xref: /external/elfutils/libdwfl/dwfl_module_getsrc.c

/* Find source location for PC address in module.
   Copyright (C) 2005, 2008 Red Hat, Inc.
   This file is part of Red Hat elfutils.

   Red Hat elfutils is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by the
   Free Software Foundation; version 2 of the License.

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   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

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   with Red Hat elfutils; if not, write to the Free Software Foundation,
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   additional right to link the code of Red Hat elfutils with code licensed
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   this file solely under the GPL without exception.

   Red Hat elfutils is an included package of the Open Invention Network.
   An included package of the Open Invention Network is a package for which
   Open Invention Network licensees cross-license their patents.  No patent
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#include "libdwflP.h"
#include "../libdw/libdwP.h"

Dwfl_Line *
dwfl_module_getsrc (Dwfl_Module *mod, Dwarf_Addr addr)
{
  Dwarf_Addr bias;
  if (INTUSE(dwfl_module_getdwarf) (mod, &bias) == NULL)
    return NULL;

  struct dwfl_cu *cu;
  Dwfl_Error error = __libdwfl_addrcu (mod, addr, &cu);
  if (likely (error == DWFL_E_NOERROR))
    error = __libdwfl_cu_getsrclines (cu);
  if (likely (error == DWFL_E_NOERROR))
    {
      /* Now we look at the module-relative address.  */
      addr -= bias;

      /* The lines are sorted by address, so we can use binary search.  */
      size_t l = 0, u = cu->die.cu->lines->nlines;
      while (l < u)
	{
	  size_t idx = (l + u) / 2;
	  if (addr < cu->die.cu->lines->info[idx].addr)
	    u = idx;
	  else if (addr > cu->die.cu->lines->info[idx].addr)
	    l = idx + 1;
	  else
	    return &cu->lines->idx[idx];
	}

      if (cu->die.cu->lines->nlines > 0)
	assert (cu->die.cu->lines->info
		[cu->die.cu->lines->nlines - 1].end_sequence);

      /* If none were equal, the closest one below is what we want.
	 We never want the last one, because it's the end-sequence
	 marker with an address at the high bound of the CU's code.  */
      if (u > 0 && u < cu->die.cu->lines->nlines
	  && addr > cu->die.cu->lines->info[u - 1].addr)
	return &cu->lines->idx[u - 1];

      error = DWFL_E_ADDR_OUTOFRANGE;
    }

  __libdwfl_seterrno (error);
  return NULL;
}
INTDEF (dwfl_module_getsrc)