LLVM  3.7.0
SubtargetFeature.h
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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 
26 namespace 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.
33 const unsigned MAX_SUBTARGET_FEATURES = 64;
34 class FeatureBitset : public std::bitset<MAX_SUBTARGET_FEATURES> {
35 public:
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 //
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 //
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 
91  std::vector<std::string> Features; // Subtarget features as a vector
92 public:
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.
104  ArrayRef<SubtargetFeatureKV> FeatureTable);
105 
106  /// Apply the feature flag and return the newly updated feature bits.
108  ArrayRef<SubtargetFeatureKV> FeatureTable);
109 
110  /// Get feature bits of a CPU.
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.
123 };
124 
125 } // End namespace llvm
126 
127 #endif
const unsigned MAX_SUBTARGET_FEATURES
void getDefaultSubtargetFeatures(const Triple &Triple)
Adds the default features for the specified target triple.
bool operator<(StringRef S) const
SubtargetInfoKV - Used to provide key value pairs for CPU and arbitrary pointers. ...
FeatureBitset ApplyFeatureFlag(FeatureBitset Bits, StringRef Feature, ArrayRef< SubtargetFeatureKV > FeatureTable)
Apply the feature flag and return the newly updated feature bits.
void AddFeature(StringRef String, bool Enable=true)
Adding Features.
SubtargetFeatureKV - Used to provide key value pairs for feature and CPU bit flags.
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: ArrayRef.h:31
void dump() const
dump - Dump feature info.
std::string getString() const
Features string accessors.
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:44
bool operator<(StringRef S) const
FeatureBitset(const bitset< MAX_SUBTARGET_FEATURES > &B)
SubtargetFeatures(StringRef Initial="")
SubtargetFeatures - Manages the enabling and disabling of subtarget specific features.
FeatureBitset ToggleFeature(FeatureBitset Bits, StringRef String, ArrayRef< SubtargetFeatureKV > FeatureTable)
ToggleFeature - Toggle a feature and returns the newly updated feature bits.
#define I(x, y, z)
Definition: MD5.cpp:54
FeatureBitset(std::initializer_list< unsigned > Init)
void print(raw_ostream &OS) const
Print feature string.
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:38
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:40
FeatureBitset getFeatureBits(StringRef CPU, ArrayRef< SubtargetFeatureKV > CPUTable, ArrayRef< SubtargetFeatureKV > FeatureTable)
Get feature bits of a CPU.