[experiment] android testing

Cargo.toml

@@ -70,6 +70,17 @@ rustc-dep-of-std = ['compiler-builtins', 'core']
 # are not normally public but are required by the `testcrate`
 public-test-deps = []
 
+# Marks all intrinsics functions with weak linkage so that they can be
+# replaced at link time by another implementation. This is particularly useful
+# for mixed Rust/C++ binaries that want to use the C++ intrinsics, otherwise
+# linking against the Rust stdlib will replace those from the compiler-rt
+# library.
+#
+# Unlike the "c" feature, the intrinsics are still provided by the Rust
+# implementations and each will be used unless a stronger symbol replaces
+# it during linking.
+weak-intrinsics = []
+
 [[example]]
 name = "intrinsics"
 required-features = ["compiler-builtins"]

build.rs

@@ -378,7 +378,11 @@ mod c {
 
         // On iOS and 32-bit OSX these are all just empty intrinsics, no need to
         // include them.
-        if target_vendor != "apple" || target_arch != "x86" {
+        if target_os != "ios"
+            && target_os != "watchos"
+            && target_os != "tvos"
+            && (target_vendor != "apple" || target_arch != "x86")
+        {
             sources.extend(&[
                 ("__absvti2", "absvti2.c"),
                 ("__addvti3", "addvti3.c"),
@@ -428,7 +432,12 @@ mod c {
             }
         }
 
-        if target_arch == "arm" && target_vendor != "apple" && target_env != "msvc" {
+        if target_arch == "arm"
+            && target_os != "ios"
+            && target_os != "watchos"
+            && target_os != "tvos"
+            && target_env != "msvc"
+        {
             sources.extend(&[
                 ("__aeabi_div0", "arm/aeabi_div0.c"),
                 ("__aeabi_drsub", "arm/aeabi_drsub.c"),

src/arm.rs

@@ -3,14 +3,14 @@
 
 use core::intrinsics;
 
-// Apple symbols have a leading underscore.
-#[cfg(target_vendor = "apple")]
+// iOS symbols have a leading underscore.
+#[cfg(target_os = "ios")]
 macro_rules! bl {
     ($func:literal) => {
         concat!("bl _", $func)
     };
 }
-#[cfg(not(target_vendor = "apple"))]
+#[cfg(not(target_os = "ios"))]
 macro_rules! bl {
     ($func:literal) => {
         concat!("bl ", $func)
@@ -20,6 +20,7 @@ macro_rules! bl {
 intrinsics! {
     // NOTE This function and the ones below are implemented using assembly because they are using a
     // custom calling convention which can't be implemented using a normal Rust function.
+    #[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
     #[naked]
     #[cfg(not(target_env = "msvc"))]
     pub unsafe extern "C" fn __aeabi_uidivmod() {
@@ -35,6 +36,7 @@ intrinsics! {
         );
     }
 
+    #[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
     #[naked]
     pub unsafe extern "C" fn __aeabi_uldivmod() {
         core::arch::asm!(
@@ -51,6 +53,7 @@ intrinsics! {
         );
     }
 
+    #[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
     #[naked]
     pub unsafe extern "C" fn __aeabi_idivmod() {
         core::arch::asm!(
@@ -64,6 +67,7 @@ intrinsics! {
         );
     }
 
+    #[cfg_attr(all(not(windows), not(target_vendor="apple")), weak)]
     #[naked]
     pub unsafe extern "C" fn __aeabi_ldivmod() {
         core::arch::asm!(
@@ -80,14 +84,18 @@ intrinsics! {
         );
     }
 
+    // The following functions use weak linkage to allow users to override
+    // with custom implementation.
     // FIXME: The `*4` and `*8` variants should be defined as aliases.
 
-    #[cfg(not(target_vendor = "apple"))]
+    #[weak]
+    #[cfg(not(target_os = "ios"))]
     pub unsafe extern "aapcs" fn __aeabi_memcpy(dest: *mut u8, src: *const u8, n: usize) {
         crate::mem::memcpy(dest, src, n);
     }
 
-    #[cfg(not(target_vendor = "apple"))]
+    #[weak]
+    #[cfg(not(target_os = "ios"))]
     pub unsafe extern "aapcs" fn __aeabi_memcpy4(dest: *mut u8, src: *const u8, n: usize) {
         // We are guaranteed 4-alignment, so accessing at u32 is okay.
         let mut dest = dest as *mut u32;
@@ -104,33 +112,39 @@ intrinsics! {
         __aeabi_memcpy(dest as *mut u8, src as *const u8, n);
     }
 
-    #[cfg(not(target_vendor = "apple"))]
+    #[weak]
+    #[cfg(not(target_os = "ios"))]
     pub unsafe extern "aapcs" fn __aeabi_memcpy8(dest: *mut u8, src: *const u8, n: usize) {
         __aeabi_memcpy4(dest, src, n);
     }
 
-    #[cfg(not(target_vendor = "apple"))]
+    #[weak]
+    #[cfg(not(target_os = "ios"))]
     pub unsafe extern "aapcs" fn __aeabi_memmove(dest: *mut u8, src: *const u8, n: usize) {
         crate::mem::memmove(dest, src, n);
     }
 
-    #[cfg(not(any(target_vendor = "apple", target_env = "msvc")))]
+    #[weak]
+    #[cfg(not(any(target_os = "ios", target_env = "msvc")))]
     pub unsafe extern "aapcs" fn __aeabi_memmove4(dest: *mut u8, src: *const u8, n: usize) {
         __aeabi_memmove(dest, src, n);
     }
 
-    #[cfg(not(any(target_vendor = "apple", target_env = "msvc")))]
+    #[weak]
+    #[cfg(not(any(target_os = "ios", target_env = "msvc")))]
     pub unsafe extern "aapcs" fn __aeabi_memmove8(dest: *mut u8, src: *const u8, n: usize) {
         __aeabi_memmove(dest, src, n);
     }
 
-    #[cfg(not(target_vendor = "apple"))]
+    #[weak]
+    #[cfg(not(target_os = "ios"))]
     pub unsafe extern "aapcs" fn __aeabi_memset(dest: *mut u8, n: usize, c: i32) {
         // Note the different argument order
         crate::mem::memset(dest, c, n);
     }
 
-    #[cfg(not(target_vendor = "apple"))]
+    #[weak]
+    #[cfg(not(target_os = "ios"))]
     pub unsafe extern "aapcs" fn __aeabi_memset4(dest: *mut u8, n: usize, c: i32) {
         let mut dest = dest as *mut u32;
         let mut n = n;
@@ -147,22 +161,26 @@ intrinsics! {
         __aeabi_memset(dest as *mut u8, n, byte as i32);
     }
 
-    #[cfg(not(target_vendor = "apple"))]
+    #[weak]
+    #[cfg(not(target_os = "ios"))]
     pub unsafe extern "aapcs" fn __aeabi_memset8(dest: *mut u8, n: usize, c: i32) {
         __aeabi_memset4(dest, n, c);
     }
 
-    #[cfg(not(target_vendor = "apple"))]
+    #[weak]
+    #[cfg(not(target_os = "ios"))]
     pub unsafe extern "aapcs" fn __aeabi_memclr(dest: *mut u8, n: usize) {
         __aeabi_memset(dest, n, 0);
     }
 
-    #[cfg(not(any(target_vendor = "apple", target_env = "msvc")))]
+    #[weak]
+    #[cfg(not(any(target_os = "ios", target_env = "msvc")))]
     pub unsafe extern "aapcs" fn __aeabi_memclr4(dest: *mut u8, n: usize) {
         __aeabi_memset4(dest, n, 0);
     }
 
-    #[cfg(not(any(target_vendor = "apple", target_env = "msvc")))]
+    #[weak]
+    #[cfg(not(any(target_os = "ios", target_env = "msvc")))]
     pub unsafe extern "aapcs" fn __aeabi_memclr8(dest: *mut u8, n: usize) {
         __aeabi_memset4(dest, n, 0);
     }