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The mechanism behind initializing a union's tag is a bit complicated, depending on whether the union is initialized at runtime, forced comptime, or implicit comptime. `coerce_result_ptr` now does not force a block to be a runtime context; instead of adding runtime instructions directly, it forwards analysis to the respective functions for initializing optionals and error unions. `validateUnionInit` now has logic to still emit a runtime `set_union_tag` instruction even if the union pointer is comptime-known, for the case of a pointer that is not comptime mutable, such as a variable or the result of `@intToPtr`. `validateStructInit` looks for a completely different pattern now; it now handles the possibility of the corresponding AIR instruction for the `field_ptr` to be missing or the corresponding `store` to be missing. See the new comment added to the function for more details. An equivalent change should probably be made to `validateArrayInit`. `analyzeOptionalPayloadPtr` and `analyzeErrUnionPayloadPtr` functions now emit a `optional_payload_ptr_set` or `errunion_payload_ptr_set` instruction respectively if `initializing` is true and the pointer value is not comptime-mutable. `storePtr2` now tries the comptime pointer store before checking if the element type has one possible value because the comptime pointer store can have side effects of setting a union tag, setting an optional payload non-null, or setting an error union to be non-error. The LLVM backend `lowerParentPtr` function is improved to take into account the differences in how the LLVM values are lowered depending on the Zig type. It now handles unions correctly as well as additionally handling optionals and error unions. In the LLVM backend, the instructions `optional_payload_ptr_set` and `errunion_payload_ptr_set` check liveness analysis and only do the side effects in the case the result of the instruction is unused. A few wasm and C backend test cases regressed, but they are due to TODOs in lowering of constants, so this is progress.
A general-purpose programming language and toolchain for maintaining robust, optimal, and reusable software.
Resources
- Introduction
- Download & Documentation
- Chapter 0 - Getting Started | ZigLearn.org
- Community
- Contributing
- Code of Conduct
- Frequently Asked Questions
- Community Projects
Installation
- download a pre-built binary
- install from a package manager
- build from source
- bootstrap zig for any target
License
The ultimate goal of the Zig project is to serve users. As a first-order effect, this means users of the compiler, helping programmers to write better software. Even more important, however, are the end-users.
Zig is intended to be used to help end-users accomplish their goals. Zig should be used to empower end-users, never to exploit them financially, or to limit their freedom to interact with hardware or software in any way.
However, such problems are best solved with social norms, not with software licenses. Any attempt to complicate the software license of Zig would risk compromising the value Zig provides.
Therefore, Zig is available under the MIT (Expat) License, and comes with a humble request: use it to make software better serve the needs of end-users.
This project redistributes code from other projects, some of which have other licenses besides MIT. Such licenses are generally similar to the MIT license for practical purposes. See the subdirectories and files inside lib/ for more details.