| //===- 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 <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 convenient because std::bitset does not have a constructor |
| /// with an initializer list of set bits. |
| class FeatureBitset : public std::bitset<MAX_SUBTARGET_FEATURES> { |
| public: |
| // Cannot inherit constructors because it's not supported by VC++.. |
| FeatureBitset() = default; |
| |
| FeatureBitset(const bitset<MAX_SUBTARGET_FEATURES>& B) : bitset(B) {} |
| |
| FeatureBitset(std::initializer_list<unsigned> Init) { |
| for (auto I : Init) |
| set(I); |
| } |
| |
| 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. |
| /// The std::initializer_list constructor of FeatureBitset can't be done at |
| /// compile time and requires a static constructor to run at startup. |
| class FeatureBitArray { |
| std::array<uint64_t, MAX_SUBTARGET_WORDS> Bits; |
| |
| public: |
| constexpr FeatureBitArray(const std::array<uint64_t, MAX_SUBTARGET_WORDS> &B) |
| : Bits(B) {} |
| |
| FeatureBitset getAsBitset() const { |
| FeatureBitset Result; |
| |
| for (unsigned i = 0, e = Bits.size(); i != e; ++i) |
| Result |= FeatureBitset(Bits[i]) << (64 * i); |
| |
| return Result; |
| } |
| }; |
| |
| //===----------------------------------------------------------------------===// |
| |
| /// 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 |