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