| //===- llvm/MC/SubtargetFeature.h - CPU characteristics ---------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| /// \file Defines and manages user or tool specified CPU characteristics. |
| /// The intent is to be able to package specific features that should or should |
| /// not be used on a specific target processor. A tool, such as llc, could, as |
| /// as example, gather chip info from the command line, a long with features |
| /// that should be used on that chip. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_MC_SUBTARGETFEATURE_H |
| #define LLVM_MC_SUBTARGETFEATURE_H |
| |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/Support/MathExtras.h" |
| #include <array> |
| #include <bitset> |
| #include <initializer_list> |
| #include <string> |
| #include <vector> |
| |
| namespace llvm { |
| |
| class raw_ostream; |
| class Triple; |
| |
| const unsigned MAX_SUBTARGET_WORDS = 3; |
| const unsigned MAX_SUBTARGET_FEATURES = MAX_SUBTARGET_WORDS * 64; |
| |
| /// Container class for subtarget features. |
| /// This is a constexpr reimplementation of a subset of std::bitset. It would be |
| /// nice to use std::bitset directly, but it doesn't support constant |
| /// initialization. |
| class FeatureBitset { |
| static_assert((MAX_SUBTARGET_FEATURES % 64) == 0, |
| "Should be a multiple of 64!"); |
| // This cannot be a std::array, operator[] is not constexpr until C++17. |
| uint64_t Bits[MAX_SUBTARGET_WORDS] = {}; |
| |
| protected: |
| constexpr FeatureBitset(const std::array<uint64_t, MAX_SUBTARGET_WORDS> &B) { |
| for (unsigned I = 0; I != B.size(); ++I) |
| Bits[I] = B[I]; |
| } |
| |
| public: |
| constexpr FeatureBitset() = default; |
| constexpr FeatureBitset(std::initializer_list<unsigned> Init) { |
| for (auto I : Init) |
| set(I); |
| } |
| |
| FeatureBitset &set() { |
| std::fill(std::begin(Bits), std::end(Bits), -1ULL); |
| return *this; |
| } |
| |
| constexpr FeatureBitset &set(unsigned I) { |
| // GCC <6.2 crashes if this is written in a single statement. |
| uint64_t NewBits = Bits[I / 64] | (uint64_t(1) << (I % 64)); |
| Bits[I / 64] = NewBits; |
| return *this; |
| } |
| |
| constexpr FeatureBitset &reset(unsigned I) { |
| // GCC <6.2 crashes if this is written in a single statement. |
| uint64_t NewBits = Bits[I / 64] & ~(uint64_t(1) << (I % 64)); |
| Bits[I / 64] = NewBits; |
| return *this; |
| } |
| |
| constexpr FeatureBitset &flip(unsigned I) { |
| // GCC <6.2 crashes if this is written in a single statement. |
| uint64_t NewBits = Bits[I / 64] ^ (uint64_t(1) << (I % 64)); |
| Bits[I / 64] = NewBits; |
| return *this; |
| } |
| |
| constexpr bool operator[](unsigned I) const { |
| uint64_t Mask = uint64_t(1) << (I % 64); |
| return (Bits[I / 64] & Mask) != 0; |
| } |
| |
| constexpr bool test(unsigned I) const { return (*this)[I]; } |
| |
| constexpr size_t size() const { return MAX_SUBTARGET_FEATURES; } |
| |
| bool any() const { |
| return llvm::any_of(Bits, [](uint64_t I) { return I != 0; }); |
| } |
| bool none() const { return !any(); } |
| size_t count() const { |
| size_t Count = 0; |
| for (auto B : Bits) |
| Count += countPopulation(B); |
| return Count; |
| } |
| |
| constexpr FeatureBitset &operator^=(const FeatureBitset &RHS) { |
| for (unsigned I = 0, E = array_lengthof(Bits); I != E; ++I) { |
| Bits[I] ^= RHS.Bits[I]; |
| } |
| return *this; |
| } |
| constexpr FeatureBitset operator^(const FeatureBitset &RHS) const { |
| FeatureBitset Result = *this; |
| Result ^= RHS; |
| return Result; |
| } |
| |
| constexpr FeatureBitset &operator&=(const FeatureBitset &RHS) { |
| for (unsigned I = 0, E = array_lengthof(Bits); I != E; ++I) { |
| Bits[I] &= RHS.Bits[I]; |
| } |
| return *this; |
| } |
| constexpr FeatureBitset operator&(const FeatureBitset &RHS) const { |
| FeatureBitset Result = *this; |
| Result &= RHS; |
| return Result; |
| } |
| |
| constexpr FeatureBitset &operator|=(const FeatureBitset &RHS) { |
| for (unsigned I = 0, E = array_lengthof(Bits); I != E; ++I) { |
| Bits[I] |= RHS.Bits[I]; |
| } |
| return *this; |
| } |
| constexpr FeatureBitset operator|(const FeatureBitset &RHS) const { |
| FeatureBitset Result = *this; |
| Result |= RHS; |
| return Result; |
| } |
| |
| constexpr FeatureBitset operator~() const { |
| FeatureBitset Result = *this; |
| for (auto &B : Result.Bits) |
| B = ~B; |
| return Result; |
| } |
| |
| bool operator==(const FeatureBitset &RHS) const { |
| return std::equal(std::begin(Bits), std::end(Bits), std::begin(RHS.Bits)); |
| } |
| |
| bool operator!=(const FeatureBitset &RHS) const { return !(*this == RHS); } |
| |
| bool operator < (const FeatureBitset &Other) const { |
| for (unsigned I = 0, E = size(); I != E; ++I) { |
| bool LHS = test(I), RHS = Other.test(I); |
| if (LHS != RHS) |
| return LHS < RHS; |
| } |
| return false; |
| } |
| }; |
| |
| /// Class used to store the subtarget bits in the tables created by tablegen. |
| class FeatureBitArray : public FeatureBitset { |
| public: |
| constexpr FeatureBitArray(const std::array<uint64_t, MAX_SUBTARGET_WORDS> &B) |
| : FeatureBitset(B) {} |
| |
| const FeatureBitset &getAsBitset() const { return *this; } |
| }; |
| |
| //===----------------------------------------------------------------------===// |
| |
| /// Manages the enabling and disabling of subtarget specific features. |
| /// |
| /// Features are encoded as a string of the form |
| /// "+attr1,+attr2,-attr3,...,+attrN" |
| /// A comma separates each feature from the next (all lowercase.) |
| /// Each of the remaining features is prefixed with + or - indicating whether |
| /// that feature should be enabled or disabled contrary to the cpu |
| /// specification. |
| class SubtargetFeatures { |
| std::vector<std::string> Features; ///< Subtarget features as a vector |
| |
| public: |
| explicit SubtargetFeatures(StringRef Initial = ""); |
| |
| /// Returns features as a string. |
| std::string getString() const; |
| |
| /// Adds Features. |
| void AddFeature(StringRef String, bool Enable = true); |
| |
| /// Returns the vector of individual subtarget features. |
| const std::vector<std::string> &getFeatures() const { return Features; } |
| |
| /// Prints feature string. |
| void print(raw_ostream &OS) const; |
| |
| // Dumps feature info. |
| void dump() const; |
| |
| /// Adds the default features for the specified target triple. |
| void getDefaultSubtargetFeatures(const Triple& Triple); |
| |
| /// Determine if a feature has a flag; '+' or '-' |
| static bool hasFlag(StringRef Feature) { |
| assert(!Feature.empty() && "Empty string"); |
| // Get first character |
| char Ch = Feature[0]; |
| // Check if first character is '+' or '-' flag |
| return Ch == '+' || Ch =='-'; |
| } |
| |
| /// Return string stripped of flag. |
| static std::string StripFlag(StringRef Feature) { |
| return hasFlag(Feature) ? Feature.substr(1) : Feature; |
| } |
| |
| /// Return true if enable flag; '+'. |
| static inline bool isEnabled(StringRef Feature) { |
| assert(!Feature.empty() && "Empty string"); |
| // Get first character |
| char Ch = Feature[0]; |
| // Check if first character is '+' for enabled |
| return Ch == '+'; |
| } |
| |
| /// Splits a string of comma separated items in to a vector of strings. |
| static void Split(std::vector<std::string> &V, StringRef S); |
| }; |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_MC_SUBTARGETFEATURE_H |