specializeGenericFunctions.h

/*
Copyright 2020 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_SPECIALIZEGENERICFUNCTIONS_H_
#define FRONTENDS_P4_SPECIALIZEGENERICFUNCTIONS_H_
 
#include "frontends/common/resolveReferences/referenceMap.h"
#include "frontends/common/resolveReferences/resolveReferences.h"
#include "frontends/p4/typeChecking/typeChecker.h"
#include "ir/ir.h"
 
namespace P4 {
 
struct FunctionSpecialization {
    cstring name;
    const IR::Function *original;
    const IR::Function *specialized;
    const IR::MethodCallExpression *invocation;
    const IR::Node *insertBefore;
 
    FunctionSpecialization(cstring name, const IR::MethodCallExpression *invocation,
                           const IR::Function *function, const IR::Node *insert)
        : name(name),
          original(function),
          specialized(nullptr),
          invocation(invocation),
          insertBefore(insert) {
        CHECK_NULL(invocation);
        CHECK_NULL(invocation);
        CHECK_NULL(insertBefore);
    }
};
 
struct FunctionSpecializationMap {
    TypeMap *typeMap;
    ordered_map<const IR::MethodCallExpression *, FunctionSpecialization *> map;
    // Keep track of the values in the above map which are already
    // inserted in the program.
    std::set<FunctionSpecialization *> inserted;
 
    void add(const IR::MethodCallExpression *mce, const IR::Function *func, const IR::Node *insert,
             NameGenerator *nameGen) {
        cstring name = nameGen->newName(func->name.string_view());
        map.emplace(mce, new FunctionSpecialization(name, mce, func, insert));
    }
    FunctionSpecialization *get(const IR::MethodCallExpression *mce) const {
        return ::P4::get(map, mce);
    }
    IR::Vector<IR::Node> *getInsertions(const IR::Node *insertionPoint) {
        IR::Vector<IR::Node> *result = nullptr;
        for (auto s : map) {
            if (inserted.find(s.second) != inserted.end()) continue;
            if (s.second->insertBefore == insertionPoint) {
                if (result == nullptr) result = new IR::Vector<IR::Node>();
                LOG2("Will insert " << dbp(s.second->specialized) << " before "
                                    << dbp(insertionPoint));
                result->push_back(s.second->specialized);
                inserted.emplace(s.second);
            }
        }
        return result;
    }
};
 
class FindFunctionSpecializations : public Inspector, public ResolutionContext {
    FunctionSpecializationMap *specMap;
    MinimalNameGenerator nameGen;
 
 public:
    explicit FindFunctionSpecializations(FunctionSpecializationMap *specMap) : specMap(specMap) {
        CHECK_NULL(specMap);
        setName("FindFunctionSpecializations");
    }
 
    bool preorder(const IR::MethodCallExpression *call) override;
    profile_t init_apply(const IR::Node *node) override;
};
 
class SpecializeFunctions : public Transform {
    FunctionSpecializationMap *specMap;
 
 public:
    explicit SpecializeFunctions(FunctionSpecializationMap *specMap) : specMap(specMap) {
        CHECK_NULL(specMap);
        setName("SpecializeFunctions");
    }
    const IR::Node *postorder(IR::Function *function) override;
    const IR::Node *postorder(IR::MethodCallExpression *) override;
    const IR::Node *insert(const IR::Node *before);
    const IR::Node *preorder(IR::P4Control *control) override { return insert(control); }
    const IR::Node *preorder(IR::P4Parser *parser) override { return insert(parser); }
    const IR::Node *preorder(IR::Function *function) override { return insert(function); }
};
 
class SpecializeGenericFunctions : public PassManager {
    FunctionSpecializationMap specMap;
 
 public:
    explicit SpecializeGenericFunctions(TypeMap *typeMap) {
        passes.emplace_back(new TypeChecking(nullptr, typeMap));
        passes.emplace_back(new FindFunctionSpecializations(&specMap));
        passes.emplace_back(new SpecializeFunctions(&specMap));
        specMap.typeMap = typeMap;
        setName("SpecializeGenericFunctions");
    }
};
 
}  // namespace P4
 
#endif /* FRONTENDS_P4_SPECIALIZEGENERICFUNCTIONS_H_ */