From 18600043537d956c58e1d5a6f045eb160d6ef6e8 Mon Sep 17 00:00:00 2001
From: Nick Spinale <nick@nickspinale.com>
Date: Mon, 6 May 2024 13:53:05 -0400
Subject: [PATCH] Remove supplementary definitions of __bswapsi2

Build compiler-builtins with the "c" feature by default

Signed-off-by: Nick Spinale <nick@nickspinale.com>
---
 .../root-task/ring-test-harness/src/lib.rs    |  9 ------
 .../utils/src/compiler_builtins_supplement.rs | 12 --------
 .../network/rustls/utils/src/lib.rs           |  1 -
 hacking/nix/rust-utils/build-sysroot.nix      | 28 ++++++++++++++++---
 4 files changed, 24 insertions(+), 26 deletions(-)
 delete mode 100644 crates/sel4-async/network/rustls/utils/src/compiler_builtins_supplement.rs

diff --git a/crates/private/tests/root-task/ring-test-harness/src/lib.rs b/crates/private/tests/root-task/ring-test-harness/src/lib.rs
index 79d86123d..a41404141 100644
--- a/crates/private/tests/root-task/ring-test-harness/src/lib.rs
+++ b/crates/private/tests/root-task/ring-test-harness/src/lib.rs
@@ -51,12 +51,3 @@ mod dummy_custom_getrandom {
 
     getrandom::register_custom_getrandom!(dummy_custom_getrandom);
 }
-
-mod compiler_builtins_supplement {
-    // https://github.com/rust-lang/compiler-builtins/pull/563
-    #[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))]
-    #[no_mangle]
-    pub extern "C" fn __bswapsi2(u: u32) -> u32 {
-        u.swap_bytes()
-    }
-}
diff --git a/crates/sel4-async/network/rustls/utils/src/compiler_builtins_supplement.rs b/crates/sel4-async/network/rustls/utils/src/compiler_builtins_supplement.rs
deleted file mode 100644
index 61eef79d6..000000000
--- a/crates/sel4-async/network/rustls/utils/src/compiler_builtins_supplement.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-//
-// Copyright 2023, Colias Group, LLC
-//
-// SPDX-License-Identifier: BSD-2-Clause
-//
-
-// https://github.com/rust-lang/compiler-builtins/pull/563
-#[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))]
-#[no_mangle]
-pub extern "C" fn __bswapsi2(u: u32) -> u32 {
-    u.swap_bytes()
-}
diff --git a/crates/sel4-async/network/rustls/utils/src/lib.rs b/crates/sel4-async/network/rustls/utils/src/lib.rs
index 57836621c..16633f827 100644
--- a/crates/sel4-async/network/rustls/utils/src/lib.rs
+++ b/crates/sel4-async/network/rustls/utils/src/lib.rs
@@ -10,7 +10,6 @@
 
 extern crate alloc;
 
-mod compiler_builtins_supplement;
 mod dummy_custom_getrandom;
 mod no_server_cert_verifier;
 mod time_provider_impl;
diff --git a/hacking/nix/rust-utils/build-sysroot.nix b/hacking/nix/rust-utils/build-sysroot.nix
index c815329c9..ae8772c5a 100644
--- a/hacking/nix/rust-utils/build-sysroot.nix
+++ b/hacking/nix/rust-utils/build-sysroot.nix
@@ -5,7 +5,8 @@
 #
 
 { lib, stdenv, buildPlatform, hostPlatform, buildPackages
-, runCommand, linkFarm
+, runCommand, runCommandCC, linkFarm
+, fetchurl
 , vendorLockfile, crateUtils, symlinkToRegularFile
 , defaultRustToolchain, defaultRustTargetInfo
 , rustToolchain ? defaultRustToolchain
@@ -27,6 +28,7 @@ in
 , rustTargetInfo ? defaultRustTargetInfo
 , alloc ? true
 , compilerBuiltinsMem ? true
+, compilerBuiltinsC ? true
 }:
 
 let
@@ -80,15 +82,33 @@ let
 
   features = lib.concatStringsSep "," (lib.optionals compilerBuiltinsMem [
     "compiler-builtins-mem"
+  ] ++ lib.optionals compilerBuiltinsC [
+    "compiler-builtins-c"
   ]);
 
+  compilerRTSource = let
+    v = "18.0-2024-02-13";
+    name = "compiler-rt";
+    llvmSourceTarball = fetchurl {
+      name = "llvm-project.tar.gz";
+      url = "https://github.com/rust-lang/llvm-project/archive/rustc/${v}.tar.gz";
+      sha256 = "sha256-fMc84lCWfNy0Xiq1X7nrT53MQPlfRqGEb4qBAmqehAA=";
+    };
+  in
+    runCommand name {} ''
+      tar xzf ${llvmSourceTarball} --strip-components 1 llvm-project-rustc-${v}/${name}
+      mv ${name} $out
+    '';
+
 in
-runCommand "sysroot" {
+(if compilerBuiltinsC then runCommandCC else runCommand) "sysroot" ({
   depsBuildBuild = [ buildPackages.stdenv.cc ];
   nativeBuildInputs = [ rustToolchain ];
-
   RUST_TARGET_PATH = rustTargetInfo.path;
-} ''
+} // lib.optionalAttrs compilerBuiltinsC {
+  "CC_${rustTargetInfo.name}" = "${stdenv.cc.targetPrefix}gcc";
+  RUST_COMPILER_RT_ROOT = compilerRTSource;
+}) ''
   cargo build \
     -Z unstable-options \
     --offline \