bee074f032
rustc: keep upvars tupled in {Closure,Generator}Substs.
Previously, each closure/generator capture's (aka "upvar") type was tracked as one "synthetic" type parameter in the closure/generator substs, and figuring out where the parent `fn`'s generics end and the synthetics start involved slicing at `tcx.generics_of(def_id).parent_count`.
Needing to query `generics_of` limited @davidtwco (who wants to compute some `TypeFlags` differently for parent generics vs upvars, and `TyCtxt` is not available there), which is how I got started on this, but it's also possible that the `generics_of` queries are slowing down `{Closure,Generator}Substs` methods.
To give an example, for a `foo::<T, U>::{closure#0}` with captures `x: X` and `y: Y`, substs are:
* before this PR: `[T, U, /*kind*/, /*signature*/, X, Y]`
* after this PR: `[T, U, /*kind*/, /*signature*/, (X, Y)]`
You can see that, with this PR, no matter how many captures, the last 3 entries in the substs (or 5 for a generator) are always the "synthetic" ones, with the last one being the tuple of capture types.
r? @nikomatsakis cc @Zoxc
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| .. | ||
| back | ||
| debuginfo | ||
| llvm | ||
| abi.rs | ||
| allocator.rs | ||
| asm.rs | ||
| attributes.rs | ||
| base.rs | ||
| build.rs | ||
| builder.rs | ||
| callee.rs | ||
| Cargo.toml | ||
| common.rs | ||
| consts.rs | ||
| context.rs | ||
| declare.rs | ||
| intrinsic.rs | ||
| lib.rs | ||
| llvm_util.rs | ||
| metadata.rs | ||
| mono_item.rs | ||
| README.md | ||
| type_.rs | ||
| type_of.rs | ||
| va_arg.rs | ||
| value.rs | ||
The codegen crate contains the code to convert from MIR into LLVM IR,
and then from LLVM IR into machine code. In general it contains code
that runs towards the end of the compilation process.
For more information about how codegen works, see the rustc dev guide.