[Pkg-rust-maintainers] Bug#891902: rustc: Please include patch to disable kernel helpers on armel

[John Paul Adrian Glaubitz]

Source: rustc
Version: 1.23.0+dfsg1-1
Severity: normal
Tags: patch
User: debian-arm at lists.debian.org
Usertags: armel

Hi!

While trying to bootstrap rustc for armel, I ran into an issue where
rustc's own kernel helpers for atomics for ARM were causing linker
issues due to the fact modern versions of gcc already include such
helper functions itself [1].

While I haven't come up with a suitable patch for upstream yet as I
need to do some research first on which targets rustc's own helpers
are still required and on which they are not, I have whipped up a
simple patch which should work-around the issue for us in Debian
and allow us to bootstrap rustc for armel.

Could you include it in the next upload, preferably 1.24?

Thanks,
Adrian

> [1] https://github.com/rust-lang/rust/issues/48625

--
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913
-------------- next part --------------
--- rustc-1.24.0+dfsg1/src/libcompiler_builtins/build.rs.orig	2018-02-12 16:56:07.000000000 -0200
+++ rustc-1.24.0+dfsg1/src/libcompiler_builtins/build.rs	2018-03-02 07:22:10.124164162 -0300
@@ -52,9 +52,9 @@
     }
 
     // Only emit the ARM Linux atomic emulation on pre-ARMv6 architectures.
-    if llvm_target[0] == "armv4t" || llvm_target[0] == "armv5te" {
-        println!("cargo:rustc-cfg=kernel_user_helpers")
-    }
+    // if llvm_target[0] == "armv4t" || llvm_target[0] == "armv5te" {
+    //     println!("cargo:rustc-cfg=kernel_user_helpers")
+    // }
 }
 
 #[cfg(feature = "gen-tests")]