search

Rahix / avr-device

Register access crate for AVR microcontrollers
Apache License 2.0
168 stars 67 forks source link

Move PAM generation to build time, optimizing download size #157

Open LuigiPiucco opened 2 months ago

LuigiPiucco commented 2 months ago

Although from the titles alone it may seem unrelated to the issue, the original goal was to fix #59. The approach taken, as suggested in that thread, is to generate the Peripheral Access Modules (PAMs) after the user has downloaded the package, in an automated fashion. So, instead of shipping the modules generated "by hand" (with semi-automation actually, but still), we ship the ATDF sources from which they are generated. When running build either in the crate root or as a dependency, the build.rs script outputs a module for the selected MCU into a known path. The generation steps are described in the README.

The result of this is that the packaged .crate file does become much smaller, just short of 5 times (4.875...). Compilation time increases, of course, in particular as a fault of the build script. This could be improved by using the executable versions of svd2rust, svdtools and atdf2svd, but that would greatly reduce reproducibility. rustfmt is used via the executable, since it does not provide a library API, but in that case it should be fine, since anyone with a toolchain capable of compiling to AVR probably also has access to rustfmt.

The commit changing the example from a crate to an actual Cargo example, while technically not necessary, makes testing the use of the crate as a dependency more convenient.

For a reference of crate size, see https://github.com/Rahix/avr-device/issues/59#issuecomment-2110843733.

LuigiPiucco commented 1 month ago

@Rahix just a reminder about this.