CallDAG.cpp

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Author : Olli Etuaho
Date : 2016-12-16 12:01:18
Hash : 77ba408a
Message : Unify Diagnostics interface Use the same kind of interface for reporting preprocessor errors as for reporting regular compiler errors, and make global errors like having too many uniforms also go through Diagnostics. Also don't create std::string objects unnecessarily. Includes cleanups of some dead code related to reporting errors. BUG=angleproject:1670 TEST=angle_unittests Change-Id: I3ee794d32ddeec1826bdf1b76b558f35259f82c0 Reviewed-on: https://chromium-review.googlesource.com/421527 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
src/compiler/translator/CallDAG.cpp
//
// Copyright (c) 2002-2015 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// CallDAG.h: Implements a call graph DAG of functions to be re-used accross
// analyses, allows to efficiently traverse the functions in topological
// order.

#include "compiler/translator/CallDAG.h"
#include "compiler/translator/Diagnostics.h"

namespace sh
{

// The CallDAGCreator does all the processing required to create the CallDAG
// structure so that the latter contains only the necessary variables.
class CallDAG::CallDAGCreator : public TIntermTraverser
{
  public:
    CallDAGCreator(TDiagnostics *diagnostics)
        : TIntermTraverser(true, false, true),
          mDiagnostics(diagnostics),
          mCurrentFunction(nullptr),
          mCurrentIndex(0)
    {
    }

    InitResult assignIndices()
    {
        int skipped = 0;
        for (auto &it : mFunctions)
        {
            // Skip unimplemented functions
            if (it.second.node)
            {
                InitResult result = assignIndicesInternal(&it.second);
                if (result != INITDAG_SUCCESS)
                {
                    return result;
                }
            }
            else
            {
                skipped++;
            }
        }

        ASSERT(mFunctions.size() == mCurrentIndex + skipped);
        return INITDAG_SUCCESS;
    }

    void fillDataStructures(std::vector<Record> *records, std::map<int, int> *idToIndex)
    {
        ASSERT(records->empty());
        ASSERT(idToIndex->empty());

        records->resize(mCurrentIndex);

        for (auto &it : mFunctions)
        {
            CreatorFunctionData &data = it.second;
            // Skip unimplemented functions
            if (!data.node)
            {
                continue;
            }
            ASSERT(data.index < records->size());
            Record &record = (*records)[data.index];

            record.name = data.name.data();
            record.node = data.node;

            record.callees.reserve(data.callees.size());
            for (auto &callee : data.callees)
            {
                record.callees.push_back(static_cast<int>(callee->index));
            }

            (*idToIndex)[data.node->getFunctionSymbolInfo()->getId()] =
                static_cast<int>(data.index);
        }
    }

  private:
    struct CreatorFunctionData
    {
        CreatorFunctionData() : node(nullptr), index(0), indexAssigned(false), visiting(false) {}

        std::set<CreatorFunctionData *> callees;
        TIntermFunctionDefinition *node;
        TString name;
        size_t index;
        bool indexAssigned;
        bool visiting;
    };

    bool visitFunctionDefinition(Visit visit, TIntermFunctionDefinition *node) override
    {
        // Create the record if need be and remember the node.
        if (visit == PreVisit)
        {
            auto it = mFunctions.find(node->getFunctionSymbolInfo()->getName());

            if (it == mFunctions.end())
            {
                mCurrentFunction = &mFunctions[node->getFunctionSymbolInfo()->getName()];
            }
            else
            {
                mCurrentFunction = &it->second;
            }

            mCurrentFunction->node = node;
            mCurrentFunction->name = node->getFunctionSymbolInfo()->getName();
        }
        else if (visit == PostVisit)
        {
            mCurrentFunction = nullptr;
        }
        return true;
    }

    // Aggregates the AST node for each function as well as the name of the functions called by it
    bool visitAggregate(Visit visit, TIntermAggregate *node) override
    {
        switch (node->getOp())
        {
            case EOpPrototype:
                if (visit == PreVisit)
                {
                    // Function declaration, create an empty record.
                    auto &record = mFunctions[node->getFunctionSymbolInfo()->getName()];
                    record.name  = node->getFunctionSymbolInfo()->getName();
                }
                break;
            case EOpFunctionCall:
            {
                // Function call, add the callees
                if (visit == PreVisit)
                {
                    // Do not handle calls to builtin functions
                    if (node->isUserDefined())
                    {
                        auto it = mFunctions.find(node->getFunctionSymbolInfo()->getName());
                        ASSERT(it != mFunctions.end());

                        // We might be in a top-level function call to set a global variable
                        if (mCurrentFunction)
                        {
                            mCurrentFunction->callees.insert(&it->second);
                        }
                    }
                }
                break;
            }
            default:
                break;
        }
        return true;
    }

    // Recursively assigns indices to a sub DAG
    InitResult assignIndicesInternal(CreatorFunctionData *root)
    {
        // Iterative implementation of the index assignment algorithm. A recursive version
        // would be prettier but since the CallDAG creation runs before the limiting of the
        // call depth, we might get stack overflows (computation of the call depth uses the
        // CallDAG).

        ASSERT(root);

        if (root->indexAssigned)
        {
            return INITDAG_SUCCESS;
        }

        // If we didn't have to detect recursion, functionsToProcess could be a simple queue
        // in which we add the function being processed's callees. However in order to detect
        // recursion we need to know which functions we are currently visiting. For that reason
        // functionsToProcess will look like a concatenation of segments of the form
        // [F visiting = true, subset of F callees with visiting = false] and the following
        // segment (if any) will be start with a callee of F.
        // This way we can remember when we started visiting a function, to put visiting back
        // to false.
        TVector<CreatorFunctionData *> functionsToProcess;
        functionsToProcess.push_back(root);

        InitResult result = INITDAG_SUCCESS;

        std::stringstream errorStream;

        while (!functionsToProcess.empty())
        {
            CreatorFunctionData *function = functionsToProcess.back();

            if (function->visiting)
            {
                function->visiting      = false;
                function->index         = mCurrentIndex++;
                function->indexAssigned = true;

                functionsToProcess.pop_back();
                continue;
            }

            if (!function->node)
            {
                errorStream << "Undefined function '" << function->name
                            << ")' used in the following call chain:";
                result = INITDAG_UNDEFINED;
                break;
            }

            if (function->indexAssigned)
            {
                functionsToProcess.pop_back();
                continue;
            }

            function->visiting = true;

            for (auto callee : function->callees)
            {
                functionsToProcess.push_back(callee);

                // Check if the callee is already being visited after pushing it so that it appears
                // in the chain printed in the info log.
                if (callee->visiting)
                {
                    errorStream << "Recursive function call in the following call chain:";
                    result = INITDAG_RECURSION;
                    break;
                }
            }

            if (result != INITDAG_SUCCESS)
            {
                break;
            }
        }

        // The call chain is made of the function we were visiting when the error was detected.
        if (result != INITDAG_SUCCESS)
        {
            bool first = true;
            for (auto function : functionsToProcess)
            {
                if (function->visiting)
                {
                    if (!first)
                    {
                        errorStream << " -> ";
                    }
                    errorStream << function->name << ")";
                    first = false;
                }
            }
            if (mDiagnostics)
            {
                std::string errorStr = errorStream.str();
                mDiagnostics->globalError(errorStr.c_str());
            }
        }

        return result;
    }

    TDiagnostics *mDiagnostics;

    std::map<TString, CreatorFunctionData> mFunctions;
    CreatorFunctionData *mCurrentFunction;
    size_t mCurrentIndex;
};

// CallDAG

CallDAG::CallDAG()
{
}

CallDAG::~CallDAG()
{
}

const size_t CallDAG::InvalidIndex = std::numeric_limits<size_t>::max();

size_t CallDAG::findIndex(const TFunctionSymbolInfo *functionInfo) const
{
    auto it = mFunctionIdToIndex.find(functionInfo->getId());

    if (it == mFunctionIdToIndex.end())
    {
        return InvalidIndex;
    }
    else
    {
        return it->second;
    }
}

const CallDAG::Record &CallDAG::getRecordFromIndex(size_t index) const
{
    ASSERT(index != InvalidIndex && index < mRecords.size());
    return mRecords[index];
}

const CallDAG::Record &CallDAG::getRecord(const TIntermAggregate *function) const
{
    size_t index = findIndex(function->getFunctionSymbolInfo());
    ASSERT(index != InvalidIndex && index < mRecords.size());
    return mRecords[index];
}

size_t CallDAG::size() const
{
    return mRecords.size();
}

void CallDAG::clear()
{
    mRecords.clear();
    mFunctionIdToIndex.clear();
}

CallDAG::InitResult CallDAG::init(TIntermNode *root, TDiagnostics *diagnostics)
{
    CallDAGCreator creator(diagnostics);

    // Creates the mapping of functions to callees
    root->traverse(&creator);

    // Does the topological sort and detects recursions
    InitResult result = creator.assignIndices();
    if (result != INITDAG_SUCCESS)
    {
        return result;
    }

    creator.fillDataStructures(&mRecords, &mFunctionIdToIndex);
    return INITDAG_SUCCESS;
}

}  // namespace sh
kc3-lang/angle/src/compiler/translator/CallDAG.cpp

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kc3-lang/angle /src/compiler/translator/CallDAG.cpp
