1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
|
//! Defines language items.
//!
//! Language items are items that represent concepts intrinsic to the language
//! itself. Examples are:
//!
//! * Traits that specify "kinds"; e.g., `Sync`, `Send`.
//! * Traits that represent operators; e.g., `Add`, `Sub`, `Index`.
//! * Functions called by the compiler itself.
pub use self::LangItem::*;
use crate::def_id::DefId;
use crate::Target;
use rustc_ast::ast;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_macros::HashStable_Generic;
use rustc_span::symbol::{sym, Symbol};
use rustc_span::Span;
use lazy_static::lazy_static;
// The actual lang items defined come at the end of this file in one handy table.
// So you probably just want to nip down to the end.
macro_rules! language_item_table {
(
$( $variant:ident, $name:expr, $method:ident, $target:path; )*
) => {
enum_from_u32! {
/// A representation of all the valid language items in Rust.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
pub enum LangItem {
$($variant,)*
}
}
impl LangItem {
/// Returns the `name` in `#[lang = "$name"]`.
/// For example, `LangItem::EqTraitLangItem`,
/// that is `#[lang = "eq"]` would result in `"eq"`.
pub fn name(self) -> &'static str {
match self {
$( $variant => $name, )*
}
}
}
#[derive(HashStable_Generic)]
pub struct LanguageItems {
/// Mappings from lang items to their possibly found `DefId`s.
/// The index corresponds to the order in `LangItem`.
pub items: Vec<Option<DefId>>,
/// Lang items that were not found during collection.
pub missing: Vec<LangItem>,
}
impl LanguageItems {
/// Construct an empty collection of lang items and no missing ones.
pub fn new() -> Self {
fn init_none(_: LangItem) -> Option<DefId> { None }
Self {
items: vec![$(init_none($variant)),*],
missing: Vec::new(),
}
}
/// Returns the mappings to the possibly found `DefId`s for each lang item.
pub fn items(&self) -> &[Option<DefId>] {
&*self.items
}
/// Requires that a given `LangItem` was bound and returns the corresponding `DefId`.
/// If it wasn't bound, e.g. due to a missing `#[lang = "<it.name()>"]`,
/// returns an error message as a string.
pub fn require(&self, it: LangItem) -> Result<DefId, String> {
self.items[it as usize].ok_or_else(|| format!("requires `{}` lang_item", it.name()))
}
$(
/// Returns the corresponding `DefId` for the lang item
#[doc = $name]
/// if it exists.
#[allow(dead_code)]
pub fn $method(&self) -> Option<DefId> {
self.items[$variant as usize]
}
)*
}
lazy_static! {
/// A mapping from the name of the lang item to its order and the form it must be of.
pub static ref ITEM_REFS: FxHashMap<&'static str, (usize, Target)> = {
let mut item_refs = FxHashMap::default();
$( item_refs.insert($name, ($variant as usize, $target)); )*
item_refs
};
}
// End of the macro
}
}
impl<CTX> HashStable<CTX> for LangItem {
fn hash_stable(&self, _: &mut CTX, hasher: &mut StableHasher) {
::std::hash::Hash::hash(self, hasher);
}
}
/// Extracts the first `lang = "$name"` out of a list of attributes.
/// The attributes `#[panic_handler]` and `#[alloc_error_handler]`
/// are also extracted out when found.
pub fn extract(attrs: &[ast::Attribute]) -> Option<(Symbol, Span)> {
attrs.iter().find_map(|attr| {
Some(match attr {
_ if attr.check_name(sym::lang) => (attr.value_str()?, attr.span),
_ if attr.check_name(sym::panic_handler) => (sym::panic_impl, attr.span),
_ if attr.check_name(sym::alloc_error_handler) => (sym::oom, attr.span),
_ => return None,
})
})
}
language_item_table! {
// Variant name, Name, Method name, Target;
BoolImplItem, "bool", bool_impl, Target::Impl;
CharImplItem, "char", char_impl, Target::Impl;
StrImplItem, "str", str_impl, Target::Impl;
SliceImplItem, "slice", slice_impl, Target::Impl;
SliceU8ImplItem, "slice_u8", slice_u8_impl, Target::Impl;
StrAllocImplItem, "str_alloc", str_alloc_impl, Target::Impl;
SliceAllocImplItem, "slice_alloc", slice_alloc_impl, Target::Impl;
SliceU8AllocImplItem, "slice_u8_alloc", slice_u8_alloc_impl, Target::Impl;
ConstPtrImplItem, "const_ptr", const_ptr_impl, Target::Impl;
MutPtrImplItem, "mut_ptr", mut_ptr_impl, Target::Impl;
ConstSlicePtrImplItem, "const_slice_ptr", const_slice_ptr_impl, Target::Impl;
MutSlicePtrImplItem, "mut_slice_ptr", mut_slice_ptr_impl, Target::Impl;
I8ImplItem, "i8", i8_impl, Target::Impl;
I16ImplItem, "i16", i16_impl, Target::Impl;
I32ImplItem, "i32", i32_impl, Target::Impl;
I64ImplItem, "i64", i64_impl, Target::Impl;
I128ImplItem, "i128", i128_impl, Target::Impl;
IsizeImplItem, "isize", isize_impl, Target::Impl;
U8ImplItem, "u8", u8_impl, Target::Impl;
U16ImplItem, "u16", u16_impl, Target::Impl;
U32ImplItem, "u32", u32_impl, Target::Impl;
U64ImplItem, "u64", u64_impl, Target::Impl;
U128ImplItem, "u128", u128_impl, Target::Impl;
UsizeImplItem, "usize", usize_impl, Target::Impl;
F32ImplItem, "f32", f32_impl, Target::Impl;
F64ImplItem, "f64", f64_impl, Target::Impl;
F32RuntimeImplItem, "f32_runtime", f32_runtime_impl, Target::Impl;
F64RuntimeImplItem, "f64_runtime", f64_runtime_impl, Target::Impl;
SizedTraitLangItem, "sized", sized_trait, Target::Trait;
UnsizeTraitLangItem, "unsize", unsize_trait, Target::Trait;
// trait injected by #[derive(PartialEq)], (i.e. "Partial EQ").
StructuralPeqTraitLangItem, "structural_peq", structural_peq_trait, Target::Trait;
// trait injected by #[derive(Eq)], (i.e. "Total EQ"; no, I will not apologize).
StructuralTeqTraitLangItem, "structural_teq", structural_teq_trait, Target::Trait;
CopyTraitLangItem, "copy", copy_trait, Target::Trait;
CloneTraitLangItem, "clone", clone_trait, Target::Trait;
SyncTraitLangItem, "sync", sync_trait, Target::Trait;
DiscriminantKindTraitLangItem,"discriminant_kind", discriminant_kind_trait, Target::Trait;
FreezeTraitLangItem, "freeze", freeze_trait, Target::Trait;
DropTraitLangItem, "drop", drop_trait, Target::Trait;
CoerceUnsizedTraitLangItem, "coerce_unsized", coerce_unsized_trait, Target::Trait;
DispatchFromDynTraitLangItem,"dispatch_from_dyn", dispatch_from_dyn_trait, Target::Trait;
AddTraitLangItem, "add", add_trait, Target::Trait;
SubTraitLangItem, "sub", sub_trait, Target::Trait;
MulTraitLangItem, "mul", mul_trait, Target::Trait;
DivTraitLangItem, "div", div_trait, Target::Trait;
RemTraitLangItem, "rem", rem_trait, Target::Trait;
NegTraitLangItem, "neg", neg_trait, Target::Trait;
NotTraitLangItem, "not", not_trait, Target::Trait;
BitXorTraitLangItem, "bitxor", bitxor_trait, Target::Trait;
BitAndTraitLangItem, "bitand", bitand_trait, Target::Trait;
BitOrTraitLangItem, "bitor", bitor_trait, Target::Trait;
ShlTraitLangItem, "shl", shl_trait, Target::Trait;
ShrTraitLangItem, "shr", shr_trait, Target::Trait;
AddAssignTraitLangItem, "add_assign", add_assign_trait, Target::Trait;
SubAssignTraitLangItem, "sub_assign", sub_assign_trait, Target::Trait;
MulAssignTraitLangItem, "mul_assign", mul_assign_trait, Target::Trait;
DivAssignTraitLangItem, "div_assign", div_assign_trait, Target::Trait;
RemAssignTraitLangItem, "rem_assign", rem_assign_trait, Target::Trait;
BitXorAssignTraitLangItem, "bitxor_assign", bitxor_assign_trait, Target::Trait;
BitAndAssignTraitLangItem, "bitand_assign", bitand_assign_trait, Target::Trait;
BitOrAssignTraitLangItem, "bitor_assign", bitor_assign_trait, Target::Trait;
ShlAssignTraitLangItem, "shl_assign", shl_assign_trait, Target::Trait;
ShrAssignTraitLangItem, "shr_assign", shr_assign_trait, Target::Trait;
IndexTraitLangItem, "index", index_trait, Target::Trait;
IndexMutTraitLangItem, "index_mut", index_mut_trait, Target::Trait;
UnsafeCellTypeLangItem, "unsafe_cell", unsafe_cell_type, Target::Struct;
VaListTypeLangItem, "va_list", va_list, Target::Struct;
DerefTraitLangItem, "deref", deref_trait, Target::Trait;
DerefMutTraitLangItem, "deref_mut", deref_mut_trait, Target::Trait;
ReceiverTraitLangItem, "receiver", receiver_trait, Target::Trait;
FnTraitLangItem, "fn", fn_trait, Target::Trait;
FnMutTraitLangItem, "fn_mut", fn_mut_trait, Target::Trait;
FnOnceTraitLangItem, "fn_once", fn_once_trait, Target::Trait;
FutureTraitLangItem, "future_trait", future_trait, Target::Trait;
GeneratorStateLangItem, "generator_state", gen_state, Target::Enum;
GeneratorTraitLangItem, "generator", gen_trait, Target::Trait;
UnpinTraitLangItem, "unpin", unpin_trait, Target::Trait;
PinTypeLangItem, "pin", pin_type, Target::Struct;
// Don't be fooled by the naming here: this lang item denotes `PartialEq`, not `Eq`.
EqTraitLangItem, "eq", eq_trait, Target::Trait;
PartialOrdTraitLangItem, "partial_ord", partial_ord_trait, Target::Trait;
// A number of panic-related lang items. The `panic` item corresponds to
// divide-by-zero and various panic cases with `match`. The
// `panic_bounds_check` item is for indexing arrays.
//
// The `begin_unwind` lang item has a predefined symbol name and is sort of
// a "weak lang item" in the sense that a crate is not required to have it
// defined to use it, but a final product is required to define it
// somewhere. Additionally, there are restrictions on crates that use a weak
// lang item, but do not have it defined.
PanicFnLangItem, "panic", panic_fn, Target::Fn;
PanicBoundsCheckFnLangItem, "panic_bounds_check", panic_bounds_check_fn, Target::Fn;
PanicInfoLangItem, "panic_info", panic_info, Target::Struct;
PanicLocationLangItem, "panic_location", panic_location, Target::Struct;
PanicImplLangItem, "panic_impl", panic_impl, Target::Fn;
// Libstd panic entry point. Necessary for const eval to be able to catch it
BeginPanicFnLangItem, "begin_panic", begin_panic_fn, Target::Fn;
ExchangeMallocFnLangItem, "exchange_malloc", exchange_malloc_fn, Target::Fn;
BoxFreeFnLangItem, "box_free", box_free_fn, Target::Fn;
DropInPlaceFnLangItem, "drop_in_place", drop_in_place_fn, Target::Fn;
OomLangItem, "oom", oom, Target::Fn;
AllocLayoutLangItem, "alloc_layout", alloc_layout, Target::Struct;
StartFnLangItem, "start", start_fn, Target::Fn;
EhPersonalityLangItem, "eh_personality", eh_personality, Target::Fn;
EhCatchTypeinfoLangItem, "eh_catch_typeinfo", eh_catch_typeinfo, Target::Static;
OwnedBoxLangItem, "owned_box", owned_box, Target::Struct;
PhantomDataItem, "phantom_data", phantom_data, Target::Struct;
ManuallyDropItem, "manually_drop", manually_drop, Target::Struct;
MaybeUninitLangItem, "maybe_uninit", maybe_uninit, Target::Union;
// Align offset for stride != 1; must not panic.
AlignOffsetLangItem, "align_offset", align_offset_fn, Target::Fn;
TerminationTraitLangItem, "termination", termination, Target::Trait;
TryTraitLangItem, "try", try_trait, Target::Trait;
}
|
