bc78d8efdb
A new `Legalize.Feature` tag is introduced for each float bit width (16/32/64/80/128). When e.g. `soft_f16` is enabled, all arithmetic and comparison operations on `f16` are converted to calls to the appropriate compiler_rt function using the new AIR tag `.legalize_compiler_rt_call`. This includes casts where the source *or* target type is `f16`, or integer<=>float conversions to or from `f16`. Occasionally, operations are legalized to blocks because there is extra code required; for instance, legalizing `@floatFromInt` where the integer type is larger than 64 bits requires calling an arbitrary-width integer conversion function which accepts a pointer to the integer, so we need to use `alloc` to create such a pointer, and store the integer there (after possibly zero-extending or sign-extending it). No backend currently uses these new legalizations (and as such, no backend currently needs to implement `.legalize_compiler_rt_call`). However, for testing purposes, I tried modifying the self-hosted x86_64 backend to enable all of the soft-float features (and implement the AIR instruction). This modified backend was able to pass all of the behavior tests (except for one `@mod` test where the LLVM backend has a bug resulting in incorrect compiler-rt behavior!), including the tests specific to the self-hosted x86_64 backend. `f16` and `f80` legalizations are likely of particular interest to backend developers, because most architectures do not have instructions to operate on these types. However, enabling *all* of these legalization passes can be useful when developing a new backend to hit the ground running and pass a good amount of tests more easily.
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, so you can find the language
reference at doc/langref.html, and the standard library documentation by
running zig std, which will open a browser tab.
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 == 21.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
- Some ELF linking features
- Some COFF/PE linking features
- Some WebAssembly linking features
- Ability to create static archives from object files
- Ability to compile assembly files
- Ability to compile C, C++, Objective-C, and Objective-C++ files
Even when built this way, Zig provides an LLVM backend that produces bitcode files, which may be optimized and compiled into object files via a system Clang package. This can be used to produce system packages of Zig applications without the Zig package dependency on LLVM.
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.