#include <remove_set_metadata.h>

Inheritance diagram for BFN::RemoveSetMetadata:

Public Member Functions
	RemoveSetMetadata (P4::ReferenceMap refMap, P4::TypeMap typeMap)

const IR::AssignmentStatement *	preorder (IR::AssignmentStatement *assignment)

Public Member Functions inherited from P4::Transform
const IR::Node *	apply_visitor (const IR::Node , const char name=0) override

profile_t	init_apply (const IR::Node *root) override

virtual void	loop_revisit (const IR::Node *)

virtual const IR::Node *	postorder (IR::Node *n)

virtual const IR::Node *	preorder (IR::Node *n)

void	prune ()

virtual void	revisit (const IR::Node , const IR::Node )

void	revisit_visited ()

bool	visit_in_progress (const IR::Node *) const

void	visitAgain () const override

void	visitOnce () const override

Public Member Functions inherited from P4::Visitor
virtual bool	check_global (cstring)

virtual void	clear_globals ()

virtual Visitor *	clone () const

virtual ControlFlowVisitor *	controlFlowVisitor ()

virtual void	end_apply ()

virtual void	end_apply (const IR::Node *root)

virtual void	erase_global (cstring)

template<class T >
const T *	findContext () const

template<class T >
const T *	findContext (const Context *&c) const

template<class T >
const T *	findOrigCtxt () const

template<class T >
const T *	findOrigCtxt (const Context *&c) const

virtual Visitor &	flow_clone ()

virtual void	flow_merge (Visitor &)

virtual bool	flow_merge_closure (Visitor &)

virtual void	flow_merge_global_from (cstring)

virtual void	flow_merge_global_to (cstring)

const Context *	getChildContext () const

int	getChildrenVisited () const

const Context *	getContext () const

int	getContextDepth () const

const IR::Node *	getCurrentNode () const

template<class T >
const T *	getCurrentNode () const

const IR::Node *	getOriginal () const

template<class T >
const T *	getOriginal () const

template<class T >
const T *	getParent () const

virtual bool	has_flow_joins () const

profile_t	init_apply (const IR::Node root, const Context parent_context)

bool	isInContext (const IR::Node *n) const

virtual const char *	name () const

template<class T >
void	parallel_visit (const IR::Vector< T > &v, const char *name, int cidx)

template<class T >
void	parallel_visit (const IR::Vector< T > &v, const char *name=0)

template<class T >
void	parallel_visit (IR::Vector< T > &v, const char *name, int cidx)

template<class T >
void	parallel_visit (IR::Vector< T > &v, const char *name=0)

void	print_context () const

const Visitor &	setCalledBy (const Visitor *visitor)

void	setName (const char *name)

void	visit (const IR::Node &n, const char *name, int cidx)

void	visit (const IR::Node &n, const char *name=0)

void	visit (const IR::Node &n, const char name, int cidx)

void	visit (const IR::Node &n, const char name=0)

void	visit (const IR::Node const &n, const char name, int cidx)

void	visit (const IR::Node const &n, const char name=0)

void	visit (IR::Node &n, const char *name, int cidx)

void	visit (IR::Node &n, const char *name=0)

void	visit (IR::Node &, const char =0, int=0)

template<class T , typename = std::enable_if_t<Util::has_SourceInfo_v<T> && !std::is_pointer_v<T>>, class... Args>
void	warn (const int kind, const char *format, const T &node, Args &&...args)
	The const ref variant of the above.

template<class T , typename = std::enable_if_t<Util::has_SourceInfo_v<T>>, class... Args>
void	warn (const int kind, const char format, const T node, Args &&...args)

bool	warning_enabled (int warning_kind) const

Additional Inherited Members
Public Types inherited from P4::Visitor
typedef Visitor_Context	Context

Static Public Member Functions inherited from P4::Visitor
static cstring	demangle (const char *)

static bool	warning_enabled (const Visitor *visitor, int warning_kind)

Public Attributes inherited from P4::Visitor
const Visitor *	called_by = nullptr

cstring	internalName

SplitFlowVisit_base *&	split_link

SplitFlowVisit_base *	split_link_mem = nullptr

Protected Member Functions inherited from P4::Transform
const IR::Node *	transform_child (const IR::Node *child)

Protected Member Functions inherited from P4::Visitor
virtual void	init_join_flows (const IR::Node *)

virtual bool	join_flows (const IR::Node *)

virtual void	post_join_flows (const IR::Node , const IR::Node )

void	visit_children (const IR::Node *, std::function< void()> fn)

Protected Attributes inherited from P4::Transform
bool	forceClone = false

Protected Attributes inherited from P4::Visitor
bool	dontForwardChildrenBeforePreorder = false

bool	joinFlows = false

bool	visitDagOnce = true

Detailed Description

Removes assignments to metadata fields in the egress parser.

In v1model, the values metadata fields have at the end of the ingress thread are serialized into a hidden header which is sent to the egress thread along with the real packet. That hidden header is then deserialized to initialize the same metadata fields in the egress thread. These metadata fields are collectively called "bridged metadata".

This process can introduce conflicts if the bridged fields are also written to elsewhere in the egress parser. Since the user can't write their own egress parser in v1model, the compiler has to be responsible for dealing with this problem. We eliminate the potential for conflict by removing assignments to metadata fields from the egress parser.

There is one exception to the rule: writes to metadata which is declared local to the parser isn't removed. Because such metadata doesn't escape the parser, it couldn't be bridged in any case, and removing it would unnecessarily restrict both the user and the transformations that the compiler can perform.

Precondition: All parsers are inlined, the program has been transformed to use the TNA architecture, and the refMap is current.

Postcondition: Assignments to non-parser-local metadata fields are removed from the egress parser.

Public Member Functions

Additional Inherited Members

Detailed Description