Source: rustc
Version: 1.31.0+dfsg1-2
Severity: normal
Tags: upstream patch
User: debian-sparc@lists.debian.org
Usertags: sparc64
Hi!
The Rust compiler misses some special handling for empty structs in
the C ABI. This was discovered today by Michael Karcher who has
written a patch to address the issue, it's already sent upstream [1].
I'm attaching the patch. With the patches from #916818, #917000
and #917191, the testsuite failures on sparc64 drop to 9 for me.
> [1] https://github.com/rust-lang/rust/pull/57085
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaub...@debian.org
`. `' Freie Universitaet Berlin - glaub...@physik.fu-berlin.de
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
>From 970747edb47795a1012929ea468c2b75f087b289 Mon Sep 17 00:00:00 2001
From: Michael Karcher <git...@mkarcher.dialup.fu-berlin.de>
Date: Sun, 23 Dec 2018 20:33:52 +0100
Subject: [PATCH] librustc_codegen_llvm: Don't eliminate empty structs in C ABI
on linux-sparc64
This is in accordance with the SPARC Compliance Definition 4.2.1,
Page 3P-12. It says that structs of up to 8 bytes (which applies
to empty structs as well) are to be passed in one register.
---
src/librustc_codegen_llvm/abi.rs | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/src/librustc_codegen_llvm/abi.rs b/src/librustc_codegen_llvm/abi.rs
index b8954dee79..c083137f08 100644
--- a/src/librustc_codegen_llvm/abi.rs
+++ b/src/librustc_codegen_llvm/abi.rs
@@ -456,6 +456,9 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
let linux_s390x = target.target_os == "linux"
&& target.arch == "s390x"
&& target.target_env == "gnu";
+ let linux_sparc64 = target.target_os == "linux"
+ && target.arch == "sparc64"
+ && target.target_env == "gnu";
let rust_abi = match sig.abi {
RustIntrinsic | PlatformIntrinsic | Rust | RustCall => true,
_ => false
@@ -526,8 +529,9 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
if arg.layout.is_zst() {
// For some forsaken reason, x86_64-pc-windows-gnu
// doesn't ignore zero-sized struct arguments.
- // The same is true for s390x-unknown-linux-gnu.
- if is_return || rust_abi || (!win_x64_gnu && !linux_s390x) {
+ // The same is true for s390x-unknown-linux-gnu
+ // and sparc64-unknown-linux-gnu.
+ if is_return || rust_abi || (!win_x64_gnu && !linux_s390x &&
!linux_sparc64) {
arg.mode = PassMode::Ignore;
}
}
--
2.20.1
