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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Matplotlib generates invalid ft2font if -fno-lto gcc CFLAGS used","articleBody":"### Bug report\r\n\r\n**Bug summary**\r\n\r\nIf matplotlib is build with -fno-lto CFLAGS then the build is completed \"successfully\" but will fail to import\r\nThis was 1st spotted with matplotlib-3.3.0  and did not occur again with later versions until 3.3.3\r\n\r\n\r\nTEST 1: \r\nCFLAGS=\"-O2 -pipe -fomit-frame-pointer -march=native\" \r\n\r\n```\r\nemerge matplotlib\r\nCalculating dependencies... done!\r\n\u003e\u003e\u003eVerifying ebuild manifests\r\n\u003e\u003e\u003eEmerging (1 of 1) dev-python/matplotlib-3.3.3::gentoo\r\n\u003e\u003e\u003eInstalling (1 of 1) dev-python/matplotlib-3.3.3::gentoo\r\n\u003e\u003e\u003e Jobs: 1 of 1 complete                           Load avg: 0.93, 0.65, 0.92\r\n\u003e\u003e\u003eAuto-cleaning packages...\r\n```\r\n```\r\nfluidmotion ~ # python\r\nPython 3.8.7 (default, Dec 22 2020, 17:30:32)\r\n[GCC 10.2.0] on linux\r\nType \"help\", \"copyright\", \"credits\" or \"license\" for more information.\r\n\u003e\u003e\u003e import matplotlib\r\n\u003e\u003e\u003e\r\n\r\n```\r\n\r\n\r\nBUILD LOG: dev-python:matplotlib-3.3.3:20210103-123758.log\r\n\r\n---------------------------------------------------------------------------\r\n\r\nTEST 2: \r\nCFLAGS=\"-O2 -pipe -fomit-frame-pointer -march=native -fno-lto\" \r\n\r\n```\r\nemerge matplotlib\r\nCalculating dependencies... done!\r\n\u003e\u003e\u003e Verifying ebuild manifests\r\n\u003e\u003e\u003e Emerging (1 of 1) dev-python/matplotlib-3.3.3::gentoo\r\n\u003e\u003e\u003e Installing (1 of 1) dev-python/matplotlib-3.3.3::gentoo\r\n\u003e\u003e\u003e Jobs: 1 of 1 complete                           Load avg: 0.73, 0.57, 0.84\r\n\u003e\u003e\u003e Auto-cleaning packages...\r\n```\r\n```\r\nfluidmotion /var/log/portage # python\r\nPython 3.8.7 (default, Dec 22 2020, 17:30:32)\r\n[GCC 10.2.0] on linux\r\nType \"help\", \"copyright\", \"credits\" or \"license\" for more information.\r\n\u003e\u003e\u003e import matplotlib\r\n\r\nTraceback (most recent call last):\r\n  File \"\u003cstdin\u003e\", line 1, in \u003cmodule\u003e\r\n  File \"/usr/lib/python3.8/site-packages/matplotlib/__init__.py\", line 174, in \u003cmodule\u003e\r\n    _check_versions()\r\n  File \"/usr/lib/python3.8/site-packages/matplotlib/__init__.py\", line 159, in _check_versions\r\n    from . import ft2font\r\nImportError: dynamic module does not define module export function (PyInit_ft2font)\r\n\u003e\u003e\u003e\r\n```\r\n\r\nBUILD LOG:dev-python:matplotlib-3.3.3:20210103-124106.log\r\n\r\n\r\n\r\nDifference:\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/checkdep_freetype2.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/checkdep_freetype2.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/ft2font.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/ft2font.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/ft2font_wrapper.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/ft2font_wrapper.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/mplutils.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/mplutils.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/py_converters.o: plugin needed to handle lto object\r\n/var/tmp/portage/dev-python/matplotlib-3.3.3/work/matplotlib-3.3.3-python3_8/build/temp.linux-x86_64-3.8/src/py_converters.o: plugin needed to handle lto object\r\n/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/crtendS.o: plugin needed to handle lto object\r\n\r\n\r\n\r\nRAW build logs can be found here:  https://bugs.gentoo.org/736122\r\n","author":{"url":"https://github.com/eeyrjmr","@type":"Person","name":"eeyrjmr"},"datePublished":"2021-01-03T17:33:23.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/19227/matplotlib/issues/19227"}