Skip to content

Commit 5dad6c2

Browse files
petrochenkovpetrochenkov
committed
Implement built-in attribute macro #[cfg_eval] 
1 parent 069e612 commit 5dad6c2

File tree

11 files changed

+259
-0
lines changed

11 files changed

+259
-0
lines changed

‎compiler/rustc_builtin_macros/src/cfg_eval.rs

Lines changed: 29 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,29 @@
1+
use crate::util::check_builtin_macro_attribute;
2+
3+
use rustc_ast::{self as ast, AstLike};
4+
use rustc_expand::base::{Annotatable, ExtCtxt};
5+
use rustc_expand::config::StripUnconfigured;
6+
use rustc_span::symbol::sym;
7+
use rustc_span::Span;
8+
9+
pub fn expand(
10+
ecx: &mut ExtCtxt<'_>,
11+
_span: Span,
12+
meta_item: &ast::MetaItem,
13+
item: Annotatable,
14+
) -> Vec<Annotatable> {
15+
check_builtin_macro_attribute(ecx, meta_item, sym::cfg_eval);
16+
17+
let mut visitor =
18+
StripUnconfigured { sess: ecx.sess, features: ecx.ecfg.features, modified: false };
19+
let mut item = visitor.fully_configure(item);
20+
if visitor.modified {
21+
// Erase the tokens if cfg-stripping modified the item
22+
// This will cause us to synthesize fake tokens
23+
// when `nt_to_tokenstream` is called on this item.
24+
if let Some(tokens) = item.tokens_mut() {
25+
*tokens = None;
26+
}
27+
}
28+
vec![item]
29+
}

‎compiler/rustc_builtin_macros/src/lib.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -24,6 +24,7 @@ mod asm;
2424
mod assert;
2525
mod cfg;
2626
mod cfg_accessible;
27+
mod cfg_eval;
2728
mod compile_error;
2829
mod concat;
2930
mod concat_idents;
@@ -89,6 +90,7 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
8990
register_attr! {
9091
bench: test::expand_bench,
9192
cfg_accessible: cfg_accessible::Expander,
93+
cfg_eval: cfg_eval::expand,
9294
derive: derive::Expander,
9395
global_allocator: global_allocator::expand,
9496
test: test::expand_test,

‎compiler/rustc_span/src/symbol.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -344,6 +344,7 @@ symbols! {
344344
cfg_attr,
345345
cfg_attr_multi,
346346
cfg_doctest,
347+
cfg_eval,
347348
cfg_panic,
348349
cfg_sanitize,
349350
cfg_target_feature,

‎library/core/src/macros/mod.rs

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1452,6 +1452,18 @@ pub(crate) mod builtin {
14521452
/* compiler built-in */
14531453
}
14541454

1455+
/// Expands all `#[cfg]` and `#[cfg_attr]` attributes in the code fragment it's applied to.
1456+
#[cfg(not(bootstrap))]
1457+
#[unstable(
1458+
feature = "cfg_eval",
1459+
issue = "82679",
1460+
reason = "`cfg_eval` is a recently implemented feature"
1461+
)]
1462+
#[rustc_builtin_macro]
1463+
pub macro cfg_eval($($tt:tt)*) {
1464+
/* compiler built-in */
1465+
}
1466+
14551467
/// Unstable implementation detail of the `rustc` compiler, do not use.
14561468
#[rustc_builtin_macro]
14571469
#[stable(feature = "rust1", since = "1.0.0")]

‎library/core/src/prelude/v1.rs

Lines changed: 9 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -81,3 +81,12 @@ pub use crate::macros::builtin::derive;
8181
)]
8282
#[doc(no_inline)]
8383
pub use crate::macros::builtin::cfg_accessible;
84+
85+
#[cfg(not(bootstrap))]
86+
#[unstable(
87+
feature = "cfg_eval",
88+
issue = "82679",
89+
reason = "`cfg_eval` is a recently implemented feature"
90+
)]
91+
#[doc(no_inline)]
92+
pub use crate::macros::builtin::cfg_eval;

‎library/std/src/lib.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -234,6 +234,7 @@
234234
#![feature(box_syntax)]
235235
#![feature(c_variadic)]
236236
#![feature(cfg_accessible)]
237+
#![cfg_attr(not(bootstrap), feature(cfg_eval))]
237238
#![feature(cfg_target_has_atomic)]
238239
#![feature(cfg_target_thread_local)]
239240
#![feature(char_error_internals)]

‎library/std/src/prelude/v1.rs

Lines changed: 9 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -67,6 +67,15 @@ pub use core::prelude::v1::derive;
6767
#[doc(hidden)]
6868
pub use core::prelude::v1::cfg_accessible;
6969

70+
#[cfg(not(bootstrap))]
71+
#[unstable(
72+
feature = "cfg_eval",
73+
issue = "82679",
74+
reason = "`cfg_eval` is a recently implemented feature"
75+
)]
76+
#[doc(hidden)]
77+
pub use core::prelude::v1::cfg_eval;
78+
7079
// The file so far is equivalent to src/libcore/prelude/v1.rs,
7180
// and below to src/liballoc/prelude.rs.
7281
// Those files are duplicated rather than using glob imports

‎src/test/ui/proc-macro/cfg-eval-fail.rs

Lines changed: 9 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,9 @@
1+
#![feature(cfg_eval)]
2+
#![feature(stmt_expr_attributes)]
3+
4+
fn main() {
5+
let _ = #[cfg_eval] #[cfg(FALSE)] 0;
6+
//~^ ERROR removing an expression is not supported in this position
7+
//~| ERROR removing an expression is not supported in this position
8+
//~| ERROR removing an expression is not supported in this position
9+
}

‎src/test/ui/proc-macro/cfg-eval-fail.stderr

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,20 @@
1+
error: removing an expression is not supported in this position
2+
--> $DIR/cfg-eval-fail.rs:5:25
3+
|
4+
LL | let _ = #[cfg_eval] #[cfg(FALSE)] 0;
5+
| ^^^^^^^^^^^^^
6+
7+
error: removing an expression is not supported in this position
8+
--> $DIR/cfg-eval-fail.rs:5:25
9+
|
10+
LL | let _ = #[cfg_eval] #[cfg(FALSE)] 0;
11+
| ^^^^^^^^^^^^^
12+
13+
error: removing an expression is not supported in this position
14+
--> $DIR/cfg-eval-fail.rs:5:25
15+
|
16+
LL | let _ = #[cfg_eval] #[cfg(FALSE)] 0;
17+
| ^^^^^^^^^^^^^
18+
19+
error: aborting due to 3 previous errors
20+

‎src/test/ui/proc-macro/cfg-eval.rs

Lines changed: 32 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,32 @@
1+
// check-pass
2+
// compile-flags: -Z span-debug
3+
// aux-build:test-macros.rs
4+
5+
#![feature(cfg_eval)]
6+
#![feature(proc_macro_hygiene)]
7+
#![feature(stmt_expr_attributes)]
8+
9+
#![no_std] // Don't load unnecessary hygiene information from std
10+
extern crate std;
11+
12+
#[macro_use]
13+
extern crate test_macros;
14+
15+
#[cfg_eval]
16+
#[print_attr]
17+
struct S1 {
18+
#[cfg(FALSE)]
19+
field_false: u8,
20+
#[cfg(all(/*true*/))]
21+
#[cfg_attr(FALSE, unknown_attr)]
22+
#[cfg_attr(all(/*true*/), allow())]
23+
field_true: u8,
24+
}
25+
26+
#[cfg_eval]
27+
#[cfg(FALSE)]
28+
struct S2 {}
29+
30+
fn main() {
31+
let _ = #[cfg_eval] #[print_attr](#[cfg(FALSE)] 0, #[cfg(all(/*true*/))] 1);
32+
}

‎src/test/ui/proc-macro/cfg-eval.stdout

Lines changed: 135 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,135 @@
1+
PRINT-ATTR INPUT (DISPLAY): struct S1 { #[cfg(all())] #[allow()] field_true : u8, }
2+
PRINT-ATTR INPUT (DEBUG): TokenStream [
3+
Ident {
4+
ident: "struct",
5+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
6+
},
7+
Ident {
8+
ident: "S1",
9+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
10+
},
11+
Group {
12+
delimiter: Brace,
13+
stream: TokenStream [
14+
Punct {
15+
ch: '#',
16+
spacing: Alone,
17+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
18+
},
19+
Group {
20+
delimiter: Bracket,
21+
stream: TokenStream [
22+
Ident {
23+
ident: "cfg",
24+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
25+
},
26+
Group {
27+
delimiter: Parenthesis,
28+
stream: TokenStream [
29+
Ident {
30+
ident: "all",
31+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
32+
},
33+
Group {
34+
delimiter: Parenthesis,
35+
stream: TokenStream [],
36+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
37+
},
38+
],
39+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
40+
},
41+
],
42+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
43+
},
44+
Punct {
45+
ch: '#',
46+
spacing: Alone,
47+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
48+
},
49+
Group {
50+
delimiter: Bracket,
51+
stream: TokenStream [
52+
Ident {
53+
ident: "allow",
54+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
55+
},
56+
Group {
57+
delimiter: Parenthesis,
58+
stream: TokenStream [],
59+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
60+
},
61+
],
62+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
63+
},
64+
Ident {
65+
ident: "field_true",
66+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
67+
},
68+
Punct {
69+
ch: ':',
70+
spacing: Alone,
71+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
72+
},
73+
Ident {
74+
ident: "u8",
75+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
76+
},
77+
Punct {
78+
ch: ',',
79+
spacing: Alone,
80+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
81+
},
82+
],
83+
span: $DIR/cfg-eval.rs:17:1: 24:2 (#0),
84+
},
85+
]
86+
PRINT-ATTR INPUT (DISPLAY): (#[cfg(all())] 1,)
87+
PRINT-ATTR INPUT (DEBUG): TokenStream [
88+
Group {
89+
delimiter: Parenthesis,
90+
stream: TokenStream [
91+
Punct {
92+
ch: '#',
93+
spacing: Alone,
94+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
95+
},
96+
Group {
97+
delimiter: Bracket,
98+
stream: TokenStream [
99+
Ident {
100+
ident: "cfg",
101+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
102+
},
103+
Group {
104+
delimiter: Parenthesis,
105+
stream: TokenStream [
106+
Ident {
107+
ident: "all",
108+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
109+
},
110+
Group {
111+
delimiter: Parenthesis,
112+
stream: TokenStream [],
113+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
114+
},
115+
],
116+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
117+
},
118+
],
119+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
120+
},
121+
Literal {
122+
kind: Integer,
123+
symbol: "1",
124+
suffix: None,
125+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
126+
},
127+
Punct {
128+
ch: ',',
129+
spacing: Alone,
130+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
131+
},
132+
],
133+
span: $DIR/cfg-eval.rs:31:38: 31:80 (#0),
134+
},
135+
]

0 commit comments

Comments
 (0)