From fa108d9a86827a28c7bfb8ff98033734b2a5fd33 Mon Sep 17 00:00:00 2001
From: Dan Gohman <dev@sunfishcode.online>
Date: Thu, 30 Sep 2021 06:11:29 -0700
Subject: [PATCH] Remove the rsix dependency in cranelift-native. (#3395)

Revert the part of 47490b4383bf48cbde8b1c33301a7f7d326ee7cc which
changed cranelift-native to use rsix. It's just one call, and this lets
Cranelift users that don't otherwise depend on rsix to avoid it.
---
 Cargo.lock                  | 2 +-
 cranelift/native/Cargo.toml | 2 +-
 cranelift/native/src/lib.rs | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a2e80da3ea..6823f1b335 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -696,7 +696,7 @@ name = "cranelift-native"
 version = "0.77.0"
 dependencies = [
  "cranelift-codegen",
- "rsix",
+ "libc",
  "target-lexicon",
 ]
 
diff --git a/cranelift/native/Cargo.toml b/cranelift/native/Cargo.toml
index 96fe91f665..493778a463 100644
--- a/cranelift/native/Cargo.toml
+++ b/cranelift/native/Cargo.toml
@@ -15,7 +15,7 @@ cranelift-codegen = { path = "../codegen", version = "0.77.0", default-features
 target-lexicon = "0.12"
 
 [target.'cfg(target_arch = "s390x")'.dependencies]
-rsix = "0.23.0"
+libc = "0.2.95"
 
 [features]
 default = ["std"]
diff --git a/cranelift/native/src/lib.rs b/cranelift/native/src/lib.rs
index b2364c6ad9..cac50dee4e 100644
--- a/cranelift/native/src/lib.rs
+++ b/cranelift/native/src/lib.rs
@@ -126,7 +126,7 @@ pub fn builder_with_options(
     }
 
     // There is no is_s390x_feature_detected macro yet, so for now
-    // we use linux_hwcap from the rsix crate directly.
+    // we use getauxval from the libc crate directly.
     #[cfg(all(target_arch = "s390x", target_os = "linux"))]
     {
         use cranelift_codegen::settings::Configurable;
@@ -135,8 +135,8 @@ pub fn builder_with_options(
             return Ok(isa_builder);
         }
 
-        let v = rsix::process::linux_hwcap().0;
-        const HWCAP_S390X_VXRS_EXT2: usize = 32768;
+        let v = unsafe { libc::getauxval(libc::AT_HWCAP) };
+        const HWCAP_S390X_VXRS_EXT2: libc::c_ulong = 32768;
         if (v & HWCAP_S390X_VXRS_EXT2) != 0 {
             isa_builder.enable("has_vxrs_ext2").unwrap();
             // There is no separate HWCAP bit for mie2, so assume