main/python3: reduce number of unit tests for PGO

Backport upstream patch that reduced number tests that are run for the
profile guided optimization. This reduced build time significantly and
fixes builders that hangs during build.

Problem was introduced with commit df3979dba3df (main/python3: enable
optimizations).

Upstream issue: https://bugs.python.org/issue36044

2 files changed, 237 insertions, 2 deletions

diff --git a/main/python3/APKBUILD b/main/python3/APKBUILD
index 8e4dcf5755b..1aadfa8a9b7 100644
--- a/main/python3/APKBUILD
+++ b/main/python3/APKBUILD
@@ -5,7 +5,7 @@ pkgname=python3
 # the python2-tkinter's pkgver needs to be synchronized with this.
 pkgver=3.7.5
 _basever="${pkgver%.*}"
-pkgrel=0
+pkgrel=1
 pkgdesc="A high-level scripting language"
 url="https://www.python.org"
 arch="all"
@@ -19,6 +19,7 @@ makedepends="expat-dev openssl-dev zlib-dev ncurses-dev bzip2-dev xz-dev
 source="https://www.python.org/ftp/python/$pkgver/Python-$pkgver.tar.xz
 	fix-xattrs-glibc.patch
 	musl-find_library.patch
+	bpo-36044-Reduce-number-of-unit-tests-run-for-PGO-build.patch
 	"
 builddir="$srcdir/Python-$pkgver"
 
@@ -162,4 +163,5 @@ wininst() {
 
 sha512sums="f4f3879881f260f58dbb041fb0f2f210d4b70b02a739e41e50e6fea67d31855a7a29ce4ebef66bfde3d0edf54b946a48f78490f986da965357b835d4dbb3f414  Python-3.7.5.tar.xz
 37b6ee5d0d5de43799316aa111423ba5a666c17dc7f81b04c330f59c1d1565540eac4c585abe2199bbed52ebe7426001edb1c53bd0a17486a2a8e052d0f494ad  fix-xattrs-glibc.patch
-ab8eaa2858d5109049b1f9f553198d40e0ef8d78211ad6455f7b491af525bffb16738fed60fc84e960c4889568d25753b9e4a1494834fea48291b33f07000ec2  musl-find_library.patch"
+ab8eaa2858d5109049b1f9f553198d40e0ef8d78211ad6455f7b491af525bffb16738fed60fc84e960c4889568d25753b9e4a1494834fea48291b33f07000ec2  musl-find_library.patch
+ad2715f2a4ddfed714f6040b79deed691f457e1e57c5d880c741ef71c5db5bad02a5faab50c32cd98e517ad1117ddf6d2fea0c3daf178d029e6a5fce2f95444a  bpo-36044-Reduce-number-of-unit-tests-run-for-PGO-build.patch"
diff --git a/main/python3/bpo-36044-Reduce-number-of-unit-tests-run-for-PGO-build.patch b/main/python3/bpo-36044-Reduce-number-of-unit-tests-run-for-PGO-build.patch
new file mode 100644
index 00000000000..b9b3ce35ceb
--- /dev/null
+++ b/main/python3/bpo-36044-Reduce-number-of-unit-tests-run-for-PGO-build.patch
@@ -0,0 +1,233 @@
+From 2406672984e4c1b18629e615edad52928a72ffcc Mon Sep 17 00:00:00 2001
+From: "Miss Islington (bot)"
+ <31488909+miss-islington@users.noreply.github.com>
+Date: Mon, 22 Jul 2019 13:17:23 -0700
+Subject: [PATCH] bpo-36044: Reduce number of unit tests run for PGO build
+ (GH-14702)
+
+Reduce the number of unit tests run for the PGO generation task.  This
+speeds up the task by a factor of about 15x.  Running the full unit test
+suite is slow.  This change may result in a slightly less optimized build
+since not as many code branches will be executed.  If you are willing to
+wait for the much slower build, the old behavior can be restored using
+'./configure [..] PROFILE_TASK="-m test --pgo-extended"'.  We make no
+guarantees as to which PGO task set produces a faster build.  Users who
+care should run their own relevant benchmarks as results can depend on
+the environment, workload, and compiler tool chain.
+(cherry picked from commit 4e16a4a3112161a5c6981c0588142d4a4673a934)
+
+Co-authored-by: Neil Schemenauer <nas-github@arctrix.com>
+---
+ Lib/test/libregrtest/cmdline.py               |  6 ++-
+ Lib/test/libregrtest/main.py                  |  4 ++
+ Lib/test/libregrtest/pgo.py                   | 52 +++++++++++++++++++
+ Makefile.pre.in                               |  7 +--
+ .../2019-07-11-01-28-24.bpo-36044.gIgfiJ.rst  |  9 ++++
+ configure                                     | 14 +++++
+ configure.ac                                  |  8 +++
+ 7 files changed, 96 insertions(+), 4 deletions(-)
+ create mode 100644 Lib/test/libregrtest/pgo.py
+ create mode 100644 Misc/NEWS.d/next/Build/2019-07-11-01-28-24.bpo-36044.gIgfiJ.rst
+
+diff --git a/Lib/test/libregrtest/cmdline.py b/Lib/test/libregrtest/cmdline.py
+index 9f1bf6800824a..c8fedc7ad329b 100644
+--- a/Lib/test/libregrtest/cmdline.py
++++ b/Lib/test/libregrtest/cmdline.py
+@@ -264,7 +264,9 @@ def _create_parser():
+                        help='only write the name of test cases that will be run'
+                             ' , don\'t execute them')
+     group.add_argument('-P', '--pgo', dest='pgo', action='store_true',
+-                       help='enable Profile Guided Optimization training')
++                       help='enable Profile Guided Optimization (PGO) training')
++    group.add_argument('--pgo-extended', action='store_true',
++                       help='enable extended PGO training (slower training)')
+     group.add_argument('--fail-env-changed', action='store_true',
+                        help='if a test file alters the environment, mark '
+                             'the test as failed')
+@@ -344,6 +346,8 @@ def _parse_args(args, **kwargs):
+         parser.error("-G/--failfast needs either -v or -W")
+     if ns.pgo and (ns.verbose or ns.verbose2 or ns.verbose3):
+         parser.error("--pgo/-v don't go together!")
++    if ns.pgo_extended:
++        ns.pgo = True  # pgo_extended implies pgo
+ 
+     if ns.nowindows:
+         print("Warning: the --nowindows (-n) option is deprecated. "
+diff --git a/Lib/test/libregrtest/main.py b/Lib/test/libregrtest/main.py
+index e2274254fdb89..78b6790685c9d 100644
+--- a/Lib/test/libregrtest/main.py
++++ b/Lib/test/libregrtest/main.py
+@@ -17,6 +17,7 @@
+     INTERRUPTED, CHILD_ERROR, TEST_DID_NOT_RUN,
+     PROGRESS_MIN_TIME, format_test_result, is_failed)
+ from test.libregrtest.setup import setup_tests
++from test.libregrtest.pgo import setup_pgo_tests
+ from test.libregrtest.utils import removepy, count, format_duration, printlist
+ from test import support
+ 
+@@ -214,6 +215,9 @@ def find_tests(self, tests):
+ 
+         removepy(self.tests)
+ 
++        # add default PGO tests if no tests are specified
++        setup_pgo_tests(self.ns)
++
+         stdtests = STDTESTS[:]
+         nottests = NOTTESTS.copy()
+         if self.ns.exclude:
+diff --git a/Lib/test/libregrtest/pgo.py b/Lib/test/libregrtest/pgo.py
+new file mode 100644
+index 0000000000000..327f19374c3ff
+--- /dev/null
++++ b/Lib/test/libregrtest/pgo.py
+@@ -0,0 +1,52 @@
++# Set of tests run by default if --pgo is specified.  The tests below were
++# chosen based on the following criteria: either they exercise a commonly used
++# C extension module or type, or they run some relatively typical Python code.
++# Long running tests should be avoided because the PGO instrumented executable
++# runs slowly.
++PGO_TESTS = [
++    'test_array',
++    'test_base64',
++    'test_binascii',
++    'test_binop',
++    'test_bisect',
++    'test_bytes',
++    'test_cmath',
++    'test_codecs',
++    'test_collections',
++    'test_complex',
++    'test_dataclasses',
++    'test_datetime',
++    'test_decimal',
++    'test_difflib',
++    'test_embed',
++    'test_float',
++    'test_fstring',
++    'test_functools',
++    'test_generators',
++    'test_hashlib',
++    'test_heapq',
++    'test_int',
++    'test_itertools',
++    'test_json',
++    'test_long',
++    'test_math',
++    'test_memoryview',
++    'test_operator',
++    'test_ordered_dict',
++    'test_pickle',
++    'test_pprint',
++    'test_re',
++    'test_set',
++    'test_statistics',
++    'test_struct',
++    'test_tabnanny',
++    'test_time',
++    'test_unicode',
++    'test_xml_etree',
++    'test_xml_etree_c',
++]
++
++def setup_pgo_tests(ns):
++    if not ns.args and not ns.pgo_extended:
++        # run default set of tests for PGO training
++        ns.args = PGO_TESTS[:]
+diff --git a/Makefile.pre.in b/Makefile.pre.in
+index 88abb563600d8..6a9f4b52704d2 100644
+--- a/Makefile.pre.in
++++ b/Makefile.pre.in
+@@ -255,9 +255,10 @@ TCLTK_INCLUDES=	@TCLTK_INCLUDES@
+ TCLTK_LIBS=	@TCLTK_LIBS@
+ 
+ # The task to run while instrumented when building the profile-opt target.
+-# We exclude unittests with -x that take a rediculious amount of time to
+-# run in the instrumented training build or do not provide much value.
+-PROFILE_TASK=-m test.regrtest --pgo
++# To speed up profile generation, we don't run the full unit test suite
++# by default. The default is "-m test --pgo". To run more tests, use
++# PROFILE_TASK="-m test --pgo-extended"
++PROFILE_TASK=	@PROFILE_TASK@
+ 
+ # report files for gcov / lcov coverage report
+ COVERAGE_INFO=	$(abs_builddir)/coverage.info
+diff --git a/Misc/NEWS.d/next/Build/2019-07-11-01-28-24.bpo-36044.gIgfiJ.rst b/Misc/NEWS.d/next/Build/2019-07-11-01-28-24.bpo-36044.gIgfiJ.rst
+new file mode 100644
+index 0000000000000..177c4cb6d17c7
+--- /dev/null
++++ b/Misc/NEWS.d/next/Build/2019-07-11-01-28-24.bpo-36044.gIgfiJ.rst
+@@ -0,0 +1,9 @@
++Reduce the number of unit tests run for the PGO generation task.  This
++speeds up the task by a factor of about 15x.  Running the full unit test
++suite is slow.  This change may result in a slightly less optimized build
++since not as many code branches will be executed.  If you are willing to
++wait for the much slower build, the old behavior can be restored using
++'./configure [..] PROFILE_TASK="-m test --pgo-extended"'.  We make no
++guarantees as to which PGO task set produces a faster build.  Users who
++care should run their own relevant benchmarks as results can depend on
++the environment, workload, and compiler tool chain.
+diff --git a/configure b/configure
+index 6e7f277bace9b..cb5f130d38e05 100755
+--- a/configure
++++ b/configure
+@@ -686,6 +686,7 @@ target_vendor
+ target_cpu
+ target
+ LLVM_AR
++PROFILE_TASK
+ DEF_MAKE_RULE
+ DEF_MAKE_ALL_RULE
+ ABIFLAGS
+@@ -856,6 +857,7 @@ LDFLAGS
+ LIBS
+ CPPFLAGS
+ CPP
++PROFILE_TASK
+ PKG_CONFIG
+ PKG_CONFIG_PATH
+ PKG_CONFIG_LIBDIR'
+@@ -1559,6 +1561,8 @@ Some influential environment variables:
+   CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
+               you have headers in a nonstandard directory <include dir>
+   CPP         C preprocessor
++  PROFILE_TASK
++              Python args for PGO generation task
+   PKG_CONFIG  path to pkg-config utility
+   PKG_CONFIG_PATH
+               directories to add to pkg-config's search path
+@@ -6426,6 +6430,16 @@ else
+   DEF_MAKE_RULE="all"
+ fi
+ 
++
++{ $as_echo "$as_me:${as_lineno-$LINENO}: checking PROFILE_TASK" >&5
++$as_echo_n "checking PROFILE_TASK... " >&6; }
++if test -z "$PROFILE_TASK"
++then
++	PROFILE_TASK='-m test --pgo'
++fi
++{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $PROFILE_TASK" >&5
++$as_echo "$PROFILE_TASK" >&6; }
++
+ # Make llvm-relatec checks work on systems where llvm tools are not installed with their
+ # normal names in the default $PATH (ie: Ubuntu).  They exist under the
+ # non-suffixed name in their versioned llvm directory.
+diff --git a/configure.ac b/configure.ac
+index 324ce0bd99a9c..b31ed242f1a81 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -1293,6 +1293,14 @@ else
+   DEF_MAKE_RULE="all"
+ fi
+ 
++AC_ARG_VAR(PROFILE_TASK, Python args for PGO generation task)
++AC_MSG_CHECKING(PROFILE_TASK)
++if test -z "$PROFILE_TASK"
++then
++	PROFILE_TASK='-m test --pgo'
++fi
++AC_MSG_RESULT($PROFILE_TASK)
++
+ # Make llvm-relatec checks work on systems where llvm tools are not installed with their
+ # normal names in the default $PATH (ie: Ubuntu).  They exist under the
+ # non-suffixed name in their versioned llvm directory.