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 23namespace art { 24 25static constexpr size_t KB = 1024; 26static constexpr size_t MB = KB * KB; 27static constexpr size_t GB = KB * KB * KB; 28 29// Runtime sizes. 30static constexpr size_t kBitsPerByte = 8; 31static constexpr size_t kBitsPerByteLog2 = 3; 32static constexpr int kBitsPerIntPtrT = sizeof(intptr_t) * kBitsPerByte; 33 34// Required stack alignment 35static 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. 39static constexpr int kPageSize = 4096; 40 41// Returns whether the given memory offset can be used for generating 42// an implicit null check. 43static inline bool CanDoImplicitNullCheckOn(uintptr_t offset) { 44 return offset < kPageSize; 45} 46 47// Required object alignment 48static constexpr size_t kObjectAlignmentShift = 3; 49static constexpr size_t kObjectAlignment = 1u << kObjectAlignmentShift; 50static 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. 55static 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__) 60static constexpr bool kIsDebugBuild = GlobalsReturnSelf(false); 61#else 62static constexpr bool kIsDebugBuild = GlobalsReturnSelf(true); 63#endif 64 65#if defined(ART_PGO_INSTRUMENTATION) 66static constexpr bool kIsPGOInstrumentation = true; 67#else 68static 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. 79static constexpr bool kIsTargetBuild = true; 80# if defined(ART_TARGET_LINUX) 81static constexpr bool kIsTargetLinux = true; 82# elif defined(ART_TARGET_ANDROID) 83static 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 88static 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 94static 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) 101static constexpr bool kHostStaticBuildEnabled = true; 102#else 103static constexpr bool kHostStaticBuildEnabled = false; 104#endif 105 106// Garbage collector constants. 107static constexpr bool kMovingCollector = true; 108static constexpr bool kMarkCompactSupport = false && kMovingCollector; 109// True if we allow moving classes. 110static constexpr bool kMovingClasses = !kMarkCompactSupport; 111 112// If true, enable the tlab allocator by default. 113#ifdef ART_USE_TLAB 114static constexpr bool kUseTlab = true; 115#else 116static constexpr bool kUseTlab = false; 117#endif 118 119// Kinds of tracing clocks. 120enum class TraceClockSource { 121 kThreadCpu, 122 kWall, 123 kDual, // Both wall and thread CPU clocks. 124}; 125 126#if defined(__linux__) 127static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kDual; 128#else 129static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kWall; 130#endif 131 132static constexpr bool kDefaultMustRelocate = true; 133 134// Size of a heap reference. 135static constexpr size_t kHeapReferenceSize = sizeof(uint32_t); 136 137} // namespace art 138 139#endif // ART_LIBARTBASE_BASE_GLOBALS_H_ 140