1 /* |
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2 * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #include "precompiled.hpp" |
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26 #include "opto/chaitin.hpp" |
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27 #include "opto/machnode.hpp" |
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28 |
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29 // Disallow the use of the frame pointer (EBP) for implicit null exceptions |
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30 // on win95/98. If we do not do this, the OS gets confused and gives a stack |
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31 // error. |
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32 void PhaseRegAlloc::pd_preallocate_hook() { |
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33 #ifndef _WIN64 |
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34 if (ImplicitNullChecks && !os::win32::is_nt()) { |
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35 for (uint block_num=1; block_num<_cfg._num_blocks; block_num++) { |
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36 Block *block = _cfg._blocks[block_num]; |
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37 |
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38 Node *block_end = block->end(); |
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39 if (block_end->is_MachNullCheck() && |
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40 block_end->as_Mach()->ideal_Opcode() != Op_Con) { |
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41 // The last instruction in the block is an implicit null check. |
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42 // Fix its input so that it does not load into the frame pointer. |
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43 _matcher.pd_implicit_null_fixup(block_end->in(1)->as_Mach(), |
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44 block_end->as_MachNullCheck()->_vidx); |
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45 } |
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46 } |
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47 } |
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48 #else |
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49 // WIN64==itanium on XP |
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50 #endif |
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51 } |
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52 |
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53 #ifdef ASSERT |
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54 // Verify that no implicit null check uses the frame pointer (EBP) as |
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55 // its register on win95/98. Use of the frame pointer in an implicit |
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56 // null check confuses the OS, yielding a stack error. |
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57 void PhaseRegAlloc::pd_postallocate_verify_hook() { |
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58 #ifndef _WIN64 |
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59 if (ImplicitNullChecks && !os::win32::is_nt()) { |
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60 for (uint block_num=1; block_num<_cfg._num_blocks; block_num++) { |
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61 Block *block = _cfg._blocks[block_num]; |
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62 |
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63 Node *block_end = block->_nodes[block->_nodes.size()-1]; |
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64 if (block_end->is_MachNullCheck() && block_end->as_Mach()->ideal_Opcode() != Op_Con) { |
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65 // The last instruction in the block is an implicit |
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66 // null check. Verify that this instruction does not |
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67 // use the frame pointer. |
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68 int reg = get_reg_first(block_end->in(1)->in(block_end->as_MachNullCheck()->_vidx)); |
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69 assert(reg != EBP_num, |
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70 "implicit null check using frame pointer on win95/98"); |
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71 } |
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72 } |
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73 } |
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74 #else |
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75 // WIN64==itanium on XP |
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76 #endif |
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77 } |
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78 #endif |
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