P4::P4Tools::P4Testgen::Continuation Class Reference

#include <continuation.h>

Classes
class	Body
	A continuation body is a list of commands. More...
struct	Guard
class	Parameter
struct	PropertyUpdate
struct	Return

Public Types
using	Command
enum class	Exception {   Exit , NoMatch , Reject , Drop ,   PacketTooShort , Abort }
	Enumerates the exceptions that can be thrown during symbolic execution. More...
using	PropertyValue = std::variant<cstring, uint64_t, int64_t, bool, const IR::Expression *>

Public Member Functions
	Continuation (Body body)
	Creates a parameterless continuation.
	Continuation (std::optional< const Parameter * > parameterOpt, Body body)
Body	apply (std::optional< const IR::Node * > value_opt) const

Static Public Member Functions
static const Parameter *	genParameter (const IR::Type *type, cstring name, const NamespaceContext *ctx)

Public Attributes
Body	body
std::optional< const IR::PathExpression * >	parameterOpt
	Represents the continuation's parameter.

Friends
std::ostream &	operator<< (std::ostream &out, const Exception value)

Detailed Description

A continuation is a function that optionally takes an argument and executes a sequence of commands.

Member Typedef Documentation

Command

using P4::P4Tools::P4Testgen::Continuation::Command

Initial value:

 std::variant<
        
        const IR::Node *,
        
        const TraceEvent *,
        
        Return,
        
        Exception,
        
        PropertyUpdate,
        
        Guard>

PropertyValue

using P4::P4Tools::P4Testgen::Continuation::PropertyValue = std::variant<cstring, uint64_t, int64_t, bool, const IR::Expression *>

Alias for various property types that can be set. We restrict these to keep the feature simple.

Member Enumeration Documentation

Exception

enum class P4::P4Tools::P4Testgen::Continuation::Exception

strong

Enumerates the exceptions that can be thrown during symbolic execution.

Enumerator
Exit	Thrown when an exit statement is encountered.
NoMatch	Thrown when a select expression fails to match. This models P4's error.NoMatch.
Reject	Thrown when the parser reaches the reject state.
Drop	This is an internal interpreter exception to express drop semantics.
PacketTooShort	Thrown on premature packet end. Models P4's error.PacketTooShort.
Abort	Thrown when the target terminates.

Constructor & Destructor Documentation

Continuation()

P4::P4Tools::P4Testgen::Continuation::Continuation ( std::optional< const Parameter * > parameterOpt, Body body )

inline

Creates a continuation. The continuation will have the given parameter, if one is provided; otherwise, the continuation will have no parameters.

Member Function Documentation

apply()

Continuation::Body P4::P4Tools::P4Testgen::Continuation::apply

(

std::optional< const IR::Node * >

value_opt

)

const

Returns

a body that is equivalent to applying this continuation to the given value (or unit, if no value is provided). A BUG occurs if parameterOpt is std::nullopt but value_opt is not, or vice versa.

Expressions in the metalanguage include P4 non-expressions. Because of this, the value (if provided) does not necessarily need to be an instance of IR::Expression.

Creates a visitor for Commands that substitutes the given value for the given parameter.

genParameter()

const Continuation::Parameter * P4::P4Tools::P4Testgen::Continuation::genParameter ( const IR::Type * type, cstring name, const NamespaceContext * ctx )

static

Returns

a parameter for use in building continuations. The parameter will be fresh in the given @ctx.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream & out, const Exception value )

friend

A helper function to print the string values of the exception enum. Unfortunately, this is a little clunky to use an maintain because we have to add new enum fields manually. TODO: Find a better implementation to print enums. Also use constexpr instead.