diff --git a/.github/workflows/build-toolchain.yml b/.github/workflows/build-toolchain.yml
index c18685d5..c1aaa9f1 100644
--- a/.github/workflows/build-toolchain.yml
+++ b/.github/workflows/build-toolchain.yml
@@ -185,8 +185,12 @@ jobs:
             ${{ matrix.container }}
           docker exec swiftwasm-ci-buildbot /bin/bash -lc 'env; cp -r /source/* /home/build-user/; ./swiftwasm-build/tools/build/ci.sh ${{ matrix.scheme }}'
 
+      - name: Extract installable archive from Docker container (wasm32-unknown-wasip1)
+        if: ${{ matrix.container != null && matrix.scheme != 'release-6.0' && matrix.scheme != 'release-6.1' }}
+        run: |
+          docker cp swiftwasm-ci-buildbot:/home/build-user/swift-wasm-${{ matrix.toolchain_channel }}-SNAPSHOT-wasm32-unknown-wasip1.artifactbundle.zip .
       - name: Extract installable archive from Docker container (wasm32-unknown-wasi)
-        if: ${{ matrix.container != null }}
+        if: ${{ matrix.container != null && !(matrix.scheme != 'release-6.0' && matrix.scheme != 'release-6.1') }}
         run: |
           docker cp swiftwasm-ci-buildbot:/home/build-user/swift-wasm-${{ matrix.toolchain_channel }}-SNAPSHOT-wasm32-unknown-wasi.artifactbundle.zip .
       # release-6.0 doesn't have wasm32-unknown-wasip1-threads SDK support yet
@@ -214,6 +218,11 @@ jobs:
           path: build-cache
           key: ${{ steps.cache_key.outputs.SCCACHE_KEY }}
 
+      - name: Upload Swift SDK artifact bundle (wasm32-unknown-wasip1)
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.scheme }}-wasm32-unknown-wasip1-artifactbundle
+          path: swift-wasm-${{ matrix.toolchain_channel }}-SNAPSHOT-wasm32-unknown-wasip1.artifactbundle.zip
       - name: Upload Swift SDK artifact bundle (wasm32-unknown-wasi)
         uses: actions/upload-artifact@v4
         with:
@@ -265,10 +274,7 @@ jobs:
         if: ${{ matrix.run_e2e_test }}
         run: |
           docker exec swiftwasm-ci-buildbot /bin/bash -lc \
-            "./llvm-project/llvm/utils/lit/lit.py \
-              --param swift-sdk=wasm32-unknown-wasi \
-              --param swift-sdks-path=./swift-sdk-generator/Bundles \
-              --param scheme=${{ matrix.scheme }} ./swiftwasm-build/test -vv"
+            "./swiftwasm-build/tools/build/run-e2e-test --scheme ${{ matrix.scheme }}"
 
       - name: Cleanup docker volume
         if: ${{ matrix.container != null }}
diff --git a/README.md b/README.md
index 7c378d8e..4dfe941c 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ $ ./tools/build/install-build-sdk.sh main
 # Checkout the Swift repositories in the parent directory (swiftwasm-source) and apply patches
 $ ./tools/git-swift-workspace --scheme main
 # Build the toolchain (this will take a while)
-$ ./tools/build/build-toolchain.sh main
+$ ./tools/build/build-toolchain main
 ```
 
 See [SwiftWasm book](https://book.swiftwasm.org/contribution-guide/how-to-build-toolchain.html) for more details about dependencies you need to install and how to build on Docker.
diff --git a/docs/upstreaming.md b/docs/upstreaming.md
index fa0a8c42..52fdb914 100644
--- a/docs/upstreaming.md
+++ b/docs/upstreaming.md
@@ -65,13 +65,7 @@ If it's first time to build or patch files are changed, you need to checkout the
 If you want to build the whole toolchain, run the following command:
 
 ```
-./tools/build/build-toolchain.sh
-```
-
-If you already built the compiler and want to build only the standard library for WebAssembly, run the following command:
-
-```
-./tools/build/build-toolchain.sh --skip-build-host-toolchain
+./tools/build/build-toolchain --scheme main
 ```
 
 ### Edit
diff --git a/schemes/main/build/build-foundation.sh b/schemes/main/build/build-foundation.sh
deleted file mode 100755
index f34f9625..00000000
--- a/schemes/main/build/build-foundation.sh
+++ /dev/null
@@ -1,55 +0,0 @@
-#!/bin/bash
-set -ex
-DESTINATION_TOOLCHAIN=$1
-LLVM_BIN_DIR=$2
-CLANG_BIN_DIR=$3
-SWIFT_BIN_DIR=$4
-WASI_SYSROOT_PATH=$5
-TRIPLE="$6"
-
-SOURCE_PATH="$(cd "$(dirname $0)/../../../.." && pwd)"
-BUILD_SDK_PATH="$SOURCE_PATH/build-sdk"
-LIBXML2_PATH="$BUILD_SDK_PATH/libxml2-$TRIPLE"
-
-FOUNDATION_BUILD="$SOURCE_PATH/build/WebAssembly/foundation-$TRIPLE"
-
-swift_extra_flags=""
-c_extra_flags=""
-if [[ "$TRIPLE" == "wasm32-unknown-wasip1-threads" ]]; then
-  swift_extra_flags="-Xcc -matomics -Xcc -mbulk-memory -Xcc -mthread-model -Xcc posix -Xcc -pthread -Xcc -ftls-model=local-exec"
-  c_extra_flags="-mthread-model posix -pthread -ftls-model=local-exec"
-fi
-
-cmake -G Ninja \
-  -D CMAKE_BUILD_TYPE="Release" \
-  -D CMAKE_SYSROOT="$WASI_SYSROOT_PATH" \
-  -D CMAKE_Swift_COMPILER="$SWIFT_BIN_DIR/swiftc" \
-  -D CMAKE_STAGING_PREFIX="$DESTINATION_TOOLCHAIN/usr" \
-  -D CMAKE_SYSTEM_NAME=WASI \
-  -D CMAKE_SYSTEM_PROCESSOR=wasm32 \
-  -D CMAKE_C_COMPILER_TARGET="$TRIPLE" \
-  -D CMAKE_CXX_COMPILER_TARGET="$TRIPLE" \
-  -D CMAKE_Swift_COMPILER_TARGET="$TRIPLE" \
-  -D CMAKE_C_COMPILER="$CLANG_BIN_DIR/clang" \
-  -D CMAKE_CXX_COMPILER="$CLANG_BIN_DIR/clang++" \
-  -D CMAKE_AR="$LLVM_BIN_DIR/llvm-ar" \
-  -D CMAKE_RANLIB="$LLVM_BIN_DIR/llvm-ranlib" \
-  -D LIBXML2_INCLUDE_DIR="$LIBXML2_PATH/include/libxml2" \
-  -D LIBXML2_LIBRARY="$LIBXML2_PATH/lib" \
-  -D BUILD_SHARED_LIBS=OFF \
-  -D FOUNDATION_BUILD_TOOLS=OFF \
-  -D CMAKE_Swift_COMPILER_FORCED=ON \
-  -D CMAKE_C_COMPILER_FORCED=ON \
-  -D CMAKE_CXX_COMPILER_FORCED=ON \
-  -D CMAKE_Swift_FLAGS="-sdk $WASI_SYSROOT_PATH -resource-dir $DESTINATION_TOOLCHAIN/usr/lib/swift_static $swift_extra_flags" \
-  -D CMAKE_C_FLAGS="-resource-dir $DESTINATION_TOOLCHAIN/usr/lib/swift_static/clang -B $LLVM_BIN_DIR $c_extra_flags" \
-  -D CMAKE_CXX_FLAGS="-fno-exceptions -resource-dir $DESTINATION_TOOLCHAIN/usr/lib/swift_static/clang -B $LLVM_BIN_DIR $c_extra_flags" \
-  -D _SwiftCollections_SourceDIR="$SOURCE_PATH/swift-collections" \
-  -D _SwiftFoundation_SourceDIR="$SOURCE_PATH/swift-foundation" \
-  -D _SwiftFoundationICU_SourceDIR="$SOURCE_PATH/swift-foundation-icu" \
-  -D SwiftFoundation_MACRO="$SWIFT_BIN_DIR/../lib/swift/host/plugins" \
-  -B "$FOUNDATION_BUILD" \
-  "${SOURCE_PATH}/swift-corelibs-foundation"
-  
-cmake --build "$FOUNDATION_BUILD"
-cmake --install "$FOUNDATION_BUILD"
diff --git a/schemes/main/build/build-target-toolchain.sh b/schemes/main/build/build-target-toolchain.sh
index 8e53202f..77f0c901 100755
--- a/schemes/main/build/build-target-toolchain.sh
+++ b/schemes/main/build/build-target-toolchain.sh
@@ -40,48 +40,22 @@ build_target_toolchain() {
   env DESTDIR="$TRIPLE_DESTDIR" \
     cmake --install "$TARGET_BUILD_ROOT/$STDLIB_PRODUCT-$HOST_SUFFIX" --prefix /usr
 
-  local swift_testing_build_dir="$TARGET_BUILD_ROOT/wasmswiftsdk-$HOST_SUFFIX/swift-testing/$TRIPLE"
-  # TODO: Remove this check once we build swift-testing for +threads target
-  if [[ -d "$swift_testing_build_dir" ]]; then
-    env DESTDIR="$TRIPLE_DESTDIR" \
-      cmake --install "$swift_testing_build_dir" --prefix /usr
-  fi
+  env DESTDIR="$TRIPLE_DESTDIR" \
+    cmake --install "$TARGET_BUILD_ROOT/wasmswiftsdk-$HOST_SUFFIX/swift-testing/$TRIPLE" --prefix /usr
+  env DESTDIR="$TRIPLE_DESTDIR" \
+    cmake --install "$TARGET_BUILD_ROOT/wasmswiftsdk-$HOST_SUFFIX/foundation/$TRIPLE" --prefix /usr
+  env DESTDIR="$TRIPLE_DESTDIR" \
+    cmake --install "$TARGET_BUILD_ROOT/wasmswiftsdk-$HOST_SUFFIX/xctest/$TRIPLE" --prefix /usr
 
   rm -rf "$TRIPLE_DESTDIR/usr/lib/swift_static/clang/lib/$COMPILER_RT_OS_DIR"
   # XXX: Is this the right way to install compiler-rt?
   cp -R "$TARGET_BUILD_ROOT/wasi-sysroot/$CLANG_MULTIARCH_TRIPLE/lib/$COMPILER_RT_OS_DIR" "$TRIPLE_DESTDIR/usr/lib/swift_static/clang/lib/$COMPILER_RT_OS_DIR"
 
-  # FIXME: Clang resource directory installation is not the best way currently.
-  # We currently have two copies of compiler headers copied from the base toolchain in
-  # lib/swift/clang and lib/swift_static/clang. This is because the Swift CMake build
-  # system installs the compiler headers from the native tools path when not building
-  # tools including clang compiler. This is not ideal but then where should we bring
-  # the compiler headers from? If we use the headers beside the base toolchain, clang
-  # driver will not be able to find libclang_rt.builtins-wasm32.a because it is not
-  # a part of the base toolchain. We need to find a better way to handle this.
-  local CLANG_VERSION
-  CLANG_VERSION="$(basename "$($CLANG_BIN_DIR/clang -print-resource-dir)")"
-  mkdir -p "$TRIPLE_DESTDIR/usr/lib/clang/$CLANG_VERSION/lib"
-  ln -sf "../../../swift_static/clang/lib/$COMPILER_RT_OS_DIR" "$TRIPLE_DESTDIR/usr/lib/clang/$CLANG_VERSION/lib/$COMPILER_RT_OS_DIR"
-}
-
-build_target_corelibs() {
-  local LLVM_BIN_DIR="$1"
-  local CLANG_BIN_DIR="$2"
-  local SWIFT_BIN_DIR="$3"
-  local TRIPLE="$4"
-  local SHORT_TRIPLE="$5"
-
-  local TRIPLE_DESTDIR="$TARGET_TOOLCHAIN_DESTDIR/$TRIPLE"
-  local CORELIBS_ARGS=(
-    "$TRIPLE_DESTDIR"
-    "$LLVM_BIN_DIR"
-    "$CLANG_BIN_DIR"
-    "$SWIFT_BIN_DIR"
-    "$WASI_SYSROOT_PATH/$SHORT_TRIPLE"
-  )
-  "$SCHEMES_BUILD_PATH/build-foundation.sh" "${CORELIBS_ARGS[@]}" "$TRIPLE"
-  "$SCHEMES_BUILD_PATH/build-xctest.sh" "${CORELIBS_ARGS[@]}" "$TRIPLE"
+  # FIXME: The following is a workaround for the issue with wrong libxml2.a path
+  local LIBXML2_PATH_TO_FIX="$TARGET_BUILD_ROOT/wasi-sysroot/$CLANG_MULTIARCH_TRIPLE/lib/libxml2.a"
+  if [[ -f "$LIBXML2_PATH_TO_FIX" ]]; then
+    cp "$LIBXML2_PATH_TO_FIX" "$TRIPLE_DESTDIR/usr/lib/swift_static/wasi/libxml2.a"
+  fi
 }
 
 main() {
@@ -137,7 +111,8 @@ main() {
 
   # NOTE: The llvm-cmake-options is a workaround for the issue on amazonlinux2
   # See https://github.com/apple/swift/commit/40c7268e8f7d402b27e3ad16a84180e07c37f92c
-  "$SOURCE_PATH/swift/utils/build-script" \
+  # NOTE: Add llvm-bin directory to PATH so that wasmstdlib.py can find FileCheck during tests
+  env PATH="$OPTIONS_LLVM_BIN:$OPTIONS_SWIFT_BIN:$PATH" "$SOURCE_PATH/swift/utils/build-script" \
     --build-subdir=WebAssembly \
     --release \
     --skip-build-llvm \
@@ -145,11 +120,13 @@ main() {
     --skip-build-cmark \
     --skip-build-benchmarks \
     --skip-early-swift-driver \
+    --wasmkit \
     --build-wasm-stdlib \
     --skip-test-wasm-stdlib \
     --native-swift-tools-path="$OPTIONS_SWIFT_BIN" \
     --native-clang-tools-path="$OPTIONS_CLANG_BIN" \
     --native-llvm-tools-path="$OPTIONS_LLVM_BIN" \
+    --build-runtime-with-host-compiler \
     --extra-cmake-options="\
       -DSWIFT_STDLIB_TRACING=NO \
       -DSWIFT_STDLIB_HAS_ASL=NO \
@@ -168,13 +145,10 @@ main() {
     "$OPTIONS_SWIFT_BIN"
   )
 
-  build_target_toolchain "${BUILD_TOOLS_ARGS[@]}" "wasm32-unknown-wasi" "wasi-wasm32" "wasm32-wasi" "wasmstdlib" "wasi"
+  build_target_toolchain "${BUILD_TOOLS_ARGS[@]}" "wasm32-unknown-wasip1" "wasip1-wasm32" "wasm32-wasip1" "wasmstdlib" "wasip1"
   build_target_toolchain "${BUILD_TOOLS_ARGS[@]}" "wasm32-unknown-wasip1-threads" "wasip1-threads-wasm32" "wasm32-wasip1-threads" "wasmthreadsstdlib" "wasip1"
 
   rsync -av "$WASI_SYSROOT_PATH/" "$PACKAGING_DIR/wasi-sysroot/"
-
-  build_target_corelibs "${BUILD_TOOLS_ARGS[@]}" "wasm32-unknown-wasi" "wasm32-wasi"
-  build_target_corelibs "${BUILD_TOOLS_ARGS[@]}" "wasm32-unknown-wasip1-threads" "wasm32-wasip1-threads"
 }
 
 main "$@"
diff --git a/schemes/main/build/build-xctest.sh b/schemes/main/build/build-xctest.sh
deleted file mode 100755
index 472cc664..00000000
--- a/schemes/main/build/build-xctest.sh
+++ /dev/null
@@ -1,39 +0,0 @@
-#!/bin/bash
-set -ex
-DESTINATION_TOOLCHAIN=$1
-LLVM_BIN_DIR=$2
-CLANG_BIN_DIR=$3
-SWIFT_BIN_DIR=$4
-WASI_SYSROOT_PATH=$5
-TRIPLE="$6"
-
-SOURCE_PATH="$(cd "$(dirname $0)/../../../../" && pwd)"
-SCHEME_BUILD_PATH="$(cd "$(dirname $0)" && pwd)"
-
-BUILD_DIR="$SOURCE_PATH/build/WebAssembly/xctest-$TRIPLE"
-
-mkdir -p $BUILD_DIR
-cd $BUILD_DIR
-
-swift_extra_flags=""
-if [[ "$TRIPLE" == "wasm32-unknown-wasip1-threads" ]]; then
-  swift_extra_flags="-Xcc -matomics -Xcc -mbulk-memory -Xcc -mthread-model -Xcc posix -Xcc -pthread -Xcc -ftls-model=local-exec"
-fi
-
-cmake -G Ninja \
-  -DCMAKE_BUILD_TYPE="Release" \
-  -DCMAKE_SYSROOT="$WASI_SYSROOT_PATH" \
-  -DCMAKE_STAGING_PREFIX="$DESTINATION_TOOLCHAIN/usr" \
-  -DCMAKE_Swift_COMPILER="$SWIFT_BIN_DIR/swiftc" \
-  -DCMAKE_TOOLCHAIN_FILE="$SCHEME_BUILD_PATH/toolchain-wasi.cmake" \
-  -DTRIPLE="$TRIPLE" \
-  -DLLVM_BIN="$LLVM_BIN_DIR" \
-  -DCLANG_BIN="$CLANG_BIN_DIR" \
-  -DBUILD_SHARED_LIBS=OFF \
-  -DCMAKE_Swift_COMPILER_FORCED=ON \
-  -DCMAKE_Swift_FLAGS="-sdk $WASI_SYSROOT_PATH -resource-dir $DESTINATION_TOOLCHAIN/usr/lib/swift_static $swift_extra_flags" \
-  -DSWIFT_FOUNDATION_PATH=$DESTINATION_TOOLCHAIN/usr/lib/swift_static/wasi/wasm32 \
-  "${SOURCE_PATH}/swift-corelibs-xctest"
-  
-ninja -v
-ninja -v install
diff --git a/schemes/main/build/run-test.sh b/schemes/main/build/run-test.sh
index aa92d6f8..701e6c60 100755
--- a/schemes/main/build/run-test.sh
+++ b/schemes/main/build/run-test.sh
@@ -2,9 +2,4 @@
 
 set -euxo pipefail
 
-SOURCE_PATH="$(cd "$(dirname "$0")/../../../.." && pwd)"
-BUILD_DIR="$SOURCE_PATH/build"
-TARGET_BUILD_ROOT="$BUILD_DIR/WebAssembly"
-
-HOST_SUFFIX=$(find "$TARGET_BUILD_ROOT" -name "wasmstdlib-*" -exec basename {} \; | sed 's/wasmstdlib-//')
-env "PATH=$TARGET_BUILD_ROOT/llvm-$HOST_SUFFIX/bin:$BUILD_DIR/llvm-tools/bin:$PATH" "LIT_FILTER_OUT=(IRGen/|embedded/)" ninja check-swift-wasi-wasm32-custom -C "$TARGET_BUILD_ROOT/wasmstdlib-$HOST_SUFFIX"
+echo "Skipping test because we now run tests in build-script"
diff --git a/schemes/main/manifest.json b/schemes/main/manifest.json
index 47605521..8867f7f9 100644
--- a/schemes/main/manifest.json
+++ b/schemes/main/manifest.json
@@ -1,9 +1,6 @@
 {
-  "base-tag": "swift-DEVELOPMENT-SNAPSHOT-2025-07-18-a",
+  "base-tag": "swift-DEVELOPMENT-SNAPSHOT-2025-07-23-a",
   "icu4c": [],
-  "libxml2": [
-    "https://github.com/swiftwasm/libxml2-wasm/releases/download/2.0.0/libxml2-wasm32-unknown-wasi.tar.gz",
-    "https://github.com/swiftwasm/libxml2-wasm/releases/download/2.0.0/libxml2-wasm32-unknown-wasip1-threads.tar.gz"
-  ],
+  "libxml2": [],
   "swift-org-download-channel": "development"
 }
diff --git a/test/swift-sdk/foundation/ProcessInfo.swift b/test/swift-sdk/foundation/ProcessInfo.swift
index 74053dd1..1b1ef371 100644
--- a/test/swift-sdk/foundation/ProcessInfo.swift
+++ b/test/swift-sdk/foundation/ProcessInfo.swift
@@ -1,8 +1,6 @@
 // RUN: %{target_simple_swift_build}
 // RUN: %{wasm_run} --dir %t.dir::/tmp %t.dir/.build/debug/Check.wasm | %{FileCheck} %s
 // REQUIRES: FileCheck && scheme=main
-// XFAIL: scheme=main
-// https://github.com/swiftlang/swift-foundation/pull/1447
 
 import Foundation
 
diff --git a/tools/build/build-toolchain b/tools/build/build-toolchain
new file mode 100755
index 00000000..93a25182
--- /dev/null
+++ b/tools/build/build-toolchain
@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+
+import sys
+import argparse
+import pathlib
+import subprocess
+from build_support.actions import derive_options_from_args, REPO_ROOT, DownloadBaseSnapshotAction
+
+
+def main():
+    parser = argparse.ArgumentParser(description='Build the Swift toolchain')
+    options = derive_options_from_args(sys.argv[1:], parser)
+
+    # Calculate paths
+    repo_path = pathlib.Path(REPO_ROOT)
+    source_path = repo_path.parent
+    tools_build_path = pathlib.Path(__file__).parent
+
+    build_dir = source_path / "build"
+    cross_compiler_destdir = pathlib.Path(DownloadBaseSnapshotAction.toolchain_path(options))
+
+    # Install base toolchain
+    print("=====> Installing base toolchain")
+    subprocess.check_call([
+        str(tools_build_path / "install-base-toolchain"),
+        "--scheme", options.scheme
+    ])
+
+    # Build LLVM tools
+    print("=====> Building LLVM tools")
+    subprocess.check_call([
+        str(tools_build_path / "build-llvm-tools"),
+        "--toolchain", str(cross_compiler_destdir)
+    ])
+
+    # Build target toolchain
+    print("=====> Building target toolchain")
+    scheme_build_script = repo_path / "schemes" / options.scheme / "build" / "build-target-toolchain.sh"
+
+    subprocess.check_call([
+        str(scheme_build_script),
+        "--llvm-bin", str(build_dir / "llvm-tools" / "bin"),
+        "--clang-bin", str(cross_compiler_destdir / "usr" / "bin"),
+        "--swift-bin", str(cross_compiler_destdir / "usr" / "bin"),
+        "--scheme", options.scheme
+    ])
+
+
+if __name__ == '__main__':
+    main()
diff --git a/tools/build/build-toolchain.sh b/tools/build/build-toolchain.sh
deleted file mode 100755
index 1823d9a3..00000000
--- a/tools/build/build-toolchain.sh
+++ /dev/null
@@ -1,23 +0,0 @@
-#!/bin/bash
-
-set -eux -o pipefail
-
-REPO_PATH="$(cd "$(dirname $0)/../.." && pwd)"
-SOURCE_PATH="$REPO_PATH/.."
-SCHEME="${1:?"scheme is not specified"}"
-
-TOOLS_BUILD_PATH="$(cd "$(dirname "$0")" && pwd)"
-
-BUILD_DIR="$SOURCE_PATH/build"
-PACKAGING_DIR="$BUILD_DIR/Packaging"
-CROSS_COMPILER_DESTDIR=$PACKAGING_DIR/base-snapshot
-
-"$TOOLS_BUILD_PATH/install-base-toolchain" --scheme "$SCHEME"
-"$TOOLS_BUILD_PATH/build-llvm-tools" --toolchain "$CROSS_COMPILER_DESTDIR"
-
-"$REPO_PATH/schemes/$SCHEME/build/build-target-toolchain.sh" \
-  --llvm-bin "$BUILD_DIR/llvm-tools/bin" \
-  --clang-bin "$CROSS_COMPILER_DESTDIR/usr/bin" \
-  --swift-bin "$CROSS_COMPILER_DESTDIR/usr/bin" \
-  --scheme "$SCHEME"
-
diff --git a/tools/build/build_support/actions.py b/tools/build/build_support/actions.py
index fb16c6d1..126dce2b 100644
--- a/tools/build/build_support/actions.py
+++ b/tools/build/build_support/actions.py
@@ -114,16 +114,25 @@ def run(self):
             self.system('git', '-C', f'../{repo}', 'checkout', rev)
 
 class DownloadBaseSnapshotAction(Action):
+
+    @staticmethod
+    def toolchains_dir():
+        return os.path.join(REPO_ROOT, '..', 'build', 'Packaging', 'base-toolchain')
+
+    @staticmethod
+    def toolchain_path(options):
+        return os.path.join(DownloadBaseSnapshotAction.toolchains_dir(), options.tag)
+
     def run(self):
         platform_info = platform.PlatformInfo.derive()
         snapshot_url, tarball_name = platform_info.snapshot_url(self.options.swift_org_download_channel, self.options.tag)
         extension = platform_info.package_extension
 
-        tarball_path = os.path.join('..', 'build', 'Packaging', f'base-snapshot.{extension}')
-        base_snapshot_dir = os.path.join('..', 'build', 'Packaging', 'base-snapshot')
+        base_toolchain_dir = DownloadBaseSnapshotAction.toolchain_path(self.options)
+        tarball_path = os.path.join(os.path.dirname(base_toolchain_dir), tarball_name)
 
-        if os.path.exists(os.path.join(base_snapshot_dir, 'usr')):
-            print(f"=====> Base snapshot '{base_snapshot_dir}' already exists")
+        if os.path.exists(os.path.join(base_toolchain_dir, 'usr')):
+            print(f"=====> Base snapshot '{base_toolchain_dir}' already exists")
             return
 
         if not os.path.exists(tarball_path):
@@ -132,15 +141,15 @@ def run(self):
             self.system('curl', '--fail', '-L', '-o', tarball_path, snapshot_url)
 
         print(f"=====> Unpacking base snapshot {tarball_name}")
-        os.makedirs(base_snapshot_dir, exist_ok=True)
+        os.makedirs(base_toolchain_dir, exist_ok=True)
         if extension == "tar.gz":
-            self.system('tar', '-C', base_snapshot_dir, '--strip-components', '1', '-xzf', tarball_path)
+            self.system('tar', '-C', base_toolchain_dir, '--strip-components', '1', '-xzf', tarball_path)
         elif extension == "pkg":
             import tempfile
             with tempfile.TemporaryDirectory() as tmpdir:
                 self.system('xar', '-xf', tarball_path, '-C', tmpdir)
                 old_cwd = os.getcwd()
-                os.chdir(base_snapshot_dir)
+                os.chdir(base_toolchain_dir)
                 pkg_name = tarball_name.replace(".pkg", "-package.pkg")
                 self.system('cpio', '-i', '-I', os.path.join(tmpdir, pkg_name, 'Payload'))
                 os.chdir(old_cwd)
diff --git a/tools/build/build_support/llvm_tools.py b/tools/build/build_support/llvm_tools.py
index eb47da43..6e2f7e0e 100644
--- a/tools/build/build_support/llvm_tools.py
+++ b/tools/build/build_support/llvm_tools.py
@@ -8,4 +8,6 @@
     # These tools are used by Swift test suite
     'llvm-nm',
     'FileCheck',
-]
\ No newline at end of file
+    'split-file',
+    'not',
+]
diff --git a/tools/build/ci.sh b/tools/build/ci.sh
index f75c44d9..584e19d7 100755
--- a/tools/build/ci.sh
+++ b/tools/build/ci.sh
@@ -34,6 +34,6 @@ install_sccache_if_needed() {
 install_sccache_if_needed
 export PATH="$SCCACHE_INSTALL_PATH:$PATH"
 
-$TOOLS_BUILD_PATH/build-toolchain.sh "$SCHEME"
+$TOOLS_BUILD_PATH/build-toolchain --scheme "$SCHEME"
 
 $TOOLS_BUILD_PATH/package-toolchain --scheme "$SCHEME" --daily-snapshot
diff --git a/tools/build/package-toolchain b/tools/build/package-toolchain
index 9fe19402..4110c2aa 100755
--- a/tools/build/package-toolchain
+++ b/tools/build/package-toolchain
@@ -51,7 +51,10 @@ def copy_icu_libs(scheme, build_sdk_path, dist_toolchain_path, target_triple):
         shutil.copy(os.path.join(icu_lib_dir, lib), dest_path)
 
 
-def copy_libxml2_libs(build_sdk_path, dist_toolchain_path, target_triple):
+def copy_libxml2_libs(scheme, build_sdk_path, dist_toolchain_path, target_triple):
+    if scheme not in ["release-6.0", "release-6.1"]:
+        # Recent channels install libxml2 in wasi-sysroot by default
+        return
     import shutil
     lib_dir = os.path.join(build_sdk_path, f"libxml2-{target_triple}", 'lib')
     if not os.path.exists(lib_dir):
@@ -83,7 +86,7 @@ class PackageSwiftSDKAction(Action):
     def run(self):
         build_sdk_path = os.path.join('..', 'build-sdk')
         copy_icu_libs(self.options.scheme, build_sdk_path, self.target_toolchain_path, self.target_triple)
-        copy_libxml2_libs(build_sdk_path, self.target_toolchain_path, self.target_triple)
+        copy_libxml2_libs(self.options.scheme, build_sdk_path, self.target_toolchain_path, self.target_triple)
         self.make_swift_sdk(
             self.target_toolchain_path,
             self.wasi_sysroot_path,
@@ -207,8 +210,12 @@ def main():
 
     toolchain_channel = derive_toolchain_channel(options.scheme)
     triples = [
-        ["wasm32-unknown-wasi", "wasm32-wasi"],
+        ["wasm32-unknown-wasip1", "wasm32-wasip1"],
     ]
+    if options.scheme in ["release-6.0", "release-6.1"]:
+        triples = [
+            ["wasm32-unknown-wasi", "wasm32-wasi"],
+        ]
     if options.scheme not in ["release-6.0"]:
         triples += [
             ["wasm32-unknown-wasip1-threads", "wasm32-wasip1-threads"]
diff --git a/tools/build/run-e2e-test b/tools/build/run-e2e-test
new file mode 100755
index 00000000..374c48c6
--- /dev/null
+++ b/tools/build/run-e2e-test
@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+
+import sys
+import argparse
+import pathlib
+import subprocess
+from build_support.actions import derive_options_from_args, REPO_ROOT, DownloadBaseSnapshotAction
+
+
+def default_swift_sdk(options, swift_sdks_path: pathlib.Path):
+    """Return the default target triple based on the scheme."""
+    import json
+    for artifact_bundle in swift_sdks_path.iterdir():
+        if not artifact_bundle.is_dir() or not artifact_bundle.name.endswith('.artifactbundle'):
+            # Skip if not ending with .artifactbundle
+            continue
+        info_json = artifact_bundle / 'info.json'
+        if not info_json.is_file():
+            continue
+        try:
+            with info_json.open('r') as f:
+                info = json.load(f)
+
+            sdk_ids = info.get('artifacts', {}).keys()
+            for sdk_id in sdk_ids:
+                if sdk_id.endswith("wasm32-unknown-wasip1") or sdk_id.endswith("wasm32-unknown-wasi"):
+                    return sdk_id
+        except Exception as e:
+            print(f"Error reading {info_json}: {e}", file=sys.stderr)
+            continue
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description='Run e2e integration tests for Swift SDK')
+    parser.add_argument('--swift-sdk', default=None,
+                        help='Swift SDK identifier (default: wasm32-unknown-wasip1)')
+    parser.add_argument('args', nargs=argparse.REMAINDER,
+                        help='Extra arguments to pass to lit.py')
+    options = derive_options_from_args(sys.argv[1:], parser)
+
+    extra_lit_args = options.args
+    if len(extra_lit_args) > 0 and extra_lit_args[0] == "--":
+        extra_lit_args = extra_lit_args[1:]
+
+    repo_path = pathlib.Path(REPO_ROOT)
+    base_toolchain_path = DownloadBaseSnapshotAction.toolchain_path(options)
+    lit_py_path = repo_path.parent / "llvm-project" / "llvm" / "utils" / "lit" / "lit.py"
+    swift_sdks_path = repo_path.parent / "swift-sdk-generator" / "Bundles"
+    swift_sdk = options.swift_sdk or default_swift_sdk(options, swift_sdks_path)
+
+    # Build lit command
+    lit_cmd = [
+        str(lit_py_path),
+        "--param", f"swift-sdk={swift_sdk}",
+        "--param", f"scheme={options.scheme}",
+        "--param", f"base-toolchain-path={base_toolchain_path}",
+        "--param", f"swift-sdks-path={swift_sdks_path}",
+    ]
+    test_dir = repo_path / "test"
+    lit_cmd.append(str(test_dir))
+    lit_cmd.extend(extra_lit_args)
+
+    print("=====> Running e2e integration tests")
+    print(f"Command: {' '.join(lit_cmd)}")
+
+    # Run the tests
+    try:
+        subprocess.check_call(lit_cmd)
+        print("=====> e2e tests completed successfully")
+    except subprocess.CalledProcessError as e:
+        print(f"=====> e2e tests failed with exit code {e.returncode}")
+        sys.exit(e.returncode)
+
+
+if __name__ == '__main__':
+    main()