[UTC] Fix bounds safety default checks in update_cc_test_checks.py

Previously update_cc_test_checks.py would append the default bounds
check flag to the end of the RUN line. If the original RUN line
contained any bounds check flags they would be overridden by this. The
default bounds check flag is now inserted immediately after the
%clang_cc1 expansion, so that the RUN line can override it.

Author: hnrklssn

llvm/utils/update_cc_test_checks.py

@@ -358,11 +358,6 @@ def update_test(ti: common.TestInfo):
         # This is a clang runline, apply %clang substitution rule, do lit-like substitutions,
         # and append args.clang_args
         clang_args = exec_args
-        # DO_NOT_UPSTREAM(BoundsSafety) ON
-        original_subst = clang_args[0] # Apple Internal
-        # DO_NOT_UPSTREAM(BoundsSafety) OFF
-        clang_args[0:1] = SUBST[clang_args[0]]
-
         # DO_NOT_UPSTREAM(BoundsSafety) ON
         # The -fbounds-safety tests under:
         #
@@ -377,16 +372,17 @@ def update_test(ti: common.TestInfo):
         #
         # This can be removed once support for the legacy bounds checks are
         # removed (rdar://134095901)
+        original_subst = clang_args[0] # Apple Internal
         if is_bounds_safety_test_with_new_bounds_checks(ti) and original_subst == "%clang_cc1":
-            enable_bounds_safety_checks_flag = '-fbounds-safety-bringup-missing-checks=batch_0'
-            print(f"Implicitly adding {enable_bounds_safety_checks_flag}")
-            clang_args.append(enable_bounds_safety_checks_flag)
-
-        if is_bounds_safety_test_with_legacy_bounds_checks(ti) and original_subst == "%clang_cc1":
-            enable_bounds_safety_legacy_checks_flag = '-fno-bounds-safety-bringup-missing-checks=all'
-            print(f"Implicitly adding {enable_bounds_safety_legacy_checks_flag}")
-            clang_args.append(enable_bounds_safety_legacy_checks_flag)
+            default_bounds_safety_checks_flag = ['-fbounds-safety-bringup-missing-checks=batch_0']
+            print(f"Implicitly adding {default_bounds_safety_checks_flag[0]}")
+        elif is_bounds_safety_test_with_legacy_bounds_checks(ti) and original_subst == "%clang_cc1":
+            default_bounds_safety_checks_flag = ['-fno-bounds-safety-bringup-missing-checks=all']
+            print(f"Implicitly adding {default_bounds_safety_checks_flag[0]}")
+        else:
+            default_bounds_safety_checks_flag = []
         # DO_NOT_UPSTREAM(BoundsSafety) OFF
+        clang_args[0:1] = SUBST[clang_args[0]] + default_bounds_safety_checks_flag
 
         for s in subs:
             clang_args = [i.replace(s, subs[s]) if s in i else i for i in clang_args]