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_ARCH_INSTRUCTION_SET_FEATURES_H_ 18 #define ART_RUNTIME_ARCH_INSTRUCTION_SET_FEATURES_H_ 19 20 #include <iosfwd> 21 #include <memory> 22 #include <vector> 23 24 #include "arch/instruction_set.h" 25 #include "base/macros.h" 26 27 namespace art { 28 29 class ArmInstructionSetFeatures; 30 class Arm64InstructionSetFeatures; 31 class MipsInstructionSetFeatures; 32 class Mips64InstructionSetFeatures; 33 class X86InstructionSetFeatures; 34 class X86_64InstructionSetFeatures; 35 36 // Abstraction used to describe features of a different instruction sets. 37 class InstructionSetFeatures { 38 public: 39 // Process a CPU variant string for the given ISA and create an InstructionSetFeatures. 40 static std::unique_ptr<const InstructionSetFeatures> FromVariant(InstructionSet isa, 41 const std::string& variant, 42 std::string* error_msg); 43 44 // Parse a bitmap for the given isa and create an InstructionSetFeatures. 45 static std::unique_ptr<const InstructionSetFeatures> FromBitmap(InstructionSet isa, 46 uint32_t bitmap); 47 48 // Turn C pre-processor #defines into the equivalent instruction set features for kRuntimeISA. 49 static std::unique_ptr<const InstructionSetFeatures> FromCppDefines(); 50 51 // Check if run-time detection of instruction set features is supported. 52 // 53 // Return: true - if run-time detection is supported on a target device. 54 // false - otherwise IsRuntimeDetectionSupported()55 static bool IsRuntimeDetectionSupported() { 56 return FromRuntimeDetection() != nullptr; 57 } 58 59 // Use run-time detection to get instruction set features. 60 // 61 // Return: a set of detected features or nullptr if runtime detection is not 62 // supported on a target. 63 static std::unique_ptr<const InstructionSetFeatures> FromRuntimeDetection(); 64 65 // Process /proc/cpuinfo and use kRuntimeISA to produce InstructionSetFeatures. 66 static std::unique_ptr<const InstructionSetFeatures> FromCpuInfo(); 67 68 // Process the auxiliary vector AT_HWCAP entry and use kRuntimeISA to produce 69 // InstructionSetFeatures. 70 static std::unique_ptr<const InstructionSetFeatures> FromHwcap(); 71 72 // Use assembly tests of the current runtime (ie kRuntimeISA) to determine the 73 // InstructionSetFeatures. This works around kernel bugs in AT_HWCAP and /proc/cpuinfo. 74 static std::unique_ptr<const InstructionSetFeatures> FromAssembly(); 75 76 // Parse a string of the form "div,-atomic_ldrd_strd" adding and removing these features to 77 // create a new InstructionSetFeatures. 78 std::unique_ptr<const InstructionSetFeatures> AddFeaturesFromString( 79 const std::string& feature_list, std::string* error_msg) const WARN_UNUSED; 80 81 // Are these features the same as the other given features? 82 virtual bool Equals(const InstructionSetFeatures* other) const = 0; 83 84 // For testing purposes we want to make sure that the system we run on has at 85 // least the options we claim it has. In this cases Equals() does not 86 // suffice and will cause the test to fail, since the runtime cpu feature 87 // detection claims more capabilities then statically specified from the 88 // build system. 89 // 90 // A good example of this is the armv8 ART test target that declares 91 // "CPU_VARIANT=generic". If the generic target is specified and the code 92 // is run on a platform with enhanced capabilities, the 93 // instruction_set_features test will fail if we resort to using Equals() 94 // between statically defined cpu features and runtime cpu features. 95 // 96 // For now we default this to Equals() in case the architecture does not 97 // provide it. HasAtLeast(const InstructionSetFeatures * other)98 virtual bool HasAtLeast(const InstructionSetFeatures* other) const { 99 return Equals(other); 100 } 101 102 // Return the ISA these features relate to. 103 virtual InstructionSet GetInstructionSet() const = 0; 104 105 // Return a bitmap that represents the features. ISA specific. 106 virtual uint32_t AsBitmap() const = 0; 107 108 // Return a string of the form "div,lpae" or "none". 109 virtual std::string GetFeatureString() const = 0; 110 111 // Down cast this ArmInstructionFeatures. 112 const ArmInstructionSetFeatures* AsArmInstructionSetFeatures() const; 113 114 // Down cast this Arm64InstructionFeatures. 115 const Arm64InstructionSetFeatures* AsArm64InstructionSetFeatures() const; 116 117 // Down cast this MipsInstructionFeatures. 118 const MipsInstructionSetFeatures* AsMipsInstructionSetFeatures() const; 119 120 // Down cast this Mips64InstructionFeatures. 121 const Mips64InstructionSetFeatures* AsMips64InstructionSetFeatures() const; 122 123 // Down cast this X86InstructionFeatures. 124 const X86InstructionSetFeatures* AsX86InstructionSetFeatures() const; 125 126 // Down cast this X86_64InstructionFeatures. 127 const X86_64InstructionSetFeatures* AsX86_64InstructionSetFeatures() const; 128 ~InstructionSetFeatures()129 virtual ~InstructionSetFeatures() {} 130 131 protected: InstructionSetFeatures()132 InstructionSetFeatures() {} 133 134 // Returns true if variant appears in the array variants. 135 static bool FindVariantInArray(const char* const variants[], size_t num_variants, 136 const std::string& variant); 137 138 // Add architecture specific features in sub-classes. 139 virtual std::unique_ptr<const InstructionSetFeatures> 140 AddFeaturesFromSplitString(const std::vector<std::string>& features, 141 std::string* error_msg) const = 0; 142 143 // Add run-time detected architecture specific features in sub-classes. 144 virtual std::unique_ptr<const InstructionSetFeatures> 145 AddRuntimeDetectedFeatures(const InstructionSetFeatures *features ATTRIBUTE_UNUSED) const; 146 147 private: 148 DISALLOW_COPY_AND_ASSIGN(InstructionSetFeatures); 149 }; 150 std::ostream& operator<<(std::ostream& os, const InstructionSetFeatures& rhs); 151 152 } // namespace art 153 154 #endif // ART_RUNTIME_ARCH_INSTRUCTION_SET_FEATURES_H_ 155