nestedStructs.h

/*
Copyright 2016 VMware, Inc.
 
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_NESTEDSTRUCTS_H_
#define MIDEND_NESTEDSTRUCTS_H_
 
#include "frontends/p4/typeChecking/typeChecker.h"
#include "ir/ir.h"
 
namespace P4 {
 
class ComplexValues final {
 public:
    struct Component : public IHasDbPrint {
        virtual const IR::Expression *convertToExpression() = 0;
        virtual Component *getComponent(cstring name) = 0;
        virtual void dbprint(std::ostream &out) const = 0;
    };
 
    struct FinalName : public Component {
        cstring newName;
        explicit FinalName(cstring name) : newName(name) {}
        const IR::Expression *convertToExpression() override {
            return new IR::PathExpression(IR::ID(newName));
        }
        Component *getComponent(cstring) override { return nullptr; }
        void dbprint(std::ostream &out) const override { out << newName << Log::endl; }
    };
 
    struct FieldsMap : public Component {
        ordered_map<cstring, Component *> members;
        const IR::Type *type;
        explicit FieldsMap(const IR::Type *type) : type(type) {
            CHECK_NULL(type);
            BUG_CHECK(type->is<IR::Type_Struct>(), "%1%: expected a struct", type);
        }
        const IR::Expression *convertToExpression() override {
            IR::IndexedVector<IR::NamedExpression> vec;
            for (auto m : members) {
                auto e = m.second->convertToExpression();
                vec.push_back(new IR::NamedExpression(m.first, e));
            }
            return new IR::StructExpression(type->getP4Type(), vec);
        }
        Component *getComponent(cstring name) override { return ::P4::get(members, name); }
        void dbprint(std::ostream &out) const override {
            out << Log::indent;
            for (auto m : members) out << m.first << "=>" << m.second;
            out << Log::unindent;
        }
    };
 
    std::map<const IR::Declaration_Variable *, Component *> values;
    std::map<const IR::Expression *, Component *> translation;
 
    ReferenceMap *refMap;
    TypeMap *typeMap;
 
    ComplexValues(ReferenceMap *refMap, TypeMap *typeMap) : refMap(refMap), typeMap(typeMap) {
        CHECK_NULL(refMap);
        CHECK_NULL(typeMap);
    }
    bool isNestedStruct(const IR::Type *type);
    template <class T>
    void explode(cstring prefix, const IR::Type_Struct *type, FieldsMap *map,
                 IR::Vector<T> *result);
    Component *getTranslation(const IR::IDeclaration *decl) {
        auto dv = decl->to<IR::Declaration_Variable>();
        if (dv == nullptr) return nullptr;
        return ::P4::get(values, dv);
    }
    Component *getTranslation(const IR::Expression *expression) {
        LOG2("Check translation " << dbp(expression));
        return ::P4::get(translation, expression);
    }
    void setTranslation(const IR::Expression *expression, Component *comp) {
        translation.emplace(expression, comp);
        LOG2("Translated " << dbp(expression) << " to " << comp);
    }
};

class RemoveNestedStructs final : public Transform {
    ComplexValues *values;
 
 public:
    explicit RemoveNestedStructs(ComplexValues *values) : values(values) {
        CHECK_NULL(values);
        setName("RemoveNestedStructs");
    }

    const IR::Node *postorder(IR::Declaration_Variable *decl) override;
    const IR::Node *postorder(IR::Member *expression) override;
    const IR::Node *postorder(IR::PathExpression *expression) override;
    const IR::Node *postorder(IR::MethodCallExpression *expression) override;
};
 
class NestedStructs final : public PassManager {
 public:
    NestedStructs(ReferenceMap *refMap, TypeMap *typeMap, TypeChecking *typeChecking = nullptr) {
        auto values = new ComplexValues(refMap, typeMap);
        if (!typeChecking) typeChecking = new TypeChecking(refMap, typeMap);
        passes.push_back(typeChecking);
        passes.push_back(new RemoveNestedStructs(values));
        passes.push_back(new ClearTypeMap(typeMap));
        setName("NestedStructs");
    }
};
 
}  // namespace P4
 
#endif /* MIDEND_NESTEDSTRUCTS_H_ */