globals.h revision c528dba35b5faece51ca658fc008b688f8b690ad 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ART_RUNTIME_GLOBALS_H_
18#define ART_RUNTIME_GLOBALS_H_
19
20#include <stddef.h>
21#include <stdint.h>
22
23namespace art {
24
25typedef uint8_t byte;
26typedef intptr_t word;
27typedef uintptr_t uword;
28
29static constexpr size_t KB = 1024;
30static constexpr size_t MB = KB * KB;
31static constexpr size_t GB = KB * KB * KB;
32
33static constexpr size_t kWordSize = sizeof(word);
34static constexpr size_t kPointerSize = sizeof(void*);
35
36static constexpr size_t kBitsPerByte = 8;
37static constexpr size_t kBitsPerByteLog2 = 3;
38static constexpr int kBitsPerWord = kWordSize * kBitsPerByte;
39static constexpr size_t kWordHighBitMask = 1 << (kBitsPerWord - 1);
40
41// Required stack alignment
42static constexpr size_t kStackAlignment = 16;
43
44// Required object alignment
45static constexpr size_t kObjectAlignment = 8;
46
47// ARM instruction alignment. ARM processors require code to be 4-byte aligned,
48// but ARM ELF requires 8..
49static constexpr size_t kArmAlignment = 8;
50
51// MIPS instruction alignment.  MIPS processors require code to be 4-byte aligned.
52// TODO: Can this be 4?
53static constexpr size_t kMipsAlignment = 8;
54
55// X86 instruction alignment. This is the recommended alignment for maximum performance.
56static constexpr size_t kX86Alignment = 16;
57
58// System page size. We check this against sysconf(_SC_PAGE_SIZE) at runtime, but use a simple
59// compile-time constant so the compiler can generate better code.
60static constexpr int kPageSize = 4096;
61
62// Whether or not this is a debug build. Useful in conditionals where NDEBUG isn't.
63#if defined(NDEBUG)
64static constexpr bool kIsDebugBuild = false;
65#else
66static constexpr bool kIsDebugBuild = true;
67#endif
68
69// Whether or not this is a target (vs host) build. Useful in conditionals where ART_TARGET isn't.
70#if defined(ART_TARGET)
71static constexpr bool kIsTargetBuild = true;
72#else
73static constexpr bool kIsTargetBuild = false;
74#endif
75
76#if defined(ART_USE_PORTABLE_COMPILER)
77static constexpr bool kUsePortableCompiler = true;
78#else
79static constexpr bool kUsePortableCompiler = false;
80#endif
81
82// Garbage collector constants.
83static constexpr bool kMovingCollector = true && !kUsePortableCompiler;
84// True if we allow moving classes.
85static constexpr bool kMovingClasses = true;
86// True if we allow moving fields.
87static constexpr bool kMovingFields = false;
88// True if we allow moving methods.
89static constexpr bool kMovingMethods = false;
90
91}  // namespace art
92
93#endif  // ART_RUNTIME_GLOBALS_H_
94