evaluator.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 EVALUATOR_EVALUATOR_H_
#define EVALUATOR_EVALUATOR_H_
 
#include "frontends/common/resolveReferences/resolveReferences.h"
#include "frontends/p4/typeMap.h"
#include "ir/ir.h"
#include "ir/pass_manager.h"
 
namespace P4 {
 
class IHasBlock {
 public:
    virtual IR::ToplevelBlock *getToplevelBlock() const = 0;
};
 
class Evaluator final : public Inspector, public IHasBlock {
    const ReferenceMap *refMap;
    const TypeMap *typeMap;
    std::vector<IR::Block *> blockStack;
    IR::ToplevelBlock *toplevelBlock;
 
 protected:
    void pushBlock(IR::Block *block);
    void popBlock(IR::Block *block);
 
 public:
    Evaluator(const ReferenceMap *refMap, const TypeMap *typeMap)
        : refMap(refMap), typeMap(typeMap), toplevelBlock(nullptr) {
        CHECK_NULL(refMap);
        CHECK_NULL(typeMap);
        setName("Evaluator");
        visitDagOnce = false;
    }
    IR::ToplevelBlock *getToplevelBlock() const override { return toplevelBlock; }
 
    IR::Block *currentBlock() const;
    void setValue(const IR::Node *node, const IR::CompileTimeValue *constant);
    bool hasValue(const IR::Node *node) const;
    const IR::CompileTimeValue *getValue(const IR::Node *node) const;

    std::vector<const IR::CompileTimeValue *> *evaluateArguments(
        const IR::ParameterList *parameters, const IR::Vector<IR::Argument> *arguments,
        IR::Block *context);
 
    profile_t init_apply(const IR::Node *node) override;
 
    // The traversal order is controlled very explicitly
    bool preorder(const IR::P4Program *program) override;
    bool preorder(const IR::Declaration_Constant *decl) override;
    bool preorder(const IR::P4Table *table) override;
    bool preorder(const IR::Declaration_Instance *inst) override;
    bool preorder(const IR::ConstructorCallExpression *inst) override;
    bool preorder(const IR::MethodCallExpression *expr) override;
    bool preorder(const IR::PathExpression *expression) override;
    bool preorder(const IR::Property *prop) override;
    bool preorder(const IR::Member *expression) override;
    bool preorder(const IR::ListExpression *expression) override;
    bool preorder(const IR::P4ListExpression *expression) override;
    bool preorder(const IR::StructExpression *expression) override;
    bool preorder(const IR::Constant *expression) override {
        setValue(expression, expression);
        return false;
    }
    bool preorder(const IR::StringLiteral *expression) override {
        setValue(expression, expression);
        return false;
    }
    bool preorder(const IR::BoolLiteral *expression) override {
        setValue(expression, expression);
        return false;
    }
    bool preorder(const IR::ListCompileTimeValue *expression) override {
        setValue(expression, expression);
        return false;
    }
    bool preorder(const IR::StructCompileTimeValue *expression) override {
        setValue(expression, expression);
        return false;
    }
    bool preorder(const IR::Declaration_ID *expression) override {
        setValue(expression, expression);
        return false;
    }
 
    const IR::Block *processConstructor(const IR::Node *node, const IR::Type *type,
                                        const IR::Type *instanceType,
                                        const IR::Vector<IR::Argument> *arguments);
};

class EvaluatorPass final : public PassManager, public IHasBlock {
    P4::Evaluator *evaluator;
 
 public:
    IR::ToplevelBlock *getToplevelBlock() const override { return evaluator->getToplevelBlock(); }
    EvaluatorPass(ReferenceMap *refMap, TypeMap *typeMap);
};
 
}  // namespace P4
 
#endif /* EVALUATOR_EVALUATOR_H_ */