1//===-- llvm/MC/SubtargetFeature.h - CPU characteristics --------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines and manages user or tool specified CPU characteristics. 11// The intent is to be able to package specific features that should or should 12// not be used on a specific target processor. A tool, such as llc, could, as 13// as example, gather chip info from the command line, a long with features 14// that should be used on that chip. 15// 16//===----------------------------------------------------------------------===// 17 18#ifndef LLVM_MC_SUBTARGETFEATURE_H 19#define LLVM_MC_SUBTARGETFEATURE_H 20 21#include "llvm/ADT/ArrayRef.h" 22#include "llvm/ADT/Triple.h" 23#include "llvm/Support/DataTypes.h" 24#include <bitset> 25 26namespace llvm { 27 class raw_ostream; 28 class StringRef; 29 30// A container class for subtarget features. 31// This is convenient because std::bitset does not have a constructor 32// with an initializer list of set bits. 33const unsigned MAX_SUBTARGET_FEATURES = 128; 34class FeatureBitset : public std::bitset<MAX_SUBTARGET_FEATURES> { 35public: 36 // Cannot inherit constructors because it's not supported by VC++.. 37 FeatureBitset() : bitset() {} 38 39 FeatureBitset(const bitset<MAX_SUBTARGET_FEATURES>& B) : bitset(B) {} 40 41 FeatureBitset(std::initializer_list<unsigned> Init) : bitset() { 42 for (auto I = Init.begin() , E = Init.end(); I != E; ++I) 43 set(*I); 44 } 45}; 46 47//===----------------------------------------------------------------------===// 48/// 49/// SubtargetFeatureKV - Used to provide key value pairs for feature and 50/// CPU bit flags. 51// 52struct SubtargetFeatureKV { 53 const char *Key; // K-V key string 54 const char *Desc; // Help descriptor 55 FeatureBitset Value; // K-V integer value 56 FeatureBitset Implies; // K-V bit mask 57 58 // Compare routine for std::lower_bound 59 bool operator<(StringRef S) const { 60 return StringRef(Key) < S; 61 } 62}; 63 64//===----------------------------------------------------------------------===// 65/// 66/// SubtargetInfoKV - Used to provide key value pairs for CPU and arbitrary 67/// pointers. 68// 69struct SubtargetInfoKV { 70 const char *Key; // K-V key string 71 const void *Value; // K-V pointer value 72 73 // Compare routine for std::lower_bound 74 bool operator<(StringRef S) const { 75 return StringRef(Key) < S; 76 } 77}; 78 79//===----------------------------------------------------------------------===// 80/// 81/// SubtargetFeatures - Manages the enabling and disabling of subtarget 82/// specific features. Features are encoded as a string of the form 83/// "+attr1,+attr2,-attr3,...,+attrN" 84/// A comma separates each feature from the next (all lowercase.) 85/// Each of the remaining features is prefixed with + or - indicating whether 86/// that feature should be enabled or disabled contrary to the cpu 87/// specification. 88/// 89 90class SubtargetFeatures { 91 std::vector<std::string> Features; // Subtarget features as a vector 92public: 93 explicit SubtargetFeatures(StringRef Initial = ""); 94 95 /// Features string accessors. 96 std::string getString() const; 97 98 /// Adding Features. 99 void AddFeature(StringRef String, bool Enable = true); 100 101 /// ToggleFeature - Toggle a feature and returns the newly updated feature 102 /// bits. 103 FeatureBitset ToggleFeature(FeatureBitset Bits, StringRef String, 104 ArrayRef<SubtargetFeatureKV> FeatureTable); 105 106 /// Apply the feature flag and return the newly updated feature bits. 107 FeatureBitset ApplyFeatureFlag(FeatureBitset Bits, StringRef Feature, 108 ArrayRef<SubtargetFeatureKV> FeatureTable); 109 110 /// Get feature bits of a CPU. 111 FeatureBitset getFeatureBits(StringRef CPU, 112 ArrayRef<SubtargetFeatureKV> CPUTable, 113 ArrayRef<SubtargetFeatureKV> FeatureTable); 114 115 /// Print feature string. 116 void print(raw_ostream &OS) const; 117 118 // Dump feature info. 119 void dump() const; 120 121 /// Adds the default features for the specified target triple. 122 void getDefaultSubtargetFeatures(const Triple& Triple); 123}; 124 125} // End namespace llvm 126 127#endif 128