Speed up rebuilder considerably by computing line numbers lazily.

Fetching the last child of each of hundreds of thousands of nodes is
relatively expensive, and most of the time this information is never
used, so don't actually figure it out until it's asked for.  Saves the
overhead of quite a few function calls, too.

1 files changed, 17 insertions, 16 deletions

diff --git a/node_classes.py b/node_classes.py
index e247392e..45a00ba9 100644
--- a/node_classes.py
+++ b/node_classes.py
@@ -20,6 +20,8 @@
 
 import sys
 
+from logilab.common.decorators import cachedproperty
+
 from astroid.exceptions import NoDefault
 from astroid.bases import (NodeNG, Statement, Instance, InferenceContext,
                                  _infer_stmts, YES, BUILTINS)
@@ -267,6 +269,11 @@ class Arguments(NodeNG, AssignTypeMixin):
             return name
         return None
 
+    @cachedproperty
+    def fromlineno(self):
+        lineno = super(Arguments, self).fromlineno
+        return max(lineno, self.parent.fromlineno)
+
     def format_args(self):
         """return arguments formatted as string"""
         result = []
@@ -560,7 +567,8 @@ class ExceptHandler(Statement, AssignTypeMixin):
     name = None
     body = None
 
-    def _blockstart_toline(self):
+    @cachedproperty
+    def blockstart_tolineno(self):
         if self.name:
             return self.name.tolineno
         elif self.type:
@@ -568,11 +576,6 @@ class ExceptHandler(Statement, AssignTypeMixin):
         else:
             return self.lineno
 
-    def set_line_info(self, lastchild):
-        self.fromlineno = self.lineno
-        self.tolineno = lastchild.tolineno
-        self.blockstart_tolineno = self._blockstart_toline()
-
     def catch(self, exceptions):
         if self.type is None or exceptions is None:
             return True
@@ -603,7 +606,8 @@ class For(BlockRangeMixIn, AssignTypeMixin, Statement):
     orelse = None
 
     optional_assign = True
-    def _blockstart_toline(self):
+    @cachedproperty
+    def blockstart_tolineno(self):
         return self.iter.tolineno
 
 
@@ -638,7 +642,8 @@ class If(BlockRangeMixIn, Statement):
     body = None
     orelse = None
 
-    def _blockstart_toline(self):
+    @cachedproperty
+    def blockstart_tolineno(self):
         return self.test.tolineno
 
     def block_range(self, lineno):
@@ -789,9 +794,6 @@ class TryExcept(BlockRangeMixIn, Statement):
     def _infer_name(self, frame, name):
         return name
 
-    def _blockstart_toline(self):
-        return self.lineno
-
     def block_range(self, lineno):
         """handle block line numbers range for try/except statements"""
         last = None
@@ -811,9 +813,6 @@ class TryFinally(BlockRangeMixIn, Statement):
     body = None
     finalbody = None
 
-    def _blockstart_toline(self):
-        return self.lineno
-
     def block_range(self, lineno):
         """handle block line numbers range for try/finally statements"""
         child = self.body[0]
@@ -857,7 +856,8 @@ class While(BlockRangeMixIn, Statement):
     body = None
     orelse = None
 
-    def _blockstart_toline(self):
+    @cachedproperty
+    def blockstart_tolineno(self):
         return self.test.tolineno
 
     def block_range(self, lineno):
@@ -871,7 +871,8 @@ class With(BlockRangeMixIn, AssignTypeMixin, Statement):
     items = None
     body = None
 
-    def _blockstart_toline(self):
+    @cachedproperty
+    def blockstart_tolineno(self):
         return self.items[-1][0].tolineno
 
     def get_children(self):