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AmanieuAmanieu
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Merge pull request #598 from Amjad50/remove_weak-intrinsics
Apply `weak` attributes to all intrinsics
2 parents dfe778f + 8a7ba9a commit ab63499

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5 files changed

+38
-139
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5 files changed

+38
-139
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‎Cargo.toml

-11
Original file line numberDiff line numberDiff line change
@@ -70,17 +70,6 @@ rustc-dep-of-std = ['compiler-builtins', 'core']
7070
# are not normally public but are required by the `testcrate`
7171
public-test-deps = []
7272

73-
# Marks all intrinsics functions with weak linkage so that they can be
74-
# replaced at link time by another implementation. This is particularly useful
75-
# for mixed Rust/C++ binaries that want to use the C++ intrinsics, otherwise
76-
# linking against the Rust stdlib will replace those from the compiler-rt
77-
# library.
78-
#
79-
# Unlike the "c" feature, the intrinsics are still provided by the Rust
80-
# implementations and each will be used unless a stronger symbol replaces
81-
# it during linking.
82-
weak-intrinsics = []
83-
8473
[[example]]
8574
name = "intrinsics"
8675
required-features = ["compiler-builtins"]

‎src/arm.rs

-18
Original file line numberDiff line numberDiff line change
@@ -20,7 +20,6 @@ macro_rules! bl {
2020
intrinsics! {
2121
// NOTE This function and the ones below are implemented using assembly because they are using a
2222
// custom calling convention which can't be implemented using a normal Rust function.
23-
#[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
2423
#[naked]
2524
#[cfg(not(target_env = "msvc"))]
2625
pub unsafe extern "C" fn __aeabi_uidivmod() {
@@ -36,7 +35,6 @@ intrinsics! {
3635
);
3736
}
3837

39-
#[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
4038
#[naked]
4139
pub unsafe extern "C" fn __aeabi_uldivmod() {
4240
core::arch::asm!(
@@ -53,7 +51,6 @@ intrinsics! {
5351
);
5452
}
5553

56-
#[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
5754
#[naked]
5855
pub unsafe extern "C" fn __aeabi_idivmod() {
5956
core::arch::asm!(
@@ -67,7 +64,6 @@ intrinsics! {
6764
);
6865
}
6966

70-
#[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
7167
#[naked]
7268
pub unsafe extern "C" fn __aeabi_ldivmod() {
7369
core::arch::asm!(
@@ -84,17 +80,13 @@ intrinsics! {
8480
);
8581
}
8682

87-
// The following functions use weak linkage to allow users to override
88-
// with custom implementation.
8983
// FIXME: The `*4` and `*8` variants should be defined as aliases.
9084

91-
#[weak]
9285
#[cfg(not(target_os = "ios"))]
9386
pub unsafe extern "aapcs" fn __aeabi_memcpy(dest: *mut u8, src: *const u8, n: usize) {
9487
crate::mem::memcpy(dest, src, n);
9588
}
9689

97-
#[weak]
9890
#[cfg(not(target_os = "ios"))]
9991
pub unsafe extern "aapcs" fn __aeabi_memcpy4(dest: *mut u8, src: *const u8, n: usize) {
10092
// We are guaranteed 4-alignment, so accessing at u32 is okay.
@@ -112,38 +104,32 @@ intrinsics! {
112104
__aeabi_memcpy(dest as *mut u8, src as *const u8, n);
113105
}
114106

115-
#[weak]
116107
#[cfg(not(target_os = "ios"))]
117108
pub unsafe extern "aapcs" fn __aeabi_memcpy8(dest: *mut u8, src: *const u8, n: usize) {
118109
__aeabi_memcpy4(dest, src, n);
119110
}
120111

121-
#[weak]
122112
#[cfg(not(target_os = "ios"))]
123113
pub unsafe extern "aapcs" fn __aeabi_memmove(dest: *mut u8, src: *const u8, n: usize) {
124114
crate::mem::memmove(dest, src, n);
125115
}
126116

127-
#[weak]
128117
#[cfg(not(any(target_os = "ios", target_env = "msvc")))]
129118
pub unsafe extern "aapcs" fn __aeabi_memmove4(dest: *mut u8, src: *const u8, n: usize) {
130119
__aeabi_memmove(dest, src, n);
131120
}
132121

133-
#[weak]
134122
#[cfg(not(any(target_os = "ios", target_env = "msvc")))]
135123
pub unsafe extern "aapcs" fn __aeabi_memmove8(dest: *mut u8, src: *const u8, n: usize) {
136124
__aeabi_memmove(dest, src, n);
137125
}
138126

139-
#[weak]
140127
#[cfg(not(target_os = "ios"))]
141128
pub unsafe extern "aapcs" fn __aeabi_memset(dest: *mut u8, n: usize, c: i32) {
142129
// Note the different argument order
143130
crate::mem::memset(dest, c, n);
144131
}
145132

146-
#[weak]
147133
#[cfg(not(target_os = "ios"))]
148134
pub unsafe extern "aapcs" fn __aeabi_memset4(dest: *mut u8, n: usize, c: i32) {
149135
let mut dest = dest as *mut u32;
@@ -161,25 +147,21 @@ intrinsics! {
161147
__aeabi_memset(dest as *mut u8, n, byte as i32);
162148
}
163149

164-
#[weak]
165150
#[cfg(not(target_os = "ios"))]
166151
pub unsafe extern "aapcs" fn __aeabi_memset8(dest: *mut u8, n: usize, c: i32) {
167152
__aeabi_memset4(dest, n, c);
168153
}
169154

170-
#[weak]
171155
#[cfg(not(target_os = "ios"))]
172156
pub unsafe extern "aapcs" fn __aeabi_memclr(dest: *mut u8, n: usize) {
173157
__aeabi_memset(dest, n, 0);
174158
}
175159

176-
#[weak]
177160
#[cfg(not(any(target_os = "ios", target_env = "msvc")))]
178161
pub unsafe extern "aapcs" fn __aeabi_memclr4(dest: *mut u8, n: usize) {
179162
__aeabi_memset4(dest, n, 0);
180163
}
181164

182-
#[weak]
183165
#[cfg(not(any(target_os = "ios", target_env = "msvc")))]
184166
pub unsafe extern "aapcs" fn __aeabi_memclr8(dest: *mut u8, n: usize) {
185167
__aeabi_memset4(dest, n, 0);

‎src/macros.rs

+38-101
Original file line numberDiff line numberDiff line change
@@ -25,11 +25,12 @@ macro_rules! public_test_dep {
2525
/// platforms need and elsewhere in this library it just looks like normal Rust
2626
/// code.
2727
///
28-
/// When the weak-intrinsics feature is enabled, all intrinsics functions are
29-
/// marked with #[linkage = "weak"] so that they can be replaced by another
30-
/// implementation at link time. This is particularly useful for mixed Rust/C++
31-
/// binaries that want to use the C++ intrinsics, otherwise linking against the
32-
/// Rust stdlib will replace those from the compiler-rt library.
28+
/// All intrinsics functions are marked with #[linkage = "weak"] when
29+
/// `not(windows) and not(target_vendor = "apple")`.
30+
/// `weak` linkage attribute is used so that these functions can be replaced
31+
/// by another implementation at link time. This is particularly useful for mixed
32+
/// Rust/C++ binaries that want to use the C++ intrinsics, otherwise linking against
33+
/// the Rust stdlib will replace those from the compiler-rt library.
3334
///
3435
/// This macro is structured to be invoked with a bunch of functions that looks
3536
/// like:
@@ -53,10 +54,6 @@ macro_rules! public_test_dep {
5354
///
5455
/// A quick overview of attributes supported right now are:
5556
///
56-
/// * `weak` - indicates that the function should always be given weak linkage.
57-
/// This attribute must come before other attributes, as the other attributes
58-
/// will generate the final output function and need to have `weak` modify
59-
/// them.
6057
/// * `maybe_use_optimized_c_shim` - indicates that the Rust implementation is
6158
/// ignored if an optimized C version was compiled.
6259
/// * `aapcs_on_arm` - forces the ABI of the function to be `"aapcs"` on ARM and
@@ -128,67 +125,6 @@ macro_rules! intrinsics {
128125
intrinsics!($($rest)*);
129126
);
130127

131-
// Explicit weak linkage gets dropped when weak-intrinsics is on since it
132-
// will be added unconditionally to all intrinsics and would conflict
133-
// otherwise.
134-
(
135-
#[weak]
136-
$(#[$($attr:tt)*])*
137-
pub extern $abi:tt fn $name:ident( $($argname:ident: $ty:ty),* ) $(-> $ret:ty)? {
138-
$($body:tt)*
139-
}
140-
141-
$($rest:tt)*
142-
) => (
143-
#[cfg(feature = "weak-intrinsics")]
144-
intrinsics! {
145-
$(#[$($attr)*])*
146-
pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
147-
$($body)*
148-
}
149-
}
150-
151-
#[cfg(not(feature = "weak-intrinsics"))]
152-
intrinsics! {
153-
$(#[$($attr)*])*
154-
#[linkage = "weak"]
155-
pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
156-
$($body)*
157-
}
158-
}
159-
160-
intrinsics!($($rest)*);
161-
);
162-
// Same as above but for unsafe.
163-
(
164-
#[weak]
165-
$(#[$($attr:tt)*])*
166-
pub unsafe extern $abi:tt fn $name:ident( $($argname:ident: $ty:ty),* ) $(-> $ret:ty)? {
167-
$($body:tt)*
168-
}
169-
170-
$($rest:tt)*
171-
) => (
172-
#[cfg(feature = "weak-intrinsics")]
173-
intrinsics! {
174-
$(#[$($attr)*])*
175-
pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
176-
$($body)*
177-
}
178-
}
179-
180-
#[cfg(not(feature = "weak-intrinsics"))]
181-
intrinsics! {
182-
$(#[$($attr)*])*
183-
#[linkage = "weak"]
184-
pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
185-
$($body)*
186-
}
187-
}
188-
189-
intrinsics!($($rest)*);
190-
);
191-
192128
// Right now there's a bunch of architecture-optimized intrinsics in the
193129
// stock compiler-rt implementation. Not all of these have been ported over
194130
// to Rust yet so when the `c` feature of this crate is enabled we fall back
@@ -211,7 +147,6 @@ macro_rules! intrinsics {
211147
$($rest:tt)*
212148
) => (
213149
#[cfg($name = "optimized-c")]
214-
#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
215150
pub $(unsafe $($empty)? )? extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
216151
extern $abi {
217152
fn $name($($argname: $ty),*) $(-> $ret)?;
@@ -311,16 +246,15 @@ macro_rules! intrinsics {
311246
) => (
312247
#[cfg(all(any(windows, target_os = "uefi"), target_arch = "x86_64"))]
313248
$(#[$($attr)*])*
314-
#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
315249
pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
316250
$($body)*
317251
}
318252

319-
#[cfg(all(any(windows, target_os = "uefi"), target_arch = "x86_64"))]
320-
pub mod $name {
321-
#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
322-
#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
323-
pub extern $abi fn $name( $($argname: $ty),* )
253+
#[cfg(all(any(windows, target_os = "uefi"), target_arch = "x86_64", not(feature = "mangled-names")))]
254+
mod $name {
255+
#[no_mangle]
256+
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), linkage = "weak")]
257+
extern $abi fn $name( $($argname: $ty),* )
324258
-> $crate::macros::win64_128bit_abi_hack::U64x2
325259
{
326260
let e: $($ret)? = super::$name($($argname),*);
@@ -357,20 +291,20 @@ macro_rules! intrinsics {
357291
$($body)*
358292
}
359293

360-
#[cfg(target_arch = "arm")]
361-
pub mod $name {
362-
#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
363-
#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
364-
pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
294+
#[cfg(all(target_arch = "arm", not(feature = "mangled-names")))]
295+
mod $name {
296+
#[no_mangle]
297+
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), linkage = "weak")]
298+
extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
365299
super::$name($($argname),*)
366300
}
367301
}
368302

369-
#[cfg(target_arch = "arm")]
370-
pub mod $alias {
371-
#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
372-
#[cfg_attr(any(all(not(windows), not(target_vendor="apple")), feature = "weak-intrinsics"), linkage = "weak")]
373-
pub extern "aapcs" fn $alias( $($argname: $ty),* ) $(-> $ret)? {
303+
#[cfg(all(target_arch = "arm", not(feature = "mangled-names")))]
304+
mod $alias {
305+
#[no_mangle]
306+
#[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
307+
extern "aapcs" fn $alias( $($argname: $ty),* ) $(-> $ret)? {
374308
super::$name($($argname),*)
375309
}
376310
}
@@ -401,12 +335,12 @@ macro_rules! intrinsics {
401335
$($body)*
402336
}
403337

404-
#[cfg(feature = "mem")]
405-
pub mod $name {
338+
#[cfg(all(feature = "mem", not(feature = "mangled-names")))]
339+
mod $name {
406340
$(#[$($attr)*])*
407-
#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
408-
#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
409-
pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
341+
#[no_mangle]
342+
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), linkage = "weak")]
343+
unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
410344
super::$name($($argname),*)
411345
}
412346
}
@@ -425,11 +359,12 @@ macro_rules! intrinsics {
425359

426360
$($rest:tt)*
427361
) => (
362+
// `#[naked]` definitions are referenced by other places, so we can't use `cfg` like the others
428363
pub mod $name {
429364
#[naked]
430365
$(#[$($attr)*])*
431366
#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
432-
#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
367+
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), linkage = "weak")]
433368
pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
434369
$($body)*
435370
}
@@ -492,11 +427,12 @@ macro_rules! intrinsics {
492427
$($body)*
493428
}
494429

495-
pub mod $name {
430+
#[cfg(not(feature = "mangled-names"))]
431+
mod $name {
496432
$(#[$($attr)*])*
497-
#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
498-
#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
499-
pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
433+
#[no_mangle]
434+
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), linkage = "weak")]
435+
extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
500436
super::$name($($argname),*)
501437
}
502438
}
@@ -518,11 +454,12 @@ macro_rules! intrinsics {
518454
$($body)*
519455
}
520456

521-
pub mod $name {
457+
#[cfg(not(feature = "mangled-names"))]
458+
mod $name {
522459
$(#[$($attr)*])*
523-
#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
524-
#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
525-
pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
460+
#[no_mangle]
461+
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), linkage = "weak")]
462+
unsafe fn $name( $($argname: $ty),* ) $(-> $ret)? {
526463
super::$name($($argname),*)
527464
}
528465
}

‎src/math.rs

-3
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,6 @@ macro_rules! no_mangle {
99
($(fn $fun:ident($($iid:ident : $ity:ty),+) -> $oty:ty;)+) => {
1010
intrinsics! {
1111
$(
12-
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), weak)]
1312
pub extern "C" fn $fun($($iid: $ity),+) -> $oty {
1413
self::libm::$fun($($iid),+)
1514
}
@@ -94,14 +93,12 @@ no_mangle! {
9493
}
9594

9695
intrinsics! {
97-
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), weak)]
9896
pub extern "C" fn lgamma_r(x: f64, s: &mut i32) -> f64 {
9997
let r = self::libm::lgamma_r(x);
10098
*s = r.1;
10199
r.0
102100
}
103101

104-
#[cfg_attr(all(not(windows), not(target_vendor = "apple")), weak)]
105102
pub extern "C" fn lgammaf_r(x: f32, s: &mut i32) -> f32 {
106103
let r = self::libm::lgammaf_r(x);
107104
*s = r.1;

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