Support .debug_macro

- This code is based on the following proposal:
    http://www.dwarfstd.org/ShowIssue.php?issue=110722.1

- dwarf_getmacros serves either of .debug_macinfo or .debug_macro
  transparently, but if the latter uses opcode 0xff, it bails out with
  an error.  The reason is that in .debug_macro, 0xff is a custom code
  that can mean anything, while in .debug_macinfo there's fixed
  semantics associated with 0xff.

- dwarf_getmacros_off is a new interface used for requesting iteration
  through transparently included units.

- dwarf_macro_getparamcnt and dwarf_macro_param are new interfaces
  used for requesting number of parameters of an opcode and individual
  parameters.  dwarf_macro_getsrcfiles is a new interface used for
  requesting a file part of .debug_line unit associated with macro
  unit that the opcode comes from.

- The existing interfaces dwarf_macro_opcode, dwarf_macro_param1 and
  dwarf_macro_param2 remain operational for old- as well as new-style
  Dwarf macro sections, if applicable.

- dwarf_getsrclines was made into a light wrapper around a worker
  function that loads line unit given its offset.  The worker also
  caches loaded units in an offset-keyed search tree, so that we don't
  end up re-reading units even though they were read in a different
  domain (e.g. a macro unit request can prime cache for later CU
  lookup).  dwarf_macro_getsrcfiles calls the worker function under
  covers.

Signed-off-by: Petr Machata <pmachata@redhat.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/libdw/dwarf_macro_param.c b/libdw/dwarf_macro_param.c
new file mode 100644
index 00000000..bd846a7f
--- /dev/null
+++ b/libdw/dwarf_macro_param.c
@@ -0,0 +1,46 @@
+/* Return a given parameter of a macro.
+   Copyright (C) 2014 Red Hat, Inc.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils is distributed in the hope that it will be useful, but
+   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.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libdwP.h"
+
+int
+dwarf_macro_param (Dwarf_Macro *macro, size_t idx, Dwarf_Attribute *ret)
+{
+  if (macro == NULL)
+    return -1;
+
+  if (idx >= libdw_macro_nforms (macro))
+    return -1;
+
+  *ret = macro->attributes[idx];
+  return 0;
+}