incr.comp.: Implement compiler diagnostic persistence.
This PR implements storing and loading diagnostics that the compiler generates and thus allows for emitting warnings during incremental compilation without actually re-evaluating the thing the warning originally came from. It also lays some groundwork for storing and loading type information and MIR in the incr. comp. cache.
~~It is still work in progress:~~
- ~~There's still some documentation to be added.~~
- ~~The way anonymous queries are handled might lead to duplicated emissions of warnings. Not sure if there is a better way or how frequent such duplication would be in practice.~~
Diagnostic message duplication is addressed separately in #45519.
r? @nikomatsakis
Optimize some span operations
Do not decode span data twice/thrice/etc unnecessarily.
Applied to stable hashing and all methods in `impl Span`.
Follow up to https://github.com/rust-lang/rust/pull/44646
r? @michaelwoerister
incr.comp.: Fix two problems with HIR hashing.
Fixes https://github.com/rust-lang/rust/issues/45469.
This PR fixes two small problems:
* Overflow checks are always enabled in a constant context, so we need to hash spans of potentially overflowing operations. (Eventually I'd like to handle spans differently so we don't have to make HIR hashing know so much about things like this.)
* The HIR map collector had a bug where it would assign the `DepNode::Hir` instead of the corresponding `DepNode::HirBody` in some nested contexts.
r? @nikomatsakis
Avoid repetition on “use of unstable library feature 'rustc_private'”
This PR fixes the error by only emitting it when the span contains a real file (is not inside a macro) - and making sure it's emitted only once per span.
The first check was needed because spans-within-macros seem to differ a lot and "fixing" them to the real location is not trivial (and the method that does this is private to another module). It also feels like there always will be an error on import, with the real file name, so not sure there's a point to re-emit the same error at macro use.
Fix#44953.
Implement RFC 1861: Extern types
A few notes :
- Type parameters are not supported. This was an unresolved question from the RFC. It is not clear how useful this feature is, and how variance should be treated. This can be added in a future PR.
- `size_of_val` / `align_of_val` can be called with extern types, and respectively return 0 and 1. This differs from the RFC, which specified that they should panic, but after discussion with @eddyb on IRC this seems like a better solution.
If/when a `DynSized` trait is added, this will be disallowed statically.
- Auto traits are not implemented by default, since the contents of extern types is unknown. This means extern types are `!Sync`, `!Send` and `!Freeze`. This seems like the correct behaviour to me.
Manual `unsafe impl Sync for Foo` is still possible.
- This PR allows extern type to be used as the tail of a struct, as described by the RFC :
```rust
extern {
type OpaqueTail;
}
#[repr(C)]
struct FfiStruct {
data: u8,
more_data: u32,
tail: OpaqueTail,
}
```
However this is undesirable, as the alignment of `tail` is unknown (the current PR assumes an alignment of 1). Unfortunately we can't prevent it in the general case as the tail could be a type parameter :
```rust
#[repr(C)]
struct FfiStruct<T: ?Sized> {
data: u8,
more_data: u32,
tail: T,
}
```
Adding a `DynSized` trait would solve this as well, by requiring tail fields to be bound by it.
- Despite being unsized, pointers to extern types are thin and can be casted from/to integers. However it is not possible to write a `null<T>() -> *const T` function which works with extern types, as I've explained here : https://github.com/rust-lang/rust/issues/43467#issuecomment-321678621
- Trait objects cannot be built from extern types. I intend to support it eventually, although how this interacts with `DynSized`/`size_of_val` is still unclear.
- The definition of `c_void` is unmodified
Use expect for current_dir on librustc/session mod
Reference bug https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=871638
Like described on the reference bug report:
~~~
$ mkdir dir
$ cd dir
$ rm -rf ../dir
$ RUST_BACKTRACE=1 rustc -C target-cpu=help
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'called `Result::unwrap()` on an `Err` value: Error { repr: Os { code: 2, message: "No such file or directory" } }', src/libcore/result.rs:837
stack backtrace:
1: 0x7f7d23970dda - <unknown>
2: 0x7f7d2398305f - <unknown>
3: 0x7f7d2397f8a5 - <unknown>
4: 0x7f7d2397ffc7 - std::panicking::rust_panic_with_hook::h109e116a3a861224
5: 0x7f7d2397fe54 - <unknown>
6: 0x7f7d2397fd79 - std::panicking::begin_panic_fmt::h26713cea9bce3ab0
7: 0x7f7d2397fd07 - rust_begin_unwind
8: 0x7f7d239cb41d - core::panicking::panic_fmt::hcfbb59eeb7f27f75
9: 0x7f7d20be63d3 - <unknown>
10: 0x7f7d20d6ebcc - rustc::session::build_session_::h7a3559f2373a5d05
11: 0x7f7d20d6dd7e - rustc::session::build_session_with_codemap::h68bc7bcd2f34eee4
12: 0x7f7d20d6d72c - rustc::session::build_session::h437fda3c327a8bde
13: 0x7f7d23d26030 - <rustc_driver::RustcDefaultCalls as rustc_driver::CompilerCalls<'a>>::no_input::h8047df7741757d1c
14: 0x7f7d23d21d27 - rustc_driver::run_compiler::hafe7bbfedf95a825
15: 0x7f7d23c57378 - <unknown>
16: 0x7f7d2398ae0a - __rust_maybe_catch_panic
17: 0x7f7d23c76fa8 - <unknown>
18: 0x7f7d2397eb74 - <unknown>
19: 0x7f7d1ed4f493 - start_thread
20: 0x7f7d23645afe - __clone
21: 0x0 - <unknown>
~~~
With this patch this will give instead:
~~~
error: Current directory is invalid: No such file or directory (os error 2)
~~~
Bump to 1.23 and update bootstrap
This commit updates the bootstrap compiler, bumps the version to 1.23, updates
Cargo, updates books, and updates crates.io dependencies
Avoid unnecessary copies of arguments that are simple bindings
Initially MIR differentiated between arguments and locals, which
introduced a need to add extra copies assigning the argument to a
local, even for simple bindings. This differentiation no longer exists,
but we're still creating those copies, bloating the MIR and LLVM IR we
emit.
Additionally, the current approach means that we create debug info for
both the incoming argument (marking it as an argument), and then
immediately shadow it a local that goes by the same name. This can be
confusing when using e.g. "info args" in gdb, or when e.g. a debugger
with a GUI displays the function arguments separately from the local
variables, especially when the binding is mutable, because the argument
doesn't change, while the local variable does.
Use 128 bit instead of Symbol for crate disambiguator
As discussed on gitter, this changes `crate_disambiguator` from Strings to what they are represented as, a 128 bit number.
There's also one bit I think also needs to change, but wasn't 100% sure how: [create_root_def](f338dba297/src/librustc/hir/map/definitions.rs (L468-L482)). Should I change `DefKey::root_parent_stable_hash` to accept `Fingerprint` as crate_disambiguator to quickly combine the hash of `crate_name` with the new 128 bit hash instead of a string for a disambiguator?
r? @michaelwoerister
EDIT: Are those 3 tests `mir-opt` failing, because the hash is different, because we calculate it a little bit differently (storing directly instead of hashing the hex-string representation)? Should it be updated like in #45319?
Improve diagnostic of E0119 with extern crate, try to print the conflicting impl.
Closes#27403.
Closes#23563.
Should improve #23980.
The diagnostic now looks like:
```
error[E0119]: conflicting implementations of trait `std::convert::Into<_>` for type `GenX<_>`:
--> $DIR/issue-27403.rs:15:1
|
15 | / impl<S> Into<S> for GenX<S> {
16 | | fn into(self) -> S {
17 | | self.inner
18 | | }
19 | | }
| |_^
|
= note: conflicting implementation in crate `core`:
- impl<T, U> std::convert::Into<U> for T
where U: std::convert::From<T>;
error: aborting due to previous error
```
