Move levels to its own pass

The optimizer needs to know the embeddeng level of the various
definitions. Previously, this was computed in the offsets pass, but if
the optimizer removes unused variables, the offsets could change. The
levels must be computed before optimizations, but offsets must be
computers.

So split levels to its own pass that runs before the optimizer.

5 files changed, 79 insertions, 20 deletions

diff --git a/Makefile b/Makefile
index 293a9d8..f1249c2 100644
--- a/Makefile
+++ b/Makefile
@@ -15,6 +15,7 @@ OBJS =				\
 	switch.o		\
 	graph.o			\
 	optimize.o		\
+	levels.o		\
 	offsets.o		\
 	init-check.o		\
 	initialized-check.o 	\
diff --git a/ast.h b/ast.h
index 0cd08ff..ad532d1 100644
--- a/ast.h
+++ b/ast.h
@@ -1463,9 +1463,10 @@ gboolean type_check     (ast_t           *ast);
 gboolean mark_constants (ast_t           *ast);
 gboolean switch_check   (ast_t           *ast);
 gboolean graph          (ast_t           *ast);
-gboolean optimize       (ast_t           *ast);
 gboolean init_check     (ast_t           *ast);
 gboolean return_check   (ast_t           *ast);
+gboolean levels		(ast_t		 *ast);
+gboolean optimize       (ast_t           *ast);
 gboolean offsets        (ast_t           *ast);
 void     interpret      (ast_t           *ast);
 
diff --git a/levels.c b/levels.c
new file mode 100644
index 0000000..5399bf1
--- /dev/null
+++ b/levels.c
@@ -0,0 +1,67 @@
+/* Ninja
+ * Copyright 2007, Soren Sandmann Pedersen
+ *
+ * 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 "ast.h"
+
+static void
+do_levels (ast_t *ast, int level)
+{
+    GList *list;
+
+    if (ast_is (ast, AST_DEFINITION, AST_FUNCTION_DEFINITION))
+    {
+	ast_function_definition_t *function = &ast->definition.function;
+
+	function->level = level++;
+    }
+    else if (ast_is (ast, AST_DEFINITION, AST_CLASS_DEFINITION))
+    {
+	ast_class_definition_t *class = &ast->definition.class;
+
+	class->level = level++;
+    }
+    else if (ast->common.type == AST_EXPRESSION)
+    {
+	ast_expression_t *expr = &ast->expression;
+
+	expr->common.level = level;
+    }
+    else if (ast_is (ast, AST_DEFINITION, AST_LABEL_DEFINITION))
+    {
+	ast_label_definition_t *label = &(ast->definition.label);
+
+	label->level = level;
+    }
+    else if (ast_is (ast, AST_DEFINITION, AST_VARIABLE_DEFINITION))
+    {
+	ast_variable_definition_t *variable = &(ast->definition.variable);
+
+	variable->level = level;
+    }
+    
+    for (list = ast->common.children->head; list; list = list->next)
+	do_levels (list->data, level);
+}
+
+gboolean
+levels (ast_t *ast)
+{
+    do_levels (ast, 0);
+    
+    return TRUE;
+}
diff --git a/main.c b/main.c
index 6140f62..8ab9f25 100644
--- a/main.c
+++ b/main.c
@@ -58,12 +58,15 @@ compile (const char *input, gboolean do_optimize)
     if (!return_check (ast))
 	return NULL;
 
-    if (!offsets (ast))
+    if (!levels (ast))
 	return NULL;
 
     if (do_optimize && !optimize (ast))
 	return NULL;
 
+    if (!offsets (ast))
+	return NULL;
+
     return ast;
 }
 
diff --git a/offsets.c b/offsets.c
index f6cd38d..93ead6f 100644
--- a/offsets.c
+++ b/offsets.c
@@ -27,7 +27,7 @@ list_def (gpointer key, gpointer value, gpointer data)
 }
 
 static int
-assign_offsets (symbol_table_t *symbols, int offset, int level, int *max)
+assign_offsets (symbol_table_t *symbols, int offset, int *max)
 {
     GPtrArray *definitions = g_ptr_array_new ();
     int i;
@@ -47,7 +47,6 @@ assign_offsets (symbol_table_t *symbols, int offset, int level, int *max)
 		offset += (size - offset % size);
 
 	    definition->variable.offset = offset;
-	    definition->variable.level = level;
 
 	    offset += size;
 	}
@@ -62,7 +61,7 @@ assign_offsets (symbol_table_t *symbols, int offset, int level, int *max)
 }
 
 static void
-do_offsets (ast_t *ast, int offset, int level, int *max)
+do_offsets (ast_t *ast, int offset, int *max)
 {
     GList *list;
     symbol_table_t *symbols = NULL;
@@ -85,7 +84,6 @@ do_offsets (ast_t *ast, int offset, int level, int *max)
 	if (0) /* FIXME: For now we don't support virtual methods */
 	    offset += sizeof (gpointer);	 /* The vtable pointer */
 
-	class->level = level++;
 	class->env_size = offset;
 
 	max = &(class->env_size);
@@ -100,17 +98,10 @@ do_offsets (ast_t *ast, int offset, int level, int *max)
 						 * the old env,
 						 * the return address */
 
-	function->level = level++;
 	function->env_size = offset;
 
 	max = &(function->env_size);
     }
-    else if (ast_is (ast, AST_DEFINITION, AST_LABEL_DEFINITION))
-    {
-	ast_label_definition_t *label = &(ast->definition.label);
-
-	label->level = level;
-    }
     else if (ast->common.type == AST_PROGRAM)
     {
 	ast_program_t *program = &(ast->program);
@@ -121,22 +112,18 @@ do_offsets (ast_t *ast, int offset, int level, int *max)
 
 	max = &(program->env_size);
     }
-    else if (ast->common.type == AST_EXPRESSION)
-    {
-	ast->expression.common.level = level;
-    }
 
     if (symbols)
-	offset = assign_offsets (symbols, offset, level, max);
+	offset = assign_offsets (symbols, offset, max);
 
     for (list = ast->common.children->head; list != NULL; list = list->next)
-	do_offsets (list->data, offset, level, max);
+	do_offsets (list->data, offset, max);
 }
 
 gboolean
 offsets (ast_t *ast)
 {
-    do_offsets (ast, 0, 0, NULL);
+    do_offsets (ast, 0, NULL);
 
     /* The offsets pass can never fail */
     return TRUE;