collect_strided_headers.h

 
#ifndef BF_P4C_PHV_COLLECT_STRIDED_HEADERS_H_
#define BF_P4C_PHV_COLLECT_STRIDED_HEADERS_H_
 
#include <map>
 
#include "backends/tofino/bf-p4c/phv/phv_fields.h"
#include "lib/cstring.h"
 
struct CollectStridedHeaders : public Inspector {
    PhvInfo &phv;
 
    std::map<cstring, std::vector<ordered_set<const PHV::Field *>>> stride_groups;
 
    explicit CollectStridedHeaders(PhvInfo &p) : phv(p) {}
 
    bool preorder(const IR::HeaderStack *hs) {
        auto state = findContext<IR::BFN::ParserState>();
 
        if (state && state->stride) {
            LOG4(state->name << " needs strided allocation (stride size = " << hs->size << ")");
 
            for (auto f : hs->type->fields) {
                ordered_set<const PHV::Field *> stride_group;
 
                for (int i = 0; i < hs->size; i++) {
                    cstring name = hs->name + "[" + cstring::to_cstring(i) + "]." + f->name;
                    auto field = phv.field(name);
                    stride_group.push_back(field);
                }
 
                stride_groups[hs->name].push_back(stride_group);
            }
        }
 
        return false;
    }
 
    const ordered_set<const PHV::Field *> *get_strided_group(const PHV::Field *f) const {
        for (auto &[_, groups] : stride_groups) {
            for (auto &group : groups) {
                if (group.count(f)) return &group;
            }
        }
 
        return nullptr;
    }
 
    profile_t init_apply(const IR::Node *root) override {
        profile_t rv = Inspector::init_apply(root);
        stride_groups.clear();
        return rv;
    }
};
 
#endif /* BF_P4C_PHV_COLLECT_STRIDED_HEADERS_H_ */