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, 28 insertions, 27 deletions

diff --git a/variable.c b/variable.c
index 8a82a3f..b564614 100644
--- a/variable.c
+++ b/variable.c
@@ -42,7 +42,7 @@ static struct pattern_var *last_pattern_var;
 /* Create a new pattern-specific variable struct.  */
 
 struct pattern_var *
-create_pattern_var (char *target, char *suffix)
+create_pattern_var (const char *target, const char *suffix)
 {
   register struct pattern_var *p = xmalloc (sizeof (struct pattern_var));
 
@@ -63,14 +63,14 @@ create_pattern_var (char *target, char *suffix)
 /* Look up a target in the pattern-specific variable list.  */
 
 static struct pattern_var *
-lookup_pattern_var (struct pattern_var *start, char *target)
+lookup_pattern_var (struct pattern_var *start, const char *target)
 {
   struct pattern_var *p;
   unsigned int targlen = strlen(target);
 
   for (p = start ? start->next : pattern_vars; p != 0; p = p->next)
     {
-      char *stem;
+      const char *stem;
       unsigned int stemlen;
 
       if (p->len > targlen)
@@ -962,7 +962,7 @@ target_environment (struct file *file)
 		strcmp(v->name, "PATH") == 0)
 	      convert_Path_to_windows32(value, ';');
 #endif
-	    *result++ = concat (v->name, "=", value);
+	    *result++ = xstrdup (concat (v->name, "=", value));
 	    free (value);
 	  }
 	else
@@ -972,7 +972,7 @@ target_environment (struct file *file)
                 strcmp(v->name, "PATH") == 0)
               convert_Path_to_windows32(v->value, ';');
 #endif
-	    *result++ = concat (v->name, "=", v->value);
+	    *result++ = xstrdup (concat (v->name, "=", v->value));
 	  }
       }
 
@@ -990,10 +990,11 @@ target_environment (struct file *file)
 
 struct variable *
 do_variable_definition (const struct floc *flocp, const char *varname,
-                        char *value, enum variable_origin origin,
+                        const char *value, enum variable_origin origin,
                         enum variable_flavor flavor, int target_var)
 {
-  char *p, *alloc_value = NULL;
+  const char *p;
+  char *alloc_value = NULL;
   struct variable *v;
   int append = 0;
   int conditional = 0;
@@ -1058,7 +1059,8 @@ do_variable_definition (const struct floc *flocp, const char *varname,
             /* Paste the old and new values together in VALUE.  */
 
             unsigned int oldlen, vallen;
-            char *val;
+            const char *val;
+            char *tp;
 
             val = value;
             if (v->recursive)
@@ -1075,10 +1077,11 @@ do_variable_definition (const struct floc *flocp, const char *varname,
 
             oldlen = strlen (v->value);
             vallen = strlen (val);
-            p = alloca (oldlen + 1 + vallen + 1);
-            memcpy (p, v->value, oldlen);
-            p[oldlen] = ' ';
-            memcpy (&p[oldlen + 1], val, vallen + 1);
+            tp = alloca (oldlen + 1 + vallen + 1);
+            memcpy (tp, v->value, oldlen);
+            tp[oldlen] = ' ';
+            memcpy (&tp[oldlen + 1], val, vallen + 1);
+            p = tp;
           }
       }
     }
@@ -1106,20 +1109,19 @@ do_variable_definition (const struct floc *flocp, const char *varname,
       /* See if we can find "/bin/sh.exe", "/bin/sh.com", etc.  */
       if (__dosexec_find_on_path (p, NULL, shellpath))
 	{
-	  char *p;
+	  char *tp;
+
+	  for (tp = shellpath; *tp; tp++)
+            if (*tp == '\\')
+              *tp = '/';
 
-	  for (p = shellpath; *p; p++)
-	    {
-	      if (*p == '\\')
-		*p = '/';
-	    }
 	  v = define_variable_loc (varname, strlen (varname),
                                    shellpath, origin, flavor == f_recursive,
                                    flocp);
 	}
       else
 	{
-	  char *shellbase, *bslash;
+	  const char *shellbase, *bslash;
 	  struct variable *pathv = lookup_variable ("PATH", 4);
 	  char *path_string;
 	  char *fake_env[2];
@@ -1147,13 +1149,12 @@ do_variable_definition (const struct floc *flocp, const char *varname,
 	  fake_env[1] = 0;
 	  if (__dosexec_find_on_path (shellbase, fake_env, shellpath))
 	    {
-	      char *p;
+	      char *tp;
+
+	      for (tp = shellpath; *tp; tp++)
+                if (*tp == '\\')
+                  *tp = '/';
 
-	      for (p = shellpath; *p; p++)
-		{
-		  if (*p == '\\')
-		    *p = '/';
-		}
 	      v = define_variable_loc (varname, strlen (varname),
                                        shellpath, origin,
                                        flavor == f_recursive, flocp);
@@ -1473,7 +1474,7 @@ print_variable_data_base (void)
 /* Print all the local variables of FILE.  */
 
 void
-print_file_variables (struct file *file)
+print_file_variables (const struct file *file)
 {
   if (file->variables != 0)
     print_variable_set (file->variables->set, "# ");
@@ -1500,7 +1501,7 @@ sync_Path_environment (void)
    * Create something WINDOWS32 world can grok
    */
   convert_Path_to_windows32 (path, ';');
-  environ_path = concat ("PATH", "=", path);
+  environ_path = xstrdup (concat ("PATH", "=", path));
   putenv (environ_path);
   free (path);
 }