When #118865 started enforcing the `rustc::potential_query_instability` lint in
`rustc_codegen_llvm`, it added an exemption for this site, arguing that the
entries are only used to create a list of filenames that is later sorted.
However, the list of entries also gets traversed when creating the function
coverage records in LLVM IR, which may be sensitive to hash-based ordering.
This patch therefore changes `function_coverage_map` to use `FxIndexMap`, which
should avoid hash-based instability by iterating in insertion order.
rustc_lint: Enforce `rustc::potential_query_instability` lint
Stop allowing `rustc::potential_query_instability` on all of `rustc_lint` and instead allow it on a case-by-case basis if it is safe to do so. In this particular crate, all lints were safe to allow.
Part of https://github.com/rust-lang/rust/issues/84447 which is E-help-wanted.
Stop allowing `rustc::potential_query_instability` on all of
`rustc_lint` and instead allow it on a case-by-case basis if it is safe
to do so. In this particular crate, all lints were safe to allow.
Fix `<BoundConstness as Display>`
There was infinite recursion, which is not very good. I'm not sure what the best way to implement this is, I just did something that felt right.
r? `@fmease`
Move around the code responsible for decorating builtin diagnostics
This PR move the code responsible for decorating builtin diagnostics into a separate sub-module for ease of use and readability.
While my original intention was to also move the check-cfg unexpected logic in their own function I changed my mind after moving the match altogether. I can move those if desired.
Fixes https://github.com/rust-lang/rust/pull/119425#discussion_r1438446596
r? `@Nilstrieb`
Update to bitflags 2 in the compiler
This involves lots of breaking changes. There are two big changes that force changes. The first is that the bitflag types now don't automatically implement normal derive traits, so we need to derive them manually.
Additionally, bitflags now have a hidden inner type by default, which breaks our custom derives. The bitflags docs recommend using the impl form in these cases, which I did.
r? compiler
This involves lots of breaking changes. There are two big changes that
force changes. The first is that the bitflag types now don't
automatically implement normal derive traits, so we need to derive them
manually.
Additionally, bitflags now have a hidden inner type by default, which
breaks our custom derives. The bitflags docs recommend using the impl
form in these cases, which I did.
coverage: Prepare mappings separately from injecting statements
These two tasks historically needed to be interleaved, but after various recent changes (including #116046 and #116917) they can now be fully separated.
---
`@rustbot` label +A-code-coverage
These two tasks historically needed to be interleaved, but after various recent
changes (including #116046 and #116917) they can now be fully separated.
Fix invalid check-cfg Cargo feature diagnostic help
#118213 added specialized diagnostic for Cargo `feature` cfg. However when providing an empty `#[cfg(feature)]` condition the suggestion would suggest adding `feature` as a feature in `Cargo.toml` (wtf!).
This PR removes the invalid logic, which even brings a nice improvement.
```diff
--> $DIR/cargo-feature.rs:18:7
|
LL | #[cfg(feature)]
- | ^^^^^^^
+ | ^^^^^^^- help: specify a config value: `= "bitcode"`
|
= note: expected values for `feature` are: `bitcode`
- = help: consider defining `feature` as feature in `Cargo.toml`
```
The first commit add a test showing the bug and the second commit fixes the bug.
`@rustbot` label +F-check-cfg
Shrink span encoding further
Spans are now stored in a more compact form which cuts down on at least 1 byte per span (indirect/direct encoding) and at most 3 bytes per span (indirect/direct encoding, context byte, length byte). As a result, libcore metadata shrinks by 1.5MB.
I'm not a huge fan of the fairly manual encoding/decoding from bits implemented here. Something like Tokio's pack abstraction (https://github.com/tokio-rs/tokio/blob/master/tokio/src/util/bit.rs) might be desirable to cut down on some of the shifting etc. We might also say that this isn't worth doing :)
I took a look at copying the span encoding we use in memory (described [here](https://github.com/rust-lang/rust/blob/master/compiler/rustc_span/src/span_encoding.rs)). I think the format there makes a lot more sense for in-memory storage where prioritizing a fixed length (i.e., 4 or 8 bytes) is much more important. In metadata, it's much easier for us to have variable-length values, so there's less of a cliff if we don't quite fit. The bit packing scheme there would need changes to fit the varint scheme since it has a lot of all-1s patterns as the "relative offset" form.
Implement constant propagation on top of MIR SSA analysis
This implements the idea I proposed in https://github.com/rust-lang/rust/pull/110719#issuecomment-1718324700
Based on https://github.com/rust-lang/rust/pull/109597
The value numbering "GVN" pass formulates each rvalue that appears in MIR with an abstract form (the `Value` enum), and assigns an integer `VnIndex` to each. This abstract form can be used to deduplicate values, reusing an earlier local that holds the same value instead of recomputing. This part is proposed in #109597.
From this abstract representation, we can perform more involved simplifications, for example in https://github.com/rust-lang/rust/pull/111344.
With the abstract representation `Value`, we can also attempt to evaluate each to a constant using the interpreter. This builds a `VnIndex -> OpTy` map. From this map, we can opportunistically replace an operand or a rvalue with a constant if their value has an associated `OpTy`.
The most relevant commit is [Evaluated computed values to constants.](2767c4912e)"
r? `@oli-obk`
Spans are now stored in a more compact form which cuts down on at least
1 byte per span (indirect/direct encoding) and at most 3 bytes per span
(indirect/direct encoding, context byte, length byte). As a result,
libcore metadata shrinks by 1.5MB.
rustc_lint: Prevent triplication of various lints
Prevent triplication of various lints. The triplication happens because we run the same lint three times (or less in some cases):
* In `BuiltinCombinedPreExpansionLintPass`
* In `BuiltinCombinedEarlyLintPass`
* In `shallow_lint_levels_on()`
Only run the lints one time by checking the `lint_added_lints` bool.
Set your GitHub diff setting to ignore whitespaces changes when reviewing this PR, since I had to enclose a block inside an if.
Closes#73301
(I found this while exploring the code related to [this](https://github.com/rust-lang/rust/pull/119251#discussion_r1435677330) comment.)
