globals.h revision 345c4b19758703793ed31024cfb79940e2c63b75 
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#include "read_barrier_c.h"
23#include "read_barrier_option.h"
24
25namespace art {
26
27typedef uint8_t byte;
28typedef intptr_t word;
29typedef uintptr_t uword;
30
31static constexpr size_t KB = 1024;
32static constexpr size_t MB = KB * KB;
33static constexpr size_t GB = KB * KB * KB;
34
35// Runtime sizes.
36static constexpr size_t kWordSize = sizeof(word);
37static constexpr size_t kPointerSize = sizeof(void*);
38
39static constexpr size_t kBitsPerByte = 8;
40static constexpr size_t kBitsPerByteLog2 = 3;
41static constexpr int kBitsPerWord = kWordSize * kBitsPerByte;
42static constexpr size_t kWordHighBitMask = static_cast<size_t>(1) << (kBitsPerWord - 1);
43
44// Required stack alignment
45static constexpr size_t kStackAlignment = 16;
46
47// System page size. We check this against sysconf(_SC_PAGE_SIZE) at runtime, but use a simple
48// compile-time constant so the compiler can generate better code.
49static constexpr int kPageSize = 4096;
50
51// Required object alignment
52static constexpr size_t kObjectAlignment = 8;
53static constexpr size_t kLargeObjectAlignment = kPageSize;
54
55// Whether or not this is a debug build. Useful in conditionals where NDEBUG isn't.
56#if defined(NDEBUG)
57static constexpr bool kIsDebugBuild = false;
58#else
59static constexpr bool kIsDebugBuild = true;
60#endif
61
62// Whether or not this is a target (vs host) build. Useful in conditionals where ART_TARGET isn't.
63#if defined(ART_TARGET)
64static constexpr bool kIsTargetBuild = true;
65#else
66static constexpr bool kIsTargetBuild = false;
67#endif
68
69#if defined(ART_USE_PORTABLE_COMPILER)
70static constexpr bool kUsePortableCompiler = true;
71#else
72static constexpr bool kUsePortableCompiler = false;
73#endif
74
75// Garbage collector constants.
76static constexpr bool kMovingCollector = true && !kUsePortableCompiler;
77static constexpr bool kMarkCompactSupport = false && kMovingCollector;
78// True if we allow moving field arrays, this can cause complication with mark compact.
79static constexpr bool kMoveFieldArrays = !kMarkCompactSupport;
80// True if we allow moving classes.
81static constexpr bool kMovingClasses = !kMarkCompactSupport;
82// True if we allow moving fields.
83static constexpr bool kMovingFields = false;
84// True if we allow moving methods.
85static constexpr bool kMovingMethods = false;
86
87// If true, the quick compiler embeds class pointers in the compiled
88// code, if possible.
89static constexpr bool kEmbedClassInCode = true;
90
91#ifdef USE_BAKER_READ_BARRIER
92static constexpr bool kUseBakerReadBarrier = true;
93#else
94static constexpr bool kUseBakerReadBarrier = false;
95#endif
96
97#ifdef USE_BROOKS_READ_BARRIER
98static constexpr bool kUseBrooksReadBarrier = true;
99#else
100static constexpr bool kUseBrooksReadBarrier = false;
101#endif
102
103static constexpr bool kUseBakerOrBrooksReadBarrier = kUseBakerReadBarrier || kUseBrooksReadBarrier;
104
105// If true, references within the heap are poisoned (negated).
106static constexpr bool kPoisonHeapReferences = false;
107
108// Kinds of tracing clocks.
109enum TraceClockSource {
110  kTraceClockSourceThreadCpu,
111  kTraceClockSourceWall,
112  kTraceClockSourceDual,  // Both wall and thread CPU clocks.
113};
114
115#if defined(HAVE_POSIX_CLOCKS)
116static constexpr TraceClockSource kDefaultTraceClockSource = kTraceClockSourceDual;
117#else
118static constexpr TraceClockSource kDefaultTraceClockSource = kTraceClockSourceWall;
119#endif
120
121static constexpr bool kDefaultMustRelocate = true;
122
123}  // namespace art
124
125#endif  // ART_RUNTIME_GLOBALS_H_
126