flattenHeaders.h

/*
    Copyright 2018 MNK Consulting, LLC.
    http://mnkcg.com
 
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.
*/
 
#ifndef MIDEND_FLATTENHEADERS_H_
#define MIDEND_FLATTENHEADERS_H_
 
#include "flattenInterfaceStructs.h"
#include "frontends/p4/typeChecking/typeChecker.h"
#include "ir/ir.h"
 
namespace P4 {

class FindHeaderTypesToReplace : public Inspector {
    P4::TypeMap *typeMap;
    AnnotationSelectionPolicy *policy;
    ordered_map<cstring, StructTypeReplacement<IR::Type_StructLike> *> replacement;
 
 public:
    explicit FindHeaderTypesToReplace(P4::TypeMap *typeMap, AnnotationSelectionPolicy *policy)
        : typeMap(typeMap), policy(policy) {
        setName("FindHeaderTypesToReplace");
        CHECK_NULL(typeMap);
    }
    bool preorder(const IR::Type_Header *type) override;
    void createReplacement(const IR::Type_Header *type, AnnotationSelectionPolicy *policy);
    StructTypeReplacement<IR::Type_StructLike> *getReplacement(const cstring name) const {
        return ::P4::get(replacement, name);
    }
    bool empty() const { return replacement.empty(); }
};

class ReplaceHeaders : public Transform, P4WriteContext {
    P4::TypeMap *typeMap;
    FindHeaderTypesToReplace *findHeaderTypesToReplace;
 
 public:
    explicit ReplaceHeaders(P4::TypeMap *typeMap,
                            FindHeaderTypesToReplace *findHeaderTypesToReplace)
        : typeMap(typeMap), findHeaderTypesToReplace(findHeaderTypesToReplace) {
        CHECK_NULL(typeMap);
        CHECK_NULL(findHeaderTypesToReplace);
        setName("ReplaceHeaders");
    }
 
    const IR::Node *preorder(IR::P4Program *program) override;
    const IR::Node *postorder(IR::Member *expression) override;
    const IR::Node *postorder(IR::Type_Header *type) override;
};
 
class FlattenHeaders final : public PassManager {
 public:
    FlattenHeaders(TypeMap *typeMap, AnnotationSelectionPolicy *policy = nullptr) {
        auto findHeadersToReplace = new FindHeaderTypesToReplace(typeMap, policy);
        passes.push_back(new TypeChecking(nullptr, typeMap));
        passes.push_back(findHeadersToReplace);
        passes.push_back(new ReplaceHeaders(typeMap, findHeadersToReplace));
        passes.push_back(new ClearTypeMap(typeMap));
        setName("FlattenHeaders");
    }
};
 
}  // namespace P4
 
#endif /* MIDEND_FLATTENHEADERS_H_ */