gdb/x86-tdep.c

   1 /* Target-dependent code for X86-based targets.
   2
   3    Copyright (C) 2018-2022 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 #include "defs.h"
  21 #include "x86-tdep.h"
  22 #include "symtab.h"
  23
  24
  25 /* Check whether NAME is included in NAMES[LO] (inclusive) to NAMES[HI]
  26    (exclusive).  */
  27
  28 static bool
  29 x86_is_thunk_register_name (const char *name, const char * const *names,
  30                             int lo, int hi)
  31 {
  32   int reg;
  33   for (reg = lo; reg < hi; ++reg)
  34     if (strcmp (name, names[reg]) == 0)
  35       return true;
  36
  37   return false;
  38 }
  39
  40 /* See x86-tdep.h.  */
  41
  42 bool
  43 x86_in_indirect_branch_thunk (CORE_ADDR pc, const char * const *register_names,
  44                               int lo, int hi)
  45 {
  46   struct bound_minimal_symbol bmfun = lookup_minimal_symbol_by_pc (pc);
  47   if (bmfun.minsym == nullptr)
  48     return false;
  49
  50   const char *name = bmfun.minsym->linkage_name ();
  51   if (name == nullptr)
  52     return false;
  53
  54   /* Check the indirect return thunk first.  */
  55   if (strcmp (name, "__x86_return_thunk") == 0)
  56     return true;
  57
  58   /* Then check a family of indirect call/jump thunks.  */
  59   static const char thunk[] = "__x86_indirect_thunk";
  60   static const size_t length = sizeof (thunk) - 1;
  61   if (strncmp (name, thunk, length) != 0)
  62     return false;
  63
  64   /* If that's the complete name, we're in the memory thunk.  */
  65   name += length;
  66   if (*name == '\0')
  67     return true;
  68
  69   /* Check for suffixes.  */
  70   if (*name++ != '_')
  71     return false;
  72
  73   if (x86_is_thunk_register_name (name, register_names, lo, hi))
  74     return true;
  75
  76   return false;
  77 }