libdwfl/dwfl_module_getsrc_file.c

/* Find matching source locations in a module.
   Copyright (C) 2005 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
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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"

int
dwfl_module_getsrc_file (Dwfl_Module *mod,
			 const char *fname, int lineno, int column,
			 Dwfl_Line ***srcsp, size_t *nsrcs)
{
  if (mod == NULL)
    return -1;

  if (mod->dw == NULL)
    {
      Dwarf_Addr bias;
      if (INTUSE(dwfl_module_getdwarf) (mod, &bias) == NULL)
	return -1;
    }

  bool is_basename = strchr (fname, '/') == NULL;

  size_t max_match = *nsrcs ?: ~0u;
  size_t act_match = *nsrcs;
  size_t cur_match = 0;
  Dwfl_Line **match = *nsrcs == 0 ? NULL : *srcsp;

  struct dwfl_cu *cu = NULL;
  Dwfl_Error error;
  while ((error = __libdwfl_nextcu (mod, cu, &cu)) == DWFL_E_NOERROR
	 && cu != NULL
	 && (error = __libdwfl_cu_getsrclines (cu)) == DWFL_E_NOERROR)
    {
      inline const char *INTUSE(dwarf_line_file) (const Dwarf_Line *line)
	{
	  return line->files->info[line->file].name;
	}
      inline Dwarf_Line *dwfl_line (const Dwfl_Line *line)
	{
	  return &dwfl_linecu (line)->die.cu->lines->info[line->idx];
	}
      inline const char *dwfl_line_file (const Dwfl_Line *line)
	{
	  return INTUSE(dwarf_line_file) (dwfl_line (line));
	}

      /* Search through all the line number records for a matching
	 file and line/column number.  If any of the numbers is zero,
	 no match is performed.  */
      const char *lastfile = NULL;
      bool lastmatch = false;
      for (size_t cnt = 0; cnt < cu->die.cu->lines->nlines; ++cnt)
	{
	  Dwarf_Line *line = &cu->die.cu->lines->info[cnt];

	  if (unlikely (line->file >= line->files->nfiles))
	    {
	      __libdwfl_seterrno (DWFL_E (LIBDW, DWARF_E_INVALID_DWARF));
	      return -1;
	    }
	  else
	    {
	      const char *file = INTUSE(dwarf_line_file) (line);
	      if (file != lastfile)
		{
		  /* Match the name with the name the user provided.  */
		  lastfile = file;
		  lastmatch = !strcmp (is_basename ? basename (file) : file,
				       fname);
		}
	    }
	  if (!lastmatch)
	    continue;

	  /* See whether line and possibly column match.  */
	  if (lineno != 0
	      && (lineno > line->line
		  || (column != 0 && column > line->column)))
	    /* Cannot match.  */
	    continue;

	  /* Determine whether this is the best match so far.  */
	  size_t inner;
	  for (inner = 0; inner < cur_match; ++inner)
	    if (dwfl_line_file (match[inner])
		== INTUSE(dwarf_line_file) (line))
	      break;
	  if (inner < cur_match
	      && (dwfl_line (match[inner])->line != line->line
		  || dwfl_line (match[inner])->line != lineno
		  || (column != 0
		      && (dwfl_line (match[inner])->column != line->column
			  || dwfl_line (match[inner])->column != column))))
	    {
	      /* We know about this file already.  If this is a better
		 match for the line number, use it.  */
	      if (dwfl_line (match[inner])->line >= line->line
		  && (dwfl_line (match[inner])->line != line->line
		      || dwfl_line (match[inner])->column >= line->column))
		/* Use the new line.  Otherwise the old one.  */
		match[inner] = &cu->lines->idx[cnt];
	      continue;
	    }

	  if (cur_match < max_match)
	    {
	      if (cur_match == act_match)
		{
		  /* Enlarge the array for the results.  */
		  act_match += 10;
		  Dwfl_Line **newp = realloc (match,
					      act_match
					      * sizeof (Dwfl_Line *));
		  if (newp == NULL)
		    {
		      free (match);
		      __libdwfl_seterrno (DWFL_E_NOMEM);
		      return -1;
		    }
		  match = newp;
		}

	      match[cur_match++] = &cu->lines->idx[cnt];
	    }
	}
    }

  if (cur_match > 0)
    {
      assert (*nsrcs == 0 || *srcsp == match);

      *nsrcs = cur_match;
      *srcsp = match;

      return 0;
    }

  __libdwfl_seterrno (DWFL_E_NO_MATCH);
  return -1;
}