This is a major update, which switches virtually every allocated-but-not-freed

string into the strcache.  As a side-effect, many more structure members and
function arguments can/should be declared const.

As mentioned in the changelog, unfortunately measurement shows that this
change does not yet reduce memory.  The problem is with secondary expansion:
because of this we store all the prerequisites in the string cache twice.
First we store the prerequisite string after initial expansion but before
secondary expansion, then we store each individual file after secondary
expansion and expand_deps().  I plan to change expand_deps() to be callable
in either context (eval or snap_deps) then have non-second-expansion
targets call expand_deps() during eval, so that we only need to store that
dependency list once.

1 files changed, 254 insertions, 203 deletions

diff --git a/read.c b/read.c
index 6b0c0aa..e50a76c 100644
--- a/read.c
+++ b/read.c
@@ -88,14 +88,12 @@ static struct conditionals *conditionals = &toplevel_conditionals;
 
 /* Default directories to search for include files in  */
 
-static char *default_include_directories[] =
+static const char *default_include_directories[] =
   {
 #if defined(WINDOWS32) && !defined(INCLUDEDIR)
-/*
- * This completely up to the user when they install MSVC or other packages.
- * This is defined as a placeholder.
- */
-#define INCLUDEDIR "."
+/* This completely up to the user when they install MSVC or other packages.
+   This is defined as a placeholder.  */
+# define INCLUDEDIR "."
 #endif
     INCLUDEDIR,
 #ifndef _AMIGA
@@ -108,7 +106,7 @@ static char *default_include_directories[] =
 
 /* List of directories to search for include files in  */
 
-static char **include_directories;
+static const char **include_directories;
 
 /* Maximum length of an element of the above.  */
 
@@ -123,15 +121,15 @@ const struct floc *reading_file = 0;
 
 static struct dep *read_makefiles = 0;
 
-static int eval_makefile (char *filename, int flags);
+static int eval_makefile (const char *filename, int flags);
 static int eval (struct ebuffer *buffer, int flags);
 
 static long readline (struct ebuffer *ebuf);
 static void do_define (char *name, unsigned int namelen,
                        enum variable_origin origin, struct ebuffer *ebuf);
 static int conditional_line (char *line, int len, const struct floc *flocp);
-static void record_files (struct nameseq *filenames, char *pattern,
-                          char *pattern_percent, struct dep *deps,
+static void record_files (struct nameseq *filenames, const char *pattern,
+                          const char *pattern_percent, struct dep *deps,
                           unsigned int cmds_started, char *commands,
                           unsigned int commands_idx, int two_colon,
                           const struct floc *flocp);
@@ -147,7 +145,7 @@ static char *find_char_unquote (char *string, int stop1, int stop2,
 /* Read in all the makefiles and return the chain of their names.  */
 
 struct dep *
-read_all_makefiles (char **makefiles)
+read_all_makefiles (const char **makefiles)
 {
   unsigned int num_makefiles = 0;
 
@@ -181,7 +179,7 @@ read_all_makefiles (char **makefiles)
        MAKEFILES is updated for finding remaining tokens.  */
     p = value;
 
-    while ((name = find_next_token (&p, &length)) != 0)
+    while ((name = find_next_token ((const char **)&p, &length)) != 0)
       {
 	if (*p != '\0')
 	  *p++ = '\0';
@@ -248,7 +246,7 @@ read_all_makefiles (char **makefiles)
 	  for (p = default_makefiles; *p != 0; ++p)
 	    {
 	      struct dep *d = alloc_dep ();
-	      d->file = enter_file (*p);
+	      d->file = enter_file (strcache_add (*p));
 	      d->file->dontcare = 1;
 	      /* Tell update_goal_chain to bail out as soon as this file is
 		 made, and main not to die if we can't make this file.  */
@@ -296,17 +294,17 @@ restore_conditionals (struct conditionals *saved)
 }
 
 static int
-eval_makefile (char *filename, int flags)
+eval_makefile (const char *filename, int flags)
 {
   struct dep *deps;
   struct ebuffer ebuf;
   const struct floc *curfile;
   char *expanded = 0;
-  char *included = 0;
   int makefile_errno;
   int r;
 
-  ebuf.floc.filenm = strcache_add (filename);
+  filename = strcache_add (filename);
+  ebuf.floc.filenm = filename;
   ebuf.floc.lineno = 1;
 
   if (ISDB (DB_VERBOSE))
@@ -343,21 +341,17 @@ eval_makefile (char *filename, int flags)
      search the included makefile search path for this makefile.  */
   if (ebuf.fp == 0 && (flags & RM_INCLUDED) && *filename != '/')
     {
-      register unsigned int i;
+      unsigned int i;
       for (i = 0; include_directories[i] != 0; ++i)
 	{
-	  included = concat (include_directories[i], "/", filename);
+	  const char *included = concat (include_directories[i], "/", filename);
 	  ebuf.fp = fopen (included, "r");
 	  if (ebuf.fp)
 	    {
-	      filename = included;
+	      filename = strcache_add (included);
 	      break;
 	    }
-          free (included);
 	}
-      /* If we're not using it, we already freed it above.  */
-      if (filename != included)
-        included = 0;
     }
 
   /* Add FILENAME to the chain of read makefiles.  */
@@ -366,7 +360,7 @@ eval_makefile (char *filename, int flags)
   read_makefiles = deps;
   deps->file = lookup_file (filename);
   if (deps->file == 0)
-    deps->file = enter_file (xstrdup (filename));
+    deps->file = enter_file (filename);
   filename = deps->file->name;
   deps->changed = flags;
   if (flags & RM_DONTCARE)
@@ -374,8 +368,6 @@ eval_makefile (char *filename, int flags)
 
   if (expanded)
     free (expanded);
-  if (included)
-    free (included);
 
   /* If the makefile can't be found at all, give up entirely.  */
 
@@ -464,7 +456,8 @@ eval (struct ebuffer *ebuf, int set_default)
   struct dep *deps = 0;
   long nlines = 0;
   int two_colon = 0;
-  char *pattern = 0, *pattern_percent;
+  const char *pattern = 0;
+  const char *pattern_percent;
   struct floc *fstart;
   struct floc fi;
 
@@ -481,7 +474,7 @@ eval (struct ebuffer *ebuf, int set_default)
       filenames = 0;							      \
       commands_idx = 0;							      \
       no_targets = 0;                                                         \
-      if (pattern) { free(pattern); pattern = 0; }                            \
+      pattern = 0;                                                            \
     } while (0)
 
   pattern_percent = 0;
@@ -708,14 +701,15 @@ eval (struct ebuffer *ebuf, int set_default)
               else
                 {
                   unsigned int l;
+                  const char *cp;
                   char *ap;
 
                   /* Expand the line so we can use indirect and constructed
                      variable names in an export command.  */
-                  p2 = ap = allocated_variable_expand (p2);
+                  cp = ap = allocated_variable_expand (p2);
 
-                  for (p = find_next_token (&p2, &l); p != 0;
-                       p = find_next_token (&p2, &l))
+                  for (p = find_next_token (&cp, &l); p != 0;
+                       p = find_next_token (&cp, &l))
                     {
                       v = lookup_variable (p, l);
                       if (v == 0)
@@ -737,14 +731,15 @@ eval (struct ebuffer *ebuf, int set_default)
             {
               unsigned int l;
               struct variable *v;
+              const char *cp;
               char *ap;
 
               /* Expand the line so we can use indirect and constructed
                  variable names in an unexport command.  */
-              p2 = ap = allocated_variable_expand (p2);
+              cp = ap = allocated_variable_expand (p2);
 
-              for (p = find_next_token (&p2, &l); p != 0;
-                   p = find_next_token (&p2, &l))
+              for (p = find_next_token (&cp, &l); p != 0;
+                   p = find_next_token (&cp, &l))
                 {
                   v = lookup_variable (p, l);
                   if (v == 0)
@@ -761,14 +756,15 @@ eval (struct ebuffer *ebuf, int set_default)
  skip_conditionals:
       if (word1eq ("vpath"))
 	{
+          const char *cp;
 	  char *vpat;
 	  unsigned int l;
-	  p2 = variable_expand (p2);
-	  p = find_next_token (&p2, &l);
+	  cp = variable_expand (p2);
+	  p = find_next_token (&cp, &l);
 	  if (p != 0)
 	    {
 	      vpat = savestring (p, l);
-	      p = find_next_token (&p2, &l);
+	      p = find_next_token (&cp, &l);
 	      /* No searchpath means remove all previous
 		 selective VPATH's with the same pattern.  */
 	    }
@@ -822,7 +818,7 @@ eval (struct ebuffer *ebuf, int set_default)
 	  while (files != 0)
 	    {
 	      struct nameseq *next = files->next;
-	      char *name = files->name;
+	      const char *name = files->name;
               int r;
 
 	      free (files);
@@ -832,7 +828,6 @@ eval (struct ebuffer *ebuf, int set_default)
                                         | (noerror ? RM_DONTCARE : 0)));
 	      if (!r && !noerror)
                 error (fstart, "%s: %s", name, strerror (errno));
-              free (name);
 	    }
 
 	  /* Restore conditional state.  */
@@ -1148,8 +1143,8 @@ eval (struct ebuffer *ebuf, int set_default)
               fatal (fstart, _("missing target pattern"));
             else if (target->next != 0)
               fatal (fstart, _("multiple target patterns"));
+            pattern_percent = find_percent_cached (&target->name);
             pattern = target->name;
-            pattern_percent = find_percent (pattern);
             if (pattern_percent == 0)
               fatal (fstart, _("target pattern contains no `%%'"));
             free (target);
@@ -1166,7 +1161,7 @@ eval (struct ebuffer *ebuf, int set_default)
           {
             /* Put all the prerequisites here; they'll be parsed later.  */
             deps = alloc_dep ();
-            deps->name = savestring (beg, end - beg + 1);
+            deps->name = strcache_add_len (beg, end - beg + 1);
           }
         else
           deps = 0;
@@ -1208,7 +1203,7 @@ eval (struct ebuffer *ebuf, int set_default)
 
         if (**default_goal_name == '\0' && set_default)
           {
-            char* name;
+            const char *name;
             struct dep *d;
             struct nameseq *t = filenames;
 
@@ -1769,9 +1764,9 @@ record_target_var (struct nameseq *filenames, char *defn,
   for (; filenames != 0; filenames = nextf)
     {
       struct variable *v;
-      register char *name = filenames->name;
-      char *fname;
-      char *percent;
+      const char *name = filenames->name;
+      const char *fname;
+      const char *percent;
       struct pattern_var *p;
 
       nextf = filenames->next;
@@ -1779,7 +1774,7 @@ record_target_var (struct nameseq *filenames, char *defn,
 
       /* If it's a pattern target, then add it to the pattern-specific
          variable list.  */
-      percent = find_percent (name);
+      percent = find_percent_cached (&name);
       if (percent)
         {
           /* Get a reference for this pattern-specific variable struct.  */
@@ -1807,7 +1802,7 @@ record_target_var (struct nameseq *filenames, char *defn,
              this situation.  */
           f = lookup_file (name);
           if (!f)
-            f = enter_file (name);
+            f = enter_file (strcache_add (name));
           else if (f->double_colon)
             f = f->double_colon;
 
@@ -1844,10 +1839,6 @@ record_target_var (struct nameseq *filenames, char *defn,
               v->append = 0;
             }
         }
-
-      /* Free name if not needed further.  */
-      if (name != fname && (name < fname || name > fname + strlen (fname)))
-        free (name);
     }
 }
 
@@ -1863,15 +1854,16 @@ record_target_var (struct nameseq *filenames, char *defn,
    that are not incorporated into other data structures.  */
 
 static void
-record_files (struct nameseq *filenames, char *pattern, char *pattern_percent,
-              struct dep *deps, unsigned int cmds_started, char *commands,
+record_files (struct nameseq *filenames, const char *pattern,
+              const char *pattern_percent, struct dep *deps,
+              unsigned int cmds_started, char *commands,
               unsigned int commands_idx, int two_colon,
               const struct floc *flocp)
 {
   struct nameseq *nextf;
   int implicit = 0;
   unsigned int max_targets = 0, target_idx = 0;
-  char **targets = 0, **target_percents = 0;
+  const char **targets = 0, **target_percents = 0;
   struct commands *cmds;
 
   /* If we've already snapped deps, that means we're in an eval being
@@ -1894,10 +1886,10 @@ record_files (struct nameseq *filenames, char *pattern, char *pattern_percent,
 
   for (; filenames != 0; filenames = nextf)
     {
-      char *name = filenames->name;
+      const char *name = filenames->name;
       struct file *f;
       struct dep *this = 0;
-      char *implicit_percent;
+      const char *implicit_percent;
 
       nextf = filenames->next;
       free (filenames);
@@ -1910,17 +1902,17 @@ record_files (struct nameseq *filenames, char *pattern, char *pattern_percent,
       else if (streq (name, ".SECONDEXPANSION"))
         second_expansion = 1;
 
-      implicit_percent = find_percent (name);
+      implicit_percent = find_percent_cached (&name);
       implicit |= implicit_percent != 0;
 
-      if (implicit && pattern != 0)
-	fatal (flocp, _("mixed implicit and static pattern rules"));
+      if (implicit)
+        {
+          if (pattern != 0)
+            fatal (flocp, _("mixed implicit and static pattern rules"));
 
-      if (implicit && implicit_percent == 0)
-	fatal (flocp, _("mixed implicit and normal rules"));
+          if (implicit_percent == 0)
+            fatal (flocp, _("mixed implicit and normal rules"));
 
-      if (implicit)
-	{
 	  if (targets == 0)
 	    {
 	      max_targets = 5;
@@ -1960,7 +1952,7 @@ record_files (struct nameseq *filenames, char *pattern, char *pattern_percent,
 	{
 	  /* Single-colon.  Combine these dependencies
 	     with others in file's existing record, if any.  */
-	  f = enter_file (name);
+	  f = enter_file (strcache_add (name));
 
 	  if (f->double_colon)
 	    fatal (flocp,
@@ -2066,7 +2058,7 @@ record_files (struct nameseq *filenames, char *pattern, char *pattern_percent,
 	  if (f != 0 && f->is_target && !f->double_colon)
 	    fatal (flocp,
                    _("target file `%s' has both : and :: entries"), f->name);
-	  f = enter_file (name);
+	  f = enter_file (strcache_add (name));
 	  /* If there was an existing entry and it was a double-colon entry,
 	     enter_file will have returned a new one, making it the prev
 	     pointer of the old one, and setting its double_colon pointer to
@@ -2085,25 +2077,19 @@ record_files (struct nameseq *filenames, char *pattern, char *pattern_percent,
          commands.  */
       if (pattern)
         {
-          static char *percent = "%";
+          static const char *percent = "%";
           char *buffer = variable_expand ("");
-          char *o = patsubst_expand (buffer, name, pattern, percent,
-                                     pattern_percent+1, percent+1);
-          f->stem = savestring (buffer, o - buffer);
+          char *o = patsubst_expand_pat (buffer, name, pattern, percent,
+                                         pattern_percent+1, percent+1);
+          f->stem = strcache_add_len (buffer, o - buffer);
           if (this)
             {
               this->staticpattern = 1;
-              this->stem = xstrdup (f->stem);
+              this->stem = f->stem;
             }
         }
 
-      /* Free name if not needed further.  */
-      if (f != 0 && name != f->name
-	  && (name < f->name || name > f->name + strlen (f->name)))
-	{
-	  free (name);
-	  name = f->name;
-	}
+      name = f->name;
 
       /* If this target is a default target, update DEFAULT_GOAL_FILE.  */
       if (streq (*default_goal_name, name)
@@ -2114,12 +2100,10 @@ record_files (struct nameseq *filenames, char *pattern, char *pattern_percent,
 
   if (implicit)
     {
-      targets[target_idx] = 0;
-      target_percents[target_idx] = 0;
       if (deps)
         deps->need_2nd_expansion = second_expansion;
-      create_pattern_rule (targets, target_percents, two_colon, deps, cmds, 1);
-      free (target_percents);
+      create_pattern_rule (targets, target_percents, target_idx,
+                           two_colon, deps, cmds, 1);
     }
 }
 
@@ -2137,7 +2121,7 @@ find_char_unquote (char *string, int stop1, int stop2, int blank,
                    int ignorevars)
 {
   unsigned int string_len = 0;
-  register char *p = string;
+  char *p = string;
 
   if (ignorevars)
     ignorevars = '$';
@@ -2230,6 +2214,82 @@ find_percent (char *pattern)
 {
   return find_char_unquote (pattern, '%', 0, 0, 0);
 }
+
+/* Search STRING for an unquoted % and handle quoting.  Returns a pointer to
+   the % or NULL if no % was found.
+   This version is used with strings in the string cache: if there's a need to
+   modify the string a new version will be added to the string cache and
+   *STRING will be set to that.  */
+
+const char *
+find_percent_cached (const char **string)
+{
+  const char *p = *string;
+  char *new = 0;
+  int slen;
+
+  /* If the first char is a % return now.  This lets us avoid extra tests
+     inside the loop.  */
+  if (*p == '%')
+    return p;
+
+  while (1)
+    {
+      while (*p != '\0' && *p != '%')
+        ++p;
+
+      if (*p == '\0')
+        break;
+
+      /* See if this % is escaped with a backslash; if not we're done.  */
+      if (p[-1] != '\\')
+        break;
+
+      {
+        /* Search for more backslashes.  */
+        char *pv;
+        int i = -2;
+
+        while (&p[i] >= *string && p[i] == '\\')
+          --i;
+        ++i;
+
+        /* At this point we know we'll need to allocate a new string.
+           Make a copy if we haven't yet done so.  */
+        if (! new)
+          {
+            slen = strlen (*string);
+            new = alloca (slen + 1);
+            memcpy (new, *string, slen + 1);
+            p = new + (p - *string);
+            *string = new;
+          }
+
+        /* At this point *string, p, and new all point into the same string.
+           Get a non-const version of p so we can modify new.  */
+        pv = new + (p - *string);
+
+        /* The number of backslashes is now -I.
+           Copy P over itself to swallow half of them.  */
+        memmove (&pv[i], &pv[i/2], (slen - (pv - new)) - (i/2) + 1);
+        p += i/2;
+
+        /* If the backslashes quoted each other; the % was unquoted.  */
+        if (i % 2 == 0)
+          break;
+      }
+    }
+
+  /* If we had to change STRING, add it to the strcache.  */
+  if (new)
+    {
+      *string = strcache_add (*string);
+      p = *string + (p - new);
+    }
+
+  /* If we didn't find a %, return NULL.  Otherwise return a ptr to it.  */
+  return (*p == '\0') ? NULL : p;
+}
 
 /* Parse a string into a sequence of filenames represented as a
    chain of struct nameseq's in reverse order and return that chain.
@@ -2250,8 +2310,6 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
   struct nameseq *new = 0;
   struct nameseq *new1, *lastnew1;
   char *p = *stringp;
-  char *q;
-  char *name;
 
 #ifdef VMS
 # define VMS_COMMA ','
@@ -2261,6 +2319,9 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
 
   while (1)
     {
+      const char *name;
+      char *q;
+
       /* Skip whitespace; see if any more names are left.  */
       p = next_token (p);
       if (*p == '\0')
@@ -2268,7 +2329,7 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
       if (*p == stopchar)
 	break;
 
-      /* Yes, find end of next name.  */
+      /* There are, so find the end of the next name.  */
       q = p;
       p = find_char_unquote (q, stopchar, VMS_COMMA, 1, 0);
 #ifdef VMS
@@ -2280,9 +2341,7 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
       if (stopchar == ':' && p && *p == ':'
           && !(isspace ((unsigned char)p[1]) || !p[1]
                || isspace ((unsigned char)p[-1])))
-      {
 	p = find_char_unquote (p+1, stopchar, VMS_COMMA, 1, 0);
-      }
 #endif
 #ifdef HAVE_DOS_PATHS
     /* For DOS paths, skip a "C:\..." or a "C:/..." until we find the
@@ -2316,14 +2375,12 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
 
       if (q == p)
 	/* ".///" was stripped to "". */
-#ifdef VMS
+#if defined(VMS)
 	continue;
+#elif defined(_AMIGA)
+        name = "";
 #else
-#ifdef _AMIGA
-	name = savestring ("", 0);
-#else
-	name = savestring ("./", 2);
-#endif
+	name = "./";
 #endif
       else
 #ifdef VMS
@@ -2347,11 +2404,11 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
 		}
 	      *q2++ = *q1++;
 	    }
-	  name = savestring (qbase, p1 - qbase);
+	  name = strcache_add_len (qbase, p1 - qbase);
 	  free (qbase);
 	}
 #else
-	name = savestring (q, p - q);
+	name = strcache_add_len (q, p - q);
 #endif
 
       /* Add it to the front of the chain.  */
@@ -2407,7 +2464,6 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
 		/* N was just "lib(", part of something like "lib( a b)".
 		   Edit it out of the chain and free its storage.  */
 		lastn->next = n->next;
-		free (n->name);
 		free (n);
 		/* LASTN->next is the new stopping elt for the loop below.  */
 		n = lastn->next;
@@ -2415,9 +2471,7 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
 	    else
 	      {
 		/* Replace N's name with the full archive reference.  */
-		name = concat (libname, paren, ")");
-		free (n->name);
-		n->name = name;
+		n->name = strcache_add (concat (libname, paren, ")"));
 	      }
 
 	    if (new1->name[1] == '\0')
@@ -2430,15 +2484,12 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
 		  lastnew1->next = new1->next;
 		lastn = new1;
 		new1 = new1->next;
-		free (lastn->name);
 		free (lastn);
 	      }
 	    else
 	      {
 		/* Replace also NEW1->name, which already has closing `)'.  */
-		name = concat (libname, new1->name, "");
-		free (new1->name);
-		new1->name = name;
+		new1->name = strcache_add (concat (libname, new1->name, ""));
 		new1 = new1->next;
 	      }
 
@@ -2448,9 +2499,7 @@ parse_file_seq (char **stringp, int stopchar, unsigned int size, int strip)
 
 	    while (new1 != n)
 	      {
-		name = concat (libname, new1->name, ")");
-		free (new1->name);
-		new1->name = name;
+		new1->name = strcache_add (concat (libname, new1->name, ")"));
 		lastnew1 = new1;
 		new1 = new1->next;
 	      }
@@ -2818,104 +2867,112 @@ get_next_mword (char *buffer, char *delim, char **startp, unsigned int *length)
    from the arguments and the default list.  */
 
 void
-construct_include_path (char **arg_dirs)
+construct_include_path (const char **arg_dirs)
 {
-  register unsigned int i;
 #ifdef VAXC		/* just don't ask ... */
   stat_t stbuf;
 #else
   struct stat stbuf;
 #endif
-  /* Table to hold the dirs.  */
+  const char **dirs;
+  const char **cpp;
+  unsigned int idx;
 
-  unsigned int defsize = (sizeof (default_include_directories)
-                          / sizeof (default_include_directories[0]));
-  unsigned int max = 5;
-  char **dirs = xmalloc ((5 + defsize) * sizeof (char *));
-  unsigned int idx = 0;
+  /* Compute the number of pointers we need in the table.  */
+  idx = sizeof (default_include_directories) / sizeof (const char *);
+  if (arg_dirs)
+    for (cpp = arg_dirs; *cpp != 0; ++cpp)
+      ++idx;
 
 #ifdef  __MSDOS__
-  defsize++;
+  /* Add one for $DJDIR.  */
+  ++idx;
 #endif
 
+  dirs = xmalloc (idx * sizeof (const char *));
+
+  idx = 0;
+  max_incl_len = 0;
+
   /* First consider any dirs specified with -I switches.
-     Ignore dirs that don't exist.  */
+     Ignore any that don't exist.  Remember the maximum string length.  */
 
-  if (arg_dirs != 0)
+  if (arg_dirs)
     while (*arg_dirs != 0)
       {
-	char *dir = *arg_dirs++;
+	const char *dir = *(arg_dirs++);
+        char *expanded = 0;
         int e;
 
 	if (dir[0] == '~')
 	  {
-	    char *expanded = tilde_expand (dir);
+	    expanded = tilde_expand (dir);
 	    if (expanded != 0)
 	      dir = expanded;
 	  }
 
         EINTRLOOP (e, stat (dir, &stbuf));
 	if (e == 0 && S_ISDIR (stbuf.st_mode))
-	  {
-	    if (idx == max - 1)
-	      {
-		max += 5;
-		dirs = xrealloc (dirs, (max + defsize) * sizeof (char *));
-	      }
-	    dirs[idx++] = dir;
-	  }
-	else if (dir != arg_dirs[-1])
-	  free (dir);
+          {
+            unsigned int len = strlen (dir);
+            /* If dir name is written with trailing slashes, discard them.  */
+            while (len > 1 && dir[len - 1] == '/')
+              --len;
+            if (len > max_incl_len)
+              max_incl_len = len;
+            dirs[idx++] = strcache_add_len (dir, len);
+          }
+
+	if (expanded)
+	  free (expanded);
       }
 
-  /* Now add at the end the standard default dirs.  */
+  /* Now add the standard default dirs at the end.  */
 
 #ifdef  __MSDOS__
   {
-    /* The environment variable $DJDIR holds the root of the
-       DJGPP directory tree; add ${DJDIR}/include.  */
+    /* The environment variable $DJDIR holds the root of the DJGPP directory
+       tree; add ${DJDIR}/include.  */
     struct variable *djdir = lookup_variable ("DJDIR", 5);
 
     if (djdir)
       {
-	char *defdir = xmalloc (strlen (djdir->value) + 8 + 1);
+        unsigned int len = strlen (djdir->value) + 8;
+	char *defdir = alloca (len + 1);
 
 	strcat (strcpy (defdir, djdir->value), "/include");
-	dirs[idx++] = defdir;
+	dirs[idx++] = strcache_add (defdir);
+
+        if (len > max_incl_len)
+          max_incl_len = len;
       }
   }
 #endif
 
-  for (i = 0; default_include_directories[i] != 0; ++i)
+  for (cpp = default_include_directories; *cpp != 0; ++cpp)
     {
       int e;
 
-      EINTRLOOP (e, stat (default_include_directories[i], &stbuf));
+      EINTRLOOP (e, stat (*cpp, &stbuf));
       if (e == 0 && S_ISDIR (stbuf.st_mode))
-        dirs[idx++] = default_include_directories[i];
+        {
+          unsigned int len = strlen (*cpp);
+          /* If dir name is written with trailing slashes, discard them.  */
+          while (len > 1 && (*cpp)[len - 1] == '/')
+            --len;
+          if (len > max_incl_len)
+            max_incl_len = len;
+          dirs[idx++] = strcache_add_len (*cpp, len - 1);
+        }
     }
 
   dirs[idx] = 0;
 
-  /* Now compute the maximum length of any name in it. Also add each
-     dir to the .INCLUDE_DIRS variable.  */
+  /* Now add each dir to the .INCLUDE_DIRS variable.  */
 
-  max_incl_len = 0;
-  for (i = 0; i < idx; ++i)
-    {
-      unsigned int len = strlen (dirs[i]);
-      /* If dir name is written with a trailing slash, discard it.  */
-      if (dirs[i][len - 1] == '/')
-	/* We can't just clobber a null in because it may have come from
-	   a literal string and literal strings may not be writable.  */
-	dirs[i] = savestring (dirs[i], len - 1);
-      if (len > max_incl_len)
-	max_incl_len = len;
-
-      /* Append to .INCLUDE_DIRS.   */
-      do_variable_definition (NILF, ".INCLUDE_DIRS", dirs[i],
-                              o_default, f_append, 0);
-    }
+  for (cpp = dirs; *cpp != 0; ++cpp)
+    do_variable_definition (NILF, ".INCLUDE_DIRS", *cpp,
+                            o_default, f_append, 0);
 
   include_directories = dirs;
 }
@@ -2924,7 +2981,7 @@ construct_include_path (char **arg_dirs)
    Return a newly malloc'd string or 0.  */
 
 char *
-tilde_expand (char *name)
+tilde_expand (const char *name)
 {
 #ifndef VMS
   if (name[1] == '/' || name[1] == '\0')
@@ -2949,7 +3006,7 @@ tilde_expand (char *name)
 	  free (home_dir);
 	  home_dir = getenv ("HOME");
 	}
-#if !defined(_AMIGA) && !defined(WINDOWS32)
+# if !defined(_AMIGA) && !defined(WINDOWS32)
       if (home_dir == 0 || home_dir[0] == '\0')
 	{
 	  extern char *getlogin ();
@@ -2962,16 +3019,16 @@ tilde_expand (char *name)
 		home_dir = p->pw_dir;
 	    }
 	}
-#endif /* !AMIGA && !WINDOWS32 */
+# endif /* !AMIGA && !WINDOWS32 */
       if (home_dir != 0)
 	{
-	  char *new = concat (home_dir, "", name + 1);
+	  char *new = xstrdup (concat (home_dir, "", name + 1));
 	  if (is_variable)
 	    free (home_dir);
 	  return new;
 	}
     }
-#if !defined(_AMIGA) && !defined(WINDOWS32)
+# if !defined(_AMIGA) && !defined(WINDOWS32)
   else
     {
       struct passwd *pwent;
@@ -2984,12 +3041,12 @@ tilde_expand (char *name)
 	  if (userend == 0)
 	    return xstrdup (pwent->pw_dir);
 	  else
-	    return concat (pwent->pw_dir, "/", userend + 1);
+	    return xstrdup (concat (pwent->pw_dir, "/", userend + 1));
 	}
       else if (userend != 0)
 	*userend = '/';
     }
-#endif /* !AMIGA && !WINDOWS32 */
+# endif /* !AMIGA && !WINDOWS32 */
 #endif /* !VMS */
   return 0;
 }
@@ -3007,9 +3064,9 @@ tilde_expand (char *name)
 struct nameseq *
 multi_glob (struct nameseq *chain, unsigned int size)
 {
-  extern void dir_setup_glob ();
-  register struct nameseq *new = 0;
-  register struct nameseq *old;
+  void dir_setup_glob (glob_t *);
+  struct nameseq *new = 0;
+  struct nameseq *old;
   struct nameseq *nexto;
   glob_t gl;
 
@@ -3017,44 +3074,37 @@ multi_glob (struct nameseq *chain, unsigned int size)
 
   for (old = chain; old != 0; old = nexto)
     {
+      const char *gname;
 #ifndef NO_ARCHIVES
-      char *memname;
+      char *arname = 0;
+      char *memname = 0;
 #endif
-
       nexto = old->next;
+      gname = old->name;
 
-      if (old->name[0] == '~')
+      if (gname[0] == '~')
 	{
 	  char *newname = tilde_expand (old->name);
 	  if (newname != 0)
-	    {
-	      free (old->name);
-	      old->name = newname;
-	    }
+            gname = newname;
 	}
 
 #ifndef NO_ARCHIVES
-      if (ar_name (old->name))
+      if (ar_name (gname))
 	{
-	  /* OLD->name is an archive member reference.
-	     Replace it with the archive file name,
-	     and save the member name in MEMNAME.
-	     We will glob on the archive name and then
-	     reattach MEMNAME later.  */
-	  char *arname;
-	  ar_parse_name (old->name, &arname, &memname);
-	  free (old->name);
-	  old->name = arname;
+	  /* OLD->name is an archive member reference.  Replace it with the
+	     archive file name, and save the member name in MEMNAME.  We will
+	     glob on the archive name and then reattach MEMNAME later.  */
+	  ar_parse_name (gname, &arname, &memname);
+	  gname = arname;
 	}
-      else
-	memname = 0;
 #endif /* !NO_ARCHIVES */
 
-      switch (glob (old->name, GLOB_NOCHECK|GLOB_ALTDIRFUNC, NULL, &gl))
+      switch (glob (gname, GLOB_NOCHECK|GLOB_ALTDIRFUNC, NULL, &gl))
 	{
 	case 0:			/* Success.  */
 	  {
-	    register int i = gl.gl_pathc;
+	    int i = gl.gl_pathc;
 	    while (i-- > 0)
 	      {
 #ifndef NO_ARCHIVES
@@ -3063,21 +3113,22 @@ multi_glob (struct nameseq *chain, unsigned int size)
 		    /* Try to glob on MEMNAME within the archive.  */
 		    struct nameseq *found
 		      = ar_glob (gl.gl_pathv[i], memname, size);
-		    if (found == 0)
+		    if (! found)
 		      {
 			/* No matches.  Use MEMNAME as-is.  */
 			unsigned int alen = strlen (gl.gl_pathv[i]);
 			unsigned int mlen = strlen (memname);
+                        char *name;
 			struct nameseq *elt = xmalloc (size);
-                        if (size > sizeof (struct nameseq))
-                          memset (((char *)elt)+sizeof (struct nameseq), '\0',
-                                  size - sizeof (struct nameseq));
-			elt->name = xmalloc (alen + 1 + mlen + 2);
-			memcpy (elt->name, gl.gl_pathv[i], alen);
-			elt->name[alen] = '(';
-			memcpy (&elt->name[alen + 1], memname, mlen);
-			elt->name[alen + 1 + mlen] = ')';
-			elt->name[alen + 1 + mlen + 1] = '\0';
+                        memset (elt, '\0', size);
+
+                        name = alloca (alen + 1 + mlen + 2);
+			memcpy (name, gl.gl_pathv[i], alen);
+			name[alen] = '(';
+			memcpy (name+alen+1, memname, mlen);
+			name[alen + 1 + mlen] = ')';
+			name[alen + 1 + mlen + 1] = '\0';
+                        elt->name = strcache_add (name);
 			elt->next = new;
 			new = elt;
 		      }
@@ -3093,23 +3144,18 @@ multi_glob (struct nameseq *chain, unsigned int size)
 			f->next = new;
 			new = found;
 		      }
-
-		    free (memname);
 		  }
 		else
 #endif /* !NO_ARCHIVES */
 		  {
 		    struct nameseq *elt = xmalloc (size);
-                    if (size > sizeof (struct nameseq))
-                      memset (((char *)elt)+sizeof (struct nameseq), '\0',
-                              size - sizeof (struct nameseq));
-		    elt->name = xstrdup (gl.gl_pathv[i]);
+                    memset (elt, '\0', size);
+		    elt->name = strcache_add (gl.gl_pathv[i]);
 		    elt->next = new;
 		    new = elt;
 		  }
 	      }
 	    globfree (&gl);
-	    free (old->name);
 	    free (old);
 	    break;
 	  }
@@ -3123,6 +3169,11 @@ multi_glob (struct nameseq *chain, unsigned int size)
 	  new = old;
 	  break;
 	}
+
+#ifndef NO_ARCHIVES
+      if (arname)
+        free (arname);
+#endif
     }
 
   return new;