Add some small benchmarks

tests/meson.build

@@ -1,5 +1,13 @@
 
-cases = [
+test_driver = executable('test_driver', 'driver.c',
+                         dependencies: libx86decode,
+                         c_args: ['-D_GNU_SOURCE'])
+test_args = [files('test.py'), test_driver, archmode]
+
+
+## Test cases
+
+testcases = [
   ['enter', 'decode-enter.sh'],
   ['imul', 'decode-imul.sh'],
   ['inc', 'decode-inc.sh'],
@@ -10,11 +18,19 @@ cases = [
   ['sse-movq', 'decode-sse-movq.sh'],
 ]
 
-test_driver = executable('test_driver', 'driver.c',
-                         dependencies: libx86decode,
-                         c_args: ['-D_GNU_SOURCE'])
-test_args = files('test.py') + [test_driver.full_path(), get_option('archmode')]
-
-foreach case : cases
+foreach case : testcases
   test(case[0], python3, args: test_args + files(case[1]))
 endforeach
+
+
+## Benchmarks
+#
+# Note that we don't use meson's benchmark function here, because it doesn't
+# give us the output we need by default.
+
+benchmarks = [
+  'benchmarks.txt',
+]
+
+run_target('benchmark_decode',
+           command: [python3, test_args, '--benchmark', files(benchmarks)])