@@ -30,7 +30,7 @@ pub type FxHashMap<K, V> = HashMap<K, V>; // re-export for use in src/librustdoc
3030/// This integer is incremented with every breaking change to the API,
3131/// and is returned along with the JSON blob as [`Crate::format_version`].
3232/// Consuming code should assert that this value matches the format version(s) that it supports.
33- pub const FORMAT_VERSION : u32 = 43 ;
33+ pub const FORMAT_VERSION : u32 = 44 ;
3434
3535/// The root of the emitted JSON blob.
3636///
@@ -52,11 +52,67 @@ pub struct Crate {
5252pub paths : HashMap < Id , ItemSummary > ,
5353 /// Maps `crate_id` of items to a crate name and html_root_url if it exists.
5454pub external_crates : HashMap < u32 , ExternalCrate > ,
55+ /// Information about the target for which this documentation was generated
56+ pub target : Target ,
5557 /// A single version number to be used in the future when making backwards incompatible changes
5658/// to the JSON output.
5759pub format_version : u32 ,
5860}
5961
62+ /// Information about a target
63+ #[ derive( Clone , Debug , PartialEq , Eq , Serialize , Deserialize ) ]
64+ pub struct Target {
65+ /// The target triple for which this documentation was generated
66+ pub triple : String ,
67+ /// A list of features valid for use in `#[target_feature]` attributes
68+ /// for the target where this rustdoc JSON was generated.
69+ pub target_features : Vec < TargetFeature > ,
70+ }
71+
72+ /// Information about a target feature.
73+ ///
74+ /// Rust target features are used to influence code generation, especially around selecting
75+ /// instructions which are not universally supported by the target architecture.
76+ ///
77+ /// Target features are commonly enabled by the [`#[target_feature]` attribute][1] to influence code
78+ /// generation for a particular function, and less commonly enabled by compiler options like
79+ /// `-Ctarget-feature` or `-Ctarget-cpu`. Targets themselves automatically enable certain target
80+ /// features by default, for example because the target's ABI specification requires saving specific
81+ /// registers which only exist in an architectural extension.
82+ ///
83+ /// Target features can imply other target features: for example, x86-64 `avx2` implies `avx`, and
84+ /// aarch64 `sve2` implies `sve`, since both of these architectural extensions depend on their
85+ /// predecessors.
86+ ///
87+ /// Target features can be probed at compile time by [`#[cfg(target_feature)]`][2] or `cfg!(…)`
88+ /// conditional compilation to determine whether a target feature is enabled in a particular
89+ /// context.
90+ ///
91+ /// [1]: https://doc.rust-lang.org/stable/reference/attributes/codegen.html#the-target_feature-attribute
92+ /// [2]: https://doc.rust-lang.org/reference/conditional-compilation.html#target_feature
93+ #[ derive( Clone , Debug , PartialEq , Eq , Serialize , Deserialize ) ]
94+ pub struct TargetFeature {
95+ /// The name of this target feature.
96+ pub name : String ,
97+ /// Other target features which are implied by this target feature, if any.
98+ pub implies_features : Vec < String > ,
99+ /// If this target feature is unstable, the name of the associated language feature gate.
100+ pub unstable_feature_gate : Option < String > ,
101+ /// Whether this feature is globally enabled for this compilation session.
102+ ///
103+ /// Target features can be globally enabled implicitly as a result of the target's definition.
104+ /// For example, x86-64 hardware floating point ABIs require saving x87 and SSE2 registers,
105+ /// which in turn requires globally enabling the `x87` and `sse2` target features so that the
106+ /// generated machine code conforms to the target's ABI.
107+ ///
108+ /// Target features can also be globally enabled explicitly as a result of compiler flags like
109+ /// [`-Ctarget-feature`][1] or [`-Ctarget-cpu`][2].
110+ ///
111+ /// [1]: https://doc.rust-lang.org/beta/rustc/codegen-options/index.html#target-feature
112+ /// [2]: https://doc.rust-lang.org/beta/rustc/codegen-options/index.html#target-cpu
113+ pub globally_enabled : bool ,
114+ }
115+
60116/// Metadata of a crate, either the same crate on which `rustdoc` was invoked, or its dependency.
61117#[ derive( Clone , Debug , PartialEq , Eq , Hash , Serialize , Deserialize ) ]
62118pub struct ExternalCrate {
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