Much simpler graph based return check

1 files changed, 21 insertions, 106 deletions

diff --git a/return-check.c b/return-check.c
index 197baf7..58aa86a 100644
--- a/return-check.c
+++ b/return-check.c
@@ -18,114 +18,17 @@
 
 #include "ast.h"
 
-static gboolean return_check_statement (ast_statement_t *statement,
-					gboolean	*returns);
-
 static gboolean
-return_check_function (ast_function_definition_t *function)
+check_graph (node_t *exit)
 {
-    gboolean returns;
-
-    if (!return_check_statement (function->body, &returns))
-	return FALSE;
+    int i;
 
-    if (!returns && function->return_type->common.type != AST_VOID_TYPE)
+    for (i = 0; i < exit->predecessors->len; ++i)
     {
-	g_print ("Control reaches end of non void function %s\n", function->name);
-	return FALSE;
-    }
-    
-    return TRUE;
-}
+	node_t *pred = exit->predecessors->pdata[i];
 
-static gboolean
-return_check_definition (ast_definition_t *definition)
-{
-    switch (definition->common.type)
-    {
-    case AST_FUNCTION_DEFINITION:
-	if (!return_check_function (&definition->function))
+	if (pred->reachable && !pred->return_)
 	    return FALSE;
-	break;
-
-    case AST_VARIABLE_DEFINITION:
-	break;
-    }
-    
-    return TRUE;
-}
-
-static gboolean
-return_check_statement (ast_statement_t *statement,
-			gboolean	*returns)
-{
-    gboolean b1, b2;
-    
-    *returns = FALSE;
-    
-    switch (statement->common.type)
-    {
-    case AST_DEFINITION_STATEMENT:
-	if (!return_check_definition (statement->definition.def))
-	    return FALSE;
-	break;
-	
-    case AST_WHILE_STATEMENT:
-	if (!return_check_statement (statement->while_.body, &b1))
-	    return FALSE;
-	break;
-
-    case AST_FOR_STATEMENT:
-	if (!return_check_statement (statement->for_.body, &b1))
-	    return FALSE;
-	break;
-	
-    case AST_IF_STATEMENT:
-	if (!return_check_statement (statement->if_.then_part, &b1))
-	    return FALSE;
-
-	if (!return_check_statement (statement->if_.else_part, &b2))
-	    return FALSE;
-
-	*returns = b1 && b2;
-	break;
-	
-    case AST_COMPOUND_STATEMENT:
-	if (!return_check_statement (statement->compound.first, &b1))
-	    return FALSE;
-
-	if (!return_check_statement (statement->compound.second, &b2))
-	    return FALSE;
-
-	*returns = b1 || b2;
-	break;
-	
-    case AST_BLOCK_STATEMENT:
-	if (!return_check_statement (statement->block.body, returns))
-	    return FALSE;
-	break;
-
-    case AST_GOTO_STATEMENT:
-	/* FIXME: gotos have completely broken this pass
-	 * We should probably make it graph based.
-	 */
-	break;
-
-    case AST_LABEL_STATEMENT:
-	break;
-	
-    case AST_PRINT_STATEMENT:
-	break;
-	
-    case AST_EXPRESSION_STATEMENT:
-	break;
-
-    case AST_RETURN_STATEMENT:
-	*returns = TRUE;
-	break;
-	
-    case AST_EMPTY_STATEMENT:
-	break;
     }
 
     return TRUE;
@@ -134,10 +37,22 @@ return_check_statement (ast_statement_t *statement,
 gboolean
 return_check (ast_program_t *program)
 {
-    gboolean dummy;
-    
-    if (!return_check_statement (program->statement, &dummy))
-	return FALSE;
+    int i;
+
+    for (i = 0; program->functions[i] != NULL; ++i)
+    {
+	ast_function_definition_t *function = program->functions[i];
+
+	if (function->return_type->common.type != AST_VOID_TYPE)
+	{
+	    if (function->exit && !check_graph (function->exit))
+	    {
+		g_print ("Control reaches end of non-void function %s\n",
+			 function->name);
+		return FALSE;
+	    }
+	}
+    }
 
     return TRUE;
 }