[pypy-commit] pypy anntype: Improve exception analysis.

[rlamy]

Author: Ronan Lamy <ronan.lamy at gmail.com>
Branch: anntype
Changeset: r80763:da3a7fd425fb
Date: 2015-11-18 16:44 +0000
http://bitbucket.org/pypy/pypy/changeset/da3a7fd425fb/

Log:	Improve exception analysis.

	Reframe except clause handling in terms of annotations.

diff --git a/rpython/annotator/annrpython.py b/rpython/annotator/annrpython.py
--- a/rpython/annotator/annrpython.py
+++ b/rpython/annotator/annrpython.py
@@ -10,7 +10,8 @@
 from rpython.flowspace.model import Variable, Constant, checkgraph
 from rpython.translator import simplify, transform
 from rpython.annotator import model as annmodel, signature
-from rpython.annotator.model import SomeTypeOf
+from rpython.annotator.model import (
+        SomeTypeOf, SomeException, s_ImpossibleValue)
 from rpython.annotator.bookkeeper import Bookkeeper
 from rpython.rtyper.normalizecalls import perform_normalizations
 
@@ -210,7 +211,7 @@
         for graph in newgraphs:
             v = graph.getreturnvar()
             if v.annotation is None:
-                self.setbinding(v, annmodel.s_ImpossibleValue)
+                self.setbinding(v, s_ImpossibleValue)
 
     def validate(self):
         """Check that the annotation results are valid"""
@@ -282,7 +283,7 @@
         except KeyError:
             # the function didn't reach any return statement so far.
             # (some functions actually never do, they always raise exceptions)
-            return annmodel.s_ImpossibleValue
+            return s_ImpossibleValue
 
     def reflowfromposition(self, position_key):
         graph, block, index = position_key
@@ -493,15 +494,21 @@
                 # filter out those exceptions which cannot
                 # occur for this specific, typed operation.
                 candidates = can_only_throw
+                s_exception = SomeException(set(can_only_throw))
                 for link in exits:
                     case = link.exitcase
+                    s_case = SomeException({case})
                     if case is None:
                         self.follow_link(graph, link, {})
                         continue
-                    covered = [c for c in candidates if issubclass(c, case)]
-                    if covered:
-                        self.follow_raise_link(graph, link, {})
-                        candidates = [c for c in candidates if c not in covered]
+                    if s_exception == s_ImpossibleValue:
+                        break
+                    s_matching_exc = s_exception.intersection(s_case)
+                    if s_matching_exc != s_ImpossibleValue:
+                        self.follow_raise_link(graph, link,
+                            constraints={link.last_exc_value:
+                                s_matching_exc.as_SomeInstance(self.bookkeeper)})
+                    s_exception = s_exception.difference(s_case)
             else:
                 for link in exits:
                     if link.exitcase is None:
@@ -543,7 +550,7 @@
                 s_constraint = constraints[v_out]
                 s_out = pair(s_out, s_constraint).improve()
                 # ignore links that try to pass impossible values
-                if s_out == annmodel.s_ImpossibleValue:
+                if s_out == s_ImpossibleValue:
                     ignore_link = True
             s_out = self.apply_renaming(s_out, renaming)
             inputs_s.append(s_out)
@@ -588,7 +595,7 @@
                     s_constraint = constraints[v_out]
                     s_out = pair(s_out, s_constraint).improve()
                     # ignore links that try to pass impossible values
-                    if s_out == annmodel.s_ImpossibleValue:
+                    if s_out == s_ImpossibleValue:
                         ignore_link = True
                 s_out = self.apply_renaming(s_out, renaming)
                 inputs_s.append(s_out)
@@ -612,8 +619,8 @@
                 raise BlockedInference(self, op, -1)
         resultcell = op.consider(self)
         if resultcell is None:
-            resultcell = annmodel.s_ImpossibleValue
-        elif resultcell == annmodel.s_ImpossibleValue:
+            resultcell = s_ImpossibleValue
+        elif resultcell == s_ImpossibleValue:
             raise BlockedInference(self, op, -1) # the operation cannot succeed
         assert isinstance(resultcell, annmodel.SomeObject)
         assert isinstance(op.result, Variable)
diff --git a/rpython/annotator/model.py b/rpython/annotator/model.py
--- a/rpython/annotator/model.py
+++ b/rpython/annotator/model.py
@@ -445,6 +445,29 @@
     def noneify(self):
         return SomeInstance(self.classdef, can_be_None=True)
 
+class SomeException(SomeObject):
+    def __init__(self, classes):
+        self.classes = classes
+
+    def intersection(self, other):
+        classes = {c for c in self.classes
+            if any(issubclass(c, c2) for c2 in other.classes)}
+        if classes:
+            return SomeException(classes)
+        else:
+            return s_ImpossibleValue
+
+    def difference(self, other):
+        classes = {c for c in self.classes
+            if not any(issubclass(c, c2) for c2 in other.classes)}
+        if classes:
+            return SomeException(classes)
+        else:
+            return s_ImpossibleValue
+
+    def as_SomeInstance(self, bk):
+        return unionof(*[bk.valueoftype(cls) for cls in self.classes])
+
 
 class SomePBC(SomeObject):
     """Stands for a global user instance, built prior to the analysis,
diff --git a/rpython/annotator/test/test_annrpython.py b/rpython/annotator/test/test_annrpython.py
--- a/rpython/annotator/test/test_annrpython.py
+++ b/rpython/annotator/test/test_annrpython.py
@@ -698,6 +698,19 @@
         s = a.build_types(snippet.exc_deduction_our_excs_plus_others, [])
         assert isinstance(s, annmodel.SomeInteger)
 
+    def test_method_exception_specialization(self):
+        def f(l):
+            try:
+                return l.pop()
+            except Exception:
+                raise
+        a = self.RPythonAnnotator()
+        s = a.build_types(f, [[int]])
+        graph = graphof(a, f)
+        etype, evalue = graph.exceptblock.inputargs
+        assert evalue.annotation.classdef.shortname == 'IndexError'
+        #assert etype.const == IndexError
+
     def test_operation_always_raising(self):
         def operation_always_raising(n):
             lst = []