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
27static constexpr size_t KB = 1024;
28static constexpr size_t MB = KB * KB;
29static constexpr size_t GB = KB * KB * KB;
30
31// Runtime sizes.
32static constexpr size_t kBitsPerByte = 8;
33static constexpr size_t kBitsPerByteLog2 = 3;
34static constexpr int kBitsPerIntPtrT = sizeof(intptr_t) * kBitsPerByte;
35
36// Required stack alignment
37static constexpr size_t kStackAlignment = 16;
38
39// System page size. We check this against sysconf(_SC_PAGE_SIZE) at runtime, but use a simple
40// compile-time constant so the compiler can generate better code.
41static constexpr int kPageSize = 4096;
42
43// Required object alignment
44static constexpr size_t kObjectAlignment = 8;
45static constexpr size_t kLargeObjectAlignment = kPageSize;
46
47// Whether or not this is a debug build. Useful in conditionals where NDEBUG isn't.
48#if defined(NDEBUG)
49static constexpr bool kIsDebugBuild = false;
50#else
51static constexpr bool kIsDebugBuild = true;
52#endif
53
54// Whether or not this is a target (vs host) build. Useful in conditionals where ART_TARGET isn't.
55#if defined(ART_TARGET)
56static constexpr bool kIsTargetBuild = true;
57#else
58static constexpr bool kIsTargetBuild = false;
59#endif
60
61// Garbage collector constants.
62static constexpr bool kMovingCollector = true;
63static constexpr bool kMarkCompactSupport = false && kMovingCollector;
64// True if we allow moving classes.
65static constexpr bool kMovingClasses = !kMarkCompactSupport;
66
67// If true, the quick compiler embeds class pointers in the compiled
68// code, if possible.
69static constexpr bool kEmbedClassInCode = true;
70
71#ifdef USE_BAKER_READ_BARRIER
72static constexpr bool kUseBakerReadBarrier = true;
73#else
74static constexpr bool kUseBakerReadBarrier = false;
75#endif
76
77#ifdef USE_BROOKS_READ_BARRIER
78static constexpr bool kUseBrooksReadBarrier = true;
79#else
80static constexpr bool kUseBrooksReadBarrier = false;
81#endif
82
83#ifdef USE_TABLE_LOOKUP_READ_BARRIER
84static constexpr bool kUseTableLookupReadBarrier = true;
85#else
86static constexpr bool kUseTableLookupReadBarrier = false;
87#endif
88
89static constexpr bool kUseBakerOrBrooksReadBarrier = kUseBakerReadBarrier || kUseBrooksReadBarrier;
90static constexpr bool kUseReadBarrier =
91    kUseBakerReadBarrier || kUseBrooksReadBarrier || kUseTableLookupReadBarrier;
92
93// Debugging flag that forces the generation of read barriers, but
94// does not trigger the use of the concurrent copying GC.
95//
96// TODO: Remove this flag when the read barriers compiler
97// instrumentation is completed.
98static constexpr bool kForceReadBarrier = false;
99// TODO: Likewise, remove this flag when kForceReadBarrier is removed
100// and replace it with kUseReadBarrier.
101static constexpr bool kEmitCompilerReadBarrier = kForceReadBarrier || kUseReadBarrier;
102
103// If true, references within the heap are poisoned (negated).
104#ifdef USE_HEAP_POISONING
105static constexpr bool kPoisonHeapReferences = true;
106#else
107static constexpr bool kPoisonHeapReferences = false;
108#endif
109
110// If true, enable the tlab allocator by default.
111#ifdef ART_USE_TLAB
112static constexpr bool kUseTlab = true;
113#else
114static constexpr bool kUseTlab = false;
115#endif
116
117// Kinds of tracing clocks.
118enum class TraceClockSource {
119  kThreadCpu,
120  kWall,
121  kDual,  // Both wall and thread CPU clocks.
122};
123
124#if defined(__linux__)
125static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kDual;
126#else
127static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kWall;
128#endif
129
130static constexpr bool kDefaultMustRelocate = true;
131
132static constexpr bool kArm32QuickCodeUseSoftFloat = false;
133
134}  // namespace art
135
136#endif  // ART_RUNTIME_GLOBALS_H_
137