document combination of flags #756
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Fixes #646 |
antoyo
reviewed
Sep 3, 2025
| Rustup ships these libraries **pre-compiled with LLVM**. | ||
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| Because **rustc_codegen_gcc** replaces LLVM with the GCC backend, the shipped | ||
| LLVM artefacts are **incompatible**. |
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They should be compatible. If they are not, this would be an ABI bug.
| * the user switches toolchains / updates submodules. | ||
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| Both backend and sysroot can be built using different [profiles](https://doc.rust-lang.org/cargo/reference/profiles.html#default-profiles). | ||
| That is exactly what the `--sysroot`, `--release-sysroot` and `--release` flag supported by the frontend script `y.sh` take care of. |
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Suggested change
| That is exactly what the `--sysroot`, `--release-sysroot` and `--release` flag supported by the frontend script `y.sh` take care of. | |
| That is exactly what the `--sysroot`, `--release-sysroot` and `--release` flag supported by the build system script `y.sh` take care of. |
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| | Command | Backend Profile | Sysroot Profile | Usage Scenario | | ||
| |--------------------------------------------|-------------------------------|----------------------------------|------------------------------------------------------------| | ||
| | `./y.sh build` | dev (optimized + debuginfo) | X | Optimize backend with debug capabilities | |
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According to the Cargo.toml, only the dependencies are built with optimizations.
| |--------------------------------------------|-------------------------------|----------------------------------|------------------------------------------------------------| | ||
| | `./y.sh build` | dev (optimized + debuginfo) | X | Optimize backend with debug capabilities | | ||
| | `./y.sh build --release` | release (optimized) | X | Optimize backend without rebuilding sysroot | | ||
| | `./y.sh build --release --release-sysroot`| release (optimized) | X | Same as --release | |
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--release-sysroot should not be used without --sysroot, so I would remove this line and the other doing this from this table and perhaps specify that this outside the table.
| | `./y.sh build` | dev (optimized + debuginfo) | X | Optimize backend with debug capabilities | | ||
| | `./y.sh build --release` | release (optimized) | X | Optimize backend without rebuilding sysroot | | ||
| | `./y.sh build --release --release-sysroot`| release (optimized) | X | Same as --release | | ||
| | `./y.sh build --release --sysroot` | release (optimized) | dev (unoptimized + debuginfo) | Optimize backend for release without full sysroot rebuild | |
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This should build the sysroot since the --sysroot flag is provided.
| | `./y.sh build --release` | release (optimized) | X | Optimize backend without rebuilding sysroot | | ||
| | `./y.sh build --release --release-sysroot`| release (optimized) | X | Same as --release | | ||
| | `./y.sh build --release --sysroot` | release (optimized) | dev (unoptimized + debuginfo) | Optimize backend for release without full sysroot rebuild | | ||
| | `./y.sh build --sysroot` | dev (optimized + debuginfo) | dev (unoptimized + debuginfo) | Full debug capabilities with optimized backend | |
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This should build the sysroot since the --sysroot flag is provided.
| | `./y.sh build --release --sysroot` | release (optimized) | dev (unoptimized + debuginfo) | Optimize backend for release without full sysroot rebuild | | ||
| | `./y.sh build --sysroot` | dev (optimized + debuginfo) | dev (unoptimized + debuginfo) | Full debug capabilities with optimized backend | | ||
| | `./y.sh build --release-sysroot` | dev (optimized + debuginfo) | X | Build only optimized backend with debug capabilities | | ||
| | `./y.sh build --release-sysroot --sysroot`| dev (optimized + debuginfo) | release (optimized) | Build optimized backend and sysroot for debugging and release, respectively | |
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This should only build a release sysroot, not a debug sysroot.
And this builds a "debug" (well, dependencies compiled with optimizations + backend not optimized) backend.
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| --release : Build and optimize the backend in release mode | ||
| --sysroot : When used on its own, build both | ||
| sysroot and backend in dev. mode. Only the backend is optimized. | ||
| When used together with --release, build and optimize the backend | ||
| in release mode instead of in dev. mode. | ||
| When used together with --release-sysroot, | ||
| build and optimize the sysroot in release mode instead of in dev. mode | ||
| --release-sysroot : When used on its own, build and optimize only the backend in dev. mode. | ||
| When combined with --release, it has no effect. | ||
| When combined with --sysroot, additionally | ||
| build and optimize the sysroot in release mode |
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I'll let you update this to reflect the above comments.
Also, most of these flags will only work with the build command, right?
If so, they should only be shown in the help of the build command.
Good points :), thanks! |
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-Documented in CONTRIBUTING.md the role of sysroot and the meaning of different flags combination used in frontend script y.sh
-Updated help output for binary file y (build_system/target/release/y build --help)