test_benchmark.py: Make hardcode_arguments aware of args (#26293)

Previously we were just always embedding `DEFAULT_ARG`, but the caller
can pass whatever args they like.

Since `hardcode_arguments` is already best effort (it doesn't work
unless it can fine `int main` in the source code and when it cannot it
silently does nothing) it seems reasonable to also bail out in the same
way if we have more than one argument (which we do not support).

See #8081

Author: sbc100

test/test_benchmark.py

@@ -408,10 +408,19 @@ def tearDownClass(cls):
       }
       utils.write_file('stats.json', json.dumps(output, indent=2) + '\n')
 
-  # avoid depending on argument reception from the commandline
-  def hardcode_arguments(self, code):
+  def hardcode_arguments(self, code, args):
+    """Avoid depending on argument reception from the commandline, where possible.
+
+    Here we take the command line arguments and embed them directly into `main` function.
+    If we cannot find a `main` function, or if we have more than one argument, we
+    do not do any embedding, and the resulting test will depend on arguments being
+    passed via argv (which works in most environments).
+    """
     if not code or 'int main()' in code:
       return code
+    # We only know how to embed a single argument
+    if len(args) != 1:
+      return code
     main_pattern = 'int main(int argc, char **argv)'
     assert main_pattern in code
     code = code.replace(main_pattern, 'int benchmark_main(int argc, char **argv)')
@@ -422,7 +431,7 @@ def hardcode_arguments(self, code):
         int ret = benchmark_main(newArgc, newArgv);
         return ret;
       }
-    ''' % DEFAULT_ARG
+    ''' % args[0]
     return code
 
   def do_benchmark(self, name, src, expected_output='FAIL', args=None,
@@ -436,7 +445,7 @@ def do_benchmark(self, name, src, expected_output='FAIL', args=None,
     args = args or [DEFAULT_ARG]
     dirname = self.get_dir()
     filename = os.path.join(dirname, name + '.c' + ('' if force_c else 'pp'))
-    src = self.hardcode_arguments(src)
+    src = self.hardcode_arguments(src, args)
     utils.write_file(filename, src)
 
     print()