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
ic_stub_code_size()35 int 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
assemble_ic_buffer_code(address code_begin,void * cached_value,address entry_point)52 void 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
ic_buffer_entry_point(address code_begin)66 address 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
ic_buffer_cached_value(address code_begin)81 void* 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