This commit moves the actual code generation in the compiler behind a query
keyed by a codegen unit's name. This ended up entailing quite a few internal
refactorings to enable this, along with a few cut corners:
* The `OutputFilenames` structure is now tracked in the `TyCtxt` as it affects a
whole bunch of trans and such. This is now behind a query and threaded into
the construction of the `TyCtxt`.
* The `TyCtxt` now has a channel "out the back" intended to send data to worker
threads in rustc_trans. This is used as a sort of side effect of the codegen
query but morally what's happening here is the return value of the query
(currently unit but morally a path) is only valid once the background threads
have all finished.
* Dispatching work items to the codegen threads was refactored to only rely on
data in `TyCtxt`, which mostly just involved refactoring where data was
stored, moving it from the translation thread to the controller thread's
`CodegenContext` or the like.
* A new thread locals was introduced in trans to work around the query
system. This is used in the implementation of `assert_module_sources` which
looks like an artifact of the old query system and will presumably go away
once red/green is up and running.
This commit refactors the `collect_crate_translation_items` function to only
require the `TyCtxt` instead of a `SharedCrateContext` in preparation for
query-ifying this portion of trans.
Drop of arrays is now translated in trans::block in an ugly way that I
should clean up in a later PR, and does not handle panics in the middle
of an array drop, but this commit & PR are growing too big.
These changes are in the same commit to avoid needing to adapt
meth::trans_object_shim to the new scheme.
One codegen-units test is broken because we instantiate the shims even
when they are not needed. This will be fixed in the next PR.
This removes the Cell from AdtDef. Also, moving destructor validity
checking to on-demand (forced during item-type checking) ensures that
invalid destructors can't cause ICEs.
Fixes#38868.
Fixes#40132.
Give LLVM much more information about vtable pointers. Without the extra
information, LLVM has to be rather pessimistic about vtables, preventing
a number of obvious optimisations.
* Makes the vtable pointer argument noalias and readonly.
* Marks loads of the vtable pointer as nonnull.
* Marks load from the vtable with `!invariant.load` metadata.
Fixes#39992
According to the LLVM reference:
> A value of 0 or an omitted align argument means that the operation has
the ABI alignment for the target.
So loads/stores of fields of packed structs need to have their align set
to 1. Implement that by tracking the alignment of `LvalueRef`s.
Fixes#39376.
Fixes rebase fallout, makes code correct in presence of 128-bit constants.
This commit includes manual merge conflict resolution changes from a rebase by @est31.
