MLECO-1860: Support for Arm GNU Embedded Toolchain

This patch enables compilation of ML use cases bare-metal applications
using Arm GNU Embedded Toolchain. The GNU toolchain can be used instead
of the Arm Compiler that was already supported.

The GNU toolchain is also set as the default toolchain when building
applications for the MPS3 target.

Note: The version of GNU toolchain must be 10.2.1 or higher.

Change-Id: I5fff242f0f52d2db6c75d292f9fa990df1aec978
Signed-off-by: Kshitij Sisodia <kshitij.sisodia@arm.com>
diff --git a/build_default.py b/build_default.py
index 318ccb1..b61da13 100644
--- a/build_default.py
+++ b/build_default.py
@@ -26,12 +26,13 @@
 from set_up_default_resources import set_up_resources
 
 
-def run(download_resources, run_vela_on_models):
+def run(toolchain: str, download_resources: bool, run_vela_on_models: bool):
     """
     Run the helpers scripts.
 
     Parameters:
     ----------
+    toolchain (str)          :    Specifies if 'gnu' or 'arm' toolchain needs to be used.
     download_resources (bool):    Specifies if 'Download resources' step is performed.
     run_vela_on_models (bool):    Only if `download_resources` is True, specifies if run vela on downloaded models.
     """
@@ -40,16 +41,25 @@
     logging.basicConfig(filename='log_build_default.log', level=logging.DEBUG)
     logging.getLogger().addHandler(logging.StreamHandler(sys.stdout))
 
-    # 1. Download models if specified
+    # 1. Make sure the toolchain is supported, and set the right one here
+    supported_toolchain_ids = ["gnu", "arm"]
+    assert toolchain in supported_toolchain_ids, f"Toolchain must be from {supported_toolchain_ids}"
+    if toolchain == "arm":
+        toolchain_file_name = "bare-metal-armclang.cmake"
+    elif toolchain == "gnu":
+        toolchain_file_name = "bare-metal-gcc.cmake"
+
+    # 2. Download models if specified
     if download_resources is True:
         logging.info("Downloading resources.")
         set_up_resources(run_vela_on_models)
 
-    # 2. Build default configuration
+    # 3. Build default configuration
     logging.info("Building default configuration.")
     target_platform = "mps3"
     target_subsystem = "sse-300"
-    build_dir = os.path.join(current_file_dir, f"cmake-build-{target_platform}-{target_subsystem}-release")
+    build_dir = os.path.join(current_file_dir,
+        f"cmake-build-{target_platform}-{target_subsystem}-{toolchain}-release")
     try:
         os.mkdir(build_dir)
     except FileExistsError:
@@ -63,10 +73,14 @@
                     shutil.rmtree(filepath)
             except Exception as e:
                 logging.error('Failed to delete %s. Reason: %s' % (filepath, e))
+
     os.chdir(build_dir)
-    cmake_toolchain_file = os.path.join(current_file_dir, "scripts", "cmake", "bare-metal-toolchain.cmake")
-    cmake_command = (f"cmake .. -DTARGET_PLATFORM={target_platform} -DTARGET_SUBSYSTEM={target_subsystem} " +
-                     f"-DCMAKE_TOOLCHAIN_FILE={cmake_toolchain_file} ")
+    cmake_toolchain_file = os.path.join(current_file_dir, "scripts", "cmake",
+                                        "toolchains", toolchain_file_name)
+    cmake_command = (f"cmake .. -DTARGET_PLATFORM={target_platform} " +
+                     f"-DTARGET_SUBSYSTEM={target_subsystem} " +
+                     f" -DCMAKE_TOOLCHAIN_FILE={cmake_toolchain_file}")
+
     logging.info(cmake_command)
     state = subprocess.run(cmake_command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
     logging.info(state.stdout.decode('utf-8'))
@@ -79,6 +93,11 @@
 
 if __name__ == '__main__':
     parser = ArgumentParser()
+    parser.add_argument("--toolchain", default="gnu",
+                        help="""
+                        Specify the toolchain to use (Arm or GNU).
+                        Options are [gnu, arm]; default is gnu.
+                        """)
     parser.add_argument("--skip-download",
                         help="Do not download resources: models and test vectors",
                         action="store_true")
@@ -86,4 +105,4 @@
                         help="Do not run Vela optimizer on downloaded models.",
                         action="store_true")
     args = parser.parse_args()
-    run(not args.skip_download, not args.skip_vela)
+    run(args.toolchain.lower(), not args.skip_download, not args.skip_vela)