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   /* When true this target is RV32E.  */
  50   bool embedded = false;
  51
  52   /* Equality operator.  */
  53   bool operator== (const struct riscv_gdbarch_features &rhs) const
  54   {
  55     return (xlen == rhs.xlen && flen == rhs.flen && embedded == rhs.embedded);
  56   }
  57
  58   /* Inequality operator.  */
  59   bool operator!= (const struct riscv_gdbarch_features &rhs) const
  60   {
  61     return !((*this) == rhs);
  62   }
  63
  64   /* Used by std::unordered_map to hash feature sets.  */
  65   std::size_t hash () const noexcept
  66   {
  67     std::size_t val = ((embedded ? 1 : 0) << 10
  68                        | (xlen & 0x1f) << 5
  69                        | (flen & 0x1f) << 0);
  70     return val;
  71   }
  72 };
  73
  74 #ifdef GDBSERVER
  75
  76 /* Create and return a target description that is compatible with FEATURES.
  77    This is only used directly from the gdbserver where the created target
  78    description is modified after it is return.  */
  79
  80 target_desc_up riscv_create_target_description
  81         (const struct riscv_gdbarch_features features);
  82
  83 #else
  84
  85 /* Lookup an already existing target description matching FEATURES, or
  86    create a new target description if this is the first time we have seen
  87    FEATURES.  For the same FEATURES the same target_desc is always
  88    returned.  This is important when trying to lookup gdbarch objects as
  89    GDBARCH_LIST_LOOKUP_BY_INFO performs a pointer comparison on target
  90    descriptions to find candidate gdbarch objects.  */
  91
  92 const target_desc *riscv_lookup_target_description
  93         (const struct riscv_gdbarch_features features);
  94
  95 #endif /* GDBSERVER */
  96
  97
  98 #endif /* ARCH_RISCV_H */