|
1 | | -# GCC codegen backend tests |
| 1 | +# GCC codegen backend |
2 | 2 |
|
3 | | -To test the GCC codegen backend, you need to add `"gcc"` into the `rust.codegen-backends` |
4 | | -setting in `bootstrap.toml`: |
| 3 | +If you ran into an error related to tests executed with the GCC codegen backend on CI, |
| 4 | +you can use the following command to run tests locally using the GCC backend: |
| 5 | + |
| 6 | +```bash |
| 7 | +./x test tests/ui --set 'rust.codegen-backends = ["llvm", "gcc"]' --test-codegen-backend gcc |
| 8 | +``` |
| 9 | + |
| 10 | +Below, you can find more information about how to configure the GCC backend in bootstrap. |
| 11 | + |
| 12 | +## Choosing which codegen backends are built |
| 13 | + |
| 14 | +The `rust.codegen-backends = [...]` bootstrap option affects which codegen backends will be built and |
| 15 | +included in the sysroot of the produced `rustc`. To use the GCC codegen backend, `"gcc"` has to |
| 16 | +be included in this array in `bootstrap.toml`: |
5 | 17 |
|
6 | 18 | ```toml |
7 | 19 | rust.codegen-backends = ["llvm", "gcc"] |
8 | 20 | ``` |
9 | 21 |
|
10 | | -If you don't want to change your `bootstrap.toml` file, you can alternatively run your `x.py` |
| 22 | +If you don't want to change your `bootstrap.toml` file, you can alternatively run your `x` |
11 | 23 | commands with `--set rust.codegen-backends=["llvm", "gcc"]'`. For example: |
12 | 24 |
|
13 | 25 | ```bash |
14 | | -x.py test --set 'rust.codegen-backends=["llvm", "gcc"]' |
| 26 | +./x build --set 'rust.codegen-backends=["llvm", "gcc"]' |
15 | 27 | ``` |
16 | 28 |
|
17 | | -If you don't want to build `gcc` yourself, you also need to set: |
| 29 | +The first backend in the `codegen-backends` array will determine which backend will be used as the |
| 30 | +*default backend* of the built `rustc`. This also determines which backend will be used to compile the |
| 31 | +stage 1 standard library (or anything built in stage 2+). To produce `rustc` that uses the GCC backend |
| 32 | +by default, you can thus put `"gcc"` as the first element of this array: |
18 | 33 |
|
19 | | -```toml |
20 | | -gcc.download-ci-gcc = true |
| 34 | +```bash |
| 35 | +./x build --set 'rust.codegen-backends=["gcc"]' library |
21 | 36 | ``` |
22 | 37 |
|
23 | | -Then when running tests, add the `--test-codegen-backend gcc` option. For example: |
| 38 | +## Choosing the codegen backend used in tests |
| 39 | + |
| 40 | +To run compiler tests with the GCC codegen backend being used to build the test Rust programs, you can use the |
| 41 | +`--test-codegen-backend` flag: |
24 | 42 |
|
25 | 43 | ```bash |
26 | | -./x.py test tests/ui --test-codegen-backend gcc |
| 44 | +./x test tests/ui --test-codegen-backend gcc |
27 | 45 | ``` |
28 | 46 |
|
29 | | -If you want to build the sysroot using the GCC backend, you need to set it first |
30 | | -in `rust.codegen-backends`: |
| 47 | +Note that in order for this to work, the tested compiler must have the GCC codegen backend available in its sysroot |
| 48 | +directory. You can achieve that using the [instructions above](#choosing-which-codegen-backends-are-built). |
31 | 49 |
|
32 | | -```toml |
33 | | -rust.codegen-backends = ["llvm", "gcc"] |
34 | | -``` |
| 50 | +## Downloading GCC from CI |
| 51 | + |
| 52 | +The `gcc.download-ci-gcc` bootstrap option controls if GCC (which is a dependency of the GCC codegen backend) |
| 53 | +will be downloaded from CI or built locally. The default value is `true`, which will download GCC from CI |
| 54 | +if there are no local changes to the GCC sources and the given host target is available on CI. |
| 55 | + |
| 56 | +Note that GCC can currently only be downloaded from CI for the `x86_64-unknown-linux-gnu` target. |
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