Remove unnecessary detail in building chapter

Most of these details were not helpful or necessary for building the compiler for the first time.
This section comes very early in the guide and is meant to be a tutorial, so being concise is very important.
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Joshua Nelson 2022-12-08 09:41:21 -06:00 committed by Joshua Nelson
parent 84eea0d580
commit b36e2ff71d
1 changed files with 16 additions and 71 deletions

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@ -24,34 +24,10 @@ cd rust
## Create a `config.toml`
To start, run `./x.py setup`. This will do some initialization and create a
`config.toml` for you with reasonable defaults. These defaults are specified
indirectly via the `profile` setting, which points to one of the TOML files in
`src/bootstrap/defaults.`
`config.toml` for you with reasonable defaults.
Alternatively, you can write `config.toml` by hand. See `config.toml.example`
for all the available settings and explanations of them. The following settings
are of particular interest, and `config.toml.example` has full explanations.
You may want to change some of the following settings (and possibly others, such as
`llvm.ccache`):
```toml
[llvm]
# Whether to use Rust CI built LLVM instead of locally building it.
download-ci-llvm = true # Download a pre-built LLVM?
assertions = true # LLVM assertions on?
ccache = "/path/to/ccache" # Use ccache when building LLVM?
[rust]
debug-logging = true # Leave debug! and trace! calls in rustc?
incremental = true # Build rustc with incremental compilation?
```
If you set `download-ci-llvm = true`, in some circumstances, such as when
updating the version of LLVM used by `rustc`, you may want to temporarily
disable this feature. See the ["Updating LLVM" section] for more.
["Updating LLVM" section]: ../backend/updating-llvm.md#feature-updates
for all the available settings and explanations of them. See `src/bootstrap/defaults` for common settings to change.
If you have already built `rustc` and you change settings related to LLVM, then you may have to
execute `rm -rf build` for subsequent configuration changes to take effect. Note that `./x.py
@ -59,17 +35,13 @@ clean` will not cause a rebuild of LLVM.
## What is `x.py`?
`x.py` is the script used to orchestrate the tooling in the `rustc` repository.
It is the script that can build docs, run tests, and compile `rustc`.
It is the now preferred way to build `rustc` and it replaces the old makefiles
from before. Below are the different ways to utilize `x.py` in order to
effectively deal with the repo for various common tasks.
`x.py` is the build tool for the `rust` repository. It can build docs, run tests, and compile the
compiler and standard library.
This chapter focuses on the basics to be productive, but
if you want to learn more about `x.py`, read its README.md
[here](https://github.com/rust-lang/rust/blob/master/src/bootstrap/README.md).
To read more about the bootstrap process and why `x.py` is necessary,
[read this chapter][bootstrap].
if you want to learn more about `x.py`, [read this chapter][bootstrap].
[bootstrap]: ./bootstrapping.md
### Running `x.py` slightly more conveniently
@ -79,48 +51,14 @@ of a checkout. It also looks up the appropriate version of `python` to use.
You can install it with `cargo install --path src/tools/x`.
[bootstrap]: ./bootstrapping.md
## Building the Compiler
To build a compiler, run `./x.py build`. This will build up to the stage1 compiler,
including `rustdoc`, producing a usable compiler toolchain from the source
code you have checked out.
Note that building will require a relatively large amount of storage space.
You may want to have upwards of 10 or 15 gigabytes available to build the compiler.
There are many flags you can pass to the build command of `x.py` that can be
beneficial to cutting down compile times or fitting other things you might
need to change. They are:
```txt
Options:
-v, --verbose use verbose output (-vv for very verbose)
-i, --incremental use incremental compilation
--config FILE TOML configuration file for build
--build BUILD build target of the stage0 compiler
--host HOST host targets to build
--target TARGET target targets to build
--on-fail CMD command to run on failure
--stage N stage to build
--keep-stage N stage to keep without recompiling
--src DIR path to the root of the Rust checkout
-j, --jobs JOBS number of jobs to run in parallel
-h, --help print this help message
```
For hacking, often building the stage 1 compiler is enough, which saves a lot
of time. But for final testing and release, the stage 2 compiler is used.
`./x.py check` is really fast to build the Rust compiler.
It is, in particular, very useful when you're doing some kind of
"type-based refactoring", like renaming a method, or changing the
signature of some function.
Once you've created a `config.toml`, you are now ready to run
`x.py`. There are a lot of options here, but let's start with what is
probably the best "go to" command for building a local rust:
probably the best "go to" command for building a local compiler:
```bash
./x.py build library
@ -144,6 +82,10 @@ see [the section on avoiding rebuilds for std][keep-stage].
[keep-stage]: ./suggested.md#faster-builds-with---keep-stage
Sometimes you don't need a full build. When doing some kind of
"type-based refactoring", like renaming a method, or changing the
signature of some function, you can use `./x.py check` instead for a much faster build.
Note that this whole command just gives you a subset of the full `rustc`
build. The **full** `rustc` build (what you get with `./x.py build
--stage 2 compiler/rustc`) has quite a few more steps:
@ -165,6 +107,9 @@ Instead, you can just build using the bootstrap compiler.
./x.py build --stage 0 library
```
If you choose the `library` profile when running `x.py setup`, you can omit `--stage 0` (it's the
default).
## Creating a rustup toolchain
Once you have successfully built `rustc`, you will have created a bunch
@ -273,7 +218,7 @@ in other sections:
- `./x.py build` builds everything using the stage 1 compiler,
not just up to `std`
- `./x.py build --stage 2` builds everything with the stage 2 compiler including
`rustdoc` (which doesn't take too long)
`rustdoc`
- Running tests (see the [section on running tests](../tests/running.html) for
more details):
- `./x.py test library/std` runs the unit tests and integration tests from `std`