[4/5] python3: don't use runtime checks to identify float endianism

diff --git a/meta/recipes-devtools/python/python3/float-endian.patch b/meta/recipes-devtools/python/python3/float-endian.patch
new file mode 100644
index 00000000000..6ba3f5c252d
--- /dev/null
+++ b/meta/recipes-devtools/python/python3/float-endian.patch
@@ -0,0 +1,212 @@ 
+Python uses AC_RUN_IFELSE to determine the byte order for floats and doubles,
+and falls back onto "I don't know" if it can't run code.  This results in
+crippled floating point numbers in Python, and the regression tests fail.
+
+Instead of running code, take a macro from autoconf-archive which compiles C
+with a special double in which has an ASCII representation, and then greps the
+binary to identify the format.
+
+Upstream-Status: Submitted [https://bugs.python.org/issue34585]
+Signed-off-by: Ross Burton <ross.burton@intel.com>
+
+From 50df2a4c3a65ed06322be7c26d42b06ce81730c1 Mon Sep 17 00:00:00 2001
+From: Ross Burton <ross.burton@intel.com>
+Date: Wed, 5 Sep 2018 11:45:52 +0100
+Subject: [PATCH] Don't do runtime test to get float byte order
+
+---
+ configure.ac                     | 74 +++++------------------------------
+ m4/ax_c_float_words_bigendian.m4 | 83 ++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 92 insertions(+), 65 deletions(-)
+ create mode 100644 m4/ax_c_float_words_bigendian.m4
+
+diff --git a/configure.ac b/configure.ac
+index c9b755f0f4..1215969871 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -9,6 +9,8 @@ AC_PREREQ(2.65)
+ 
+ AC_INIT(python, PYTHON_VERSION, https://bugs.python.org/)
+ 
++AC_CONFIG_MACRO_DIR(m4)
++
+ AC_SUBST(BASECPPFLAGS)
+ if test "$srcdir" != . -a "$srcdir" != "$(pwd)"; then
+     # If we're building out-of-tree, we need to make sure the following
+@@ -4128,77 +4130,19 @@ fi
+ # * Check for various properties of floating point *
+ # **************************************************
+ 
+-AC_MSG_CHECKING(whether C doubles are little-endian IEEE 754 binary64)
+-AC_CACHE_VAL(ac_cv_little_endian_double, [
+-AC_RUN_IFELSE([AC_LANG_SOURCE([[
+-#include <string.h>
+-int main() {
+-    double x = 9006104071832581.0;
+-    if (memcmp(&x, "\x05\x04\x03\x02\x01\xff\x3f\x43", 8) == 0)
+-        return 0;
+-    else
+-        return 1;
+-}
+-]])],
+-[ac_cv_little_endian_double=yes],
+-[ac_cv_little_endian_double=no],
+-[ac_cv_little_endian_double=no])])
+-AC_MSG_RESULT($ac_cv_little_endian_double)
+-if test "$ac_cv_little_endian_double" = yes
+-then
+-  AC_DEFINE(DOUBLE_IS_LITTLE_ENDIAN_IEEE754, 1,
+-  [Define if C doubles are 64-bit IEEE 754 binary format, stored
+-   with the least significant byte first])
+-fi
+-
+-AC_MSG_CHECKING(whether C doubles are big-endian IEEE 754 binary64)
+-AC_CACHE_VAL(ac_cv_big_endian_double, [
+-AC_RUN_IFELSE([AC_LANG_SOURCE([[
+-#include <string.h>
+-int main() {
+-    double x = 9006104071832581.0;
+-    if (memcmp(&x, "\x43\x3f\xff\x01\x02\x03\x04\x05", 8) == 0)
+-        return 0;
+-    else
+-        return 1;
+-}
+-]])],
+-[ac_cv_big_endian_double=yes],
+-[ac_cv_big_endian_double=no],
+-[ac_cv_big_endian_double=no])])
+-AC_MSG_RESULT($ac_cv_big_endian_double)
+-if test "$ac_cv_big_endian_double" = yes
++AX_C_FLOAT_WORDS_BIGENDIAN
++if test "$ax_cv_c_float_words_bigendian" = "yes"
+ then
+   AC_DEFINE(DOUBLE_IS_BIG_ENDIAN_IEEE754, 1,
+   [Define if C doubles are 64-bit IEEE 754 binary format, stored
+    with the most significant byte first])
+-fi
+-
+-# Some ARM platforms use a mixed-endian representation for doubles.
+-# While Python doesn't currently have full support for these platforms
+-# (see e.g., issue 1762561), we can at least make sure that float <-> string
+-# conversions work.
+-AC_MSG_CHECKING(whether C doubles are ARM mixed-endian IEEE 754 binary64)
+-AC_CACHE_VAL(ac_cv_mixed_endian_double, [
+-AC_RUN_IFELSE([AC_LANG_SOURCE([[
+-#include <string.h>
+-int main() {
+-    double x = 9006104071832581.0;
+-    if (memcmp(&x, "\x01\xff\x3f\x43\x05\x04\x03\x02", 8) == 0)
+-        return 0;
+-    else
+-        return 1;
+-}
+-]])],
+-[ac_cv_mixed_endian_double=yes],
+-[ac_cv_mixed_endian_double=no],
+-[ac_cv_mixed_endian_double=no])])
+-AC_MSG_RESULT($ac_cv_mixed_endian_double)
+-if test "$ac_cv_mixed_endian_double" = yes
++elif test "$ax_cv_c_float_words_bigendian" = "no"
+ then
+-  AC_DEFINE(DOUBLE_IS_ARM_MIXED_ENDIAN_IEEE754, 1,
++  AC_DEFINE(DOUBLE_IS_LITTLE_ENDIAN_IEEE754, 1,
+   [Define if C doubles are 64-bit IEEE 754 binary format, stored
+-   in ARM mixed-endian order (byte order 45670123)])
++   with the least significant byte first])
++else
++  AC_MSG_ERROR([Cannot identify floating point byte order])
+ fi
+ 
+ # The short float repr introduced in Python 3.1 requires the
+diff --git a/m4/ax_c_float_words_bigendian.m4 b/m4/ax_c_float_words_bigendian.m4
+new file mode 100644
+index 0000000000..216b90d803
+--- /dev/null
++++ b/m4/ax_c_float_words_bigendian.m4
+@@ -0,0 +1,83 @@
++# ===============================================================================
++#  https://www.gnu.org/software/autoconf-archive/ax_c_float_words_bigendian.html
++# ===============================================================================
++#
++# SYNOPSIS
++#
++#   AX_C_FLOAT_WORDS_BIGENDIAN([ACTION-IF-TRUE], [ACTION-IF-FALSE], [ACTION-IF-UNKNOWN])
++#
++# DESCRIPTION
++#
++#   Checks the ordering of words within a multi-word float. This check is
++#   necessary because on some systems (e.g. certain ARM systems), the float
++#   word ordering can be different from the byte ordering. In a multi-word
++#   float context, "big-endian" implies that the word containing the sign
++#   bit is found in the memory location with the lowest address. This
++#   implementation was inspired by the AC_C_BIGENDIAN macro in autoconf.
++#
++#   The endianness is detected by first compiling C code that contains a
++#   special double float value, then grepping the resulting object file for
++#   certain strings of ASCII values. The double is specially crafted to have
++#   a binary representation that corresponds with a simple string. In this
++#   implementation, the string "noonsees" was selected because the
++#   individual word values ("noon" and "sees") are palindromes, thus making
++#   this test byte-order agnostic. If grep finds the string "noonsees" in
++#   the object file, the target platform stores float words in big-endian
++#   order. If grep finds "seesnoon", float words are in little-endian order.
++#   If neither value is found, the user is instructed to specify the
++#   ordering.
++#
++# LICENSE
++#
++#   Copyright (c) 2008 Daniel Amelang <dan@amelang.net>
++#
++#   Copying and distribution of this file, with or without modification, are
++#   permitted in any medium without royalty provided the copyright notice
++#   and this notice are preserved. This file is offered as-is, without any
++#   warranty.
++
++#serial 11
++
++AC_DEFUN([AX_C_FLOAT_WORDS_BIGENDIAN],
++  [AC_CACHE_CHECK(whether float word ordering is bigendian,
++                  ax_cv_c_float_words_bigendian, [
++
++ax_cv_c_float_words_bigendian=unknown
++AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
++
++double d = 90904234967036810337470478905505011476211692735615632014797120844053488865816695273723469097858056257517020191247487429516932130503560650002327564517570778480236724525140520121371739201496540132640109977779420565776568942592.0;
++
++]])], [
++
++if grep noonsees conftest.$ac_objext >/dev/null ; then
++  ax_cv_c_float_words_bigendian=yes
++fi
++if grep seesnoon conftest.$ac_objext >/dev/null ; then
++  if test "$ax_cv_c_float_words_bigendian" = unknown; then
++    ax_cv_c_float_words_bigendian=no
++  else
++    ax_cv_c_float_words_bigendian=unknown
++  fi
++fi
++
++])])
++
++case $ax_cv_c_float_words_bigendian in
++  yes)
++    m4_default([$1],
++      [AC_DEFINE([FLOAT_WORDS_BIGENDIAN], 1,
++                 [Define to 1 if your system stores words within floats
++                  with the most significant word first])]) ;;
++  no)
++    $2 ;;
++  *)
++    m4_default([$3],
++      [AC_MSG_ERROR([
++
++Unknown float word ordering. You need to manually preset
++ax_cv_c_float_words_bigendian=no (or yes) according to your system.
++
++    ])]) ;;
++esac
++
++])# AX_C_FLOAT_WORDS_BIGENDIAN
+-- 
+2.11.0
+
diff --git a/meta/recipes-devtools/python/python3_3.5.5.bb b/meta/recipes-devtools/python/python3_3.5.5.bb
index aad2e3abe60..b89e3b04c86 100644
--- a/meta/recipes-devtools/python/python3_3.5.5.bb
+++ b/meta/recipes-devtools/python/python3_3.5.5.bb
@@ -41,6 +41,7 @@  SRC_URI += "\
             file://pass-missing-libraries-to-Extension-for-mul.patch \
             file://Use-correct-CFLAGS-for-extensions-when-cross-compili.patch \
             file://0002-Makefile-add-target-to-split-profile-generation.patch \
+			file://float-endian.patch \
            "
 SRC_URI[md5sum] = "f3763edf9824d5d3a15f5f646083b6e0"
 SRC_URI[sha256sum] = "063d2c3b0402d6191b90731e0f735c64830e7522348aeb7ed382a83165d45009"