[pypy-commit] pypy default: Test and comment for elidable functions that can raise.

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r46042:37f74b79d119
Date: 2011-07-28 10:05 +0200
http://bitbucket.org/pypy/pypy/changeset/37f74b79d119/

Log:	Test and comment for elidable functions that can raise.

diff --git a/pypy/jit/metainterp/test/test_ajit.py b/pypy/jit/metainterp/test/test_ajit.py
--- a/pypy/jit/metainterp/test/test_ajit.py
+++ b/pypy/jit/metainterp/test/test_ajit.py
@@ -407,6 +407,32 @@
         # the CALL_PURE is constant-folded away by optimizeopt.py
         self.check_loops(int_sub=1, call=0, call_pure=0, getfield_gc=0)
 
+    def test_elidable_raising(self):
+        myjitdriver = JitDriver(greens = ['m'], reds = ['n'])
+        @elidable
+        def externfn(x):
+            if x <= 0:
+                raise ValueError
+            return x - 1
+        def f(n, m):
+            while n > 0:
+                myjitdriver.can_enter_jit(n=n, m=m)
+                myjitdriver.jit_merge_point(n=n, m=m)
+                try:
+                    n -= externfn(m)
+                except ValueError:
+                    n -= 1
+            return n
+        res = self.meta_interp(f, [22, 6])
+        assert res == -3
+        # the CALL_PURE is constant-folded away by optimizeopt.py
+        self.check_loops(int_sub=1, call=0, call_pure=0)
+        #
+        res = self.meta_interp(f, [22, -5])
+        assert res == 0
+        # raises: becomes CALL and is not constant-folded away
+        self.check_loops(int_sub=1, call=1, call_pure=0)
+
     def test_constant_across_mp(self):
         myjitdriver = JitDriver(greens = [], reds = ['n'])
         class X(object):
diff --git a/pypy/rlib/jit.py b/pypy/rlib/jit.py
--- a/pypy/rlib/jit.py
+++ b/pypy/rlib/jit.py
@@ -16,7 +16,8 @@
 
     Most importantly it doesn't mean that an elidable function has no observable
     side effect, but those side effects are idempotent (ie caching).
-    For now, such a function should never raise an exception.
+    The function can raise an exception, in which case this decorator is
+    ignored.
     """
     func._elidable_function_ = True
     return func