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 <vector> 22 #include "llvm/ADT/Triple.h" 23 #include "llvm/Support/DataTypes.h" 24 25 namespace llvm { 26 class raw_ostream; 27 class StringRef; 28 29 //===----------------------------------------------------------------------===// 30 /// 31 /// SubtargetFeatureKV - Used to provide key value pairs for feature and 32 /// CPU bit flags. 33 // 34 struct SubtargetFeatureKV { 35 const char *Key; // K-V key string 36 const char *Desc; // Help descriptor 37 uint64_t Value; // K-V integer value 38 uint64_t Implies; // K-V bit mask 39 40 // Compare routine for std binary search 41 bool operator<(const SubtargetFeatureKV &S) const { 42 return strcmp(Key, S.Key) < 0; 43 } 44 }; 45 46 //===----------------------------------------------------------------------===// 47 /// 48 /// SubtargetInfoKV - Used to provide key value pairs for CPU and arbitrary 49 /// pointers. 50 // 51 struct SubtargetInfoKV { 52 const char *Key; // K-V key string 53 void *Value; // K-V pointer value 54 55 // Compare routine for std binary search 56 bool operator<(const SubtargetInfoKV &S) const { 57 return strcmp(Key, S.Key) < 0; 58 } 59 }; 60 61 //===----------------------------------------------------------------------===// 62 /// 63 /// SubtargetFeatures - Manages the enabling and disabling of subtarget 64 /// specific features. Features are encoded as a string of the form 65 /// "cpu,+attr1,+attr2,-attr3,...,+attrN" 66 /// A comma separates each feature from the next (all lowercase.) 67 /// The first feature is always the CPU subtype (eg. pentiumm). If the CPU 68 /// value is "generic" then the CPU subtype should be generic for the target. 69 /// Each of the remaining features is prefixed with + or - indicating whether 70 /// that feature should be enabled or disabled contrary to the cpu 71 /// specification. 72 /// 73 74 class SubtargetFeatures { 75 std::vector<std::string> Features; // Subtarget features as a vector 76 public: 77 explicit SubtargetFeatures(const StringRef Initial = ""); 78 79 /// Features string accessors. 80 std::string getString() const; 81 82 /// Adding Features. 83 void AddFeature(const StringRef String, bool IsEnabled = true); 84 85 /// ToggleFeature - Toggle a feature and returns the newly updated feature 86 /// bits. 87 uint64_t ToggleFeature(uint64_t Bits, const StringRef String, 88 const SubtargetFeatureKV *FeatureTable, 89 size_t FeatureTableSize); 90 91 /// Get feature bits of a CPU. 92 uint64_t getFeatureBits(const StringRef CPU, 93 const SubtargetFeatureKV *CPUTable, 94 size_t CPUTableSize, 95 const SubtargetFeatureKV *FeatureTable, 96 size_t FeatureTableSize); 97 98 /// Get scheduling itinerary of a CPU. 99 void *getItinerary(const StringRef CPU, 100 const SubtargetInfoKV *Table, size_t TableSize); 101 102 /// Print feature string. 103 void print(raw_ostream &OS) const; 104 105 // Dump feature info. 106 void dump() const; 107 108 /// Retrieve a formatted string of the default features for the specified 109 /// target triple. 110 void getDefaultSubtargetFeatures(const Triple& Triple); 111 }; 112 113 } // End namespace llvm 114 115 #endif 116
