parserControlFlow.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 FRONTENDS_P4_PARSERCONTROLFLOW_H_
#define FRONTENDS_P4_PARSERCONTROLFLOW_H_
 
#include "frontends/p4/moveDeclarations.h"
#include "frontends/p4/simplify.h"
#include "frontends/p4/uniqueNames.h"
#include "ir/ir.h"
 
namespace P4 {
 
class DoRemoveParserControlFlow : public Transform {
    MinimalNameGenerator nameGen;
 
 public:
    DoRemoveParserControlFlow() { setName("DoRemoveParserControlFlow"); }
    const IR::Node *postorder(IR::ParserState *state) override;
    Visitor::profile_t init_apply(const IR::Node *node) override;
};
 
class RemoveParserControlFlow : public PassRepeated {
 public:
    explicit RemoveParserControlFlow(TypeMap *typeMap) : PassRepeated({}) {
        passes.emplace_back(new DoRemoveParserControlFlow());
        passes.emplace_back(new SimplifyControlFlow(typeMap));
        setName("RemoveParserControlFlow");
    }
};
 
class IfInParser : public Inspector {
    bool *found;
 
 public:
    explicit IfInParser(bool *found) : found(found) {
        CHECK_NULL(found);
        setName("IfInParser");
    }
    void postorder(const IR::IfStatement *) override {
        if (findContext<IR::P4Parser>()) *found = true;
    }
};
 
class RemoveParserIfs : public PassManager {
    bool found = false;
 
 public:
    explicit RemoveParserIfs(TypeMap *typeMap) {
        passes.push_back(new IfInParser(&found));
        passes.push_back(
            new PassIf([this] { return found; },
                       {                    // only do this if we found an 'if' in a parser
                        new UniqueNames(),  // Give each local declaration a unique internal name
                        new MoveDeclarations(true),  // Move all local declarations to the beginning
                        new RemoveParserControlFlow(typeMap)}));
    }
};
 
}  // namespace P4
 
#endif /* FRONTENDS_P4_PARSERCONTROLFLOW_H_ */