From ab6fb9d2aa440a48723d311bcd065be9552a27f0 Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Thu, 14 Jul 2022 10:03:08 +0000
Subject: [PATCH] Allow tests to have dependencies

---
 Cargo.lock                                    |  35 ++
 cargo-miri/bin.rs                             |  62 ++-
 test-cargo-miri/Cargo.lock                    |  23 +-
 test-cargo-miri/Cargo.toml                    |   2 -
 test-cargo-miri/run-test.py                   |  28 +-
 test-cargo-miri/tests/test.rs                 |   8 +-
 test_dependencies/Cargo.lock                  | 376 ++++++++++++++++++
 test_dependencies/Cargo.toml                  |  19 +
 test_dependencies/src/main.rs                 |   1 +
 tests/compiletest.rs                          |  49 ++-
 .../libc_pthread_create_main_terminate.rs     |   2 -
 .../concurrency/libc_pthread_join_detached.rs |   2 -
 .../concurrency/libc_pthread_join_joined.rs   |   2 -
 .../concurrency/libc_pthread_join_main.rs     |   2 -
 .../concurrency/libc_pthread_join_multiple.rs |   2 -
 .../concurrency/libc_pthread_join_self.rs     |   2 -
 tests/fail/concurrency/too_few_args.rs        |   2 -
 tests/fail/concurrency/too_many_args.rs       |   2 -
 tests/fail/concurrency/unwind_top_of_stack.rs |   2 -
 tests/fail/fs/close_stdout.rs                 |   2 -
 tests/fail/fs/isolated_stdin.rs               |   2 -
 tests/fail/fs/read_from_stdout.rs             |   2 -
 .../fs/unix_open_missing_required_mode.rs     |   2 -
 tests/fail/fs/write_to_stdin.rs               |   2 -
 .../sync/libc_pthread_cond_double_destroy.rs  |   1 -
 .../libc_pthread_condattr_double_destroy.rs   |   1 -
 .../sync/libc_pthread_mutex_NULL_deadlock.rs  |   2 -
 .../fail/sync/libc_pthread_mutex_deadlock.rs  |   2 -
 .../libc_pthread_mutex_default_deadlock.rs    |   2 -
 .../sync/libc_pthread_mutex_destroy_locked.rs |   2 -
 .../sync/libc_pthread_mutex_double_destroy.rs |   1 -
 .../libc_pthread_mutex_normal_deadlock.rs     |   2 -
 ...bc_pthread_mutex_normal_unlock_unlocked.rs |   2 -
 .../sync/libc_pthread_mutex_wrong_owner.rs    |   2 -
 .../libc_pthread_mutexattr_double_destroy.rs  |   1 -
 ...libc_pthread_rwlock_destroy_read_locked.rs |   2 -
 ...ibc_pthread_rwlock_destroy_write_locked.rs |   2 -
 .../libc_pthread_rwlock_double_destroy.rs     |   1 -
 ...wlock_read_write_deadlock_single_thread.rs |   2 -
 .../libc_pthread_rwlock_read_wrong_owner.rs   |   2 -
 .../libc_pthread_rwlock_unlock_unlocked.rs    |   2 -
 ...libc_pthread_rwlock_write_read_deadlock.rs |   2 -
 ...wlock_write_read_deadlock_single_thread.rs |   2 -
 ...ibc_pthread_rwlock_write_write_deadlock.rs |   2 -
 ...lock_write_write_deadlock_single_thread.rs |   2 -
 .../libc_pthread_rwlock_write_wrong_owner.rs  |   2 -
 tests/fail/tokio_mvp.rs                       |   7 +
 tests/fail/tokio_mvp.stderr                   |  19 +
 tests/fail/unsupported_signal.rs              |   2 -
 tests/panic/panic/unsupported_syscall.rs      |   2 -
 tests/pass/calloc.rs                          |   2 -
 tests/pass/concurrency/libc_pthread_cond.rs   |   2 -
 tests/pass/concurrency/linux-futex.rs         |   1 -
 .../concurrency/tls_pthread_drop_order.rs     |   1 -
 tests/pass/foreign-fn-linkname.rs             |   2 -
 tests/pass/fs.rs                              |   2 -
 tests/pass/fs_with_isolation.rs               |   2 -
 tests/pass/libc.rs                            |   2 -
 .../pass/linux-getrandom-without-isolation.rs |   1 -
 tests/pass/linux-getrandom.rs                 |   1 -
 tests/pass/malloc.rs                          |   2 -
 tests/pass/random.rs                          |  22 +
 tests/pass/regions-mock-trans.rs              |   2 -
 ui_test/Cargo.lock                            |  35 ++
 ui_test/Cargo.toml                            |   2 +-
 ui_test/README.md                             |   2 +
 ui_test/src/dependencies.rs                   | 137 +++++++
 ui_test/src/lib.rs                            |  37 +-
 ui_test/src/tests.rs                          |   2 +
 69 files changed, 792 insertions(+), 165 deletions(-)
 create mode 100644 test_dependencies/Cargo.lock
 create mode 100644 test_dependencies/Cargo.toml
 create mode 100644 test_dependencies/src/main.rs
 create mode 100644 tests/fail/tokio_mvp.rs
 create mode 100644 tests/fail/tokio_mvp.stderr
 create mode 100644 tests/pass/random.rs
 create mode 100644 ui_test/src/dependencies.rs

diff --git a/Cargo.lock b/Cargo.lock
index cc707c630e..f660ed7762 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -73,6 +73,37 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "camino"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "869119e97797867fd90f5e22af7d0bd274bd4635ebb9eb68c04f3f513ae6c412"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "cargo-platform"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cbdb825da8a5df079a43676dbe042702f1707b1109f713a01420fbb4cc71fa27"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "cargo_metadata"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3abb7553d5b9b8421c6de7cb02606ff15e0c6eea7d8eadd75ef013fd636bec36"
+dependencies = [
+ "camino",
+ "cargo-platform",
+ "semver",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "cc"
 version = "1.0.73"
@@ -596,6 +627,9 @@ name = "semver"
 version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8cb243bdfdb5936c8dc3c45762a19d12ab4550cdc753bc247637d4ec35a040fd"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "serde"
@@ -724,6 +758,7 @@ dependencies = [
 name = "ui_test"
 version = "0.1.0"
 dependencies = [
+ "cargo_metadata",
  "color-eyre",
  "colored",
  "crossbeam",
diff --git a/cargo-miri/bin.rs b/cargo-miri/bin.rs
index 2ab854b906..6e140ab714 100644
--- a/cargo-miri/bin.rs
+++ b/cargo-miri/bin.rs
@@ -3,6 +3,7 @@
 
 mod version;
 
+use std::collections::HashMap;
 use std::env;
 use std::ffi::{OsStr, OsString};
 use std::fmt::Write as _;
@@ -114,10 +115,14 @@ fn show_error(msg: String) -> ! {
     std::process::exit(1)
 }
 
-// Determines whether a `--flag` is present.
+/// Determines whether a `--flag` is present.
 fn has_arg_flag(name: &str) -> bool {
-    let mut args = std::env::args().take_while(|val| val != "--");
-    args.any(|val| val == name)
+    num_arg_flag(name) > 0
+}
+
+/// Determines how many times a `--flag` is present.
+fn num_arg_flag(name: &str) -> usize {
+    std::env::args().take_while(|val| val != "--").filter(|val| val == name).count()
 }
 
 /// Yields all values of command line flag `name` as `Ok(arg)`, and all other arguments except
@@ -588,7 +593,7 @@ fn phase_cargo_miri(mut args: env::Args) {
                 "`cargo miri` supports the following subcommands: `run`, `test`, and `setup`."
             )),
     };
-    let verbose = has_arg_flag("-v");
+    let verbose = num_arg_flag("-v");
 
     // We always setup.
     setup(&subcommand);
@@ -685,7 +690,7 @@ fn phase_cargo_miri(mut args: env::Args) {
     cmd.env("MIRI_LOCAL_CRATES", local_crates(&metadata));
 
     // Run cargo.
-    if verbose {
+    if verbose > 0 {
         eprintln!("[cargo-miri miri] RUSTC_WRAPPER={:?}", cargo_miri_path);
         eprintln!("[cargo-miri miri] {}={:?}", target_runner_env_name, cargo_miri_path);
         if *target != host {
@@ -693,7 +698,7 @@ fn phase_cargo_miri(mut args: env::Args) {
         }
         eprintln!("[cargo-miri miri] RUSTDOC={:?}", cargo_miri_path);
         eprintln!("[cargo-miri miri] {:?}", cmd);
-        cmd.env("MIRI_VERBOSE", ""); // This makes the other phases verbose.
+        cmd.env("MIRI_VERBOSE", verbose.to_string()); // This makes the other phases verbose.
     }
     exec(cmd)
 }
@@ -752,7 +757,8 @@ fn phase_rustc(mut args: env::Args, phase: RustcPhase) {
         }
     }
 
-    let verbose = std::env::var_os("MIRI_VERBOSE").is_some();
+    let verbose = std::env::var("MIRI_VERBOSE")
+        .map_or(0, |verbose| verbose.parse().expect("verbosity flag must be an integer"));
     let target_crate = is_target_crate();
     let print = get_arg_flag_value("--print").is_some() || has_arg_flag("-vV"); // whether this is cargo/xargo invoking rustc to get some infos
 
@@ -761,13 +767,13 @@ fn phase_rustc(mut args: env::Args, phase: RustcPhase) {
         // https://github.com/rust-lang/miri/issues/1724#issuecomment-787115693
         // As we store a JSON file instead of building the crate here, an empty file is fine.
         let dep_info_name = out_filename("", ".d");
-        if verbose {
+        if verbose > 0 {
             eprintln!("[cargo-miri rustc] writing stub dep-info to `{}`", dep_info_name.display());
         }
         File::create(dep_info_name).expect("failed to create fake .d file");
 
         let filename = out_filename("", "");
-        if verbose {
+        if verbose > 0 {
             eprintln!("[cargo-miri rustc] writing run info to `{}`", filename.display());
         }
         info.store(&filename);
@@ -810,7 +816,7 @@ fn phase_rustc(mut args: env::Args, phase: RustcPhase) {
             cmd.args(&env.args);
             cmd.env("MIRI_BE_RUSTC", "target");
 
-            if verbose {
+            if verbose > 0 {
                 eprintln!(
                     "[cargo-miri rustc] captured input:\n{}",
                     std::str::from_utf8(&env.stdin).unwrap()
@@ -877,6 +883,15 @@ fn phase_rustc(mut args: env::Args, phase: RustcPhase) {
             cmd.arg("-C").arg("panic=abort");
         }
     } else {
+        // For host crates (but not when we are printing), we might still have to set the sysroot.
+        if !print {
+            // When we're running `cargo-miri` from `x.py` we need to pass the sysroot explicitly as rustc
+            // can't figure out the sysroot on its own unless it's from rustup.
+            if let Some(sysroot) = std::env::var_os("SYSROOT") {
+                cmd.arg("--sysroot").arg(sysroot);
+            }
+        }
+
         // For host crates or when we are printing, just forward everything.
         cmd.args(args);
     }
@@ -888,8 +903,14 @@ fn phase_rustc(mut args: env::Args, phase: RustcPhase) {
     cmd.env("MIRI_BE_RUSTC", if target_crate { "target" } else { "host" });
 
     // Run it.
-    if verbose {
-        eprintln!("[cargo-miri rustc] {:?}", cmd);
+    if verbose > 0 {
+        eprint!("[cargo-miri rustc] ");
+        if verbose > 1 {
+            for (key, value) in env_vars_from_cmd(&cmd) {
+                eprintln!("{key}={value:?} \\");
+            }
+        }
+        eprintln!("{:?}", cmd);
     }
     exec(cmd);
 
@@ -908,6 +929,23 @@ fn phase_rustc(mut args: env::Args, phase: RustcPhase) {
     }
 }
 
+fn env_vars_from_cmd(cmd: &Command) -> Vec<(String, String)> {
+    let mut envs = HashMap::new();
+    for (key, value) in std::env::vars() {
+        envs.insert(key, value);
+    }
+    for (key, value) in cmd.get_envs() {
+        if let Some(value) = value {
+            envs.insert(key.to_str().unwrap().into(), value.to_str().unwrap().to_owned());
+        } else {
+            envs.remove(key.to_str().unwrap());
+        }
+    }
+    let mut envs: Vec<_> = envs.into_iter().collect();
+    envs.sort();
+    envs
+}
+
 #[derive(Debug, Copy, Clone, PartialEq)]
 enum RunnerPhase {
     /// `cargo` is running a binary
diff --git a/test-cargo-miri/Cargo.lock b/test-cargo-miri/Cargo.lock
index d34db9f14d..4cf58d723a 100644
--- a/test-cargo-miri/Cargo.lock
+++ b/test-cargo-miri/Cargo.lock
@@ -15,8 +15,6 @@ dependencies = [
  "byteorder",
  "cdylib",
  "exported_symbol",
- "getrandom 0.1.16",
- "getrandom 0.2.7",
  "issue_1567",
  "issue_1691",
  "issue_1705",
@@ -51,17 +49,6 @@ dependencies = [
 name = "exported_symbol_dep"
 version = "0.1.0"
 
-[[package]]
-name = "getrandom"
-version = "0.1.16"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
-dependencies = [
- "cfg-if",
- "libc",
- "wasi 0.9.0+wasi-snapshot-preview1",
-]
-
 [[package]]
 name = "getrandom"
 version = "0.2.7"
@@ -70,7 +57,7 @@ checksum = "4eb1a864a501629691edf6c15a593b7a51eebaa1e8468e9ddc623de7c9b58ec6"
 dependencies = [
  "cfg-if",
  "libc",
- "wasi 0.11.0+wasi-snapshot-preview1",
+ "wasi",
 ]
 
 [[package]]
@@ -185,7 +172,7 @@ version = "0.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
 dependencies = [
- "getrandom 0.2.7",
+ "getrandom",
 ]
 
 [[package]]
@@ -223,12 +210,6 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5bd2fe26506023ed7b5e1e315add59d6f584c621d037f9368fea9cfb988f368c"
 
-[[package]]
-name = "wasi"
-version = "0.9.0+wasi-snapshot-preview1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
-
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
diff --git a/test-cargo-miri/Cargo.toml b/test-cargo-miri/Cargo.toml
index 2193d354d5..89a8463e4b 100644
--- a/test-cargo-miri/Cargo.toml
+++ b/test-cargo-miri/Cargo.toml
@@ -19,8 +19,6 @@ issue_rust_86261 = { path = "issue-rust-86261" }
 
 [dev-dependencies]
 rand = { version = "0.8", features = ["small_rng"] }
-getrandom_1 = { package = "getrandom", version = "0.1" }
-getrandom_2 = { package = "getrandom", version = "0.2" }
 serde_derive = "1.0" # not actually used, but exercises some unique code path (`--extern` .so file)
 page_size = "0.4.1"
 
diff --git a/test-cargo-miri/run-test.py b/test-cargo-miri/run-test.py
index 09e7df39b1..bc0046ffb1 100755
--- a/test-cargo-miri/run-test.py
+++ b/test-cargo-miri/run-test.py
@@ -5,7 +5,7 @@
 and the working directory to contain the cargo-miri-test project.
 '''
 
-import sys, subprocess, os, re
+import sys, subprocess, os, re, difflib
 
 CGREEN  = '\33[32m'
 CBOLD   = '\33[1m'
@@ -27,6 +27,17 @@ def normalize_stdout(str):
     str = str.replace("src\\", "src/") # normalize paths across platforms
     return re.sub("finished in \d+\.\d\ds", "finished in $TIME", str)
 
+def check_output(actual, path, name):
+    expected = open(path).read()
+    if expected == actual:
+        return True
+    print(f"{path} did not match reference!")
+    print(f"--- BEGIN diff {name} ---")
+    for text in difflib.unified_diff(expected.split("\n"), actual.split("\n")):
+        print(text)
+    print(f"--- END diff {name} ---")
+    return False
+
 def test(name, cmd, stdout_ref, stderr_ref, stdin=b'', env={}):
     print("Testing {}...".format(name))
     ## Call `cargo miri`, capture all output
@@ -42,17 +53,14 @@ def test(name, cmd, stdout_ref, stderr_ref, stdin=b'', env={}):
     (stdout, stderr) = p.communicate(input=stdin)
     stdout = stdout.decode("UTF-8")
     stderr = stderr.decode("UTF-8")
-    if p.returncode == 0 and normalize_stdout(stdout) == open(stdout_ref).read() and stderr == open(stderr_ref).read():
+    stdout = normalize_stdout(stdout)
+
+    stdout_matches = check_output(stdout, stdout_ref, "stdout")
+    stderr_matches = check_output(stderr, stderr_ref, "stderr")
+    
+    if p.returncode == 0 and stdout_matches and stderr_matches:
         # All good!
         return
-    # Show output
-    print("Test stdout or stderr did not match reference!")
-    print("--- BEGIN test stdout ---")
-    print(stdout, end="")
-    print("--- END test stdout ---")
-    print("--- BEGIN test stderr ---")
-    print(stderr, end="")
-    print("--- END test stderr ---")
     fail("exit code was {}".format(p.returncode))
 
 def test_no_rebuild(name, cmd, env={}):
diff --git a/test-cargo-miri/tests/test.rs b/test-cargo-miri/tests/test.rs
index 8a938ef3c2..eb31058e1c 100644
--- a/test-cargo-miri/tests/test.rs
+++ b/test-cargo-miri/tests/test.rs
@@ -20,15 +20,9 @@ fn does_not_work_on_miri() {
     assert!(&x as *const _ as usize % 4 < 4);
 }
 
-// We also use this to test some external crates, that we cannot depend on in the compiletest suite.
-
+// Make sure integration tests can access dev-dependencies
 #[test]
 fn entropy_rng() {
-    // Test `getrandom` directly (in multiple different versions).
-    let mut data = vec![0; 16];
-    getrandom_1::getrandom(&mut data).unwrap();
-    getrandom_2::getrandom(&mut data).unwrap();
-
     // Try seeding with "real" entropy.
     let mut rng = SmallRng::from_entropy();
     let _val = rng.gen::<i32>();
diff --git a/test_dependencies/Cargo.lock b/test_dependencies/Cargo.lock
new file mode 100644
index 0000000000..6b5e8c9422
--- /dev/null
+++ b/test_dependencies/Cargo.lock
@@ -0,0 +1,376 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "autocfg"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
+[[package]]
+name = "bytes"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4872d67bab6358e59559027aa3b9157c53d9358c51423c17554809a8858e0f8"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "getrandom"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi 0.9.0+wasi-snapshot-preview1",
+]
+
+[[package]]
+name = "getrandom"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4eb1a864a501629691edf6c15a593b7a51eebaa1e8468e9ddc623de7c9b58ec6"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi 0.11.0+wasi-snapshot-preview1",
+]
+
+[[package]]
+name = "hermit-abi"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.126"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "349d5a591cd28b49e1d1037471617a32ddcda5731b99419008085f72d5a53836"
+
+[[package]]
+name = "lock_api"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "327fa5b6a6940e4699ec49a9beae1ea4845c6bab9314e4f84ac68742139d8c53"
+dependencies = [
+ "autocfg",
+ "scopeguard",
+]
+
+[[package]]
+name = "log"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "memchr"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
+
+[[package]]
+name = "mio"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57ee1c23c7c63b0c9250c339ffdc69255f110b298b901b9f6c82547b7b87caaf"
+dependencies = [
+ "libc",
+ "log",
+ "wasi 0.11.0+wasi-snapshot-preview1",
+ "windows-sys",
+]
+
+[[package]]
+name = "miri-test-deps"
+version = "0.1.0"
+dependencies = [
+ "getrandom 0.1.16",
+ "getrandom 0.2.7",
+ "libc",
+ "rand",
+ "tokio",
+]
+
+[[package]]
+name = "num_cpus"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19e64526ebdee182341572e50e9ad03965aa510cd94427a4549448f285e957a1"
+dependencies = [
+ "hermit-abi",
+ "libc",
+]
+
+[[package]]
+name = "once_cell"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18a6dbe30758c9f83eb00cbea4ac95966305f5a7772f3f42ebfc7fc7eddbd8e1"
+
+[[package]]
+name = "parking_lot"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3742b2c103b9f06bc9fff0a37ff4912935851bee6d36f3c02bcc755bcfec228f"
+dependencies = [
+ "lock_api",
+ "parking_lot_core",
+]
+
+[[package]]
+name = "parking_lot_core"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09a279cbf25cb0757810394fbc1e359949b59e348145c643a939a525692e6929"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "redox_syscall",
+ "smallvec",
+ "windows-sys",
+]
+
+[[package]]
+name = "pin-project-lite"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e0a7ae3ac2f1173085d398531c705756c94a4c56843785df85a60c1a0afac116"
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd96a1e8ed2596c337f8eae5f24924ec83f5ad5ab21ea8e455d3566c69fbcaf7"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3bcdf212e9776fbcb2d23ab029360416bb1706b1aea2d1a5ba002727cbcab804"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
+dependencies = [
+ "getrandom 0.2.7",
+]
+
+[[package]]
+name = "redox_syscall"
+version = "0.2.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62f25bc4c7e55e0b0b7a1d43fb893f4fa1361d0abe38b9ce4f323c2adfe6ef42"
+dependencies = [
+ "bitflags",
+]
+
+[[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
+[[package]]
+name = "signal-hook-registry"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e51e73328dc4ac0c7ccbda3a494dfa03df1de2f46018127f60c693f2648455b0"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "smallvec"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fd0db749597d91ff862fd1d55ea87f7855a744a8425a64695b6fca237d1dad1"
+
+[[package]]
+name = "socket2"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "66d72b759436ae32898a2af0a14218dbf55efde3feeb170eb623637db85ee1e0"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.98"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c50aef8a904de4c23c788f104b7dddc7d6f79c647c7c8ce4cc8f73eb0ca773dd"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "tokio"
+version = "1.19.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c51a52ed6686dd62c320f9b89299e9dfb46f730c7a48e635c19f21d116cb1439"
+dependencies = [
+ "bytes",
+ "libc",
+ "memchr",
+ "mio",
+ "num_cpus",
+ "once_cell",
+ "parking_lot",
+ "pin-project-lite",
+ "signal-hook-registry",
+ "socket2",
+ "tokio-macros",
+ "winapi",
+]
+
+[[package]]
+name = "tokio-macros"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9724f9a975fb987ef7a3cd9be0350edcbe130698af5b8f7a631e23d42d052484"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5bd2fe26506023ed7b5e1e315add59d6f584c621d037f9368fea9cfb988f368c"
+
+[[package]]
+name = "wasi"
+version = "0.9.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
+
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "windows-sys"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea04155a16a59f9eab786fe12a4a450e75cdb175f9e0d80da1e17db09f55b8d2"
+dependencies = [
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9bb8c3fd39ade2d67e9874ac4f3db21f0d710bee00fe7cab16949ec184eeaa47"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "180e6ccf01daf4c426b846dfc66db1fc518f074baa793aa7d9b9aaeffad6a3b6"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2e7917148b2812d1eeafaeb22a97e4813dfa60a3f8f78ebe204bcc88f12f024"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4dcd171b8776c41b97521e5da127a2d86ad280114807d0b2ab1e462bc764d9e1"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c811ca4a8c853ef420abd8592ba53ddbbac90410fab6903b3e79972a631f7680"
diff --git a/test_dependencies/Cargo.toml b/test_dependencies/Cargo.toml
new file mode 100644
index 0000000000..edaa6a6926
--- /dev/null
+++ b/test_dependencies/Cargo.toml
@@ -0,0 +1,19 @@
+[package]
+authors = ["Miri Team"]
+description = "dependencies that unit tests can have"
+license = "MIT OR Apache-2.0"
+name = "miri-test-deps"
+repository = "https://github.com/rust-lang/miri"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+# all dependencies (and their transitive ones) listed here can be used in `tests/`.
+tokio = { version = "1.0", features = ["full"] }
+libc = "0.2"
+
+getrandom_1 = { package = "getrandom", version = "0.1" }
+getrandom_2 = { package = "getrandom", version = "0.2" }
+rand = { version = "0.8", features = ["small_rng"] }
+
+[workspace]
diff --git a/test_dependencies/src/main.rs b/test_dependencies/src/main.rs
new file mode 100644
index 0000000000..f328e4d9d0
--- /dev/null
+++ b/test_dependencies/src/main.rs
@@ -0,0 +1 @@
+fn main() {}
diff --git a/tests/compiletest.rs b/tests/compiletest.rs
index ec49e80ca9..37b9de7327 100644
--- a/tests/compiletest.rs
+++ b/tests/compiletest.rs
@@ -1,8 +1,8 @@
 use colored::*;
 use regex::Regex;
-use std::env;
-use std::path::PathBuf;
-use ui_test::{color_eyre::Result, Config, Mode, OutputConflictHandling};
+use std::path::{Path, PathBuf};
+use std::{env, ffi::OsString};
+use ui_test::{color_eyre::Result, Config, DependencyBuilder, Mode, OutputConflictHandling};
 
 fn miri_path() -> PathBuf {
     PathBuf::from(option_env!("MIRI").unwrap_or(env!("CARGO_BIN_EXE_miri")))
@@ -12,31 +12,31 @@ fn run_tests(mode: Mode, path: &str, target: Option<String>) -> Result<()> {
     let in_rustc_test_suite = option_env!("RUSTC_STAGE").is_some();
 
     // Add some flags we always want.
-    let mut flags = Vec::new();
-    flags.push("--edition".to_owned());
-    flags.push("2018".to_owned());
+    let mut flags: Vec<OsString> = Vec::new();
+    flags.push("--edition".into());
+    flags.push("2018".into());
     if in_rustc_test_suite {
         // Less aggressive warnings to make the rustc toolstate management less painful.
         // (We often get warnings when e.g. a feature gets stabilized or some lint gets added/improved.)
-        flags.push("-Astable-features".to_owned());
-        flags.push("-Aunused".to_owned());
+        flags.push("-Astable-features".into());
+        flags.push("-Aunused".into());
     } else {
-        flags.push("-Dwarnings".to_owned());
-        flags.push("-Dunused".to_owned());
+        flags.push("-Dwarnings".into());
+        flags.push("-Dunused".into());
     }
-    if let Ok(sysroot) = env::var("MIRI_SYSROOT") {
-        flags.push("--sysroot".to_string());
+    if let Some(sysroot) = env::var_os("MIRI_SYSROOT") {
+        flags.push("--sysroot".into());
         flags.push(sysroot);
     }
     if let Ok(extra_flags) = env::var("MIRIFLAGS") {
         for flag in extra_flags.split_whitespace() {
-            flags.push(flag.to_string());
+            flags.push(flag.into());
         }
     }
-    flags.push("-Zui-testing".to_string());
+    flags.push("-Zui-testing".into());
     if let Some(target) = &target {
-        flags.push("--target".to_string());
-        flags.push(target.clone());
+        flags.push("--target".into());
+        flags.push(target.into());
     }
 
     let skip_ui_checks = env::var_os("MIRI_SKIP_UI_CHECKS").is_some();
@@ -51,6 +51,8 @@ fn run_tests(mode: Mode, path: &str, target: Option<String>) -> Result<()> {
     // Pass on all arguments as filters.
     let path_filter = std::env::args().skip(1);
 
+    let use_std = env::var_os("MIRI_NO_STD").is_none();
+
     let config = Config {
         args: flags,
         target,
@@ -61,6 +63,19 @@ fn run_tests(mode: Mode, path: &str, target: Option<String>) -> Result<()> {
         path_filter: path_filter.collect(),
         program: miri_path(),
         output_conflict_handling,
+        dependencies_crate_manifest_path: use_std
+            .then(|| Path::new("test_dependencies").join("Cargo.toml")),
+        dependency_builder: Some(DependencyBuilder {
+            program: std::env::var_os("CARGO").unwrap().into(),
+            args: vec![
+                "run".into(),
+                "--manifest-path".into(),
+                "cargo-miri/Cargo.toml".into(),
+                "--".into(),
+                "miri".into(),
+            ],
+            envs: vec![],
+        }),
     };
     ui_test::run_tests(config)
 }
@@ -107,6 +122,8 @@ regexes! {
     "[^ `]*/(rust[^/]*|checkout)/library/" => "RUSTLIB/",
     // erase platform file paths
     "sys/[a-z]+/"                    => "sys/PLATFORM/",
+    // erase paths into the crate registry
+    r"[^ ]*/\.cargo/registry/.*/(.*\.rs)"  => "CARGO_REGISTRY/$1",
 }
 
 fn ui(mode: Mode, path: &str) -> Result<()> {
diff --git a/tests/fail/concurrency/libc_pthread_create_main_terminate.rs b/tests/fail/concurrency/libc_pthread_create_main_terminate.rs
index 169a021215..9da9fbf202 100644
--- a/tests/fail/concurrency/libc_pthread_create_main_terminate.rs
+++ b/tests/fail/concurrency/libc_pthread_create_main_terminate.rs
@@ -5,8 +5,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::{mem, ptr};
 
 extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
diff --git a/tests/fail/concurrency/libc_pthread_join_detached.rs b/tests/fail/concurrency/libc_pthread_join_detached.rs
index 6f0d45e2dc..e81978fc99 100644
--- a/tests/fail/concurrency/libc_pthread_join_detached.rs
+++ b/tests/fail/concurrency/libc_pthread_join_detached.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::{mem, ptr};
 
 extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
diff --git a/tests/fail/concurrency/libc_pthread_join_joined.rs b/tests/fail/concurrency/libc_pthread_join_joined.rs
index 77f59fabca..11e00429c6 100644
--- a/tests/fail/concurrency/libc_pthread_join_joined.rs
+++ b/tests/fail/concurrency/libc_pthread_join_joined.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::{mem, ptr};
 
 extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
diff --git a/tests/fail/concurrency/libc_pthread_join_main.rs b/tests/fail/concurrency/libc_pthread_join_main.rs
index aff28bcc9b..f029f08772 100644
--- a/tests/fail/concurrency/libc_pthread_join_main.rs
+++ b/tests/fail/concurrency/libc_pthread_join_main.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::{ptr, thread};
 
 fn main() {
diff --git a/tests/fail/concurrency/libc_pthread_join_multiple.rs b/tests/fail/concurrency/libc_pthread_join_multiple.rs
index d4d54d3a23..017036ab01 100644
--- a/tests/fail/concurrency/libc_pthread_join_multiple.rs
+++ b/tests/fail/concurrency/libc_pthread_join_multiple.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::thread;
 use std::{mem, ptr};
 
diff --git a/tests/fail/concurrency/libc_pthread_join_self.rs b/tests/fail/concurrency/libc_pthread_join_self.rs
index b911b2db3a..ae61488931 100644
--- a/tests/fail/concurrency/libc_pthread_join_self.rs
+++ b/tests/fail/concurrency/libc_pthread_join_self.rs
@@ -6,8 +6,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::{ptr, thread};
 
 fn main() {
diff --git a/tests/fail/concurrency/too_few_args.rs b/tests/fail/concurrency/too_few_args.rs
index 11e97ca290..4760fbb6b0 100644
--- a/tests/fail/concurrency/too_few_args.rs
+++ b/tests/fail/concurrency/too_few_args.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::{mem, ptr};
 
 extern "C" fn thread_start() -> *mut libc::c_void {
diff --git a/tests/fail/concurrency/too_many_args.rs b/tests/fail/concurrency/too_many_args.rs
index dd44207a62..6abe767dc8 100644
--- a/tests/fail/concurrency/too_many_args.rs
+++ b/tests/fail/concurrency/too_many_args.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::{mem, ptr};
 
 extern "C" fn thread_start(_null: *mut libc::c_void, _x: i32) -> *mut libc::c_void {
diff --git a/tests/fail/concurrency/unwind_top_of_stack.rs b/tests/fail/concurrency/unwind_top_of_stack.rs
index 179ff9c146..bd49401e61 100644
--- a/tests/fail/concurrency/unwind_top_of_stack.rs
+++ b/tests/fail/concurrency/unwind_top_of_stack.rs
@@ -5,8 +5,6 @@
 
 #![feature(rustc_private, c_unwind)]
 
-extern crate libc;
-
 use std::{mem, ptr};
 
 extern "C-unwind" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
diff --git a/tests/fail/fs/close_stdout.rs b/tests/fail/fs/close_stdout.rs
index bc709fe36d..86a6239f5f 100644
--- a/tests/fail/fs/close_stdout.rs
+++ b/tests/fail/fs/close_stdout.rs
@@ -5,8 +5,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     unsafe {
         libc::close(1); //~ ERROR: stdout cannot be closed
diff --git a/tests/fail/fs/isolated_stdin.rs b/tests/fail/fs/isolated_stdin.rs
index cd54de3bce..86b04a0383 100644
--- a/tests/fail/fs/isolated_stdin.rs
+++ b/tests/fail/fs/isolated_stdin.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() -> std::io::Result<()> {
     let mut bytes = [0u8; 512];
     unsafe {
diff --git a/tests/fail/fs/read_from_stdout.rs b/tests/fail/fs/read_from_stdout.rs
index 949fe88f43..0fd8ba2fc4 100644
--- a/tests/fail/fs/read_from_stdout.rs
+++ b/tests/fail/fs/read_from_stdout.rs
@@ -3,8 +3,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() -> std::io::Result<()> {
     let mut bytes = [0u8; 512];
     unsafe {
diff --git a/tests/fail/fs/unix_open_missing_required_mode.rs b/tests/fail/fs/unix_open_missing_required_mode.rs
index 1f6beadcb8..4740dcebe9 100644
--- a/tests/fail/fs/unix_open_missing_required_mode.rs
+++ b/tests/fail/fs/unix_open_missing_required_mode.rs
@@ -3,8 +3,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     test_file_open_missing_needed_mode();
 }
diff --git a/tests/fail/fs/write_to_stdin.rs b/tests/fail/fs/write_to_stdin.rs
index 4ad7b648e1..0e9109fc6e 100644
--- a/tests/fail/fs/write_to_stdin.rs
+++ b/tests/fail/fs/write_to_stdin.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() -> std::io::Result<()> {
     let bytes = b"hello";
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_cond_double_destroy.rs b/tests/fail/sync/libc_pthread_cond_double_destroy.rs
index d0a4ac46cb..90d5997f87 100644
--- a/tests/fail/sync/libc_pthread_cond_double_destroy.rs
+++ b/tests/fail/sync/libc_pthread_cond_double_destroy.rs
@@ -2,7 +2,6 @@
 #![feature(rustc_private)]
 
 /// Test that destroying a pthread_cond twice fails, even without a check for number validity
-extern crate libc;
 
 fn main() {
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_condattr_double_destroy.rs b/tests/fail/sync/libc_pthread_condattr_double_destroy.rs
index c64b323813..028a924196 100644
--- a/tests/fail/sync/libc_pthread_condattr_double_destroy.rs
+++ b/tests/fail/sync/libc_pthread_condattr_double_destroy.rs
@@ -2,7 +2,6 @@
 #![feature(rustc_private)]
 
 /// Test that destroying a pthread_condattr twice fails, even without a check for number validity
-extern crate libc;
 
 fn main() {
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_mutex_NULL_deadlock.rs b/tests/fail/sync/libc_pthread_mutex_NULL_deadlock.rs
index 8797e895d8..d87455877a 100644
--- a/tests/fail/sync/libc_pthread_mutex_NULL_deadlock.rs
+++ b/tests/fail/sync/libc_pthread_mutex_NULL_deadlock.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     unsafe {
         let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
diff --git a/tests/fail/sync/libc_pthread_mutex_deadlock.rs b/tests/fail/sync/libc_pthread_mutex_deadlock.rs
index 7da6e51600..f77f5c2e20 100644
--- a/tests/fail/sync/libc_pthread_mutex_deadlock.rs
+++ b/tests/fail/sync/libc_pthread_mutex_deadlock.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::cell::UnsafeCell;
 use std::sync::Arc;
 use std::thread;
diff --git a/tests/fail/sync/libc_pthread_mutex_default_deadlock.rs b/tests/fail/sync/libc_pthread_mutex_default_deadlock.rs
index 70a85aa0f9..b28101e20b 100644
--- a/tests/fail/sync/libc_pthread_mutex_default_deadlock.rs
+++ b/tests/fail/sync/libc_pthread_mutex_default_deadlock.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     unsafe {
         let mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
diff --git a/tests/fail/sync/libc_pthread_mutex_destroy_locked.rs b/tests/fail/sync/libc_pthread_mutex_destroy_locked.rs
index fc69ace369..0f74446fa2 100644
--- a/tests/fail/sync/libc_pthread_mutex_destroy_locked.rs
+++ b/tests/fail/sync/libc_pthread_mutex_destroy_locked.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     unsafe {
         let mut mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
diff --git a/tests/fail/sync/libc_pthread_mutex_double_destroy.rs b/tests/fail/sync/libc_pthread_mutex_double_destroy.rs
index 9b539afc19..89022f3b56 100644
--- a/tests/fail/sync/libc_pthread_mutex_double_destroy.rs
+++ b/tests/fail/sync/libc_pthread_mutex_double_destroy.rs
@@ -2,7 +2,6 @@
 #![feature(rustc_private)]
 
 /// Test that destroying a pthread_mutex twice fails, even without a check for number validity
-extern crate libc;
 
 fn main() {
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_mutex_normal_deadlock.rs b/tests/fail/sync/libc_pthread_mutex_normal_deadlock.rs
index 944e86e106..ab6d9c7739 100644
--- a/tests/fail/sync/libc_pthread_mutex_normal_deadlock.rs
+++ b/tests/fail/sync/libc_pthread_mutex_normal_deadlock.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     unsafe {
         let mut mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
diff --git a/tests/fail/sync/libc_pthread_mutex_normal_unlock_unlocked.rs b/tests/fail/sync/libc_pthread_mutex_normal_unlock_unlocked.rs
index c2bdce82b6..f259a4dee7 100644
--- a/tests/fail/sync/libc_pthread_mutex_normal_unlock_unlocked.rs
+++ b/tests/fail/sync/libc_pthread_mutex_normal_unlock_unlocked.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     unsafe {
         let mut mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
diff --git a/tests/fail/sync/libc_pthread_mutex_wrong_owner.rs b/tests/fail/sync/libc_pthread_mutex_wrong_owner.rs
index eea4db7115..b8e57f8f74 100644
--- a/tests/fail/sync/libc_pthread_mutex_wrong_owner.rs
+++ b/tests/fail/sync/libc_pthread_mutex_wrong_owner.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::cell::UnsafeCell;
 use std::sync::Arc;
 use std::thread;
diff --git a/tests/fail/sync/libc_pthread_mutexattr_double_destroy.rs b/tests/fail/sync/libc_pthread_mutexattr_double_destroy.rs
index 620dbb94a7..ac6292570e 100644
--- a/tests/fail/sync/libc_pthread_mutexattr_double_destroy.rs
+++ b/tests/fail/sync/libc_pthread_mutexattr_double_destroy.rs
@@ -2,7 +2,6 @@
 #![feature(rustc_private)]
 
 /// Test that destroying a pthread_mutexattr twice fails, even without a check for number validity
-extern crate libc;
 
 fn main() {
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_rwlock_destroy_read_locked.rs b/tests/fail/sync/libc_pthread_rwlock_destroy_read_locked.rs
index 67b77ff286..ae7c1bbde7 100644
--- a/tests/fail/sync/libc_pthread_rwlock_destroy_read_locked.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_destroy_read_locked.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_rwlock_destroy_write_locked.rs b/tests/fail/sync/libc_pthread_rwlock_destroy_write_locked.rs
index 5bc5fe3c6b..9642595ca4 100644
--- a/tests/fail/sync/libc_pthread_rwlock_destroy_write_locked.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_destroy_write_locked.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_rwlock_double_destroy.rs b/tests/fail/sync/libc_pthread_rwlock_double_destroy.rs
index 7e756c5bb8..81b1661ce8 100644
--- a/tests/fail/sync/libc_pthread_rwlock_double_destroy.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_double_destroy.rs
@@ -2,7 +2,6 @@
 #![feature(rustc_private)]
 
 /// Test that destroying a pthread_rwlock twice fails, even without a check for number validity
-extern crate libc;
 
 fn main() {
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.rs b/tests/fail/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.rs
index 76fceb315f..158dd8c1cd 100644
--- a/tests/fail/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_rwlock_read_wrong_owner.rs b/tests/fail/sync/libc_pthread_rwlock_read_wrong_owner.rs
index e971fd8c30..23dda68c6a 100644
--- a/tests/fail/sync/libc_pthread_rwlock_read_wrong_owner.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_read_wrong_owner.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::cell::UnsafeCell;
 use std::sync::Arc;
 use std::thread;
diff --git a/tests/fail/sync/libc_pthread_rwlock_unlock_unlocked.rs b/tests/fail/sync/libc_pthread_rwlock_unlock_unlocked.rs
index 29cfd36caf..fdcf8e41d3 100644
--- a/tests/fail/sync/libc_pthread_rwlock_unlock_unlocked.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_unlock_unlocked.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_rwlock_write_read_deadlock.rs b/tests/fail/sync/libc_pthread_rwlock_write_read_deadlock.rs
index e9c5c17f3e..adbb95fc28 100644
--- a/tests/fail/sync/libc_pthread_rwlock_write_read_deadlock.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_write_read_deadlock.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::cell::UnsafeCell;
 use std::sync::Arc;
 use std::thread;
diff --git a/tests/fail/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.rs b/tests/fail/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.rs
index 5ed25344e7..a7d16caa7a 100644
--- a/tests/fail/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_rwlock_write_write_deadlock.rs b/tests/fail/sync/libc_pthread_rwlock_write_write_deadlock.rs
index 3d15370e83..070373255d 100644
--- a/tests/fail/sync/libc_pthread_rwlock_write_write_deadlock.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_write_write_deadlock.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::cell::UnsafeCell;
 use std::sync::Arc;
 use std::thread;
diff --git a/tests/fail/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.rs b/tests/fail/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.rs
index 14361bee54..867c6272c4 100644
--- a/tests/fail/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
     unsafe {
diff --git a/tests/fail/sync/libc_pthread_rwlock_write_wrong_owner.rs b/tests/fail/sync/libc_pthread_rwlock_write_wrong_owner.rs
index 668ccb3eca..cff2a7a2e9 100644
--- a/tests/fail/sync/libc_pthread_rwlock_write_wrong_owner.rs
+++ b/tests/fail/sync/libc_pthread_rwlock_write_wrong_owner.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::cell::UnsafeCell;
 use std::sync::Arc;
 use std::thread;
diff --git a/tests/fail/tokio_mvp.rs b/tests/fail/tokio_mvp.rs
new file mode 100644
index 0000000000..7cb42c09a9
--- /dev/null
+++ b/tests/fail/tokio_mvp.rs
@@ -0,0 +1,7 @@
+//@compile-flags: -Zmiri-disable-isolation
+//@error-pattern: can't call foreign function: epoll_create1
+//@normalize-stderr-test: "   = note: inside .*\n" -> ""
+//@only-target-linux: the errors differ too much between platforms
+
+#[tokio::main]
+async fn main() {}
diff --git a/tests/fail/tokio_mvp.stderr b/tests/fail/tokio_mvp.stderr
new file mode 100644
index 0000000000..cff948f364
--- /dev/null
+++ b/tests/fail/tokio_mvp.stderr
@@ -0,0 +1,19 @@
+error: unsupported operation: can't call foreign function: epoll_create1
+  --> CARGO_REGISTRY/epoll.rs:LL:CC
+   |
+LL |         syscall!(epoll_create1(flag)).map(|ep| Selector {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't call foreign function: epoll_create1
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: backtrace:
+note: inside `main` at $DIR/tokio_mvp.rs:LL:CC
+  --> $DIR/tokio_mvp.rs:LL:CC
+   |
+LL | #[tokio::main]
+   | ^^^^^^^^^^^^^^
+   = note: this error originates in the macro `syscall` which comes from the expansion of the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/tests/fail/unsupported_signal.rs b/tests/fail/unsupported_signal.rs
index e9bd340fca..20ebcc9bc4 100644
--- a/tests/fail/unsupported_signal.rs
+++ b/tests/fail/unsupported_signal.rs
@@ -3,8 +3,6 @@
 //@ignore-target-windows: No libc on Windows
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     unsafe {
         libc::signal(libc::SIGPIPE, libc::SIG_IGN);
diff --git a/tests/panic/panic/unsupported_syscall.rs b/tests/panic/panic/unsupported_syscall.rs
index a689172814..27595bf107 100644
--- a/tests/panic/panic/unsupported_syscall.rs
+++ b/tests/panic/panic/unsupported_syscall.rs
@@ -3,8 +3,6 @@
 //@compile-flags: -Zmiri-panic-on-unsupported
 #![feature(rustc_private)]
 
-extern crate libc;
-
 fn main() {
     unsafe {
         libc::syscall(0);
diff --git a/tests/pass/calloc.rs b/tests/pass/calloc.rs
index a9efb776b6..e155d53ce8 100644
--- a/tests/pass/calloc.rs
+++ b/tests/pass/calloc.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use core::slice;
 
 fn main() {
diff --git a/tests/pass/concurrency/libc_pthread_cond.rs b/tests/pass/concurrency/libc_pthread_cond.rs
index eb491486be..c5b0e86666 100644
--- a/tests/pass/concurrency/libc_pthread_cond.rs
+++ b/tests/pass/concurrency/libc_pthread_cond.rs
@@ -6,8 +6,6 @@
 
 /// Test that conditional variable timeouts are working properly with both
 /// monotonic and system clocks.
-extern crate libc;
-
 use std::mem::MaybeUninit;
 use std::time::Instant;
 
diff --git a/tests/pass/concurrency/linux-futex.rs b/tests/pass/concurrency/linux-futex.rs
index f9c87e0723..43216481e7 100644
--- a/tests/pass/concurrency/linux-futex.rs
+++ b/tests/pass/concurrency/linux-futex.rs
@@ -2,7 +2,6 @@
 //@compile-flags: -Zmiri-disable-isolation
 
 #![feature(rustc_private)]
-extern crate libc;
 
 use std::mem::MaybeUninit;
 use std::ptr;
diff --git a/tests/pass/concurrency/tls_pthread_drop_order.rs b/tests/pass/concurrency/tls_pthread_drop_order.rs
index c9e8b9271c..1ccc57da25 100644
--- a/tests/pass/concurrency/tls_pthread_drop_order.rs
+++ b/tests/pass/concurrency/tls_pthread_drop_order.rs
@@ -1,7 +1,6 @@
 //@ignore-target-windows: No libc on Windows
 
 #![feature(rustc_private)]
-extern crate libc;
 
 use std::mem;
 use std::ptr;
diff --git a/tests/pass/foreign-fn-linkname.rs b/tests/pass/foreign-fn-linkname.rs
index 391b182fda..40aeb2ef63 100644
--- a/tests/pass/foreign-fn-linkname.rs
+++ b/tests/pass/foreign-fn-linkname.rs
@@ -1,8 +1,6 @@
 //ignore-windows: Uses POSIX APIs
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::ffi::CString;
 
 mod mlibc {
diff --git a/tests/pass/fs.rs b/tests/pass/fs.rs
index aa5cd83c69..9d59fedb20 100644
--- a/tests/pass/fs.rs
+++ b/tests/pass/fs.rs
@@ -4,8 +4,6 @@
 #![feature(rustc_private)]
 #![feature(io_error_more)]
 
-extern crate libc;
-
 use std::ffi::CString;
 use std::fs::{
     create_dir, read_dir, read_link, remove_dir, remove_dir_all, remove_file, rename, File,
diff --git a/tests/pass/fs_with_isolation.rs b/tests/pass/fs_with_isolation.rs
index 41ada94e27..f73e64ad17 100644
--- a/tests/pass/fs_with_isolation.rs
+++ b/tests/pass/fs_with_isolation.rs
@@ -4,8 +4,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::ffi::CString;
 use std::fs::{self, File};
 use std::io::{Error, ErrorKind};
diff --git a/tests/pass/libc.rs b/tests/pass/libc.rs
index 99b7c3f249..9b83ab45b0 100644
--- a/tests/pass/libc.rs
+++ b/tests/pass/libc.rs
@@ -5,8 +5,6 @@
 use std::fs::{remove_file, File};
 use std::os::unix::io::AsRawFd;
 
-extern crate libc;
-
 fn tmp() -> std::path::PathBuf {
     std::env::var("MIRI_TEMP")
         .map(std::path::PathBuf::from)
diff --git a/tests/pass/linux-getrandom-without-isolation.rs b/tests/pass/linux-getrandom-without-isolation.rs
index fea3bb3fdc..12b42552bd 100644
--- a/tests/pass/linux-getrandom-without-isolation.rs
+++ b/tests/pass/linux-getrandom-without-isolation.rs
@@ -1,7 +1,6 @@
 //@only-target-linux
 //@compile-flags: -Zmiri-disable-isolation
 #![feature(rustc_private)]
-extern crate libc;
 
 use std::ptr;
 
diff --git a/tests/pass/linux-getrandom.rs b/tests/pass/linux-getrandom.rs
index 1d0ab6ed74..e3309f480d 100644
--- a/tests/pass/linux-getrandom.rs
+++ b/tests/pass/linux-getrandom.rs
@@ -1,6 +1,5 @@
 //@only-target-linux
 #![feature(rustc_private)]
-extern crate libc;
 
 use std::ptr;
 
diff --git a/tests/pass/malloc.rs b/tests/pass/malloc.rs
index d20ceddbb8..9066e2af25 100644
--- a/tests/pass/malloc.rs
+++ b/tests/pass/malloc.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use core::{ptr, slice};
 
 fn main() {
diff --git a/tests/pass/random.rs b/tests/pass/random.rs
new file mode 100644
index 0000000000..808d1006d4
--- /dev/null
+++ b/tests/pass/random.rs
@@ -0,0 +1,22 @@
+use rand::{rngs::SmallRng, Rng, SeedableRng};
+// mac-os `getrandom_1` does some pointer shenanigans
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    // Test `getrandom` directly (in multiple different versions).
+    let mut data = vec![0; 16];
+    getrandom_1::getrandom(&mut data).unwrap();
+    getrandom_2::getrandom(&mut data).unwrap();
+
+    // Try seeding with "real" entropy.
+    let mut rng = SmallRng::from_entropy();
+    let _val = rng.gen::<i32>();
+    let _val = rng.gen::<isize>();
+    let _val = rng.gen::<i128>();
+
+    // Also try per-thread RNG.
+    let mut rng = rand::thread_rng();
+    let _val = rng.gen::<i32>();
+    let _val = rng.gen::<isize>();
+    let _val = rng.gen::<i128>();
+}
diff --git a/tests/pass/regions-mock-trans.rs b/tests/pass/regions-mock-trans.rs
index 5dafc88756..7432ea9582 100644
--- a/tests/pass/regions-mock-trans.rs
+++ b/tests/pass/regions-mock-trans.rs
@@ -2,8 +2,6 @@
 
 #![feature(rustc_private)]
 
-extern crate libc;
-
 use std::mem;
 
 struct Arena(());
diff --git a/ui_test/Cargo.lock b/ui_test/Cargo.lock
index 2065cc34be..9addea9b19 100644
--- a/ui_test/Cargo.lock
+++ b/ui_test/Cargo.lock
@@ -67,6 +67,37 @@ dependencies = [
  "rustc-demangle",
 ]
 
+[[package]]
+name = "camino"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "869119e97797867fd90f5e22af7d0bd274bd4635ebb9eb68c04f3f513ae6c412"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "cargo-platform"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cbdb825da8a5df079a43676dbe042702f1707b1109f713a01420fbb4cc71fa27"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "cargo_metadata"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3abb7553d5b9b8421c6de7cb02606ff15e0c6eea7d8eadd75ef013fd636bec36"
+dependencies = [
+ "camino",
+ "cargo-platform",
+ "semver",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "cc"
 version = "1.0.73"
@@ -390,6 +421,9 @@ name = "semver"
 version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8cb243bdfdb5936c8dc3c45762a19d12ab4550cdc753bc247637d4ec35a040fd"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "serde"
@@ -497,6 +531,7 @@ dependencies = [
 name = "ui_test"
 version = "0.1.0"
 dependencies = [
+ "cargo_metadata",
  "color-eyre",
  "colored",
  "crossbeam",
diff --git a/ui_test/Cargo.toml b/ui_test/Cargo.toml
index cdc5e5db47..bb14eb7ecf 100644
--- a/ui_test/Cargo.toml
+++ b/ui_test/Cargo.toml
@@ -18,4 +18,4 @@ lazy_static = "1.4.0"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 color-eyre = { version = "0.6.1", default-features = false, features = ["capture-spantrace"] }
-
+cargo_metadata = "0.15"
diff --git a/ui_test/README.md b/ui_test/README.md
index f1b1a5d67e..3db3361faa 100644
--- a/ui_test/README.md
+++ b/ui_test/README.md
@@ -47,3 +47,5 @@ their command specifies, or the test will fail without even being run.
 
 * `ignore-target-*` and `only-target-*` opereate solely on the triple, instead of supporting things like `macos`
 * only `//~` comments can be individualized per revision
+* only supports `ui` tests
+* tests are run in named order, so you can prefix slow tests with `0` in order to make them get run first
diff --git a/ui_test/src/dependencies.rs b/ui_test/src/dependencies.rs
new file mode 100644
index 0000000000..ab3a015659
--- /dev/null
+++ b/ui_test/src/dependencies.rs
@@ -0,0 +1,137 @@
+use color_eyre::eyre::{bail, Result};
+use std::{
+    collections::{HashMap, HashSet},
+    path::{Path, PathBuf},
+    process::Command,
+};
+
+use crate::Config;
+
+#[derive(Default, Debug)]
+pub struct Dependencies {
+    /// All paths that must be imported with `-L dependency=`. This is for
+    /// finding proc macros run on the host and dependencies for the target.
+    pub import_paths: Vec<PathBuf>,
+    /// The name as chosen in the `Cargo.toml` and its corresponding rmeta file.
+    pub dependencies: Vec<(String, PathBuf)>,
+}
+
+/// Compiles dependencies and returns the crate names and corresponding rmeta files.
+pub fn build_dependencies(config: &Config) -> Result<Dependencies> {
+    let manifest_path = match &config.dependencies_crate_manifest_path {
+        Some(path) => path,
+        None => return Ok(Default::default()),
+    };
+    let (program, args, envs): (&Path, &[_], &[_]) = match &config.dependency_builder {
+        Some(db) => (&db.program, &db.args, &db.envs),
+        None => (Path::new("cargo"), &[], &[]),
+    };
+    let mut build = Command::new(program);
+    build.args(args);
+    // HACK: we're using `cargo run` (or `cargo miri run`), because the latter does not
+    // support `cargo miri build` yet.
+    build.arg("run");
+
+    if let Some(target) = &config.target {
+        build.arg(format!("--target={target}"));
+    }
+
+    // Reusable closure for setting up the environment both for artifact generation and `cargo_metadata`
+    let setup_command = |cmd: &mut Command| {
+        cmd.envs(envs.iter().map(|(k, v)| (k, v)));
+        cmd.arg("--manifest-path").arg(manifest_path);
+    };
+
+    setup_command(&mut build);
+    build
+        .arg("--target-dir=target/test_dependencies")
+        .arg("--message-format=json")
+        .arg("-Zunstable-options");
+
+    let output = build.output()?;
+
+    if !output.status.success() {
+        let stdout = String::from_utf8(output.stdout)?;
+        let stderr = String::from_utf8(output.stderr)?;
+        bail!("failed to compile dependencies:\nstderr:\n{stderr}\n\nstdout:{stdout}");
+    }
+
+    // Collect all artifacts generated
+    let output = output.stdout;
+    let output = String::from_utf8(output)?;
+    let mut import_paths: HashSet<PathBuf> = HashSet::new();
+    let mut artifacts: HashMap<_, _> = output
+        .lines()
+        .filter_map(|line| {
+            let message = serde_json::from_str::<cargo_metadata::Message>(line).ok()?;
+            if let cargo_metadata::Message::CompilerArtifact(artifact) = message {
+                for filename in &artifact.filenames {
+                    import_paths.insert(filename.parent().unwrap().into());
+                }
+                let filename = artifact
+                    .filenames
+                    .into_iter()
+                    .find(|filename| filename.extension() == Some("rmeta"))?;
+                Some((artifact.package_id, filename.into_std_path_buf()))
+            } else {
+                None
+            }
+        })
+        .collect();
+
+    // Check which crates are mentioned in the crate itself
+    let mut metadata = cargo_metadata::MetadataCommand::new().cargo_command();
+    setup_command(&mut metadata);
+    let output = metadata.output()?;
+
+    if !output.status.success() {
+        let stdout = String::from_utf8(output.stdout)?;
+        let stderr = String::from_utf8(output.stderr)?;
+        bail!("failed to run cargo-metadata:\nstderr:\n{stderr}\n\nstdout:{stdout}");
+    }
+
+    let output = output.stdout;
+    let output = String::from_utf8(output)?;
+
+    for line in output.lines() {
+        if !line.starts_with('{') {
+            continue;
+        }
+        let metadata: cargo_metadata::Metadata = serde_json::from_str(line)?;
+        // Only take artifacts that are defined in the Cargo.toml
+
+        // First, find the root artifact
+        let root = metadata
+            .packages
+            .iter()
+            .find(|package| {
+                package.manifest_path.as_std_path().canonicalize().unwrap()
+                    == manifest_path.canonicalize().unwrap()
+            })
+            .unwrap();
+
+        // Then go over all of its dependencies
+        let dependencies = root
+            .dependencies
+            .iter()
+            .map(|package| {
+                // Get the id for the package matching the version requirement of the dep
+                let id = &metadata
+                    .packages
+                    .iter()
+                    .find(|&dep| dep.name == package.name && package.req.matches(&dep.version))
+                    .expect("dependency does not exist")
+                    .id;
+                // Return the name chosen in `Cargo.toml` and the path to the corresponding artifact
+                (
+                    package.rename.clone().unwrap_or_else(|| package.name.clone()),
+                    artifacts.remove(id).expect("package without artifact"),
+                )
+            })
+            .collect();
+        let import_paths = import_paths.into_iter().collect();
+        return Ok(Dependencies { dependencies, import_paths });
+    }
+
+    bail!("no json found in cargo-metadata output")
+}
diff --git a/ui_test/src/lib.rs b/ui_test/src/lib.rs
index 917e382379..4318e8a8e0 100644
--- a/ui_test/src/lib.rs
+++ b/ui_test/src/lib.rs
@@ -1,6 +1,7 @@
 #![allow(clippy::enum_variant_names, clippy::useless_format, clippy::too_many_arguments)]
 
 use std::collections::VecDeque;
+use std::ffi::OsString;
 use std::fmt::Write;
 use std::path::{Path, PathBuf};
 use std::process::{Command, ExitStatus};
@@ -14,8 +15,10 @@ use parser::{ErrorMatch, Pattern};
 use regex::Regex;
 use rustc_stderr::{Level, Message};
 
+use crate::dependencies::build_dependencies;
 use crate::parser::{Comments, Condition};
 
+mod dependencies;
 mod parser;
 mod rustc_stderr;
 #[cfg(test)]
@@ -24,7 +27,7 @@ mod tests;
 #[derive(Debug)]
 pub struct Config {
     /// Arguments passed to the binary that is executed.
-    pub args: Vec<String>,
+    pub args: Vec<OsString>,
     /// `None` to run on the host, otherwise a target triple
     pub target: Option<String>,
     /// Filters applied to stderr output before processing it
@@ -38,6 +41,18 @@ pub struct Config {
     pub output_conflict_handling: OutputConflictHandling,
     /// Only run tests with one of these strings in their path/name
     pub path_filter: Vec<String>,
+    /// Path to a `Cargo.toml` that describes which dependencies the tests can access.
+    pub dependencies_crate_manifest_path: Option<PathBuf>,
+    /// Can be used to override what command to run instead of `cargo` to build the
+    /// dependencies in `manifest_path`
+    pub dependency_builder: Option<DependencyBuilder>,
+}
+
+#[derive(Debug)]
+pub struct DependencyBuilder {
+    pub program: PathBuf,
+    pub args: Vec<String>,
+    pub envs: Vec<(String, String)>,
 }
 
 #[derive(Debug)]
@@ -53,12 +68,26 @@ pub enum OutputConflictHandling {
 
 pub type Filter = Vec<(Regex, &'static str)>;
 
-pub fn run_tests(config: Config) -> Result<()> {
+pub fn run_tests(mut config: Config) -> Result<()> {
     eprintln!("   Compiler flags: {:?}", config.args);
 
     // Get the triple with which to run the tests
     let target = config.target.clone().unwrap_or_else(|| config.get_host());
 
+    let dependencies = build_dependencies(&config)?;
+    for (name, dependency) in dependencies.dependencies {
+        config.args.push("--extern".into());
+        let mut dep = OsString::from(name);
+        dep.push("=");
+        dep.push(dependency);
+        config.args.push(dep);
+    }
+    for import_path in dependencies.import_paths {
+        config.args.push("-L".into());
+        config.args.push(import_path.into());
+    }
+    let config = config;
+
     // A channel for files to process
     let (submit, receive) = crossbeam::channel::unbounded();
 
@@ -294,9 +323,7 @@ fn run_test(
     for arg in &comments.compile_flags {
         miri.arg(arg);
     }
-    for (k, v) in &comments.env_vars {
-        miri.env(k, v);
-    }
+    miri.envs(comments.env_vars.iter().map(|(k, v)| (k, v)));
     let output = miri.output().expect("could not execute miri");
     let mut errors = config.mode.ok(output.status);
     let stderr = check_test_result(
diff --git a/ui_test/src/tests.rs b/ui_test/src/tests.rs
index 96c0f362b6..8b0bd517a1 100644
--- a/ui_test/src/tests.rs
+++ b/ui_test/src/tests.rs
@@ -16,6 +16,8 @@ fn config() -> Config {
         path_filter: vec![],
         program: PathBuf::from("cake"),
         output_conflict_handling: OutputConflictHandling::Error,
+        dependencies_crate_manifest_path: None,
+        dependency_builder: None,
     }
 }