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From: Alexandre Oliva <aoliva@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] hardcfr: add checking at exceptions and noreturn calls: tweaks Date: Thu, 11 Aug 2022 02:20:12 +0000 (GMT) [thread overview] Message-ID: <20220811022012.3C84B3857361@sourceware.org> (raw) https://gcc.gnu.org/g:b9aac092373a7314baaa4dec8efe6a15eb7c10d4 commit b9aac092373a7314baaa4dec8efe6a15eb7c10d4 Author: Alexandre Oliva <oliva@gnu.org> Date: Wed Aug 10 22:56:28 2022 -0300 hardcfr: add checking at exceptions and noreturn calls: tweaks Diff: --- gcc/gimple-harden-control-flow.cc | 122 +++++++++++++++++++++----------------- 1 file changed, 67 insertions(+), 55 deletions(-) diff --git a/gcc/gimple-harden-control-flow.cc b/gcc/gimple-harden-control-flow.cc index 5066a43fe6c..849812a6c3f 100644 --- a/gcc/gimple-harden-control-flow.cc +++ b/gcc/gimple-harden-control-flow.cc @@ -729,10 +729,12 @@ public: unsigned int pass_harden_control_flow_redundancy::execute (function *fun) { + bool param_check_at_escaping_exceptions = true; + bool param_check_before_noreturn_calls = true; basic_block bb_eh_cleanup = NULL; basic_block bb; - if (flag_exceptions) + if (param_check_at_escaping_exceptions && flag_exceptions) { int lp_eh_cleanup = -1; @@ -768,14 +770,15 @@ pass_harden_control_flow_redundancy::execute (function *fun) if (!stmt_ends_bb_p (stmt)) split_block (bb, stmt); + /* A noreturn call needs not be associated with the + cleanup handler, because we'll add checking before + the call. */ + else if (EDGE_COUNT (bb->succs) == 0) + continue; if (!bb_eh_cleanup) { bb_eh_cleanup = create_empty_bb (bb); - if (dom_info_available_p (CDI_DOMINATORS)) - set_immediate_dominator (CDI_DOMINATORS, bb_eh_cleanup, bb); - if (current_loops) - add_bb_to_loop (bb_eh_cleanup, current_loops->tree_root); /* Make the new block an EH cleanup for the call. */ eh_region new_r = gen_eh_region_cleanup (NULL); @@ -791,15 +794,20 @@ pass_harden_control_flow_redundancy::execute (function *fun) gresx *resx = gimple_build_resx (new_r->index); gsi_insert_before (&ehgsi, resx, GSI_SAME_STMT); } - else - { - // Update immedite dominator and loop? - } add_stmt_to_eh_lp (stmt, lp_eh_cleanup); /* Finally, wire the EH cleanup block into the CFG. */ make_eh_edges (stmt); } } + + if (bb_eh_cleanup && dom_info_available_p (CDI_DOMINATORS)) + { + basic_block immdom; + immdom = recompute_dominator (CDI_DOMINATORS, bb_eh_cleanup); + set_immediate_dominator (CDI_DOMINATORS, bb_eh_cleanup, immdom); + } + if (bb_eh_cleanup && current_loops) + add_bb_to_loop (bb_eh_cleanup, current_loops->tree_root); } /* We wish to add verification at blocks without successors, such as @@ -809,57 +817,61 @@ pass_harden_control_flow_redundancy::execute (function *fun) int count_noreturn = 0; auto_sbitmap noreturn_blocks (last_basic_block_for_fn (fun)); bitmap_clear (noreturn_blocks); - FOR_EACH_BB_FN (bb, fun) - { - if (EDGE_COUNT (bb->succs) == 0) - { - if (bitmap_set_bit (noreturn_blocks, bb->index)) - count_noreturn++; + if (!param_check_before_noreturn_calls) + FOR_EACH_BB_FN (bb, fun) + { + if (EDGE_COUNT (bb->succs) == 0) + { + if (bitmap_set_bit (noreturn_blocks, bb->index)) + count_noreturn++; + continue; + } + + /* If there are no exceptions, then any noreturn call must have + zero successor edges. Otherwise, check for blocks without + non-EH successors, but skip those with resx stmts and edges + (i.e., those other than that in bb_eh_cleanup), since those + will go through bb_eh_cleanup, that will have been counted as + noreturn above because it has no successors. */ + gcc_checking_assert (bb != bb_eh_cleanup); + if (!flag_exceptions) continue; - } - /* If there are no exceptions, then any noreturn call must have - zero successor edges. Otherwise, check for blocks without - non-EH successors, but skip those with resx stmts and edges - (i.e., those other than that in bb_eh_cleanup), since those - will go through bb_eh_cleanup, that will have been counted as - noreturn above because it has no successors. */ - gcc_checking_assert (bb != bb_eh_cleanup); - if (!flag_exceptions) - continue; - - bool found_non_eh_edge = false; - bool found_eh_edge = false; - edge e; - edge_iterator ei; - FOR_EACH_EDGE (e, ei, bb->succs) - { - if ((e->flags & EDGE_EH)) - found_eh_edge = true; - else - found_non_eh_edge = true; - if (found_non_eh_edge && found_eh_edge) - break; - } + bool found_non_eh_edge = false; + bool found_eh_edge = false; + edge e; + edge_iterator ei; + FOR_EACH_EDGE (e, ei, bb->succs) + { + if ((e->flags & EDGE_EH)) + found_eh_edge = true; + else + found_non_eh_edge = true; + if (found_non_eh_edge && found_eh_edge) + break; + } - if (found_non_eh_edge) - continue; + if (found_non_eh_edge) + continue; - if (found_eh_edge) - { - /* We don't wish to check before (re?)raises, those will - have checking performed at bb_eh_cleanup. The one - exception is bb_eh_cleanup itself. */ - gimple_stmt_iterator gsi = gsi_last_bb (bb); - gcc_checking_assert (!gsi_end_p (gsi)); - gimple *stmt = gsi_stmt (gsi); - if (is_a <gresx *> (stmt)) - continue; - } + if (found_eh_edge) + { + /* We don't wish to check before (re?)raises, those will + have checking performed at bb_eh_cleanup. The one + exception is bb_eh_cleanup itself. */ + gimple_stmt_iterator gsi = gsi_last_bb (bb); + gcc_checking_assert (!gsi_end_p (gsi)); + gimple *stmt = gsi_stmt (gsi); + if (is_a <gresx *> (stmt)) + continue; + } - if (bitmap_set_bit (noreturn_blocks, bb->index)) - count_noreturn++; - } + if (bitmap_set_bit (noreturn_blocks, bb->index)) + count_noreturn++; + } + else if (bb_eh_cleanup + && bitmap_set-bit (noreturn_blocks, bb_eh_cleanup->index)) + count_noreturn++; gcc_checking_assert (!bb_eh_cleanup || bitmap_bit_p (noreturn_blocks, bb_eh_cleanup->index));
next reply other threads:[~2022-08-11 2:20 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-08-11 2:20 Alexandre Oliva [this message] -- strict thread matches above, loose matches on Subject: below -- 2022-08-24 22:59 Alexandre Oliva 2022-08-24 22:46 Alexandre Oliva 2022-08-24 19:39 Alexandre Oliva 2022-08-24 17:18 Alexandre Oliva 2022-08-24 16:53 Alexandre Oliva 2022-08-11 7:28 Alexandre Oliva 2022-08-11 7:13 Alexandre Oliva 2022-08-11 7:07 Alexandre Oliva 2022-08-11 6:54 Alexandre Oliva 2022-08-11 6:43 Alexandre Oliva 2022-08-11 5:45 Alexandre Oliva 2022-08-11 5:22 Alexandre Oliva 2022-08-11 5:20 Alexandre Oliva 2022-08-11 5:17 Alexandre Oliva 2022-08-11 5:08 Alexandre Oliva 2022-08-11 4:24 Alexandre Oliva 2022-08-11 4:13 Alexandre Oliva 2022-08-11 2:50 Alexandre Oliva 2022-08-11 2:34 Alexandre Oliva 2022-08-11 2:24 Alexandre Oliva 2022-08-11 1:57 Alexandre Oliva
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