include/llvm/Target/SubtargetFeature.h

   1 //===-- llvm/Target/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_TARGET_SUBTARGETFEATURE_H
  19 #define LLVM_TARGET_SUBTARGETFEATURE_H
  20
  21 #include <string>
  22 #include <vector>
  23 #include <cstring>
  24 #include "llvm/Support/DataTypes.h"
  25
  26 namespace llvm {
  27   class raw_ostream;
  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   uint32_t Value;                       // K-V integer value
  38   uint32_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 std::string &Initial = std::string());
  78
  79   /// Features string accessors.
  80   std::string getString() const;
  81   void setString(const std::string &Initial);
  82
  83   /// Set the CPU string.  Replaces previous setting.  Setting to "" clears CPU.
  84   void setCPU(const std::string &String);
  85
  86   /// Setting CPU string only if no string is set.
  87   void setCPUIfNone(const std::string &String);
  88
  89   /// Returns current CPU string.
  90   const std::string & getCPU() const;
  91
  92   /// Adding Features.
  93   void AddFeature(const std::string &String, bool IsEnabled = true);
  94
  95   /// Get feature bits.
  96   uint32_t getBits(const SubtargetFeatureKV *CPUTable,
  97                          size_t CPUTableSize,
  98                    const SubtargetFeatureKV *FeatureTable,
  99                          size_t FeatureTableSize);
 100
 101   /// Get info pointer
 102   void *getInfo(const SubtargetInfoKV *Table, size_t TableSize);
 103
 104   /// Print feature string.
 105   void print(raw_ostream &OS) const;
 106
 107   // Dump feature info.
 108   void dump() const;
 109 };
 110
 111 } // End namespace llvm
 112
 113 #endif