Implement jump threading MIR opt
This pass is an attempt to generalize `ConstGoto` and `SeparateConstSwitch` passes into a more complete jump threading pass.
This pass is rather heavy, as it performs a truncated backwards DFS on MIR starting from each `SwitchInt` terminator. This backwards DFS remains very limited, as it only walks through `Goto` terminators.
It is build to support constants and discriminants, and a propagating through a very limited set of operations.
The pass successfully manages to disentangle the `Some(x?)` use case and the DFA use case. It still needs a few tests before being ready.
coverage: Emit the filenames section before encoding per-function mappings
When embedding coverage information in LLVM IR (and ultimately in the resulting binary), there are two main things that each CGU needs to emit:
- A single `__llvm_covmap` record containing a coverage header, which mostly consists of a list of filenames used by the CGU's coverage mappings.
- Several `__llvm_covfun` records, one for each instrumented function, each of which contains the hash of the list of filenames in the header.
There is a kind of loose cyclic dependency between the two: we need the hash of the file table before we can emit the covfun records, but we need to traverse all of the instrumented functions in order to build the file table.
The existing code works by processing the individual functions first. It lazily adds filenames to the file table, and stores the mostly-complete function records in a temporary list. After this it hashes the file table, emits the header (containing the file table), and then uses the hash to emit all of the function records.
This PR reverses that order: first we traverse all of the functions (without trying to prepare their function records) to build a *complete* file table, and then emit it immediately. At this point we have the file table hash, so we can then proceed to build and emit all of the function records, without needing to store them in an intermediate list.
---
Along the way, this PR makes some necessary changes that are also worthwhile in their own right:
- We split `FunctionCoverage` into distinct collector/finished phases, which neatly avoids some borrow-checker hassles when extracting a function's final expression/mapping data.
- We avoid having to re-sort a function's mappings when preparing the list of filenames that it uses.
Uplift movability and mutability, the simple way
Just make type_ir a dependency of ast. This can be relaxed later if we want to make the dependency less heavy. Part of rust-lang/types-team#124.
r? `@lcnr` or `@jackh726`
Implement rustc part of RFC 3127 trim-paths
This PR implements (or at least tries to) [RFC 3127 trim-paths](https://github.com/rust-lang/rust/issues/111540), the rustc part. That is `-Zremap-path-scope` with all of it's components/scopes.
`@rustbot` label: +F-trim-paths
Normalize alloc-id in tests.
AllocIds are globally numbered in a rustc invocation. This makes them very sensitive to changes unrelated to what is being tested. This commit normalizes them by renumbering, in order of appearance in the output.
The renumbering allows to keep the identity, that a simple `allocN` wouldn't. This is useful when we have memory dumps.
cc `@saethlin`
r? `@oli-obk`
Remove cgu_reuse_tracker from Session
This removes a bit of global mutable state.
It will now miss post-lto cgu reuse when ThinLTO determines that a cgu doesn't get changed, but there weren't any tests for this anyway and a test for it would be fragile to the exact implementation of ThinLTO in LLVM.
Implement `-Clink-self-contained=-linker` opt out
This implements the `-Clink-self-contained` opt out necessary to switch to lld by changing rustc's defaults instead of cargo's.
Components that are enabled and disabled on the CLI are recorded, for the purpose of being merged with the ones which the target spec will declare (I'll open another PR for that tomorrow, for easier review).
For MCP510, we now check whether using the self-contained linker is disabled on the CLI. Right now it would only be sensible to with `-Zgcc-ld=lld` (and I'll add some checks that we don't both enable and disable a component on the CLI in a future PR), but the goal is to simplify adding the check of the target's enabled components here in the follow-up PRs.
r? `@petrochenkov`
Bring back generic parameters for indices in rustc_abi and make it compile on stable
This effectively reverses https://github.com/rust-lang/rust/pull/107163, allowing rust-analyzer to depend on this crate again,
It also moves some glob imports / expands them in the first commit because they made it more difficult for me to reason about things.
