tell people how to set miri flags

cargo-miri/src/phases.rs

@@ -23,6 +23,12 @@ Subcommands:
  clean Clean the Miri cache & target directory
 
 The cargo options are exactly the same as for `cargo run` and `cargo test`, respectively.
+Furthermore, the following extra flags and environment variables are recognized for `run` and `test`:
+
+ --many-seeds[=from..to] Run the program/tests many times with different seeds in the given range.
+ The range defaults to `0..64`.
+
+ MIRIFLAGS Extra flags to pass to the Miri driver. Use this to pass `-Zmiri-...` flags.
 
 Examples:
  cargo miri run

src/diagnostics.rs

@@ -227,8 +227,8 @@ pub fn report_error<'tcx>(
  let helps = match info {
  UnsupportedInIsolation(_) =>
  vec![
- (None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
- (None, format!("or pass `-Zmiri-isolation-error=warn` to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning")),
+ (None, format!("set `MIRIFLAGS=-Zmiri-disable-isolation` to disable isolation;")),
+ (None, format!("or set `MIRIFLAGS=-Zmiri-isolation-error=warn` to make Miri return an error code from isolated operations (if supported for that operation) and continue with a warning")),
  ],
  UnsupportedForeignItem(_) => {
  vec![
@@ -463,19 +463,22 @@ pub fn report_leaks<'tcx>(
 ) {
  let mut any_pruned = false;
  for (id, kind, mut alloc) in leaks {
+ let mut title = format!(
+ "memory leaked: {id:?} ({}, size: {:?}, align: {:?})",
+ kind,
+ alloc.size().bytes(),
+ alloc.align.bytes()
+ );
  let Some(backtrace) = alloc.extra.backtrace.take() else {
+ ecx.tcx.dcx().err(title);
  continue;
  };
+ title.push_str(", allocated here:");
  let (backtrace, pruned) = prune_stacktrace(backtrace, &ecx.machine);
  any_pruned |= pruned;
  report_msg(
  DiagLevel::Error,
- format!(
- "memory leaked: {id:?} ({}, size: {:?}, align: {:?}), allocated here:",
- kind,
- alloc.size().bytes(),
- alloc.align.bytes()
- ),
+ title,
  vec![],
  vec![],
  vec![],
@@ -642,13 +645,9 @@ impl<'tcx> MiriMachine<'tcx> {
  (
  None,
  format!(
- "This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`,"
+ "This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program."
  ),
  ),
- (
- None,
- format!("which means that Miri might miss pointer bugs in this program."),
- ),
  (
  None,
  format!(
@@ -664,13 +663,13 @@ impl<'tcx> MiriMachine<'tcx> {
  (
  None,
  format!(
- "You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `with_exposed_provenance` semantics."
+ "You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics."
  ),
  ),
  (
  None,
  format!(
- "Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning."
+ "Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning."
  ),
  ),
  ],

src/eval.rs

@@ -468,22 +468,15 @@ pub fn eval_entry<'tcx>(
  // Check for thread leaks.
  if !ecx.have_all_terminated() {
  tcx.dcx().err("the main thread terminated without waiting for all remaining threads");
- tcx.dcx().note("pass `-Zmiri-ignore-leaks` to disable this check");
+ tcx.dcx().note("set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check");
  return None;
  }
  // Check for memory leaks.
  info!("Additional static roots: {:?}", ecx.machine.static_roots);
  let leaks = ecx.find_leaked_allocations(&ecx.machine.static_roots);
  if !leaks.is_empty() {
  report_leaks(&ecx, leaks);
- let leak_message = "the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check";
- if ecx.machine.collect_leak_backtraces {
- // If we are collecting leak backtraces, each leak is a distinct error diagnostic.
- tcx.dcx().note(leak_message);
- } else {
- // If we do not have backtraces, we just report an error without any span.
- tcx.dcx().err(leak_message);
- };
+ tcx.dcx().note("set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check");
  // Ignore the provided return code - let the reported error
  // determine the return code.
  return None;

tests/fail-dep/concurrency/libc_pthread_create_main_terminate.stderr

@@ -1,6 +1,6 @@
 error: the main thread terminated without waiting for all remaining threads
 
-note: pass `-Zmiri-ignore-leaks` to disable this check
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/fail-dep/libc/aligned_alloc_size_zero_leak.stderr

@@ -9,7 +9,7 @@ LL | aligned_alloc(2, 0);
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-note: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/fail-dep/libc/fs/isolated_stdin.stderr

@@ -4,8 +4,8 @@ error: unsupported operation: `read` from stdin not available when isolation is
 LL | libc::read(0, bytes.as_mut_ptr() as *mut libc::c_void, 512);
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `read` from stdin not available when isolation is enabled
  |
- = help: pass the flag `-Zmiri-disable-isolation` to disable isolation;
- = help: or pass `-Zmiri-isolation-error=warn` to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning
+ = help: set `MIRIFLAGS=-Zmiri-disable-isolation` to disable isolation;
+ = help: or set `MIRIFLAGS=-Zmiri-isolation-error=warn` to make Miri return an error code from isolated operations (if supported for that operation) and continue with a warning
  = note: BACKTRACE:
  = note: inside `main` at $DIR/isolated_stdin.rs:LL:CC
 

tests/fail-dep/libc/malloc_zero_memory_leak.stderr

@@ -9,7 +9,7 @@ LL | let _ptr = libc::malloc(0);
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-note: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/fail-dep/libc/posix_memalign_size_zero_leak.stderr

@@ -9,7 +9,7 @@ LL | let _ = unsafe { libc::posix_memalign(&mut ptr, align, size) };
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-note: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr

@@ -4,12 +4,11 @@ warning: integer-to-pointer cast
 LL | (*p.as_mut_ptr().cast::<[*const i32; 2]>())[0] = 4 as *const i32;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast
  |
- = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`,
- = help: which means that Miri might miss pointer bugs in this program.
+ = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program.
  = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation.
  = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead.
- = help: You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `with_exposed_provenance` semantics.
- = help: Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning.
+ = help: You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics.
+ = help: Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning.
  = note: BACKTRACE:
  = note: inside `main` at $DIR/ptr_metadata_uninit_slice_len.rs:LL:CC
 

tests/fail/memleak.stderr

@@ -18,7 +18,7 @@ LL | std::mem::forget(Box::new(42));
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-note: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/fail/memleak_no_backtrace.rs

@@ -1,5 +1,5 @@
 //@compile-flags: -Zmiri-disable-leak-backtraces
-//@error-in-other-file: the evaluated program leaked memory
+//@error-in-other-file: memory leaked
 //@normalize-stderr-test: ".*│.*" -> "$$stripped$$"
 
 fn main() {

tests/fail/memleak_no_backtrace.stderr

@@ -1,4 +1,6 @@
-error: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check
+error: memory leaked: ALLOC (Rust heap, size: 4, align: 4)
+
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/fail/memleak_rc.64bit.stderr

@@ -19,7 +19,7 @@ LL | let x = Dummy(Rc::new(RefCell::new(None)));
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-note: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/fail/shims/fs/isolated_file.stderr

@@ -4,8 +4,8 @@ error: unsupported operation: `open` not available when isolation is enabled
 LL | let fd = cvt_r(|| unsafe { open64(path.as_ptr(), flags, opts.mode as c_int) })?;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `open` not available when isolation is enabled
  |
- = help: pass the flag `-Zmiri-disable-isolation` to disable isolation;
- = help: or pass `-Zmiri-isolation-error=warn` to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning
+ = help: set `MIRIFLAGS=-Zmiri-disable-isolation` to disable isolation;
+ = help: or set `MIRIFLAGS=-Zmiri-isolation-error=warn` to make Miri return an error code from isolated operations (if supported for that operation) and continue with a warning
  = note: BACKTRACE:
  = note: inside closure at RUSTLIB/std/src/sys/pal/PLATFORM/fs.rs:LL:CC
  = note: inside `std::sys::pal::PLATFORM::cvt_r::<i32, {closure@std::sys::pal::PLATFORM::fs::File::open_c::{closure#0}}>` at RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC

tests/fail/tls_macro_leak.stderr

@@ -27,7 +27,7 @@ LL | | });
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-note: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/fail/tls_static_leak.stderr

@@ -18,7 +18,7 @@ LL | TLS.set(Some(Box::leak(Box::new(123))));
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-note: the evaluated program leaked memory, pass `-Zmiri-ignore-leaks` to disable this check
+note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
 error: aborting due to 1 previous error
 

tests/pass/box.stack.stderr

@@ -4,12 +4,11 @@ warning: integer-to-pointer cast
 LL | let r2 = ((r as usize) + 0) as *mut i32;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast
  |
- = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`,
- = help: which means that Miri might miss pointer bugs in this program.
+ = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program.
  = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation.
  = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead.
- = help: You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `with_exposed_provenance` semantics.
- = help: Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning.
+ = help: You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics.
+ = help: Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning.
  = note: BACKTRACE:
  = note: inside `into_raw` at $DIR/box.rs:LL:CC
 note: inside `main`

tests/pass/extern_types.stack.stderr

@@ -4,12 +4,11 @@ warning: integer-to-pointer cast
 LL | let x: &Foo = unsafe { &*(16 as *const Foo) };
  | ^^^^^^^^^^^^^^^^^^ integer-to-pointer cast
  |
- = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`,
- = help: which means that Miri might miss pointer bugs in this program.
+ = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program.
  = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation.
  = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead.
- = help: You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `with_exposed_provenance` semantics.
- = help: Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning.
+ = help: You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics.
+ = help: Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning.
  = note: BACKTRACE:
  = note: inside `main` at $DIR/extern_types.rs:LL:CC
 

tests/pass/stacked-borrows/issue-miri-2389.stderr

@@ -4,12 +4,11 @@ warning: integer-to-pointer cast
 LL | let wildcard = &root0 as *const Cell<i32> as usize as *const Cell<i32>;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast
  |
- = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`,
- = help: which means that Miri might miss pointer bugs in this program.
+ = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program.
  = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation.
  = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead.
- = help: You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `with_exposed_provenance` semantics.
- = help: Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning.
+ = help: You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics.
+ = help: Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning.
  = note: BACKTRACE:
  = note: inside `main` at $DIR/issue-miri-2389.rs:LL:CC