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_RUNTIME_GLOBALS_H_ 18 #define ART_RUNTIME_RUNTIME_GLOBALS_H_ 19 20 #include "base/globals.h" 21 22 namespace art { 23 24 // Size of Dex virtual registers. 25 static constexpr size_t kVRegSize = 4; 26 27 // Returns whether the given memory offset can be used for generating 28 // an implicit null check. 29 static inline bool CanDoImplicitNullCheckOn(uintptr_t offset) { 30 return offset < kPageSize; 31 } 32 33 // Required object alignment 34 static constexpr size_t kObjectAlignmentShift = 3; 35 static constexpr size_t kObjectAlignment = 1u << kObjectAlignmentShift; 36 static constexpr size_t kLargeObjectAlignment = kPageSize; 37 38 // Garbage collector constants. 39 static constexpr bool kMovingCollector = true; 40 static constexpr bool kMarkCompactSupport = false && kMovingCollector; 41 // True if we allow moving classes. 42 static constexpr bool kMovingClasses = !kMarkCompactSupport; 43 // When using the Concurrent Copying (CC) collector, if 44 // `ART_USE_GENERATIONAL_CC` is true, enable generational collection by default, 45 // i.e. use sticky-bit CC for minor collections and (full) CC for major 46 // collections. 47 // This default value can be overridden with the runtime option 48 // `-Xgc:[no]generational_cc`. 49 // 50 // TODO(b/67628039): Consider either: 51 // - renaming this to a better descriptive name (e.g. 52 // `ART_USE_GENERATIONAL_CC_BY_DEFAULT`); or 53 // - removing `ART_USE_GENERATIONAL_CC` and having a fixed default value. 54 // Any of these changes will require adjusting users of this preprocessor 55 // directive and the corresponding build system environment variable (e.g. in 56 // ART's continuous testing). 57 #ifdef ART_USE_GENERATIONAL_CC 58 static constexpr bool kEnableGenerationalCCByDefault = true; 59 #else 60 static constexpr bool kEnableGenerationalCCByDefault = false; 61 #endif 62 63 // If true, enable the tlab allocator by default. 64 #ifdef ART_USE_TLAB 65 static constexpr bool kUseTlab = true; 66 #else 67 static constexpr bool kUseTlab = false; 68 #endif 69 70 // Kinds of tracing clocks. 71 enum class TraceClockSource { 72 kThreadCpu, 73 kWall, 74 kDual, // Both wall and thread CPU clocks. 75 }; 76 77 #if defined(__linux__) 78 static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kDual; 79 #else 80 static constexpr TraceClockSource kDefaultTraceClockSource = TraceClockSource::kWall; 81 #endif 82 83 static constexpr bool kDefaultMustRelocate = true; 84 85 // Size of a heap reference. 86 static constexpr size_t kHeapReferenceSize = sizeof(uint32_t); 87 88 } // namespace art 89 90 #endif // ART_RUNTIME_RUNTIME_GLOBALS_H_ 91
