functionsInlining.h

/*
Copyright 2018 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_FUNCTIONSINLINING_H_
#define FRONTENDS_P4_FUNCTIONSINLINING_H_
 
#include "commonInlining.h"
#include "frontends/common/resolveReferences/referenceMap.h"
#include "frontends/common/resolveReferences/resolveReferences.h"
#include "frontends/p4/typeChecking/typeChecker.h"
#include "frontends/p4/unusedDeclarations.h"
#include "ir/ir.h"
 
namespace P4 {
using FunctionCallInfo = SimpleCallInfo<IR::Node, IR::Statement>;
using FunctionsInlineWorkList = SimpleInlineWorkList<FunctionCallInfo>;
using FunctionsInlineList = SimpleInlineList<IR::Node, FunctionCallInfo, FunctionsInlineWorkList>;
 
class DiscoverFunctionsInlining : public Inspector, public ResolutionContext {
    FunctionsInlineList *toInline;  // output
    P4::TypeMap *typeMap;           // input
 
 public:
    DiscoverFunctionsInlining(FunctionsInlineList *toInline, P4::TypeMap *typeMap)
        : toInline(toInline), typeMap(typeMap) {
        CHECK_NULL(toInline);
        CHECK_NULL(typeMap);
        setName("DiscoverFunctionsInlining");
    }
    Visitor::profile_t init_apply(const IR::Node *node) override;
    void postorder(const IR::MethodCallExpression *mce) override;
};

class FunctionsInliner : public AbstractInliner<FunctionsInlineList, FunctionsInlineWorkList> {
    std::unique_ptr<MinimalNameGenerator> nameGen;
 
    // All elements in the replacement map are actually IR::Function objects
    using ReplacementMap = FunctionsInlineWorkList::ReplacementMap;
    std::vector<ReplacementMap *> replacementStack;
    std::unordered_map<const IR::MethodCallExpression *, const IR::Expression *>
        pendingReplacements;

    const IR::Expression *cloneBody(const IR::IndexedVector<IR::StatOrDecl> &src,
                                    IR::IndexedVector<IR::StatOrDecl> &dest);
    const IR::Statement *inlineBefore(const IR::Node *calleeNode,
                                      const IR::MethodCallExpression *call,
                                      const IR::Statement *before);
    bool preCaller();
    const IR::Node *postCaller(const IR::Node *caller);
    const ReplacementMap *getReplacementMap() const;
    void dumpReplacementMap() const;
    class isLocalExpression;  // functor to test actual arguments scope use
 
 public:
    FunctionsInliner() = default;
    Visitor::profile_t init_apply(const IR::Node *node) override;
    void end_apply(const IR::Node *node) override;
    const IR::Node *preorder(IR::Function *function) override;
    const IR::Node *preorder(IR::P4Control *control) override;
    const IR::Node *preorder(IR::P4Parser *parser) override;
    const IR::Node *preorder(IR::P4Action *action) override;
    const IR::Node *preorder(IR::MethodCallStatement *statement) override;
    const IR::Node *preorder(IR::MethodCallExpression *expr) override;
    const IR::Node *preorder(IR::AssignmentStatement *statement) override;
    const IR::Node *preorder(IR::IfStatement *statement) override;
};
 
typedef InlineDriver<FunctionsInlineList, FunctionsInlineWorkList> InlineFunctionsDriver;

class CloneVariableDeclarations : public Transform {
 public:
    CloneVariableDeclarations() {
        setName("CloneVariableDeclarations");
        visitDagOnce = false;
    }
    const IR::Node *postorder(IR::Declaration_Variable *declaration) override {
        // this will have a different declid
        auto result = new IR::Declaration_Variable(declaration->srcInfo, declaration->getName(),
                                                   declaration->annotations, declaration->type,
                                                   declaration->initializer);
        LOG3("Cloned " << dbp(result));
        return result;
    }
};
 
class InlineFunctions : public PassManager {
    FunctionsInlineList functionsToInline;
 
 public:
    InlineFunctions(TypeMap *typeMap, const RemoveUnusedPolicy &policy) {
        passes.push_back(
            new PassRepeated({new TypeChecking(nullptr, typeMap),
                              new DiscoverFunctionsInlining(&functionsToInline, typeMap),
                              new InlineFunctionsDriver(&functionsToInline, new FunctionsInliner()),
                              new RemoveAllUnusedDeclarations(policy)}));
        passes.push_back(new CloneVariableDeclarations());
        setName("InlineFunctions");
    }
};
 
}  // namespace P4
 
#endif /* FRONTENDS_P4_FUNCTIONSINLINING_H_ */