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_LIBARTBASE_BASE_GLOBALS_H_ 18 #define ART_LIBARTBASE_BASE_GLOBALS_H_ 19 20 #include <stddef.h> 21 #include <stdint.h> 22 23 namespace art { 24 25 static constexpr size_t KB = 1024; 26 static constexpr size_t MB = KB * KB; 27 static constexpr size_t GB = KB * KB * KB; 28 29 // Runtime sizes. 30 static constexpr size_t kBitsPerByte = 8; 31 static constexpr size_t kBitsPerByteLog2 = 3; 32 static constexpr int kBitsPerIntPtrT = sizeof(intptr_t) * kBitsPerByte; 33 34 // Required stack alignment 35 static constexpr size_t kStackAlignment = 16; 36 37 // System page size. We check this against sysconf(_SC_PAGE_SIZE) at runtime, but use a simple 38 // compile-time constant so the compiler can generate better code. 39 static constexpr int kPageSize = 4096; 40 41 // Returns whether the given memory offset can be used for generating 42 // an implicit null check. 43 static inline bool CanDoImplicitNullCheckOn(uintptr_t offset) { 44 return offset < kPageSize; 45 } 46 47 // Required object alignment 48 static constexpr size_t kObjectAlignmentShift = 3; 49 static constexpr size_t kObjectAlignment = 1u << kObjectAlignmentShift; 50 static constexpr size_t kLargeObjectAlignment = kPageSize; 51 52 // Clion, clang analyzer, etc can falsely believe that "if (kIsDebugBuild)" always 53 // returns the same value. By wrapping into a call to another constexpr function, we force it 54 // to realize that is not actually always evaluating to the same value. 55 static constexpr bool GlobalsReturnSelf(bool self) { return self; } 56 57 // Whether or not this is a debug build. Useful in conditionals where NDEBUG isn't. 58 // TODO: Use only __clang_analyzer__ here. b/64455231 59 #if defined(NDEBUG) && !defined(__CLION_IDE__) 60 static constexpr bool kIsDebugBuild = GlobalsReturnSelf(false); 61 #else 62 static constexpr bool kIsDebugBuild = GlobalsReturnSelf(true); 63 #endif 64 65 #if defined(ART_PGO_INSTRUMENTATION) 66 static constexpr bool kIsPGOInstrumentation = true; 67 #else 68 static constexpr bool kIsPGOInstrumentation = false; 69 #endif 70 71 // ART_TARGET - Defined for target builds of ART. 72 // ART_TARGET_LINUX - Defined for target Linux builds of ART. 73 // ART_TARGET_ANDROID - Defined for target Android builds of ART. 74 // Note: Either ART_TARGET_LINUX or ART_TARGET_ANDROID need to be set when ART_TARGET is set. 75 // Note: When ART_TARGET_LINUX is defined mem_map.h will not be using Ashmem for memory mappings 76 // (usually only available on Android kernels). 77 #if defined(ART_TARGET) 78 // Useful in conditionals where ART_TARGET isn't. 79 static constexpr bool kIsTargetBuild = true; 80 # if defined(ART_TARGET_LINUX) 81 static constexpr bool kIsTargetLinux = true; 82 # elif defined(ART_TARGET_ANDROID) 83 static constexpr bool kIsTargetLinux = false; 84 # else 85 # error "Either ART_TARGET_LINUX or ART_TARGET_ANDROID needs to be defined for target builds." 86 # endif 87 #else 88 static constexpr bool kIsTargetBuild = false; 89 # if defined(ART_TARGET_LINUX) 90 # error "ART_TARGET_LINUX defined for host build." 91 # elif defined(ART_TARGET_ANDROID) 92 # error "ART_TARGET_ANDROID defined for host build." 93 # else 94 static constexpr bool kIsTargetLinux = false; 95 # endif 96 #endif 97 98 // Additional statically-linked ART binaries (dex2oats, oatdumps, etc.) are 99 // always available on the host 100 #if !defined(ART_TARGET) 101 static constexpr bool kHostStaticBuildEnabled = true; 102 #else 103 static constexpr bool kHostStaticBuildEnabled = false; 104 #endif 105 106 // Garbage collector constants. 107 static constexpr bool kMovingCollector = true; 108 static constexpr bool kMarkCompactSupport = false && kMovingCollector; 109 // True if we allow moving classes. 110 static constexpr bool kMovingClasses = !kMarkCompactSupport; 111 112 // If true, enable the tlab allocator by default. 113 #ifdef ART_USE_TLAB 114 static constexpr bool kUseTlab = true; 115 #else 116 static constexpr bool kUseTlab = false; 117 #endif 118 119 // Kinds of tracing clocks. 120 enum class TraceClockSource { 121 kThreadCpu, 122 kWall, 123 kDual, // Both wall and thread CPU clocks. 124 }; 125 126 #if defined(__linux__) 127 static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kDual; 128 #else 129 static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kWall; 130 #endif 131 132 static constexpr bool kDefaultMustRelocate = true; 133 134 // Size of a heap reference. 135 static constexpr size_t kHeapReferenceSize = sizeof(uint32_t); 136 137 } // namespace art 138 139 #endif // ART_LIBARTBASE_BASE_GLOBALS_H_ 140
