Build gnullvm toolchains on Windows natively

src/bootstrap/src/core/build_steps/dist.rs

@@ -338,7 +338,7 @@ fn runtime_dll_dist(rust_root: &Path, target: TargetSelection, builder: &Builder
         return;
     }
 
-    let (bin_path, libs_path) = get_cc_search_dirs(target, builder);
+    let (bin_path, _) = get_cc_search_dirs(target, builder);
 
     let mut rustc_dlls = vec![];
     // windows-gnu and windows-gnullvm require different runtime libs
@@ -354,15 +354,6 @@ fn runtime_dll_dist(rust_root: &Path, target: TargetSelection, builder: &Builder
     } else {
         panic!("Vendoring of runtime DLLs for `{target}` is not supported`");
     }
-    // FIXME(#144656): Remove this whole `let ...`
-    let bin_path = if target.ends_with("windows-gnullvm") && builder.host_target != target {
-        bin_path
-            .into_iter()
-            .chain(libs_path.iter().map(|path| path.with_file_name("bin")))
-            .collect()
-    } else {
-        bin_path
-    };
     let rustc_dlls = find_files(&rustc_dlls, &bin_path);
 
     // Copy runtime dlls next to rustc.exe
@@ -1721,7 +1712,7 @@ impl Step for Extended {
         tarballs.push(builder.ensure(Rustc { target_compiler }));
         tarballs.push(builder.ensure(Std { build_compiler, target }).expect("missing std"));
 
-        if target.is_windows_gnu() {
+        if target.is_windows_gnu() || target.is_windows_gnullvm() {
             tarballs.push(builder.ensure(Mingw { target }).expect("missing mingw"));
         }
 
@@ -1868,8 +1859,7 @@ impl Step for Extended {
             cmd.run(builder);
         }
 
-        // FIXME(mati865): `gnullvm` here is temporary, remove it once it can host itself
-        if target.is_windows() && !target.contains("gnullvm") {
+        if target.is_windows() {
             let exe = tmp.join("exe");
             let _ = fs::remove_dir_all(&exe);
 
@@ -1907,7 +1897,7 @@ impl Step for Extended {
                     prepare(tool);
                 }
             }
-            if target.is_windows_gnu() {
+            if target.is_windows_gnu() || target.is_windows_gnullvm() {
                 prepare("rust-mingw");
             }
 
@@ -2072,7 +2062,7 @@ impl Step for Extended {
                 .arg("-t")
                 .arg(etc.join("msi/remove-duplicates.xsl"))
                 .run(builder);
-            if target.is_windows_gnu() {
+            if target.is_windows_gnu() || target.is_windows_gnullvm() {
                 command(&heat)
                     .current_dir(&exe)
                     .arg("dir")
@@ -2121,7 +2111,7 @@ impl Step for Extended {
                 if built_tools.contains("miri") {
                     cmd.arg("-dMiriDir=miri");
                 }
-                if target.is_windows_gnu() {
+                if target.is_windows_gnu() || target.is_windows_gnullvm() {
                     cmd.arg("-dGccDir=rust-mingw");
                 }
                 cmd.run(builder);
@@ -2149,7 +2139,7 @@ impl Step for Extended {
             }
             candle("AnalysisGroup.wxs".as_ref());
 
-            if target.is_windows_gnu() {
+            if target.is_windows_gnu() || target.is_windows_gnullvm() {
                 candle("GccGroup.wxs".as_ref());
             }
 
@@ -2192,7 +2182,7 @@ impl Step for Extended {
                 cmd.arg("DocsGroup.wixobj");
             }
 
-            if target.is_windows_gnu() {
+            if target.is_windows_gnu() || target.is_windows_gnullvm() {
                 cmd.arg("GccGroup.wixobj");
             }
             // ICE57 wrongly complains about the shortcuts
@@ -2231,7 +2221,7 @@ fn add_env(
         .env("CFG_BUILD", target.triple)
         .env("CFG_CHANNEL", &builder.config.channel);
 
-    if target.contains("windows-gnullvm") {
+    if target.is_windows_gnullvm() {
         cmd.env("CFG_MINGW", "1").env("CFG_ABI", "LLVM");
     } else if target.is_windows_gnu() {
         cmd.env("CFG_MINGW", "1").env("CFG_ABI", "GNU");

src/ci/github-actions/jobs.yml

@@ -247,12 +247,6 @@ auto:
   - name: dist-s390x-linux
     <<: *job-linux-4c
 
-  - name: dist-aarch64-windows-gnullvm
-    <<: *job-linux-4c
-
-  - name: dist-x86_64-windows-gnullvm
-    <<: *job-linux-4c
-
   - name: dist-various-1
     <<: *job-linux-4c
 
@@ -689,6 +683,28 @@ auto:
       CODEGEN_BACKENDS: llvm,cranelift
     <<: *job-windows
 
+  - name: dist-aarch64-llvm-mingw
+    env:
+      SCRIPT: python x.py dist bootstrap --include-default-paths
+      RUST_CONFIGURE_ARGS: >-
+        --build=aarch64-pc-windows-gnullvm
+        --enable-full-tools
+        --enable-profiler
+      DIST_REQUIRE_ALL_TOOLS: 1
+      CODEGEN_BACKENDS: llvm,cranelift
+    <<: *job-windows-aarch64
+
+  - name: dist-x86_64-llvm-mingw
+    env:
+      SCRIPT: python x.py dist bootstrap --include-default-paths
+      RUST_CONFIGURE_ARGS: >-
+        --build=x86_64-pc-windows-gnullvm
+        --enable-full-tools
+        --enable-profiler
+      DIST_REQUIRE_ALL_TOOLS: 1
+      CODEGEN_BACKENDS: llvm,cranelift
+    <<: *job-windows
+
   - name: dist-x86_64-msvc-alt
     env:
       RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-extended --enable-profiler

src/ci/scripts/install-mingw.sh

@@ -8,22 +8,37 @@ source "$(cd "$(dirname "$0")" && pwd)/../shared.sh"
 
 MINGW_ARCHIVE_32="i686-14.1.0-release-posix-dwarf-msvcrt-rt_v12-rev0.7z"
 MINGW_ARCHIVE_64="x86_64-14.1.0-release-posix-seh-msvcrt-rt_v12-rev0.7z"
+LLVM_MINGW_ARCHIVE_AARCH64="llvm-mingw-20251104-ucrt-aarch64.zip"
+LLVM_MINGW_ARCHIVE_X86_64="llvm-mingw-20251104-ucrt-x86_64.zip"
 
 if isWindows && isKnownToBeMingwBuild; then
     case "${CI_JOB_NAME}" in
+        *aarch64-llvm*)
+            mingw_dir="clangarm64"
+            mingw_archive="${LLVM_MINGW_ARCHIVE_AARCH64}"
+            arch="aarch64"
+            # Rustup defaults to AArch64 MSVC which has a hard time building Ring crate
+            # for citool. MSVC jobs install special Clang build to solve that, but here
+            # it would be an overkill. So we just use toolchain that doesn't have this
+            # issue.
+            rustup default stable-aarch64-pc-windows-gnullvm
+            ;;
+        *x86_64-llvm*)
+            mingw_dir="clang64"
+            mingw_archive="${LLVM_MINGW_ARCHIVE_X86_64}"
+            arch="x86_64"
+            ;;
         *i686*)
-            bits=32
+            mingw_dir="mingw32"
             mingw_archive="${MINGW_ARCHIVE_32}"
             ;;
         *x86_64*)
-            bits=64
+            mingw_dir="mingw64"
             mingw_archive="${MINGW_ARCHIVE_64}"
             ;;
         *aarch64*)
-            # aarch64 is a cross-compiled target. Use the x86_64
-            # mingw, since that's the host architecture.
-            bits=64
-            mingw_archive="${MINGW_ARCHIVE_64}"
+            echo "AArch64 Windows is not supported by GNU tools"
+            exit 1
             ;;
         *)
             echo "src/ci/scripts/install-mingw.sh can't detect the builder's architecture"
@@ -38,14 +53,32 @@ if isWindows && isKnownToBeMingwBuild; then
     msys2Path="c:/msys64"
     ciCommandAddPath "${msys2Path}/usr/bin"
 
-    mingw_dir="mingw${bits}"
+    case "${mingw_archive}" in
+        *.7z)
+            curl -o mingw.7z "${MIRRORS_BASE}/${mingw_archive}"
+            7z x -y mingw.7z > /dev/null
+            ;;
+        *.zip)
+            curl -o mingw.zip "${MIRRORS_BASE}/${mingw_archive}"
+            unzip -q mingw.zip
+            mv llvm-mingw-20251104-ucrt-$arch $mingw_dir
+            # Temporary workaround: https://github.com/mstorsjo/llvm-mingw/issues/493
+            mkdir -p $mingw_dir/bin
+            ln -s $arch-w64-windows-gnu.cfg $mingw_dir/bin/$arch-pc-windows-gnu.cfg
+            ;;
+        *)
+            echo "Unrecognized archive type"
+            exit 1
+            ;;
+    esac
 
-    curl -o mingw.7z "${MIRRORS_BASE}/${mingw_archive}"
-    7z x -y mingw.7z > /dev/null
     ciCommandAddPath "$(cygpath -m "$(pwd)/${mingw_dir}/bin")"
 
-    # Initialize mingw for the user.
-    # This should be done by github but isn't for some reason.
-    # (see https://github.com/actions/runner-images/issues/12600)
-    /c/msys64/usr/bin/bash -lc ' '
+    # MSYS2 is not installed on AArch64 runners
+    if [[ "${CI_JOB_NAME}" != *aarch64-llvm* ]]; then
+        # Initialize mingw for the user.
+        # This should be done by github but isn't for some reason.
+        # (see https://github.com/actions/runner-images/issues/12600)
+        /c/msys64/usr/bin/bash -lc ' '
+    fi
 fi

src/etc/installer/msi/rust.wxs

@@ -38,6 +38,16 @@
             <?elseif $(env.CFG_CHANNEL)="dev" ?>
                 <?define UpgradeCode="231A9544-7E39-4A60-A069-0EB3CA4BAB2E" ?>
             <?endif ?>
+        <?elseif $(env.CFG_ABI)="LLVM" ?>
+            <?if $(env.CFG_CHANNEL)="stable" ?>
+                <?define UpgradeCode="BA2B2E96-F3E2-4DE9-8809-38C31382CC96" ?>
+            <?elseif $(env.CFG_CHANNEL)="beta" ?>
+                <?define UpgradeCode="44A2D96F-6CF2-4ED9-AE05-7CF0C3A7D0D9" ?>
+            <?elseif $(env.CFG_CHANNEL)="nightly" ?>
+                <?define UpgradeCode="FB0EEAE4-13FB-46BB-86E8-F9D00E6DA364" ?>
+            <?elseif $(env.CFG_CHANNEL)="dev" ?>
+                <?define UpgradeCode="73C94FB8-266F-48DC-A23B-B6E5DBDCF508" ?>
+            <?endif ?>
         <?endif ?>
         <?define PlatformProgramFilesFolder="ProgramFiles64Folder" ?>
     <?elseif $(sys.BUILDARCH)="x86" ?>
@@ -61,6 +71,16 @@
             <?elseif $(env.CFG_CHANNEL)="dev" ?>
                 <?define UpgradeCode="87DFC303-6492-4E9B-911E-56EAD56C5E58" ?>
             <?endif ?>
+        <?elseif $(env.CFG_ABI)="LLVM" ?>
+            <?if $(env.CFG_CHANNEL)="stable" ?>
+                <?define UpgradeCode="DB29CBDE-CDDF-4EC9-9C68-B6F00038EEDD" ?>
+            <?elseif $(env.CFG_CHANNEL)="beta" ?>
+                <?define UpgradeCode="AE1EF98B-1387-43BE-BE55-2310449D7E02" ?>
+            <?elseif $(env.CFG_CHANNEL)="nightly" ?>
+                <?define UpgradeCode="27B805BC-9C71-4198-A397-3082B1E708A7" ?>
+            <?elseif $(env.CFG_CHANNEL)="dev" ?>
+                <?define UpgradeCode="9DDD8D25-57C4-4410-AB35-A23A805AAD17" ?>
+            <?endif ?>
         <?endif ?>
         <?define PlatformProgramFilesFolder="ProgramFilesFolder" ?>
     <?else ?>