Support for break/continue

2 files changed, 47 insertions, 4 deletions

diff --git a/README b/README
index f695e1a..fe2a379 100644
--- a/README
+++ b/README
@@ -85,9 +85,9 @@ A9.3 Compound statement - supported
 A9.4 Selection statements - if and if/else are supported, switch is not
 A9.5 Iteration statements - while, do/while and for are supported. A missing
             second expression in the for is equivalent to a non-zero constant
-A9.6 Jump statements - goto is unsupported. continue, break are not supported
-            yet. return is supported with and without value. The function
-            result is undefined for the second case
+A9.6 Jump statements - goto is unsupported. continue, break are supported.
+            return is supported with and without value. The function result is
+            undefined for the second case
 
 A10 External Declarations
 A10.1 Function Definitions - unsupported: extern static, parameters. Old style
diff --git a/pp2cc.py b/pp2cc.py
index bc782c3..57c53f3 100755
--- a/pp2cc.py
+++ b/pp2cc.py
@@ -159,6 +159,8 @@ class LinkedNode(object):
         self.node = node
         self.parent = parent
         self.function = None
+        self.break_label = None
+        self.continue_label = None
         self.level = 0
         # inherit level from parent
         if parent:
@@ -181,6 +183,23 @@ class LinkedNode(object):
         if hasattr(self.node, "coord"):
             return self.node.coord
         return "Unknown"
+    def setLoop(self, break_label, continue_label):
+        """Marks this node as a loop with the labels to continue after a jump
+        
+        Keywords list:
+        break_label -- The label to continue when using the break keyword
+        continue_label -- The label to continue when using the continue keyword
+        """
+        self.break_label = break_label
+        self.continue_label = continue_label
+    def getLoopNode(self):
+        # continue_label is implied with break_label
+        if self.break_label is not None:
+            return self
+        if self.parent:
+            assert isinstance(self.parent, LinkedNode), "parent is not a LinkedNode!"
+            return self.parent.getLoopNode()
+        return None
 
 class Function(object):
     def __init__(self, node):
@@ -739,18 +758,29 @@ class Parse(object):
     def parseDoWhile(self, linked_node):
         node = linked_node.node
         lbl_do = self.uniqLbl("do")
+        # used for supporting continue/break
+        lbl_cond = self.uniqLbl("doCond")
+        lbl_end = self.uniqLbl("doEnd")
+        linked_node.setLoop(lbl_end, lbl_doCond)
+
         # provides a way to redo the loop
         lines = [self.asm.noop(lbl_do)]
         # do { ... }, expect do{/*empty*/} as well
         lines += self.parseStatement(node.stmt, linked_node)
         # while (...)
+        # used for supporting continue
+        lines.append(self.asm.noop(lbl_cond))
         lines += self.parseStatement(node.cond, linked_node)
         lines.append(self.asm.branch_op("BNE", lbl_do))
+        # used for supporting break
+        lines.append(self.asm.noop(lbl_end))
         return lines
     def parseWhile(self, linked_node):
         node = linked_node.node
         lbl_while = self.uniqLbl("while")
         lbl_while_end = self.uniqLbl("whileEnd")
+        # used for supporting break/continue
+        linked_node.setLoop(lbl_while_end, lbl_while)
         # while (
         lines = [self.asm.noop(lbl_while)]
         # ..
@@ -774,6 +804,8 @@ class Parse(object):
         lines = []
         lbl_for = self.uniqLbl("for")
         lbl_for_end = self.uniqLbl("forEnd")
+        # used for supporting break/continue
+        linked_node.setLoop(lbl_for_end, lbl_for)
 
         if node.init: # init;
             lines += self.parseStatement(node.init, linked_node)
@@ -838,6 +870,16 @@ class Parse(object):
             else:
                 lines += init_val
         return lines
+    def parseBreak(self, linked_node):
+        loop_node = linked_node.getLoopNode()
+        if not loop_node:
+            raise RuntimeError("break not in a loop")
+        return [self.asm.branch_op("BRA", loop_node.break_label)]
+    def parseContinue(self, linked_node):
+        loop_node = linked_node.getLoopNode()
+        if not loop_node:
+            raise RuntimeError("continue not in a loop")
+        return [self.asm.branch_op("BRA", loop_node.continue_label)]
     def parseStatement(self, node, parent_linked_node, level_increment=False):
         linked_node = LinkedNode(node, parent_linked_node, level_increment=level_increment)
         self.asm.level = linked_node.level
@@ -850,7 +892,8 @@ class Parse(object):
             for entry in ("Compound", "BinaryOp", "If", "Constant", "ID",
                           "Return", "FuncCall", "UnaryOp", "Cast",
                           "TernaryOp", "DoWhile", "While", "For", "ExprList",
-                          "Assignment", "Decl", "FuncDef"):
+                          "Assignment", "Decl", "FuncDef", "Break",
+                          "Continue"):
                 if isinstance(node, getattr(c_ast, entry)):
                     lines += getattr(self, "parse" + entry)(linked_node)
                     break