TL;DR
The Zig project has significantly improved its ELF linker, enabling rapid incremental rebuilds on x86_64 Linux. This development enhances productivity, especially during debugging, but still lacks DWARF debug info support. Further updates are expected.
Zig’s new ELF linker now supports fast incremental compilation on x86_64 Linux, allowing developers to rebuild projects in milliseconds. This marks a major step forward in Zig’s build performance, with ongoing work to add DWARF debug information support.
Matthew Lugg, the primary developer behind the ELF linker improvements, announced that the new linker, introduced in Zig 0.16.0, now successfully supports building the self-hosted Zig compiler with LLVM and LLD libraries enabled. This milestone demonstrates the linker’s capability to handle complex build tasks involving external libraries and C sources.
One of the key features of the updated ELF linker is its support for fast incremental compilation. Tests on x86_64 Linux show that rebuilds involving external libraries and C sources can now occur in under 300 milliseconds, significantly reducing development time during debugging and iterative testing. For example, building a simple Zig project or Andrew Kelley’s Tetris clone now takes roughly 30ms to 244ms, depending on the complexity.
However, the current implementation still lacks support for generating DWARF debug information for Zig code, which is a priority for the next phase of development. Despite this, the immediate benefits of instant rebuilds are already impacting developer workflows, especially for debugging and rapid iteration.
Why It Matters
This development is significant because it addresses a long-standing bottleneck in Zig’s build process. Fast incremental compilation can drastically improve productivity, particularly in debugging scenarios where frequent rebuilds are necessary. The ability to rebuild in milliseconds makes Zig more appealing for larger projects and iterative development.
Furthermore, this enhancement aligns Zig more closely with modern build systems that emphasize speed and efficiency, potentially attracting more developers and projects to adopt Zig as a primary language for systems programming and embedded development.
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Background
The ELF linker improvements follow previous updates to Zig’s build system, including a major rework announced on May 26, 2026, that separated the build configuration from the execution process, resulting in faster build times overall. Prior to this, Zig’s build process involved compiling large parts of the build system in Debug mode, which could slow down development workflows. The recent changes aim to optimize this process further, with the new linker forming a core part of this effort.
Since the initial introduction of the ELF linker in Zig 0.16.0, the feature set has been limited primarily to internal Zig code linking. The recent progress now enables external library linking and C source integration, broadening the scope of projects that can benefit from the new linker features.
“The biggest missing feature of this linker implementation right now is support for generating DWARF debug information for Zig code—that’s my next priority.”
— Matthew Lugg
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What Remains Unclear
It is not yet clear when DWARF debug information support will be fully implemented in the ELF linker. Developer feedback and bug reports are encouraged to refine the feature before release.
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What’s Next
Next steps include completing DWARF debug info support, testing the linker with more complex projects, and integrating these improvements into stable Zig releases. Developers are advised to try out the current nightly builds if they are on x86_64 Linux and report issues.
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Key Questions
What is the main benefit of the new ELF linker?
The main benefit is support for fast incremental compilation, enabling rebuilds in milliseconds, which improves development speed and debugging efficiency.
Does the new linker support debug information now?
No, support for DWARF debug information is still being developed and is not yet available. It remains a priority for future updates.
Can I try these features in stable Zig releases?
Currently, these improvements are available in the master branch or nightly builds. They are not yet part of the official stable releases but are expected to be included in Zig 0.17.0.
Will these improvements work on platforms other than Linux?
The current development and testing focus on x86_64 Linux. Support for other platforms has not been confirmed and remains to be seen.
Source: Hacker News
