[CPP-434] Address comments regarding .ql and .qhelp.

zlaski-semmle · zlaski-semmle · commit f964fe8b0ee9 · 2019-10-25T14:08:30.000-07:00
diff --git a/cpp/ql/src/Likely Bugs/Arithmetic/SignedOverflowCheck.qhelp b/cpp/ql/src/Likely Bugs/Arithmetic/SignedOverflowCheck.qhelp
@@ -4,16 +4,16 @@
 <qhelp>
 <overview>
 <p>
-Testing for <code>signed</code> integer overflow by adding a
-value to a variable and then comparing the result to that variable
-is not defined by the C or C++ standards.  The comparison may
-produce an unintended result, or may be deleted by the compiler
-entirely.
+Testing for signed integer overflow by adding a
+two signed values together and then comparing the result to one
+of the values is ill-formed since the overflow check is undefined.
+The comparison may produce an unintended result, or may be deleted
+by the compiler entirely.
 </p>
 </overview>
 <recommendation>
 <p>
-Make sure that the comparison in question uses <i>unsigned</i> values.
+When checking for overflow, make sure that <code>unsigned</code> values are used.
 </p>
 </recommendation>
 <example>
diff --git a/cpp/ql/src/Likely Bugs/Arithmetic/SignedOverflowCheck.ql b/cpp/ql/src/Likely Bugs/Arithmetic/SignedOverflowCheck.ql
@@ -2,7 +2,7 @@
  * @name Undefined result of signed test for overflow
  * @description Testing for overflow by adding a value to a variable
  *              to see if it "wraps around" works only for
- *              `unsigned` integer values.
+ *              unsigned integer values.
  * @kind problem
  * @problem.severity warning
  * @precision high
@@ -15,12 +15,12 @@ import cpp
 private import semmle.code.cpp.valuenumbering.GlobalValueNumbering
 private import semmle.code.cpp.rangeanalysis.SimpleRangeAnalysis
 
-from RelationalOperation ro, AddExpr add, VariableAccess va1, VariableAccess va2
+from RelationalOperation ro, AddExpr add, Expr expr1, Expr expr2
 where
   ro.getAnOperand() = add and
-  add.getAnOperand() = va1 and
-  ro.getAnOperand() = va2 and
-  globalValueNumber(va1) = globalValueNumber(va2) and
-  add.getType().getUnspecifiedType().(IntegralType).isSigned() and
+  add.getAnOperand() = expr1 and
+  ro.getAnOperand() = expr2 and
+  globalValueNumber(expr1) = globalValueNumber(expr2) and
+  add.getUnspecifiedType().(IntegralType).isSigned() and
   exprMightOverflowPositively(add)
 select ro, "Testing for signed overflow may produce undefined results."
