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.

6 files changed, 2437 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 93a2353ba3c..9e4130f15f6 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2002-05-08  Jim Blandy  <jimb@redhat.com>
+
+	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.
+
 2002-05-06  Jim Blandy  <jimb@redhat.com>
 
 	Separate the job of reading the line number info statement program
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index de30f43e792..3cb65a5d03b 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -539,6 +539,7 @@ SFILES = ax-general.c ax-gdb.c bcache.c blockframe.c breakpoint.c \
 	m2-exp.y m2-lang.c m2-typeprint.c m2-valprint.c main.c maint.c \
 	memattr.c mem-break.c minsyms.c mipsread.c nlmread.c objfiles.c \
 	p-exp.y p-lang.c p-typeprint.c p-valprint.c parse.c \
+	macrotab.c macroexp.c \
 	printcmd.c remote.c remote-nrom.c scm-exp.c scm-lang.c \
 	scm-valprint.c source.c stabsread.c stack.c symfile.c \
 	symmisc.c symtab.c linespec.c target.c thread.c top.c tracepoint.c \
@@ -571,6 +572,7 @@ dis_asm_h =	$(INCLUDE_DIR)/dis-asm.h
 remote-sim_h =	$(INCLUDE_DIR)/remote-sim.h
 demangle_h =    $(INCLUDE_DIR)/demangle.h
 obstack_h =     $(INCLUDE_DIR)/obstack.h
+splay_tree_h =  $(INCLUDE_DIR)/splay-tree.h
 
 readline_headers = \
 	$(READLINE_SRC)/chardefs.h \
@@ -631,6 +633,8 @@ inf_loop_h =  	inf-loop.h
 inferior_h =	inferior.h $(breakpoint_h)
 language_h =	language.h
 linespec_h =	linespec.h
+macroexp_h =	macroexp.h
+macrotab_h =    macrotab.h $(obstack_h) $(bcache_h)
 memattr_h =     memattr.h
 monitor_h =	monitor.h
 objfiles_h =	objfiles.h
@@ -669,6 +673,7 @@ HFILES_NO_SRCDIR = bcache.h buildsym.h call-cmds.h coff-solib.h defs.h \
 	gdb-stabs.h $(inferior_h) language.h minimon.h monitor.h \
 	objfiles.h parser-defs.h serial.h solib.h \
 	symfile.h stabsread.h target.h terminal.h typeprint.h xcoffsolib.h \
+	macrotab.h macroexp.h \
 	c-lang.h ch-lang.h f-lang.h \
 	jv-lang.h \
 	m2-lang.h  p-lang.h \
@@ -711,6 +716,7 @@ COMMON_OBS = version.o blockframe.o breakpoint.o findvar.o regcache.o \
 	source.o values.o eval.o valops.o valarith.o valprint.o printcmd.o \
 	symtab.o symfile.o symmisc.o linespec.o infcmd.o infrun.o \
 	expprint.o environ.o stack.o thread.o \
+	macrotab.o macroexp.o \
 	event-loop.o event-top.o inf-loop.o completer.o \
 	gdbarch.o arch-utils.o gdbtypes.o copying.o $(DEPFILES) \
 	memattr.o mem-break.o target.o parse.o language.o $(YYOBJ) buildsym.o \
@@ -2112,6 +2118,11 @@ linespec.o: linespec.c $(linespec_h) $(defs_h) $(frame_h) $(value_h) \
 	$(objfiles_h) $(symfile_h) $(completer_h) $(symtab_h) \
 	$(demangle_h) $(command_h) $(cp_abi_h)
 
+macroexp.o: macroexp.c $(defs_h) $(macrotab_h)
+
+macrotab.o: macrotab.c $(defs_h) $(obstack_h) $(objfiles_h) $(symtab_h) \
+	$(macrotab_h) $(splay_tree_h) gdb_assert.h $(bcache_h)
+
 target.o: target.c $(bfd_h) $(defs_h) $(gdbcmd_h) $(inferior_h) \
 	$(objfiles_h) $(symfile_h) $(target_h) $(gdb_string_h) $(regcache_h)
 
diff --git a/gdb/macroexp.c b/gdb/macroexp.c
new file mode 100644
index 00000000000..cb97f423483
--- /dev/null
+++ b/gdb/macroexp.c
@@ -0,0 +1,1169 @@
+/* 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.  */
+
+#include "defs.h"
+#include "obstack.h"
+#include "bcache.h"
+#include "macrotab.h"
+#include "macroexp.h"
+#include "gdb_assert.h"
+
+
+
+/* A resizeable, substringable string type.  */
+
+
+/* A string type that we can resize, quickly append to, and use to
+   refer to substrings of other strings.  */
+struct macro_buffer
+{
+  /* An array of characters.  The first LEN bytes are the real text,
+     but there are SIZE bytes allocated to the array.  If SIZE is
+     zero, then this doesn't point to a malloc'ed block.  If SHARED is
+     non-zero, then this buffer is actually a pointer into some larger
+     string, and we shouldn't append characters to it, etc.  Because
+     of sharing, we can't assume in general that the text is
+     null-terminated.  */
+  char *text;
+
+  /* The number of characters in the string.  */
+  int len;
+
+  /* The number of characters allocated to the string.  If SHARED is
+     non-zero, this is meaningless; in this case, we set it to zero so
+     that any "do we have room to append something?" tests will fail,
+     so we don't always have to check SHARED before using this field.  */
+  int size;
+
+  /* Zero if TEXT can be safely realloc'ed (i.e., it's its own malloc
+     block).  Non-zero if TEXT is actually pointing into the middle of
+     some other block, and we shouldn't reallocate it.  */
+  int shared;
+
+  /* For detecting token splicing. 
+
+     This is the index in TEXT of the first character of the token
+     that abuts the end of TEXT.  If TEXT contains no tokens, then we
+     set this equal to LEN.  If TEXT ends in whitespace, then there is
+     no token abutting the end of TEXT (it's just whitespace), and
+     again, we set this equal to LEN.  We set this to -1 if we don't
+     know the nature of TEXT.  */
+  int last_token;
+
+  /* If this buffer is holding the result from get_token, then this 
+     is non-zero if it is an identifier token, zero otherwise.  */
+  int is_identifier;
+};
+
+
+/* Set the macro buffer *B to the empty string, guessing that its
+   final contents will fit in N bytes.  (It'll get resized if it
+   doesn't, so the guess doesn't have to be right.)  Allocate the
+   initial storage with xmalloc.  */
+static void
+init_buffer (struct macro_buffer *b, int n)
+{
+  /* Small value for initial testing.  */
+  n = 1;
+
+  b->size = n;
+  if (n > 0)
+    b->text = (char *) xmalloc (n);
+  else
+    b->text = 0;
+  b->len = 0;
+  b->shared = 0;
+  b->last_token = -1;
+}
+
+
+/* Set the macro buffer *BUF to refer to the LEN bytes at ADDR, as a
+   shared substring.  */
+static void
+init_shared_buffer (struct macro_buffer *buf, char *addr, int len)
+{
+  buf->text = addr;
+  buf->len = len;
+  buf->shared = 1;
+  buf->size = 0;
+  buf->last_token = -1;
+}
+
+
+/* Free the text of the buffer B.  Raise an error if B is shared.  */
+static void
+free_buffer (struct macro_buffer *b)
+{
+  gdb_assert (! b->shared);
+  if (b->size)
+    xfree (b->text);
+}
+
+
+/* A cleanup function for macro buffers.  */
+static void
+cleanup_macro_buffer (void *untyped_buf)
+{
+  free_buffer ((struct macro_buffer *) untyped_buf);
+}
+
+
+/* Resize the buffer B to be at least N bytes long.  Raise an error if
+   B shouldn't be resized.  */
+static void
+resize_buffer (struct macro_buffer *b, int n)
+{
+  /* We shouldn't be trying to resize shared strings.  */
+  gdb_assert (! b->shared);
+  
+  if (b->size == 0)
+    b->size = n;
+  else
+    while (b->size <= n)
+      b->size *= 2;
+
+  b->text = xrealloc (b->text, b->size);
+}
+
+
+/* Append the character C to the buffer B.  */
+static inline void
+appendc (struct macro_buffer *b, int c)
+{
+  int new_len = b->len + 1;
+
+  if (new_len > b->size)
+    resize_buffer (b, new_len);
+
+  b->text[b->len] = c;
+  b->len = new_len;
+}
+
+
+/* Append the LEN bytes at ADDR to the buffer B.  */
+static inline void
+appendmem (struct macro_buffer *b, char *addr, int len)
+{
+  int new_len = b->len + len;
+
+  if (new_len > b->size)
+    resize_buffer (b, new_len);
+
+  memcpy (b->text + b->len, addr, len);
+  b->len = new_len;
+}
+
+
+
+/* Recognizing preprocessor tokens.  */
+
+
+static int
+is_whitespace (int c)
+{
+  return (c == ' '
+          || c == '\t'
+          || c == '\n'
+          || c == '\v'
+          || c == '\f');
+}
+
+
+static int
+is_digit (int c)
+{
+  return ('0' <= c && c <= '9');
+}
+
+
+static int
+is_identifier_nondigit (int c)
+{
+  return (c == '_'
+          || ('a' <= c && c <= 'z')
+          || ('A' <= c && c <= 'Z'));
+}
+
+
+static void
+set_token (struct macro_buffer *tok, char *start, char *end)
+{
+  init_shared_buffer (tok, start, end - start);
+  tok->last_token = 0;
+
+  /* Presumed; get_identifier may overwrite this. */
+  tok->is_identifier = 0;
+}
+
+
+static int
+get_comment (struct macro_buffer *tok, char *p, char *end)
+{
+  if (p + 2 > end)
+    return 0;
+  else if (p[0] == '/'
+           && p[1] == '*')
+    {
+      char *tok_start = p;
+
+      p += 2;
+
+      for (; p < end; p++)
+        if (p + 2 <= end
+            && p[0] == '*'
+            && p[1] == '/')
+          {
+            p += 2;
+            set_token (tok, tok_start, p);
+            return 1;
+          }
+
+      error ("Unterminated comment in macro expansion.");
+    }
+  else if (p[0] == '/'
+           && p[1] == '/')
+    {
+      char *tok_start = p;
+
+      p += 2;
+      for (; p < end; p++)
+        if (*p == '\n')
+          break;
+
+      set_token (tok, tok_start, p);
+      return 1;
+    }
+  else
+    return 0;
+}
+
+
+static int
+get_identifier (struct macro_buffer *tok, char *p, char *end)
+{
+  if (p < end
+      && is_identifier_nondigit (*p))
+    {
+      char *tok_start = p;
+
+      while (p < end
+             && (is_identifier_nondigit (*p)
+                 || is_digit (*p)))
+        p++;
+
+      set_token (tok, tok_start, p);
+      tok->is_identifier = 1;
+      return 1;
+    }
+  else
+    return 0;
+}
+
+
+static int
+get_pp_number (struct macro_buffer *tok, char *p, char *end)
+{
+  if (p < end
+      && (is_digit (*p)
+          || *p == '.'))
+    {
+      char *tok_start = p;
+
+      while (p < end)
+        {
+          if (is_digit (*p)
+              || is_identifier_nondigit (*p)
+              || *p == '.')
+            p++;
+          else if (p + 2 <= end
+                   && strchr ("eEpP.", *p)
+                   && (p[1] == '+' || p[1] == '-'))
+            p += 2;
+          else
+            break;
+        }
+
+      set_token (tok, tok_start, p);
+      return 1;
+    }
+  else
+    return 0;
+}
+
+
+
+/* If the text starting at P going up to (but not including) END
+   starts with a character constant, set *TOK to point to that
+   character constant, and return 1.  Otherwise, return zero.
+   Signal an error if it contains a malformed or incomplete character
+   constant.  */
+static int
+get_character_constant (struct macro_buffer *tok, char *p, char *end)
+{
+  /* ISO/IEC 9899:1999 (E)  Section 6.4.4.4  paragraph 1 
+     But of course, what really matters is that we handle it the same
+     way GDB's C/C++ lexer does.  So we call parse_escape in utils.c
+     to handle escape sequences.  */
+  if ((p + 1 <= end && *p == '\'')
+      || (p + 2 <= end && p[0] == 'L' && p[1] == '\''))
+    {
+      char *tok_start = p;
+      char *body_start;
+
+      if (*p == '\'')
+        p++;
+      else if (*p == 'L')
+        p += 2;
+      else
+        gdb_assert (0);
+
+      body_start = p;
+      for (;;)
+        {
+          if (p >= end)
+            error ("Unmatched single quote.");
+          else if (*p == '\'')
+            {
+              if (p == body_start)
+                error ("A character constant must contain at least one "
+                       "character.");
+              p++;
+              break;
+            }
+          else if (*p == '\\')
+            {
+              p++;
+              parse_escape (&p);
+            }
+          else
+            p++;
+        }
+
+      set_token (tok, tok_start, p);
+      return 1;
+    }
+  else
+    return 0;
+}
+
+
+/* If the text starting at P going up to (but not including) END
+   starts with a string literal, set *TOK to point to that string
+   literal, and return 1.  Otherwise, return zero.  Signal an error if
+   it contains a malformed or incomplete string literal.  */
+static int
+get_string_literal (struct macro_buffer *tok, char *p, char *end)
+{
+  if ((p + 1 <= end
+       && *p == '\"')
+      || (p + 2 <= end
+          && p[0] == 'L'
+          && p[1] == '\"'))
+    {
+      char *tok_start = p;
+
+      if (*p == '\"')
+        p++;
+      else if (*p == 'L')
+        p += 2;
+      else
+        gdb_assert (0);
+
+      for (;;)
+        {
+          if (p >= end)
+            error ("Unterminated string in expression.");
+          else if (*p == '\"')
+            {
+              p++;
+              break;
+            }
+          else if (*p == '\n')
+            error ("Newline characters may not appear in string "
+                   "constants.");
+          else if (*p == '\\')
+            {
+              p++;
+              parse_escape (&p);
+            }
+          else
+            p++;
+        }
+
+      set_token (tok, tok_start, p);
+      return 1;
+    }
+  else
+    return 0;
+}
+
+
+static int
+get_punctuator (struct macro_buffer *tok, char *p, char *end)
+{
+  /* Here, speed is much less important than correctness and clarity.  */
+
+  /* ISO/IEC 9899:1999 (E)  Section 6.4.6  Paragraph 1  */
+  static const char * const punctuators[] = {
+    "[", "]", "(", ")", "{", "}", ".", "->", 
+    "++", "--", "&", "*", "+", "-", "~", "!",
+    "/", "%", "<<", ">>", "<", ">", "<=", ">=", "==", "!=", 
+    "^", "|", "&&", "||",
+    "?", ":", ";", "...",
+    "=", "*=", "/=", "%=", "+=", "-=", "<<=", ">>=", "&=", "^=", "|=",
+    ",", "#", "##",
+    "<:", ":>", "<%", "%>", "%:", "%:%:",
+    0
+  };
+
+  int i;
+
+  if (p + 1 <= end)
+    {
+      for (i = 0; punctuators[i]; i++)
+        {
+          const char *punctuator = punctuators[i];
+
+          if (p[0] == punctuator[0])
+            {
+              int len = strlen (punctuator);
+
+              if (p + len <= end
+                  && ! memcmp (p, punctuator, len))
+                {
+                  set_token (tok, p, p + len);
+                  return 1;
+                }
+            }
+        }
+    }
+
+  return 0;
+}
+
+
+/* Peel the next preprocessor token off of SRC, and put it in TOK.
+   Mutate TOK to refer to the first token in SRC, and mutate SRC to
+   refer to the text after that token.  SRC must be a shared buffer;
+   the resulting TOK will be shared, pointing into the same string SRC
+   does.  Initialize TOK's last_token field.  Return non-zero if we
+   succeed, or 0 if we didn't find any more tokens in SRC.  */
+static int
+get_token (struct macro_buffer *tok,
+           struct macro_buffer *src)
+{
+  char *p = src->text;
+  char *end = p + src->len;
+
+  gdb_assert (src->shared);
+
+  /* From the ISO C standard, ISO/IEC 9899:1999 (E), section 6.4:
+
+     preprocessing-token: 
+         header-name
+         identifier
+         pp-number
+         character-constant
+         string-literal
+         punctuator
+         each non-white-space character that cannot be one of the above
+
+     We don't have to deal with header-name tokens, since those can
+     only occur after a #include, which we will never see.  */
+
+  while (p < end)
+    if (is_whitespace (*p))
+      p++;
+    else if (get_comment (tok, p, end))
+      p += tok->len;
+    else if (get_pp_number (tok, p, end)
+             || get_character_constant (tok, p, end)
+             || get_string_literal (tok, p, end)
+             /* Note: the grammar in the standard seems to be
+                ambiguous: L'x' can be either a wide character
+                constant, or an identifier followed by a normal
+                character constant.  By trying `get_identifier' after
+                we try get_character_constant and get_string_literal,
+                we give the wide character syntax precedence.  Now,
+                since GDB doesn't handle wide character constants
+                anyway, is this the right thing to do?  */
+             || get_identifier (tok, p, end)
+             || get_punctuator (tok, p, end))
+      {
+        /* How many characters did we consume, including whitespace?  */
+        int consumed = p - src->text + tok->len;
+        src->text += consumed;
+        src->len -= consumed;
+        return 1;
+      }
+    else 
+      {
+        /* We have found a "non-whitespace character that cannot be
+           one of the above."  Make a token out of it.  */
+        int consumed;
+
+        set_token (tok, p, p + 1);
+        consumed = p - src->text + tok->len;
+        src->text += consumed;
+        src->len -= consumed;
+        return 1;
+      }
+
+  return 0;
+}
+
+
+
+/* Appending token strings, with and without splicing  */
+
+
+/* Append the macro buffer SRC to the end of DEST, and ensure that
+   doing so doesn't splice the token at the end of SRC with the token
+   at the beginning of DEST.  SRC and DEST must have their last_token
+   fields set.  Upon return, DEST's last_token field is set correctly.
+
+   For example:
+
+   If DEST is "(" and SRC is "y", then we can return with
+   DEST set to "(y" --- we've simply appended the two buffers.
+
+   However, if DEST is "x" and SRC is "y", then we must not return
+   with DEST set to "xy" --- that would splice the two tokens "x" and
+   "y" together to make a single token "xy".  However, it would be
+   fine to return with DEST set to "x y".  Similarly, "<" and "<" must
+   yield "< <", not "<<", etc.  */
+static void
+append_tokens_without_splicing (struct macro_buffer *dest,
+                                struct macro_buffer *src)
+{
+  int original_dest_len = dest->len;
+  struct macro_buffer dest_tail, new_token;
+
+  gdb_assert (src->last_token != -1);
+  gdb_assert (dest->last_token != -1);
+  
+  /* First, just try appending the two, and call get_token to see if
+     we got a splice.  */
+  appendmem (dest, src->text, src->len);
+
+  /* If DEST originally had no token abutting its end, then we can't
+     have spliced anything, so we're done.  */
+  if (dest->last_token == original_dest_len)
+    {
+      dest->last_token = original_dest_len + src->last_token;
+      return;
+    }
+
+  /* Set DEST_TAIL to point to the last token in DEST, followed by
+     all the stuff we just appended.  */
+  init_shared_buffer (&dest_tail,
+                      dest->text + dest->last_token,
+                      dest->len - dest->last_token);
+
+  /* Re-parse DEST's last token.  We know that DEST used to contain
+     at least one token, so if it doesn't contain any after the
+     append, then we must have spliced "/" and "*" or "/" and "/" to
+     make a comment start.  (Just for the record, I got this right
+     the first time.  This is not a bug fix.)  */
+  if (get_token (&new_token, &dest_tail)
+      && (new_token.text + new_token.len
+          == dest->text + original_dest_len))
+    {
+      /* No splice, so we're done.  */
+      dest->last_token = original_dest_len + src->last_token;
+      return;
+    }
+
+  /* Okay, a simple append caused a splice.  Let's chop dest back to
+     its original length and try again, but separate the texts with a
+     space.  */
+  dest->len = original_dest_len;
+  appendc (dest, ' ');
+  appendmem (dest, src->text, src->len);
+
+  init_shared_buffer (&dest_tail,
+                      dest->text + dest->last_token,
+                      dest->len - dest->last_token);
+
+  /* Try to re-parse DEST's last token, as above.  */
+  if (get_token (&new_token, &dest_tail)
+      && (new_token.text + new_token.len
+          == dest->text + original_dest_len))
+    {
+      /* No splice, so we're done.  */
+      dest->last_token = original_dest_len + 1 + src->last_token;
+      return;
+    }
+
+  /* As far as I know, there's no case where inserting a space isn't
+     enough to prevent a splice.  */
+  internal_error (__FILE__, __LINE__,
+                  "unable to avoid splicing tokens during macro expansion");
+}
+
+
+
+/* Expanding macros!  */
+
+
+/* A singly-linked list of the names of the macros we are currently 
+   expanding --- for detecting expansion loops.  */
+struct macro_name_list {
+  const char *name;
+  struct macro_name_list *next;
+};
+
+
+/* Return non-zero if we are currently expanding the macro named NAME,
+   according to LIST; otherwise, return zero.
+
+   You know, it would be possible to get rid of all the NO_LOOP
+   arguments to these functions by simply generating a new lookup
+   function and baton which refuses to find the definition for a
+   particular macro, and otherwise delegates the decision to another
+   function/baton pair.  But that makes the linked list of excluded
+   macros chained through untyped baton pointers, which will make it
+   harder to debug.  :( */
+static int
+currently_rescanning (struct macro_name_list *list, const char *name)
+{
+  for (; list; list = list->next)
+    if (! strcmp (name, list->name))
+      return 1;
+
+  return 0;
+}
+
+
+/* Gather the arguments to a macro expansion.
+
+   NAME is the name of the macro being invoked.  (It's only used for
+   printing error messages.)
+
+   Assume that SRC is the text of the macro invocation immediately
+   following the macro name.  For example, if we're processing the
+   text foo(bar, baz), then NAME would be foo and SRC will be (bar,
+   baz).
+
+   If SRC doesn't start with an open paren ( token at all, return
+   zero, leave SRC unchanged, and don't set *ARGC_P to anything.
+
+   If SRC doesn't contain a properly terminated argument list, then
+   raise an error.
+
+   Otherwise, return a pointer to the first element of an array of
+   macro buffers referring to the argument texts, and set *ARGC_P to
+   the number of arguments we found --- the number of elements in the
+   array.  The macro buffers share their text with SRC, and their
+   last_token fields are initialized.  The array is allocated with
+   xmalloc, and the caller is responsible for freeing it.
+
+   NOTE WELL: if SRC starts with a open paren ( token followed
+   immediately by a close paren ) token (e.g., the invocation looks
+   like "foo()"), we treat that as one argument, which happens to be
+   the empty list of tokens.  The caller should keep in mind that such
+   a sequence of tokens is a valid way to invoke one-parameter
+   function-like macros, but also a valid way to invoke zero-parameter
+   function-like macros.  Eeew.
+
+   Consume the tokens from SRC; after this call, SRC contains the text
+   following the invocation.  */
+
+static struct macro_buffer *
+gather_arguments (const char *name, struct macro_buffer *src, int *argc_p)
+{
+  struct macro_buffer tok;
+  int args_len, args_size;
+  struct macro_buffer *args = 0;
+  struct cleanup *back_to = make_cleanup (free_current_contents, &args);
+
+  /* Does SRC start with an opening paren token?  Read from a copy of
+     SRC, so SRC itself is unaffected if we don't find an opening
+     paren.  */
+  {
+    struct macro_buffer temp;
+    init_shared_buffer (&temp, src->text, src->len);
+
+    if (! get_token (&tok, &temp)
+        || tok.len != 1
+        || tok.text[0] != '(')
+      {
+        discard_cleanups (back_to);
+        return 0;
+      }
+  }
+
+  /* Consume SRC's opening paren.  */
+  get_token (&tok, src);
+
+  args_len = 0;
+  args_size = 1;                /* small for initial testing */
+  args = (struct macro_buffer *) xmalloc (sizeof (*args) * args_size);
+
+  for (;;)
+    {
+      struct macro_buffer *arg;
+      int depth;
+
+      /* Make sure we have room for the next argument.  */
+      if (args_len >= args_size)
+        {
+          args_size *= 2;
+          args = xrealloc (args, sizeof (*args) * args_size);
+        }
+
+      /* Initialize the next argument.  */
+      arg = &args[args_len++];
+      set_token (arg, src->text, src->text);
+
+      /* Gather the argument's tokens.  */
+      depth = 0;
+      for (;;)
+        {
+          char *start = src->text;
+
+          if (! get_token (&tok, src))
+            error ("Malformed argument list for macro `%s'.", name);
+      
+          /* Is tok an opening paren?  */
+          if (tok.len == 1 && tok.text[0] == '(')
+            depth++;
+
+          /* Is tok is a closing paren?  */
+          else if (tok.len == 1 && tok.text[0] == ')')
+            {
+              /* If it's a closing paren at the top level, then that's
+                 the end of the argument list.  */
+              if (depth == 0)
+                {
+                  discard_cleanups (back_to);
+                  *argc_p = args_len;
+                  return args;
+                }
+
+              depth--;
+            }
+
+          /* If tok is a comma at top level, then that's the end of
+             the current argument.  */
+          else if (tok.len == 1 && tok.text[0] == ',' && depth == 0)
+            break;
+
+          /* Extend the current argument to enclose this token.  If
+             this is the current argument's first token, leave out any
+             leading whitespace, just for aesthetics.  */
+          if (arg->len == 0)
+            {
+              arg->text = tok.text;
+              arg->len = tok.len;
+              arg->last_token = 0;
+            }
+          else
+            {
+              arg->len = (tok.text + tok.len) - arg->text;
+              arg->last_token = tok.text - arg->text;
+            }
+        }
+    }
+}
+
+
+/* The `expand' and `substitute_args' functions both invoke `scan'
+   recursively, so we need a forward declaration somewhere.  */
+static void scan (struct macro_buffer *dest,
+                  struct macro_buffer *src,
+                  struct macro_name_list *no_loop,
+                  macro_lookup_ftype *lookup_func,
+                  void *lookup_baton);
+
+
+/* Given the macro definition DEF, being invoked with the actual
+   arguments given by ARGC and ARGV, substitute the arguments into the
+   replacement list, and store the result in DEST.
+
+   If it is necessary to expand macro invocations in one of the
+   arguments, use LOOKUP_FUNC and LOOKUP_BATON to find the macro
+   definitions, and don't expand invocations of the macros listed in
+   NO_LOOP.  */
+static void
+substitute_args (struct macro_buffer *dest, 
+                 struct macro_definition *def,
+                 int argc, struct macro_buffer *argv,
+                 struct macro_name_list *no_loop,
+                 macro_lookup_ftype *lookup_func,
+                 void *lookup_baton)
+{
+  /* A macro buffer for the macro's replacement list.  */
+  struct macro_buffer replacement_list;
+
+  init_shared_buffer (&replacement_list, (char *) def->replacement,
+                      strlen (def->replacement));
+
+  gdb_assert (dest->len == 0);
+  dest->last_token = 0;
+
+  for (;;)
+    {
+      struct macro_buffer tok;
+      char *original_rl_start = replacement_list.text;
+      int substituted = 0;
+      
+      /* Find the next token in the replacement list.  */
+      if (! get_token (&tok, &replacement_list))
+        break;
+
+      /* Just for aesthetics.  If we skipped some whitespace, copy
+         that to DEST.  */
+      if (tok.text > original_rl_start)
+        {
+          appendmem (dest, original_rl_start, tok.text - original_rl_start);
+          dest->last_token = dest->len;
+        }
+
+      /* Is this token the stringification operator?  */
+      if (tok.len == 1
+          && tok.text[0] == '#')
+        error ("Stringification is not implemented yet.");
+
+      /* Is this token the splicing operator?  */
+      if (tok.len == 2
+          && tok.text[0] == '#'
+          && tok.text[1] == '#')
+        error ("Token splicing is not implemented yet.");
+
+      /* Is this token an identifier?  */
+      if (tok.is_identifier)
+        {
+          int i;
+
+          /* Is it the magic varargs parameter?  */
+          if (tok.len == 11
+              && ! memcmp (tok.text, "__VA_ARGS__", 11))
+            error ("Variable-arity macros not implemented yet.");
+
+          /* Is it one of the parameters?  */
+          for (i = 0; i < def->argc; i++)
+            if (tok.len == strlen (def->argv[i])
+                && ! memcmp (tok.text, def->argv[i], tok.len))
+              {
+                struct macro_buffer arg_src;
+
+                /* Expand any macro invocations in the argument text,
+                   and append the result to dest.  Remember that scan
+                   mutates its source, so we need to scan a new buffer
+                   referring to the argument's text, not the argument
+                   itself.  */
+                init_shared_buffer (&arg_src, argv[i].text, argv[i].len);
+                scan (dest, &arg_src, no_loop, lookup_func, lookup_baton);
+                substituted = 1;
+                break;
+              }
+        }
+
+      /* If it wasn't a parameter, then just copy it across.  */
+      if (! substituted)
+        append_tokens_without_splicing (dest, &tok);
+    }
+}
+
+
+/* Expand a call to a macro named ID, whose definition is DEF.  Append
+   its expansion to DEST.  SRC is the input text following the ID
+   token.  We are currently rescanning the expansions of the macros
+   named in NO_LOOP; don't re-expand them.  Use LOOKUP_FUNC and
+   LOOKUP_BATON to find definitions for any nested macro references.  
+
+   Return 1 if we decided to expand it, zero otherwise.  (If it's a
+   function-like macro name that isn't followed by an argument list,
+   we don't expand it.)  If we return zero, leave SRC unchanged.  */
+static int
+expand (const char *id,
+        struct macro_definition *def, 
+        struct macro_buffer *dest,
+        struct macro_buffer *src,
+        struct macro_name_list *no_loop,
+        macro_lookup_ftype *lookup_func,
+        void *lookup_baton)
+{
+  struct macro_name_list new_no_loop;
+
+  /* Create a new node to be added to the front of the no-expand list.
+     This list is appropriate for re-scanning replacement lists, but
+     it is *not* appropriate for scanning macro arguments; invocations
+     of the macro whose arguments we are gathering *do* get expanded
+     there.  */
+  new_no_loop.name = id;
+  new_no_loop.next = no_loop;
+
+  /* What kind of macro are we expanding?  */
+  if (def->kind == macro_object_like)
+    {
+      struct macro_buffer replacement_list;
+
+      init_shared_buffer (&replacement_list, (char *) def->replacement,
+                          strlen (def->replacement));
+
+      scan (dest, &replacement_list, &new_no_loop, lookup_func, lookup_baton);
+      return 1;
+    }
+  else if (def->kind == macro_function_like)
+    {
+      struct cleanup *back_to = make_cleanup (null_cleanup, 0);
+      int argc;
+      struct macro_buffer *argv = 0;
+      struct macro_buffer substituted;
+      struct macro_buffer substituted_src;
+
+      if (def->argc >= 1
+          && ! strcmp (def->argv[def->argc - 1], "..."))
+        error ("Varargs macros not implemented yet.");
+
+      make_cleanup (free_current_contents, &argv);
+      argv = gather_arguments (id, src, &argc);
+
+      /* If we couldn't find any argument list, then we don't expand
+         this macro.  */
+      if (! argv)
+        {
+          do_cleanups (back_to);
+          return 0;
+        }
+
+      /* Check that we're passing an acceptable number of arguments for
+         this macro.  */
+      if (argc != def->argc)
+        {
+          /* Remember that a sequence of tokens like "foo()" is a
+             valid invocation of a macro expecting either zero or one
+             arguments.  */
+          if (! (argc == 1
+                 && argv[0].len == 0
+                 && def->argc == 0))
+            error ("Wrong number of arguments to macro `%s' "
+                   "(expected %d, got %d).",
+                   id, def->argc, argc);
+        }
+
+      /* Note that we don't expand macro invocations in the arguments
+         yet --- we let subst_args take care of that.  Parameters that
+         appear as operands of the stringifying operator "#" or the
+         splicing operator "##" don't get macro references expanded,
+         so we can't really tell whether it's appropriate to macro-
+         expand an argument until we see how it's being used.  */
+      init_buffer (&substituted, 0);
+      make_cleanup (cleanup_macro_buffer, &substituted);
+      substitute_args (&substituted, def, argc, argv, no_loop,
+                       lookup_func, lookup_baton);
+
+      /* Now `substituted' is the macro's replacement list, with all
+         argument values substituted into it properly.  Re-scan it for
+         macro references, but don't expand invocations of this macro.
+
+         We create a new buffer, `substituted_src', which points into
+         `substituted', and scan that.  We can't scan `substituted'
+         itself, since the tokenization process moves the buffer's
+         text pointer around, and we still need to be able to find
+         `substituted's original text buffer after scanning it so we
+         can free it.  */
+      init_shared_buffer (&substituted_src, substituted.text, substituted.len);
+      scan (dest, &substituted_src, &new_no_loop, lookup_func, lookup_baton);
+
+      do_cleanups (back_to);
+
+      return 1;
+    }
+  else
+    internal_error (__FILE__, __LINE__, "bad macro definition kind");
+}
+
+
+/* If the single token in SRC_FIRST followed by the tokens in SRC_REST
+   constitute a macro invokation not forbidden in NO_LOOP, append its
+   expansion to DEST and return non-zero.  Otherwise, return zero, and
+   leave DEST unchanged.
+
+   SRC_FIRST and SRC_REST must be shared buffers; DEST must not be one.
+   SRC_FIRST must be a string built by get_token.  */
+static int
+maybe_expand (struct macro_buffer *dest,
+              struct macro_buffer *src_first,
+              struct macro_buffer *src_rest,
+              struct macro_name_list *no_loop,
+              macro_lookup_ftype *lookup_func,
+              void *lookup_baton)
+{
+  gdb_assert (src_first->shared);
+  gdb_assert (src_rest->shared);
+  gdb_assert (! dest->shared);
+
+  /* Is this token an identifier?  */
+  if (src_first->is_identifier)
+    {
+      /* Make a null-terminated copy of it, since that's what our
+         lookup function expects.  */
+      char *id = xmalloc (src_first->len + 1);
+      struct cleanup *back_to = make_cleanup (xfree, id);
+      memcpy (id, src_first->text, src_first->len);
+      id[src_first->len] = 0;
+          
+      /* If we're currently re-scanning the result of expanding
+         this macro, don't expand it again.  */
+      if (! currently_rescanning (no_loop, id))
+        {
+          /* Does this identifier have a macro definition in scope?  */
+          struct macro_definition *def = lookup_func (id, lookup_baton);
+
+          if (def && expand (id, def, dest, src_rest, no_loop,
+                             lookup_func, lookup_baton))
+            {
+              do_cleanups (back_to);
+              return 1;
+            }
+        }
+
+      do_cleanups (back_to);
+    }
+
+  return 0;
+}
+
+
+/* Expand macro references in SRC, appending the results to DEST.
+   Assume we are re-scanning the result of expanding the macros named
+   in NO_LOOP, and don't try to re-expand references to them.
+
+   SRC must be a shared buffer; DEST must not be one.  */
+static void
+scan (struct macro_buffer *dest,
+      struct macro_buffer *src,
+      struct macro_name_list *no_loop,
+      macro_lookup_ftype *lookup_func,
+      void *lookup_baton)
+{
+  gdb_assert (src->shared);
+  gdb_assert (! dest->shared);
+
+  for (;;)
+    {
+      struct macro_buffer tok;
+      char *original_src_start = src->text;
+
+      /* Find the next token in SRC.  */
+      if (! get_token (&tok, src))
+        break;
+
+      /* Just for aesthetics.  If we skipped some whitespace, copy
+         that to DEST.  */
+      if (tok.text > original_src_start)
+        {
+          appendmem (dest, original_src_start, tok.text - original_src_start);
+          dest->last_token = dest->len;
+        }
+
+      if (! maybe_expand (dest, &tok, src, no_loop, lookup_func, lookup_baton))
+        /* We didn't end up expanding tok as a macro reference, so
+           simply append it to dest.  */
+        append_tokens_without_splicing (dest, &tok);
+    }
+
+  /* Just for aesthetics.  If there was any trailing whitespace in
+     src, copy it to dest.  */
+  if (src->len)
+    {
+      appendmem (dest, src->text, src->len);
+      dest->last_token = dest->len;
+    }
+}
+
+
+char *
+macro_expand (const char *source,
+              macro_lookup_ftype *lookup_func,
+              void *lookup_func_baton)
+{
+  struct macro_buffer src, dest;
+  struct cleanup *back_to;
+
+  init_shared_buffer (&src, (char *) source, strlen (source));
+
+  init_buffer (&dest, 0);
+  dest.last_token = 0;
+  back_to = make_cleanup (cleanup_macro_buffer, &dest);
+
+  scan (&dest, &src, 0, lookup_func, lookup_func_baton);
+
+  appendc (&dest, '\0');
+
+  discard_cleanups (back_to);
+  return dest.text;
+}
+
+
+char *
+macro_expand_once (const char *source,
+                   macro_lookup_ftype *lookup_func,
+                   void *lookup_func_baton)
+{
+  error ("Expand-once not implemented yet.");
+}
+
+
+char *
+macro_expand_next (char **lexptr,
+                   macro_lookup_ftype *lookup_func,
+                   void *lookup_baton)
+{
+  struct macro_buffer src, dest, tok;
+  struct cleanup *back_to;
+
+  /* Set up SRC to refer to the input text, pointed to by *lexptr.  */
+  init_shared_buffer (&src, *lexptr, strlen (*lexptr));
+
+  /* Set up DEST to receive the expansion, if there is one.  */
+  init_buffer (&dest, 0);
+  dest.last_token = 0;
+  back_to = make_cleanup (cleanup_macro_buffer, &dest);
+
+  /* Get the text's first preprocessing token.  */
+  if (! get_token (&tok, &src))
+    {
+      do_cleanups (back_to);
+      return 0;
+    }
+
+  /* If it's a macro invocation, expand it.  */
+  if (maybe_expand (&dest, &tok, &src, 0, lookup_func, lookup_baton))
+    {
+      /* It was a macro invocation!  Package up the expansion as a
+         null-terminated string and return it.  Set *lexptr to the
+         start of the next token in the input.  */
+      appendc (&dest, '\0');
+      discard_cleanups (back_to);
+      *lexptr = src.text;
+      return dest.text;
+    }
+  else
+    {
+      /* It wasn't a macro invocation.  */
+      do_cleanups (back_to);
+      return 0;
+    }
+}
diff --git a/gdb/macroexp.h b/gdb/macroexp.h
new file mode 100644
index 00000000000..57269fa22f8
--- /dev/null
+++ b/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 */
diff --git a/gdb/macrotab.c b/gdb/macrotab.c
new file mode 100644
index 00000000000..d73ec9ea489
--- /dev/null
+++ b/gdb/macrotab.c
@@ -0,0 +1,862 @@
+/* C preprocessor macro tables 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.  */
+
+#include "defs.h"
+#include "obstack.h"
+#include "splay-tree.h"
+#include "symtab.h"
+#include "symfile.h"
+#include "objfiles.h"
+#include "macrotab.h"
+#include "gdb_assert.h"
+#include "bcache.h"
+#include "complaints.h"
+
+
+/* The macro table structure.  */
+
+struct macro_table
+{
+  /* The obstack this table's data should be allocated in, or zero if
+     we should use xmalloc.  */
+  struct obstack *obstack;
+
+  /* The bcache we should use to hold macro names, argument names, and
+     definitions, or zero if we should use xmalloc.  */
+  struct bcache *bcache;
+
+  /* The main source file for this compilation unit --- the one whose
+     name was given to the compiler.  This is the root of the
+     #inclusion tree; everything else is #included from here.  */
+  struct macro_source_file *main_source;
+
+  /* The table of macro definitions.  This is a splay tree (an ordered
+     binary tree that stays balanced, effectively), sorted by macro
+     name.  Where a macro gets defined more than once (presumably with
+     an #undefinition in between), we sort the definitions by the
+     order they would appear in the preprocessor's output.  That is,
+     if `a.c' #includes `m.h' and then #includes `n.h', and both
+     header files #define X (with an #undef somewhere in between),
+     then the definition from `m.h' appears in our splay tree before
+     the one from `n.h'.
+
+     The splay tree's keys are `struct macro_key' pointers;
+     the values are `struct macro_definition' pointers.
+
+     The splay tree, its nodes, and the keys and values are allocated
+     in obstack, if it's non-zero, or with xmalloc otherwise.  The
+     macro names, argument names, argument name arrays, and definition
+     strings are all allocated in bcache, if non-zero, or with xmalloc
+     otherwise.  */
+  splay_tree definitions;
+};
+
+
+
+/* Allocation and freeing functions.  */
+
+/* Allocate SIZE bytes of memory appropriately for the macro table T.
+   This just checks whether T has an obstack, or whether its pieces
+   should be allocated with xmalloc.  */
+static void *
+macro_alloc (int size, struct macro_table *t)
+{
+  if (t->obstack)
+    return obstack_alloc (t->obstack, size);
+  else
+    return xmalloc (size);
+}
+
+
+static void
+macro_free (void *object, struct macro_table *t)
+{
+  gdb_assert (! t->obstack);
+  xfree (object);
+}
+
+
+/* If the macro table T has a bcache, then cache the LEN bytes at ADDR
+   there, and return the cached copy.  Otherwise, just xmalloc a copy
+   of the bytes, and return a pointer to that.  */
+static const void *
+macro_bcache (struct macro_table *t, const void *addr, int len)
+{
+  if (t->bcache)
+    return bcache (addr, len, t->bcache);
+  else
+    {
+      void *copy = xmalloc (len);
+      memcpy (copy, addr, len);
+      return copy;
+    }
+}
+
+
+/* If the macro table T has a bcache, cache the null-terminated string
+   S there, and return a pointer to the cached copy.  Otherwise,
+   xmalloc a copy and return that.  */
+static const char *
+macro_bcache_str (struct macro_table *t, const char *s)
+{
+  return (char *) macro_bcache (t, s, strlen (s) + 1);
+}
+
+
+/* Free a possibly bcached object OBJ.  That is, if the macro table T
+   has a bcache, it's an error; otherwise, xfree OBJ.  */
+void
+macro_bcache_free (struct macro_table *t, void *obj)
+{
+  gdb_assert (! t->bcache);
+  xfree (obj);
+}
+
+
+
+/* Macro tree keys, w/their comparison, allocation, and freeing functions.  */
+
+/* A key in the splay tree.  */
+struct macro_key
+{
+  /* The table we're in.  We only need this in order to free it, since
+     the splay tree library's key and value freeing functions require
+     that the key or value contain all the information needed to free
+     themselves.  */
+  struct macro_table *table;
+
+  /* The name of the macro.  This is in the table's bcache, if it has
+     one. */
+  const char *name;
+
+  /* The source file and line number where the definition's scope
+     begins.  This is also the line of the definition itself.  */
+  struct macro_source_file *start_file;
+  int start_line;
+
+  /* The first source file and line after the definition's scope.
+     (That is, the scope does not include this endpoint.)  If end_file
+     is zero, then the definition extends to the end of the
+     compilation unit.  */
+  struct macro_source_file *end_file;
+  int end_line;
+};
+
+
+/* Return the #inclusion depth of the source file FILE.  This is the
+   number of #inclusions it took to reach this file.  For the main
+   source file, the #inclusion depth is zero; for a file it #includes
+   directly, the depth would be one; and so on.  */
+static int
+inclusion_depth (struct macro_source_file *file)
+{
+  int depth;
+
+  for (depth = 0; file->included_by; depth++)
+    file = file->included_by;
+
+  return depth;
+}
+
+
+/* Compare two source locations (from the same compilation unit).
+   This is part of the comparison function for the tree of
+   definitions.
+
+   LINE1 and LINE2 are line numbers in the source files FILE1 and
+   FILE2.  Return a value:
+   - less than zero if {LINE,FILE}1 comes before {LINE,FILE}2,
+   - greater than zero if {LINE,FILE}1 comes after {LINE,FILE}2, or
+   - zero if they are equal.
+
+   When the two locations are in different source files --- perhaps
+   one is in a header, while another is in the main source file --- we
+   order them by where they would appear in the fully pre-processed
+   sources, where all the #included files have been substituted into
+   their places.  */
+static int
+compare_locations (struct macro_source_file *file1, int line1, 
+                   struct macro_source_file *file2, int line2)
+{
+  /* We want to treat positions in an #included file as coming *after*
+     the line containing the #include, but *before* the line after the
+     include.  As we walk up the #inclusion tree toward the main
+     source file, we update fileX and lineX as we go; includedX
+     indicates whether the original position was from the #included
+     file.  */
+  int included1 = 0;
+  int included2 = 0;
+
+  /* If a file is zero, that means "end of compilation unit."  Handle
+     that specially.  */
+  if (! file1)
+    {
+      if (! file2)
+        return 0;
+      else
+        return 1;
+    }
+  else if (! file2)
+    return -1;
+
+  /* If the two files are not the same, find their common ancestor in
+     the #inclusion tree.  */
+  if (file1 != file2)
+    {
+      /* If one file is deeper than the other, walk up the #inclusion
+         chain until the two files are at least at the same *depth*.
+         Then, walk up both files in synchrony until they're the same
+         file.  That file is the common ancestor.  */
+      int depth1 = inclusion_depth (file1);
+      int depth2 = inclusion_depth (file2);
+
+      /* Only one of these while loops will ever execute in any given
+         case.  */
+      while (depth1 > depth2)
+        {
+          line1 = file1->included_at_line;
+          file1 = file1->included_by;
+          included1 = 1;
+          depth1--;
+        }
+      while (depth2 > depth1)
+        {
+          line2 = file2->included_at_line;
+          file2 = file2->included_by;
+          included2 = 1;
+          depth2--;
+        }
+
+      /* Now both file1 and file2 are at the same depth.  Walk toward
+         the root of the tree until we find where the branches meet.  */
+      while (file1 != file2)
+        {
+          line1 = file1->included_at_line;
+          file1 = file1->included_by;
+          /* At this point, we know that the case the includedX flags
+             are trying to deal with won't come up, but we'll just
+             maintain them anyway.  */
+          included1 = 1;
+
+          line2 = file2->included_at_line;
+          file2 = file2->included_by;
+          included2 = 1;
+
+          /* Sanity check.  If file1 and file2 are really from the
+             same compilation unit, then they should both be part of
+             the same tree, and this shouldn't happen.  */
+          gdb_assert (file1 && file2);
+        }
+    }
+
+  /* Now we've got two line numbers in the same file.  */
+  if (line1 == line2)
+    {
+      /* They can't both be from #included files.  Then we shouldn't
+         have walked up this far.  */
+      gdb_assert (! included1 || ! included2);
+
+      /* Any #included position comes after a non-#included position
+         with the same line number in the #including file.  */
+      if (included1)
+        return 1;
+      else if (included2)
+        return -1;
+      else
+        return 0;
+    }
+  else
+    return line1 - line2;
+}
+
+
+/* Compare a macro key KEY against NAME, the source file FILE, and
+   line number LINE.
+
+   Sort definitions by name; for two definitions with the same name,
+   place the one whose definition comes earlier before the one whose
+   definition comes later.
+
+   Return -1, 0, or 1 if key comes before, is identical to, or comes
+   after NAME, FILE, and LINE.  */
+static int
+key_compare (struct macro_key *key,
+             const char *name, struct macro_source_file *file, int line)
+{
+  int names = strcmp (key->name, name);
+  if (names)
+    return names;
+
+  return compare_locations (key->start_file, key->start_line,
+                            file, line);
+}
+
+
+/* The macro tree comparison function, typed for the splay tree
+   library's happiness.  */
+static int
+macro_tree_compare (splay_tree_key untyped_key1,
+                    splay_tree_key untyped_key2)
+{
+  struct macro_key *key1 = (struct macro_key *) untyped_key1;
+  struct macro_key *key2 = (struct macro_key *) untyped_key2;
+
+  return key_compare (key1, key2->name, key2->start_file, key2->start_line);
+}
+
+
+/* Construct a new macro key node for a macro in table T whose name is
+   NAME, and whose scope starts at LINE in FILE; register the name in
+   the bcache.  */
+static struct macro_key *
+new_macro_key (struct macro_table *t,
+               const char *name,
+               struct macro_source_file *file,
+               int line)
+{
+  struct macro_key *k = macro_alloc (sizeof (*k), t);
+
+  memset (k, 0, sizeof (*k));
+  k->table = t;
+  k->name = macro_bcache_str (t, name);
+  k->start_file = file;
+  k->start_line = line;
+  k->end_file = 0;
+
+  return k;
+}
+
+
+static void
+macro_tree_delete_key (void *untyped_key)
+{
+  struct macro_key *key = (struct macro_key *) untyped_key;
+
+  macro_bcache_free (key->table, (char *) key->name);
+  macro_free (key, key->table);
+}
+
+
+
+/* Building and querying the tree of #included files.  */
+
+
+/* Allocate and initialize a new source file structure.  */
+static struct macro_source_file *
+new_source_file (struct macro_table *t,
+                 const char *filename)
+{
+  /* Get space for the source file structure itself.  */
+  struct macro_source_file *f = macro_alloc (sizeof (*f), t);
+
+  memset (f, 0, sizeof (*f));
+  f->table = t;
+  f->filename = macro_bcache_str (t, filename);
+  f->includes = 0;
+
+  return f;
+}
+
+
+/* Free a source file, and all the source files it #included.  */
+static void
+free_macro_source_file (struct macro_source_file *src)
+{
+  struct macro_source_file *child, *next_child;
+
+  /* Free this file's children.  */
+  for (child = src->includes; child; child = next_child)
+    {
+      next_child = child->next_included;
+      free_macro_source_file (child);
+    }
+
+  macro_bcache_free (src->table, (char *) src->filename);
+  macro_free (src, src->table);
+}
+
+
+struct macro_source_file *
+macro_set_main (struct macro_table *t,
+                const char *filename)
+{
+  /* You can't change a table's main source file.  What would that do
+     to the tree?  */
+  gdb_assert (! t->main_source);
+
+  t->main_source = new_source_file (t, filename);
+
+  return t->main_source;
+}
+
+
+struct macro_source_file *
+macro_main (struct macro_table *t)
+{
+  gdb_assert (t->main_source);
+
+  return t->main_source;
+}
+
+
+struct macro_source_file *
+macro_include (struct macro_source_file *source,
+               int line,
+               const char *included)
+{
+  struct macro_source_file *new;
+  struct macro_source_file **link;
+
+  /* Find the right position in SOURCE's `includes' list for the new
+     file.  Scan until we find the first file we shouldn't follow ---
+     which is therefore the file we should directly precede --- or
+     reach the end of the list.  */
+  for (link = &source->includes;
+       *link && line < (*link)->included_at_line;
+       link = &(*link)->next_included)
+    ;
+
+  /* Did we find another file already #included at the same line as
+     the new one?  */
+  if (*link && line == (*link)->included_at_line)
+    {
+      /* This means the compiler is emitting bogus debug info.  (GCC
+         circa March 2002 did this.)  It also means that the splay
+         tree ordering function, macro_tree_compare, will abort,
+         because it can't tell which #inclusion came first.  But GDB
+         should tolerate bad debug info.  So:
+
+         First, squawk.  */
+      static struct complaint bogus_inclusion_line = {
+        "both `%s' and `%s' allegedly #included at %s:%d", 0, 0
+      };
+
+      complain (&bogus_inclusion_line, 
+                included, (*link)->filename, source->filename, line);
+
+      /* Now, choose a new, unoccupied line number for this
+         #inclusion, after the alleged #inclusion line.  */
+      while (*link && line == (*link)->included_at_line)
+        {
+          /* This line number is taken, so try the next line.  */
+          line++;
+          link = &(*link)->next_included;
+        }
+    }
+
+  /* At this point, we know that LINE is an unused line number, and
+     *LINK points to the entry an #inclusion at that line should
+     precede.  */
+  new = new_source_file (source->table, included);
+  new->included_by = source;
+  new->included_at_line = line;
+  new->next_included = *link;
+  *link = new;
+
+  return new;
+}
+
+
+struct macro_source_file *
+macro_lookup_inclusion (struct macro_source_file *source, const char *name)
+{
+  /* Is SOURCE itself named NAME?  */
+  if (! strcmp (name, source->filename))
+    return source;
+
+  /* The filename in the source structure is probably a full path, but
+     NAME could be just the final component of the name.  */
+  {
+    int name_len = strlen (name);
+    int src_name_len = strlen (source->filename);
+
+    /* We do mean < here, and not <=; if the lengths are the same,
+       then the strcmp above should have triggered, and we need to
+       check for a slash here.  */
+    if (name_len < src_name_len
+        && source->filename[src_name_len - name_len - 1] == '/'
+        && ! strcmp (name, source->filename + src_name_len - name_len))
+      return source;
+  }
+
+  /* It's not us.  Try all our children, and return the lowest.  */
+  {
+    struct macro_source_file *child;
+    struct macro_source_file *best = 0;
+    int best_depth;
+
+    for (child = source->includes; child; child = child->next_included)
+      {
+        struct macro_source_file *result
+          = macro_lookup_inclusion (child, name);
+
+        if (result)
+          {
+            int result_depth = inclusion_depth (result);
+
+            if (! best || result_depth < best_depth)
+              {
+                best = result;
+                best_depth = result_depth;
+              }
+          }
+      }
+
+    return best;
+  }
+}
+
+
+
+/* Registering and looking up macro definitions.  */
+
+
+/* Construct a definition for a macro in table T.  Cache all strings,
+   and the macro_definition structure itself, in T's bcache.  */
+static struct macro_definition *
+new_macro_definition (struct macro_table *t,
+                      enum macro_kind kind,
+                      int argc, const char **argv,
+                      const char *replacement)
+{
+  struct macro_definition *d = macro_alloc (sizeof (*d), t);
+
+  memset (d, 0, sizeof (*d));
+  d->table = t;
+  d->kind = kind;
+  d->replacement = macro_bcache_str (t, replacement);
+
+  if (kind == macro_function_like)
+    {
+      int i;
+      const char **cached_argv;
+      int cached_argv_size = argc * sizeof (*cached_argv);
+
+      /* Bcache all the arguments.  */
+      cached_argv = alloca (cached_argv_size);
+      for (i = 0; i < argc; i++)
+        cached_argv[i] = macro_bcache_str (t, argv[i]);
+
+      /* Now bcache the array of argument pointers itself.  */
+      d->argv = macro_bcache (t, cached_argv, cached_argv_size);
+      d->argc = argc;
+    }
+
+  /* We don't bcache the entire definition structure because it's got
+     a pointer to the macro table in it; since each compilation unit
+     has its own macro table, you'd only get bcache hits for identical
+     definitions within a compilation unit, which seems unlikely.
+
+     "So, why do macro definitions have pointers to their macro tables
+     at all?"  Well, when the splay tree library wants to free a
+     node's value, it calls the value freeing function with nothing
+     but the value itself.  It makes the (apparently reasonable)
+     assumption that the value carries enough information to free
+     itself.  But not all macro tables have bcaches, so not all macro
+     definitions would be bcached.  There's no way to tell whether a
+     given definition is bcached without knowing which table the
+     definition belongs to.  ...  blah.  The thing's only sixteen
+     bytes anyway, and we can still bcache the name, args, and
+     definition, so we just don't bother bcaching the definition
+     structure itself.  */
+  return d;
+}
+
+
+/* Free a macro definition.  */
+static void
+macro_tree_delete_value (void *untyped_definition)
+{
+  struct macro_definition *d = (struct macro_definition *) untyped_definition;
+  struct macro_table *t = d->table;
+
+  if (d->kind == macro_function_like)
+    {
+      int i;
+
+      for (i = 0; i < d->argc; i++)
+        macro_bcache_free (t, (char *) d->argv[i]);
+      macro_bcache_free (t, (char **) d->argv);
+    }
+  
+  macro_bcache_free (t, (char *) d->replacement);
+  macro_free (d, t);
+}
+
+
+/* Find the splay tree node for the definition of NAME at LINE in
+   SOURCE, or zero if there is none.  */
+static splay_tree_node
+find_definition (const char *name,
+                 struct macro_source_file *file,
+                 int line)
+{
+  struct macro_table *t = file->table;
+  splay_tree_node n;
+
+  /* Construct a macro_key object, just for the query.  */
+  struct macro_key query;
+
+  query.name = name;
+  query.start_file = file;
+  query.start_line = line;
+  query.end_file = 0;
+
+  n = splay_tree_lookup (t->definitions, (splay_tree_key) &query);
+  if (! n)
+    {
+      /* It's okay for us to do two queries like this: the real work
+         of the searching is done when we splay, and splaying the tree
+         a second time at the same key is a constant time operation.
+         If this still bugs you, you could always just extend the
+         splay tree library with a predecessor-or-equal operation, and
+         use that.  */
+      splay_tree_node pred = splay_tree_predecessor (t->definitions,
+                                                     (splay_tree_key) &query);
+     
+      if (pred)
+        {
+          /* Make sure this predecessor actually has the right name.
+             We just want to search within a given name's definitions.  */
+          struct macro_key *found = (struct macro_key *) pred->key;
+
+          if (! strcmp (found->name, name))
+            n = pred;
+        }
+    }
+
+  if (n)
+    {
+      struct macro_key *found = (struct macro_key *) n->key;
+
+      /* Okay, so this definition has the right name, and its scope
+         begins before the given source location.  But does its scope
+         end after the given source location?  */
+      if (compare_locations (file, line, found->end_file, found->end_line) < 0)
+        return n;
+      else
+        return 0;
+    }
+  else
+    return 0;
+}
+
+
+/* If NAME already has a definition in scope at LINE in FILE, and
+   return the key.  Otherwise, return zero.  */
+static struct macro_key *
+check_for_redefinition (struct macro_source_file *source, int line,
+                        const char *name)
+{
+  splay_tree_node n = find_definition (name, source, line);
+
+  /* This isn't really right.  There's nothing wrong with redefining a
+     macro if the new replacement list is the same as the old one.  */
+  if (n)
+    {
+      struct macro_key *found_key = (struct macro_key *) n->key;
+      static struct complaint macro_redefined = {
+        "macro `%s' redefined at %s:%d;"
+        "original definition at %s:%d", 0, 0
+      };
+      complain (&macro_redefined, name,
+                source->filename, line,
+                found_key->start_file->filename,
+                found_key->start_line);
+      return found_key;
+    }
+  else
+    return 0;
+}
+
+
+void
+macro_define_object (struct macro_source_file *source, int line,
+                     const char *name, const char *replacement)
+{
+  struct macro_table *t = source->table;
+  struct macro_key *k;
+  struct macro_definition *d;
+
+  k = check_for_redefinition (source, line, name);
+
+  /* If we're redefining a symbol, and the existing key would be
+     identical to our new key, then the splay_tree_insert function
+     will try to delete the old definition.  When the definition is
+     living on an obstack, this isn't a happy thing.
+
+     Since this only happens in the presence of questionable debug
+     info, we just ignore all definitions after the first.  The only
+     case I know of where this arises is in GCC's output for
+     predefined macros, and all the definitions are the same in that
+     case.  */
+  if (k && ! key_compare (k, name, source, line))
+    return;
+
+  k = new_macro_key (t, name, source, line);
+  d = new_macro_definition (t, macro_object_like, 0, 0, replacement);
+  splay_tree_insert (t->definitions, (splay_tree_key) k, (splay_tree_value) d);
+}
+
+
+void
+macro_define_function (struct macro_source_file *source, int line,
+                       const char *name, int argc, const char **argv,
+                       const char *replacement)
+{
+  struct macro_table *t = source->table;
+  struct macro_key *k;
+  struct macro_definition *d;
+
+  k = check_for_redefinition (source, line, name);
+
+  /* See comments about duplicate keys in macro_define_object.  */
+  if (k && ! key_compare (k, name, source, line))
+    return;
+
+  /* We should also check here that all the argument names in ARGV are
+     distinct.  */
+
+  k = new_macro_key (t, name, source, line);
+  d = new_macro_definition (t, macro_function_like, argc, argv, replacement);
+  splay_tree_insert (t->definitions, (splay_tree_key) k, (splay_tree_value) d);
+}
+
+
+void
+macro_undef (struct macro_source_file *source, int line,
+             const char *name)
+{
+  splay_tree_node n = find_definition (name, source, line);
+
+  if (n)
+    {
+      /* This function is the only place a macro's end-of-scope
+         location gets set to anything other than "end of the
+         compilation unit" (i.e., end_file is zero).  So if this macro
+         already has its end-of-scope set, then we're probably seeing
+         a second #undefinition for the same #definition.  */
+      struct macro_key *key = (struct macro_key *) n->key;
+
+      if (key->end_file)
+        {
+          static struct complaint double_undef = {
+            "macro '%s' is #undefined twice, at %s:%d and %s:%d",
+            0, 0
+          };
+          complain (&double_undef, name, source->filename, line,
+                    key->end_file->filename, key->end_line);
+        }
+
+      /* Whatever the case, wipe out the old ending point, and 
+         make this the ending point.  */
+      key->end_file = source;
+      key->end_line = line;
+    }
+  else
+    {
+      /* According to the ISO C standard, an #undef for a symbol that
+         has no macro definition in scope is ignored.  So we should
+         ignore it too.  */
+#if 0
+      static struct complaint no_macro_to_undefine = {
+        "no definition for macro `%s' in scope to #undef at %s:%d",
+        0, 0
+      };
+      complain (&no_macro_to_undefine, name, source->filename, line);
+#endif
+    }
+}
+
+
+struct macro_definition *
+macro_lookup_definition (struct macro_source_file *source,
+                         int line, const char *name)
+{
+  splay_tree_node n = find_definition (name, source, line);
+
+  if (n)
+    return (struct macro_definition *) n->value;
+  else
+    return 0;
+}
+
+
+struct macro_source_file *
+macro_definition_location (struct macro_source_file *source,
+                           int line,
+                           const char *name,
+                           int *definition_line)
+{
+  splay_tree_node n = find_definition (name, source, line);
+
+  if (n)
+    {
+      struct macro_key *key = (struct macro_key *) n->key;
+      *definition_line = key->start_line;
+      return key->start_file;
+    }
+  else
+    return 0;
+}
+
+
+
+/* Creating and freeing macro tables.  */
+
+
+struct macro_table *
+new_macro_table (struct obstack *obstack,
+                 struct bcache *b)
+{
+  struct macro_table *t;
+
+  /* First, get storage for the `struct macro_table' itself.  */
+  if (obstack)
+    t = obstack_alloc (obstack, sizeof (*t));
+  else
+    t = xmalloc (sizeof (*t));
+
+  memset (t, 0, sizeof (*t));
+  t->obstack = obstack;
+  t->bcache = b;
+  t->main_source = 0;
+  t->definitions = (splay_tree_new_with_allocator
+                    (macro_tree_compare,
+                     ((splay_tree_delete_key_fn) macro_tree_delete_key),
+                     ((splay_tree_delete_value_fn) macro_tree_delete_value),
+                     ((splay_tree_allocate_fn) macro_alloc),
+                     ((splay_tree_deallocate_fn) macro_free),
+                     t));
+  
+  return t;
+}
+
+
+void
+free_macro_table (struct macro_table *table)
+{
+  /* Free the source file tree.  */
+  free_macro_source_file (table->main_source);
+
+  /* Free the table of macro definitions.  */
+  splay_tree_delete (table->definitions);
+}
diff --git a/gdb/macrotab.h b/gdb/macrotab.h
new file mode 100644
index 00000000000..cbc6d1b53d7
--- /dev/null
+++ b/gdb/macrotab.h
@@ -0,0 +1,295 @@
+/* Interface to C preprocessor macro tables 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 MACROTAB_H
+#define MACROTAB_H
+
+#include "obstack.h"
+#include "bcache.h"
+
+/* How do we represent a source location?  I mean, how should we
+   represent them within GDB; the user wants to use all sorts of
+   ambiguous abbreviations, like "break 32" and "break foo.c:32"
+   ("foo.c" may have been #included into several compilation units),
+   but what do we disambiguate those things to?
+
+   - Answer 1: "Filename and line number."  (Or column number, if
+   you're picky.)  That's not quite good enough.  For example, the
+   same source file can be #included into several different
+   compilation units --- which #inclusion do you mean?
+
+   - Answer 2: "Compilation unit, filename, and line number."  This is
+   a pretty good answer; GDB's `struct symtab_and_line' basically
+   embodies this representation.  But it's still ambiguous; what if a
+   given compilation unit #includes the same file twice --- how can I
+   set a breakpoint on line 12 of the fifth #inclusion of "foo.c"?
+
+   - Answer 3: "Compilation unit, chain of #inclusions, and line
+   number."  This is analogous to the way GCC reports errors in
+   #include files:
+
+        $ gcc -c base.c
+        In file included from header2.h:8,
+                         from header1.h:3,
+                         from base.c:5:
+        header3.h:1: parse error before ')' token
+        $
+
+   GCC tells you exactly what path of #inclusions led you to the
+   problem.  It gives you complete information, in a way that the
+   following would not:
+
+        $ gcc -c base.c
+        header3.h:1: parse error before ')' token
+        $
+
+   Converting all of GDB to use this is a big task, and I'm not really
+   suggesting it should be a priority.  But this module's whole
+   purpose is to maintain structures describing the macro expansion
+   process, so I think it's appropriate for us to take a little care
+   to do that in a complete fashion.
+
+   In this interface, the first line of a file is numbered 1, not 0.
+   This is the same convention the rest of GDB uses.  */
+
+
+/* A table of all the macro definitions for a given compilation unit.  */
+struct macro_table;
+
+
+/* A source file that participated in a compilation unit --- either a
+   main file, or an #included file.  If a file is #included more than
+   once, the presence of the `included_from' and `included_at_line'
+   members means that we need to make one instance of this structure
+   for each #inclusion.  Taken as a group, these structures form a
+   tree mapping the #inclusions that contributed to the compilation
+   unit, with the main source file as its root.
+
+   It's worth noting that libcpp has a simpler way of representing all
+   this, which we should consider switching to.  It might even be
+   suitable for ordinary non-macro line number info.
+
+   Suppose you take your main source file, and after each line
+   containing an #include directive you insert the text of the
+   #included file.  The result is a big file that pretty much
+   corresponds to the full text the compiler's going to see.  There's
+   a one-to-one correspondence between lines in the big file and
+   per-inclusion lines in the source files.  (Obviously, #include
+   directives that are #if'd out don't count.  And you'll need to
+   append a newline to any file that doesn't end in one, to avoid
+   splicing the last #included line with the next line of the
+   #including file.)
+
+   Libcpp calls line numbers in this big imaginary file "logical line
+   numbers", and has a data structure called a "line map" that can map
+   logical line numbers onto actual source filenames and line numbers,
+   and also tell you the chain of #inclusions responsible for any
+   particular logical line number.  Basically, this means you can pass
+   around a single line number and some kind of "compilation unit"
+   object and you get nice, unambiguous source code locations that
+   distinguish between multiple #inclusions of the same file, etc.
+
+   Pretty neat, huh?  */
+
+struct macro_source_file
+{
+
+  /* The macro table for the compilation unit this source location is
+     a part of.  */
+  struct macro_table *table;
+
+  /* A source file --- possibly a header file.  */
+  const char *filename;
+
+  /* The location we were #included from, or zero if we are the
+     compilation unit's main source file.  */
+  struct macro_source_file *included_by;
+
+  /* If `included_from' is non-zero, the line number in that source
+     file at which we were included.  */
+  int included_at_line;
+
+  /* Head of a linked list of the source files #included by this file;
+     our children in the #inclusion tree.  This list is sorted by its
+     elements' `included_at_line' values, which are unique.  (The
+     macro splay tree's ordering function needs this property.)  */
+  struct macro_source_file *includes;
+
+  /* The next file #included by our `included_from' file; our sibling
+     in the #inclusion tree.  */
+  struct macro_source_file *next_included;
+};
+
+
+/* Create a new, empty macro table.  Allocate it in OBSTACK, or use
+   xmalloc if OBSTACK is zero.  Use BCACHE to store all macro names,
+   arguments, definitions, and anything else that might be the same
+   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.  */
+struct macro_table *new_macro_table (struct obstack *obstack,
+                                     struct bcache *bcache);
+
+
+/* Free TABLE, and any macro definitions, source file structures,
+   etc. it owns.  This will raise an internal error if TABLE was
+   allocated on an obstack, or if it uses a bcache.  */
+void free_macro_table (struct macro_table *table);
+
+
+/* Set FILENAME as the main source file of TABLE.  Return a source
+   file structure describing that file; if we record the #definition
+   of macros, or the #inclusion of other files into FILENAME, we'll
+   use that source file structure to indicate the context.
+
+   The "main source file" is the one that was given to the compiler;
+   all other source files that contributed to the compilation unit are
+   #included, directly or indirectly, from this one.
+
+   The macro table makes its own copy of FILENAME; the caller is
+   responsible for freeing FILENAME when it is no longer needed.  */
+struct macro_source_file *macro_set_main (struct macro_table *table,
+                                          const char *filename);
+
+
+/* Return the main source file of the macro table TABLE.  */
+struct macro_source_file *macro_main (struct macro_table *table);
+
+
+/* Record a #inclusion.
+   Record in SOURCE's macro table that, at line number LINE in SOURCE,
+   we #included the file INCLUDED.  Return a source file structure we
+   can use for symbols #defined or files #included into that.  If we've
+   already created a source file structure for this #inclusion, return
+   the same structure we created last time.
+
+   The first line of the source file has a line number of 1, not 0.
+
+   The macro table makes its own copy of INCLUDED; the caller is
+   responsible for freeing INCLUDED when it is no longer needed.  */
+struct macro_source_file *macro_include (struct macro_source_file *source,
+                                         int line,
+                                         const char *included);
+
+
+/* Find any source file structure for a file named NAME, either
+   included into SOURCE, or SOURCE itself.  Return zero if we have
+   none.  NAME is only the final portion of the filename, not the full
+   path.  e.g., `stdio.h', not `/usr/include/stdio.h'.  If NAME
+   appears more than once in the inclusion tree, return the
+   least-nested inclusion --- the one closest to the main source file.  */
+struct macro_source_file *(macro_lookup_inclusion
+                           (struct macro_source_file *source,
+                            const char *name));
+
+
+/* Record an object-like #definition (i.e., one with no parameter list).
+   Record in SOURCE's macro table that, at line number LINE in SOURCE,
+   we #defined a preprocessor symbol named NAME, whose replacement
+   string is REPLACEMENT.  This function makes copies of NAME and
+   REPLACEMENT; the caller is responsible for freeing them.  */
+void macro_define_object (struct macro_source_file *source, int line,
+                          const char *name, const char *replacement);
+
+
+/* Record an function-like #definition (i.e., one with a parameter list).
+
+   Record in SOURCE's macro table that, at line number LINE in SOURCE,
+   we #defined a preprocessor symbol named NAME, with ARGC arguments
+   whose names are given in ARGV, whose replacement string is REPLACEMENT.  If
+   the macro takes a variable number of arguments, then ARGC should be
+   one greater than the number of named arguments, and ARGV[ARGC-1]
+   should be the string "...".  This function makes its own copies of
+   NAME, ARGV, and REPLACEMENT; the caller is responsible for freeing
+   them.  */
+void macro_define_function (struct macro_source_file *source, int line,
+                            const char *name, int argc, const char **argv,
+                            const char *replacement);
+
+
+/* Record an #undefinition.
+   Record in SOURCE's macro table that, at line number LINE in SOURCE,
+   we removed the definition for the preprocessor symbol named NAME.  */
+void macro_undef (struct macro_source_file *source, int line,
+                  const char *name);
+
+
+/* Different kinds of macro definitions.  */
+enum macro_kind
+{
+  macro_object_like,
+  macro_function_like
+};
+
+
+/* A preprocessor symbol definition.  */
+struct macro_definition
+{
+  /* The table this definition lives in.  */
+  struct macro_table *table;
+
+  /* What kind of macro it is.  */
+  enum macro_kind kind;
+
+  /* If `kind' is `macro_function_like', the number of arguments it
+     takes, and their names.  The names, and the array of pointers to
+     them, are in the table's bcache, if it has one.  */
+  int argc;
+  const char * const *argv;
+
+  /* The replacement string (body) of the macro.  This is in the
+     table's bcache, if it has one.  */
+  const char *replacement;
+};
+
+
+/* Return a pointer to the macro definition for NAME in scope at line
+   number LINE of SOURCE.  If LINE is -1, return the definition in
+   effect at the end of the file.  The macro table owns the structure;
+   the caller need not free it.  Return zero if NAME is not #defined
+   at that point.  */
+struct macro_definition *(macro_lookup_definition
+                          (struct macro_source_file *source,
+                           int line, const char *name));
+
+
+/* Return the source location of the definition for NAME in scope at
+   line number LINE of SOURCE.  Set *DEFINITION_LINE to the line
+   number of the definition, and return a source file structure for
+   the file.  Return zero if NAME has no definition in scope at that
+   point, and leave *DEFINITION_LINE unchanged.  */
+struct macro_source_file *(macro_definition_location
+                           (struct macro_source_file *source,
+                            int line,
+                            const char *name,
+                            int *definition_line));
+
+
+#endif /* MACROTAB_H */