From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2140) id 8A3C83857BAB; Thu, 11 Aug 2022 02:24:38 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8A3C83857BAB Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Alexandre Oliva To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] hardcfr: add checking at exceptions and noreturn calls: tweaks X-Act-Checkin: gcc X-Git-Author: Alexandre Oliva X-Git-Refname: refs/users/aoliva/heads/testme X-Git-Oldrev: 0ab4e8d54edbf52d34639dedcea3cb19eddb1b7a X-Git-Newrev: c7e2b43a43de1c27ab9e797b87b7fc9c0499c28b Message-Id: <20220811022438.8A3C83857BAB@sourceware.org> Date: Thu, 11 Aug 2022 02:24:38 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Aug 2022 02:24:38 -0000 https://gcc.gnu.org/g:c7e2b43a43de1c27ab9e797b87b7fc9c0499c28b commit c7e2b43a43de1c27ab9e797b87b7fc9c0499c28b Author: Alexandre Oliva 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..235f19c6548 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 (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 (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));