089bbd6588
Previously, `reference_table` mapped from a `Decl` being referenced to the `Decl` that performed the reference. This is convenient for constructing error messages, but problematic for incremental compilation. This is because on an incremental update, we want to efficiently remove all references triggered by an `AnalUnit` which is being re-analyzed. For this reason, `reference_table` now maps the other way: from the `AnalUnit` *performing* the reference, to the `AnalUnit` whose analysis was triggered. As a general rule, any call to any of the following functions should be preceded by a call to `Sema.addReferenceEntry`: * `Zcu.ensureDeclAnalyzed` * `Sema.ensureDeclAnalyzed` * `Zcu.ensureFuncBodyAnalyzed` * `Zcu.ensureFuncBodyAnalysisQueued` This is not just important for error messages, but also more fundamentally for incremental compilation. When an incremental update occurs, we must determine whether any `AnalUnit` has become unreferenced: in this case, we should ignore its associated error messages, and perhaps even remove it from the binary. For this reason, we no longer store only one reference to every `AnalUnit`, but every reference. At the end of an update, `Zcu.resolveReferences` will construct the reverse mapping, and as such identify which `AnalUnit`s are still referenced. The current implementation doesn't quite do what we need for incremental compilation here, but the framework is in place. Note that `Zcu.resolveReferences` does constitute a non-trivial amount of work on every incremental update. However, for incremental compilation, this work -- which will effectively be a graph traversal over all `AnalUnit` references -- seems strictly necessary. At the moment, this work is only done if the `Zcu` has any errors, when collecting them into the final `ErrorBundle`. An unsolved problem here is how to represent inline function calls in the reference trace. If `foo` performs an inline call to `bar` which references `qux`, then ideally, `bar` would be shown on the reference trace between `foo` and `qux`, but this is not currently the case. The solution here is probably for `Zcu.Reference` to store information about the source locations of active inline calls betweeen the referencer and its reference.
A general-purpose programming language and toolchain for maintaining robust, optimal, and reusable software.
Documentation
If you are looking at this README file in a source tree, please refer to the Release Notes, Language Reference, or Standard Library Documentation corresponding to the version of Zig that you are using by following the appropriate link on the download page.
Otherwise, you're looking at a release of Zig, and you can find documentation here:
- doc/langref.html
- doc/std/index.html
Installation
A Zig installation is composed of two things:
- The Zig executable
- The lib/ directory
At runtime, the executable searches up the file system for the lib/ directory, relative to itself:
- lib/
- lib/zig/
- ../lib/
- ../lib/zig/
- (and so on)
In other words, you can unpack a release of Zig anywhere, and then begin
using it immediately. There is no need to install it globally, although this
mechanism supports that use case too (i.e. /usr/bin/zig and /usr/lib/zig/).
Building from Source
Ensure you have the required dependencies:
- CMake >= 3.15
- System C/C++ Toolchain
- LLVM, Clang, LLD development libraries == 18.x
Then it is the standard CMake build process:
mkdir build
cd build
cmake ..
make install
For more options, tips, and troubleshooting, please see the Building Zig From Source page on the wiki.
Building from Source without LLVM
In this case, the only system dependency is a C compiler.
cc -o bootstrap bootstrap.c
./bootstrap
This produces a zig2 executable in the current working directory. This is a
"stage2" build of the compiler,
without LLVM extensions, and is
therefore lacking these features:
- Release mode optimizations
- aarch64 machine code backend
@cImport/zig translate-c- Ability to compile C files
- Ability to compile assembly files
- Some ELF linking features
- Most COFF/PE linking features
- Some WebAssembly linking features
- Ability to create import libs from def files
- Automatic importlib file generation for Windows DLLs
- Ability to create static archives from object files
- Ability to compile C++, Objective-C, and Objective-C++ files
However, a compiler built this way does provide a C backend, which may be useful for creating system packages of Zig projects using the system C toolchain. In such case, LLVM is not needed!
Contributing
Zig is Free and Open Source Software. We welcome bug reports and patches from everyone. However, keep in mind that Zig governance is BDFN (Benevolent Dictator For Now) which means that Andrew Kelley has final say on the design and implementation of everything.
One of the best ways you can contribute to Zig is to start using it for an open-source personal project.
This leads to discovering bugs and helps flesh out use cases, which lead to further design iterations of Zig. Importantly, each issue found this way comes with real world motivations, making it straightforward to explain the reasoning behind proposals and feature requests.
You will be taken much more seriously on the issue tracker if you have a personal project that uses Zig.
The issue label Contributor Friendly exists to help you find issues that are limited in scope and/or knowledge of Zig internals.
Please note that issues labeled Proposal but do not also have the Accepted label are still under consideration, and efforts to implement such a proposal have a high risk of being wasted. If you are interested in a proposal which is still under consideration, please express your interest in the issue tracker, providing extra insights and considerations that others have not yet expressed. The most highly regarded argument in such a discussion is a real world use case.
For more tips, please see the Contributing page on the wiki.
Community
The Zig community is decentralized. Anyone is free to start and maintain their own space for Zig users to gather. There is no concept of "official" or "unofficial". Each gathering place has its own moderators and rules. Users are encouraged to be aware of the social structures of the spaces they inhabit, and work purposefully to facilitate spaces that align with their values.
Please see the Community wiki page for a public listing of social spaces.