Auto merge of #143290 - azhogin:azhogin/link-pub-async-impls, r=oli-obk

pub async fn impl is monomorphized when func itself is monomorphized

Implentation coroutine (`func::{closure#0}`) is monomorphized, when func itself is monomorphized.

Currently, when `pub async fn foo(..)` is exported from lib and used in several dependent crates, only 'header' function is monomorphized in the defining crate. 'header' function, returning coroutine object, is monomorphized, but the coroutine's poll function (which actually implements all the logic for the function) is not. In such situation, `func::{closure#0}` will be monomorphized in every dependency.

This PR adds monomorphization for `func::{closure#0}` (coroutine poll function), when func itself is monomorphized.

Simple test with one lib async function and ten dependent crates (executable) that use the function, shows 5-7% compilation time improvement (single-threaded).

3 files changed, 7 insertions, 7 deletions

diff --git a/tests/coverage/async.cov-map b/tests/coverage/async.cov-map
index c528ad525b5..d75c4b5981a 100644
--- a/tests/coverage/async.cov-map
+++ b/tests/coverage/async.cov-map
@@ -103,21 +103,21 @@ Number of file 0 mappings: 3
 Highest counter ID seen: (none)
 
 Function name: async::g
-Raw bytes (9): 0x[01, 01, 00, 01, 01, 1b, 01, 00, 16]
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1b, 01, 00, 12]
 Number of files: 1
 - file 0 => $DIR/async.rs
 Number of expressions: 0
 Number of file 0 mappings: 1
-- Code(Counter(0)) at (prev + 27, 1) to (start + 0, 22)
+- Code(Counter(0)) at (prev + 27, 1) to (start + 0, 18)
 Highest counter ID seen: c0
 
 Function name: async::g::{closure#0} (unused)
-Raw bytes (64): 0x[01, 01, 00, 0c, 00, 1b, 17, 00, 18, 00, 01, 0b, 00, 0c, 00, 01, 09, 00, 0a, 00, 00, 0e, 00, 17, 00, 00, 1b, 00, 1c, 00, 00, 20, 00, 22, 00, 01, 09, 00, 0a, 00, 00, 0e, 00, 17, 00, 00, 1b, 00, 1c, 00, 00, 20, 00, 22, 00, 01, 0e, 00, 10, 00, 02, 01, 00, 02]
+Raw bytes (64): 0x[01, 01, 00, 0c, 00, 1b, 13, 00, 14, 00, 01, 0b, 00, 0c, 00, 01, 09, 00, 0a, 00, 00, 0e, 00, 17, 00, 00, 1b, 00, 1c, 00, 00, 20, 00, 22, 00, 01, 09, 00, 0a, 00, 00, 0e, 00, 17, 00, 00, 1b, 00, 1c, 00, 00, 20, 00, 22, 00, 01, 0e, 00, 10, 00, 02, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/async.rs
 Number of expressions: 0
 Number of file 0 mappings: 12
-- Code(Zero) at (prev + 27, 23) to (start + 0, 24)
+- Code(Zero) at (prev + 27, 19) to (start + 0, 20)
 - Code(Zero) at (prev + 1, 11) to (start + 0, 12)
 - Code(Zero) at (prev + 1, 9) to (start + 0, 10)
 - Code(Zero) at (prev + 0, 14) to (start + 0, 23)
diff --git a/tests/coverage/async.coverage b/tests/coverage/async.coverage
index 9fca1b6997d..9409e6b1deb 100644
--- a/tests/coverage/async.coverage
+++ b/tests/coverage/async.coverage
@@ -24,8 +24,8 @@
    LL|       |
    LL|      0|async fn foo() -> [bool; 10] { [false; 10] } // unused function; executor does not block on `h()`
    LL|       |
-   LL|      1|pub async fn g(x: u8) {
-                                    ^0
+   LL|      1|async fn g(x: u8) {
+                                ^0
    LL|      0|    match x {
    LL|      0|        y if e().await == y => (),
    LL|      0|        y if f().await == y => (),
diff --git a/tests/coverage/async.rs b/tests/coverage/async.rs
index da0a1c0b6f0..777ad7ce7c0 100644
--- a/tests/coverage/async.rs
+++ b/tests/coverage/async.rs
@@ -24,7 +24,7 @@ async fn f() -> u8 { 1 }
 
 async fn foo() -> [bool; 10] { [false; 10] } // unused function; executor does not block on `h()`
 
-pub async fn g(x: u8) {
+async fn g(x: u8) {
     match x {
         y if e().await == y => (),
         y if f().await == y => (),