gcc/rust/typecheck/rust-tyty-region.h

   1 #ifndef RUST_TYTY_REGION_H
   2 #define RUST_TYTY_REGION_H
   3
   4 namespace Rust {
   5 namespace TyTy {
   6
   7 class Region
   8 {
   9   enum Variant : uint8_t
  10   {
  11     UNRESOLVED,
  12     STATIC,
  13     EARLY_BOUND,
  14     LATE_BOUND,
  15     NAMED,
  16     ANONYMOUS,
  17     ERASED,
  18   };
  19
  20   uint32_t index;
  21   uint16_t debruijn_index;
  22   Variant variant;
  23
  24 public:
  25   Region () : Region (UNRESOLVED) {}
  26   Region (const Region &other)
  27     : index (other.index), debruijn_index (other.debruijn_index),
  28       variant (other.variant)
  29   {}
  30   Region (Region &&other) noexcept
  31     : index (other.index), debruijn_index (other.debruijn_index),
  32       variant (other.variant)
  33   {}
  34   Region &operator= (const Region &other)
  35   {
  36     if (this == &other)
  37       return *this;
  38     index = other.index;
  39     debruijn_index = other.debruijn_index;
  40     variant = other.variant;
  41     return *this;
  42   }
  43   Region &operator= (Region &&other) noexcept
  44   {
  45     if (this == &other)
  46       return *this;
  47     index = other.index;
  48     debruijn_index = other.debruijn_index;
  49     variant = other.variant;
  50     return *this;
  51   }
  52
  53   static Region make_static () { return Region (STATIC); }
  54   static Region make_early_bound (uint32_t index)
  55   {
  56     return Region (EARLY_BOUND, index);
  57   }
  58   static Region make_late_bound (uint32_t index, uint16_t debruijn_index)
  59   {
  60     return Region (LATE_BOUND, index, debruijn_index);
  61   }
  62   static Region make_named (uint32_t index) { return Region (NAMED, index); }
  63   static Region make_anonymous () { return Region (ANONYMOUS); }
  64   static Region make_erased () { return Region (ERASED); }
  65
  66   size_t get_index () const { return index; }
  67
  68   bool is_static () const { return variant == STATIC; }
  69   bool is_early_bound () const { return variant == EARLY_BOUND; }
  70   bool is_late_bound () const { return variant == LATE_BOUND; }
  71   bool is_named () const { return variant == NAMED; }
  72   bool is_anonymous () const { return variant == ANONYMOUS; }
  73
  74   void shift_down () { debruijn_index++; }
  75
  76   WARN_UNUSED_RESULT std::string as_string () const
  77   {
  78     switch (variant)
  79       {
  80       case UNRESOLVED:
  81         return "'unresolved";
  82       case STATIC:
  83         return "'static";
  84       case EARLY_BOUND:
  85         return "'early(" + std::to_string (index) + ")";
  86       case LATE_BOUND:
  87         return "'late(" + std::to_string (debruijn_index) + ", "
  88                + std::to_string (index) + ")";
  89       case NAMED:
  90         return "'named(" + std::to_string (index) + "";
  91       case ANONYMOUS:
  92         return "'_";
  93       case ERASED:
  94         return "'erased";
  95       }
  96
  97     rust_unreachable ();
  98   }
  99
 100 private:
 101   explicit Region (Variant variant, uint32_t index = 0,
 102                    uint16_t debruijn_index = 0)
 103     : index (index), debruijn_index (debruijn_index), variant (variant)
 104   {}
 105 };
 106
 107 } // namespace TyTy
 108 } // namespace Rust
 109
 110 #endif // RUST_TYTY_REGION_H