Improve documentation of Rust version related variables #123
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jschwe
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Jan 7, 2022
jschwe
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- Document the version related variables that corrosion (FindRust) provides
- Improve the Rust_IS_NIGHTLY variable by always defining it (allows testing wether corrosion is new enough to set this variable)
- Add variables to expose the LLVM version used by rust. Useful e.g. for cross-language lto, where you want to be sure that the llvm version on both sides matches.
It may be useful to know the LLVM version in CMake, e.g. if one wants to use cross-language LTO to ensure that the same version of LLVM is used on both sides. Signed-off-by: Jonathan Schwender <[email protected]>
Explicitly setting the variable to 0 allows users to check if corrosion defines the variable at all. This can be used to test if the corrosion version in use supports Rust_IS_NIGHTLY or needs to be updated. Signed-off-by: Jonathan Schwender <[email protected]> Improve documentation Signed-off-by: Jonathan Schwender <[email protected]>
Conditionally enabling some code depending on the rust version is pretty common, so it makes sense to document these variables. Signed-off-by: Jonathan Schwender <[email protected]>
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| @@ -231,6 +231,8 @@ if (_RUSTC_VERSION_RAW MATCHES "rustc ([0-9]+)\\.([0-9]+)\\.([0-9]+)(-nightly)?" | |||
| set(Rust_VERSION "${Rust_VERSION_MAJOR}.${Rust_VERSION_MINOR}.${Rust_VERSION_PATCH}") | |||
| if(CMAKE_MATCH_4) | |||
| set(Rust_IS_NIGHTLY 1) | |||
| else() | |||
| set(Rust_IS_NIGHTLY 0) | |||
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Will that cause problem for people doing
if(Rust_IS_NIGHTLY) or is 0 falsy?
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Yes, 0 evaluates to false. From the documentation
False if the constant is 0, OFF, NO, FALSE, N, IGNORE, NOTFOUND, the empty string, or ends in the suffix -NOTFOUND
| @@ -248,6 +250,18 @@ else() | |||
| ) | |||
| endif() | |||
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| if (_RUSTC_VERSION_RAW MATCHES "LLVM version: ([0-9]+)\\.([0-9]+)\\.([0-9]+)") | |||
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do users need to care about the LLVM version.
I guess you added that because you have an usecase.
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My usecase is cross-language LTO. It requires that the LLVM version on both sides matches, so I need to know the version of LLVM used by rust.
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@ogoffart Are there still any open points from you, or could I go ahead and merge this? |
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No more open points. Thanks for the patch |
