VPP provides the I/S for developing custom plugins that can be hooked into a graph of nodes. I've only seen examples for such plugins written in the C language, and was wondering whether other language, Go for instance, can also be used to write such plugins.
I have no idea what "VPP" is but nonetheless the answer is: "maybe"; here's why:
Go code is able to interface with C libraries via its facility known as cgo.
cgo is a multiple-faceted thing: it allows you to "export" certain Go functions in a certain way so that they can be called from the C side, and it allows you to call functions from the C side. It also allows you to write bits of inline C code to provide glue for the C side, when necessary.
Since some time Go building toolset (at least its "reference" implementation) provides for compiling Go code into a static or dynamic library with C-compatible API.
See this.
With these things in mind, in theory, it should be possible to do what you're after.
Note some possible obstacles:
Most of the time, if a "platform" allows you to write a "plugin" in C, it presupposes your plugin will make extensive use of the platform's own API.
This usually means your plugin is supposed to include certain header files provided by the platform.
The platform might also require your plugin to link against some platform-provided library (usually shared), or libraries.
cgo can do all of the above, but you will need to scrutinize the API provided by the platform and maybe write Go helpers to make its usage more natural for the Go code.
Building/linking issues (usually the locations of the header files and the libs) may also be a thing to solve.
Related
It's trivial to call c from rust normally, is there a way to do so from a substrate project? I can't find anything online saying it's possible or it's not possible.
I have a c library I'd like to use as part of a substrate project and I was wondering if it would be possible to use it without rewriting it.
Many FFI libraries are no_std compliant, this is the only hard requirement for being used in substrate runtimes. Checkout the list here and look for that tag for options to move forward:
https://lib.rs/development-tools/ffi
If you are using this library outside the runtime, you should be able to use any rust library.
I am trying to understand the multiarch Makefile based build system found in opensource projects such as linux kernel, glibc and so on. In all of these projects the source code is organized as C/C++ modules(e.g. filesystem, networking, logging) etc, generic headers such as include/ and then arch specific directory tree (arch/{x86,mips,arm}) etc. I want to understand how to layout of such projects is formed what specific language constructs and techniques are used to map the highlevel C routines to their arch specific implementations. I had tried to look around on the internet and didn't find information covering exactly this subject or introducing how to layout and design the Makefiles, organize C and assembly so that the build system correctly creates the build.
For a concrete example, lets consider the glibc, which utilizes a macro HP_TIMING_NOW whose implementation differs for different architectures (x86_64, powerpc...).
I do understand that the whole build system works through invoking make recursively but may understanding of this process is superficial and I am looking for some concrete explanation in the form of resources or answers to cover this subject.
Thanks in advance
https://webassembly.studio/ allows inspection of WebAssembly (WASM) files and the corresponding SpiderMonkey-generated x86 code. I'd like to similarly inspect instructions generated by V8's WASM compilers (Liftoff and TurboFan).
I'm entirely unfamiliar with V8's codebase/API (I compiled & linked it and followed some tutorials, though). There seems to be a v8::CompiledWasmModule class available, but it does not seem to expose access to generated x86/x64 instructions by either Liftoff or TurboFan.
WebAssembly - adding a new opcode describes the process of adding a WASM opcode to V8. Seemingly appropriate functions for WASM compilation/execution are available in the mentioned classes. Though, these seem rather deeply layered within the V8 codebase and would be difficult to access were I to link V8 as a library. Also, I'm unsure if this corresponds to Liftoff or TurboFan.
Could anybody familiar with the V8 codebase give me some pointers as to how I can access Liftoff and/or TurboFan's WebAssembly compilation module, as to obtain x86/x64 code?
To inspect generated code, you can run the d8 shell with the --print-wasm-code flag. You'll need either a debug build, or a release build with the v8_enable_disassembler = true GN arg.
There's no existing way to retrieve generated code via V8's API; so if that's what you want, then you'd have to add it. Keep in mind that V8 is not designed to be a standalone compiler, which means generated code assumes that it's going to run "inside V8", so if you wanted to use it for anything else, you'd have to make significant modifications.
What is the Go language compiled to? Nobody seems to want to write it anywhere on the net. I am searching for the target language. I am thinking it's probably assembly, C, or relocatable machine code?
The reference implementation compiles Go to native machine code. The code is generated to be not relocateable.
The language has been designed to allow other target platforms as well. For instance, there are implementations that compile Go code into Javascript and PHP.
It is not possible to use Go code in a shared library.
In Java when you compile a .java file which defines a class, it creates a .class file. If you provide these class files to your coworkers then they cannot modify your source. You can also bundle all of these class files into a jar file to package it up more neatly and distribute it as a single library.
Does Ruby have any features like these when you want to share your functionality with your coworkers but you don't want them to be able to modify the source (unless they ask you for the actual .rb source file and tell you that they want to change it)?
I believe the feature you are looking for is called "trust" (and a source code control repository). Ruby isn't compiled in the same way that Java is, so no you can't do this.
I have to say your are in a rough position, not wanting to share code with a coworker. However, given that this is an unassailable constraint perhaps you could change the nature of the problem.
If you have a coworker that needs access to some service provided by a library of yours, perhaps you could expose it by providing a web/rest service instead of as a .rb file.
This way you can hide your code behind a web server, and if there is a network architecture that allows for low latency making these service calls, you can effectively achive the same goal.
Trust is a lot easier though.
edit:
Just saw this on HN: http://blog.astrails.com/2009/5/12/ruby-http-require, allows a ruby file to include another file through http instead of the filesystem.
Ruby is
A dynamic, interpreted, open source programming language with a focus on simplicity and productivity.
So like all interpreted languages, you need to give the source code to anyone who want's to execute your program/script.
By the way searching "compiled ruby" on google returned quiet a few results.
I don't think there is one. Ruby is purely an interpreted language, which means ruby interprets your source code directly in order to run it. Java is compiled, so there's an intermediate bytecode (the .class). You can obfuscate your ruby if you really wish, but it's probably more trouble than it's worth.
Just to make sure you realize, however, upwards of 95% of Java can be decompiled back into source using various free utilities, so in reality, Java's compilation isn't much better than distributing Ruby source.
This is not a language specific problem and one that can be managed more effectively through source control software.
There is a library called ruby2c that compiles a subset of Ruby into C code (which you can then compile into native code, if you want).
It was actually originally written as a Ruby code obfuscator (but has since been used for lots of other stuff, including Ruby Arduino development).