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      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 }
     77