We also sever syntax's dependency on rustc_target as a result.
This should slightly improve pipe-lining.
Moreover, some cleanup is done in related code.
Remove `InternedString`
This PR removes `InternedString` by converting all occurrences to `Symbol`. There are a handful of places that need to use the symbol chars instead of the symbol index, e.g. for stable sorting; local conversions `LocalInternedString` is used in those places.
r? @eddyb
It's a full conversion, except in `DefKey::compute_stable_hash()` where
a `Symbol` now is converted to an `InternedString` before being hashed.
This was necessary to avoid test failures.
Closure types have been moved to the namespace where they
are defined, and both closure and generator type names now
include the disambiguator.
This fixes an exception when lldb prints nested closures.
Fixes#57822
This commit brings in a number of minor updates for rustc's support for
the wasm target which has changed in the LLVM 9 update. Notable updates
include:
* The compiler now no longer manually inserts the `producers` section,
instead relying on LLVM to do so. LLVM uses the `llvm.ident` metadata
for the `processed-by` directive (which is now emitted on the wasm
target in this PR) and it uses debuginfo to figure out what `language`
to put in the `producers` section.
* Threaded WebAssembly code now requires different flags to be passed
with LLD. In LLD we now pass:
* `--shared-memory` - required since objects are compiled with
atomics. This also means that the generated memory will be marked as
`shared`.
* `--max-memory=1GB` - required with the `--shared-memory` argument
since shared memories in WebAssembly must have a maximum size. The
1GB number is intended to be a conservative estimate for rustc, but
it should be overridable with `-C link-arg` if necessary.
* `--passive-segments` - this has become the default for multithreaded
memory, but when compiling a threaded module all data segments need
to be marked as passive to ensure they don't re-initialize memory
for each thread. This will also cause LLD to emit a synthetic
function to initialize memory which users will have to arrange to
call.
* The `__heap_base` and `__data_end` globals are explicitly exported
since they're now hidden by default due to the `--export` flags we
pass to LLD.
The commit should have changed comments as well.
At the time of writting, it passes the tidy and check tool.
Revisions asked by eddyb :
- Renamed of all the occurences of {visit/super}_mir
- Renamed test structures `CachedMir` to `Cached`
Fixing the missing import on `AggregateKind`
Avoid symbol interning in `file_metadata`.
This commit changes `created_files` so it uses strings directly as keys,
rather than symbols derived from the strings. This avoids the cost of
having to do the hash table lookups to produce the symbols from the
strings.
The commit also uses `entry` to avoid doing a repeated hash table lookup
(`get` + `insert`).
Note that PR #60467 improved this code somewhat; this is a further
improvement.
r? @davidtwco
cff075009 made LLVM emit
less debuginfo when compiling with "line-tables-only". The change
was essentially correct but the reduced amount of debuginfo broke
a number of tools.
This commit reverts the change so we get back the old behavior,
until we figure out how to do this properly and give external
tools to adapt to the new format.
See https://github.com/rust-lang/rust/issues/60020 for more info.
This commit changes `created_files` so it uses strings directly as keys,
rather than symbols derived from the strings. This avoids the cost of
having to do the hash table lookups to produce the symbols from the
strings.
The commit also uses `entry` to avoid doing a repeated hash table lookup
(`get` + `insert`).
Note that PR #60467 improved this code somewhat; this is a further
improvement.
Multi-variant layouts for generators
This allows generators to overlap fields using variants, but doesn't do any such overlapping yet. It creates one variant for every state of the generator (unresumed, returned, panicked, plus one for every yield), and puts every stored local in each of the yield-point variants.
Required for optimizing generator layouts (#52924).
There was quite a lot of refactoring needed for this change. I've done my best in later commits to eliminate assumptions in the code that only certain kinds of types are multi-variant, and to centralize knowledge of the inner mechanics of generators in as few places as possible.
This change also emits debuginfo about the fields contained in each variant, as well as preserving debuginfo about stored locals while running in the generator.
Also, fixes#59972.
Future work:
- Use this change for an optimization pass that actually overlaps locals within the generator struct (#52924)
- In the type layout fields, don't include locals that are uninitialized for a particular variant, so miri and UB sanitizers can check our memory (see https://github.com/rust-lang/rust/issues/59972#issuecomment-483058172)
- Preserve debuginfo scopes across generator yield points
`file_metadata_raw` interns the strings `"<unknown>"` and `""` very
frequently. This commit avoids that, which reduces the number of symbols
interned significantly and reduces instruction counts by up to 0.5% on
some workloads.
