libcompiler_builtins.rlib for armv7-linux-androideabi includes multiple definitions of __sync_fetch_and_add_4 #449
Description
This may be related to #420 and #412, but this seems pretty straightforward. In investigating rust-lang/rust#93310 I determined it was a bug with compiler-builtins and root caused it to 186517b. By making a small change, I was able to compile a rust toolchain which did not have the duplicate symbols:
diff --git a/build.rs b/build.rs
index dc1cd1d..b51cfe7 100644
--- a/build.rs
+++ b/build.rs
@@ -83,7 +83,7 @@ fn main() {
// rustc target (arm-linux-androideabi).
if llvm_target[0] == "armv4t"
|| llvm_target[0] == "armv5te"
- || llvm_target.get(2) == Some(&"androideabi")
+ // || llvm_target.get(2) == Some(&"androideabi")
{
println!("cargo:rustc-cfg=kernel_user_helpers")
}
The change in 186517b seems intended to affect only arm-linux-androideabi by the comment, but it ended up affecting armv7-linux-androideabi. Anyway, it looks like after the change arm-linux-androideabi properly only has the symbols once, but armv7-linux-androideabi is defining them twice:
~/src/compiler-builtins$ nm ~/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/arm-linux-androideabi/lib/libcompiler_builtins-14ef5f7d25cebe09.rlib 2> /dev/null | grep __sync_fetch_and_add_4 | wc -l
1
~/src/compiler-builtins$ nm ~/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/armv7-linux-androideabi/lib/libcompiler_builtins-be29c8b80b9c00b1.rlib 2> /dev/null | grep __sync_fetch_and_add_4 | wc -l
2
I'm not sure exactly how x.py ends up compiling compiler_builtins, since I was unable to reproduce the duplicate symbol issue in this repo alone (I tried cargo build --target armv7-linux-androideabi). I think there must be additional features enabled that cause the duplication in the end.