upload android base code part3

android/art/runtime/arch/instruction_set_features.h

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+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_ARCH_INSTRUCTION_SET_FEATURES_H_
+#define ART_RUNTIME_ARCH_INSTRUCTION_SET_FEATURES_H_
+
+#include <memory>
+#include <ostream>
+#include <vector>
+
+#include "base/macros.h"
+#include "instruction_set.h"
+
+namespace art {
+
+class ArmInstructionSetFeatures;
+class Arm64InstructionSetFeatures;
+class MipsInstructionSetFeatures;
+class Mips64InstructionSetFeatures;
+class X86InstructionSetFeatures;
+class X86_64InstructionSetFeatures;
+
+// Abstraction used to describe features of a different instruction sets.
+class InstructionSetFeatures {
+ public:
+  // Process a CPU variant string for the given ISA and create an InstructionSetFeatures.
+  static std::unique_ptr<const InstructionSetFeatures> FromVariant(InstructionSet isa,
+                                                                   const std::string& variant,
+                                                                   std::string* error_msg);
+
+  // Parse a bitmap for the given isa and create an InstructionSetFeatures.
+  static std::unique_ptr<const InstructionSetFeatures> FromBitmap(InstructionSet isa,
+                                                                  uint32_t bitmap);
+
+  // Turn C pre-processor #defines into the equivalent instruction set features for kRuntimeISA.
+  static std::unique_ptr<const InstructionSetFeatures> FromCppDefines();
+
+  // Process /proc/cpuinfo and use kRuntimeISA to produce InstructionSetFeatures.
+  static std::unique_ptr<const InstructionSetFeatures> FromCpuInfo();
+
+  // Process the auxiliary vector AT_HWCAP entry and use kRuntimeISA to produce
+  // InstructionSetFeatures.
+  static std::unique_ptr<const InstructionSetFeatures> FromHwcap();
+
+  // Use assembly tests of the current runtime (ie kRuntimeISA) to determine the
+  // InstructionSetFeatures. This works around kernel bugs in AT_HWCAP and /proc/cpuinfo.
+  static std::unique_ptr<const InstructionSetFeatures> FromAssembly();
+
+  // Parse a string of the form "div,-atomic_ldrd_strd" adding and removing these features to
+  // create a new InstructionSetFeatures.
+  std::unique_ptr<const InstructionSetFeatures> AddFeaturesFromString(
+      const std::string& feature_list, std::string* error_msg) const WARN_UNUSED;
+
+  // Are these features the same as the other given features?
+  virtual bool Equals(const InstructionSetFeatures* other) const = 0;
+
+  // For testing purposes we want to make sure that the system we run on has at
+  // least the options we claim it has. In this cases Equals() does not
+  // suffice and will cause the test to fail, since the runtime cpu feature
+  // detection claims more capabilities then statically specified from the
+  // build system.
+  //
+  // A good example of this is the armv8 ART test target that declares
+  // "CPU_VARIANT=generic". If the generic target is specified and the code
+  // is run on a platform with enhanced capabilities, the
+  // instruction_set_features test will fail if we resort to using Equals()
+  // between statically defined cpu features and runtime cpu features.
+  //
+  // For now we default this to Equals() in case the architecture does not
+  // provide it.
+  virtual bool HasAtLeast(const InstructionSetFeatures* other) const {
+    return Equals(other);
+  }
+
+  // Return the ISA these features relate to.
+  virtual InstructionSet GetInstructionSet() const = 0;
+
+  // Return a bitmap that represents the features. ISA specific.
+  virtual uint32_t AsBitmap() const = 0;
+
+  // Return a string of the form "div,lpae" or "none".
+  virtual std::string GetFeatureString() const = 0;
+
+  // Down cast this ArmInstructionFeatures.
+  const ArmInstructionSetFeatures* AsArmInstructionSetFeatures() const;
+
+  // Down cast this Arm64InstructionFeatures.
+  const Arm64InstructionSetFeatures* AsArm64InstructionSetFeatures() const;
+
+  // Down cast this MipsInstructionFeatures.
+  const MipsInstructionSetFeatures* AsMipsInstructionSetFeatures() const;
+
+  // Down cast this Mips64InstructionFeatures.
+  const Mips64InstructionSetFeatures* AsMips64InstructionSetFeatures() const;
+
+  // Down cast this X86InstructionFeatures.
+  const X86InstructionSetFeatures* AsX86InstructionSetFeatures() const;
+
+  // Down cast this X86_64InstructionFeatures.
+  const X86_64InstructionSetFeatures* AsX86_64InstructionSetFeatures() const;
+
+  virtual ~InstructionSetFeatures() {}
+
+ protected:
+  InstructionSetFeatures() {}
+
+  // Returns true if variant appears in the array variants.
+  static bool FindVariantInArray(const char* const variants[], size_t num_variants,
+                                 const std::string& variant);
+
+  // Add architecture specific features in sub-classes.
+  virtual std::unique_ptr<const InstructionSetFeatures>
+      AddFeaturesFromSplitString(const std::vector<std::string>& features,
+                                 std::string* error_msg) const = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(InstructionSetFeatures);
+};
+std::ostream& operator<<(std::ostream& os, const InstructionSetFeatures& rhs);
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_ARCH_INSTRUCTION_SET_FEATURES_H_