https://sourceware.org/bugzilla/show_bug.cgi?id=30358
--- Comment #13 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Michael Matz <m...@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=670c91c0c5eb3fb16d42fe5b2d48a33c64e3ec52 commit 670c91c0c5eb3fb16d42fe5b2d48a33c64e3ec52 Author: Michael Matz <m...@suse.de> Date: Tue Apr 25 17:10:05 2023 +0200 Fix PR30358, performance with --sort-section since af31506c we only use the binary tree when section sorting is required. While its unbalanced and hence can degrade to a linear list it should otherwise have been equivalent to the old code relying on insertion sort. Unfortunately it was not. The old code directly used lang_add_section to populate the sorted list, the new code first populates the tree and only then does lang_add_section on the sorted result. In the testcase we have very many linkonce section groups, and hence lang_add_section won't actually insert anything for most of them. That limited the to-be-sorted list length previously. The tree-sorting code OTOH first created a tree of all candidates sections, including those that wouldn't be inserted by lang_add_section, hence increasing the size of the sorting problem. In the testcase the chain length went from about 1500 to 106000, and in the degenerated case (as in the testcase) that goes in quadratically. This splits out most of the early-out code from lang_add_section to its own function and uses the latter to avoid inserting into the tree. This refactoring slightly changes the order of early-out tests (the ones based on section flags is now done last, and only in lang_add_section). The new function is not a pure predicate: it can give warnings and it might change output_section, like the old early-out code did. I have also added a skip-warning case in the first discard case, whose non-existence seemed to have been an oversight. PR 30358 * ldlang.c (wont_add_section_p): Split out from ... (lang_add_section): ... here. (output_section_callback_sort): Use wont_add_section_p to not always add sections to the sort tree. -- You are receiving this mail because: You are on the CC list for the bug.
