[do not merge] CI experiments

compiler/rustc/src/main.rs

@@ -39,40 +39,5 @@
 
 fn main() {
     // See the comment at the top of this file for an explanation of this.
-    #[cfg(feature = "jemalloc")]
-    {
-        use std::os::raw::{c_int, c_void};
-
-        use tikv_jemalloc_sys as jemalloc_sys;
-
-        #[used]
-        static _F1: unsafe extern "C" fn(usize, usize) -> *mut c_void = jemalloc_sys::calloc;
-        #[used]
-        static _F2: unsafe extern "C" fn(*mut *mut c_void, usize, usize) -> c_int =
-            jemalloc_sys::posix_memalign;
-        #[used]
-        static _F3: unsafe extern "C" fn(usize, usize) -> *mut c_void = jemalloc_sys::aligned_alloc;
-        #[used]
-        static _F4: unsafe extern "C" fn(usize) -> *mut c_void = jemalloc_sys::malloc;
-        #[used]
-        static _F5: unsafe extern "C" fn(*mut c_void, usize) -> *mut c_void = jemalloc_sys::realloc;
-        #[used]
-        static _F6: unsafe extern "C" fn(*mut c_void) = jemalloc_sys::free;
-
-        // On OSX, jemalloc doesn't directly override malloc/free, but instead
-        // registers itself with the allocator's zone APIs in a ctor. However,
-        // the linker doesn't seem to consider ctors as "used" when statically
-        // linking, so we need to explicitly depend on the function.
-        #[cfg(target_os = "macos")]
-        {
-            unsafe extern "C" {
-                fn _rjem_je_zone_register();
-            }
-
-            #[used]
-            static _F7: unsafe extern "C" fn() = _rjem_je_zone_register;
-        }
-    }
-
     rustc_driver::main()
 }

src/bootstrap/src/core/build_steps/tool.rs

@@ -731,10 +731,7 @@ impl Step for Rustdoc {
         // libraries here. The intuition here is that If we've built a compiler, we should be able
         // to build rustdoc.
         //
-        let mut extra_features = Vec::new();
-        if builder.config.jemalloc(target) {
-            extra_features.push("jemalloc".to_string());
-        }
+        let extra_features = Vec::new();
 
         let ToolBuildResult { tool_path, build_compiler, target_compiler } =
             builder.ensure(ToolBuild {

src/bootstrap/src/lib.rs

@@ -758,9 +758,6 @@ impl Build {
             crates.is_empty() || possible_features_by_crates.contains(feature)
         };
         let mut features = vec![];
-        if self.config.jemalloc(target) && check("jemalloc") {
-            features.push("jemalloc");
-        }
         if (self.config.llvm_enabled(target) || kind == Kind::Check) && check("llvm") {
             features.push("llvm");
         }