Merge #390

390: Spawn and schedule from anywhere r=AfoHT a=korken89

This PR moves RTIC to the spawn and schedule from anywhere syntax.

Notable changes:
 * We do no longer support non-`Send` types.
 * Some extra code is generated as any task may spawn/schedule any task. However Rust/LLVM does a great job optimizing away non used instantiations (no real code-size difference observed).
 * Worst case priority inversion has increased, but it is now predictable.

Upsides:
 * With this we should be able to support async/await.
 * RTIC tasks can now be callbacks (spawned and scheduled).
 * RTIC tasks can be stored.

Needs the following PR to land first: https://github.com/rtic-rs/rtic-syntax/pull/34

The following now works:

```rust
#[rtic::app(device = lm3s6965, monotonic = rtic::cyccnt::CYCCNT)]
mod app {
    #[init]
    fn init(mut cx: init::Context) -> init::LateResources {
        // Init stuff...

        // New spawn syntax
        foo::spawn().unwrap();

        // New schedule syntax
        bar::schedule(now + 4_000_000.cycles()).unwrap();

        init::LateResources {}
    }

    #[task]
    fn foo(_: foo::Context) {}

    #[task]
    fn bar(_: bar::Context) {}

    extern "C" {
        fn SSI0();
    }
}

```

Co-authored-by: Per Lindgren <per.lindgren@ltu.se>
Co-authored-by: Emil Fresk <emil.fresk@gmail.com>

1 files changed, 2 insertions, 16 deletions

diff --git a/macros/src/codegen.rs b/macros/src/codegen.rs
index a256ac75..0cff5bbc 100644
--- a/macros/src/codegen.rs
+++ b/macros/src/codegen.rs
@@ -15,11 +15,7 @@ mod post_init;
 mod pre_init;
 mod resources;
 mod resources_struct;
-mod schedule;
-mod schedule_body;
 mod software_tasks;
-mod spawn;
-mod spawn_body;
 mod timer_queue;
 mod util;
 
@@ -115,15 +111,9 @@ pub fn app(app: &App, analysis: &Analysis, extra: &Extra) -> TokenStream2 {
     ) = software_tasks::codegen(app, analysis, extra);
 
     let mod_app_dispatchers = dispatchers::codegen(app, analysis, extra);
-
-    let mod_app_spawn = spawn::codegen(app, analysis, extra);
-
     let mod_app_timer_queue = timer_queue::codegen(app, analysis, extra);
-
-    let mod_app_schedule = schedule::codegen(app, extra);
-
-    let user_imports = app.user_imports.clone();
-    let user_code = app.user_code.clone();
+    let user_imports = &app.user_imports;
+    let user_code = &app.user_code;
     let name = &app.name;
     let device = extra.device;
 
@@ -187,12 +177,8 @@ pub fn app(app: &App, analysis: &Analysis, extra: &Extra) -> TokenStream2 {
 
             #(#mod_app_dispatchers)*
 
-            #(#mod_app_spawn)*
-
             #(#mod_app_timer_queue)*
 
-            #(#mod_app_schedule)*
-
             #(#mains)*
         }
     )