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      1 /* Find source location for PC address in module.
      2    Copyright (C) 2005, 2008, 2014 Red Hat, Inc.
      3    This file is part of elfutils.
      4 
      5    This file is free software; you can redistribute it and/or modify
      6    it under the terms of either
      7 
      8      * the GNU Lesser General Public License as published by the Free
      9        Software Foundation; either version 3 of the License, or (at
     10        your option) any later version
     11 
     12    or
     13 
     14      * the GNU General Public License as published by the Free
     15        Software Foundation; either version 2 of the License, or (at
     16        your option) any later version
     17 
     18    or both in parallel, as here.
     19 
     20    elfutils is distributed in the hope that it will be useful, but
     21    WITHOUT ANY WARRANTY; without even the implied warranty of
     22    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     23    General Public License for more details.
     24 
     25    You should have received copies of the GNU General Public License and
     26    the GNU Lesser General Public License along with this program.  If
     27    not, see <http://www.gnu.org/licenses/>.  */
     28 
     29 #include "libdwflP.h"
     30 #include "../libdw/libdwP.h"
     31 
     32 Dwfl_Line *
     33 dwfl_module_getsrc (Dwfl_Module *mod, Dwarf_Addr addr)
     34 {
     35   Dwarf_Addr bias;
     36   if (INTUSE(dwfl_module_getdwarf) (mod, &bias) == NULL)
     37     return NULL;
     38 
     39   struct dwfl_cu *cu;
     40   Dwfl_Error error = __libdwfl_addrcu (mod, addr, &cu);
     41   if (likely (error == DWFL_E_NOERROR))
     42     error = __libdwfl_cu_getsrclines (cu);
     43   if (likely (error == DWFL_E_NOERROR))
     44     {
     45       Dwarf_Lines *lines = cu->die.cu->lines;
     46       size_t nlines = lines->nlines;
     47       if (nlines > 0)
     48 	{
     49 	  /* This is guaranteed for us by libdw read_srclines.  */
     50 	  assert(lines->info[nlines - 1].end_sequence);
     51 
     52 	  /* Now we look at the module-relative address.  */
     53 	  addr -= bias;
     54 
     55 	  /* The lines are sorted by address, so we can use binary search.  */
     56 	  size_t l = 0, u = nlines - 1;
     57 	  while (l < u)
     58 	    {
     59 	      size_t idx = u - (u - l) / 2;
     60 	      Dwarf_Line *line = &lines->info[idx];
     61 	      if (addr < line->addr)
     62 		u = idx - 1;
     63 	      else
     64 		l = idx;
     65 	    }
     66 
     67 	  /* The last line which is less than or equal to addr is what we want,
     68 	     except with an end_sequence which can only be strictly equal.  */
     69 	  Dwarf_Line *line = &lines->info[l];
     70 	  if (line->addr == addr
     71 	      || (! line->end_sequence && line->addr < addr))
     72 	    return &cu->lines->idx[l];
     73 	}
     74 
     75       error = DWFL_E_ADDR_OUTOFRANGE;
     76     }
     77 
     78   __libdwfl_seterrno (error);
     79   return NULL;
     80 }
     81 INTDEF (dwfl_module_getsrc)
     82