1 /* 2 * Copyright (c) 1999, 2006, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "incls/_precompiled.incl" 26 #include "incls/_chaitin_windows.cpp.incl" 27 28 // Disallow the use of the frame pointer (EBP) for implicit null exceptions 29 // on win95/98. If we do not do this, the OS gets confused and gives a stack 30 // error. 31 void PhaseRegAlloc::pd_preallocate_hook() { 32 #ifndef _WIN64 33 if (ImplicitNullChecks && !os::win32::is_nt()) { 34 for (uint block_num=1; block_num<_cfg._num_blocks; block_num++) { 35 Block *block = _cfg._blocks[block_num]; 36 37 Node *block_end = block->end(); 38 if (block_end->is_MachNullCheck() && 39 block_end->as_Mach()->ideal_Opcode() != Op_Con) { 40 // The last instruction in the block is an implicit null check. 41 // Fix its input so that it does not load into the frame pointer. 42 _matcher.pd_implicit_null_fixup(block_end->in(1)->as_Mach(), 43 block_end->as_MachNullCheck()->_vidx); 44 } 45 } 46 } 47 #else 48 // WIN64==itanium on XP 49 #endif 50 } 51 52 #ifdef ASSERT 53 // Verify that no implicit null check uses the frame pointer (EBP) as 54 // its register on win95/98. Use of the frame pointer in an implicit 55 // null check confuses the OS, yielding a stack error. 56 void PhaseRegAlloc::pd_postallocate_verify_hook() { 57 #ifndef _WIN64 58 if (ImplicitNullChecks && !os::win32::is_nt()) { 59 for (uint block_num=1; block_num<_cfg._num_blocks; block_num++) { 60 Block *block = _cfg._blocks[block_num]; 61 62 Node *block_end = block->_nodes[block->_nodes.size()-1]; 63 if (block_end->is_MachNullCheck() && block_end->as_Mach()->ideal_Opcode() != Op_Con) { 64 // The last instruction in the block is an implicit 65 // null check. Verify that this instruction does not 66 // use the frame pointer. 67 int reg = get_reg_first(block_end->in(1)->in(block_end->as_MachNullCheck()->_vidx)); 68 assert(reg != EBP_num, 69 "implicit null check using frame pointer on win95/98"); 70 } 71 } 72 } 73 #else 74 // WIN64==itanium on XP 75 #endif 76 } 77 #endif