/* Interface to C preprocessor macro tables for GDB.
- Copyright (C) 2002, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2007, 2008 Free Software Foundation, Inc.
Contributed by Red Hat, Inc.
This file is part of GDB.
amongst compilation units in an executable file; if BCACHE is zero,
don't cache these things.
- Note that, if either OBSTACK or BCACHE are non-zero, then you
- should only ever add information the macro table --- you should
- never remove things from it. You'll get an error if you try. At
- the moment, since we only provide obstacks and bcaches for macro
- tables for symtabs, this restriction makes a nice sanity check.
- Obstacks and bcaches are pretty much grow-only structures anyway.
- However, if we find that it's occasionally useful to delete things
- even from the symtab's tables, and the storage leak isn't a
- problem, this restriction could be lifted. */
+ Note that, if either OBSTACK or BCACHE are non-zero, then removing
+ information from the table may leak memory. Neither obstacks nor
+ bcaches really allow you to remove information, so although we can
+ update the data structure to record the change, we can't free the
+ old data. At the moment, since we only provide obstacks and
+ bcaches for macro tables for symtabs, this isn't a problem; only
+ odd debugging information makes a definition and then deletes it at
+ the same source location (although 'gcc -DFOO -UFOO -DFOO=2' does
+ do that in GCC 4.1.2.). */
struct macro_table *new_macro_table (struct obstack *obstack,
struct bcache *bcache);