Add tracing to resolve-related functions
Resolve-related functions are not called often but still make up for ~3% of execution time for non-repetitive programs (as seen in the first table below, obtained from running the rust snippet at the bottom with `n=1`). On the other hand, for repetitive programs they become less relevant (I tested the same snippet but with `n=100` and got ~1.5%), and it appears that only `try_resolve` is called more often (see the last two tables).
The first table was obtained by opening the trace file in https://ui.perfetto.dev and running the following query:
```sql
select "TOTAL PROGRAM DURATION" as name, count(*), max(ts + dur) as "sum(dur)", 100.0 as "%", null as "min(dur)", null as "max(dur)", null as "avg(dur)", null as "stddev(dur)" from slices union select "TOTAL OVER ALL SPANS (excluding events)" as name, count(*), sum(dur), cast(cast(sum(dur) as float) / (select max(ts + dur) from slices) * 1000 as int) / 10.0 as "%", min(dur), max(dur), cast(avg(dur) as int) as "avg(dur)", cast(sqrt(avg(dur*dur)-avg(dur)*avg(dur)) as int) as "stddev(dur)" from slices where parent_id is null and name != "frame" and name != "step" and dur > 0 union select name, count(*), sum(dur), cast(cast(sum(dur) as float) / (select max(ts + dur) from slices) * 1000 as int) / 10.0 as "%", min(dur), max(dur), cast(avg(dur) as int) as "avg(dur)", cast(sqrt(avg(dur*dur)-avg(dur)*avg(dur)) as int) as "stddev(dur)" from slices where parent_id is null and name != "frame" and name != "step" group by name order by sum(dur) desc, count(*) desc
```
<img width="1687" height="242" alt="image" src="https://github.com/user-attachments/assets/4d4bd890-869b-40f3-a473-8e4c42b02da4" />
The following two tables show how many `resolve` spans there per subname/subcategory, and how much time is spent in each. The first is for `n=1` and the second for `n=100`. The query that was used is:
```sql
select args.string_value as name, count(*), max(dur), avg(dur), sum(dur) from slices inner join args USING (arg_set_id) where args.key = "args." || slices.name and name = "resolve" group by args.string_value
```
<img width="1688" height="159" alt="image" src="https://github.com/user-attachments/assets/a8749856-c099-492e-a86e-6d67b146af9c" />
<img width="1688" height="159" alt="image" src="https://github.com/user-attachments/assets/ce3ac1b5-5c06-47d9-85a6-9b921aea348e" />
The snippet I tested with Miri to obtain the above traces is:
```rust
fn main() {
let n: usize = std::env::args().nth(1).unwrap().parse().unwrap();
let mut v = (0..n).into_iter().collect::<Vec<_>>();
for i in &mut v {
*i += 1;
}
}
```
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````
