CJIT: Bringing C to the Just-In-Time Era with Enhanced Usability

CJIT, or C Just in Time, emerges as a compelling project aimed at streamlining the C development workflow by offering a tiny, portable compiler and interpreter. Inspired by the principles of HolyC by Terry Davis and built upon the robust foundation of Fabrice Bellard's TinyCC, CJIT seeks to make C more accessible for rapid prototyping and instant deployment across various platforms. This initiative by Jaromil and the Dyne.org crew addresses common friction points in C development, positioning itself as a tool for quick experimentation and execution without the overhead of traditional build environments.

This article delves into CJIT's core features, its distinctions from its predecessors, and the community's reception and insights, highlighting its potential to transform how developers interact with C for scripting and rapid application development.

What is CJIT?

CJIT is presented as a single-binary C compiler and interpreter, designed for maximum portability and ease of use. It encapsulates the TinyCC compiler, along with its necessary headers and standard library, into a compact package less than 2MB in size. This design philosophy eliminates the need for complex installations, path configurations, or dedicated IDEs, making it an ideal candidate for environments where quick setup is paramount.

Its inspiration from HolyC, the C-like language used in the TempleOS operating system, suggests a focus on simplicity and direct interaction with the code. While the direct influence of HolyC's more esoteric aspects is not explicitly detailed, the spirit of a highly integrated, immediate coding experience appears to be a driving force.

Key Features and Usability Enhancements

CJIT distinguishes itself through several user experience improvements that address common pain points in C development:

• Instant Deployment: As a single executable file, CJIT requires no system-wide installation, EULA to sign, or IDE setup. This "one file <2MB big" approach ensures immediate usability.
• Cross-Platform Compatibility: It boasts support for MS/Windows, Apple/OSX, and GNU/Linux, making it a versatile tool for developers working across different operating systems.
• Multi-File Execution: Unlike standard compiler invocations, CJIT can accept wildcards to ingest multiple C source files, pre-compiled objects, or shared libraries into a single execution. Symbols exported by each file become visible to all during the same execution context.
• Automatic Library Discovery: CJIT automatically locates common system libraries for each target platform, removing the need for developers to manually specify library paths and settings.
• Dynamic Library Calling: It provides the capability to use any shared function found in dynamic libraries, extending its utility for integrating with existing system functionalities.
• Rapid Prototyping: The combination of these features enables developers to write and execute C applications with unprecedented speed, fostering a rapid prototyping workflow.

CJIT vs. TinyCC: A Deeper Dive

While CJIT is built upon TinyCC, a common question arises regarding its differentiation from simply using tcc -run. A commenter on Hacker News provided a clear summary of the distinctions:

The main difference is in usability. CJIT improves three main UX aspects for now: It works as a single executable file which embeds the TinyCC compiler, all its headers and its standard library. This way there is no need to install anything system wide, check paths and setup build folders. It supports adding multiple files into one execution: can accept wildcards to ingest anything that is a C source, a pre-compiled object or a shared library. The symbols exported by each file will be visible to all during the same execution. It finds automatically common system libraries for each target platform, avoiding the need to repeat these settings and look for the right paths.

This clarifies that CJIT is not a fundamental re-imagining of C compilation but rather a significant enhancement of the developer experience around TinyCC, focusing on convenience and reducing boilerplate.

Community Feedback and Considerations

The Hacker News discussion revealed several interesting points and questions from the community:

Portability and Dependencies

While CJIT aims for portability, some users encountered specific dependency issues. For instance, a user noted that a release explicitly for cjit-x86_64-ubuntu-24.04 did not work on Arch Linux due to a missing libgcc_s.so.1, suggesting a dlopen issue. This highlights the ongoing challenge of creating truly universal binaries in the Linux ecosystem, even for projects striving for minimal dependencies.

Self-Hosting Capabilities

A pertinent question raised was whether CJIT could compile itself, a common benchmark for compilers like GCC and LLVM. The project's FAQs do not explicitly mention this, leaving it as an intriguing area for future exploration by the community.

Potential as a Scripting Language

The idea of pairing CJIT with projects like Fil-C (a C interpreter designed for scripting) was suggested, envisioning C as a "truly bonafide scripting language." This points to a broader interest in leveraging C's power in more dynamic, script-like contexts.

Alternatives and Inspirations

Mir, another project offering tools for custom JIT including a C compiler, was mentioned as an alternative for those interested in similar capabilities. The inspiration from HolyC also sparked curiosity, with users wondering about the specific ways it influenced CJIT beyond the general concept of an immediate C environment.

Minor Observations

Some users noted minor details, such as the use of fprintf(stderr, ...) for the classic "hello, world" example in the documentation, which deviates from the more common printf. Others commented on the website's visual design, describing it as "compressed" or similar to certain AI-generated aesthetics.

Graphical Applications with SDL

CJIT also embraces the world of graphical C applications by integrating with SDL (Simple DirectMedia Layer). The project's documentation explicitly welcomes developers to this exciting domain, noting SDL's long history since 1998. This "batteries included" approach for graphical development further enhances CJIT's appeal for rapid prototyping beyond command-line tools.

Conclusion

CJIT represents a thoughtful evolution in the landscape of C development tools, focusing on an enhanced user experience through portability, simplified deployment, and intelligent dependency management. By building on TinyCC and drawing inspiration from HolyC, it offers a compelling solution for developers seeking to leverage C's performance and control in a more agile, just-in-time fashion. While challenges like universal binary compatibility persist, CJIT's core value proposition of making C development faster and more accessible for rapid prototyping and scripting remains strong, inviting developers to explore its capabilities for a wide range of applications.