Preprocessor6: add DIR-4-9

Author: knewbury01

.vscode/tasks.json

@@ -251,6 +251,7 @@
                 "Preprocessor3",
                 "Preprocessor4",
                 "Preprocessor5",
+                "Preprocessor6",
                 "IntegerConversion",
                 "Expressions",
                 "DeadCode",

c/misra/src/rules/DIR-4-9/FunctionOverFunctionLikeMacro.ql

@@ -0,0 +1,73 @@
+/**
+ * @id c/misra/function-over-function-like-macro
+ * @name DIR-4-9: A function should be used in preference to a function-like macro where they are interchangeable
+ * @description Using a function-like macro instead of a function can lead to unexpected program
+ *              behaviour.
+ * @kind problem
+ * @precision medium
+ * @problem.severity recommendation
+ * @tags external/misra/id/dir-4-9
+ *       external/cert/audit
+ *       maintainability
+ *       readability
+ *       external/misra/obligation/advisory
+ */
+
+import cpp
+import codingstandards.c.misra
+import codingstandards.cpp.FunctionLikeMacro
+import codingstandards.cpp.Naming
+
+predicate isOperator(string possible) {
+  possible in [
+      "+", "-", "*", "/", "%", "^", "&", "|", "~", "!", "=", "<", ">", "+=", "-=", "*=", "/=", "%=",
+      "^=", "&=", "|=", "<<", ">>", ">>=", "<<=", "==", "!=", "<=", ">=", "<=>", "&&", "||", "++",
+      "--", "->*", "->", "()", "[]"
+    ]
+}
+
+//cases where we trust the choice
+predicate omission(MacroInvocation i) {
+  i.getFile() instanceof HeaderFile or
+  Naming::Cpp14::hasStandardLibraryMacroName(i.getMacroName())
+}
+
+class UnsafeMacro extends FunctionLikeMacro {
+  UnsafeMacro() {
+    //parameter not used - has false positives on args that are not used but are substrings of other args
+    exists(string p |
+      p = this.getAParameter() and
+      not this.getBody().regexpMatch(".*(\\s*|\\(||\\))" + p + "(\\s*||\\)|\\().*")
+    )
+    or
+    //parameter used more than once
+    exists(string p |
+      p = this.getAParameter() and
+      exists(int i, string newstr |
+        newstr = this.getBody().replaceAll(p, "") and
+        i = ((this.getBody().length() - newstr.length()) / p.length()) and
+        i > 1
+      )
+    )
+  }
+}
+
+from MacroInvocation i
+where
+  not isExcluded(i, Preprocessor6Package::functionOverFunctionLikeMacroQuery()) and
+  not omission(i) and
+  i.getMacro() instanceof UnsafeMacro and
+  //heuristic - macros with one arg only are easier to replace
+  not exists(i.getUnexpandedArgument(1)) and
+  //operator as arg omits function applicability
+  not isOperator(i.getUnexpandedArgument(_)) and
+  //static storage duration can only be initialized with constant
+  not exists(StaticStorageDurationVariable v | i.getExpr() = v.getAnAssignedValue()) and
+  //function call not allowed in a constant expression (where constant expr is parent)
+  not exists(Expr e |
+    e.isConstant() and
+    not i.getExpr() = e and
+    i.getExpr().getParent+() = e
+  ) and
+  forall(string arg | arg = i.getUnexpandedArgument(_) | exists(Expr e | arg = e.toString()))
+select i, "Macro invocation used when function call would be preferred."

c/misra/test/rules/DIR-4-9/FunctionOverFunctionLikeMacro.expected

@@ -0,0 +1 @@
+| test.c:19:12:19:20 | MACRO4(L) | Macro invocation used when function call would be preferred. |

c/misra/test/rules/DIR-4-9/FunctionOverFunctionLikeMacro.qlref

@@ -0,0 +1 @@
+rules/DIR-4-9/FunctionOverFunctionLikeMacro.ql

c/misra/test/rules/DIR-4-9/test.c

@@ -0,0 +1,24 @@
+#define MACRO(OP, L, R) ((L)OP(R))
+#define MACRO2(L, R) (L + R)
+#define MACRO3(L, R) (L + R + L)
+#define MACRO4(L) (1 + 1)
+#define MACRO5(L, LR) (LR + 1)
+#define MACRO6(X, LR) (LR + 1)
+
+const char a1[MACRO2(1, 1) + 6]; // COMPLIANT
+
+void f() {
+  int i = MACRO(+, 1, 1); // COMPLIANT
+
+  int i2 = MACRO2(7, 10); // COMPLIANT - exception
+
+  static i3 = MACRO2(1, 1); // COMPLIANT
+
+  int i4 = MACRO3(7, 10); // COMPLIANT - exception
+
+  int i5 = MACRO4(1); // NON_COMPLIANT
+
+  int i6 = MACRO5(1, 1); // NON_COMPLIANT[FALSE_NEGATIVE]
+
+  int i7 = MACRO6(1, 1); // COMPLIANT - exception
+}

cpp/common/src/codingstandards/cpp/exclusions/c/Preprocessor6.qll

@@ -0,0 +1,25 @@
+//** THIS FILE IS AUTOGENERATED, DO NOT MODIFY DIRECTLY.  **/
+import cpp
+import RuleMetadata
+import codingstandards.cpp.exclusions.RuleMetadata
+
+newtype Preprocessor6Query = TFunctionOverFunctionLikeMacroQuery()
+
+predicate isPreprocessor6QueryMetadata(Query query, string queryId, string ruleId) {
+  query =
+    // `Query` instance for the `functionOverFunctionLikeMacro` query
+    Preprocessor6Package::functionOverFunctionLikeMacroQuery() and
+  queryId =
+    // `@id` for the `functionOverFunctionLikeMacro` query
+    "c/misra/function-over-function-like-macro" and
+  ruleId = "DIR-4-9"
+}
+
+module Preprocessor6Package {
+  Query functionOverFunctionLikeMacroQuery() {
+    //autogenerate `Query` type
+    result =
+      // `Query` type for `functionOverFunctionLikeMacro` query
+      TQueryC(TPreprocessor6PackageQuery(TFunctionOverFunctionLikeMacroQuery()))
+  }
+}

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

@@ -25,6 +25,7 @@ import Preprocessor2
 import Preprocessor3
 import Preprocessor4
 import Preprocessor5
+import Preprocessor6
 import SideEffects1
 import SideEffects2
 import Strings1
@@ -57,6 +58,7 @@ newtype TCQuery =
   TPreprocessor3PackageQuery(Preprocessor3Query q) or
   TPreprocessor4PackageQuery(Preprocessor4Query q) or
   TPreprocessor5PackageQuery(Preprocessor5Query q) or
+  TPreprocessor6PackageQuery(Preprocessor6Query q) or
   TSideEffects1PackageQuery(SideEffects1Query q) or
   TSideEffects2PackageQuery(SideEffects2Query q) or
   TStrings1PackageQuery(Strings1Query q) or
@@ -89,6 +91,7 @@ predicate isQueryMetadata(Query query, string queryId, string ruleId) {
   isPreprocessor3QueryMetadata(query, queryId, ruleId) or
   isPreprocessor4QueryMetadata(query, queryId, ruleId) or
   isPreprocessor5QueryMetadata(query, queryId, ruleId) or
+  isPreprocessor6QueryMetadata(query, queryId, ruleId) or
   isSideEffects1QueryMetadata(query, queryId, ruleId) or
   isSideEffects2QueryMetadata(query, queryId, ruleId) or
   isStrings1QueryMetadata(query, queryId, ruleId) or

rule_packages/c/Preprocessor6.json

@@ -0,0 +1,25 @@
+{
+  "MISRA-C-2012": {
+    "DIR-4-9": {
+      "properties": {
+        "obligation": "advisory"
+      },
+      "queries": [
+        {
+          "description": "Using a function-like macro instead of a function can lead to unexpected program behaviour.",
+          "kind": "problem",
+          "name": "A function should be used in preference to a function-like macro where they are interchangeable",
+          "precision": "medium",
+          "severity": "recommendation",
+          "short_name": "FunctionOverFunctionLikeMacro",
+          "tags": [
+            "external/misra/audit",
+            "maintainability",
+            "readability"
+          ]
+        }
+      ],
+      "title": "A function should be used in preference to a function-like macro where they are interchangeable"
+    }
+  }
+}

rules.csv

@@ -610,7 +610,7 @@ c,MISRA-C-2012,DIR-4-5,Yes,Advisory,,,Identifiers in the same name space with ov
 c,MISRA-C-2012,RULE-4-6,Yes,Advisory,,,typedefs that indicate size and signedness should be used in place of the basic numerical types,,Types,Hard,
 c,MISRA-C-2012,RULE-4-7,Yes,Required,,,"If a function returns error information, then that error information shall be tested",M0-3-2,Contracts,Import,
 c,MISRA-C-2012,RULE-4-8,Yes,Advisory,,,"If a pointer to a structure or union is never dereferenced within a translation unit, then the implementation of the object should be hidden",,Pointers1,Medium,
-c,MISRA-C-2012,RULE-4-9,Yes,Advisory,,,A function should be used in preference to a function-like macro where they are interchangeable,,Preprocessor,Medium,
+c,MISRA-C-2012,DIR-4-9,Yes,Advisory,,,A function should be used in preference to a function-like macro where they are interchangeable,,Preprocessor6,Medium,Audit
 c,MISRA-C-2012,RULE-4-10,Yes,Required,,,Precautions shall be taken in order to prevent the contents of a header file being included more than once,M16-2-3,Preprocessor2,Medium,
 c,MISRA-C-2012,RULE-4-11,Yes,Required,,,The validity of values passed to library functions shall be checked,,Contracts,Hard,
 c,MISRA-C-2012,RULE-4-12,Yes,Required,,,Dynamic memory allocation shall not be used,,Banned,Medium,