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
25namespace 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//
34struct 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::lower_bound
41  bool operator<(StringRef S) const {
42    return StringRef(Key) < S;
43  }
44};
45
46//===----------------------------------------------------------------------===//
47///
48/// SubtargetInfoKV - Used to provide key value pairs for CPU and arbitrary
49/// pointers.
50//
51struct SubtargetInfoKV {
52  const char *Key;                      // K-V key string
53  const void *Value;                    // K-V pointer value
54
55  // Compare routine for std::lower_bound
56  bool operator<(StringRef S) const {
57    return StringRef(Key) < S;
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///   "+attr1,+attr2,-attr3,...,+attrN"
66/// A comma separates each feature from the next (all lowercase.)
67/// Each of the remaining features is prefixed with + or - indicating whether
68/// that feature should be enabled or disabled contrary to the cpu
69/// specification.
70///
71
72class SubtargetFeatures {
73  std::vector<std::string> Features;    // Subtarget features as a vector
74public:
75  explicit SubtargetFeatures(const StringRef Initial = "");
76
77  /// Features string accessors.
78  std::string getString() const;
79
80  /// Adding Features.
81  void AddFeature(const StringRef String);
82
83  /// ToggleFeature - Toggle a feature and returns the newly updated feature
84  /// bits.
85  uint64_t ToggleFeature(uint64_t Bits, const StringRef String,
86                         ArrayRef<SubtargetFeatureKV> FeatureTable);
87
88  /// Get feature bits of a CPU.
89  uint64_t getFeatureBits(const StringRef CPU,
90                          ArrayRef<SubtargetFeatureKV> CPUTable,
91                          ArrayRef<SubtargetFeatureKV> FeatureTable);
92
93  /// Print feature string.
94  void print(raw_ostream &OS) const;
95
96  // Dump feature info.
97  void dump() const;
98
99  /// Adds the default features for the specified target triple.
100  void getDefaultSubtargetFeatures(const Triple& Triple);
101};
102
103} // End namespace llvm
104
105#endif
106