The current behaviour introduced by commit
a50a3b8e31 would discard any
target features specified after crt-static (the only member of
RUSTC_SPECIFIC_FEATURES). This is because it returned instead of
continuing processing the next flag.
Signed-off-by: Jens Reidel <adrian@travitia.xyz>
Normally LLVM and rustc agree about what features are implied by
target-cpu, but for NVPTX, LLVM considers sm_* and ptx* features to be
exclusive, which makes sense for codegen purposes. But in Rust, we want
to think of them as:
sm_{sver} means that the target supports the hardware features of sver
ptx{pver} means the driver supports PTX ISA pver
Intrinsics usually require a minimum sm_{sver} and ptx{pver}.
Prior to this commit, -Ctarget-cpu=sm_70 would activate only sm_70 and
ptx60 (the minimum PTX version that supports sm_70, which maximizes
driver compatibility). With this commit, it also activates all the
implied target features (sm_20, ..., sm_62; ptx32, ..., ptx50).
This does change the logic a bit: previously, we didn't forward reverse
implications of negated features to the backend, instead relying on the backend
to handle the implication itself.
`rustc_span::symbol` defines some things that are re-exported from
`rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some
closely related things such as `Ident` and `kw`. So you can do `use
rustc_span::{Symbol, sym}` but you have to do `use
rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good
reason.
This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`,
and changes many `rustc_span::symbol::` qualifiers in `compiler/` to
`rustc_span::`. This is a 200+ net line of code reduction, mostly
because many files with two `use rustc_span` items can be reduced to
one.
Hir attributes
This PR needs some explanation, it's somewhat large.
- This is step one as described in https://github.com/rust-lang/compiler-team/issues/796. I've added a new `hir::Attribute` which is a lowered version of `ast::Attribute`. Right now, this has few concrete effects, however every place that after this PR parses a `hir::Attribute` should later get a pre-parsed attribute as described in https://github.com/rust-lang/compiler-team/issues/796 and transitively https://github.com/rust-lang/rust/issues/131229.
- an extension trait `AttributeExt` is added, which is implemented for both `ast::Attribute` and `hir::Atribute`. This makes `hir::Attributes` mostly compatible with code that used to parse `ast::Attribute`. All its methods are also added as inherent methods to avoid having to import the trait everywhere in the compiler.
- Incremental can not not hash `ast::Attribute` at all.
