drsyms: implement type info for DWARF2

_From [bruen...@google.com](https://code.google.com/u/109494838902877177630/) on August 03, 2012 10:36:55_

issue #605 was only implemented for Windows

for Dr. Memory issue #827 (linux USE_DRSYMS) plus Dr. Memory issue #794 (-replace_malloc) we'll need arg type info (to distinguish placement and nothrow forms of operator new; and as noted in issue #605 , requesting mangled forms may not be a sufficient alternative)

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=860_

Start by reading issue #605 and the existing Windows implementation it describes, then review how drsyms handles DWARF2 on Linux. Done means providing argument type information needed to distinguish placement and nothrow forms of operator new for the Dr. Memory use cases in issues #827 and #794.

Written by the indexing model from the issue text.