gdb/arch/riscv.h

   1 /* Common target-dependent functionality for RISC-V
   2
   3    Copyright (C) 2018-2021 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef ARCH_RISCV_H
  21 #define ARCH_RISCV_H
  22
  23 #include "gdbsupport/tdesc.h"
  24
  25 /* The set of RISC-V architectural features that we track that impact how
  26    we configure the actual gdbarch instance.  We hold one of these in the
  27    gdbarch_tdep structure, and use it to distinguish between different
  28    RISC-V gdbarch instances.
  29
  30    The information in here ideally comes from the target description,
  31    however, if the target doesn't provide a target description then we will
  32    create a default target description by first populating one of these
  33    based on what we know about the binary being executed, and using that to
  34    drive default target description creation.  */
  35
  36 struct riscv_gdbarch_features
  37 {
  38   /* The size of the x-registers in bytes.  This is either 4 (RV32), 8
  39      (RV64), or 16 (RV128).  No other value is valid.  Initialise to the
  40      invalid 0 value so we can spot if one of these is used
  41      uninitialised.  */
  42   int xlen = 0;
  43
  44   /* The size of the f-registers in bytes.  This is either 4 (RV32), 8
  45      (RV64), or 16 (RV128).  This can also hold the value 0 to indicate
  46      that there are no f-registers.  No other value is valid.  */
  47   int flen = 0;
  48
  49   /* The size of the v-registers in bytes.  The value 0 indicates a target
  50      with no vector registers.  The minimum value for a standard compliant
  51      target should be 16, but GDB doesn't currently mind, and will accept
  52      any vector size.  */
  53   int vlen = 0;
  54
  55   /* When true this target is RV32E.  */
  56   bool embedded = false;
  57
  58   /* Equality operator.  */
  59   bool operator== (const struct riscv_gdbarch_features &rhs) const
  60   {
  61     return (xlen == rhs.xlen && flen == rhs.flen
  62             && embedded == rhs.embedded && vlen == rhs.vlen);
  63   }
  64
  65   /* Inequality operator.  */
  66   bool operator!= (const struct riscv_gdbarch_features &rhs) const
  67   {
  68     return !((*this) == rhs);
  69   }
  70
  71   /* Used by std::unordered_map to hash feature sets.  */
  72   std::size_t hash () const noexcept
  73   {
  74     std::size_t val = ((embedded ? 1 : 0) << 10
  75                        | (xlen & 0x1f) << 5
  76                        | (flen & 0x1f) << 0
  77                        | (vlen & 0xfff) << 11);
  78     return val;
  79   }
  80 };
  81
  82 #ifdef GDBSERVER
  83
  84 /* Create and return a target description that is compatible with FEATURES.
  85    This is only used directly from the gdbserver where the created target
  86    description is modified after it is return.  */
  87
  88 target_desc_up riscv_create_target_description
  89         (const struct riscv_gdbarch_features features);
  90
  91 #else
  92
  93 /* Lookup an already existing target description matching FEATURES, or
  94    create a new target description if this is the first time we have seen
  95    FEATURES.  For the same FEATURES the same target_desc is always
  96    returned.  This is important when trying to lookup gdbarch objects as
  97    GDBARCH_LIST_LOOKUP_BY_INFO performs a pointer comparison on target
  98    descriptions to find candidate gdbarch objects.  */
  99
 100 const target_desc *riscv_lookup_target_description
 101         (const struct riscv_gdbarch_features features);
 102
 103 #endif /* GDBSERVER */
 104
 105
 106 #endif /* ARCH_RISCV_H */