During the sanity check, we keep track of the path we are below in a `Vec`. We
avoid cloning that `Vec` unless we hit a pointer indirection. The `String`
representation is only computed when validation actually fails.
This is still roughly 45ns slower than the old state, because it now works with
an MPlaceTy and uses the appropriate abstractions, instead of working with a
ptr-align pair directly.
* Value gets renamed to Operand, so that now interpret::{Place, Operand} are the
"dynamic" versions of mir::{Place, Operand}.
* Operand and Place share the data for their "stuff is in memory"-base in a new
type, MemPlace. This also makes it possible to give some more precise types
in other areas. Both Operand and MemPlace have methods available to project
into fields (and other kinds of projections) without causing further
allocations.
* The type for "a Scalar or a ScalarPair" is called Value, and again used to
give some more precise types.
* All of these have versions with an attached layout, so that we can more often
drag the layout along instead of recomputing it. This lets us get rid of
`PlaceExtra::Downcast`. MPlaceTy and PlaceTy can only be constructed
in place.rs, making sure the layout is handled properly.
(The same should eventually be done for ValTy and OpTy.)
* All the high-level functions to write typed memory take a Place, and live in
place.rs. All the high-level typed functions to read typed memory take an
Operand, and live in operands.rs.
Exec gdb/lldb in rust-{gdb/lldb} wrapper scripts
This way, the process we get by executing `rust-gdb` or `rust-lldb` (eventually) is an actual `gdb` or `lldb` process and behaves accordingly. Previously (and at least to me unexpectedly) it was just a script waiting for the debugger to exit. Sending a signal (e.g. SIGINT) to the spawned process did therefore not affect the debugger process (which was just a child of the wrapper script).
In order to work around that we `exec` (according to [this](http://pubs.opengroup.org/onlinepubs/009695399/utilities/exec.html) part of the posix shell) and replace the script process with the debugger in the last line of the script. The lldb script had to be modified to not pass the configuration commands via a script file (which in my opinion is cleaner anyway).
This comment was added more than 5 years ago in ab03c1e422. As far as
anyone reading this comment today needs to know, the function has never
parsed items from inside an extern crate.
Exhaustive integer matching
This adds a new feature flag `exhaustive_integer_patterns` that enables exhaustive matching of integer types by their values. For example, the following is now accepted:
```rust
#![feature(exhaustive_integer_patterns)]
#![feature(exclusive_range_pattern)]
fn matcher(x: u8) {
match x { // ok
0 .. 32 => { /* foo */ }
32 => { /* bar */ }
33 ..= 255 => { /* baz */ }
}
}
```
This matching is permitted on all integer (signed/unsigned and char) types. Sensible error messages are also provided. For example:
```rust
fn matcher(x: u8) {
match x { //~ ERROR
0 .. 32 => { /* foo */ }
}
}
```
results in:
```
error[E0004]: non-exhaustive patterns: `32u8...255u8` not covered
--> matches.rs:3:9
|
6 | match x {
| ^ pattern `32u8...255u8` not covered
```
This implements https://github.com/rust-lang/rfcs/issues/1550 for https://github.com/rust-lang/rust/issues/50907. While there hasn't been a full RFC for this feature, it was suggested that this might be a feature that obviously complements the existing exhaustiveness checks (e.g. for `bool`) and so a feature gate would be sufficient for now.
People often come looking for some kind of `as_ref_unchecked` method on
raw pointers that would give them `&T` and not `Option<&T>` when they
are sure the pointer is not NULL.
There's no such method, but taking a reference of the dereferenced
pointer accomplishes the same thing. Therefore, suggest using that, at
the `as_ref` site ‒ it's a place people are likely going to look into.
Rollup of 17 pull requests
Successful merges:
- #53030 (Updated RELEASES.md for 1.29.0)
- #53104 (expand the documentation on the `Unpin` trait)
- #53213 (Stabilize IP associated constants)
- #53296 (When closure with no arguments was expected, suggest wrapping)
- #53329 (Replace usages of ptr::offset with ptr::{add,sub}.)
- #53363 (add individual docs to `core::num::NonZero*`)
- #53370 (Stabilize macro_vis_matcher)
- #53393 (Mark libserialize functions as inline)
- #53405 (restore the page title after escaping out of a search)
- #53452 (Change target triple used to check for lldb in build-manifest)
- #53462 (Document Box::into_raw returns non-null ptr)
- #53465 (Remove LinkMeta struct)
- #53492 (update lld submodule to include RISCV patch)
- #53496 (Fix typos found by codespell.)
- #53521 (syntax: Optimize some literal parsing)
- #53540 (Moved issue-53157.rs into src/test/ui/consts/const-eval/)
- #53551 (Avoid some Place clones.)
Failed merges:
r? @ghost
