Remove redundant loads

Do breadth first of the entire program when marking variables used/unused

Don't optimize away unused function parameters

6 files changed, 62 insertions, 14 deletions

diff --git a/ast.h b/ast.h
index d8e8a97..69cc1a8 100644
--- a/ast.h
+++ b/ast.h
@@ -935,6 +935,7 @@ struct ast_variable_definition_t
     int					level;
 
     gboolean				field;
+    gboolean				parameter;
     gboolean				used;
 };
 
@@ -1451,6 +1452,10 @@ gboolean		   ast_encloses           (ast_t           *outer,
 						   ast_t           *inner);
 void                       ast_ensure_ast         (ast_t	   *ast);
 
+void program_breadth_first (ast_program_t *program,
+			    node_callback_t callback,
+			    gpointer data);
+
 /* Garbage Collector */
 void  gc_init  (void);
 void *gc_alloc (int n_bytes);
diff --git a/interpret.c b/interpret.c
index 2b8a07a..d5b261d 100644
--- a/interpret.c
+++ b/interpret.c
@@ -217,6 +217,8 @@ interpret (ast_t *ast)
 
     env = gc_alloc (program->env_size);
 
+    g_print ("size of env: %d\n", program->env_size);
+    
     current = program->enter;
     while (current)
     {
diff --git a/offsets.c b/offsets.c
index 32f3614..0504d7f 100644
--- a/offsets.c
+++ b/offsets.c
@@ -59,18 +59,21 @@ assign_offsets (symbol_table_t *symbols, int offset, int *max)
     {
 	ast_definition_t *definition = definitions->pdata[i];
 
-	if (definition->common.type == AST_VARIABLE_DEFINITION	&&
-	    definition->variable.used)
+	if (definition->common.type == AST_VARIABLE_DEFINITION)
 	{
-	    int size = ast_type_spec_get_size (definition->variable.type_spec);
-
-	    /* Align to size */
-	    if (offset % size != 0)
-		offset += (size - offset % size);
-
-	    definition->variable.offset = offset;
-
-	    offset += size;
+	    ast_variable_definition_t *variable = &definition->variable;
+
+	    if (variable->used || variable->parameter)
+	    {
+		int size = ast_type_spec_get_size (variable->type_spec);
+		
+		/* Align to size */
+		if (offset % size != 0)
+		    offset += (size - offset % size);
+		
+		variable->offset = offset;
+		offset += size;
+	    }
 	}
     }
 
@@ -145,8 +148,7 @@ do_offsets (ast_t *ast, int offset, int *max)
 gboolean
 offsets (ast_t *ast)
 {
-    node_breadth_first (ast->program.enter, mark_used, NULL);
-
+    program_breadth_first (&ast->program, mark_used, NULL);
     do_offsets (ast, 0, NULL);
 
     /* The offsets pass can never fail */
diff --git a/optimize.c b/optimize.c
index 508f5e6..42c2d7d 100644
--- a/optimize.c
+++ b/optimize.c
@@ -416,6 +416,30 @@ peephole (node_t *node,
 
 	*changed = TRUE;
     }
+    else if (node_is (node0, NODE_STORE)				&&
+	     node_is (node1, NODE_LOAD)					&&
+	     node0->store.definition == node1->load.definition)
+    {
+	node_t *n;
+
+	n = node_new_dup (node1, NULL);
+	node_new_store (
+	    node0->store.definition, node0->store.expression,
+	    n, node0->common.ast);
+	
+	nop_node (node0, 0);
+	nop_node (node1, 0);
+
+	*changed = TRUE;
+    }
+    else if (node_is (node0, NODE_DUP) &&
+	     node_is (node1, NODE_POP))
+    {
+	nop_node (node0, 0);
+	nop_node (node1, 0);
+
+	*changed = TRUE;
+    }
 
     node->common.next = peephole (node->common.next, changed);
 
@@ -504,7 +528,8 @@ optimize (ast_t *ast)
 	changed = FALSE;
 
 	mark_variables_unused (ast);
-	node_breadth_first (ast->program.enter, mark_used, NULL);
+
+	program_breadth_first (&ast->program, mark_used, NULL);
 	
 	do_optimize (ast, &changed);
     } while (changed);
diff --git a/prepare.c b/prepare.c
index cc8fa98..9a244c4 100644
--- a/prepare.c
+++ b/prepare.c
@@ -139,6 +139,8 @@ prepare_function (ast_function_definition_t *function,
 
 	parameter = function->parameters[i];
 
+	parameter->parameter = TRUE;
+	
 	if (!prepare_definition ((ast_definition_t *)parameter, parent, info))
 	    return FALSE;
     }
diff --git a/util.c b/util.c
index 270f2a3..38ed9b7 100644
--- a/util.c
+++ b/util.c
@@ -455,3 +455,15 @@ report_error (const char *fmt, ...)
 
     return FALSE;
 }
+
+void
+program_breadth_first (ast_program_t   *program,
+		       node_callback_t  callback,
+		       gpointer	        data)
+{
+    int i;
+
+    node_breadth_first (program->enter, callback, data);
+    for (i = 0; program->functions[i]; ++i)
+	node_breadth_first (program->functions[i]->enter, callback, data);
+}