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After this change, the frontend and backend cooperate to keep track of which Decls are actually emitted into the machine code. When any backend sees a `decl_ref` Value, it must mark the corresponding Decl `alive` field to true. This prevents unused comptime data from spilling into the output object files. For example, if you do an `inline for` loop, previously, any intermediate value calculations would have gone into the object file. Now they are garbage collected immediately after the owner Decl has its machine code generated. In the frontend, when it is time to send a Decl to the linker, if it has not been marked "alive" then it is deleted instead. Additional improvements: * Resolve type ABI layouts after successful semantic analysis of a Decl. This is needed so that the backend has access to struct fields. * Sema: fix incorrect logic in resolveMaybeUndefVal. It should return "not comptime known" instead of a compile error for global variables. * `Value.pointerDeref` now returns `null` in the case that the pointer deref cannot happen at compile-time. This is true for global variables, for example. Another example is if a comptime known pointer has a hard coded address value. * Binary arithmetic sets the requireRuntimeBlock source location to the lhs_src or rhs_src as appropriate instead of on the operator node. * Fix LLVM codegen for slice_elem_val which had the wrong logic for when the operand was not a pointer. As noted in the comment in the implementation of deleteUnusedDecl, a future improvement will be to rework the frontend/linker interface to remove the frontend's responsibility of calling allocateDeclIndexes. I discovered some issues with the plan9 linker backend that are related to this, and worked around them for now.
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.