Implement package SideEffects6 with rule 28.3.1, predicate should not have side effects

cpp/common/src/codingstandards/cpp/ast/Templates.qll

@@ -0,0 +1,16 @@
+import cpp
+
+/**
+ * A predicate to simplify getting a namespace for a template parameter, since
+ * `TemplateParameterType`'s `getNamespace()` has no result, and `enclosingElement()` has no result,
+ * and there are multiple cases to navigate to work around this.
+ */
+Namespace getTemplateParameterNamespace(TypeTemplateParameter param) {
+  exists(Declaration decl |
+    param = decl.(TemplateClass).getATemplateArgument() or
+    param = decl.(TemplateVariable).getATemplateArgument() or
+    param = decl.(TemplateFunction).getATemplateArgument()
+  |
+    result = decl.getNamespace()
+  )
+}

cpp/common/src/codingstandards/cpp/exclusions/cpp/RuleMetadata.qll

@@ -61,6 +61,7 @@ import Representation
 import Scope
 import SideEffects1
 import SideEffects2
+import SideEffects6
 import SmartPointers1
 import SmartPointers2
 import Statements
@@ -134,6 +135,7 @@ newtype TCPPQuery =
   TScopePackageQuery(ScopeQuery q) or
   TSideEffects1PackageQuery(SideEffects1Query q) or
   TSideEffects2PackageQuery(SideEffects2Query q) or
+  TSideEffects6PackageQuery(SideEffects6Query q) or
   TSmartPointers1PackageQuery(SmartPointers1Query q) or
   TSmartPointers2PackageQuery(SmartPointers2Query q) or
   TStatementsPackageQuery(StatementsQuery q) or
@@ -207,6 +209,7 @@ predicate isQueryMetadata(Query query, string queryId, string ruleId, string cat
   isScopeQueryMetadata(query, queryId, ruleId, category) or
   isSideEffects1QueryMetadata(query, queryId, ruleId, category) or
   isSideEffects2QueryMetadata(query, queryId, ruleId, category) or
+  isSideEffects6QueryMetadata(query, queryId, ruleId, category) or
   isSmartPointers1QueryMetadata(query, queryId, ruleId, category) or
   isSmartPointers2QueryMetadata(query, queryId, ruleId, category) or
   isStatementsQueryMetadata(query, queryId, ruleId, category) or

cpp/common/src/codingstandards/cpp/exclusions/cpp/SideEffects6.qll

@@ -0,0 +1,44 @@
+//** THIS FILE IS AUTOGENERATED, DO NOT MODIFY DIRECTLY.  **/
+import cpp
+import RuleMetadata
+import codingstandards.cpp.exclusions.RuleMetadata
+
+newtype SideEffects6Query =
+  TPredicateWithPersistentSideEffectsQuery() or
+  TNonConstPredicateFunctionObjectQuery()
+
+predicate isSideEffects6QueryMetadata(Query query, string queryId, string ruleId, string category) {
+  query =
+    // `Query` instance for the `predicateWithPersistentSideEffects` query
+    SideEffects6Package::predicateWithPersistentSideEffectsQuery() and
+  queryId =
+    // `@id` for the `predicateWithPersistentSideEffects` query
+    "cpp/misra/predicate-with-persistent-side-effects" and
+  ruleId = "RULE-28-3-1" and
+  category = "required"
+  or
+  query =
+    // `Query` instance for the `nonConstPredicateFunctionObject` query
+    SideEffects6Package::nonConstPredicateFunctionObjectQuery() and
+  queryId =
+    // `@id` for the `nonConstPredicateFunctionObject` query
+    "cpp/misra/non-const-predicate-function-object" and
+  ruleId = "RULE-28-3-1" and
+  category = "required"
+}
+
+module SideEffects6Package {
+  Query predicateWithPersistentSideEffectsQuery() {
+    //autogenerate `Query` type
+    result =
+      // `Query` type for `predicateWithPersistentSideEffects` query
+      TQueryCPP(TSideEffects6PackageQuery(TPredicateWithPersistentSideEffectsQuery()))
+  }
+
+  Query nonConstPredicateFunctionObjectQuery() {
+    //autogenerate `Query` type
+    result =
+      // `Query` type for `nonConstPredicateFunctionObject` query
+      TQueryCPP(TSideEffects6PackageQuery(TNonConstPredicateFunctionObjectQuery()))
+  }
+}

cpp/common/src/codingstandards/cpp/types/Predicate.qll

@@ -0,0 +1,118 @@
+/**
+ * A library for handling "predicate" types, which are function parameters in the standard library.
+ *
+ * For example, `std::sort` takes a predicate as its third argument, and `std::set` takes a
+ * predicate as its second template parameter. Predicates are always template parameters, and we
+ * can identify them by their name -- this is what MISRA expects us to do.
+ */
+
+import cpp
+private import codingstandards.cpp.StdNamespace
+private import codingstandards.cpp.ast.Templates
+private import codingstandards.cpp.types.Templates
+private import semmle.code.cpp.dataflow.new.DataFlow
+
+/**
+ * A "predicate" type parameter as defined by MISRA, which is a standard library function named
+ * "Compare" or "Predicate" or "BinaryPredicate" in the standard library.
+ *
+ * To be more widely useful, we match more flexibly on the name, as `_Compare` is also common, etc.
+ *
+ * To get a particular `Type` that is _used_ as a predicate type, see `getASubstitutedType()`,
+ * rather than the type parameter itself, see `getASubstitutedType()`.
+ */
+class PredicateType extends TypeTemplateParameter {
+  PredicateType() {
+    this.getName().matches(["%Compare%", "%Predicate%"]) and
+    getTemplateParameterNamespace(this) instanceof StdNS
+  }
+
+  /**
+   * Get a type that is used (anywhere, via some substitution) as this predicate type parameter.
+   *
+   * For example, `std::sort(..., ..., [](int a, int b) { return a < b; })` creates a `Closure`
+   * type, and substitutes that closure type for the predicate type parameter of `std::sort`.
+   */
+  Type getASubstitutedType(Substitution sub) { result = sub.getSubstitutedTypeForParameter(this) }
+}
+
+/**
+ * A class type that has been substituted for a predicate type parameter, and has an `operator()`
+ * member function.
+ *
+ * For example, the closure type in `std::sort(..., ..., [](int a, int b) { return a < b; })` is a
+ * `PredicateFunctionObject`, and so is any `std::less<int>` that is used as a predicate type
+ * parameter, etc.
+ *
+ * This does not cover function pointer types, as these are not class types.
+ */
+class PredicateFunctionObject extends Class {
+  PredicateType pred;
+  Function operator;
+  Substitution sub;
+
+  PredicateFunctionObject() {
+    this = pred.getASubstitutedType(sub) and
+    operator.getDeclaringType() = this and
+    operator.getName() = "operator()"
+  }
+
+  /**
+   * Get the predicate type parameter that this function object is being substituted for.
+   */
+  PredicateType getPredicateType() { result = pred }
+
+  /**
+   * Get the `operator()` function that this function object defines. This is the function that will
+   * be invoked and essentially defines the predicate behavior.
+   */
+  Function getCallOperator() { result = operator }
+
+  /**
+   * Get the `Substitution` object that makes this type a `PredicateFunctionObject`.
+   *
+   * This is a particular instantiation of some template that contains a predicate type parameter,
+   * which is substituted by this type in that instantiation. The `Substitution` object may refer
+   * to a `TemplateClass`, `TemplateVariable`, or `TemplateFunction`.
+   */
+  Substitution getSubstitution() { result = sub }
+}
+
+/**
+ * Gets a function access where the purpose of that access is to pass the accessed function as a
+ * predicate argument to a standard library template.
+ *
+ * For example, in `std::sort(..., ..., myCompare)`, where `myCompare` is a function, then
+ * `myCompare` will be converted into a function pointer and that function pointer will be used as
+ * a predicate in that `std::sort` call.
+ *
+ * This is more complex to identify than `PredicateFunctionObject` because the addressee of the
+ * function pointer is not necessarily statically known.
+ */
+class PredicateFunctionPointerUse extends FunctionAccess {
+  Expr functionPointerArgument;
+  FunctionCall templateFunctionCall;
+  FunctionTemplateInstantiation instantiation;
+  Substitution sub;
+  PredicateType pred;
+  Parameter parameter;
+  int index;
+
+  PredicateFunctionPointerUse() {
+    functionPointerArgument = templateFunctionCall.getArgument(index) and
+    templateFunctionCall.getTarget() = instantiation and
+    parameter = instantiation.getParameter(index) and
+    sub.asFunctionSubstitution() = instantiation and
+    parameter.getType() = sub.getSubstitutedTypeForParameter(pred) and
+    exists(DataFlow::Node func, DataFlow::Node arg |
+      func.asExpr() = this and
+      arg.asExpr() = functionPointerArgument and
+      DataFlow::localFlow(func, arg)
+    )
+  }
+
+  /**
+   * Get the predicate type parameter that this function pointer is being substituted for.
+   */
+  PredicateType getPredicateType() { result = pred }
+}

cpp/common/src/codingstandards/cpp/types/Templates.qll

@@ -0,0 +1,80 @@
+import cpp
+
+private newtype TSubstitution =
+  TClassSubstitution(ClassTemplateInstantiation cti) or
+  TFunctionSubstitution(FunctionTemplateInstantiation fti) or
+  TVariableSubstitution(VariableTemplateInstantiation vti)
+
+/**
+ * A class to facilitate working with template substitutions, especially since templates may be a
+ * `TemplateClass`, `TemplateFunction`, or `TemplateVariable`, which complicates their usage.
+ *
+ * A `Substitution` in particular refers to an instantiation of that template of some kind, and
+ * allows analysis of which parameters were substituted with which types in that instatiation.
+ */
+class Substitution extends TSubstitution {
+  ClassTemplateInstantiation asClassSubstitution() { this = TClassSubstitution(result) }
+
+  FunctionTemplateInstantiation asFunctionSubstitution() { this = TFunctionSubstitution(result) }
+
+  VariableTemplateInstantiation asVariableSubstitution() { this = TVariableSubstitution(result) }
+
+  /**
+   * Get the nth template parameter type of the template that is being substituted.
+   *
+   * For example, in `std::vector<int>`, the 0th template parameter is `typename T`.
+   */
+  TypeTemplateParameter getTemplateParameter(int index) {
+    result = this.asClassSubstitution().getTemplate().getTemplateArgument(index) or
+    result = this.asFunctionSubstitution().getTemplate().getTemplateArgument(index) or
+    result = this.asVariableSubstitution().getTemplate().getTemplateArgument(index)
+  }
+
+  /**
+   * Get the type that is substituting the nth template parameter in this substitution.
+   *
+   * For example, in `std::vector<int>`, the 0th substituted type is `int`.
+   */
+  Type getSubstitutedType(int index) {
+    result = this.asClassSubstitution().getTemplateArgument(index) or
+    result = this.asFunctionSubstitution().getTemplateArgument(index) or
+    result = this.asVariableSubstitution().getTemplateArgument(index)
+  }
+
+  /**
+   * Get the type that is substituting the given template parameter in this substitution.
+   *
+   * For example, in `std::vector<int>`, this predicate matches the given type `int` with the type
+   * parameter `typename T`.
+   */
+  Type getSubstitutedTypeForParameter(TypeTemplateParameter param) {
+    exists(int idx |
+      this.getTemplateParameter(idx) = param and
+      result = this.getSubstitutedType(idx)
+    )
+  }
+
+  string toString() {
+    result = this.asClassSubstitution().toString() or
+    result = this.asFunctionSubstitution().toString() or
+    result = this.asVariableSubstitution().toString()
+  }
+
+  /**
+   * Get a `Locatable` that represents a where this substitution was declared in the source code.
+   *
+   * The result may be a `TypeMention`, `Call`, etc. depending on the kind of template and how it is
+   * being used, but it handles the various template cases for you.
+   *
+   * Note that this instantiation may have been declared in multiple places.
+   */
+  Locatable getASubstitutionSite() {
+    result.(TypeMention).getMentionedType() = this.asClassSubstitution()
+    or
+    result.(Call).getTarget() = this.asFunctionSubstitution()
+    or
+    result.(FunctionAccess).getTarget() = this.asFunctionSubstitution()
+    or
+    result.(VariableAccess).getTarget() = this.asVariableSubstitution()
+  }
+}

cpp/common/test/includes/standard-library/deque.h

@@ -2,6 +2,7 @@
 #define _GHLIBCPP_DEQUE
 #include <iterator>
 #include <string>
+#include "memory.h"
 
 namespace std {
 template <class T, class Allocator = std::allocator<T>> class deque {

cpp/common/test/includes/standard-library/functional.h

@@ -90,5 +90,21 @@ template <class R, class... Args> class function<R(Args...)> {
   template <class F> function(F &&);
   template <class F> function &operator=(F &&);
 };
+
+template <typename T>
+struct less {
+  bool operator()(const T &x, const T &y) const;
+  typedef T first_argument_type;
+  typedef T second_argument_type;
+  typedef bool result_type;
+};
+
+template <typename T>
+struct greater {
+  bool operator()(const T &x, const T &y) const;
+  typedef T first_argument_type;
+  typedef T second_argument_type;
+  typedef bool result_type;
+};
 } // namespace std
 #endif

cpp/common/test/includes/standard-library/iosfwd.h

@@ -1,5 +1,6 @@
 #ifndef _GHLIBCPP_IOSFWD
 #define _GHLIBCPP_IOSFWD
+#include "memory.h"
 namespace std {
 template <class charT> class char_traits;
 template <> class char_traits<char>;

cpp/common/test/includes/standard-library/map

@@ -1,5 +1,6 @@
 #include "iterator.h"
-#include <bits/stl_function.h>
+#include "memory.h"
+#include "functional.h"
 
 namespace std {
 

cpp/common/test/includes/standard-library/memory.h

@@ -128,6 +128,12 @@ class bad_alloc : public exception {
   bad_alloc &operator=(const bad_alloc &) noexcept;
   virtual const char *what() const noexcept;
 };
+
+template <class T> class allocator {
+public:
+  allocator() throw();
+  typedef size_t size_type;
+};
 } // namespace std
 
 #endif // _GHLIBCPP_MEMORY

cpp/common/test/includes/standard-library/set

@@ -1,5 +1,6 @@
 #include "iterator.h"
-#include <bits/stl_function.h>
+#include "memory.h"
+#include "functional.h"
 
 namespace std {
 template <typename _Key, typename _Compare = std::less<_Key>,

cpp/common/test/includes/standard-library/string

@@ -1,6 +1,7 @@
 #ifndef _GHLIBCPP_STRING
 #define _GHLIBCPP_STRING
 #include "cwchar"
+#include "memory.h"
 #include "initializer_list"
 #include "ios.h"
 #include "iosfwd.h"
@@ -88,12 +89,6 @@ template <> struct char_traits<wchar_t> {
   static int_type eof();
 };
 
-template <class T> class allocator {
-public:
-  allocator() throw();
-  typedef size_t size_type;
-};
-
 template <class charT, class traits = char_traits<charT>,
           class Allocator = allocator<charT>>
 class basic_string {

cpp/common/test/includes/standard-library/vector.h

@@ -2,6 +2,7 @@
 #define _GHLIBCPP_VECTOR
 #include <iterator>
 #include <string>
+#include "memory.h"
 
 namespace std {