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
25 namespace art {
26
27 static constexpr size_t KB = 1024;
28 static constexpr size_t MB = KB * KB;
29 static constexpr size_t GB = KB * KB * KB;
30
31 // Runtime sizes.
32 static constexpr size_t kBitsPerByte = 8;
33 static constexpr size_t kBitsPerByteLog2 = 3;
34 static constexpr int kBitsPerIntPtrT = sizeof(intptr_t) * kBitsPerByte;
35
36 // Required stack alignment
37 static 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.
41 static constexpr int kPageSize = 4096;
42
43 // Returns whether the given memory offset can be used for generating
44 // an implicit null check.
CanDoImplicitNullCheckOn(uintptr_t offset)45 static inline bool CanDoImplicitNullCheckOn(uintptr_t offset) {
46 return offset < kPageSize;
47 }
48
49 // Required object alignment
50 static constexpr size_t kObjectAlignmentShift = 3;
51 static constexpr size_t kObjectAlignment = 1u << kObjectAlignmentShift;
52 static constexpr size_t kLargeObjectAlignment = kPageSize;
53
54 // Whether or not this is a debug build. Useful in conditionals where NDEBUG isn't.
55 #if defined(NDEBUG)
56 static constexpr bool kIsDebugBuild = false;
57 #else
58 static constexpr bool kIsDebugBuild = true;
59 #endif
60
61 // ART_TARGET - Defined for target builds of ART.
62 // ART_TARGET_LINUX - Defined for target Linux builds of ART.
63 // ART_TARGET_ANDROID - Defined for target Android builds of ART.
64 // Note: Either ART_TARGET_LINUX or ART_TARGET_ANDROID need to be set when ART_TARGET is set.
65 // Note: When ART_TARGET_LINUX is defined mem_map.h will not be using Ashmem for memory mappings
66 // (usually only available on Android kernels).
67 #if defined(ART_TARGET)
68 // Useful in conditionals where ART_TARGET isn't.
69 static constexpr bool kIsTargetBuild = true;
70 # if defined(ART_TARGET_LINUX)
71 static constexpr bool kIsTargetLinux = true;
72 # elif defined(ART_TARGET_ANDROID)
73 static constexpr bool kIsTargetLinux = false;
74 # else
75 # error "Either ART_TARGET_LINUX or ART_TARGET_ANDROID needs to be defined for target builds."
76 # endif
77 #else
78 static constexpr bool kIsTargetBuild = false;
79 # if defined(ART_TARGET_LINUX)
80 # error "ART_TARGET_LINUX defined for host build."
81 # elif defined(ART_TARGET_ANDROID)
82 # error "ART_TARGET_ANDROID defined for host build."
83 # else
84 static constexpr bool kIsTargetLinux = false;
85 # endif
86 #endif
87
88 // Additional statically-linked ART binaries (dex2oats, oatdumps, etc.) are
89 // always available on the host
90 #if !defined(ART_TARGET)
91 static constexpr bool kHostStaticBuildEnabled = true;
92 #else
93 static constexpr bool kHostStaticBuildEnabled = false;
94 #endif
95
96 // Garbage collector constants.
97 static constexpr bool kMovingCollector = true;
98 static constexpr bool kMarkCompactSupport = false && kMovingCollector;
99 // True if we allow moving classes.
100 static constexpr bool kMovingClasses = !kMarkCompactSupport;
101
102 // If true, the quick compiler embeds class pointers in the compiled
103 // code, if possible.
104 static constexpr bool kEmbedClassInCode = true;
105
106 #ifdef USE_BAKER_READ_BARRIER
107 static constexpr bool kUseBakerReadBarrier = true;
108 #else
109 static constexpr bool kUseBakerReadBarrier = false;
110 #endif
111
112 #ifdef USE_BROOKS_READ_BARRIER
113 static constexpr bool kUseBrooksReadBarrier = true;
114 #else
115 static constexpr bool kUseBrooksReadBarrier = false;
116 #endif
117
118 #ifdef USE_TABLE_LOOKUP_READ_BARRIER
119 static constexpr bool kUseTableLookupReadBarrier = true;
120 #else
121 static constexpr bool kUseTableLookupReadBarrier = false;
122 #endif
123
124 static constexpr bool kUseBakerOrBrooksReadBarrier = kUseBakerReadBarrier || kUseBrooksReadBarrier;
125 static constexpr bool kUseReadBarrier =
126 kUseBakerReadBarrier || kUseBrooksReadBarrier || kUseTableLookupReadBarrier;
127
128 // Debugging flag that forces the generation of read barriers, but
129 // does not trigger the use of the concurrent copying GC.
130 //
131 // TODO: Remove this flag when the read barriers compiler
132 // instrumentation is completed.
133 static constexpr bool kForceReadBarrier = false;
134 // TODO: Likewise, remove this flag when kForceReadBarrier is removed
135 // and replace it with kUseReadBarrier.
136 static constexpr bool kEmitCompilerReadBarrier = kForceReadBarrier || kUseReadBarrier;
137
138 // If true, references within the heap are poisoned (negated).
139 #ifdef USE_HEAP_POISONING
140 static constexpr bool kPoisonHeapReferences = true;
141 #else
142 static constexpr bool kPoisonHeapReferences = false;
143 #endif
144
145 // If true, enable the tlab allocator by default.
146 #ifdef ART_USE_TLAB
147 static constexpr bool kUseTlab = true;
148 #else
149 static constexpr bool kUseTlab = false;
150 #endif
151
152 // Kinds of tracing clocks.
153 enum class TraceClockSource {
154 kThreadCpu,
155 kWall,
156 kDual, // Both wall and thread CPU clocks.
157 };
158
159 #if defined(__linux__)
160 static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kDual;
161 #else
162 static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kWall;
163 #endif
164
165 static constexpr bool kDefaultMustRelocate = true;
166
167 static constexpr bool kArm32QuickCodeUseSoftFloat = false;
168
169 #ifdef ART_ENABLE_VDEX
170 static constexpr bool kIsVdexEnabled = true;
171 #else
172 static constexpr bool kIsVdexEnabled = false;
173 #endif
174
175 // Size of a heap reference.
176 static constexpr size_t kHeapReferenceSize = sizeof(uint32_t);
177
178 } // namespace art
179
180 #endif // ART_RUNTIME_GLOBALS_H_
181