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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 <iosfwd>
#include <memory>
#include <vector>
#include "arch/instruction_set.h"
#include "base/macros.h"
namespace art {
class ArmInstructionSetFeatures;
class Arm64InstructionSetFeatures;
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();
// Check if run-time detection of instruction set features is supported.
//
// Return: true - if run-time detection is supported on a target device.
// false - otherwise
static bool IsRuntimeDetectionSupported() {
return FromRuntimeDetection() != nullptr;
}
// Use run-time detection to get instruction set features.
//
// Return: a set of detected features or nullptr if runtime detection is not
// supported on a target.
static std::unique_ptr<const InstructionSetFeatures> FromRuntimeDetection();
// 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();
// Use external cpu_features library.
static std::unique_ptr<const InstructionSetFeatures> FromCpuFeatures();
// 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 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;
// Add run-time detected architecture specific features in sub-classes.
virtual std::unique_ptr<const InstructionSetFeatures>
AddRuntimeDetectedFeatures(const InstructionSetFeatures *features ATTRIBUTE_UNUSED) const;
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_