Add first preprocessor macro-expansion files.

* macroexp.c, macroexp.h, macrotab.c, macrotab.h: New files.
* Makefile.in (SFILES): Add macrotab.c, macroexp.c.
(splay_tree_h, macroexp_h, macrotab_h): New variable.
(HFILES_NO_SRCDIR): Add macrotab.h, macroexp.h.
(COMMON_OBS): Add macrotab.o, macroexp.o.
(macroexp.o, macrotab.o): New rules.

gdb/macroexp.h

@@ -0,0 +1,90 @@
+/* Interface to C preprocessor macro expansion for GDB.
+   Copyright 2002 Free Software Foundation, Inc.
+   Contributed by Red Hat, Inc.
+
+   This file is part of GDB.
+
+   This program 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; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+
+#ifndef MACROEXP_H
+#define MACROEXP_H
+
+/* A function for looking up preprocessor macro definitions.  Return
+   the preprocessor definition of NAME in scope according to BATON, or
+   zero if NAME is not defined as a preprocessor macro.
+
+   The caller must not free or modify the definition returned.  It is
+   probably unwise for the caller to hold pointers to it for very
+   long; it probably lives in some objfile's obstacks.  */
+typedef struct macro_definition *(macro_lookup_ftype) (const char *name,
+                                                       void *baton);
+
+
+/* Expand any preprocessor macros in SOURCE, and return the expanded
+   text.  Use LOOKUP_FUNC and LOOKUP_FUNC_BATON to find identifiers'
+   preprocessor definitions.  SOURCE is a null-terminated string.  The
+   result is a null-terminated string, allocated using xmalloc; it is
+   the caller's responsibility to free it.  */
+char *macro_expand (const char *source,
+                    macro_lookup_ftype *lookup_func,
+                    void *lookup_func_baton);
+
+
+/* Expand all preprocessor macro references that appear explicitly in
+   SOURCE, but do not expand any new macro references introduced by
+   that first level of expansion.  Use LOOKUP_FUNC and
+   LOOKUP_FUNC_BATON to find identifiers' preprocessor definitions.
+   SOURCE is a null-terminated string.  The result is a
+   null-terminated string, allocated using xmalloc; it is the caller's
+   responsibility to free it.  */
+char *macro_expand_once (const char *source,
+                         macro_lookup_ftype *lookup_func,
+                         void *lookup_func_baton);
+
+
+/* If the null-terminated string pointed to by *LEXPTR begins with a
+   macro invocation, return the result of expanding that invocation as
+   a null-terminated string, and set *LEXPTR to the next character
+   after the invocation.  The result is completely expanded; it
+   contains no further macro invocations.
+
+   Otherwise, if *LEXPTR does not start with a macro invocation,
+   return zero, and leave *LEXPTR unchanged.
+
+   Use LOOKUP_FUNC and LOOKUP_BATON to find macro definitions.
+
+   If this function returns a string, the caller is responsible for
+   freeing it, using xfree.
+
+   We need this expand-one-token-at-a-time interface in order to
+   accomodate GDB's C expression parser, which may not consume the
+   entire string.  When the user enters a command like
+
+      (gdb) break *func+20 if x == 5
+
+   the parser is expected to consume `func+20', and then stop when it
+   sees the "if".  But of course, "if" appearing in a character string
+   or as part of a larger identifier doesn't count.  So you pretty
+   much have to do tokenization to find the end of the string that
+   needs to be macro-expanded.  Our C/C++ tokenizer isn't really
+   designed to be called by anything but the yacc parser engine.  */
+char *macro_expand_next (char **lexptr,
+                         macro_lookup_ftype *lookup_func,
+                         void *lookup_baton);
+
+
+#endif /* MACROEXP_H */