Blech is a language for developing reactive, real-time critical embedded software. This open source project implements a compiler which translates Blech to C. More information can be found on the new homepage.
The software is not ready for production use. It has neither been developed nor tested for a specific use case. However, the license conditions of the applicable Open Source licenses allow you to adapt the software to your needs. Before using it in a safety relevant setting, make sure that the software fulfills your requirements and adjust it according to any applicable safety standards (e.g. ISO 26262).
Quick guide to the Blech compiler
Build the Blech to C compiler blechc
Clone the project using
git clone https://github.com/boschresearch/blech
To build the project, you need
.Net installed. Go to the Microsoft Download .NET page and follow the instructions to install
.Net 5.0 available for your operating system.
Navigate to the folder where you have checked out the Blech project. It should contain the file
Blech.sln. Now you have choices:
For a simple debug build run
./src/blechc/bin/Debug/net5.0/blechc.dll. Use the dotnet command to start the compiler like so
For a release build additionally use the
Finally, for a self-contained release build, which is operating system dependent, you need to run
dotnet publishwith a specific runtime identifier like so
dotnet publish -c Release -r win-x64
For Linux use
linux-x64, for MacOS use
This creates a folder
./src/blechc/bin/Release/net5.0/win-x64/publishwhich contains all files needed for execution. The folder as a whole can be moved arbitrarily. Inside the folder invoke the binary
to run the Blech compiler.
In order to run the unit tests execute
This includes parser, name resolution, type checking and causality checking tests.
If you use VisualStudio 2017 or later, you can open the solution file and build the project from within VisualStudio. You can also run the unit tests provided you have installed the
NUnit3 Test Adapter plugin.
Code generation, however, is tested separately outside this framework. In
dotnet run -- codegeneration tmp
This (upon first invocation) will interactively create a
config file, and then compile every file in
codegeneration to C, compile that to an executable, run it, and compare the resulting trace with the specified trace. In this way we ensure that changes to our backend do not change the behaviour of the generated files.
The batch script
testCodegenerationAll.bat automates this testing process on Windows.
It ensures that the program is executed from the Developer Command Prompt, that generated files from previous runs are deleted and calls the test framework on every folder.
The shell scipt
testCodegnerationAll.sh does the same for MacOS and Linux.
Assuming you have a binary of the Blech Compiler
blechc for your operating system, or you have built the Blech project yourself from sources, this sections tells you how to use it.
blechc binary is in your
$PATH, you can invoke the compiler by simply writing
on the command line interface.
If you do not have a standalone (publish) build and want to use your local Debug (or Release) build, use the
dotnet command to start the compiler from your blech working directory.
From here on out we assume
blechc to be a synonym for either call above
someBlechFile.blcto C code silently. You will only see output on the command line if there are problems with the translation. This will generate a file
blech.cin the same folder which contains a runnable program. It runs in a main loop and calls the entry point activity of
someBlechFile.blc60 times. Furthermore in the subfolder
./blechtwo files are generated
someBlechFile.h. They contain the C code and interface declarations respectively.
Does the same as above but prints out textual representations of intermediate compilation results including: typed syntax tree, control flow graphs and block graphs for activities, C code.
blechc -v d someBlechFile.blc
Run through all compilation phases but do not write any C files. This is useful to check for problems without actually touching anything on the file system.
blechc --dry-run someBlechFile.blc
Compile generated C files
The compiler can generate a test program with trace output using the following options:
blechc --app --trace someBlechFile.c
By default this produces a main program in
blech.c which can be used as a first test. To compile this code you need
to include Blech specific C header files. These are located in
On Windows C compilation may look like this.
mingw32-cc.exe -I. -I<path-to>/blech/src/blechc/include blech.c
Note that the current folder
. is explicitly added as a path to be included.
The resulting executable will run the program for 60 reactions and print the variable evaluations after every reaction in JSON format.
To include the generated C code in your own project inspect
blech.c for details. In particular, make sure you call the
init function on initial startup and then
tick with every reaction.
For programmers familiar with Arduino these correspond to the
The Blech compiler is open-sourced under the Apache-2.0 license. See the LICENSE file for details.
For a list of other open source components included in the Blech compiler, see the file 3rd-party-licenses.txt.