a named circuit
that can be referenced elsewhere in Quil code (analogous to a function
in most other programming languages).
Quil Compiler
This directory contains the quilc
application. quilc
takes as input
arbitrary Quil code, either provided directly to the binary or to the
quilc
server, and produces optimized Quil code. The compiled code is
optimized for the configured instruction set architecture (ISA),
targeting the native gates specified by the ISA.
Cloning the repository
To clone the quilc repository and its bundled submodules, run the following command:
git clone --recurse-submodules https://github.com/quil-lang/quilc.git
Building the Quil Compiler
Prerequisites to building quilc
are:
- Standard UNIX build tools
- SBCL (a recent version, but not SBCL 1.5.6): Common Lisp compiler
- Quicklisp: Common Lisp library manager
- ZeroMQ: Messaging library required by RPCQ. Development headers are required at build time.
Follow these instructions to get started from scratch.
One notorious dependency is MAGICL. It is available on Quicklisp,
but requires you to install some system libraries such as BLAS, LAPACK, and libffi. Follow MAGICL's
instructions carefully before proceeding with loading CL-QUIL or make
ing quilc.
Once these dependencies are installed, building should be easy. Building the quilc
binary is automated using the Makefile
:
$ make quilc
This will create a binary quilc
in the current directory
$ ./quilc --version
To install system-wide issue the command
$ make install
Build flags
quilc
can be built with additional options provided to make
as described below:
Flag | Description |
---|---|
POST_LOAD_ASDF_SYSTEMS | Specify additional ASDF systems to load after quilc as part of the executable. This can be used to build quilc with additional out-of-tree functionality. |
Using the Quil Compiler
The Quil Compiler provides two modes of interaction: (1) communicating
directly with the quilc
binary, providing your Quil code over stdin
;
or (2) communicating with the quilc
server.
quilc
The quilc
binary reads Quil code provided on stdin
:
$ echo H 0 | quilc
$ cat large_file.quil | quilc
Server
For various reasons (e.g. not having to repeatedly load the quilc
binary into memory, communicating over a network) quilc
provides a
an RPCQ server
interface. RPCQ is an open-source
RPC framework developed at Rigetti for efficient network communication
through the QCS stack. The server is started in RPCQ-mode using the
-R
flag
$ quilc -R
+-----------------+
| W E L C O M E |
| T O T H E |
| R I G E T T I |
| Q U I L |
| C O M P I L E R |
+-----------------+
Copyright (c) 2016-2019 Rigetti Computing.
<134>1 2019-01-29T22:03:08Z workstation.local ./quilc 4077 LOG0001 - Launching quilc.
<134>1 2019-01-29T22:03:08Z workstation.local ./quilc 4077 - - Spawning server at (tcp://*:5555) .
The server-mode provides to high-level languages such as Python a way
to communicate with the Quil compiler, thus enabling high-level
abstractions and tools that are not directly available in Quil. The
pyquil
library provides such an interface to quilc
.
CL-QUIL
CL-QUIL
is the Lisp library that implements parsing and compiling
of Quil code. The code can be found under ./src/
. Other lisp libraries, including
quilc
, can depend on it.
Usage
To get up and running quickly using the quilc
Docker image, head directly to the
section "Running the Quil Compiler with Docker" below. Otherwise, the following steps
will walk you through how to build the compiler from source.
Follow the instructions in QVM's
doc/lisp-setup.md to satisfy the
dependencies required to load the CL-QUIL
library. Afterwhich, the
library can be loaded
$ sbcl
* (ql:quickload :cl-quil)
;;; <snip>compilation output</snip>
(:CL-QUIL)
* (cl-quil:parse-quil "H 0")
#<CL-QUIL:PARSED-PROGRAM {100312C643}>
A few good entry points to exploring the library are:
- The functions
cl-quil::parse-quil
insrc/parser.lisp
, andcl-quil:parse-quil
insrc/cl-quil.lisp
and the various transforms therein. - The function
cl-quil:compiler-hook
which constructs a control-flow graph (CFG) and then performs various optimizations on the CFG.
Automated Build, Test, and Release with Docker
The CI pipeline for quilc
produces a Docker image, available at
rigetti/quilc
.
To get the latest stable version of quilc
, run docker pull rigetti/quilc
.
To instead pull a specific version of quilc, run docker pull rigetti/quilc:VERSION
,
where VERSION
is something like 1.10.4
.
The Dockerfile for quilc builds from three parent Docker images:
rigetti/lisp
: Contains SBCL, Quicklisp, and third-party libraries.rigetti/rpcq
: Contains the message spec and RPC framework used by quilc.rigetti/qvm
: Contains the Quantum Virtual Machine, used in the quilc tests.
The Dockerfile for quilc intentionally pins the versions of these three images, which means that the version numbers must be actively incremented as necessary. If the build for quilc is failing, this is probably the place to look, because the unit tests are run inside of a freshly-built quilc Docker image as part of the GitLab CI pipeline.
Running the Quil Compiler with Docker
As outlined above, the Quil Compiler supports two modes of operation: stdin and server.
To run quilc
in stdin mode, do one either of the following:
- The containerized compiler will then read whatever newline-separated Quil instructions you enter, waiting for an EOF signal (Control+d) to compile it.
docker run --rm -it rigetti/quilc
- You can alternatively pipe Quil instructions into the
quilc
container if you drop the-t
.
echo H 0 | docker run --rm -i rigetti/quilc
To run quilc
in server mode, do the following:
docker run --rm -it -p 5555:5555 rigetti/quilc -R
This will spawn an RPCQ-mode quilc
server, that you can communicate with over TCP. If
you would like to change the port of the server to PORT, you can alter the command as follows:
docker run --rm -it -p PORT:PORT rigetti/quilc -R -p PORT
Port 5555 is exposed using the EXPOSE directive in the rigetti/quilc
image, so
you can additionally use the -P
option to automatically bind this container port to a randomly
assigned host port. You can then inspect the mapping using docker port CONTAINER [PORT]
.
Release Process
- Update
VERSION.txt
and push the commit tomaster
. - Push a git tag
vX.Y.Z
that contains the same version number as inVERSION.txt
. - Verify that the resulting build (triggered by pushing the tag) completes successfully.
- Publish a release using the tag as the name.
- Close the milestone associated with this release, and migrate incomplete issues to the next one.
- Update the quilc version of downstream dependencies (if applicable, see next section).
Downstream Dependencies
Currently, there are a couple different components of the Forest SDK that depend on quilc:
It is the responsibility of the releaser to verify that the latest quilc release does not break the test suites of these downstream dependencies. All of these repositories pull the latest released version of quilc as part of their CI pipelines.
Benchmarking
quilc
offers a benchmarking suite to compare its performance against other compilers and
between its own versions. To run the benchmark suite, move to the quilc
root directory,
make sure the git submodules are checked out, and run
make benchmark-qasm
Get involved!
We welcome and encourage community contributions! Peruse our guidelines for contributing to get you up to speed on expectations. Once that's clear, a good place to start is the good first issue section. If you find any bugs, please create an issue.
We look forward to meeting and working with you!
Incompatible software versions
SBCL 1.5.6
There is an issue with
SBCL 1.5.6 that results in unhandled memory faults in
SB-VM::FUNCALLABLE-INSTANCE-TRAMP
when attempting to run quilc
compiled with that version of SBCL. The issue was resolved with SBCL
commit
550c4d2. For
this reason, it's not possible to use quilc or cl-quil with SBCL
1.5.6, but any other recent SBCL version should work fine.