Monomorphize various things (bevyengine#1914)

Based on bevyengine#1910

This shrinks breakout from 310k to 293k. Most of the win is in outlining the drop glue of `App`. The other two commits save about 800 bytes total when using two empty systems and two simple resources.

After this PR the full disassembly for

```rust
fn main() {
    App::build().run();
}
```

is about as minimal as it gets, so pretty much all other costs scale linear in the amount of resources, systems, etc.

```asm
0000000000001100 <_ZN4core3ptr54drop_in_place$LT$bevy_app..app_builder..AppBuilder$GT$17h76850422c20653deE>:
    1100:       ff 25 52 21 00 00       jmpq   *0x2152(%rip)        # 3258 <_ZN60_$LT$bevy_app..app..App$u20$as$u20$core..ops..drop..Drop$GT$4drop17h67d177ae549d917bE@Base>
    1106:       cc                      int3   
    1107:       cc                      int3   
    1108:       cc                      int3   
    1109:       cc                      int3   
    110a:       cc                      int3   
    110b:       cc                      int3   
    110c:       cc                      int3   
    110d:       cc                      int3   
    110e:       cc                      int3   
    110f:       cc                      int3   

0000000000001110 <_ZN8breakout4main17h7cbe07b319de1042E>:
    1110:       53                      push   %rbx
    1111:       48 81 ec 00 03 00 00    sub    $0x300,%rsp
    1118:       48 8d 5c 24 08          lea    0x8(%rsp),%rbx
    111d:       48 89 df                mov    %rbx,%rdi
    1120:       ff 15 3a 21 00 00       callq  *0x213a(%rip)        # 3260 <_ZN8bevy_app3app3App5build17h8b0ea6be9050d6ccE@Base>
    1126:       48 89 df                mov    %rbx,%rdi
    1129:       ff 15 39 21 00 00       callq  *0x2139(%rip)        # 3268 <_ZN8bevy_app11app_builder10AppBuilder3run17hfc8cf50692acdbdeE@Base>
    112f:       48 8d 7c 24 08          lea    0x8(%rsp),%rdi
    1134:       ff 15 1e 21 00 00       callq  *0x211e(%rip)        # 3258 <_ZN60_$LT$bevy_app..app..App$u20$as$u20$core..ops..drop..Drop$GT$4drop17h67d177ae549d917bE@Base>
    113a:       48 81 c4 00 03 00 00    add    $0x300,%rsp
    1141:       5b                      pop    %rbx
    1142:       c3                      retq   
    1143:       48 89 c3                mov    %rax,%rbx
    1146:       48 8d 7c 24 08          lea    0x8(%rsp),%rdi
    114b:       e8 b0 ff ff ff          callq  1100 <_ZN4core3ptr54drop_in_place$LT$bevy_app..app_builder..AppBuilder$GT$17h76850422c20653deE>
    1150:       48 89 df                mov    %rbx,%rdi
    1153:       e8 18 01 00 00          callq  1270 <_Unwind_Resume@plt>
    1158:       0f 0b                   ud2    
    115a:       cc                      int3   
    115b:       cc                      int3   
    115c:       cc                      int3   
    115d:       cc                      int3   
    115e:       cc                      int3   
    115f:       cc                      int3   

0000000000001160 <main>:
    1160:       48 83 ec 08             sub    $0x8,%rsp
    1164:       48 89 f1                mov    %rsi,%rcx
    1167:       48 63 d7                movslq %edi,%rdx
    116a:       48 8d 05 9f ff ff ff    lea    -0x61(%rip),%rax        # 1110 <_ZN8breakout4main17h7cbe07b319de1042E>
    1171:       48 89 04 24             mov    %rax,(%rsp)
    1175:       48 8d 35 94 1e 00 00    lea    0x1e94(%rip),%rsi        # 3010 <__init_array_end>
    117c:       48 89 e7                mov    %rsp,%rdi
    117f:       ff 15 eb 20 00 00       callq  *0x20eb(%rip)        # 3270 <_ZN3std2rt19lang_start_internal17he77194431b0ee4a2E@Base>
    1185:       59                      pop    %rcx
    1186:       c3                      retq   
    1187:       cc                      int3   
    1188:       cc                      int3   
    1189:       cc                      int3   
    118a:       cc                      int3   
    118b:       cc                      int3   
    118c:       cc                      int3   
    118d:       cc                      int3   
    118e:       cc                      int3   
    118f:       cc                      int3   

0000000000001190 <_ZN3std2rt10lang_start28_$u7b$$u7b$closure$u7d$$u7d$17h83a5b8d55f23dff8E.llvm.909376793398482062>:
    1190:       48 83 ec 08             sub    $0x8,%rsp
    1194:       48 8b 3f                mov    (%rdi),%rdi
    1197:       e8 54 ff ff ff          callq  10f0 <_ZN3std10sys_common9backtrace28__rust_begin_short_backtrace17h6e238af75680eb28E>
    119c:       31 c0                   xor    %eax,%eax
    119e:       59                      pop    %rcx
    119f:       c3                      retq   

00000000000011a0 <_ZN4core3ops8function6FnOnce40call_once$u7b$$u7b$vtable.shim$u7d$$u7d$17hb05d591cd29dea4fE.llvm.909376793398482062>:
    11a0:       48 83 ec 08             sub    $0x8,%rsp
    11a4:       48 8b 3f                mov    (%rdi),%rdi
    11a7:       e8 44 ff ff ff          callq  10f0 <_ZN3std10sys_common9backtrace28__rust_begin_short_backtrace17h6e238af75680eb28E>
    11ac:       31 c0                   xor    %eax,%eax
    11ae:       59                      pop    %rcx
    11af:       c3                      retq   

00000000000011b0 <_ZN4core3ptr85drop_in_place$LT$std..rt..lang_start$LT$$LP$$RP$$GT$..$u7b$$u7b$closure$u7d$$u7d$$GT$17he9aeeba375093b99E.llvm.909376793398482062>:
    11b0:       c3                      retq   
    11b1:       cc                      int3   
    11b2:       cc                      int3   
    11b3:       cc                      int3   
    11b4:       cc                      int3   
    11b5:       cc                      int3   
    11b6:       cc                      int3   
    11b7:       cc                      int3   
    11b8:       cc                      int3   
    11b9:       cc                      int3   
    11ba:       cc                      int3   
    11bb:       cc                      int3   
    11bc:       cc                      int3   
    11bd:       cc                      int3   
    11be:       cc                      int3   
    11bf:       cc                      int3
```

crates/bevy_ecs/src/schedule/mod.rs

@@ -20,6 +20,8 @@ pub use system_container::*;
 pub use system_descriptor::*;
 pub use system_set::*;
 
+use std::fmt::Debug;
+
 use crate::{
  system::{IntoSystem, System},
  world::World,
@@ -144,14 +146,19 @@ impl Schedule {
  stage_label: impl StageLabel,
  system: impl Into<SystemDescriptor>,
  ) -> &mut Self {
+ // Use a function instead of a closure to ensure that it is codegend inside bevy_ecs instead
+ // of the game. Closures inherit generic parameters from their enclosing function.
+ #[cold]
+ fn stage_not_found(stage_label: &dyn Debug) -> ! {
+ panic!(
+ "Stage '{:?}' does not exist or is not a SystemStage",
+ stage_label
+ )
+ }
+
  let stage = self
  .get_stage_mut::<SystemStage>(&stage_label)
- .unwrap_or_else(move || {
- panic!(
- "Stage '{:?}' does not exist or is not a SystemStage",
- stage_label
- )
- });
+ .unwrap_or_else(move || stage_not_found(&stage_label));
  stage.add_system(system);
  self
  }