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39af5d020e
Adds timing support to Verilator. It makes it possible to use delays,
event controls within processes (not just at the start), wait
statements, and forks.
Building a design with those constructs requires a compiler that
supports C++20 coroutines (GCC 10, Clang 5).
The basic idea is to have processes and tasks with delays/event controls
implemented as C++20 coroutines. This allows us to suspend and resume
them at any time.
There are five main runtime classes responsible for managing suspended
coroutines:
* `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle`
with move semantics and automatic cleanup.
* `VlDelayScheduler`, for coroutines suspended by delays. It resumes
them at a proper simulation time.
* `VlTriggerScheduler`, for coroutines suspended by event controls. It
resumes them if its corresponding trigger was set.
* `VlForkSync`, used for syncing `fork..join` and `fork..join_any`
blocks.
* `VlCoroutine`, the return type of all verilated coroutines. It allows
for suspending a stack of coroutines (normally, C++ coroutines are
stackless).
There is a new visitor in `V3Timing.cpp` which:
* scales delays according to the timescale,
* simplifies intra-assignment timing controls and net delays into
regular timing controls and assignments,
* simplifies wait statements into loops with event controls,
* marks processes and tasks with timing controls in them as
suspendable,
* creates delay, trigger scheduler, and fork sync variables,
* transforms timing controls and fork joins into C++ awaits
There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`)
that integrate static scheduling with timing. This involves providing
external domains for variables, so that the necessary combinational
logic gets triggered after coroutine resumption, as well as statements
that need to be injected into the design eval function to perform this
resumption at the correct time.
There is also a function that transforms forked processes into separate
functions.
See the comments in `verilated_timing.h`, `verilated_timing.cpp`,
`V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals
documentation for more details.
Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
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| .. | ||
| build.sh | ||
| Dockerfile | ||
| README.rst | ||
Verilator Build Docker Container
================================
This Verilator Build Docker Container is set up to compile and test a
Verilator build. It uses the following parameters:
- Source repository (default: https://github.com/verilator/verilator)
- Source revision (default: master)
- Compiler (GCC 10.3.0, clang 10.0.0, default: 10.3.0)
The container is published as ``verilator/verilator-buildenv`` on `docker
hub
<https://hub.docker.com/repository/docker/verilator/verilator-buildenv>`__.
To run the basic build using the current Verilator master:
::
docker run -ti verilator/verilator-buildenv
To also run tests:
::
docker run -ti verilator/verilator-buildenv test
To change the compiler:
::
docker run -ti -e CC=clang-10 -e CXX=clang++-10 verilator/verilator-buildenv test
The tests that involve gdb are not working due to security restrictions.
To run those too:
::
docker run -ti -e CC=clang-10 -e CXX=clang++-10 --cap-add=SYS_PTRACE --security-opt seccomp=unconfined verilator/verilator-buildenv test
Rather then building using a remote git repository you may prefer to use a
working copy on the local filesystem. Mount the local working copy path as
a volume and use that in place of git. When doing this be careful to have
all changes committed to the local git area. To build the current HEAD from
top of a repository:
::
docker run -ti -v ${PWD}:/tmp/repo -e REPO=/tmp/repo -e REV=`git rev-parse --short HEAD` --cap-add=SYS_PTRACE --security-opt seccomp=unconfined verilator/verilator-buildenv test
Rebuilding
----------
To rebuild the Verilator-buildenv docker image, run:
::
docker build .
This will also build SystemC under all supported compiler variants to
reduce the SystemC testing time.