P4C
The P4 Compiler
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LowerParser
Parser & deparser

Replace field-based parser and deparser IR with container-based parser and deparser IR. More...

Collaboration diagram for LowerParser:

Topics

 LowerDeparserIR
 Replace deparser IR with lowered version that references containers instead of fields.
 
 LowerParserIR
 Generates a lowered version of the parser IR in this program and swaps it in for the existing representation.
 

Classes

class  CharacterizeParser
 Prints various info about parser to the log file. More...
 
class  Parde::Lowered::ComputeBufferRequirements
 Computes the number of bytes which must be available for each parser match to avoid a stall. More...
 
class  Parde::Lowered::ComputeInitZeroContainers
 Computes containers that have fields relying on parser zero initialization. More...
 
class  Parde::Lowered::ComputeMultiWriteContainers
 Collects all containers that are written more than once by the parser. More...
 
class  Parde::Lowered::WarnTernaryMatchFields
 Issues warning for invalid container participating in ternary match. More...
 
class  PragmaNoInit
 Adds the no_init pragma to the specified fields with the specified gress. More...
 

Detailed Description

Replace field-based parser and deparser IR with container-based parser and deparser IR.

Replace the high-level parser and deparser IRs, which operate on fields and field-like objects, into the low-level IRs which operate on PHV containers and constants.

This is a lossy transformation; no information about fields remains in the lowered parser IR in a form that's useable by the rest of the compiler. For that reason, any analyses or transformations that need to take that information into account need to run before this pass.

Precondition
The parser and deparser IR have been simplified by ResolveComputedParserExpressions and PHV allocation has completed successfully.
Postcondition
The parser and deparser IR are replaced by lowered versions.

Class Documentation

◆ CharacterizeParser

class CharacterizeParser

Prints various info about parser to the log file.

Copyright (C) 2024 Intel Corporation

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

SPDX-License-Identifier: Apache-2.0

Inheritance diagram for CharacterizeParser:
[legend]

Public Member Functions

void end_apply (const IR::Node *root) override
 
void get_checksum_usage (const IR::BFN::LoweredParserMatch *match)
 
void get_clot_usage (const IR::BFN::LoweredParserMatch *match)
 
void get_extractor_usage (const IR::BFN::LoweredParserMatch *match)
 
Visitor::profile_t init_apply (const IR::Node *root) override
 
bool preorder (const IR::BFN::LoweredParserMatch *match) override
 
bool preorder (const IR::BFN::LoweredParserState *state) override
 
void print_parser_summary (const IR::BFN::LoweredParser *parser)
 
void print_state_usage (const IR::BFN::LoweredParser *parser)
 
void print_timing_report (const IR::BFN::LoweredParser *parser, const std::vector< const IR::BFN::LoweredParserState * > &path)
 
- Public Member Functions inherited from P4::Inspector
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 void postorder (const IR::Node *)
 
virtual bool preorder (const IR::Node *)
 
virtual void revisit (const IR::Node *)
 
void revisit_visited ()
 
bool visit_in_progress (const IR::Node *n) 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
 

Static Public Member Functions

static double round (double val, int decimal_point)
 
- Static Public Member Functions inherited from P4::Visitor
static cstring demangle (const char *)
 
static bool warning_enabled (const Visitor *visitor, int warning_kind)
 

Additional Inherited Members

- Public Types inherited from P4::Visitor
typedef Visitor_Context Context
 
- 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::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::Visitor
bool dontForwardChildrenBeforePreorder = false
 
bool joinFlows = false
 
bool visitDagOnce = true
 

◆ Parde::Lowered::ComputeBufferRequirements

class Parde::Lowered::ComputeBufferRequirements

Computes the number of bytes which must be available for each parser match to avoid a stall.

Inheritance diagram for Parde::Lowered::ComputeBufferRequirements:
[legend]

◆ Parde::Lowered::ComputeInitZeroContainers

class Parde::Lowered::ComputeInitZeroContainers

Computes containers that have fields relying on parser zero initialization.

These containers will be marked as valid coming out of the parser (Tofino only). In Tofino2, all containers are valid coming out of the parser.

Inheritance diagram for Parde::Lowered::ComputeInitZeroContainers:
[legend]

Public Member Functions

 ComputeInitZeroContainers (const PhvInfo &phv, const FieldDefUse &defuse, const ordered_set< const PHV::Field * > &no_init, const std::map< gress_t, std::set< PHV::Container > > &origParserZeroInitContainers)
 

Public Attributes

const FieldDefUse & defuse
 
const ordered_set< const PHV::Field * > & no_init_fields
 
const std::map< gress_t, std::set< PHV::Container > > & origParserZeroInitContainers
 
const PhvInfo & phv
 

◆ Parde::Lowered::ComputeMultiWriteContainers

class Parde::Lowered::ComputeMultiWriteContainers

Collects all containers that are written more than once by the parser.

Inheritance diagram for Parde::Lowered::ComputeMultiWriteContainers:
[legend]

Public Member Functions

 ComputeMultiWriteContainers (const PhvInfo &ph, const CollectLoweredParserInfo &pi)
 

◆ Parde::Lowered::WarnTernaryMatchFields

class Parde::Lowered::WarnTernaryMatchFields

Issues warning for invalid container participating in ternary match.

If a container that participates in ternary match is invalid, model(HW) uses the last valid value in that container to perform the match. To help user avoid matching on stale value in container, we issue warning message so that user doesn't fall through this trapdoor.

Inheritance diagram for Parde::Lowered::WarnTernaryMatchFields:
[legend]

Public Member Functions

 WarnTernaryMatchFields (const PhvInfo &phv)
 
void end_apply () override
 
bool preorder (const IR::MAU::Table *tbl) override
 
- Public Member Functions inherited from P4::Inspector
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 void postorder (const IR::Node *)
 
virtual bool preorder (const IR::Node *)
 
virtual void revisit (const IR::Node *)
 
void revisit_visited ()
 
bool visit_in_progress (const IR::Node *n) 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 (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::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::Visitor
bool dontForwardChildrenBeforePreorder = false
 
bool joinFlows = false
 
bool visitDagOnce = true
 

Member Function Documentation

◆ end_apply()

void Parde::Lowered::WarnTernaryMatchFields::end_apply ( )
inlineoverridevirtual

Reimplemented from P4::Visitor.

◆ PragmaNoInit

class PragmaNoInit

Adds the no_init pragma to the specified fields with the specified gress.

Specifies that the indicated metadata field does not require initialization to 0 before its first use because the control plane guarantees that, in cases where this field's value is needed, it will always be written before it is read.

Inheritance diagram for PragmaNoInit:
[legend]

Public Member Functions

 PragmaNoInit (const PhvInfo &phv)
 
const ordered_set< const PHV::Field * > & getFields () const
 
- Public Member Functions inherited from P4::Inspector
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 void postorder (const IR::Node *)
 
virtual bool preorder (const IR::Node *)
 
virtual void revisit (const IR::Node *)
 
void revisit_visited ()
 
bool visit_in_progress (const IR::Node *n) 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
 

Static Public Attributes

static const char * description = "Specifies that the field does not require initialization."
 
static const char * help
 
static const char * name = "pa_no_init"
 BFN::Pragma interface.
 

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::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::Visitor
bool dontForwardChildrenBeforePreorder = false
 
bool joinFlows = false
 
bool visitDagOnce = true
 

Member Function Documentation

◆ getFields()

const ordered_set< const PHV::Field * > & PragmaNoInit::getFields ( ) const
inline
Returns
the set of fields fo which the pragma pa_no_init has been specified in the program

Member Data Documentation

◆ name

const char * PragmaNoInit::name = "pa_no_init"
static

BFN::Pragma interface.

Copyright (C) 2024 Intel Corporation

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

SPDX-License-Identifier: Apache-2.0