Auto merge of #28605 - alexcrichton:link-native-first, r=brson

This commit swaps the order of linking local native libraries and upstream
native libraries on the linker command line. Detail of bugs this can cause can
be found in #28595, and this change also invalidates the test case that was
added for #12446 which is now considered a bug because the downstream dependency
would need to declare that it depends on the native library somehow.

Closes #28595
[breaking-change]

1 files changed, 12 insertions, 7 deletions

diff --git a/src/liballoc_jemalloc/lib.rs b/src/liballoc_jemalloc/lib.rs
index 4179cbe8a7b..80a831fd207 100644
--- a/src/liballoc_jemalloc/lib.rs
+++ b/src/liballoc_jemalloc/lib.rs
@@ -27,7 +27,19 @@ extern crate libc;
 
 use libc::{c_int, c_void, size_t};
 
+// Linkage directives to pull in jemalloc and its dependencies.
+//
+// On some platforms we need to be sure to link in `pthread` which jemalloc
+// depends on, and specifically on android we need to also link to libgcc.
+// Currently jemalloc is compiled with gcc which will generate calls to
+// intrinsics that are libgcc specific (e.g. those intrinsics aren't present in
+// libcompiler-rt), so link that in to get that support.
 #[link(name = "jemalloc", kind = "static")]
+#[cfg_attr(target_os = "android", link(name = "gcc"))]
+#[cfg_attr(all(not(windows),
+               not(target_os = "android"),
+               not(target_env = "musl")),
+           link(name = "pthread"))]
 extern {
     fn je_mallocx(size: size_t, flags: c_int) -> *mut c_void;
     fn je_rallocx(ptr: *mut c_void, size: size_t, flags: c_int) -> *mut c_void;
@@ -37,13 +49,6 @@ extern {
     fn je_nallocx(size: size_t, flags: c_int) -> size_t;
 }
 
-// -lpthread needs to occur after -ljemalloc, the earlier argument isn't enough
-#[cfg(all(not(windows),
-          not(target_os = "android"),
-          not(target_env = "musl")))]
-#[link(name = "pthread")]
-extern {}
-
 // The minimum alignment guaranteed by the architecture. This value is used to
 // add fast paths for low alignment values. In practice, the alignment is a
 // constant at the call site and the branch will be optimized out.