1/* 2 * Copyright (c) 1997, 2015, 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 "precompiled.hpp" 26#include "asm/macroAssembler.hpp" 27#include "asm/macroAssembler.inline.hpp" 28#include "code/icBuffer.hpp" 29#include "gc/shared/collectedHeap.inline.hpp" 30#include "interpreter/bytecodes.hpp" 31#include "memory/resourceArea.hpp" 32#include "nativeInst_x86.hpp" 33#include "oops/oop.inline.hpp" 34 35int InlineCacheBuffer::ic_stub_code_size() { 36 // Worst case, if destination is not a near call: 37 // lea rax, lit1 38 // lea scratch, lit2 39 // jmp scratch 40 41 // Best case 42 // lea rax, lit1 43 // jmp lit2 44 45 int best = NativeMovConstReg::instruction_size + NativeJump::instruction_size; 46 int worst = 2 * NativeMovConstReg::instruction_size + 3; 47 return MAX2(best, worst); 48} 49 50 51 52void InlineCacheBuffer::assemble_ic_buffer_code(address code_begin, void* cached_value, address entry_point) { 53 ResourceMark rm; 54 CodeBuffer code(code_begin, ic_stub_code_size()); 55 MacroAssembler* masm = new MacroAssembler(&code); 56 // note: even though the code contains an embedded value, we do not need reloc info 57 // because 58 // (1) the value is old (i.e., doesn't matter for scavenges) 59 // (2) these ICStubs are removed *before* a GC happens, so the roots disappear 60 // assert(cached_value == NULL || cached_oop->is_perm(), "must be perm oop"); 61 masm->lea(rax, AddressLiteral((address) cached_value, relocInfo::metadata_type)); 62 masm->jump(ExternalAddress(entry_point)); 63} 64 65 66address InlineCacheBuffer::ic_buffer_entry_point(address code_begin) { 67 NativeMovConstReg* move = nativeMovConstReg_at(code_begin); // creation also verifies the object 68 address jmp = move->next_instruction_address(); 69 NativeInstruction* ni = nativeInstruction_at(jmp); 70 if (ni->is_jump()) { 71 NativeJump* jump = nativeJump_at(jmp); 72 return jump->jump_destination(); 73 } else { 74 assert(ni->is_far_jump(), "unexpected instruction"); 75 NativeFarJump* jump = nativeFarJump_at(jmp); 76 return jump->jump_destination(); 77 } 78} 79 80 81void* InlineCacheBuffer::ic_buffer_cached_value(address code_begin) { 82 // creation also verifies the object 83 NativeMovConstReg* move = nativeMovConstReg_at(code_begin); 84 // Verifies the jump 85 address jmp = move->next_instruction_address(); 86 NativeInstruction* ni = nativeInstruction_at(jmp); 87 if (ni->is_jump()) { 88 NativeJump* jump = nativeJump_at(jmp); 89 } else { 90 assert(ni->is_far_jump(), "unexpected instruction"); 91 NativeFarJump* jump = nativeFarJump_at(jmp); 92 } 93 void* o = (void*)move->data(); 94 return o; 95} 96