593: RTIC macro expansion: Try to find target-dir r=korken89 a=AfoHT
Seems over-engineered, but for projects where
```
[build]
target-dir = "target"
```
is set to anything other than default `target` RTIC did simply not produce any `rtic-expansion.rs`.
This changes the approach to not giving up if not finding `target/` by looking at `OUT_DIR` and traversing back until `TARGET` is found.
As the `TARGET` target-triple variable is not available, approximate the `TARGET` folder (found in `target-dir`) with `s.starts_with("thumbv")`.
`target-dir` as set in `.cargo/config` will now be the parent directory of the `Path` ending with `TARGET`
## Example running with default target:
```
cortex-m-rtic on expansionoutdir [$!?] is 📦 v1.0.0 via R v1.58.0 took 4s
❯ cargo build --example spawn --target thumbv7em-none-eabihf
OUT_DIR
"/home/henrik/rust/rtic/cortex-m-rtic/target/thumbv7em-none-eabihf/debug/build/cortex-m-rtic-5bd81e8412a790d5/out"
target/ exists
Write file:
target/rtic-expansion.rs
Finished dev [unoptimized + debuginfo] target(s) in 7.20s
```
## Contrived example
With `.cargo/config` containing:
```
[build]
target-dir = "/tmp/cargothingy/../rust/./target/cargo"`
```
```
cortex-m-rtic on expansionoutdir [$!?] is 📦 v1.0.0 via R v1.58.0 took 3s
❯ cargo build --example spawn --target thumbv7em-none-eabihf
OUT_DIR
"/tmp/cargothingy/../rust/./target/cargo/thumbv7em-none-eabihf/debug/build/cortex-m-rtic-5bd81e8412a790d5/out"
"/tmp/cargothingy/../rust/./target/cargo"
Write file:
/tmp/cargothingy/../rust/./target/cargo/rtic-expansion.rs
Finished dev [unoptimized + debuginfo] target(s) in 6.42s
```
## Less extreme with relative paths
```
[build]
target-dir = "../../cargothingy/target/buildfiles/and-stuff"
```
```
OUT_DIR
"/home/henrik/rust/rtic/cortex-m-rtic/../../cargothingy/target/buildfiles/and-stuff/thumbv7em-none-eabihf/debug/build/cortex-m-rtic-5bd81e8412a790d5/out"
"/home/henrik/rust/rtic/cortex-m-rtic/../../cargothingy/target/buildfiles/and-stuff"
Write file:
/home/henrik/rust/rtic/cortex-m-rtic/../../cargothingy/target/buildfiles/and-stuff/rtic-expansion.rs
Finished dev [unoptimized + debuginfo] target(s) in 6.78s
```
Note: If the user creates a folder named target in the same directory where `Cargo.toml`/crate root is, that will be used for storing the expansion.
```
<...>
OUT_DIR
"/home/henrik/rust/rtic/cortex-m-rtic/../../cargothingy/target/buildfiles/and-stuff/thumbv7em-none-eabihf/debug/build/cortex-m-rtic-5bd81e8412a790d5/out"
target/ exists
Write file:
target/rtic-expansion.rs
Finished dev [unoptimized + debuginfo] target(s) in 6.62s
```
Co-authored-by: Henrik Tjäder <henrik@grepit.se>
covers
- initialization and configuration of the timer; this is now a responsibility of
the application author
- correctness of `Monotonic::now()` in `#[init]`
- safety of `Monotonic::reset()`
closes#251
This commit:
- Implements RFC 147: "all functions must be safe"
- Implements RFC 155: "explicit Context parameter"
- Implements the pending breaking change #141: reject assign syntax in `init`
(which was used to initialize late resources)
- Refactors code generation to make it more readable -- there are no more random
identifiers in the output -- and align it with the book description of RTFM
internals.
- Makes the framework hard depend on `core::mem::MaybeUninit` and thus will
require nightly until that API is stabilized.
- Fixes a ceiling analysis bug where the priority of the system timer was not
considered in the analysis.
- Shrinks the size of all the internal queues by turning `AtomicUsize` indices
into `AtomicU8`s.
- Removes the integration with `owned_singleton`.
