[{"id":1762111,"web_url":"http://patchwork.ozlabs.org/comment/1762111/","msgid":"<54FC95A6-AAA0-464A-BFB7-FC27738AFC20@suse.de>","list_archive_url":null,"date":"2017-09-02T11:51:10","subject":"Re: [PATCH] Add UBSAN_{PTR, BOUNDS} folding (PR sanitizer/81981,\n\ttake 2)","submitter":{"id":4338,"url":"http://patchwork.ozlabs.org/api/people/4338/","name":"Richard Biener","email":"rguenther@suse.de"},"content":"On September 1, 2017 10:28:16 PM GMT+02:00, Jakub Jelinek wrote:\n>On Fri, Sep 01, 2017 at 07:10:51PM +0200, Richard Biener wrote:\n>> OK, I thought we have one. Can you add a helper for it please? \n>> replace_with_nop or so? I thought there's maybe replace_with_value\n>which\n>> handles null lhs by replacing with nop. (can't check, writing from\n>phone)\n>\n>Actually, you're right, replace_call_with_value does the right thing\n>when called on call without lhs (all these internal fns don't have\n>lhs),\n>and NULL_TREE val ensures we'd ICE if that ever wasn't the case.\n>\n>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?\n\nOK. \n\nRichard. \n\n>2017-09-01 Jakub Jelinek \n>\n>\tPR sanitizer/81981\n>\t* gimple-fold.c (gimple_fold_call): Optimize away useless UBSAN_PTR\n>\tand UBSAN_BOUNDS internal calls. Clean up IFN_UBSAN_OBJECT_SIZE\n>\thandling. Use replace_call_with_value with NULL instead of\n>\tgsi_replace, unlink_stmt_vdef and release_defs.\n>\n>\t* gcc.dg/ubsan/pr81981.c: New test.\n>\n>--- gcc/gimple-fold.c.jj\t2017-09-01 09:26:37.054748039 +0200\n>+++ gcc/gimple-fold.c\t2017-09-01 19:37:03.283795450 +0200\n>@@ -3936,18 +3936,43 @@ gimple_fold_call (gimple_stmt_iterator *\n> \t\t\t\t\tgimple_call_arg (stmt, 2));\n> \t break;\n> \tcase IFN_UBSAN_OBJECT_SIZE:\n>-\t if (integer_all_onesp (gimple_call_arg (stmt, 2))\n>-\t || (TREE_CODE (gimple_call_arg (stmt, 1)) == INTEGER_CST\n>-\t\t && TREE_CODE (gimple_call_arg (stmt, 2)) == INTEGER_CST\n>-\t\t && tree_int_cst_le (gimple_call_arg (stmt, 1),\n>-\t\t\t\t gimple_call_arg (stmt, 2))))\n>+\t {\n>+\t tree offset = gimple_call_arg (stmt, 1);\n>+\t tree objsize = gimple_call_arg (stmt, 2);\n>+\t if (integer_all_onesp (objsize)\n>+\t\t|| (TREE_CODE (offset) == INTEGER_CST\n>+\t\t && TREE_CODE (objsize) == INTEGER_CST\n>+\t\t && tree_int_cst_le (offset, objsize)))\n>+\t {\n>+\t\treplace_call_with_value (gsi, NULL_TREE);\n>+\t\treturn true;\n>+\t }\n>+\t }\n>+\t break;\n>+\tcase IFN_UBSAN_PTR:\n>+\t if (integer_zerop (gimple_call_arg (stmt, 1)))\n> \t {\n>-\t gsi_replace (gsi, gimple_build_nop (), false);\n>-\t unlink_stmt_vdef (stmt);\n>-\t release_defs (stmt);\n>+\t replace_call_with_value (gsi, NULL_TREE);\n> \t return true;\n> \t }\n> \t break;\n>+\tcase IFN_UBSAN_BOUNDS:\n>+\t {\n>+\t tree index = gimple_call_arg (stmt, 1);\n>+\t tree bound = gimple_call_arg (stmt, 2);\n>+\t if (TREE_CODE (index) == INTEGER_CST\n>+\t\t&& TREE_CODE (bound) == INTEGER_CST)\n>+\t {\n>+\t\tindex = fold_convert (TREE_TYPE (bound), index);\n>+\t\tif (TREE_CODE (index) == INTEGER_CST\n>+\t\t && tree_int_cst_le (index, bound))\n>+\t\t {\n>+\t\t replace_call_with_value (gsi, NULL_TREE);\n>+\t\t return true;\n>+\t\t }\n>+\t }\n>+\t }\n>+\t break;\n> \tcase IFN_GOACC_DIM_SIZE:\n> \tcase IFN_GOACC_DIM_POS:\n> \t result = fold_internal_goacc_dim (stmt);\n>--- gcc/testsuite/gcc.dg/ubsan/pr81981.c.jj\t2017-09-01\n>19:35:37.555782465 +0200\n>+++ gcc/testsuite/gcc.dg/ubsan/pr81981.c\t2017-09-01 19:35:37.555782465\n>+0200\n>@@ -0,0 +1,21 @@\n>+/* PR sanitizer/81981 */\n>+/* { dg-do compile } */\n>+/* { dg-options \"-O2 -Wmaybe-uninitialized -fsanitize=undefined\n>-ffat-lto-objects\" } */\n>+\n>+int v;\n>+\n>+int\n>+foo (int i)\n>+{\n>+ int t[1], u[1];\n>+ int n = 0;\n>+\n>+ if (i)\n>+ {\n>+ t[n] = i;\n>+ u[0] = i;\n>+ }\n>+\n>+ v = u[0];\t\t/* { dg-warning \"may be used uninitialized in this\n>function\" } */\n>+ return t[0];\t\t/* { dg-warning \"may be used uninitialized in this\n>function\" } */\n>+}\n>\n>\n>\tJakub","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":["patchwork-incoming@bilbo.ozlabs.org","mailing list gcc-patches@gcc.gnu.org"],"Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=gcc.gnu.org\n\t(client-ip=209.132.180.131; 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charset=utf-8","Content-Transfer-Encoding":"quoted-printable","Subject":"Re: [PATCH] Add UBSAN_{PTR, BOUNDS} folding (PR sanitizer/81981,\n\ttake 2)","To":"Jakub Jelinek ","CC":"gcc-patches@gcc.gnu.org","From":"Richard Biener ","Message-ID":"<54FC95A6-AAA0-464A-BFB7-FC27738AFC20@suse.de>"}}]