bmv2/common/backend.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_BMV2_COMMON_BACKEND_H_
#define BACKENDS_BMV2_COMMON_BACKEND_H_
 
#include "JsonObjects.h"
#include "controlFlowGraph.h"
#include "expression.h"
#include "frontends/common/model.h"
#include "frontends/p4/coreLibrary.h"
#include "helpers.h"
#include "ir/ir.h"
#include "lib/cstring.h"
#include "lib/error.h"
#include "lib/exceptions.h"
#include "lib/gc.h"
#include "lib/json.h"
#include "lib/log.h"
#include "lib/nullstream.h"
#include "midend/actionSynthesis.h"
#include "midend/convertEnums.h"
#include "midend/removeComplexExpressions.h"
#include "midend/removeLeftSlices.h"
#include "options.h"
#include "sharedActionSelectorCheck.h"
 
namespace P4::BMV2 {
 
enum gress_t { INGRESS, EGRESS };
enum block_t {
    PARSER,
    PIPELINE,
    DEPARSER,
    V1_PARSER,
    V1_DEPARSER,
    V1_INGRESS,
    V1_EGRESS,
    V1_VERIFY,
    V1_COMPUTE
};
 
class ExpressionConverter;

class Backend {
 public:
    BMV2Options &options;
    P4::ReferenceMap *refMap;
    P4::TypeMap *typeMap;
    P4::ConvertEnums::EnumMapping *enumMap;
    P4::P4CoreLibrary &corelib;
    BMV2::JsonObjects *json;
    const IR::ToplevelBlock *toplevel = nullptr;
 
 public:
    Backend(BMV2Options &options, P4::ReferenceMap *refMap, P4::TypeMap *typeMap,
            P4::ConvertEnums::EnumMapping *enumMap)
        : options(options),
          refMap(refMap),
          typeMap(typeMap),
          enumMap(enumMap),
          corelib(P4::P4CoreLibrary::instance()),
          json(new BMV2::JsonObjects()) {
        refMap->setIsV1(options.isv1());
    }
    void serialize(std::ostream &out) const { json->toplevel->serialize(out); }
    virtual void convert(const IR::ToplevelBlock *block) = 0;
};

// The policy is: do not synthesize actions for the controls whose names
class SkipControls : public P4::ActionSynthesisPolicy {
    const std::set<cstring> *skip;
 
 public:
    explicit SkipControls(const std::set<cstring> *skip) : skip(skip) { CHECK_NULL(skip); }
    bool convert(const Visitor::Context *, const IR::P4Control *control) override {
        if (skip->find(control->name) != skip->end()) return false;
        return true;
    }
};

class ProcessControls : public P4::RemoveComplexExpressionsPolicy {
    const std::set<cstring> *process;
 
 public:
    explicit ProcessControls(const std::set<cstring> *process) : process(process) {
        CHECK_NULL(process);
    }
    bool convert(const IR::P4Control *control) const {
        if (process->find(control->name) != process->end()) return true;
        return false;
    }
};

class RenameUserMetadata : public Transform {
    P4::ReferenceMap *refMap;
    const IR::Type_Struct *userMetaType;
    cstring namePrefix;
    bool renamed = false;
 
 public:
    RenameUserMetadata(P4::ReferenceMap *refMap, const IR::Type_Struct *userMetaType,
                       cstring namePrefix)
        : refMap(refMap), userMetaType(userMetaType), namePrefix(namePrefix) {
        setName("RenameUserMetadata");
        CHECK_NULL(refMap);
        visitDagOnce = false;
    }
 
    const IR::Node *postorder(IR::Type_Struct *type) override {
        // Clone the user metadata type
        auto orig = getOriginal<IR::Type_Struct>();
        if (userMetaType->name != orig->name) return type;
 
        auto vec = new IR::IndexedVector<IR::Node>();
        LOG2("Creating clone of " << orig);
        renamed = true;
        auto clone = type->clone();
        clone->name = namePrefix;
        vec->push_back(clone);
 
        // Rename all fields
        IR::IndexedVector<IR::StructField> fields;
        for (auto f : type->fields) {
            auto anno = f->getAnnotation(IR::Annotation::nameAnnotation);
            cstring suffix = cstring::empty;
            if (anno != nullptr) suffix = anno->getName();
            if (suffix.startsWith(".")) {
                // We can't change the name of this field.
                // Hopefully the user knows what they are doing.
                fields.push_back(f->clone());
                continue;
            }
 
            if (!suffix.isNullOrEmpty())
                suffix = "."_cs + suffix;
            else
                suffix = "."_cs + f->name;
            cstring newName = namePrefix + suffix;
            auto stringLit = new IR::StringLiteral(newName);
            LOG2("Renaming " << f << " to " << newName);
            auto annos = f->annotations->addOrReplace(IR::Annotation::nameAnnotation, stringLit);
            auto field = new IR::StructField(f->srcInfo, f->name, annos, f->type);
            fields.push_back(field);
        }
 
        auto annotated =
            new IR::Type_Struct(type->srcInfo, type->name, type->annotations, std::move(fields));
        vec->push_back(annotated);
        return vec;
    }
 
    const IR::Node *preorder(IR::Type_Name *type) override {
        // Find any reference to the user metadata type that is used and replace them
        auto decl = refMap->getDeclaration(type->path);
        if (decl == userMetaType)
            type->path = new IR::Path(type->path->srcInfo, IR::ID(type->path->srcInfo, namePrefix));
        LOG2("Replacing reference with " << type);
        return type;
    }
 
    void end_apply(const IR::Node *) override {
        BUG_CHECK(renamed, "Could not identify user metadata type declaration %1%", userMetaType);
    }
};
 
}  // namespace P4::BMV2
 
#endif /* BACKENDS_BMV2_COMMON_BACKEND_H_ */