added global optimizations and fixed bugs in basic blocks.

src/basic_block.py

@@ -18,12 +18,12 @@ def find_leaders(statements):
     for i, statement in enumerate(statements[1:]):
         if is_jump(statement):
             leaders.append(i + 2)
-            print statement[2]['args'][-1]
+#            print statement[2]['args'][-1]
             jump_target_labels.append(statement[2]['args'][-1])
             #print 'found jump:', i, statement
 
-    print 'target labels:', jump_target_labels
-    print 'leaders:', leaders
+#    print 'target labels:', jump_target_labels
+#    print 'leaders:', leaders
 
     # Append jump targets
     for i, statement in enumerate(statements[1:]):
@@ -32,7 +32,9 @@ def find_leaders(statements):
                 and statement[1] in jump_target_labels:
             leaders.append(i + 1)
             #print 'target:', i + 1, statements[i + 1]
-
+    
+    leaders.sort()
+    
     return leaders
 
 def find_basic_blocks(statements):
@@ -45,5 +47,5 @@ def find_basic_blocks(statements):
         blocks.append(statements[leaders[i]:leaders[i + 1]])
 
     blocks.append(statements[leaders[-1]:])
-
+    
     return blocks

src/optimize.py

@@ -1,7 +1,7 @@
 #!/usr/bin/python
 from parser import parse_file
 from basic_block import find_basic_blocks
-from optimizer import optimize_blocks
+from optimizer import optimize_blocks, optimize_global
 from writer import write_statements
 
 if __name__ == '__main__':
@@ -13,6 +13,12 @@ if __name__ == '__main__':
 
     # Parse File
     statements = parse_file(argv[1])
+    st_original = len(statements)
+    
+    # Optimize on a global level
+    statements = optimize_global(statements)
+    
+    st_aft_global = len(statements)
 
     # Create basic blocks
     blocks = find_basic_blocks(statements)
@@ -22,6 +28,11 @@ if __name__ == '__main__':
 
     # Rewrite to assembly
     out = write_statements(statements)
+    
+    print "Optimization:"
+    print "Original statements:" + str(st_original)
+    print "After global optimization:" + str(st_aft_global)
+    print "After basic blocks optimization:" + str(len(statements))
 
     if len(argv) > 2:
         # Save output assembly

src/optimizer.py

@@ -1,3 +1,20 @@
+def equal_mov(statement):
+    '''Check for useless move operations.'''
+    stype, name, args = statement
+    return stype == 'command' and name == 'move' \
+        and args['args'][0] == args['args'][1]
+    
+def empty_shift(statement):
+    '''Check for useless shift operations.'''
+    shift_types = ['sll', 'sla', 'srl', 'sra']
+    stype, name, args = statement
+    return stype == 'command' and name in shift_types and \
+        args['args'][0] == args['args'][1] and args['args'][2] == 0
+
+def optimize_global(statements):
+    '''Optimize one-line statements in entire code.'''
+    return filter(lambda s: not equal_mov(s) and not empty_shift(s), statements)
+
 def optimize_blocks(blocks):
     '''Call the optimizer for each basic block. Do this several times until
     no more optimizations are achieved.'''