pa_container_size.h

 
#ifndef BACKENDS_TOFINO_BF_P4C_PHV_PRAGMA_PA_CONTAINER_SIZE_H_
#define BACKENDS_TOFINO_BF_P4C_PHV_PRAGMA_PA_CONTAINER_SIZE_H_
 
#include <map>
#include <optional>
 
#include "backends/tofino/bf-p4c/phv/phv_fields.h"
#include "backends/tofino/bf-p4c/phv/utils/utils.h"
#include "ir/ir.h"
 
using namespace P4;
 
class PragmaContainerSize : public Inspector {
    // This pass may mutate field properties, e.g., add no_split on field.
    PhvInfo &phv_i;
    // alt-phv-alloc ONLY
    // this is a set of pa_container_size to fix problematic tables during alt-phv-alloc's table
    // replay stage.
    const ordered_map<cstring, std::vector<PHV::Size>> &container_size_constr;
    // pa_container_sizes_i pragmas collected from program.
    ordered_map<const PHV::Field *, std::vector<PHV::Size>> pa_container_sizes_i;
    // field_layouts_i is the expected container layout of the field. It is different
    // from the above raw pa_container_sizes, e.g. @pa_container_size("f1<32>", 8) will make
    // pa_container_sizes_i = {f1: [B]}
    // field_layouts_i = {f1: [8, 8, 8, 8]}.
    ordered_map<const PHV::Field *, std::vector<int>> field_layouts_i;
 
    profile_t init_apply(const IR::Node *root) override {
        profile_t rv = Inspector::init_apply(root);
        pa_container_sizes_i.clear();
        field_layouts_i.clear();
        return rv;
    }
 
    bool preorder(const IR::BFN::Pipe *pipe) override;
 
    void end_apply() override;
 
    // Add no-split constraint if the field has only one container size associated with it adn the
    // size of the container is larger than or equal to the size of the field. The pragma also
    // implies that the entire field must be packed into a single specified size container.
    void check_and_add_no_split(PHV::Field *field) const;
 
 public:
    PragmaContainerSize(PhvInfo &phv,
                        const ordered_map<cstring, std::vector<PHV::Size>> &container_size_constr)
        : phv_i(phv), container_size_constr(container_size_constr) {}
    explicit PragmaContainerSize(PhvInfo &phv)
        : phv_i(phv), container_size_constr(*(new ordered_map<cstring, std::vector<PHV::Size>>)) {}
 
    static const char *name;
    static const char *description;
    static const char *help;
 
    const ordered_map<const PHV::Field *, std::vector<PHV::Size>> &field_to_sizes() const {
        return pa_container_sizes_i;
    }
 
    // field_to_layout return the container layout of the field.
    // e.g.
    // "f1" => [8,8,8,8], @pa_container_size("f1<32>", 8)
    // "f2" => [8,16], @pa_container_size("f2<16>", 8, 16).
    const ordered_map<const PHV::Field *, std::vector<int>> &field_to_layout() const {
        return field_layouts_i;
    }
 
    // expected_container_size returns the expected container size for this fs.
    // if not specified, return std::nullopt, and
    // if @p fs spans over more than one container, return PHV::Size::null
    std::optional<PHV::Size> expected_container_size(const PHV::FieldSlice &fs) const;
 
    bool is_specified(const PHV::Field *field) const { return pa_container_sizes_i.count(field); }
 
    void add_constraint(const PHV::Field *field, std::vector<PHV::Size> sizes);
 
    cstring printSizeConstraints(const std::vector<PHV::Size> &sizes) const;
 
    bool check_and_add_constraint(const PHV::Field *field, std::vector<PHV::Size> sizes);
};
 
std::ostream &operator<<(std::ostream &out, const PragmaContainerSize &pa_cs);
 
#endif /* BACKENDS_TOFINO_BF_P4C_PHV_PRAGMA_PA_CONTAINER_SIZE_H_ */