Make the API/ABI check optional

This way we can add other checks and only run a subset of all the
checks. The default remains to run all the checks.

I made separate options for API and ABI, but since we use the same
tool for both and it doesn't have an obvious way to check only API or
only ABI, the two options must be both enabled or both disabled.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/scripts/abi_check.py b/scripts/abi_check.py
index 3cfd95a..c8dad27 100755
--- a/scripts/abi_check.py
+++ b/scripts/abi_check.py
@@ -51,6 +51,8 @@
         configuration.report_dir: directory for output files
         configuration.keep_all_reports: if false, delete old reports
         configuration.brief: if true, output shorter report to stdout
+        configuration.check_api: if true, compare ABIs
+        configuration.check_api: if true, compare APIs
         configuration.skip_file: path to file containing symbols and types to skip
         """
         self.repo_path = "."
@@ -64,6 +66,10 @@
         self.old_version = old_version
         self.new_version = new_version
         self.skip_file = configuration.skip_file
+        self.check_abi = configuration.check_abi
+        self.check_api = configuration.check_api
+        if self.check_abi != self.check_api:
+            raise Exception('Checking API without ABI or vice versa is not supported')
         self.brief = configuration.brief
         self.git_command = "git"
         self.make_command = "make"
@@ -222,8 +228,9 @@
         """Generate the ABI dumps for the specified git revision."""
         git_worktree_path = self._get_clean_worktree_for_git_revision(version)
         self._update_git_submodules(git_worktree_path, version)
-        self._build_shared_libraries(git_worktree_path, version)
-        self._get_abi_dumps_from_shared_libraries(version)
+        if self.check_abi:
+            self._build_shared_libraries(git_worktree_path, version)
+            self._get_abi_dumps_from_shared_libraries(version)
         self._cleanup_worktree(git_worktree_path)
 
     def _remove_children_with_tag(self, parent, tag):
@@ -310,11 +317,14 @@
             self._pretty_revision(self.new_version)
         )]
         compliance_return_code = 0
-        shared_modules = list(set(self.old_version.modules.keys()) &
-                              set(self.new_version.modules.keys()))
-        for mbed_module in shared_modules:
-            if not self._is_library_compatible(mbed_module,
-                                               compatibility_report):
+        if self.check_abi:
+            shared_modules = list(set(self.old_version.modules.keys()) &
+                                  set(self.new_version.modules.keys()))
+            for mbed_module in shared_modules:
+                if not self._is_library_compatible(mbed_module,
+                                                   compatibility_report):
+                    compliance_return_code = 1
+
                 compliance_return_code = 1
         for version in [self.old_version, self.new_version]:
             for mbed_module, mbed_module_dump in version.abi_dumps.items():
@@ -398,6 +408,18 @@
                   "\"tests/scripts/list-identifiers.sh --internal\")")
         )
         parser.add_argument(
+            "--check-abi",
+            action='store_true', default=True,
+            help="Perform ABI comparison (default: yes)"
+        )
+        parser.add_argument("--no-check-abi", action='store_false', dest='check_abi')
+        parser.add_argument(
+            "--check-api",
+            action='store_true', default=True,
+            help="Perform API comparison (default: yes)"
+        )
+        parser.add_argument("--no-check-api", action='store_false', dest='check_api')
+        parser.add_argument(
             "-b", "--brief", action="store_true",
             help="output only the list of issues to stdout, instead of a full report",
         )
@@ -430,6 +452,8 @@
             report_dir=abi_args.report_dir,
             keep_all_reports=abi_args.keep_all_reports,
             brief=abi_args.brief,
+            check_abi=abi_args.check_abi,
+            check_api=abi_args.check_api,
             skip_file=abi_args.skip_file
         )
         abi_check = AbiChecker(old_version, new_version, configuration)