removeComplexExpressions.h

/*
Copyright 2013-present Barefoot Networks, 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 BACKENDS_COMMON_REMOVECOMPLEXEXPRESSIONS_H_
#define BACKENDS_COMMON_REMOVECOMPLEXEXPRESSIONS_H_
 
#include "frontends/common/resolveReferences/resolveReferences.h"
#include "frontends/p4/typeMap.h"
#include "ir/ir.h"
 
namespace P4 {
 
class RemoveComplexExpressionsPolicy {
 public:
    virtual ~RemoveComplexExpressionsPolicy() {}
    virtual bool convert(const IR::P4Control *control) const = 0;
};
 
class RemoveComplexExpressions : public Transform {
    P4::ReferenceMap *refMap;
    P4::TypeMap *typeMap;
    RemoveComplexExpressionsPolicy *policy;
    IR::IndexedVector<IR::Declaration> newDecls;
    IR::IndexedVector<IR::StatOrDecl> assignments;
 
    const IR::PathExpression *createTemporary(const IR::Expression *expression);
    const IR::Expression *simplifyExpression(const IR::Expression *expression, bool force);
    const IR::Vector<IR::Expression> *simplifyExpressions(const IR::Vector<IR::Expression> *vec,
                                                          bool force = false);
    const IR::Vector<IR::Argument> *simplifyExpressions(const IR::Vector<IR::Argument> *vec);
    const IR::IndexedVector<IR::NamedExpression> *simplifyExpressions(
        const IR::IndexedVector<IR::NamedExpression> *vec);
 
    const IR::Node *simpleStatement(IR::Statement *statement);
 
 public:
    RemoveComplexExpressions(P4::ReferenceMap *refMap, P4::TypeMap *typeMap,
                             RemoveComplexExpressionsPolicy *policy = nullptr)
        : refMap(refMap), typeMap(typeMap), policy(policy) {
        CHECK_NULL(refMap);
        CHECK_NULL(typeMap);
        setName("RemoveComplexExpressions");
    }
    const IR::Node *postorder(IR::SelectExpression *expression) override;
    const IR::Node *preorder(IR::ParserState *state) override {
        assignments.clear();
        return state;
    }
    const IR::Node *postorder(IR::ParserState *state) override {
        state->components.append(assignments);
        return state;
    }
    const IR::Node *postorder(IR::MethodCallExpression *expression) override;
    const IR::Node *preorder(IR::P4Parser *parser) override {
        newDecls.clear();
        return parser;
    }
    const IR::Node *postorder(IR::P4Parser *parser) override {
        if (newDecls.size() != 0) {
            // prepend declarations
            newDecls.append(parser->parserLocals);
            parser->parserLocals = newDecls;
        }
        return parser;
    }
    const IR::Node *preorder(IR::P4Control *control) override;
    const IR::Node *postorder(IR::P4Control *control) override {
        if (newDecls.size() != 0) {
            // prepend declarations
            newDecls.append(control->controlLocals);
            control->controlLocals = newDecls;
        }
        return control;
    }
    const IR::Node *postorder(IR::Statement *statement) override;
    const IR::Node *postorder(IR::MethodCallStatement *statement) override;
};
 
}  // namespace P4
 
#endif /* BACKENDS_COMMON_REMOVECOMPLEXEXPRESSIONS_H_ */