table_injected_deps.h

 
#ifndef BF_P4C_MAU_TABLE_INJECTED_DEPS_H_
#define BF_P4C_MAU_TABLE_INJECTED_DEPS_H_
 
#include <map>
#include <stack>
 
#include "backends/tofino/bf-p4c/common/field_defuse.h"
#include "backends/tofino/bf-p4c/ir/control_flow_visitor.h"
#include "backends/tofino/bf-p4c/mau/table_flow_graph.h"
#include "backends/tofino/bf-p4c/mau/table_mutex.h"
#include "backends/tofino/bf-p4c/mau/table_summary.h"
#include "backends/tofino/bf-p4c/phv/phv_fields.h"
#include "lib/ordered_map.h"
#include "lib/ordered_set.h"
#include "mau_visitor.h"
#include "table_dependency_graph.h"
 
using namespace P4;
 
class InjectControlDependencies : public MauInspector {
    bool preorder(const IR::MAU::TableSeq *seq) override;
 
 private:
    DependencyGraph &dg;
 
 public:
    explicit InjectControlDependencies(DependencyGraph &out) : dg(out) { visitDagOnce = false; }
};
 
class PredicationBasedControlEdges : public MauInspector {
    DependencyGraph *dg;
    const ControlPathwaysToTable &ctrl_paths;
    ordered_map<const IR::MAU::Table *, ordered_set<const IR::MAU::Table *>> edges_to_add;
 
 public:
    std::map<cstring, const IR::MAU::Table *> name_to_table;
 
    bool edge(const IR::MAU::Table *a, const IR::MAU::Table *b) const {
        if (edges_to_add.count(a) == 0) return false;
        return edges_to_add.at(a).count(b);
    }
 
    PredicationBasedControlEdges(DependencyGraph *d, const ControlPathwaysToTable &cp)
        : dg(d), ctrl_paths(cp) {}
 
 private:
    profile_t init_apply(const IR::Node *node) override {
        auto rv = MauInspector::init_apply(node);
        edges_to_add.clear();
        return rv;
    }
 
    void postorder(const IR::MAU::Table *tbl) override;
    void end_apply() override;
};

class AbstractDependencyInjector : public MauInspector {
 protected:
    bool tables_placed = false;
    DependencyGraph &dg;
    const ControlPathwaysToTable &ctrl_paths;
 
    Visitor::profile_t init_apply(const IR::Node *node) override {
        auto rv = MauInspector::init_apply(node);
        tables_placed = false;
        return rv;
    }
 
    bool preorder(const IR::MAU::Table *table) override {
        tables_placed |= table->is_placed();
        return true;
    }
 
 public:
    AbstractDependencyInjector(DependencyGraph &dg, const ControlPathwaysToTable &cp)
        : dg(dg), ctrl_paths(cp) {}
};

class InjectMetadataControlDependencies : public AbstractDependencyInjector {
    const PhvInfo &phv;
    const FlowGraph &fg;
    std::map<cstring, const IR::MAU::Table *> name_to_table;
 
    Visitor::profile_t init_apply(const IR::Node *node) override {
        auto rv = AbstractDependencyInjector::init_apply(node);
        name_to_table.clear();
        return rv;
    }
 
    bool preorder(const IR::MAU::Table *t) override {
        auto rv = AbstractDependencyInjector::preorder(t);
        name_to_table[t->name] = t;
        return rv;
    }
 
    void end_apply() override;
 
 public:
    InjectMetadataControlDependencies(const PhvInfo &p, DependencyGraph &g, const FlowGraph &f,
                                      const ControlPathwaysToTable &cp)
        : AbstractDependencyInjector(g, cp), phv(p), fg(f) {}
};
 
class InjectActionExitAntiDependencies : public AbstractDependencyInjector {
    const CalculateNextTableProp &cntp;
 
    void postorder(const IR::MAU::Table *table) override;
 
 public:
    InjectActionExitAntiDependencies(DependencyGraph &g, const CalculateNextTableProp &cntp,
                                     const ControlPathwaysToTable &cp)
        : AbstractDependencyInjector(g, cp), cntp(cntp) {}
};
 
class InjectControlExitDependencies : public AbstractDependencyInjector {
    std::map<gress_t, std::vector<const IR::MAU::Table *>> run_before_exit_tables;
 
    Visitor::profile_t init_apply(const IR::Node *node) override {
        LOG3("InjectControlExitDependencies begins");
        auto rv = AbstractDependencyInjector::init_apply(node);
        run_before_exit_tables.clear();
        return rv;
    }
 
    void end_apply(const IR::Node *node) override {
        Visitor::end_apply(node);
        link_run_before_exit_tables();
        LOG3("InjectControlExitDependencies ends");
    }
 
    bool preorder(const IR::MAU::Table *table) override;
    void postorder(const IR::MAU::Table *table) override;
 
    void collect_run_before_exit_table(const IR::MAU::Table *table);
    void inject_dependencies_from_gress_root_tables_to_first_rbe_table(
        const IR::MAU::Table *first_rbe_table);
    bool is_first_run_before_exit_table_in_gress(const IR::MAU::Table *rbe_table);
    const IR::MAU::TableSeq *get_gress_root_table_seq(const IR::MAU::Table *table);
    void link_run_before_exit_tables();
    void inject_control_exit_dependency(const IR::MAU::Table *source,
                                        const IR::MAU::Table *destination);
 
 public:
    InjectControlExitDependencies(DependencyGraph &dg, const ControlPathwaysToTable &cp)
        : AbstractDependencyInjector(dg, cp) {}
};
 
class InjectDarkAntiDependencies : public AbstractDependencyInjector {
    const PhvInfo &phv;
    bool placed = false;
    std::map<UniqueId, const IR::MAU::Table *> id_to_table;
 
    profile_t init_apply(const IR::Node *node) override {
        auto rv = AbstractDependencyInjector::init_apply(node);
        placed = false;
        id_to_table.clear();
        return rv;
    }
 
    bool preorder(const IR::MAU::Table *) override;
    void end_apply() override;
    // Get table corresponding to uid from id_to_table map
    // - handle case where @uid may not exists in id_to_table
    const IR::MAU::Table *getTable(UniqueId uid);
 
 public:
    InjectDarkAntiDependencies(const PhvInfo &p, DependencyGraph &g,
                               const ControlPathwaysToTable &cp)
        : AbstractDependencyInjector(g, cp), phv(p) {}
};
 
class TableFindInjectedDependencies : public PassManager {
    const PhvInfo &phv;
    DependencyGraph &dg;
    FlowGraph &fg;
    ControlPathwaysToTable ctrl_paths;
    CalculateNextTableProp cntp;
    const FieldDefUse *defuse;
    const TableSummary *summary;
 
    profile_t init_apply(const IR::Node *root) override {
        auto rv = PassManager::init_apply(root);
        fg.clear();
        return rv;
    }
 
 public:
    explicit TableFindInjectedDependencies(const PhvInfo &p, DependencyGraph &dg, FlowGraph &fg,
                                           const BFN_Options *options = nullptr,
                                           const TableSummary *summary = nullptr);
 
 private:
    // Duplicates to dominators
    ordered_map<const IR::MAU::TableSeq *, const IR::MAU::Table *> dominators;
};
 
// During alt-phv-alloc, the ALT_FINALIZE_TABLE round during table placement
// needs to have additional dependencies injected between overlayed fields which
// are disjoint. This ensures the tables are placed in the correct order to
// not violate read / write dependencies
class InjectDepForAltPhvAlloc : public MauInspector {
    const PhvInfo &phv;
    DependencyGraph &dg;
    const FieldDefUse &defuse;
    const TablesMutuallyExclusive &mutex;
 
    void end_apply() override;
 
 public:
    InjectDepForAltPhvAlloc(const PhvInfo &p, DependencyGraph &g, const FieldDefUse &du,
                            const TablesMutuallyExclusive &mu)
        : phv(p), dg(g), defuse(du), mutex(mu) {}
};
 
#endif /* BF_P4C_MAU_TABLE_INJECTED_DEPS_H_ */