Issue #25188: Add a -P/--pgo flag to regrtest to silence error output.

Since PGO building doesn't care about test failures, silence them when
running the test suite for performance reasons. Initial patch by
Alecsandru Patrascu of Intel.

Lib/test/regrtest.py

@@ -322,6 +322,8 @@ def _create_parser():
     group.add_argument('-F', '--forever', action='store_true',
                        help='run the specified tests in a loop, until an '
                             'error happens')
+    group.add_argument('-P', '--pgo', dest='pgo', action='store_true',
+                       help='enable Profile Guided Optimization training')
 
     parser.add_argument('args', nargs=argparse.REMAINDER,
                         help=argparse.SUPPRESS)
@@ -361,7 +363,7 @@ def _parse_args(args, **kwargs):
          findleaks=False, use_resources=None, trace=False, coverdir='coverage',
          runleaks=False, huntrleaks=False, verbose2=False, print_slow=False,
          random_seed=None, use_mp=None, verbose3=False, forever=False,
-         header=False, failfast=False, match_tests=None)
+         header=False, failfast=False, match_tests=None, pgo=False)
     for k, v in kwargs.items():
         if not hasattr(ns, k):
             raise TypeError('%r is an invalid keyword argument '
@@ -435,14 +437,16 @@ def run_test_in_subprocess(testname, ns):
     from subprocess import Popen, PIPE
     base_cmd = ([sys.executable] + support.args_from_interpreter_flags() +
                 ['-X', 'faulthandler', '-m', 'test.regrtest'])
-
+    # required to spawn a new process with PGO flag on/off
+    if ns.pgo:
+        base_cmd = base_cmd + ['--pgo']
     slaveargs = (
             (testname, ns.verbose, ns.quiet),
             dict(huntrleaks=ns.huntrleaks,
                  use_resources=ns.use_resources,
                  output_on_failure=ns.verbose3,
                  timeout=ns.timeout, failfast=ns.failfast,
-                 match_tests=ns.match_tests))
+                 match_tests=ns.match_tests, pgo=ns.pgo))
     # Running the child from the same working directory as regrtest's original
     # invocation ensures that TEMPDIR for the child is the same when
     # sysconfig.is_python_build() is true. See issue 15300.
@@ -596,13 +600,14 @@ def main(tests=None, **kwargs):
         ns.args = []
 
     # For a partial run, we do not need to clutter the output.
-    if ns.verbose or ns.header or not (ns.quiet or ns.single or tests or ns.args):
+    if (ns.verbose or ns.header or
+            not (ns.pgo or ns.quiet or ns.single or tests or ns.args)):
         # Print basic platform information
         print("==", platform.python_implementation(), *sys.version.split())
         print("==  ", platform.platform(aliased=True),
-                      "%s-endian" % sys.byteorder)
+                        "%s-endian" % sys.byteorder)
         print("==  ", "hash algorithm:", sys.hash_info.algorithm,
-              "64bit" if sys.maxsize > 2**32 else "32bit")
+                "64bit" if sys.maxsize > 2**32 else "32bit")
         print("==  ", os.getcwd())
         print("Testing with flags:", sys.flags)
 
@@ -722,13 +727,16 @@ def main(tests=None, **kwargs):
                     continue
                 accumulate_result(test, result)
                 if not ns.quiet:
-                    fmt = "[{1:{0}}{2}/{3}] {4}" if bad else "[{1:{0}}{2}] {4}"
+                    if bad and not ns.pgo:
+                        fmt = "[{1:{0}}{2}/{3}] {4}"
+                    else:
+                        fmt = "[{1:{0}}{2}] {4}"
                     print(fmt.format(
                         test_count_width, test_index, test_count,
                         len(bad), test))
                 if stdout:
                     print(stdout)
-                if stderr:
+                if stderr and not ns.pgo:
                     print(stderr, file=sys.stderr)
                 sys.stdout.flush()
                 sys.stderr.flush()
@@ -745,7 +753,10 @@ def main(tests=None, **kwargs):
     else:
         for test_index, test in enumerate(tests, 1):
             if not ns.quiet:
-                fmt = "[{1:{0}}{2}/{3}] {4}" if bad else "[{1:{0}}{2}] {4}"
+                if bad and not ns.pgo:
+                    fmt = "[{1:{0}}{2}/{3}] {4}"
+                else:
+                    fmt = "[{1:{0}}{2}] {4}"
                 print(fmt.format(
                     test_count_width, test_index, test_count, len(bad), test))
                 sys.stdout.flush()
@@ -760,7 +771,7 @@ def main(tests=None, **kwargs):
                                      ns.huntrleaks,
                                      output_on_failure=ns.verbose3,
                                      timeout=ns.timeout, failfast=ns.failfast,
-                                     match_tests=ns.match_tests)
+                                     match_tests=ns.match_tests, pgo=ns.pgo)
                     accumulate_result(test, result)
                 except KeyboardInterrupt:
                     interrupted = True
@@ -779,14 +790,14 @@ def main(tests=None, **kwargs):
                 if module not in save_modules and module.startswith("test."):
                     support.unload(module)
 
-    if interrupted:
+    if interrupted and not ns.pgo:
         # print a newline after ^C
         print()
         print("Test suite interrupted by signal SIGINT.")
         omitted = set(selected) - set(good) - set(bad) - set(skipped)
         print(count(len(omitted), "test"), "omitted:")
         printlist(omitted)
-    if good and not ns.quiet:
+    if good and not ns.quiet and not ns.pgo:
         if not bad and not skipped and not interrupted and len(good) > 1:
             print("All", end=' ')
         print(count(len(good), "test"), "OK.")
@@ -795,26 +806,27 @@ def main(tests=None, **kwargs):
         print("10 slowest tests:")
         for time, test in test_times[:10]:
             print("%s: %.1fs" % (test, time))
-    if bad:
+    if bad and not ns.pgo:
         print(count(len(bad), "test"), "failed:")
         printlist(bad)
-    if environment_changed:
+    if environment_changed and not ns.pgo:
         print("{} altered the execution environment:".format(
                  count(len(environment_changed), "test")))
         printlist(environment_changed)
-    if skipped and not ns.quiet:
+    if skipped and not ns.quiet and not ns.pgo:
         print(count(len(skipped), "test"), "skipped:")
         printlist(skipped)
 
     if ns.verbose2 and bad:
         print("Re-running failed tests in verbose mode")
         for test in bad[:]:
-            print("Re-running test %r in verbose mode" % test)
+            if not ns.pgo:
+                print("Re-running test %r in verbose mode" % test)
             sys.stdout.flush()
             try:
                 ns.verbose = True
                 ok = runtest(test, True, ns.quiet, ns.huntrleaks,
-                             timeout=ns.timeout)
+                             timeout=ns.timeout, pgo=ns.pgo)
             except KeyboardInterrupt:
                 # print a newline separate from the ^C
                 print()
@@ -913,7 +925,7 @@ def replace_stdout():
 def runtest(test, verbose, quiet,
             huntrleaks=False, use_resources=None,
             output_on_failure=False, failfast=False, match_tests=None,
-            timeout=None):
+            timeout=None, *, pgo=False):
     """Run a single test.
 
     test -- the name of the test
@@ -926,6 +938,8 @@ def runtest(test, verbose, quiet,
     timeout -- dump the traceback and exit if a test takes more than
                timeout seconds
     failfast, match_tests -- See regrtest command-line flags for these.
+    pgo -- if true, do not print unnecessary info when running the test
+           for Profile Guided Optimization build
 
     Returns the tuple result, test_time, where result is one of the constants:
         INTERRUPTED      KeyboardInterrupt when run under -j
@@ -935,7 +949,6 @@ def runtest(test, verbose, quiet,
         FAILED           test failed
         PASSED           test passed
     """
-
     if use_resources is not None:
         support.use_resources = use_resources
     use_timeout = (timeout is not None)
@@ -965,8 +978,8 @@ def runtest(test, verbose, quiet,
                 sys.stdout = stream
                 sys.stderr = stream
                 result = runtest_inner(test, verbose, quiet, huntrleaks,
-                                       display_failure=False)
-                if result[0] == FAILED:
+                                       display_failure=False, pgo=pgo)
+                if result[0] == FAILED and not pgo:
                     output = stream.getvalue()
                     orig_stderr.write(output)
                     orig_stderr.flush()
@@ -976,7 +989,7 @@ def runtest(test, verbose, quiet,
         else:
             support.verbose = verbose  # Tell tests to be moderately quiet
             result = runtest_inner(test, verbose, quiet, huntrleaks,
-                                   display_failure=not verbose)
+                                   display_failure=not verbose, pgo=pgo)
         return result
     finally:
         if use_timeout:
@@ -1008,10 +1021,11 @@ class saved_test_environment:
 
     changed = False
 
-    def __init__(self, testname, verbose=0, quiet=False):
+    def __init__(self, testname, verbose=0, quiet=False, *, pgo=False):
         self.testname = testname
         self.verbose = verbose
         self.quiet = quiet
+        self.pgo = pgo
 
     # To add things to save and restore, add a name XXX to the resources list
     # and add corresponding get_XXX/restore_XXX functions.  get_XXX should
@@ -1240,11 +1254,11 @@ class saved_test_environment:
             if current != original:
                 self.changed = True
                 restore(original)
-                if not self.quiet:
+                if not self.quiet and not self.pgo:
                     print("Warning -- {} was modified by {}".format(
                                                  name, self.testname),
                                                  file=sys.stderr)
-                    if self.verbose > 1:
+                    if self.verbose > 1 and not self.pgo:
                         print("  Before: {}\n  After:  {} ".format(
                                                   original, current),
                                                   file=sys.stderr)
@@ -1252,7 +1266,7 @@ class saved_test_environment:
 
 
 def runtest_inner(test, verbose, quiet,
-                  huntrleaks=False, display_failure=True):
+                  huntrleaks=False, display_failure=True, pgo=False):
     support.unload(test)
 
     test_time = 0.0
@@ -1263,7 +1277,7 @@ def runtest_inner(test, verbose, quiet,
         else:
             # Always import it from the test package
             abstest = 'test.' + test
-        with saved_test_environment(test, verbose, quiet) as environment:
+        with saved_test_environment(test, verbose, quiet, pgo=pgo) as environment:
             start_time = time.time()
             the_module = importlib.import_module(abstest)
             # If the test has a test_main, that will run the appropriate
@@ -1283,27 +1297,29 @@ def runtest_inner(test, verbose, quiet,
                 refleak = dash_R(the_module, test, test_runner, huntrleaks)
             test_time = time.time() - start_time
     except support.ResourceDenied as msg:
-        if not quiet:
+        if not quiet and not pgo:
             print(test, "skipped --", msg)
             sys.stdout.flush()
         return RESOURCE_DENIED, test_time
     except unittest.SkipTest as msg:
-        if not quiet:
+        if not quiet and not pgo:
             print(test, "skipped --", msg)
             sys.stdout.flush()
         return SKIPPED, test_time
     except KeyboardInterrupt:
         raise
     except support.TestFailed as msg:
-        if display_failure:
-            print("test", test, "failed --", msg, file=sys.stderr)
-        else:
-            print("test", test, "failed", file=sys.stderr)
+        if not pgo:
+            if display_failure:
+                print("test", test, "failed --", msg, file=sys.stderr)
+            else:
+                print("test", test, "failed", file=sys.stderr)
         sys.stderr.flush()
         return FAILED, test_time
     except:
         msg = traceback.format_exc()
-        print("test", test, "crashed --", msg, file=sys.stderr)
+        if not pgo:
+            print("test", test, "crashed --", msg, file=sys.stderr)
         sys.stderr.flush()
         return FAILED, test_time
     else:

Makefile.pre.in

@@ -231,7 +231,7 @@ TCLTK_INCLUDES=	@TCLTK_INCLUDES@
 TCLTK_LIBS=	@TCLTK_LIBS@
 
 # The task to run while instrument when building the profile-opt target
-PROFILE_TASK=-m test.regrtest >/dev/null 2>&1
+PROFILE_TASK=-m test.regrtest --pgo
 
 # report files for gcov / lcov coverage report
 COVERAGE_INFO=	$(abs_builddir)/coverage.info