From 6409c12dc71ab20109b75f75314c176d76c7d77f Mon Sep 17 00:00:00 2001
From: Mengwei Liu <mengweiliu600267@gmail.com>
Date: Mon, 3 Nov 2025 23:09:14 -0800
Subject: [PATCH 01/14] Move QNN SDK into backends/qualcomm/CMakeLists.txt

---
 backends/qualcomm/CMakeLists.txt              | 43 ++++++--
 backends/qualcomm/scripts/download_qnn_sdk.py | 45 ++++++++-
 setup.py                                      | 99 ++++---------------
 tools/cmake/preset/pybind.cmake               |  3 +
 4 files changed, 102 insertions(+), 88 deletions(-)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index 07166b92ea2..aa417d5995e 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -23,13 +23,34 @@ get_filename_component(
   _common_include_directories "${EXECUTORCH_SOURCE_DIR}/.." ABSOLUTE
 )
 
-if(NOT DEFINED QNN_SDK_ROOT)
-  message(
-    FATAL_ERROR
-      "Please define QNN_SDK_ROOT, e.g. cmake <..> -DQNN_SDK_ROOT=<...>"
+if(EXECUTORCH_BUILD_PYBIND)
+  find_package(Python3 COMPONENTS Interpreter REQUIRED)
+  message(STATUS "QNN_SDK_ROOT not provided, downloading Qualcomm SDK")
+  execute_process(
+    COMMAND
+      ${Python3_EXECUTABLE}
+      ${EXECUTORCH_SOURCE_DIR}/backends/qualcomm/scripts/download_qnn_sdk.py
+      --print-sdk-path
+    WORKING_DIRECTORY ${EXECUTORCH_SOURCE_DIR}
+    RESULT_VARIABLE _qnn_sdk_download_result
+    OUTPUT_VARIABLE _qnn_sdk_download_output
+    ERROR_VARIABLE _qnn_sdk_download_error
+    OUTPUT_STRIP_TRAILING_WHITESPACE
   )
-elseif(CMAKE_TOOLCHAIN_FILE MATCHES ".*(iOS|ios\.toolchain)\.cmake$")
-  message(FATAL_ERROR "ios is not supported by Qualcomm AI Engine Direct")
+  if(NOT _qnn_sdk_download_result EQUAL 0
+      OR _qnn_sdk_download_output STREQUAL "")
+    message(
+      FATAL_ERROR
+        "Failed to download Qualcomm SDK. stdout: ${_qnn_sdk_download_output}\n"
+        "stderr: ${_qnn_sdk_download_error}"
+    )
+  endif()
+  set(
+    QNN_SDK_ROOT
+    ${_qnn_sdk_download_output}
+    CACHE PATH "Qualcomm SDK root directory" FORCE
+  )
+  set(ENV{QNN_SDK_ROOT} ${QNN_SDK_ROOT})
 endif()
 
 message(STATUS "Using qnn sdk root ${QNN_SDK_ROOT}")
@@ -214,7 +235,9 @@ add_subdirectory(
 install(
   TARGETS qnn_executorch_backend
   EXPORT ExecuTorchTargets
-  DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm
+  RUNTIME DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm
 )
 
 # QNN pybind
@@ -275,4 +298,10 @@ if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "x86_64")
     ${QNN_EXECUTORCH_ROOT_DIR}/aot/python
     ${CMAKE_CURRENT_BINARY_DIR}/qnn_executorch/python
   )
+
+  install(
+    TARGETS PyQnnManagerAdaptor PyQnnWrapperAdaptor
+    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm/python
+    RUNTIME DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm/python
+  )
 endif()
diff --git a/backends/qualcomm/scripts/download_qnn_sdk.py b/backends/qualcomm/scripts/download_qnn_sdk.py
index 747524a0e5b..1bd844e2288 100644
--- a/backends/qualcomm/scripts/download_qnn_sdk.py
+++ b/backends/qualcomm/scripts/download_qnn_sdk.py
@@ -1,4 +1,4 @@
-# Add these imports for additional logging
+import argparse
 import ctypes
 import logging
 import os
@@ -592,3 +592,46 @@ def install_qnn_sdk() -> bool:
 
     # libc++ and QNN SDK setup
     return _ensure_libcxx_stack() and _ensure_qnn_sdk_lib()
+
+
+def main(argv: Optional[List[str]] = None) -> int:
+    parser = argparse.ArgumentParser(
+        description="Helper utility for Qualcomm SDK staging."
+    )
+    parser.add_argument(
+        "--dst-folder",
+        type=pathlib.Path,
+        default=SDK_DIR,
+        help="Destination directory for the Qualcomm SDK.",
+    )
+    parser.add_argument(
+        "--print-sdk-path",
+        action="store_true",
+        help="Print the resolved Qualcomm SDK path to stdout.",
+    )
+    parser.add_argument(
+        "--install-sdk",
+        action="store_true",
+        help="Ensure the SDK and runtime libraries are staged and loaded.",
+    )
+    args = parser.parse_args(argv)
+
+    logging.basicConfig(level=logging.INFO)
+
+    sdk_path: Optional[pathlib.Path]
+    if args.install_sdk:
+        if not install_qnn_sdk():
+            return 1
+        sdk_path = pathlib.Path(os.environ.get("QNN_SDK_ROOT", args.dst_folder))
+    else:
+        sdk_path = _download_qnn_sdk(dst_folder=args.dst_folder)
+        if sdk_path is None:
+            return 1
+
+    if args.print_sdk_path and sdk_path is not None:
+        print(sdk_path)
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/setup.py b/setup.py
index 8e75ea47cd6..723bca484f2 100644
--- a/setup.py
+++ b/setup.py
@@ -57,8 +57,6 @@
 import site
 import subprocess
 import sys
-import sysconfig
-import tempfile
 
 from distutils import log  # type: ignore[import-not-found]
 from distutils.sysconfig import get_python_lib  # type: ignore[import-not-found]
@@ -463,84 +461,6 @@ def run(self):
         if self._ran_build:
             return
 
-        try:
-            # Following code is for building the Qualcomm backend.
-            from backends.qualcomm.scripts.download_qnn_sdk import (
-                _download_qnn_sdk,
-                is_linux_x86,
-            )
-
-            if is_linux_x86():
-                os.environ["EXECUTORCH_BUILDING_WHEEL"] = "1"
-
-                with tempfile.TemporaryDirectory() as tmpdir:
-                    tmp_path = Path(tmpdir)
-                    sdk_path = _download_qnn_sdk(dst_folder=tmp_path)
-
-                    if not sdk_path:
-                        raise RuntimeError(
-                            "Qualcomm SDK not found, cannot build backend"
-                        )
-
-                    # Determine paths
-                    prj_root = Path(__file__).parent.resolve()
-                    build_sh = prj_root / "backends/qualcomm/scripts/build.sh"
-                    build_root = prj_root / "build-x86"
-
-                    if not build_sh.exists():
-                        raise FileNotFoundError(f"{build_sh} not found")
-
-                    # Run build.sh with SDK path exported
-                    env = dict(**os.environ)
-                    env["QNN_SDK_ROOT"] = str(sdk_path)
-                    subprocess.check_call(
-                        [
-                            str(build_sh),
-                            "--skip_linux_android",
-                            "--skip_linux_embedded",
-                        ],
-                        env=env,
-                    )
-
-                    # Copy the main .so into the wheel package
-                    so_src = (
-                        build_root / "backends/qualcomm/libqnn_executorch_backend.so"
-                    )
-                    so_dst = Path(
-                        self.get_ext_fullpath(
-                            "executorch.backends.qualcomm.qnn_backend"
-                        )
-                    )
-                    self.mkpath(str(so_dst.parent))  # ensure destination exists
-                    self.copy_file(str(so_src), str(so_dst))
-                    logging.info(f"Copied Qualcomm backend: {so_src} -> {so_dst}")
-
-                    # Copy Python adaptor .so files
-                    ext_suffix = sysconfig.get_config_var("EXT_SUFFIX")
-
-                    so_files = [
-                        (
-                            "executorch.backends.qualcomm.python.PyQnnManagerAdaptor",
-                            prj_root
-                            / f"backends/qualcomm/python/PyQnnManagerAdaptor{ext_suffix}",
-                        ),
-                        (
-                            "executorch.backends.qualcomm.python.PyQnnWrapperAdaptor",
-                            prj_root
-                            / f"backends/qualcomm/python/PyQnnWrapperAdaptor{ext_suffix}",
-                        ),
-                    ]
-
-                    for module_name, so_src in so_files:
-                        so_dst = Path(self.get_ext_fullpath(module_name))
-                        self.mkpath(str(so_dst.parent))
-                        self.copy_file(str(so_src), str(so_dst))
-                        logging.info(f"Copied Qualcomm backend: {so_src} -> {so_dst}")
-
-        except ImportError:
-            logging.error("Fail to build Qualcomm backend")
-            logging.exception("Import error")
-
         if self.editable_mode:
             self._ran_build = True
             self.run_command("build")
@@ -924,5 +844,24 @@ def run(self):  # noqa C901
             dst="executorch/data/lib/",
             dependent_cmake_flags=[],
         ),
+        BuiltFile(
+            src_dir="%CMAKE_CACHE_DIR%/backends/qualcomm/%BUILD_TYPE%/",
+            src_name="qnn_executorch_backend",
+            dst="executorch/backends/qualcomm/",
+            is_dynamic_lib=True,
+            dependent_cmake_flags=["EXECUTORCH_BUILD_QNN"],
+        ),
+        BuiltExtension(
+            src_dir="%CMAKE_CACHE_DIR%/backends/qualcomm/python/%BUILD_TYPE%/",
+            src="PyQnnManagerAdaptor.*",
+            modpath="executorch.backends.qualcomm.python.PyQnnManagerAdaptor",
+            dependent_cmake_flags=["EXECUTORCH_BUILD_QNN"],
+        ),
+        BuiltExtension(
+            src_dir="%CMAKE_CACHE_DIR%/backends/qualcomm/python/%BUILD_TYPE%/",
+            src="PyQnnWrapperAdaptor.*",
+            modpath="executorch.backends.qualcomm.python.PyQnnWrapperAdaptor",
+            dependent_cmake_flags=["EXECUTORCH_BUILD_QNN"],
+        ),
     ],
 )
diff --git a/tools/cmake/preset/pybind.cmake b/tools/cmake/preset/pybind.cmake
index c71c10ad01f..7c4de793721 100644
--- a/tools/cmake/preset/pybind.cmake
+++ b/tools/cmake/preset/pybind.cmake
@@ -35,6 +35,9 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
   set_overridable_option(EXECUTORCH_BUILD_EXTENSION_TRAINING ON)
   set_overridable_option(EXECUTORCH_BUILD_EXTENSION_LLM_RUNNER ON)
   set_overridable_option(EXECUTORCH_BUILD_EXTENSION_LLM ON)
+  if(CMAKE_SYSTEM_PROCESSOR MATCHES "^(x86_64|amd64|i.86)$")
+    set_overridable_option(EXECUTORCH_BUILD_QNN ON)
+  endif()
 elseif(CMAKE_SYSTEM_NAME STREQUAL "Windows" OR CMAKE_SYSTEM_NAME STREQUAL
                                                "WIN32"
 )

From deb216b2ee44ff7046654a608d2f9284f3ecb452 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <mengweiliu600267@gmail.com>
Date: Mon, 3 Nov 2025 23:17:02 -0800
Subject: [PATCH 02/14] Lint

---
 backends/qualcomm/CMakeLists.txt | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index aa417d5995e..24ed1ed404d 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -24,7 +24,11 @@ get_filename_component(
 )
 
 if(EXECUTORCH_BUILD_PYBIND)
-  find_package(Python3 COMPONENTS Interpreter REQUIRED)
+  find_package(
+    Python3
+    COMPONENTS Interpreter
+    REQUIRED
+  )
   message(STATUS "QNN_SDK_ROOT not provided, downloading Qualcomm SDK")
   execute_process(
     COMMAND
@@ -37,18 +41,18 @@ if(EXECUTORCH_BUILD_PYBIND)
     ERROR_VARIABLE _qnn_sdk_download_error
     OUTPUT_STRIP_TRAILING_WHITESPACE
   )
-  if(NOT _qnn_sdk_download_result EQUAL 0
-      OR _qnn_sdk_download_output STREQUAL "")
+  if(NOT _qnn_sdk_download_result EQUAL 0 OR _qnn_sdk_download_output STREQUAL
+                                             ""
+  )
     message(
       FATAL_ERROR
         "Failed to download Qualcomm SDK. stdout: ${_qnn_sdk_download_output}\n"
         "stderr: ${_qnn_sdk_download_error}"
     )
   endif()
-  set(
-    QNN_SDK_ROOT
-    ${_qnn_sdk_download_output}
-    CACHE PATH "Qualcomm SDK root directory" FORCE
+  set(QNN_SDK_ROOT
+      ${_qnn_sdk_download_output}
+      CACHE PATH "Qualcomm SDK root directory" FORCE
   )
   set(ENV{QNN_SDK_ROOT} ${QNN_SDK_ROOT})
 endif()
@@ -301,7 +305,9 @@ if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "x86_64")
 
   install(
     TARGETS PyQnnManagerAdaptor PyQnnWrapperAdaptor
-    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm/python
-    RUNTIME DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm/python
+    LIBRARY
+      DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm/python
+    RUNTIME
+      DESTINATION ${CMAKE_INSTALL_LIBDIR}/executorch/backends/qualcomm/python
   )
 endif()

From 73be53a91a17ccf5f0669551fc3db03611419263 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Tue, 4 Nov 2025 09:44:10 -0800
Subject: [PATCH 03/14] Fix src path

---
 setup.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/setup.py b/setup.py
index 723bca484f2..71aa4c543d4 100644
--- a/setup.py
+++ b/setup.py
@@ -757,6 +757,11 @@ def run(self):  # noqa C901
             cmake_build_args += ["--target", "custom_ops_aot_lib"]
             cmake_build_args += ["--target", "quantized_ops_aot_lib"]
 
+        if cmake_cache.is_enabled("EXECUTORCH_BUILD_QNN"):
+            cmake_build_args += ["--target", "qnn_executorch_backend"]
+            cmake_build_args += ["--target", "PyQnnManagerAdaptor"]
+            cmake_build_args += ["--target", "PyQnnWrapperAdaptor"]
+
         # Set PYTHONPATH to the location of the pip package.
         os.environ["PYTHONPATH"] = (
             site.getsitepackages()[0] + ";" + os.environ.get("PYTHONPATH", "")
@@ -852,13 +857,13 @@ def run(self):  # noqa C901
             dependent_cmake_flags=["EXECUTORCH_BUILD_QNN"],
         ),
         BuiltExtension(
-            src_dir="%CMAKE_CACHE_DIR%/backends/qualcomm/python/%BUILD_TYPE%/",
+            src_dir="%CMAKE_CACHE_DIR%/backends/qualcomm/%BUILD_TYPE%/",
             src="PyQnnManagerAdaptor.*",
             modpath="executorch.backends.qualcomm.python.PyQnnManagerAdaptor",
             dependent_cmake_flags=["EXECUTORCH_BUILD_QNN"],
         ),
         BuiltExtension(
-            src_dir="%CMAKE_CACHE_DIR%/backends/qualcomm/python/%BUILD_TYPE%/",
+            src_dir="%CMAKE_CACHE_DIR%/backends/qualcomm/%BUILD_TYPE%/",
             src="PyQnnWrapperAdaptor.*",
             modpath="executorch.backends.qualcomm.python.PyQnnWrapperAdaptor",
             dependent_cmake_flags=["EXECUTORCH_BUILD_QNN"],

From d9f7233841c587a80c4caedf311d1ac76a8e6c05 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Tue, 4 Nov 2025 16:14:53 -0800
Subject: [PATCH 04/14] Fix rpath

---
 CMakeLists.txt                   | 16 +++++----
 backends/qualcomm/CMakeLists.txt | 62 ++++++++++++++++++--------------
 2 files changed, 45 insertions(+), 33 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 51573d276b3..cd6a16b94b7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -801,6 +801,9 @@ if(EXECUTORCH_BUILD_PYBIND)
       torch
   )
 
+  # RPATH for _portable_lib.so
+  set(_portable_lib_rpath "$ORIGIN/../../../torch/lib")
+
   if(EXECUTORCH_BUILD_EXTENSION_MODULE)
     # Always use static linking for pybindings to avoid runtime symbol
     # resolution issues
@@ -835,6 +838,7 @@ if(EXECUTORCH_BUILD_PYBIND)
 
   if(EXECUTORCH_BUILD_QNN)
     list(APPEND _dep_libs qnn_executorch_backend)
+    string(APPEND _portable_lib_rpath ":$ORIGIN/../../backends/qualcomm")
   endif()
 
   if(EXECUTORCH_BUILD_ENN)
@@ -886,10 +890,10 @@ if(EXECUTORCH_BUILD_PYBIND)
   target_compile_options(portable_lib PUBLIC ${_pybind_compile_options})
   target_link_libraries(portable_lib PRIVATE ${_dep_libs})
 
-  # Set RPATH to find PyTorch libraries relative to the installation location
-  # This goes from executorch/extension/pybindings up to site-packages, then to
-  # torch/lib. Don't do this to APPLE, as it will error out on the following
-  # error:
+  # Set RPATH to find PyTorch and backend libraries relative to the installation
+  # location. This goes from executorch/extension/pybindings up to site-packages,
+  # then to torch/lib. If QNN is enabled, also add backends/qualcomm/.
+  # Don't do this to APPLE, as it will error out on the following error:
   #
   if(APPLE)
     # Skip setting @loader_path for APPLE, since it causes error like ld:
@@ -897,8 +901,8 @@ if(EXECUTORCH_BUILD_PYBIND)
     # libtorch_cpu.dylib'
   else()
     set_target_properties(
-      portable_lib PROPERTIES BUILD_RPATH "$ORIGIN/../../../torch/lib"
-                              INSTALL_RPATH "$ORIGIN/../../../torch/lib"
+      portable_lib PROPERTIES BUILD_RPATH "${_portable_lib_rpath}"
+                              INSTALL_RPATH "${_portable_lib_rpath}"
     )
   endif()
 
diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index 24ed1ed404d..7813d79171a 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -24,36 +24,44 @@ get_filename_component(
 )
 
 if(EXECUTORCH_BUILD_PYBIND)
-  find_package(
-    Python3
-    COMPONENTS Interpreter
-    REQUIRED
-  )
-  message(STATUS "QNN_SDK_ROOT not provided, downloading Qualcomm SDK")
-  execute_process(
-    COMMAND
-      ${Python3_EXECUTABLE}
-      ${EXECUTORCH_SOURCE_DIR}/backends/qualcomm/scripts/download_qnn_sdk.py
-      --print-sdk-path
-    WORKING_DIRECTORY ${EXECUTORCH_SOURCE_DIR}
-    RESULT_VARIABLE _qnn_sdk_download_result
-    OUTPUT_VARIABLE _qnn_sdk_download_output
-    ERROR_VARIABLE _qnn_sdk_download_error
-    OUTPUT_STRIP_TRAILING_WHITESPACE
-  )
-  if(NOT _qnn_sdk_download_result EQUAL 0 OR _qnn_sdk_download_output STREQUAL
-                                             ""
+  set(_qnn_default_sdk_dir "${CMAKE_CURRENT_BINARY_DIR}/sdk/qnn")
+
+  if(EXISTS "${_qnn_default_sdk_dir}" AND EXISTS
+                                          "${_qnn_default_sdk_dir}/lib"
   )
-    message(
-      FATAL_ERROR
-        "Failed to download Qualcomm SDK. stdout: ${_qnn_sdk_download_output}\n"
-        "stderr: ${_qnn_sdk_download_error}"
+    message(STATUS "Found cached Qualcomm SDK at ${_qnn_default_sdk_dir}")
+    set(QNN_SDK_ROOT
+        ${_qnn_default_sdk_dir}
+        CACHE PATH "Qualcomm SDK root directory" FORCE
+    )
+  else()
+    message(STATUS "Downloading Qualcomm SDK")
+    execute_process(
+      COMMAND
+        ${Python3_EXECUTABLE}
+        ${EXECUTORCH_SOURCE_DIR}/backends/qualcomm/scripts/download_qnn_sdk.py
+        --dst-folder ${_qnn_default_sdk_dir}
+        --print-sdk-path
+      WORKING_DIRECTORY ${EXECUTORCH_SOURCE_DIR}
+      RESULT_VARIABLE _qnn_sdk_download_result
+      OUTPUT_VARIABLE _qnn_sdk_download_output
+      ERROR_VARIABLE _qnn_sdk_download_error
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    if(NOT _qnn_sdk_download_result EQUAL 0 OR _qnn_sdk_download_output STREQUAL
+                                              ""
+    )
+      message(
+        FATAL_ERROR
+          "Failed to download Qualcomm SDK. stdout: ${_qnn_sdk_download_output}\n"
+          "stderr: ${_qnn_sdk_download_error}"
+      )
+    endif()
+    set(QNN_SDK_ROOT
+        ${_qnn_sdk_download_output}
+        CACHE PATH "Qualcomm SDK root directory" FORCE
     )
   endif()
-  set(QNN_SDK_ROOT
-      ${_qnn_sdk_download_output}
-      CACHE PATH "Qualcomm SDK root directory" FORCE
-  )
   set(ENV{QNN_SDK_ROOT} ${QNN_SDK_ROOT})
 endif()
 

From 5c971c0969e3c64c648aff4aa6448b167c93f5f1 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Tue, 4 Nov 2025 16:25:09 -0800
Subject: [PATCH 05/14] Test

---
 CMakeLists.txt | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cd6a16b94b7..536c10e8b59 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -891,9 +891,10 @@ if(EXECUTORCH_BUILD_PYBIND)
   target_link_libraries(portable_lib PRIVATE ${_dep_libs})
 
   # Set RPATH to find PyTorch and backend libraries relative to the installation
-  # location. This goes from executorch/extension/pybindings up to site-packages,
-  # then to torch/lib. If QNN is enabled, also add backends/qualcomm/.
-  # Don't do this to APPLE, as it will error out on the following error:
+  # location. This goes from executorch/extension/pybindings up to
+  # site-packages, then to torch/lib. If QNN is enabled, also add
+  # backends/qualcomm/. Don't do this to APPLE, as it will error out on the
+  # following error:
   #
   if(APPLE)
     # Skip setting @loader_path for APPLE, since it causes error like ld:

From 216f9a7c7676c2d69a95e23ba904ca6c87ae80ea Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Tue, 4 Nov 2025 21:01:02 -0800
Subject: [PATCH 06/14] Retry

---
 backends/qualcomm/CMakeLists.txt | 34 ++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index 7813d79171a..36c848cb2e2 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -34,6 +34,7 @@ if(EXECUTORCH_BUILD_PYBIND)
         ${_qnn_default_sdk_dir}
         CACHE PATH "Qualcomm SDK root directory" FORCE
     )
+<<<<<<< HEAD
   else()
     message(STATUS "Downloading Qualcomm SDK")
     execute_process(
@@ -55,6 +56,39 @@ if(EXECUTORCH_BUILD_PYBIND)
         FATAL_ERROR
           "Failed to download Qualcomm SDK. stdout: ${_qnn_sdk_download_output}\n"
           "stderr: ${_qnn_sdk_download_error}"
+=======
+      message(STATUS "Found cached Qualcomm SDK at ${_qnn_default_sdk_dir}")
+      set(QNN_SDK_ROOT
+          ${_qnn_default_sdk_dir}
+          CACHE PATH "Qualcomm SDK root directory" FORCE
+      )
+    else()
+      message(STATUS "QNN_SDK_ROOT not provided, downloading Qualcomm SDK")
+      execute_process(
+        COMMAND
+          ${PYTHON_EXECUTABLE}
+          ${EXECUTORCH_SOURCE_DIR}/backends/qualcomm/scripts/download_qnn_sdk.py
+          --dst-folder ${_qnn_default_sdk_dir}
+          --print-sdk-path
+        WORKING_DIRECTORY ${EXECUTORCH_SOURCE_DIR}
+        RESULT_VARIABLE _qnn_sdk_download_result
+        OUTPUT_VARIABLE _qnn_sdk_download_output
+        ERROR_VARIABLE _qnn_sdk_download_error
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+      )
+      if(NOT _qnn_sdk_download_result EQUAL 0 OR _qnn_sdk_download_output
+                                                 STREQUAL ""
+      )
+        message(
+          FATAL_ERROR
+            "Failed to download Qualcomm SDK. stdout: ${_qnn_sdk_download_output}\n"
+            "stderr: ${_qnn_sdk_download_error}"
+        )
+      endif()
+      set(QNN_SDK_ROOT
+          ${_qnn_sdk_download_output}
+          CACHE PATH "Qualcomm SDK root directory" FORCE
+>>>>>>> e13507fb51 (Retry)
       )
     endif()
     set(QNN_SDK_ROOT

From 106c3c738e24265fc8922fd378fad8a38a720838 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Tue, 4 Nov 2025 21:28:49 -0800
Subject: [PATCH 07/14] Turn off QNN in cuda.yml

---
 .github/workflows/cuda.yml       |  6 +++---
 backends/qualcomm/CMakeLists.txt | 36 +-------------------------------
 2 files changed, 4 insertions(+), 38 deletions(-)

diff --git a/.github/workflows/cuda.yml b/.github/workflows/cuda.yml
index 7cc937fe6ca..0572adf0ba3 100644
--- a/.github/workflows/cuda.yml
+++ b/.github/workflows/cuda.yml
@@ -44,7 +44,7 @@ jobs:
 
         # Test ExecuTorch CUDA build - ExecuTorch will automatically detect CUDA version
         # and install the appropriate PyTorch wheel
-        source .ci/scripts/test-cuda-build.sh "${{ matrix.cuda-version }}"
+        CMAKE_ARGS="-DEXECUTORCH_BUILD_QNN=OFF" source .ci/scripts/test-cuda-build.sh "${{ matrix.cuda-version }}"
 
   # This job will fail if any of the CUDA versions fail
   check-all-cuda-builds:
@@ -83,7 +83,7 @@ jobs:
       script: |
         set -eux
 
-        PYTHON_EXECUTABLE=python ./install_executorch.sh
+        CMAKE_ARGS="-DEXECUTORCH_BUILD_QNN=OFF" PYTHON_EXECUTABLE=python ./install_executorch.sh
         export LD_LIBRARY_PATH=/opt/conda/lib:$LD_LIBRARY_PATH
         PYTHON_EXECUTABLE=python source .ci/scripts/test_model.sh "${{ matrix.model }}" cmake cuda
 
@@ -132,7 +132,7 @@ jobs:
         set -eux
 
         echo "::group::Setup ExecuTorch"
-        ./install_executorch.sh
+        CMAKE_ARGS="-DEXECUTORCH_BUILD_QNN=OFF" ./install_executorch.sh
         echo "::endgroup::"
 
         echo "::group::Setup Huggingface"
diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index 36c848cb2e2..6dd59b7afbb 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -34,12 +34,11 @@ if(EXECUTORCH_BUILD_PYBIND)
         ${_qnn_default_sdk_dir}
         CACHE PATH "Qualcomm SDK root directory" FORCE
     )
-<<<<<<< HEAD
   else()
     message(STATUS "Downloading Qualcomm SDK")
     execute_process(
       COMMAND
-        ${Python3_EXECUTABLE}
+        ${PYTHON_EXECUTABLE}
         ${EXECUTORCH_SOURCE_DIR}/backends/qualcomm/scripts/download_qnn_sdk.py
         --dst-folder ${_qnn_default_sdk_dir}
         --print-sdk-path
@@ -56,39 +55,6 @@ if(EXECUTORCH_BUILD_PYBIND)
         FATAL_ERROR
           "Failed to download Qualcomm SDK. stdout: ${_qnn_sdk_download_output}\n"
           "stderr: ${_qnn_sdk_download_error}"
-=======
-      message(STATUS "Found cached Qualcomm SDK at ${_qnn_default_sdk_dir}")
-      set(QNN_SDK_ROOT
-          ${_qnn_default_sdk_dir}
-          CACHE PATH "Qualcomm SDK root directory" FORCE
-      )
-    else()
-      message(STATUS "QNN_SDK_ROOT not provided, downloading Qualcomm SDK")
-      execute_process(
-        COMMAND
-          ${PYTHON_EXECUTABLE}
-          ${EXECUTORCH_SOURCE_DIR}/backends/qualcomm/scripts/download_qnn_sdk.py
-          --dst-folder ${_qnn_default_sdk_dir}
-          --print-sdk-path
-        WORKING_DIRECTORY ${EXECUTORCH_SOURCE_DIR}
-        RESULT_VARIABLE _qnn_sdk_download_result
-        OUTPUT_VARIABLE _qnn_sdk_download_output
-        ERROR_VARIABLE _qnn_sdk_download_error
-        OUTPUT_STRIP_TRAILING_WHITESPACE
-      )
-      if(NOT _qnn_sdk_download_result EQUAL 0 OR _qnn_sdk_download_output
-                                                 STREQUAL ""
-      )
-        message(
-          FATAL_ERROR
-            "Failed to download Qualcomm SDK. stdout: ${_qnn_sdk_download_output}\n"
-            "stderr: ${_qnn_sdk_download_error}"
-        )
-      endif()
-      set(QNN_SDK_ROOT
-          ${_qnn_sdk_download_output}
-          CACHE PATH "Qualcomm SDK root directory" FORCE
->>>>>>> e13507fb51 (Retry)
       )
     endif()
     set(QNN_SDK_ROOT

From 8c829efa137a345d3a59f6324a0cbea9bc15964f Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Wed, 12 Nov 2025 14:54:55 -0800
Subject: [PATCH 08/14] Cleanup

---
 .github/workflows/cuda.yml       | 6 +++---
 backends/qualcomm/CMakeLists.txt | 1 +
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/cuda.yml b/.github/workflows/cuda.yml
index 0572adf0ba3..7cc937fe6ca 100644
--- a/.github/workflows/cuda.yml
+++ b/.github/workflows/cuda.yml
@@ -44,7 +44,7 @@ jobs:
 
         # Test ExecuTorch CUDA build - ExecuTorch will automatically detect CUDA version
         # and install the appropriate PyTorch wheel
-        CMAKE_ARGS="-DEXECUTORCH_BUILD_QNN=OFF" source .ci/scripts/test-cuda-build.sh "${{ matrix.cuda-version }}"
+        source .ci/scripts/test-cuda-build.sh "${{ matrix.cuda-version }}"
 
   # This job will fail if any of the CUDA versions fail
   check-all-cuda-builds:
@@ -83,7 +83,7 @@ jobs:
       script: |
         set -eux
 
-        CMAKE_ARGS="-DEXECUTORCH_BUILD_QNN=OFF" PYTHON_EXECUTABLE=python ./install_executorch.sh
+        PYTHON_EXECUTABLE=python ./install_executorch.sh
         export LD_LIBRARY_PATH=/opt/conda/lib:$LD_LIBRARY_PATH
         PYTHON_EXECUTABLE=python source .ci/scripts/test_model.sh "${{ matrix.model }}" cmake cuda
 
@@ -132,7 +132,7 @@ jobs:
         set -eux
 
         echo "::group::Setup ExecuTorch"
-        CMAKE_ARGS="-DEXECUTORCH_BUILD_QNN=OFF" ./install_executorch.sh
+        ./install_executorch.sh
         echo "::endgroup::"
 
         echo "::group::Setup Huggingface"
diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index 6dd59b7afbb..68be407d50c 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -23,6 +23,7 @@ get_filename_component(
   _common_include_directories "${EXECUTORCH_SOURCE_DIR}/.." ABSOLUTE
 )
 
+# We only download QNN SDK when we build pip wheel for ExecuTorch.
 if(EXECUTORCH_BUILD_PYBIND)
   set(_qnn_default_sdk_dir "${CMAKE_CURRENT_BINARY_DIR}/sdk/qnn")
 

From cc05d3b9180c9be8bf0fcac78e2eeb73d2b2d605 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Wed, 12 Nov 2025 15:02:28 -0800
Subject: [PATCH 09/14] Fix

---
 backends/qualcomm/CMakeLists.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index 68be407d50c..e0a90b59da5 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -64,6 +64,13 @@ if(EXECUTORCH_BUILD_PYBIND)
     )
   endif()
   set(ENV{QNN_SDK_ROOT} ${QNN_SDK_ROOT})
+elseif(NOT DEFINED QNN_SDK_ROOT)
+  message(
+    FATAL_ERROR
+      "Please define QNN_SDK_ROOT, e.g. cmake <..> -DQNN_SDK_ROOT=<...>"
+  )
+elseif(CMAKE_TOOLCHAIN_FILE MATCHES ".*(iOS|ios\.toolchain)\.cmake$")
+  message(FATAL_ERROR "ios is not supported by Qualcomm AI Engine Direct")
 endif()
 
 message(STATUS "Using qnn sdk root ${QNN_SDK_ROOT}")

From 4a65e0145323f6d5c9629b83a54ed4738617768e Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Wed, 12 Nov 2025 22:12:53 -0800
Subject: [PATCH 10/14] Address comments

---
 backends/qualcomm/CMakeLists.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index e0a90b59da5..bc31a6e3f2b 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -64,7 +64,9 @@ if(EXECUTORCH_BUILD_PYBIND)
     )
   endif()
   set(ENV{QNN_SDK_ROOT} ${QNN_SDK_ROOT})
-elseif(NOT DEFINED QNN_SDK_ROOT)
+endif()
+
+if(NOT DEFINED QNN_SDK_ROOT)
   message(
     FATAL_ERROR
       "Please define QNN_SDK_ROOT, e.g. cmake <..> -DQNN_SDK_ROOT=<...>"

From 5a6dc243bfc3721324df185f4dc3553d65221523 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Wed, 12 Nov 2025 22:13:53 -0800
Subject: [PATCH 11/14] Lint

---
 backends/qualcomm/CMakeLists.txt | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index bc31a6e3f2b..a6abf4d1638 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -27,9 +27,7 @@ get_filename_component(
 if(EXECUTORCH_BUILD_PYBIND)
   set(_qnn_default_sdk_dir "${CMAKE_CURRENT_BINARY_DIR}/sdk/qnn")
 
-  if(EXISTS "${_qnn_default_sdk_dir}" AND EXISTS
-                                          "${_qnn_default_sdk_dir}/lib"
-  )
+  if(EXISTS "${_qnn_default_sdk_dir}" AND EXISTS "${_qnn_default_sdk_dir}/lib")
     message(STATUS "Found cached Qualcomm SDK at ${_qnn_default_sdk_dir}")
     set(QNN_SDK_ROOT
         ${_qnn_default_sdk_dir}
@@ -41,16 +39,15 @@ if(EXECUTORCH_BUILD_PYBIND)
       COMMAND
         ${PYTHON_EXECUTABLE}
         ${EXECUTORCH_SOURCE_DIR}/backends/qualcomm/scripts/download_qnn_sdk.py
-        --dst-folder ${_qnn_default_sdk_dir}
-        --print-sdk-path
+        --dst-folder ${_qnn_default_sdk_dir} --print-sdk-path
       WORKING_DIRECTORY ${EXECUTORCH_SOURCE_DIR}
       RESULT_VARIABLE _qnn_sdk_download_result
       OUTPUT_VARIABLE _qnn_sdk_download_output
       ERROR_VARIABLE _qnn_sdk_download_error
       OUTPUT_STRIP_TRAILING_WHITESPACE
     )
-    if(NOT _qnn_sdk_download_result EQUAL 0 OR _qnn_sdk_download_output STREQUAL
-                                              ""
+    if(NOT _qnn_sdk_download_result EQUAL 0 OR _qnn_sdk_download_output
+                                               STREQUAL ""
     )
       message(
         FATAL_ERROR

From 16932190fe917a21f3f24c5d07f4e0becb56a5a1 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Wed, 12 Nov 2025 22:21:39 -0800
Subject: [PATCH 12/14] Address more comments

---
 backends/qualcomm/CMakeLists.txt | 2 +-
 setup.py                         | 2 ++
 tools/cmake/preset/default.cmake | 6 ++++++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index a6abf4d1638..5401e1929ed 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -24,7 +24,7 @@ get_filename_component(
 )
 
 # We only download QNN SDK when we build pip wheel for ExecuTorch.
-if(EXECUTORCH_BUILD_PYBIND)
+if(EXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY)
   set(_qnn_default_sdk_dir "${CMAKE_CURRENT_BINARY_DIR}/sdk/qnn")
 
   if(EXISTS "${_qnn_default_sdk_dir}" AND EXISTS "${_qnn_default_sdk_dir}/lib")
diff --git a/setup.py b/setup.py
index 71aa4c543d4..29214a9be2d 100644
--- a/setup.py
+++ b/setup.py
@@ -676,6 +676,8 @@ def run(self):  # noqa C901
             # like `TorchConfig.cmake` that are provided by pip packages.
             f"-DCMAKE_PREFIX_PATH={cmake_prefix_path}",
             f"-DCMAKE_BUILD_TYPE={cmake_build_type}",
+            # Turn on the wheel building option for downstream CMakeLists.txt.
+            f"-DEXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY=ON",
         ]
 
         # Use ClangCL on Windows.
diff --git a/tools/cmake/preset/default.cmake b/tools/cmake/preset/default.cmake
index 0dcec0df531..f0bbb0529ae 100644
--- a/tools/cmake/preset/default.cmake
+++ b/tools/cmake/preset/default.cmake
@@ -288,6 +288,12 @@ define_overridable_option(
   BOOL
   FALSE
 )
+define_overridable_option(
+  EXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY
+  "On if in the wheel building process. Should only be used to guard code that is only needed for building the wheel."
+  BOOL
+  FALSE
+)
 
 # ------------------------------------------------------------------------------
 # Validations

From 137052eab7454cf7fae95692d002e8992a10d256 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Thu, 13 Nov 2025 12:04:17 -0800
Subject: [PATCH 13/14] Address more comments

---
 backends/qualcomm/CMakeLists.txt | 3 ++-
 setup.py                         | 2 --
 tools/cmake/preset/default.cmake | 2 +-
 tools/cmake/preset/pybind.cmake  | 1 +
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index 5401e1929ed..48ea2fc35d9 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -24,7 +24,8 @@ get_filename_component(
 )
 
 # We only download QNN SDK when we build pip wheel for ExecuTorch.
-if(EXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY)
+# Please don't change this code unless you know what you are doing.
+if(EXECUTORCH_BUILD_WHEEL_DO_NOT_USE)
   set(_qnn_default_sdk_dir "${CMAKE_CURRENT_BINARY_DIR}/sdk/qnn")
 
   if(EXISTS "${_qnn_default_sdk_dir}" AND EXISTS "${_qnn_default_sdk_dir}/lib")
diff --git a/setup.py b/setup.py
index 29214a9be2d..71aa4c543d4 100644
--- a/setup.py
+++ b/setup.py
@@ -676,8 +676,6 @@ def run(self):  # noqa C901
             # like `TorchConfig.cmake` that are provided by pip packages.
             f"-DCMAKE_PREFIX_PATH={cmake_prefix_path}",
             f"-DCMAKE_BUILD_TYPE={cmake_build_type}",
-            # Turn on the wheel building option for downstream CMakeLists.txt.
-            f"-DEXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY=ON",
         ]
 
         # Use ClangCL on Windows.
diff --git a/tools/cmake/preset/default.cmake b/tools/cmake/preset/default.cmake
index f0bbb0529ae..1d12924bfa4 100644
--- a/tools/cmake/preset/default.cmake
+++ b/tools/cmake/preset/default.cmake
@@ -289,7 +289,7 @@ define_overridable_option(
   FALSE
 )
 define_overridable_option(
-  EXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY
+  EXECUTORCH_BUILD_WHEEL_DO_NOT_USE
   "On if in the wheel building process. Should only be used to guard code that is only needed for building the wheel."
   BOOL
   FALSE
diff --git a/tools/cmake/preset/pybind.cmake b/tools/cmake/preset/pybind.cmake
index 7c4de793721..a0d06d74d17 100644
--- a/tools/cmake/preset/pybind.cmake
+++ b/tools/cmake/preset/pybind.cmake
@@ -22,6 +22,7 @@ set_overridable_option(EXECUTORCH_BUILD_EXTENSION_FLAT_TENSOR ON)
 set_overridable_option(EXECUTORCH_BUILD_EXTENSION_DATA_LOADER ON)
 set_overridable_option(EXECUTORCH_BUILD_EXTENSION_MODULE ON)
 set_overridable_option(EXECUTORCH_BUILD_EXTENSION_NAMED_DATA_MAP ON)
+set_overridable_option(EXECUTORCH_BUILD_WHEEL_DO_NOT_USE ON)
 
 # TODO(larryliu0820): Temporarily disable building llm_runner for Windows wheel
 # due to the issue of tokenizer file path length limitation.

From 1acb1519c50f28289c6f404017485071366dd586 Mon Sep 17 00:00:00 2001
From: Mengwei Liu <larryliu@meta.com>
Date: Mon, 17 Nov 2025 11:23:53 -0800
Subject: [PATCH 14/14] Lint

---
 backends/qualcomm/CMakeLists.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/backends/qualcomm/CMakeLists.txt b/backends/qualcomm/CMakeLists.txt
index 48ea2fc35d9..cc7957dfdbe 100644
--- a/backends/qualcomm/CMakeLists.txt
+++ b/backends/qualcomm/CMakeLists.txt
@@ -23,8 +23,8 @@ get_filename_component(
   _common_include_directories "${EXECUTORCH_SOURCE_DIR}/.." ABSOLUTE
 )
 
-# We only download QNN SDK when we build pip wheel for ExecuTorch.
-# Please don't change this code unless you know what you are doing.
+# We only download QNN SDK when we build pip wheel for ExecuTorch. Please don't
+# change this code unless you know what you are doing.
 if(EXECUTORCH_BUILD_WHEEL_DO_NOT_USE)
   set(_qnn_default_sdk_dir "${CMAKE_CURRENT_BINARY_DIR}/sdk/qnn")