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authorRoss Burton <ross.burton@intel.com>2018-10-12 14:44:03 +0100
committerRichard Purdie <richard.purdie@linuxfoundation.org>2018-10-14 09:20:56 +0100
commitcd9b883f960c7a654b80ef68481fb6dc2f23d64a (patch)
tree91cb0ce8bc01117e57d6e83fee3cb3c3688a509a /meta
parent64ff0a5e6c76803e76256d941acbe574ad2a33d8 (diff)
downloadpoky-cd9b883f960c7a654b80ef68481fb6dc2f23d64a.tar.gz
python: don't use runtime checks to identify float endianism
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. This is essentially a backport of the Python 3 patch in oe-core 1781b87. (From OE-Core rev: 94cea72a23a374eb616d5642977b45172537beac) Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'meta')
-rw-r--r--meta/recipes-devtools/python/python/float-endian.patch216
-rw-r--r--meta/recipes-devtools/python/python_2.7.15.bb1
2 files changed, 217 insertions, 0 deletions
diff --git a/meta/recipes-devtools/python/python/float-endian.patch b/meta/recipes-devtools/python/python/float-endian.patch
new file mode 100644
index 0000000000..8a5c90aec4
--- /dev/null
+++ b/meta/recipes-devtools/python/python/float-endian.patch
@@ -0,0 +1,216 @@
1Python uses AC_RUN_IFELSE to determine the byte order for floats and doubles,
2and falls back onto "I don't know" if it can't run code. This results in
3crippled floating point numbers in Python, and the regression tests fail.
4
5Instead of running code, take a macro from autoconf-archive which compiles C
6with a special double in which has an ASCII representation, and then greps the
7binary to identify the format.
8
9Upstream-Status: Backport
10Signed-off-by: Ross Burton <ross.burton@intel.com>
11
12From 253f47b28120c42cfe53a4e2f5ed0ab0ed469deb Mon Sep 17 00:00:00 2001
13From: Ross Burton <ross@burtonini.com>
14Date: Wed, 19 Sep 2018 07:25:48 +0100
15Subject: [PATCH] closes bpo-34585: Don't do runtime test to get float byte
16 order. (GH-9085)
17
18Currently configure.ac uses AC_RUN_IFELSE to determine the byte order of doubles, but this silently fails under cross compilation and Python doesn't do floats properly.
19
20Instead, steal a macro from autoconf-archive which compiles code using magic doubles (which encode to ASCII) and grep for the representation in the binary.
21
22RFC because this doesn't yet handle the weird ancient ARMv4 OABI 'mixed-endian' encoding properly. This encoding is ancient and I don't believe the union of "Python 3.8 users" and "OABI users" has anything in. Should the support for this just be dropped too? Alternatively, someone will need to find an OABI toolchain to verify the encoding of the magic double.
23
24Signed-off-by: Ross Burton <ross.burton@intel.com>
25---
26 .../Build/2018-09-18-16-28-31.bpo-34585.CGMu0h.rst | 3 +
27 configure.ac | 76 ++++----------------
28 m4/ax_c_float_words_bigendian.m4 | 83 ++++++++++++++++++++++
29 3 files changed, 99 insertions(+), 63 deletions(-)
30 create mode 100644 Misc/NEWS.d/next/Build/2018-09-18-16-28-31.bpo-34585.CGMu0h.rst
31 create mode 100644 m4/ax_c_float_words_bigendian.m4
32
33diff --git a/configure.ac b/configure.ac
34index 913d5469d0..7672735396 100644
35--- a/configure.ac
36+++ b/configure.ac
37@@ -3835,74 +3835,24 @@ fi],
38 # * Check for various properties of floating point *
39 # **************************************************
40
41-AC_MSG_CHECKING(whether C doubles are little-endian IEEE 754 binary64)
42-AC_CACHE_VAL(ac_cv_little_endian_double, [
43-AC_RUN_IFELSE([AC_LANG_SOURCE([[
44-#include <string.h>
45-int main() {
46- double x = 9006104071832581.0;
47- if (memcmp(&x, "\x05\x04\x03\x02\x01\xff\x3f\x43", 8) == 0)
48- return 0;
49- else
50- return 1;
51-}
52-]])],
53-[ac_cv_little_endian_double=yes],
54-[ac_cv_little_endian_double=no],
55-[ac_cv_little_endian_double=no])])
56-AC_MSG_RESULT($ac_cv_little_endian_double)
57-if test "$ac_cv_little_endian_double" = yes
58-then
59- AC_DEFINE(DOUBLE_IS_LITTLE_ENDIAN_IEEE754, 1,
60- [Define if C doubles are 64-bit IEEE 754 binary format, stored
61- with the least significant byte first])
62-fi
63-
64-AC_MSG_CHECKING(whether C doubles are big-endian IEEE 754 binary64)
65-AC_CACHE_VAL(ac_cv_big_endian_double, [
66-AC_RUN_IFELSE([AC_LANG_SOURCE([[
67-#include <string.h>
68-int main() {
69- double x = 9006104071832581.0;
70- if (memcmp(&x, "\x43\x3f\xff\x01\x02\x03\x04\x05", 8) == 0)
71- return 0;
72- else
73- return 1;
74-}
75-]])],
76-[ac_cv_big_endian_double=yes],
77-[ac_cv_big_endian_double=no],
78-[ac_cv_big_endian_double=no])])
79-AC_MSG_RESULT($ac_cv_big_endian_double)
80-if test "$ac_cv_big_endian_double" = yes
81+AX_C_FLOAT_WORDS_BIGENDIAN
82+if test "$ax_cv_c_float_words_bigendian" = "yes"
83 then
84 AC_DEFINE(DOUBLE_IS_BIG_ENDIAN_IEEE754, 1,
85 [Define if C doubles are 64-bit IEEE 754 binary format, stored
86 with the most significant byte first])
87-fi
88-
89-# Some ARM platforms use a mixed-endian representation for doubles.
90-# While Python doesn't currently have full support for these platforms
91-# (see e.g., issue 1762561), we can at least make sure that float <-> string
92-# conversions work.
93-AC_MSG_CHECKING(whether C doubles are ARM mixed-endian IEEE 754 binary64)
94-AC_CACHE_VAL(ac_cv_mixed_endian_double, [
95-AC_RUN_IFELSE([AC_LANG_SOURCE([[
96-#include <string.h>
97-int main() {
98- double x = 9006104071832581.0;
99- if (memcmp(&x, "\x01\xff\x3f\x43\x05\x04\x03\x02", 8) == 0)
100- return 0;
101- else
102- return 1;
103-}
104-]])],
105-[ac_cv_mixed_endian_double=yes],
106-[ac_cv_mixed_endian_double=no],
107-[ac_cv_mixed_endian_double=no])])
108-AC_MSG_RESULT($ac_cv_mixed_endian_double)
109-if test "$ac_cv_mixed_endian_double" = yes
110+elif test "$ax_cv_c_float_words_bigendian" = "no"
111 then
112+ AC_DEFINE(DOUBLE_IS_LITTLE_ENDIAN_IEEE754, 1,
113+ [Define if C doubles are 64-bit IEEE 754 binary format, stored
114+ with the least significant byte first])
115+else
116+ # Some ARM platforms use a mixed-endian representation for doubles.
117+ # While Python doesn't currently have full support for these platforms
118+ # (see e.g., issue 1762561), we can at least make sure that float <-> string
119+ # conversions work.
120+ # FLOAT_WORDS_BIGENDIAN doesnt actually detect this case, but if it's not big
121+ # or little, then it must be this?
122 AC_DEFINE(DOUBLE_IS_ARM_MIXED_ENDIAN_IEEE754, 1,
123 [Define if C doubles are 64-bit IEEE 754 binary format, stored
124 in ARM mixed-endian order (byte order 45670123)])
125diff --git a/m4/ax_c_float_words_bigendian.m4 b/m4/ax_c_float_words_bigendian.m4
126new file mode 100644
127index 0000000000..216b90d803
128--- /dev/null
129+++ b/m4/ax_c_float_words_bigendian.m4
130@@ -0,0 +1,83 @@
131+# ===============================================================================
132+# https://www.gnu.org/software/autoconf-archive/ax_c_float_words_bigendian.html
133+# ===============================================================================
134+#
135+# SYNOPSIS
136+#
137+# AX_C_FLOAT_WORDS_BIGENDIAN([ACTION-IF-TRUE], [ACTION-IF-FALSE], [ACTION-IF-UNKNOWN])
138+#
139+# DESCRIPTION
140+#
141+# Checks the ordering of words within a multi-word float. This check is
142+# necessary because on some systems (e.g. certain ARM systems), the float
143+# word ordering can be different from the byte ordering. In a multi-word
144+# float context, "big-endian" implies that the word containing the sign
145+# bit is found in the memory location with the lowest address. This
146+# implementation was inspired by the AC_C_BIGENDIAN macro in autoconf.
147+#
148+# The endianness is detected by first compiling C code that contains a
149+# special double float value, then grepping the resulting object file for
150+# certain strings of ASCII values. The double is specially crafted to have
151+# a binary representation that corresponds with a simple string. In this
152+# implementation, the string "noonsees" was selected because the
153+# individual word values ("noon" and "sees") are palindromes, thus making
154+# this test byte-order agnostic. If grep finds the string "noonsees" in
155+# the object file, the target platform stores float words in big-endian
156+# order. If grep finds "seesnoon", float words are in little-endian order.
157+# If neither value is found, the user is instructed to specify the
158+# ordering.
159+#
160+# LICENSE
161+#
162+# Copyright (c) 2008 Daniel Amelang <dan@amelang.net>
163+#
164+# Copying and distribution of this file, with or without modification, are
165+# permitted in any medium without royalty provided the copyright notice
166+# and this notice are preserved. This file is offered as-is, without any
167+# warranty.
168+
169+#serial 11
170+
171+AC_DEFUN([AX_C_FLOAT_WORDS_BIGENDIAN],
172+ [AC_CACHE_CHECK(whether float word ordering is bigendian,
173+ ax_cv_c_float_words_bigendian, [
174+
175+ax_cv_c_float_words_bigendian=unknown
176+AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
177+
178+double d = 90904234967036810337470478905505011476211692735615632014797120844053488865816695273723469097858056257517020191247487429516932130503560650002327564517570778480236724525140520121371739201496540132640109977779420565776568942592.0;
179+
180+]])], [
181+
182+if grep noonsees conftest.$ac_objext >/dev/null ; then
183+ ax_cv_c_float_words_bigendian=yes
184+fi
185+if grep seesnoon conftest.$ac_objext >/dev/null ; then
186+ if test "$ax_cv_c_float_words_bigendian" = unknown; then
187+ ax_cv_c_float_words_bigendian=no
188+ else
189+ ax_cv_c_float_words_bigendian=unknown
190+ fi
191+fi
192+
193+])])
194+
195+case $ax_cv_c_float_words_bigendian in
196+ yes)
197+ m4_default([$1],
198+ [AC_DEFINE([FLOAT_WORDS_BIGENDIAN], 1,
199+ [Define to 1 if your system stores words within floats
200+ with the most significant word first])]) ;;
201+ no)
202+ $2 ;;
203+ *)
204+ m4_default([$3],
205+ [AC_MSG_ERROR([
206+
207+Unknown float word ordering. You need to manually preset
208+ax_cv_c_float_words_bigendian=no (or yes) according to your system.
209+
210+ ])]) ;;
211+esac
212+
213+])# AX_C_FLOAT_WORDS_BIGENDIAN
214--
2152.11.0
216
diff --git a/meta/recipes-devtools/python/python_2.7.15.bb b/meta/recipes-devtools/python/python_2.7.15.bb
index e7010bb689..e3a4ddb327 100644
--- a/meta/recipes-devtools/python/python_2.7.15.bb
+++ b/meta/recipes-devtools/python/python_2.7.15.bb
@@ -30,6 +30,7 @@ SRC_URI += "\
30 file://add-CROSSPYTHONPATH-for-PYTHON_FOR_BUILD.patch \ 30 file://add-CROSSPYTHONPATH-for-PYTHON_FOR_BUILD.patch \
31 file://pass-missing-libraries-to-Extension-for-mul.patch \ 31 file://pass-missing-libraries-to-Extension-for-mul.patch \
32 file://support_SOURCE_DATE_EPOCH_in_py_compile_2.7.patch \ 32 file://support_SOURCE_DATE_EPOCH_in_py_compile_2.7.patch \
33 file://float-endian.patch \
33" 34"
34 35
35S = "${WORKDIR}/Python-${PV}" 36S = "${WORKDIR}/Python-${PV}"