Chandler CarruthandJon Ross-Perkins
13502b7c89
This restores the symlinks for the installation, but teaches the busybox info search to look for a relative path to the busybox binary itself before walking through symlinks. This let's it find the tree structure when directly invoking `prefix_root/bin/carbon` or similar, either inside of a Bazel rule or from the command line, and mirrors how we expect the installed tree to look. This works even when Bazel resolves the symlink target fully, and potentially to something nonsensical like a CAS file. In order to make a convenient Bazel target that can be used with `bazel run //toolchain`, this adds an override to explicitly set the desired argv[0] to use when selecting a mode for the busybox and a busybox binary. Currently, the workaround uses an environment variable because that required the least amount of plumbing, and seems a useful override mechanism generally, but I'm open to other approaches. This should allow a few things to work a bit more nicely: - It should handle sibling symlinks like `clang++` to `clang` or `ld.lld` to `lld`, where that symlink in turn points at the busybox. We want to use *initial* `argv[0]` value to select the mode there. - It avoids bouncing through Python (or other subprocesses) when invoking the `carbon` binary in Bazel rules, which will be nice for building the example code and benchmarking. It does come at a cost of removing one feature: the initial symlink can't be some unrelated alias like `my_carbon_symlink` -- we expect the *first* argv[0] name to have the meaningful filename for selecting a busybox mode. It also trades the complexity of the Python script for some complexity in the busybox search in order to look for a relative `carbon-busybox` binary. On the whole, I think that tradeoff is worthwhile, but it isn't free. --------- Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Docs
This directory contains current, accepted documentation underpinning Carbon. These documents cover all aspects of Carbon ranging from the project down to detailed designs for specific language features.
If you're trying to learn more about Carbon, we recommend starting at
/README.md.
Design
Carbon language's design and rationale are documented in the
design/ directory. This documentation is intended to
support the following audiences:
- People who wish to determine whether Carbon would be the right choice for a project compared to other existing languages.
- People working on the evolution of the Carbon language who wish to understand the rationale and motivation for existing design decisions.
- People working on a specification or implementation of the Carbon language who need a detailed understanding of the intended design.
- People writing Carbon code who wish to understand why the language rules are the way they are.
This is in contrast to proposals, which document the individual decisions that led to this design (along with other changes to the Carbon project), including the rationale and alternatives considered.
Project
The project/ directory contains project-related
documentation for Carbon, including:
- goals, and the principles and roadmap derived from those goals,
- how the project works, and
- how to contribute.
Guides
The guides/ directory contains to-be-written end-user
documentation for developers writing programs in Carbon.
Spec
The spec/ directory contains the to-be-written formal
specification of the Carbon language. This is for implementers of compilers or
other tooling. This is intended to complement the interactive
language explorer tool.