P4C
The P4 Compiler
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RemoveMetadataInits Class Reference

#include <auto_init_metadata.h>

Inheritance diagram for RemoveMetadataInits:
[legend]

Public Member Functions

 RemoveMetadataInits (const PhvInfo &phv, const FieldDefUse &defuse, std::set< cstring > &zeroInitFields)
 
bool elim_extract (const IR::BFN::Unit *unit, const IR::BFN::Extract *extract) override
 Determines whether the given extract, occurring in the given unit, should be eliminated.
 
const IR::BFN::Pipe * preorder (IR::BFN::Pipe *pipe) override
 
const IR::MAU::Instruction * preorder (IR::MAU::Instruction *instr) override
 
- Public Member Functions inherited from P4::Transform
const IR::Nodeapply_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::Nodepostorder (IR::Node *n)
 
virtual const IR::Nodepreorder (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 Visitorclone () const
 
virtual ControlFlowVisitorcontrolFlowVisitor ()
 
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 Visitorflow_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 ContextgetChildContext () const
 
int getChildrenVisited () const
 
const ContextgetContext () const
 
int getContextDepth () const
 
const IR::NodegetCurrentNode () const
 
template<class T >
const T * getCurrentNode () const
 
const IR::NodegetOriginal () 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 VisitorsetCalledBy (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 Visitorcalled_by = nullptr
 
cstring internalName
 
SplitFlowVisit_base *& split_link
 
SplitFlowVisit_basesplit_link_mem = nullptr
 
- Protected Member Functions inherited from AbstractElimUnusedInstructions
 AbstractElimUnusedInstructions (const FieldDefUse &defuse)
 
const IR::BFN::Extract * preorder (IR::BFN::Extract *extract) override
 
const IR::BFN::FieldLVal * preorder (IR::BFN::FieldLVal *lval) override
 
const IR::GlobalRef * preorder (IR::GlobalRef *gr) override
 
const IR::MAU::StatefulAlu * preorder (IR::MAU::StatefulAlu *salu) override
 
- Protected Member Functions inherited from P4::Transform
const IR::Nodetransform_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 AbstractElimUnusedInstructions
const FieldDefUsedefuse
 
std::set< cstringeliminated
 Names of fields whose extracts have been eliminated.
 
- 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 unnecessary metadata initializations. An assignment to a metadata field is deemed an unnecessary initialization if it satisfies all of the following:

  • The metadata field is not annotated with @pa_no_init.
  • The metadata field is initially valid (
    See also
    PHV::Field::is_invalidate_from_arch).
  • The constant 0 is assigned.
  • The assignment only overwrites ImplicitParserInit, according to def-use.

Member Function Documentation

◆ elim_extract()

bool RemoveMetadataInits::elim_extract ( const IR::BFN::Unit * unit,
const IR::BFN::Extract * extract )
overridevirtual

Determines whether the given extract, occurring in the given unit, should be eliminated.

Implements AbstractElimUnusedInstructions.