Refs #14859: Fix sizeof calculation for std::array

Author: web-flow

lib/symboldatabase.cpp

@@ -8478,7 +8478,7 @@ namespace {
 }
 
 template<class F>
-static Result accumulateStructMembers(const Scope* scope, F f, ValueType::Accuracy accuracy)
+static Result accumulateStructMembers(const Scope* scope, F f, ValueType::Accuracy accuracy, const Settings& settings)
 {
     size_t total = 0;
     std::set<const Scope*> anonScopes;
@@ -8497,6 +8497,10 @@ static Result accumulateStructMembers(const Scope* scope, F f, ValueType::Accura
                 if (ret.second)
                     total = f(total, *vt, dim, bits);
             }
+            else if (vt->container && vt->container->startPattern == "std :: array <") {
+                const ValueType vtElement = ValueType::parseDecl(vt->containerTypeToken, settings);
+                total = f(total, vtElement, dim, bits);
+            }
             else
                 total = f(total, *vt, dim, bits);
         }
@@ -8536,12 +8540,12 @@ static size_t getAlignOf(const ValueType& vt, const Settings& settings, ValueTyp
             size_t a = getAlignOf(vt2, settings, accuracy, ValueType::SizeOf::Pointer, ++maxRecursion);
             return std::max(max, a);
         };
-        Result result = accumulateStructMembers(vt.typeScope, accHelper, accuracy);
+        Result result = accumulateStructMembers(vt.typeScope, accHelper, accuracy, settings);
         size_t total = result.total;
         if (const Type* dt = vt.typeScope->definedType) {
             total = std::accumulate(dt->derivedFrom.begin(), dt->derivedFrom.end(), total, [&](size_t v, const Type::BaseInfo& bi) {
                 if (bi.type && bi.type->classScope)
-                    v += accumulateStructMembers(bi.type->classScope, accHelper, accuracy).total;
+                    v += accumulateStructMembers(bi.type->classScope, accHelper, accuracy, settings).total;
                 return v;
             });
         }
@@ -8629,14 +8633,14 @@ size_t ValueType::getSizeOf( const Settings& settings, Accuracy accuracy, SizeOf
             }
             return typeScope->type == ScopeType::eUnion ? std::max(total, n) : total + padding + n;
         };
-        Result result = accumulateStructMembers(typeScope, accHelper, accuracy);
+        Result result = accumulateStructMembers(typeScope, accHelper, accuracy, settings);
         size_t total = result.total;
         if (currentBitCount > 0)
             total += currentBitfieldAlloc;
         if (const ::Type* dt = typeScope->definedType) {
             total = std::accumulate(dt->derivedFrom.begin(), dt->derivedFrom.end(), total, [&](size_t v, const ::Type::BaseInfo& bi) {
                 if (bi.type && bi.type->classScope)
-                    v += accumulateStructMembers(bi.type->classScope, accHelper, accuracy).total;
+                    v += accumulateStructMembers(bi.type->classScope, accHelper, accuracy, settings).total;
                 return v;
             });
         }

lib/vf_common.cpp

@@ -165,7 +165,8 @@ namespace ValueFlow
             if (obj && !obj->isLiteral() && obj->valueType() &&
                 (obj->valueType()->pointer == 0 || // <- TODO this is a bailout, abort when there are array->pointer conversions
                  (obj->variable() && !obj->variable()->isArray())) &&
-                !obj->valueType()->isEnum()) { // <- TODO this is a bailout, handle enum with non-int types
+                !obj->valueType()->isEnum() &&
+                !(obj->valueType()->container && obj->valueType()->container->startPattern == "std :: array <")) { // <- TODO this is a bailout, handle enum with non-int types
                 const auto ptrPointee = obj->valueType()->pointer > 0 ? ValueType::SizeOf::Pointer : ValueType::SizeOf::Pointee;
                 const size_t sz = obj->valueType()->getSizeOf(settings, ValueType::Accuracy::ExactOrZero, ptrPointee);
                 if (sz) {
@@ -246,7 +247,12 @@ namespace ValueFlow
                         if (var->type()->classScope && var->type()->classScope->enumType)
                             size = getSizeOfType(var->type()->classScope->enumType, settings);
                     } else if (var->valueType()) {
-                        size = var->valueType()->getSizeOf(settings, ValueType::Accuracy::ExactOrZero, ValueType::SizeOf::Pointer);
+                        if (var->valueType()->container && var->valueType()->container->startPattern == "std :: array <") {
+                            const ValueType vtElement = ValueType::parseDecl(var->valueType()->containerTypeToken, settings);
+                            size = vtElement.getSizeOf(settings, ValueType::Accuracy::ExactOrZero, ValueType::SizeOf::Pointer);
+                        }
+                        else
+                            size = var->valueType()->getSizeOf(settings, ValueType::Accuracy::ExactOrZero, ValueType::SizeOf::Pointer);
                     } else if (!var->type()) {
                         size = getSizeOfType(var->typeStartToken(), settings);
                     }

test/testvalueflow.cpp

@@ -1812,6 +1812,20 @@ class TestValueFlow : public TestFixture {
         ASSERT_EQUALS(1U, values.size());
         ASSERT_EQUALS(2 * settings.platform.sizeof_pointer, values.back().intvalue);
         ASSERT_EQUALS_ENUM(ValueFlow::Value::ValueKind::Known, values.back().valueKind);
+
+        code = "struct S { std::array<int, 3> a; };\n"
+               "x = sizeof(S);\n";
+        values = tokenValues(code, "( S");
+        ASSERT_EQUALS(1U, values.size());
+        ASSERT_EQUALS(3 * settings.platform.sizeof_int, values.back().intvalue);
+        ASSERT_EQUALS_ENUM(ValueFlow::Value::ValueKind::Known, values.back().valueKind);
+
+        code = "std::array<int, 3> a;\n"
+               "x = sizeof(a);\n";
+        values = tokenValues(code, "( a");
+        ASSERT_EQUALS(1U, values.size());
+        ASSERT_EQUALS(3 * settings.platform.sizeof_int, values.back().intvalue);
+        ASSERT_EQUALS_ENUM(ValueFlow::Value::ValueKind::Known, values.back().valueKind);
     }
 
     void valueFlowComma()