P4C
The P4 Compiler
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#include <multiple_apply.h>
Public Member Functions | |
MultipleApply (const BFN_Options &options, std::optional< gress_t > gress=std::nullopt, bool dedup_only=false, bool run_default_next=true) | |
bool | default_next_error (cstring name) |
bool | mutex_error (cstring name) |
unsigned | num_default_next_errors () |
unsigned | num_mutex_errors () |
unsigned | num_topological_errors () |
bool | topological_error (cstring name) |
Public Member Functions inherited from P4::PassManager | |
PassManager (const PassManager &)=default | |
PassManager (const std::initializer_list< VisitorRef > &init) | |
PassManager (PassManager &&)=default | |
void | addDebugHook (DebugHook h, bool recursive=false) |
void | addDebugHooks (std::vector< DebugHook > hooks, bool recursive=false) |
void | addPasses (const std::initializer_list< VisitorRef > &init) |
const IR::Node * | apply_visitor (const IR::Node *, const char *=0) override |
bool | backtrack (trigger &trig) override |
PassManager * | clone () const override |
void | early_exit () |
void | listPasses (std::ostream &, cstring sep) const |
bool | never_backtracks () override |
void | removePasses (const std::vector< cstring > &exclude) |
void | setStopOnError (bool stop) |
Public Member Functions inherited from P4::Visitor | |
virtual bool | check_clone (const Visitor *a) |
virtual bool | check_global (cstring) |
virtual void | clear_globals () |
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 |
Public Member Functions inherited from P4::Backtrack |
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::PassManager | |
profile_t | init_apply (const IR::Node *root) override |
void | runDebugHooks (const char *visitorName, const IR::Node *node) |
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) |
virtual void | visitAgain () const |
virtual void | visitOnce () const |
Protected Attributes inherited from P4::PassManager | |
safe_vector< DebugHook > | debugHooks |
safe_vector< Visitor * > | passes |
bool | running = false |
unsigned | seqNo = 0 |
bool | stop_on_error = true |
Protected Attributes inherited from P4::Visitor | |
bool | dontForwardChildrenBeforePreorder = false |
bool | joinFlows = false |
bool | visitDagOnce = true |
The purpose of this set of passes is three-fold:
It checks the invariant that the conditional control flow that follows each table is the same across all calls of that table. This rules out the following program, in which the conditional behaviour on t2 depends on whether t1 hit or missed.
if (t1.apply().hit) { switch (t2.apply().action_run) { a1: { t3.apply(); } } } else { switch (t2.apply().action_run) { a1: { t4.apply(); } } }
It checks the invariant that the tables have a topological order, as they appear in the program text. This rules out the following program, in which t2 and t3 are applied in the opposite order in two branches of the program.
switch (t1.apply().action_run) { a1: { t2.apply(); t3.apply(); } a2: { t3.apply(); t2.apply(); } }
In principle, this invariant can be relaxed to say that the tables must form a DAG in the program dependence graph; i.e., the above program would be admissible if there are no data dependences between t2 and t3. This would require normalizing the order of tables, which we don't currently do. For now, we do the simpler, more restrictive thing, and can do the more relaxed thing in the future.