Merge pull request #1292 from markshannon/python-prune-in-ql

Python: Do pruning in QL.

python/ql/test/library-tests/ControlFlow/pruning/Constraint.expected

@@ -0,0 +1,107 @@
+| 8 | test | test | Truthy |
+| 10 | test | test | Truthy |
+| 14 | seq | seq | Truthy |
+| 16 | seq | seq | Truthy |
+| 17 | seq | seq | Truthy |
+| 21 | UnaryExpr | t1 | Falsey |
+| 21 | t1 | t1 | Truthy |
+| 24 | t1 | t1 | Truthy |
+| 25 | t1 | t1 | Truthy |
+| 26 | t2 | t2 | Truthy |
+| 29 | t2 | t2 | Truthy |
+| 30 | t2 | t2 | Truthy |
+| 31 | t3 | t3 | Truthy |
+| 31 | t4 | t4 | Truthy |
+| 32 | t3 | t3 | Truthy |
+| 33 | t3 | t3 | Truthy |
+| 34 | t3 | t3 | Truthy |
+| 35 | t4 | t4 | Truthy |
+| 36 | t5 | t5 | Truthy |
+| 36 | t6 | t6 | Truthy |
+| 37 | t5 | t5 | Truthy |
+| 38 | t5 | t5 | Truthy |
+| 39 | t6 | t6 | Truthy |
+| 40 | t6 | t6 | Truthy |
+| 43 | t1 | t1 | Truthy |
+| 44 | UnaryExpr | t2 | Falsey |
+| 44 | t2 | t2 | Truthy |
+| 47 | t1 | t1 | Truthy |
+| 48 | t2 | t2 | Truthy |
+| 49 | t2 | t2 | Truthy |
+| 51 | t2 | t2 | Truthy |
+| 52 | t2 | t2 | Truthy |
+| 55 | seq1 | seq1 | Truthy |
+| 57 | UnaryExpr | seq2 | Falsey |
+| 57 | seq2 | seq2 | Truthy |
+| 60 | seq1 | seq1 | Truthy |
+| 62 | seq1 | seq1 | Truthy |
+| 63 | seq2 | seq2 | Truthy |
+| 65 | seq2 | seq2 | Truthy |
+| 66 | seq3 | seq3 | Truthy |
+| 68 | UnaryExpr | seq4 | Falsey |
+| 68 | seq4 | seq4 | Truthy |
+| 71 | seq3 | seq3 | Truthy |
+| 73 | var | var | Truthy |
+| 74 | seq4 | seq4 | Truthy |
+| 76 | var | var | Truthy |
+| 78 | seq5 | seq5 | Truthy |
+| 80 | seq5 | seq5 | Truthy |
+| 81 | seq5 | seq5 | Truthy |
+| 83 | var | var | Truthy |
+| 88 | UnaryExpr | x | Falsey |
+| 88 | x | x | Truthy |
+| 89 | Exception | Exception | Truthy |
+| 90 | y | y | Truthy |
+| 91 | Exception | Exception | Truthy |
+| 92 | make_a_call | make_a_call | Truthy |
+| 93 | UnaryExpr | x | Falsey |
+| 93 | x | x | Truthy |
+| 94 | count | count | Truthy |
+| 95 | y | y | Truthy |
+| 96 | count | count | Truthy |
+| 101 | make_a_call | make_a_call | Truthy |
+| 102 | UnaryExpr | another_module | Falsey |
+| 102 | another_module | another_module | Truthy |
+| 103 | count | count | Truthy |
+| 107 | UnaryExpr | t1 | Falsey |
+| 107 | t1 | t1 | Truthy |
+| 109 | t2 | t2 | Truthy |
+| 111 | t1 | t1 | Truthy |
+| 113 | UnaryExpr | t2 | Falsey |
+| 113 | t2 | t2 | Truthy |
+| 117 | UnaryExpr | test | Falsey |
+| 117 | test | test | Truthy |
+| 119 | UnaryExpr | test | Falsey |
+| 119 | test | test | Truthy |
+| 123 | m | m | Truthy |
+| 125 | m | m | Truthy |
+| 126 | m | m | Truthy |
+| 158 | Compare | ps | Is not None |
+| 158 | ps | ps | Truthy |
+| 159 | ps | ps | Truthy |
+| 160 | Compare | ps | Is None |
+| 160 | ps | ps | Truthy |
+| 171 | __name__ | __name__ | Truthy |
+| 172 | None | None | Truthy |
+| 174 | func | func | Truthy |
+| 175 | Exception | Exception | Truthy |
+| 176 | count | count | Truthy |
+| 177 | Compare | escapes | Is None |
+| 177 | None | None | Truthy |
+| 177 | escapes | escapes | Truthy |
+| 178 | count | count | Truthy |
+| 180 | count | count | Truthy |
+| 188 | true12 | true12 | Truthy |
+| 195 | Compare | x | < 4 |
+| 195 | x | x | Truthy |
+| 197 | Compare | x | < 4 |
+| 197 | x | x | Truthy |
+| 201 | Compare | x | < 4 |
+| 201 | x | x | Truthy |
+| 203 | Compare | x | >= 4 |
+| 203 | UnaryExpr | x | < 4 |
+| 203 | x | x | Truthy |
+| 207 | Compare | x | < 4 |
+| 207 | x | x | Truthy |
+| 209 | Compare | x | < 4 |
+| 209 | x | x | Truthy |

python/ql/test/library-tests/ControlFlow/pruning/Constraint.ql

@@ -0,0 +1,10 @@
+
+import python
+
+import semmle.python.Pruning
+
+from Pruner::Constraint c, SsaVariable var, Pruner::UnprunedCfgNode node, int line
+where c = Pruner::constraintFromTest(var, node) and line = node.getNode().getLocation().getStartLine() and
+line > 0
+select line, node.getNode().toString(), var.getId(), c
+

python/ql/test/library-tests/ControlFlow/pruning/options

@@ -0,0 +1,2 @@
+semmle-extractor-options: --dont-prune-graph
+optimize: true

python/ql/test/library-tests/ControlFlow/pruning/test.expected

@@ -43,3 +43,13 @@
 | 154 | 1 |
 | 161 | 1 |
 | 163 | 1 |
+| 176 | 1 |
+| 178 | 1 |
+| 180 | 1 |
+| 184 | 1 |
+| 186 | 1 |
+| 189 | 1 |
+| 192 | 1 |
+| 198 | 0 |
+| 204 | 0 |
+| 210 | 0 |

python/ql/test/library-tests/ControlFlow/pruning/test.py

@@ -3,20 +3,20 @@
 def dead():
     return 0
     count
-    
+
 def conditional_dead(test):
     if test:
         return
     if test:
         count
-        
+
 def made_true(seq):
     if seq:
         return
     seq.append(1)
     if seq:
         count
-        
+
 def boolop(t1, t2, t3, t4, t5, t6):
     if not t1:
         return
@@ -38,7 +38,7 @@ def boolop(t1, t2, t3, t4, t5, t6):
         t5 and count
         t6 or count
         t6 and count
-        
+
 def with_splitting(t1, t2):
     if t1:
         if not t2:
@@ -50,7 +50,7 @@ def with_splitting(t1, t2):
     else:
         t2 or count
         t2 and count
-        
+
 def loops(seq1, seq2, seq3, seq4, seq5):
     if seq1:
         return
@@ -82,7 +82,7 @@ def loops(seq1, seq2, seq3, seq4, seq5):
         count
         print(var)
 
-#Logic does not apply to global variables in calls, 
+#Logic does not apply to global variables in calls,
 #as they may be changed from true to false externally.
 from some_module import x, y
 if not x:
@@ -102,7 +102,7 @@ make_a_call()
 if not another_module:
     count
 
-    
+
 def negated_conditional_live(t1, t2):
     if not t1:
         return
@@ -112,13 +112,13 @@ def negated_conditional_live(t1, t2):
         count
     if not t2:
         count
-    
+
 def negated_conditional_dead(test):
     if not test:
         return
     if not test:
         count
-        
+
 def made_true2(m):
     if m:
         return
@@ -162,3 +162,50 @@ def attribute_lookup_cannot_effect_comparisons_with_immutable_constants(ps):
     else:
         count
 
+def func():
+    global escapes
+    so_something()
+    escapes = True
+
+#Don't prune on `escapes` as it escapes.
+if __name__ == '__main__':
+    escapes = None # global
+    try:
+        func()
+    except Exception as err:
+        count
+        if escapes is None:
+            count
+        else:
+            count
+
+def func2():
+    while 1:
+        count
+        if cond12:
+            count
+            try:
+                true12()
+                count
+            except IOError:
+                true12 = 0
+                count
+
+def inequality1(x):
+    if x < 4:
+        return
+    if x < 4:
+        count
+
+def inequality2(x):
+    if x < 4:
+        return
+    if not x >= 4:
+        count
+
+def reversed_inequality(x):
+    if x < 4:
+        return
+    if 4 > x:
+        count
+