Change -Copt-level=3 to -Copt-level=2

Author: Kobzol

compiler/rustc_session/src/config.rs

@@ -2096,7 +2096,7 @@ fn parse_opt_level(
             if let Some("opt-level") = s.split('=').next() { Some(i) } else { None }
         })
         .max();
-    if max_o > max_c {
+    let level = if max_o > max_c {
         OptLevel::Default
     } else {
         match cg.opt_level.as_ref() {
@@ -2113,6 +2113,11 @@ fn parse_opt_level(
                 ));
             }
         }
+    };
+    if std::env::var("BOOTSTRAPPIN").is_err() && level == OptLevel::Aggressive {
+        OptLevel::Default
+    } else {
+        level
     }
 }
 

src/bootstrap/src/core/builder/cargo.rs

@@ -110,6 +110,7 @@ impl Cargo {
         cmd_kind: Kind,
     ) -> Cargo {
         let mut cargo = builder.cargo(compiler, mode, source_type, target, cmd_kind);
+        cargo.env("BOOTSTRAPPIN", "1");
 
         match cmd_kind {
             // No need to configure the target linker for these command types,