diff --git a/src/Cargo.lock b/src/Cargo.lock
index d519522a1b0d2..bd37c50157e40 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -996,6 +996,15 @@ name = "itoa"
 version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "jemalloc-sys"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cc 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "jobserver"
 version = "0.1.11"
@@ -2181,6 +2190,7 @@ dependencies = [
  "arena 0.0.0",
  "env_logger 0.5.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "graphviz 0.0.0",
+ "jemalloc-sys 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc-rayon 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3252,6 +3262,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum isatty 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "6c324313540cd4d7ba008d43dc6606a32a5579f13cc17b2804c13096f0a5c522"
 "checksum itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)" = "f58856976b776fedd95533137617a02fb25719f40e7d9b01c7043cd65474f450"
 "checksum itoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "1306f3464951f30e30d12373d31c79fbd52d236e5e896fd92f96ec7babbbe60b"
+"checksum jemalloc-sys 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "479294d130502fada93c7a957e8d059b632b03d6204aca37af557dee947f30a9"
 "checksum jobserver 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)" = "60af5f849e1981434e4a31d3d782c4774ae9b434ce55b101a96ecfd09147e8be"
 "checksum json 0.11.13 (registry+https://github.com/rust-lang/crates.io-index)" = "9ad0485404155f45cce53a40d4b2d6ac356418300daed05273d9e26f91c390be"
 "checksum jsonrpc-core 8.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ddf83704f4e79979a424d1082dd2c1e52683058056c9280efa19ac5f6bc9033c"
diff --git a/src/librustc_driver/Cargo.toml b/src/librustc_driver/Cargo.toml
index 470c8b03d0bca..074a095f7a49c 100644
--- a/src/librustc_driver/Cargo.toml
+++ b/src/librustc_driver/Cargo.toml
@@ -38,3 +38,4 @@ syntax = { path = "../libsyntax" }
 smallvec = { version = "0.6.5", features = ["union"] }
 syntax_ext = { path = "../libsyntax_ext" }
 syntax_pos = { path = "../libsyntax_pos" }
+jemalloc-sys = "*"
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 276b7290c2ef0..2de2473f694be 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -30,6 +30,8 @@
 
 #![recursion_limit="256"]
 
+extern crate jemalloc_sys;
+
 extern crate arena;
 pub extern crate getopts;
 extern crate graphviz;
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index 9ee4582fabf7b..05ca40aa712f7 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -1272,7 +1272,8 @@ impl ToJson for Target {
 
 fn maybe_jemalloc() -> Option<String> {
     if cfg!(feature = "jemalloc") {
-        Some("alloc_jemalloc".to_string())
+        None
+        // Some("alloc_jemalloc".to_string())
     } else {
         None
     }