Merge pull request #526 from danakj/weak
This commit is contained in:
Amanieu d'Antras
GitHub
commit
8f15d964aa
4 changed files with 141 additions and 24 deletions
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@ -65,6 +65,17 @@ rustc-dep-of-std = ['compiler-builtins', 'core']
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# are not normally public but are required by the `testcrate`
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public-test-deps = []
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# Marks all intrinsics functions with weak linkage so that they can be
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# replaced at link time by another implementation. This is particularly useful
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# for mixed Rust/C++ binaries that want to use the C++ intrinsics, otherwise
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# linking against the Rust stdlib will replace those from the compiler-rt
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# library.
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#
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# Unlike the "c" feature, the intrinsics are still provided by the Rust
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# implementations and each will be used unless a stronger symbol replaces
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# it during linking.
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weak-intrinsics = []
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[[example]]
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name = "intrinsics"
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required-features = ["compiler-builtins"]
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@ -20,9 +20,9 @@ macro_rules! bl {
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intrinsics! {
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// NOTE This function and the ones below are implemented using assembly because they are using a
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// custom calling convention which can't be implemented using a normal Rust function.
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
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#[naked]
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#[cfg(not(target_env = "msvc"))]
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
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pub unsafe extern "C" fn __aeabi_uidivmod() {
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core::arch::asm!(
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"push {{lr}}",
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@ -36,8 +36,8 @@ intrinsics! {
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);
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}
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
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#[naked]
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
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pub unsafe extern "C" fn __aeabi_uldivmod() {
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core::arch::asm!(
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"push {{r4, lr}}",
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@ -53,8 +53,8 @@ intrinsics! {
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);
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}
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
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#[naked]
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
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pub unsafe extern "C" fn __aeabi_idivmod() {
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core::arch::asm!(
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"push {{r0, r1, r4, lr}}",
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@ -67,8 +67,8 @@ intrinsics! {
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);
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}
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
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#[naked]
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
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pub unsafe extern "C" fn __aeabi_ldivmod() {
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core::arch::asm!(
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"push {{r4, lr}}",
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@ -88,14 +88,14 @@ intrinsics! {
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// with custom implementation.
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// FIXME: The `*4` and `*8` variants should be defined as aliases.
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#[weak]
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#[cfg(not(target_os = "ios"))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memcpy(dest: *mut u8, src: *const u8, n: usize) {
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::mem::memcpy(dest, src, n);
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}
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#[weak]
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#[cfg(not(target_os = "ios"))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memcpy4(dest: *mut u8, src: *const u8, n: usize) {
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// We are guaranteed 4-alignment, so accessing at u32 is okay.
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let mut dest = dest as *mut u32;
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@ -112,39 +112,39 @@ intrinsics! {
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__aeabi_memcpy(dest as *mut u8, src as *const u8, n);
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}
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#[weak]
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#[cfg(not(target_os = "ios"))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memcpy8(dest: *mut u8, src: *const u8, n: usize) {
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__aeabi_memcpy4(dest, src, n);
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}
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#[weak]
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#[cfg(not(target_os = "ios"))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memmove(dest: *mut u8, src: *const u8, n: usize) {
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::mem::memmove(dest, src, n);
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}
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#[weak]
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#[cfg(not(any(target_os = "ios", target_env = "msvc")))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memmove4(dest: *mut u8, src: *const u8, n: usize) {
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__aeabi_memmove(dest, src, n);
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}
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#[weak]
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#[cfg(not(any(target_os = "ios", target_env = "msvc")))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memmove8(dest: *mut u8, src: *const u8, n: usize) {
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__aeabi_memmove(dest, src, n);
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}
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#[weak]
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#[cfg(not(target_os = "ios"))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memset(dest: *mut u8, n: usize, c: i32) {
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// Note the different argument order
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::mem::memset(dest, c, n);
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}
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#[weak]
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#[cfg(not(target_os = "ios"))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memset4(dest: *mut u8, n: usize, c: i32) {
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let mut dest = dest as *mut u32;
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let mut n = n;
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@ -161,26 +161,26 @@ intrinsics! {
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__aeabi_memset(dest as *mut u8, n, byte as i32);
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}
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#[weak]
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#[cfg(not(target_os = "ios"))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memset8(dest: *mut u8, n: usize, c: i32) {
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__aeabi_memset4(dest, n, c);
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}
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#[weak]
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#[cfg(not(target_os = "ios"))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memclr(dest: *mut u8, n: usize) {
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__aeabi_memset(dest, n, 0);
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}
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#[weak]
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#[cfg(not(any(target_os = "ios", target_env = "msvc")))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memclr4(dest: *mut u8, n: usize) {
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__aeabi_memset4(dest, n, 0);
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}
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#[weak]
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#[cfg(not(any(target_os = "ios", target_env = "msvc")))]
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#[linkage = "weak"]
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pub unsafe extern "aapcs" fn __aeabi_memclr8(dest: *mut u8, n: usize) {
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__aeabi_memset4(dest, n, 0);
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}
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@ -25,6 +25,12 @@ macro_rules! public_test_dep {
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/// platforms need and elsewhere in this library it just looks like normal Rust
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/// code.
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///
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/// When the weak-intrinsics feature is enabled, all intrinsics functions are
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/// marked with #[linkage = "weak"] so that they can be replaced by another
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/// implementation at link time. This is particularly useful for mixed Rust/C++
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/// binaries that want to use the C++ intrinsics, otherwise linking against the
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/// Rust stdlib will replace those from the compiler-rt library.
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///
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/// This macro is structured to be invoked with a bunch of functions that looks
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/// like:
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///
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@ -46,6 +52,10 @@ macro_rules! public_test_dep {
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///
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/// A quick overview of attributes supported right now are:
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///
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/// * `weak` - indicates that the function should always be given weak linkage.
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/// This attribute must come before other attributes, as the other attributes
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/// will generate the final output function and need to have `weak` modify
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/// them.
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/// * `maybe_use_optimized_c_shim` - indicates that the Rust implementation is
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/// ignored if an optimized C version was compiled.
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/// * `aapcs_on_arm` - forces the ABI of the function to be `"aapcs"` on ARM and
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@ -57,7 +67,6 @@ macro_rules! public_test_dep {
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/// it's a normal ABI elsewhere for returning a 128 bit integer.
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/// * `arm_aeabi_alias` - handles the "aliasing" of various intrinsics on ARM
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/// their otherwise typical names to other prefixed ones.
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///
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macro_rules! intrinsics {
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() => ();
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@ -89,6 +98,95 @@ macro_rules! intrinsics {
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intrinsics!($($rest)*);
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);
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// Same as above but for unsafe.
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(
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#[cfg_attr($e:meta, $($attr:tt)*)]
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$(#[$($attrs:tt)*])*
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pub unsafe extern $abi:tt fn $name:ident( $($argname:ident: $ty:ty),* ) $(-> $ret:ty)? {
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$($body:tt)*
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}
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$($rest:tt)*
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) => (
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#[cfg($e)]
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intrinsics! {
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#[$($attr)*]
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$(#[$($attrs)*])*
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pub unsafe extern $abi fn $name($($argname: $ty),*) $(-> $ret)? {
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$($body)*
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}
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}
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#[cfg(not($e))]
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intrinsics! {
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$(#[$($attrs)*])*
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pub unsafe extern $abi fn $name($($argname: $ty),*) $(-> $ret)? {
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$($body)*
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}
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}
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intrinsics!($($rest)*);
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);
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// Explicit weak linkage gets dropped when weak-intrinsics is on since it
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// will be added unconditionally to all intrinsics and would conflict
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// otherwise.
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(
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#[weak]
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$(#[$($attr:tt)*])*
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pub extern $abi:tt fn $name:ident( $($argname:ident: $ty:ty),* ) $(-> $ret:ty)? {
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$($body:tt)*
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}
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$($rest:tt)*
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) => (
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#[cfg(feature = "weak-intrinsics")]
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intrinsics! {
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$(#[$($attr)*])*
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pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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$($body)*
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}
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}
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#[cfg(not(feature = "weak-intrinsics"))]
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intrinsics! {
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$(#[$($attr)*])*
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#[linkage = "weak"]
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pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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$($body)*
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}
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}
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intrinsics!($($rest)*);
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);
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// Same as above but for unsafe.
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(
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#[weak]
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$(#[$($attr:tt)*])*
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pub unsafe extern $abi:tt fn $name:ident( $($argname:ident: $ty:ty),* ) $(-> $ret:ty)? {
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$($body:tt)*
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}
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$($rest:tt)*
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) => (
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#[cfg(feature = "weak-intrinsics")]
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intrinsics! {
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$(#[$($attr)*])*
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pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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$($body)*
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}
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}
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#[cfg(not(feature = "weak-intrinsics"))]
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intrinsics! {
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$(#[$($attr)*])*
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#[linkage = "weak"]
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pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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$($body)*
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}
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}
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intrinsics!($($rest)*);
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);
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// Right now there's a bunch of architecture-optimized intrinsics in the
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// stock compiler-rt implementation. Not all of these have been ported over
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@ -112,6 +210,7 @@ macro_rules! intrinsics {
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$($rest:tt)*
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) => (
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#[cfg($name = "optimized-c")]
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#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
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pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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extern $abi {
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fn $name($($argname: $ty),*) $(-> $ret)?;
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@ -211,6 +310,7 @@ macro_rules! intrinsics {
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) => (
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#[cfg(all(any(windows, target_os = "uefi"), target_arch = "x86_64"))]
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$(#[$($attr)*])*
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#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
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pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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$($body)*
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}
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@ -218,6 +318,7 @@ macro_rules! intrinsics {
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#[cfg(all(any(windows, target_os = "uefi"), target_arch = "x86_64"))]
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pub mod $name {
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#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
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#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
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pub extern $abi fn $name( $($argname: $ty),* )
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-> ::macros::win64_128bit_abi_hack::U64x2
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{
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@ -258,6 +359,7 @@ macro_rules! intrinsics {
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#[cfg(target_arch = "arm")]
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pub mod $name {
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#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
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#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
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pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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super::$name($($argname),*)
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}
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@ -266,7 +368,7 @@ macro_rules! intrinsics {
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#[cfg(target_arch = "arm")]
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pub mod $alias {
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#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
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#[cfg_attr(all(not(windows), not(target_vendor="apple")), linkage = "weak")]
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#[cfg_attr(any(all(not(windows), not(target_vendor="apple"), feature = "weak-intrinsics")), linkage = "weak")]
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pub extern "aapcs" fn $alias( $($argname: $ty),* ) $(-> $ret)? {
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super::$name($($argname),*)
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}
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@ -302,6 +404,7 @@ macro_rules! intrinsics {
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pub mod $name {
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$(#[$($attr)*])*
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#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
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#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
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pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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super::$name($($argname),*)
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}
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@ -325,6 +428,7 @@ macro_rules! intrinsics {
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#[naked]
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$(#[$($attr)*])*
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#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
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#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
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pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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$($body)*
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}
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@ -391,6 +495,7 @@ macro_rules! intrinsics {
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pub mod $name {
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$(#[$($attr)*])*
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#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
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#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
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pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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super::$name($($argname),*)
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}
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@ -416,6 +521,7 @@ macro_rules! intrinsics {
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pub mod $name {
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$(#[$($attr)*])*
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#[cfg_attr(not(feature = "mangled-names"), no_mangle)]
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#[cfg_attr(feature = "weak-intrinsics", linkage = "weak")]
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pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
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super::$name($($argname),*)
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}
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|
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@ -20,15 +20,15 @@ use core::ops::{BitOr, Shl};
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mod impls;
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intrinsics! {
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), weak)]
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#[mem_builtin]
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), linkage = "weak")]
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pub unsafe extern "C" fn memcpy(dest: *mut u8, src: *const u8, n: usize) -> *mut u8 {
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impls::copy_forward(dest, src, n);
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dest
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}
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), weak)]
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#[mem_builtin]
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), linkage = "weak")]
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pub unsafe extern "C" fn memmove(dest: *mut u8, src: *const u8, n: usize) -> *mut u8 {
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let delta = (dest as usize).wrapping_sub(src as usize);
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if delta >= n {
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@ -41,27 +41,27 @@ intrinsics! {
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dest
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}
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), weak)]
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#[mem_builtin]
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), linkage = "weak")]
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pub unsafe extern "C" fn memset(s: *mut u8, c: crate::mem::c_int, n: usize) -> *mut u8 {
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impls::set_bytes(s, c as u8, n);
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s
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}
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), weak)]
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#[mem_builtin]
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), linkage = "weak")]
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pub unsafe extern "C" fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
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impls::compare_bytes(s1, s2, n)
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}
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), weak)]
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#[mem_builtin]
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#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), linkage = "weak")]
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pub unsafe extern "C" fn bcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
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memcmp(s1, s2, n)
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}
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|
||||
#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), weak)]
|
||||
#[mem_builtin]
|
||||
#[cfg_attr(not(all(target_os = "windows", target_env = "gnu")), linkage = "weak")]
|
||||
pub unsafe extern "C" fn strlen(s: *const core::ffi::c_char) -> usize {
|
||||
impls::c_string_length(s)
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue