Reimplement `print_region` in `type_name.rs`.
Broken by rust-lang/rust#144776; this is reachable after all.
Fixesrust-lang/rust#144994.
The commit also adds a lot more cases to the `type-name-basic.rs`, because it's currently very anaemic. This includes some cases where region omission does very badly; these are marked with FIXME.
r? `@fmease`
Broken by #144776; this is reachable after all.
Fixes#144994.
The commit also adds a lot more cases to the `type-name-basic.rs`,
because it's currently very anaemic. This includes some cases where
region omission does very badly; these are marked with FIXME.
Three of them are named `AbsolutePathPrinter`, which is confusing, so
give those names that better indicate how they are used. And then there
is `SymbolPrinter` and `SymbolMangler`, which are renamed as
`LegacySymbolMangler` and `V0SymbolMangler`, better indicating their
similarity.
`Printer` cleanups
The trait `Printer` is implemented by six types, and the sub-trait `PrettyPrinter` is implemented by three of those types. The traits and the impls are complex and a bit of a mess. This PR starts to clean them up.
r? ``@davidtwco``
Do not give function allocations alignment in consteval and Miri.
We do not yet have a (clear and T-lang approved) design for how `#[align(N)]` on functions should affect function pointers' addresses on various platforms, so for now do not give function pointers alignment in consteval and Miri.
----
Old summary:
Not a full solution to <https://github.com/rust-lang/rust/issues/144661>, but fixes the immediate issue by making function allocations all have alignment 1 in consteval, ignoring `#[rustc_align(N)]`, so the compiler doesn't know if any offset other than 0 is non-null.
A more "principlied" solution would probably be to make function pointers to `#[instruction_set(arm::t32)]` functions be at offset 1 of an align-`max(2, align attribute)` allocation instead of at offset 0 of their allocation during consteval, and on wasm to either disallow `#[align(N)]` where N > 1, or to pad the function table such that the function pointer of a `#[align(N)]` function is a multiple of `N` at runtime.
Currently they are mostly named `cx`, which is a terrible name for a
type that impls `Printer`/`PrettyPrinter`, and is easy to confuse with
other types like `TyCtxt`. This commit changes them to `p`. A couple of
existing `p` variables had to be renamed to make way.
This helps me understand the structure of the code a lot.
If any of these are actually reachable, we can put the old code back,
add a new test case, and we will have improved our test coverage.
Generalize `unsize` and `unsize_into` destinations
Just something that I noticed during other work. We do this for most such functions, so let's do it here, too.
r? ``@RalfJung``
Show the offset, length and memory of uninit read errors
r? ``@RalfJung``
I want to improve memory dumps in general. Not sure yet how to do so best within rust diagnostics, but in a perfect world I could generate a dummy in-memory file (that contains the rendered memory dump) that we then can then provide regular rustc `Span`s to. So we'd basically report normal diagnostics for them with squiggly lines and everything.
fix `-Zsanitizer=kcfi` on `#[naked]` functions
fixes https://github.com/rust-lang/rust/issues/143266
With `-Zsanitizer=kcfi`, indirect calls happen via generated intermediate shim that forwards the call. The generated shim preserves the attributes of the original, including `#[unsafe(naked)]`. The shim is not a naked function though, and violates its invariants (like having a body that consists of a single `naked_asm!` call).
My fix here is to match on the `InstanceKind`, and only use `codegen_naked_asm` when the instance is not a `ReifyShim`. That does beg the question whether there are other `InstanceKind`s that could come up. As far as I can tell the answer is no: calling via `dyn` seems to work find, and `#[track_caller]` is disallowed in combination with `#[naked]`.
r? codegen
````@rustbot```` label +A-naked
cc ````@maurer```` ````@rcvalle````
type_id_eq: check that the hash fully matches the type
The previous logic wouldn't always detect when the hash mismatches the provenance. Fix that by adding a new helper, `read_type_id`, that reads a single type ID while fully checking it for validity and consistency.
r? ``@oli-obk``
Make frame spans appear on a separate trace line
This PR changes tracing_chrome's `tracing::Layer` so that if a span has the "tracing_separate_line" field as one of the span arguments, that span is put on a separate trace line. See https://github.com/rust-lang/miri/pull/4451 for an earlier attempt and for screenshots explaining better what I mean by "separate trace line".
This PR also makes the "frame" span use this feature (so it appears on a separate trace line, see https://github.com/rust-lang/miri/pull/4451 for motivation), but passes `tracing::field::Empty` as the span parameter value so it is ignored by other tracing layers (e.g. the logger):
```rust
info_span!("frame", tracing_separate_line = Empty, "{}", instance);
```
<details><summary>Also see the following discussion I had with ``@RalfJung</summary>``
> Is there no way to attach metadata we could use instead?
[These](https://docs.rs/tracing-core/0.1.34/src/tracing_core/metadata.rs.html#57) are the **static** metadata items we can control about a span. We can't add more metadata outside of them. The most relevant are:
- `name` (for the frame span it's currently "frame")
- `target` which acts as the category (for the frame span it's currently "rustc_const_eval::interpret::stack" by default)
- `fields` which contains a list of the *names* of each of the arguments passed to the `span!` macro (for the frame span it's currently ["message"], where "message" is the default identifier for data passed in the `format!` syntax)
When the tracing code is called at runtime, the **dynamic** values of the arguments are collected into a [`ValueSet`](https://docs.rs/tracing-core/0.1.34/src/tracing_core/field.rs.html#166). Each argument value stored there corresponds with one of the static names stored in `fields` (see above).
---
We have already determined that filtering out spans by `name` is not a good idea, and I would say the same goes for `target`. Both the `name` and the `target` fields are printed to stderr when `MIRI_LOG=` is enabled, so changing them to contain an identifier (e.g. "frame:tracing_separate_root" instead of "frame" as the name) would uselessly clutter the text logs (unless we add one more filter [there](https://github.com/rust-lang/rust/blob/master/compiler/rustc_log/src/lib.rs#L137), but then it gets even more complicated).
```rust
// examples of how the above (problematic) solutions would look like
info_span!("frame:tracing_separate_root", "{}", instance);
info_span!(target: "tracing_separate_root", "frame", "{}", instance);
```
---
So that leaves us with `fields` and their runtime values. Now, my initial thought (inspired by [this comment](https://github.com/rust-lang/miri/pull/4451#issuecomment-3068072303)) was to use a field with the static name "tracing_separate_root" and with a dynamic boolean value of "true". In `tracing_chrome.rs` we can easily check if this field is true and act accordingly. This would work but then again this field would also be picked up by the logger when `MIRI_LOG=` is enabled, and would uselessly clutter the text logs.
```rust
// example of how the above (problematic) solution would look like
info_span!("frame", tracing_separate_root = true, "{}", instance);
```
---
To avoid cluttering the text logs, we can instead set "tracing_separate_root" to the dynamic value of `tracing::field::Empty`. Citing from [here](https://docs.rs/tracing/0.1.41/tracing/field/struct.Empty.html), "when a field’s value is `Empty`, it will not be recorded". "not being recorded" means that the field and its value won't be printed to stderr text logs, nor will it be printed by any other tracing layers that might be attached in the future. In `tracing_chrome.rs` we would still be able to check if "tracing_separate_root" is in the list of static `fields`, and act accordingly. So I believe this solution would effectively allow us to attach metadata to a span in a way that does not clutter logs and still allows being read in `tracing_chrome.rs`.
If we ever wanted to pass arbitrary metadata (i.e. not just a present/not present flag), it would be possible with a custom `Empty` that also holds data and implement `Value` without doing anything ([like `Empty` does](https://docs.rs/tracing-core/0.1.34/src/tracing_core/field.rs.html#775)).
```rust
// example of how the above solution would look like
info_span!("frame", tracing_separate_root = tracing::field::Empty, "{}", instance);
```
</details>
