Skip to content

cpp_ast.prompt.md

Latest commit

 

History

History
238 lines (183 loc) · 9.56 KB

cpp_ast.prompt.md

File metadata and controls

238 lines (183 loc) · 9.56 KB
description CodeQL AST node reference for the C++ language

CodeQL AST nodes for cpp language

CodeQL's core AST classes for cpp language

Based on comprehensive analysis of CodeQL's C++ AST test results from both local and GitHub test files, here are the core AST classes for C/C++ analysis:

Function and Method Declarations

Function Types:

  • TopLevelFunction - Global functions (e.g., void fun3(someClass*), int main())
  • MemberFunction - Class member functions (e.g., void someClass::f(), int someClass::g(int, int))
  • VirtualFunction - Virtual functions with dynamic dispatch (e.g., virtual void Base::v())
  • ConstMemberFunction - Const member functions (e.g., char const* std::type_info::name() const)
  • FormattingFunction - Functions with format string checking (e.g., int printf(char const*))
  • TemplateFunction - Template function declarations

Constructors and Destructors:

  • Constructor - Class constructors (e.g., void C::C(int))
  • CopyConstructor - Copy constructors (e.g., void C::C(C const&))
  • CopyAssignmentOperator - Copy assignment operators (e.g., C& C::operator=(C const&))
  • MoveAssignmentOperator - Move assignment operators (e.g., C& C::operator=(C&&))
  • Destructor - Destructor declarations
  • DestructorCall - Explicit and implicit destructor calls (e.g., call to ~C)

Operator Functions:

  • Operator - Operator overloads (e.g., void operator delete(void*), void* operator new(unsigned long))

Statements

Control Flow Statements:

  • BlockStmt - Block statements containing multiple statements (e.g., { ... })
  • IfStmt - Conditional statements with condition and branches
  • ForStmt - For loops with initialization, condition, and increment
  • ReturnStmt - Return statements with optional expressions
  • GotoStmt - Goto statements for jumping to labels
  • LabelStmt - Label statements for goto targets

Declaration Statements:

  • DeclStmt - Declaration statements containing variable and type declarations
  • VariableDeclarationEntry - Individual variable declarations (e.g., definition of i)
  • TypeDeclarationEntry - Type declarations (e.g., definition of u)

Expression Statements:

  • ExprStmt - Statement wrappers for expressions

Variable Length Array Support:

  • VlaDimensionStmt - VLA dimension size statements
  • VlaDeclStmt - VLA declaration statements

Expressions

Primary Expressions:

  • Literal - Literal values (e.g., 1, 2, 42, "hello")
  • StringLiteral - String literals (e.g., "int", "string")
  • VariableAccess - Variable references (e.g., sc, i, args)
  • ThisExpr - The this keyword in member functions

Function Calls:

  • FunctionCall - Function calls (e.g., call to f, call to printf)
  • FormattingFunctionCall - Calls to format string functions with type checking
  • MethodCall - Method calls on objects
  • ConstructorCall - Constructor calls (e.g., call to C)

Operators and Assignments:

  • AssignExpr - Assignment expressions (e.g., ... = ...)
  • AddExpr - Addition expressions (e.g., ... + ...)
  • MulExpr - Multiplication expressions (e.g., ... * ...)
  • SubExpr - Subtraction expressions

Object Creation and Destruction:

  • ClassInstanceExpr - Object instantiation expressions
  • NewExpr - Dynamic memory allocation with new
  • DeleteExpr - Dynamic memory deallocation with delete
  • VacuousDestructorCall - Vacuous destructor calls for trivial types

Array and Pointer Operations:

  • ArrayExpr - Array access expressions (e.g., access to array)
  • PointerDereferenceExpr - Pointer dereference (e.g., * ...)
  • AddressOfExpr - Address-of operator (e.g., & ...)
  • ArrayToPointerConversion - Implicit array to pointer conversions

Field Access:

  • ValueFieldAccess - Value-based field access (e.g., obj.field)
  • PointerFieldAccess - Pointer-based field access (e.g., ptr->field)

Type Casting:

  • CStyleCast - C-style casts (e.g., (int)..., (char)...)
  • StaticCast - Static casts for safe conversions
  • DynamicCast - Dynamic casts for runtime type checking (e.g., dynamic_cast<Derived *>...)
  • ConstCast - Const casts (e.g., const_cast<T *>...)
  • ReinterpretCast - Reinterpret casts (e.g., reinterpret_cast<S *>...)

Reference Operations:

  • ReferenceToExpr - Reference creation (e.g., (reference to))
  • ReferenceDereferenceExpr - Reference dereference (e.g., (reference dereference))

Type Information:

  • TypeidOperator - Runtime type information (e.g., typeid ...)

Modern C++ Features:

  • ParenthesizedExpr - Parenthesized expressions for grouping

Type System

Basic Types:

  • IntType - Integer types (e.g., int)
  • VoidType - Void type
  • FloatType - Floating-point types
  • LongType - Long integer types (e.g., unsigned long)
  • PlainCharType - Plain char type
  • CharType - Character types

Pointer Types:

  • PointerType - Pointer types (e.g., someClass *, Base *)
  • IntPointerType - Integer pointer types (e.g., int *)
  • CharPointerType - Character pointer types (e.g., char *)
  • VoidPointerType - Void pointer types (e.g., void *)
  • FunctionPointerType - Function pointer types

Reference Types:

  • LValueReferenceType - L-value references (e.g., const someClass &)
  • RValueReferenceType - R-value references (e.g., someClass &&)

Array Types:

  • ArrayType - Array types (e.g., char[], char[4])

Class and Struct Types:

  • Class - Class types (e.g., Base, Derived)
  • Struct - Struct types
  • NestedClass - Nested class types
  • LocalUnion - Local union types

Template Types:

  • TypeTemplateParameter - Template type parameters (e.g., T)

Advanced Types:

  • SpecifiedType - Type qualifiers (e.g., const type_info)
  • CTypedefType - C typedef types (e.g., va_list, MYINT)

C11 Generic Support

Generic Expressions:

  • C11GenericExpr - C11 _Generic expressions for type-based selection
  • ReuseExpr - Expression reuse in generic contexts
  • TypeName - Type names in generic associations

Parameters and Initializers

Parameter Handling:

  • Parameter - Function parameters with types (e.g., i, j, sc)
  • Support for unnamed parameters and default arguments

Initialization:

  • Initializer - Variable initializers (e.g., initializer for i)
  • Constructor initialization lists
  • Field initialization

Built-in Functions

Variable Arguments:

  • BuiltInVarArgsStart - __builtin_va_start for variadic functions
  • BuiltInVarArgsEnd - __builtin_va_end for cleanup

Type Conversions

Implicit Conversions:

  • IntegralConversion - Integer type conversions
  • PointerConversion - Pointer type conversions
  • BaseClassConversion - Base class conversions for inheritance
  • GlvalueConversion - Glvalue conversions

Explicit Conversions:

  • Support for all cast types with conversion tracking
  • Value category preservation through conversions

Value Categories and Properties

Value Categories:

  • prvalue - Pure r-values (temporary values)
  • lvalue - L-values (addressable values)
  • prvalue(load) - Loaded values from memory

Type Properties:

  • Type information preservation through all expressions
  • Conversion tracking for type safety analysis

Example AST Hierarchy

Based on CodeQL's comprehensive C++ analysis capabilities:

TopLevelFunction (global functions)
├── Parameter (function parameters)
├── BlockStmt (function body)
│   ├── DeclStmt (declarations)
│   │   └── VariableDeclarationEntry (variable definitions)
│   ├── ExprStmt (expression statements)
│   │   ├── FunctionCall (function calls)
│   │   ├── AssignExpr (assignments)
│   │   └── VariableAccess (variable references)
│   └── ReturnStmt (return statements)
└── Type information (IntType, PointerType, etc.)

Class (class declarations)
├── Constructor/Destructor (special members)
├── MemberFunction (methods)
├── CopyAssignmentOperator (copy operations)
└── MoveAssignmentOperator (move operations)

Expression hierarchy with full type and conversion tracking
├── Primary expressions (literals, variables)
├── Operators (arithmetic, logical, comparison)
├── Casts (static, dynamic, const, reinterpret)
├── Object operations (new, delete, field access)
└── Type operations (sizeof, typeid, alignof)

Expected test results for local PrintAst.ql query

This repo contains a variant of the open-source PrintAst.ql query for cpp language, with modifications for local testing:

Expected test results for open-source PrintAst.ql query

The following links can be fetched to get the expected results for different unit tests of the open-source PrintAst.ql query for the cpp language: