Address incorrect is compiled evaluated logic

Need to consider all possible values passed as arguments and
default values.

Author: rvermeulen

cpp/autosar/src/rules/A7-1-2/VariableMissingConstexpr.ql

@@ -33,12 +33,24 @@ predicate isTypeZeroInitializable(Type t) {
   t.getUnderlyingType() instanceof ArrayType
 }
 
+/*
+  * Returns true if the given call may be evaluated at compile time and is compile time evaluated because
+  * all its arguments are compile time evaluated and its default values are compile time evaluated.
+  */
 predicate isCompileTimeEvaluated(Call call) {
+  // 1. The call may be evaluated at compile time, because it is constexpr, and
   call.getTarget().isConstexpr() and
-  forall(Expr arg | arg = call.getAnArgument() |
-    DataFlow::localExprFlow(any(Literal l), arg)
+  // 2. all its arguments are compile time evaluated, and
+  forall(DataFlow::Node ultimateArgSource | DataFlow::localFlow(ultimateArgSource, DataFlow::exprNode(call.getAnArgument())) and not DataFlow::localFlowStep(_, ultimateArgSource) |
+    ultimateArgSource.asExpr() instanceof Literal
     or
-    DataFlow::localExprFlow(any(Call c | isCompileTimeEvaluated(call)), arg)
+    any(Call c | isCompileTimeEvaluated(c)) = ultimateArgSource.asExpr()
+  ) and
+  // 3. all the default values used are compile time evaluated.
+  forall(Expr defaultValue, Parameter parameterUsingDefaultValue, int idx | parameterUsingDefaultValue = call.getTarget().getParameter(idx) and not exists(call.getArgument(idx)) and parameterUsingDefaultValue.getAnAssignedValue() = defaultValue |
+    defaultValue instanceof Literal
+    or
+    any(Call c | isCompileTimeEvaluated(c)) = defaultValue
   )
 }
 

cpp/autosar/test/rules/A7-1-2/VariableMissingConstexpr.expected

@@ -10,4 +10,15 @@
 | test.cpp:55:7:55:8 | m2 | Variable m2 could be marked 'constexpr'. |
 | test.cpp:130:7:130:8 | m1 | Variable m1 could be marked 'constexpr'. |
 | test.cpp:141:7:141:8 | m1 | Variable m1 could be marked 'constexpr'. |
-| test.cpp:212:7:212:7 | x | Variable x could be marked 'constexpr'. |
+| test.cpp:217:7:217:7 | x | Variable x could be marked 'constexpr'. |
+| test.cpp:228:7:228:7 | v | Variable v could be marked 'constexpr'. |
+| test.cpp:229:7:229:7 | w | Variable w could be marked 'constexpr'. |
+| test.cpp:230:7:230:7 | a | Variable a could be marked 'constexpr'. |
+| test.cpp:231:7:231:7 | b | Variable b could be marked 'constexpr'. |
+| test.cpp:235:7:235:7 | f | Variable f could be marked 'constexpr'. |
+| test.cpp:236:7:236:7 | g | Variable g could be marked 'constexpr'. |
+| test.cpp:237:7:237:7 | h | Variable h could be marked 'constexpr'. |
+| test.cpp:238:7:238:7 | i | Variable i could be marked 'constexpr'. |
+| test.cpp:241:7:241:7 | l | Variable l could be marked 'constexpr'. |
+| test.cpp:244:7:244:7 | o | Variable o could be marked 'constexpr'. |
+| test.cpp:245:7:245:7 | q | Variable q could be marked 'constexpr'. |

cpp/autosar/test/rules/A7-1-2/test.cpp

@@ -206,9 +206,42 @@ class ExcludedCases {
   void operator=(ExcludedCases &&) {} // COMPLIANT
 };
 
+extern int random();
 constexpr int add(int x, int y) { return x + y; }
+constexpr int add1(int x, int y = 1) { return x + y; }
+constexpr int add2(int x, int y = add(add1(1), 2)) { return x + y; }
+constexpr int add3(int x, int y = random()) { return x + y; }
+constexpr int add4(int x = 1, int y = 2) { return x + y; }
 
 constexpr void fp_reported_in_466(int p) {
   int x = add(1, 2); // NON_COMPLIANT
   int y = add(1, p); // COMPLIANT
+
+  int z = 0;
+  if (p > 0) {
+    z = 1;
+  } else {
+    z = p;
+  }
+
+  int u = add(z, 2);  // COMPLIANT
+  int v = add(x, 2);  // NON_COMPLIANT
+  int w = add1(x, 2); // NON_COMPLIANT
+  int a = add1(x);    // NON_COMPLIANT
+  int b = add1(1);    // NON_COMPLIANT
+  int c = add1(1, z); // COMPLIANT
+  int d = add1(1, z); // COMPLIANT
+  int e = add1(z);    // COMPLIANT
+  int f = add2(1);    // NON_COMPLIANT
+  int g = add2(1, 2); // NON_COMPLIANT
+  int h = add2(x, 2); // NON_COMPLIANT
+  int i = add2(x, 2); // NON_COMPLIANT
+  int j = add2(z);    // COMPLIANT
+  int k = add2(z, 1); // COMPLIANT
+  int l = add3(1, 1); // NON_COMPLIANT
+  int m = add3(1);    // COMPLIANT
+  int n = add3(1, z); // COMPLIANT
+  int o = add4();     // NON_COMPLIANT
+  int q = add4(1);    // NON_COMPLIANT
+  int r = add4(1, z); // COMPLIANT
 }