[pypy-commit] pypy less-stringly-ops: Do not create so many useless implicit exception blocks

[rlamy]

Author: Ronan Lamy <ronan.lamy at gmail.com>
Branch: less-stringly-ops
Changeset: r66246:67521a7fb22d
Date: 2013-08-12 16:23 +0100
http://bitbucket.org/pypy/pypy/changeset/67521a7fb22d/

Log:	Do not create so many useless implicit exception blocks

diff --git a/rpython/flowspace/flowcontext.py b/rpython/flowspace/flowcontext.py
--- a/rpython/flowspace/flowcontext.py
+++ b/rpython/flowspace/flowcontext.py
@@ -456,7 +456,7 @@
             self.guessexception(op.canraise)
         return op.result
 
-    def guessexception(self, exceptions):
+    def guessexception(self, exceptions, force=False):
         """
         Catch possible exceptions implicitly.
 
@@ -465,6 +465,11 @@
         even if the interpreter re-raises the exception, it will not be the
         same ImplicitOperationError instance internally.
         """
+        if not force and not any(isinstance(block, (ExceptBlock, FinallyBlock))
+                for block in self.blockstack):
+            # The implicit exception wouldn't be caught and would later get
+            # removed, so don't bother creating it.
+            return
         self.recorder.guessexception(self, *exceptions)
 
     def build_flow(self):
diff --git a/rpython/flowspace/objspace.py b/rpython/flowspace/objspace.py
--- a/rpython/flowspace/objspace.py
+++ b/rpython/flowspace/objspace.py
@@ -228,7 +228,7 @@
                     frame.replace_in_stack(it, next_unroller)
                     return const(v)
         w_item = frame.do_operation("next", w_iter)
-        frame.guessexception([StopIteration, RuntimeError])
+        frame.guessexception([StopIteration, RuntimeError], force=True)
         return w_item