C++: Fix BinaryLogicalOperators always being guards

Author: Robert Marsh

cpp/ql/src/semmle/code/cpp/controlflow/IRGuards.qll

@@ -10,12 +10,13 @@ class GuardCondition extends Expr {
     exists(IRGuardCondition ir | this = ir.getUnconvertedResultExpression())
     or
     // no binary operators in the IR
-    exists(Instruction ir |
-      this.(BinaryLogicalOperation).getAnOperand().getFullyConverted() = ir.getAST()
+    exists(GuardCondition gc |
+      this.(BinaryLogicalOperation).getAnOperand()= gc
     )
     or
     // the IR short-circuits if(!x)
     (
+      // don't produce a guard condition for `y = !x` and other non-short-circuited cases
       not exists (Instruction inst | this.getFullyConverted() = inst.getAST()) and
       exists(IRGuardCondition ir | this.(NotExpr).getOperand() = ir.getAST())
     )

cpp/ql/test/library-tests/controlflow/guards-ir/ASTGuards.expected

@@ -27,6 +27,9 @@
 | test.c:138:9:138:9 | i |
 | test.c:146:7:146:8 | ! ... |
 | test.c:146:8:146:8 | x |
+| test.c:152:10:152:10 | x |
+| test.c:152:10:152:15 | ... && ... |
+| test.c:152:15:152:15 | y |
 | test.cpp:18:8:18:10 | call to get |
 | test.cpp:31:7:31:13 | ... == ... |
 | test.cpp:42:13:42:20 | call to getABool |

cpp/ql/test/library-tests/controlflow/guards-ir/ASTGuardsControl.expected

@@ -82,6 +82,10 @@
 | test.c:138:9:138:9 | i | true | 138 | 139 |
 | test.c:146:7:146:8 | ! ... | true | 146 | 147 |
 | test.c:146:8:146:8 | x | false | 146 | 147 |
+| test.c:152:10:152:10 | x | true | 151 | 152 |
+| test.c:152:10:152:10 | x | true | 152 | 152 |
+| test.c:152:10:152:15 | ... && ... | true | 151 | 152 |
+| test.c:152:15:152:15 | y | true | 151 | 152 |
 | test.cpp:18:8:18:10 | call to get | true | 19 | 19 |
 | test.cpp:31:7:31:13 | ... == ... | false | 30 | 30 |
 | test.cpp:31:7:31:13 | ... == ... | false | 34 | 34 |

cpp/ql/test/library-tests/controlflow/guards-ir/IRGuards.expected

@@ -21,6 +21,8 @@
 | test.c:137:7:137:7 | 0 |
 | test.c:138:9:138:9 | i |
 | test.c:146:8:146:8 | x |
+| test.c:152:10:152:10 | x |
+| test.c:152:15:152:15 | y |
 | test.cpp:18:8:18:12 | (bool)... |
 | test.cpp:31:7:31:13 | ... == ... |
 | test.cpp:42:13:42:20 | call to getABool |

cpp/ql/test/library-tests/controlflow/guards-ir/IRGuardsControl.expected

@@ -78,6 +78,8 @@
 | test.c:137:7:137:7 | 0 | true | 139 | 139 |
 | test.c:138:9:138:9 | i | true | 139 | 139 |
 | test.c:146:8:146:8 | x | false | 147 | 147 |
+| test.c:152:10:152:10 | x | true | 152 | 152 |
+| test.c:152:15:152:15 | y | true | 152 | 152 |
 | test.cpp:18:8:18:12 | (bool)... | true | 0 | 0 |
 | test.cpp:31:7:31:13 | ... == ... | false | 34 | 34 |
 | test.cpp:31:7:31:13 | ... == ... | true | 30 | 30 |

cpp/ql/test/library-tests/controlflow/guards-ir/test.c

@@ -147,3 +147,8 @@ void test5(int x) {
     test3();
   }
 }
+
+void test6(int x, int y) {
+  return x && y;
+}
+