gdb/x86-tdep.c

   1 /* Target-dependent code for X86-based targets.
   2
   3    Copyright (C) 2018-2024 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 "x86-tdep.h"
  21 #include "symtab.h"
  22
  23
  24 /* Check whether NAME is included in NAMES[LO] (inclusive) to NAMES[HI]
  25    (exclusive).  */
  26
  27 static bool
  28 x86_is_thunk_register_name (const char *name, const char * const *names,
  29                             int lo, int hi)
  30 {
  31   int reg;
  32   for (reg = lo; reg < hi; ++reg)
  33     if (strcmp (name, names[reg]) == 0)
  34       return true;
  35
  36   return false;
  37 }
  38
  39 /* See x86-tdep.h.  */
  40
  41 bool
  42 x86_in_indirect_branch_thunk (CORE_ADDR pc, const char * const *register_names,
  43                               int lo, int hi)
  44 {
  45   struct bound_minimal_symbol bmfun = lookup_minimal_symbol_by_pc (pc);
  46   if (bmfun.minsym == nullptr)
  47     return false;
  48
  49   const char *name = bmfun.minsym->linkage_name ();
  50   if (name == nullptr)
  51     return false;
  52
  53   /* Check the indirect return thunk first.  */
  54   if (strcmp (name, "__x86_return_thunk") == 0)
  55     return true;
  56
  57   /* Then check a family of indirect call/jump thunks.  */
  58   static const char thunk[] = "__x86_indirect_thunk";
  59   static const size_t length = sizeof (thunk) - 1;
  60   if (strncmp (name, thunk, length) != 0)
  61     return false;
  62
  63   /* If that's the complete name, we're in the memory thunk.  */
  64   name += length;
  65   if (*name == '\0')
  66     return true;
  67
  68   /* Check for suffixes.  */
  69   if (*name++ != '_')
  70     return false;
  71
  72   if (x86_is_thunk_register_name (name, register_names, lo, hi))
  73     return true;
  74
  75   return false;
  76 }