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Commit 712d76e

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knewbury01knewbury01
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Declarations7: add RULE-18-8
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‎c/misra/src/rules/RULE-18-8/VariableLengthArrayTypesUsed.ql

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/**
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* @id c/misra/variable-length-array-types-used
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* @name RULE-18-8: Variable-length array types shall not be used
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* @description Using a variable length array can lead to unexpected or undefined program behaviour.
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* @kind problem
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* @precision very-high
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* @problem.severity error
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* @tags external/misra/id/rule-18-8
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* correctness
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* readability
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* external/misra/obligation/required
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*/
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import cpp
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import codingstandards.c.misra
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predicate partOfConstantExpr(MacroInvocation i) {
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exists(Expr e |
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e.isConstant() and
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not i.getExpr() = e and
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i.getExpr().getParent+() = e
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)
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}
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/**
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* A variable length array (VLA)
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* ie an array where the size
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* is not an integer constant expression
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*/
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class VariableLengthArray extends VariableDeclarationEntry {
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VariableLengthArray() {
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//VLAs will not have: static/extern specifiers (compilation error)
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not this.hasSpecifier("static") and
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not this.hasSpecifier("extern") and
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//VLAs are not allowed to be initialized
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not this.getDeclaration().hasInitializer() and
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exists(ArrayType a |
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//a.hasArraySize() does not catch multidimensional VLAs like a[1][]
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a.toString().matches("%[]%") and
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this.getUnspecifiedType() = a and
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//variable length array is one declared in block or function prototype
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(
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this.getDeclaration().getParentScope() instanceof Function or
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this.getDeclaration().getParentScope() instanceof BlockStmt
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)
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)
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}
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}
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from VariableLengthArray v
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where
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not isExcluded(v, Declarations7Package::variableLengthArrayTypesUsedQuery()) and
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//an exception, argv in : int main(int argc, char *argv[])
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not v.getDeclaration().getParentScope().(Function).hasName("main")
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select v, "Variable length array declared."

‎c/misra/test/rules/RULE-18-8/VariableLengthArrayTypesUsed.expected

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WARNING: Unused predicate partOfConstantExpr (/Users/knewbury/Desktop/GITHUB/coding-standards/codeql-coding-standards/c/misra/src/rules/RULE-18-8/VariableLengthArrayTypesUsed.ql:17,11-29)
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| test.c:3:19:3:20 | definition of pa | Variable length array declared. |
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| test.c:6:7:6:8 | definition of a1 | Variable length array declared. |
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| test.c:7:7:7:8 | definition of a2 | Variable length array declared. |
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| test.c:8:7:8:8 | definition of a3 | Variable length array declared. |
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| test.c:14:20:14:21 | definition of pa | Variable length array declared. |

‎c/misra/test/rules/RULE-18-8/VariableLengthArrayTypesUsed.qlref

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+1Lines changed: 1 addition & 0 deletions
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rules/RULE-18-8/VariableLengthArrayTypesUsed.ql

‎c/misra/test/rules/RULE-18-8/test.c

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#define TEST 1
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void f(int n, int pa[1][n]) { // NON_COMPLIANT
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int a[1]; // COMPLIANT
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int x = 1;
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int a1[1 + x]; // NON_COMPLIANT - not integer constant expr
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int a2[n]; // NON_COMPLIANT
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int a3[1][n]; // NON_COMPLIANT
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int a4[] = {1}; // COMPLIANT - not a VLA
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int a5[TEST]; // COMPLIANT
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int a6[1 + 1]; // COMPLIANT
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}
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void f1(int n, int pa[n]) { // NON_COMPLIANT
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}

‎cpp/common/src/codingstandards/cpp/exclusions/c/Declarations7.qll

Copy file name to clipboardExpand all lines: cpp/common/src/codingstandards/cpp/exclusions/c/Declarations7.qll
+19-1Lines changed: 19 additions & 1 deletion
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@@ -3,9 +3,20 @@ import cpp
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import RuleMetadata
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import codingstandards.cpp.exclusions.RuleMetadata
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newtype Declarations7Query = TValueImplicitEnumerationConstantNotUniqueQuery()
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newtype Declarations7Query =
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TVariableLengthArrayTypesUsedQuery() or
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TValueImplicitEnumerationConstantNotUniqueQuery()
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predicate isDeclarations7QueryMetadata(Query query, string queryId, string ruleId, string category) {
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query =
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// `Query` instance for the `variableLengthArrayTypesUsed` query
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Declarations7Package::variableLengthArrayTypesUsedQuery() and
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queryId =
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// `@id` for the `variableLengthArrayTypesUsed` query
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"c/misra/variable-length-array-types-used" and
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ruleId = "RULE-18-8" and
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category = "required"
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or
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query =
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// `Query` instance for the `valueImplicitEnumerationConstantNotUnique` query
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Declarations7Package::valueImplicitEnumerationConstantNotUniqueQuery() and
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}
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module Declarations7Package {
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Query variableLengthArrayTypesUsedQuery() {
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//autogenerate `Query` type
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result =
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// `Query` type for `variableLengthArrayTypesUsed` query
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TQueryC(TDeclarations7PackageQuery(TVariableLengthArrayTypesUsedQuery()))
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}
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Query valueImplicitEnumerationConstantNotUniqueQuery() {
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//autogenerate `Query` type
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result =

‎rule_packages/c/Declarations7.json

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{
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"MISRA-C-2012": {
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"RULE-18-8": {
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"properties": {
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"obligation": "required"
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},
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"queries": [
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{
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"description": "Using a variable length array can lead to unexpected or undefined program behaviour.",
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"kind": "problem",
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"name": "Variable-length array types shall not be used",
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"precision": "very-high",
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"severity": "error",
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"short_name": "VariableLengthArrayTypesUsed",
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"tags": [
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"correctness",
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"readability"
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]
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}
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],
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"title": "Variable-length array types shall not be used"
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},
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"RULE-8-12": {
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"properties": {
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"obligation": "required"

‎rules.csv

Copy file name to clipboardExpand all lines: rules.csv
+1-1Lines changed: 1 addition & 1 deletion
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@@ -726,7 +726,7 @@ c,MISRA-C-2012,RULE-18-4,Yes,Advisory,,,"The +, -, += and -= operators should no
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c,MISRA-C-2012,RULE-18-5,Yes,Advisory,,,Declarations should contain no more than two levels of pointer nesting,A5-0-3,Pointers1,Import,
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c,MISRA-C-2012,RULE-18-6,Yes,Required,,,The address of an object with automatic storage shall not be copied to another object that persists after the first object has ceased to exist,M7-5-2,Pointers1,Import,
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c,MISRA-C-2012,RULE-18-7,Yes,Required,,,Flexible array members shall not be declared,,Declarations,Medium,
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c,MISRA-C-2012,RULE-18-8,Yes,Required,,,Variable-length array types shall not be used,,Declarations,Medium,
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c,MISRA-C-2012,RULE-18-8,Yes,Required,,,Variable-length array types shall not be used,,Declarations7,Medium,
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c,MISRA-C-2012,RULE-19-1,Yes,Mandatory,,,An object shall not be assigned or copied to an overlapping object,M0-2-1,Contracts,Hard,
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c,MISRA-C-2012,RULE-19-2,Yes,Advisory,,,The union keyword should not be used,A9-5-1,Banned,Import,
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c,MISRA-C-2012,RULE-20-1,Yes,Advisory,,,#include directives should only be preceded by preprocessor directives or comments,M16-0-1,Preprocessor1,Import,

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