path: root/libsolidity/interface/CompilerStack.cpp

/*
    This file is part of solidity.

    solidity is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    solidity is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with solidity.  If not, see <http://www.gnu.org/licenses/>.
*/
/**
 * @author Christian <c@ethdev.com>
 * @author Gav Wood <g@ethdev.com>
 * @date 2014
 * Full-stack compiler that converts a source code string to bytecode.
 */


#include <libsolidity/interface/CompilerStack.h>

#include <libsolidity/interface/Version.h>
#include <libsolidity/analysis/SemVerHandler.h>
#include <libsolidity/ast/AST.h>
#include <libsolidity/parsing/Scanner.h>
#include <libsolidity/parsing/Parser.h>
#include <libsolidity/analysis/GlobalContext.h>
#include <libsolidity/analysis/NameAndTypeResolver.h>
#include <libsolidity/analysis/TypeChecker.h>
#include <libsolidity/analysis/DocStringAnalyser.h>
#include <libsolidity/analysis/StaticAnalyzer.h>
#include <libsolidity/analysis/PostTypeChecker.h>
#include <libsolidity/analysis/SyntaxChecker.h>
#include <libsolidity/analysis/ViewPureChecker.h>
#include <libsolidity/codegen/Compiler.h>
#include <libsolidity/formal/SMTChecker.h>
#include <libsolidity/interface/ABI.h>
#include <libsolidity/interface/Natspec.h>
#include <libsolidity/interface/GasEstimator.h>

#include <libevmasm/Exceptions.h>

#include <libdevcore/SwarmHash.h>
#include <libdevcore/JSON.h>

#include <json/json.h>

#include <boost/algorithm/string.hpp>

using namespace std;
using namespace dev;
using namespace dev::solidity;

void CompilerStack::setRemappings(vector<string> const& _remappings)
{
    vector<Remapping> remappings;
    for (auto const& remapping: _remappings)
    {
        auto eq = find(remapping.begin(), remapping.end(), '=');
        if (eq == remapping.end())
            continue; // ignore
        auto colon = find(remapping.begin(), eq, ':');
        Remapping r;
        r.context = colon == eq ? string() : string(remapping.begin(), colon);
        r.prefix = colon == eq ? string(remapping.begin(), eq) : string(colon + 1, eq);
        r.target = string(eq + 1, remapping.end());
        remappings.push_back(r);
    }
    swap(m_remappings, remappings);
}

void CompilerStack::reset(bool _keepSources)
{
    if (_keepSources)
    {
        m_stackState = SourcesSet;
        for (auto sourcePair: m_sources)
            sourcePair.second.reset();
    }
    else
    {
        m_stackState = Empty;
        m_sources.clear();
    }
    m_libraries.clear();
    m_optimize = false;
    m_optimizeRuns = 200;
    m_globalContext.reset();
    m_scopes.clear();
    m_sourceOrder.clear();
    m_contracts.clear();
    m_errorReporter.clear();
}

bool CompilerStack::addSource(string const& _name, string const& _content, bool _isLibrary)
{
    bool existed = m_sources.count(_name) != 0;
    reset(true);
    m_sources[_name].scanner = make_shared<Scanner>(CharStream(_content), _name);
    m_sources[_name].isLibrary = _isLibrary;
    m_stackState = SourcesSet;
    return existed;
}

bool CompilerStack::parse()
{
    //reset
    if(m_stackState != SourcesSet)
        return false;
    m_errorReporter.clear();
    ASTNode::resetID();

    if (SemVerVersion{string(VersionString)}.isPrerelease())
        m_errorReporter.warning("This is a pre-release compiler version, please do not use it in production.");

    vector<string> sourcesToParse;
    for (auto const& s: m_sources)
        sourcesToParse.push_back(s.first);
    for (size_t i = 0; i < sourcesToParse.size(); ++i)
    {
        string const& path = sourcesToParse[i];
        Source& source = m_sources[path];
        source.scanner->reset();
        source.ast = Parser(m_errorReporter).parse(source.scanner);
        if (!source.ast)
            solAssert(!Error::containsOnlyWarnings(m_errorReporter.errors()), "Parser returned null but did not report error.");
        else
        {
            source.ast->annotation().path = path;
            for (auto const& newSource: loadMissingSources(*source.ast, path))
            {
                string const& newPath = newSource.first;
                string const& newContents = newSource.second;
                m_sources[newPath].scanner = make_shared<Scanner>(CharStream(newContents), newPath);
                sourcesToParse.push_back(newPath);
            }
        }
    }
    if (Error::containsOnlyWarnings(m_errorReporter.errors()))
    {
        m_stackState = ParsingSuccessful;
        return true;
    }
    else
        return false;
}

bool CompilerStack::analyze()
{
    if (m_stackState != ParsingSuccessful)
        return false;
    resolveImports();

    bool noErrors = true;
    SyntaxChecker syntaxChecker(m_errorReporter);
    for (Source const* source: m_sourceOrder)
        if (!syntaxChecker.checkSyntax(*source->ast))
            noErrors = false;

    DocStringAnalyser docStringAnalyser(m_errorReporter);
    for (Source const* source: m_sourceOrder)
        if (!docStringAnalyser.analyseDocStrings(*source->ast))
            noErrors = false;

    m_globalContext = make_shared<GlobalContext>();
    NameAndTypeResolver resolver(m_globalContext->declarations(), m_scopes, m_errorReporter);
    for (Source const* source: m_sourceOrder)
        if (!resolver.registerDeclarations(*source->ast))
            return false;

    map<string, SourceUnit const*> sourceUnitsByName;
    for (auto& source: m_sources)
        sourceUnitsByName[source.first] = source.second.ast.get();
    for (Source const* source: m_sourceOrder)
        if (!resolver.performImports(*source->ast, sourceUnitsByName))
            return false;

    for (Source const* source: m_sourceOrder)
        for (ASTPointer<ASTNode> const& node: source->ast->nodes())
            if (ContractDefinition* contract = dynamic_cast<ContractDefinition*>(node.get()))
            {
                m_globalContext->setCurrentContract(*contract);
                if (!resolver.updateDeclaration(*m_globalContext->currentThis())) return false;
                if (!resolver.updateDeclaration(*m_globalContext->currentSuper())) return false;
                if (!resolver.resolveNamesAndTypes(*contract)) return false;

                // Note that we now reference contracts by their fully qualified names, and
                // thus contracts can only conflict if declared in the same source file.  This
                // already causes a double-declaration error elsewhere, so we do not report
                // an error here and instead silently drop any additional contracts we find.

                if (m_contracts.find(contract->fullyQualifiedName()) == m_contracts.end())
                    m_contracts[contract->fullyQualifiedName()].contract = contract;
            }

    TypeChecker typeChecker(m_errorReporter);
    for (Source const* source: m_sourceOrder)
        for (ASTPointer<ASTNode> const& node: source->ast->nodes())
            if (ContractDefinition* contract = dynamic_cast<ContractDefinition*>(node.get()))
                if (!typeChecker.checkTypeRequirements(*contract))
                    noErrors = false;

    if (noErrors)
    {
        PostTypeChecker postTypeChecker(m_errorReporter);
        for (Source const* source: m_sourceOrder)
            if (!postTypeChecker.check(*source->ast))
                noErrors = false;
    }

    if (noErrors)
    {
        StaticAnalyzer staticAnalyzer(m_errorReporter);
        for (Source const* source: m_sourceOrder)
            if (!staticAnalyzer.analyze(*source->ast))
                noErrors = false;
    }

    if (noErrors)
    {
        vector<ASTPointer<ASTNode>> ast;
        for (Source const* source: m_sourceOrder)
            ast.push_back(source->ast);

        if (!ViewPureChecker(ast, m_errorReporter).check())
            noErrors = false;
    }

    if (noErrors)
    {
        SMTChecker smtChecker(m_errorReporter, m_smtQuery);
        for (Source const* source: m_sourceOrder)
            smtChecker.analyze(*source->ast);
    }

    if (noErrors)
    {
        m_stackState = AnalysisSuccessful;
        return true;
    }
    else
        return false;
}

bool CompilerStack::parseAndAnalyze()
{
    return parse() && analyze();
}

bool CompilerStack::compile()
{
    if (m_stackState < AnalysisSuccessful)
        if (!parseAndAnalyze())
            return false;

    map<ContractDefinition const*, eth::Assembly const*> compiledContracts;
    for (Source const* source: m_sourceOrder)
        for (ASTPointer<ASTNode> const& node: source->ast->nodes())
            if (auto contract = dynamic_cast<ContractDefinition const*>(node.get()))
                compileContract(*contract, compiledContracts);
    this->link();
    m_stackState = CompilationSuccessful;
    return true;
}

void CompilerStack::link()
{
    for (auto& contract: m_contracts)
    {
        contract.second.object.link(m_libraries);
        contract.second.runtimeObject.link(m_libraries);
        contract.second.cloneObject.link(m_libraries);
    }
}

vector<string> CompilerStack::contractNames() const
{
    if (m_stackState < AnalysisSuccessful)
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Parsing was not successful."));
    vector<string> contractNames;
    for (auto const& contract: m_contracts)
        contractNames.push_back(contract.first);
    return contractNames;
}

eth::AssemblyItems const* CompilerStack::assemblyItems(string const& _contractName) const
{
    Contract const& currentContract = contract(_contractName);
    return currentContract.compiler ? &contract(_contractName).compiler->assemblyItems() : nullptr;
}

eth::AssemblyItems const* CompilerStack::runtimeAssemblyItems(string const& _contractName) const
{
    Contract const& currentContract = contract(_contractName);
    return currentContract.compiler ? &contract(_contractName).compiler->runtimeAssemblyItems() : nullptr;
}

string const* CompilerStack::sourceMapping(string const& _contractName) const
{
    Contract const& c = contract(_contractName);
    if (!c.sourceMapping)
    {
        if (auto items = assemblyItems(_contractName))
            c.sourceMapping.reset(new string(computeSourceMapping(*items)));
    }
    return c.sourceMapping.get();
}

string const* CompilerStack::runtimeSourceMapping(string const& _contractName) const
{
    Contract const& c = contract(_contractName);
    if (!c.runtimeSourceMapping)
    {
        if (auto items = runtimeAssemblyItems(_contractName))
            c.runtimeSourceMapping.reset(new string(computeSourceMapping(*items)));
    }
    return c.runtimeSourceMapping.get();
}

std::string const CompilerStack::filesystemFriendlyName(string const& _contractName) const
{
    // Look up the contract (by its fully-qualified name)
    Contract const& matchContract = m_contracts.at(_contractName);
    // Check to see if it could collide on name
    for (auto const& contract: m_contracts)
    {
        if (contract.second.contract->name() == matchContract.contract->name() &&
                contract.second.contract != matchContract.contract)
        {
            // If it does, then return its fully-qualified name, made fs-friendly
            std::string friendlyName = boost::algorithm::replace_all_copy(_contractName, "/", "_");
            boost::algorithm::replace_all(friendlyName, ":", "_");
            boost::algorithm::replace_all(friendlyName, ".", "_");
            return friendlyName;
        }
    }
    // If no collision, return the contract's name
    return matchContract.contract->name();
}

eth::LinkerObject const& CompilerStack::object(string const& _contractName) const
{
    return contract(_contractName).object;
}

eth::LinkerObject const& CompilerStack::runtimeObject(string const& _contractName) const
{
    return contract(_contractName).runtimeObject;
}

eth::LinkerObject const& CompilerStack::cloneObject(string const& _contractName) const
{
    return contract(_contractName).cloneObject;
}

/// FIXME: cache this string
string CompilerStack::assemblyString(string const& _contractName, StringMap _sourceCodes) const
{
    Contract const& currentContract = contract(_contractName);
    if (currentContract.compiler)
        return currentContract.compiler->assemblyString(_sourceCodes);
    else
        return string();
}

/// FIXME: cache the JSON
Json::Value CompilerStack::assemblyJSON(string const& _contractName, StringMap _sourceCodes) const
{
    Contract const& currentContract = contract(_contractName);
    if (currentContract.compiler)
        return currentContract.compiler->assemblyJSON(_sourceCodes);
    else
        return Json::Value();
}

vector<string> CompilerStack::sourceNames() const
{
    vector<string> names;
    for (auto const& s: m_sources)
        names.push_back(s.first);
    return names;
}

map<string, unsigned> CompilerStack::sourceIndices() const
{
    map<string, unsigned> indices;
    unsigned index = 0;
    for (auto const& s: m_sources)
        indices[s.first] = index++;
    return indices;
}

Json::Value const& CompilerStack::contractABI(string const& _contractName) const
{
    return contractABI(contract(_contractName));
}

Json::Value const& CompilerStack::contractABI(Contract const& _contract) const
{
    if (m_stackState < AnalysisSuccessful)
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Parsing was not successful."));

    solAssert(_contract.contract, "");

    // caches the result
    if (!_contract.abi)
        _contract.abi.reset(new Json::Value(ABI::generate(*_contract.contract)));

    return *_contract.abi;
}

Json::Value const& CompilerStack::natspecUser(string const& _contractName) const
{
    return natspecUser(contract(_contractName));
}

Json::Value const& CompilerStack::natspecUser(Contract const& _contract) const
{
    if (m_stackState < AnalysisSuccessful)
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Parsing was not successful."));

    solAssert(_contract.contract, "");

    // caches the result
    if (!_contract.userDocumentation)
        _contract.userDocumentation.reset(new Json::Value(Natspec::userDocumentation(*_contract.contract)));

    return *_contract.userDocumentation;
}

Json::Value const& CompilerStack::natspecDev(string const& _contractName) const
{
    return natspecDev(contract(_contractName));
}

Json::Value const& CompilerStack::natspecDev(Contract const& _contract) const
{
    if (m_stackState < AnalysisSuccessful)
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Parsing was not successful."));

    solAssert(_contract.contract, "");

    // caches the result
    if (!_contract.devDocumentation)
        _contract.devDocumentation.reset(new Json::Value(Natspec::devDocumentation(*_contract.contract)));

    return *_contract.devDocumentation;
}

Json::Value CompilerStack::methodIdentifiers(string const& _contractName) const
{
    Json::Value methodIdentifiers(Json::objectValue);
    for (auto const& it: contractDefinition(_contractName).interfaceFunctions())
        methodIdentifiers[it.second->externalSignature()] = toHex(it.first.ref());
    return methodIdentifiers;
}

string const& CompilerStack::metadata(string const& _contractName) const
{
    if (m_stackState != CompilationSuccessful)
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Compilation was not successful."));

    return contract(_contractName).metadata;
}

Scanner const& CompilerStack::scanner(string const& _sourceName) const
{
    if (m_stackState < SourcesSet)
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("No sources set."));

    return *source(_sourceName).scanner;
}

SourceUnit const& CompilerStack::ast(string const& _sourceName) const
{
    if (m_stackState < ParsingSuccessful)
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Parsing was not successful."));

    return *source(_sourceName).ast;
}

ContractDefinition const& CompilerStack::contractDefinition(string const& _contractName) const
{
    if (m_stackState != CompilationSuccessful)
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Compilation was not successful."));

    return *contract(_contractName).contract;
}

size_t CompilerStack::functionEntryPoint(
    std::string const& _contractName,
    FunctionDefinition const& _function
) const
{
    shared_ptr<Compiler> const& compiler = contract(_contractName).compiler;
    if (!compiler)
        return 0;
    eth::AssemblyItem tag = compiler->functionEntryLabel(_function);
    if (tag.type() == eth::UndefinedItem)
        return 0;
    eth::AssemblyItems const& items = compiler->runtimeAssemblyItems();
    for (size_t i = 0; i < items.size(); ++i)
        if (items.at(i).type() == eth::Tag && items.at(i).data() == tag.data())
            return i;
    return 0;
}

tuple<int, int, int, int> CompilerStack::positionFromSourceLocation(SourceLocation const& _sourceLocation) const
{
    int startLine;
    int startColumn;
    int endLine;
    int endColumn;
    tie(startLine, startColumn) = scanner(*_sourceLocation.sourceName).translatePositionToLineColumn(_sourceLocation.start);
    tie(endLine, endColumn) = scanner(*_sourceLocation.sourceName).translatePositionToLineColumn(_sourceLocation.end);

    return make_tuple(++startLine, ++startColumn, ++endLine, ++endColumn);
}

StringMap CompilerStack::loadMissingSources(SourceUnit const& _ast, std::string const& _sourcePath)
{
    StringMap newSources;
    for (auto const& node: _ast.nodes())
        if (ImportDirective const* import = dynamic_cast<ImportDirective*>(node.get()))
        {
            string importPath = absolutePath(import->path(), _sourcePath);
            // The current value of `path` is the absolute path as seen from this source file.
            // We first have to apply remappings before we can store the actual absolute path
            // as seen globally.
            importPath = applyRemapping(importPath, _sourcePath);
            import->annotation().absolutePath = importPath;
            if (m_sources.count(importPath) || newSources.count(importPath))
                continue;

            ReadCallback::Result result{false, string("File not supplied initially.")};
            if (m_readFile)
                result = m_readFile(importPath);

            if (result.success)
                newSources[importPath] = result.responseOrErrorMessage;
            else
            {
                m_errorReporter.parserError(
                    import->location(),
                    string("Source \"" + importPath + "\" not found: " + result.responseOrErrorMessage)
                );
                continue;
            }
        }
    return newSources;
}

string CompilerStack::applyRemapping(string const& _path, string const& _context)
{
    // Try to find the longest prefix match in all remappings that are active in the current context.
    auto isPrefixOf = [](string const& _a, string const& _b)
    {
        if (_a.length() > _b.length())
            return false;
        return std::equal(_a.begin(), _a.end(), _b.begin());
    };

    size_t longestPrefix = 0;
    size_t longestContext = 0;
    string bestMatchTarget;

    for (auto const& redir: m_remappings)
    {
        string context = sanitizePath(redir.context);
        string prefix = sanitizePath(redir.prefix);

        // Skip if current context is closer
        if (context.length() < longestContext)
            continue;
        // Skip if redir.context is not a prefix of _context
        if (!isPrefixOf(context, _context))
            continue;
        // Skip if we already have a closer prefix match.
        if (prefix.length() < longestPrefix && context.length() == longestContext)
            continue;
        // Skip if the prefix does not match.
        if (!isPrefixOf(prefix, _path))
            continue;

        longestContext = context.length();
        longestPrefix = prefix.length();
        bestMatchTarget = sanitizePath(redir.target);
    }
    string path = bestMatchTarget;
    path.append(_path.begin() + longestPrefix, _path.end());
    return path;
}

void CompilerStack::resolveImports()
{
    // topological sorting (depth first search) of the import graph, cutting potential cycles
    vector<Source const*> sourceOrder;
    set<Source const*> sourcesSeen;

    function<void(Source const*)> toposort = [&](Source const* _source)
    {
        if (sourcesSeen.count(_source))
            return;
        sourcesSeen.insert(_source);
        for (ASTPointer<ASTNode> const& node: _source->ast->nodes())
            if (ImportDirective const* import = dynamic_cast<ImportDirective*>(node.get()))
            {
                string const& path = import->annotation().absolutePath;
                solAssert(!path.empty(), "");
                solAssert(m_sources.count(path), "");
                import->annotation().sourceUnit = m_sources[path].ast.get();
                toposort(&m_sources[path]);
            }
        sourceOrder.push_back(_source);
    };

    for (auto const& sourcePair: m_sources)
        if (!sourcePair.second.isLibrary)
            toposort(&sourcePair.second);

    swap(m_sourceOrder, sourceOrder);
}

string CompilerStack::absolutePath(string const& _path, string const& _reference) const
{
    using path = boost::filesystem::path;
    path p(_path);
    // Anything that does not start with `.` is an absolute path.
    if (p.begin() == p.end() || (*p.begin() != "." && *p.begin() != ".."))
        return _path;
    path result(_reference);
    result.remove_filename();
    for (path::iterator it = p.begin(); it != p.end(); ++it)
        if (*it == "..")
            result = result.parent_path();
        else if (*it != ".")
            result /= *it;
    return result.generic_string();
}

namespace
{
bool onlySafeExperimentalFeaturesActivated(set<ExperimentalFeature> const& features)
{
    for (auto const feature: features)
        if (!ExperimentalFeatureOnlyAnalysis.count(feature))
            return false;
    return true;
}
}

void CompilerStack::compileContract(
    ContractDefinition const& _contract,
    map<ContractDefinition const*, eth::Assembly const*>& _compiledContracts
)
{
    if (
        _compiledContracts.count(&_contract) ||
        !_contract.annotation().unimplementedFunctions.empty() ||
        !_contract.constructorIsPublic()
    )
        return;
    for (auto const* dependency: _contract.annotation().contractDependencies)
        compileContract(*dependency, _compiledContracts);

    shared_ptr<Compiler> compiler = make_shared<Compiler>(m_optimize, m_optimizeRuns);
    Contract& compiledContract = m_contracts.at(_contract.fullyQualifiedName());
    string metadata = createMetadata(compiledContract);
    bytes cborEncodedHash =
        // CBOR-encoding of the key "bzzr0"
        bytes{0x65, 'b', 'z', 'z', 'r', '0'}+
        // CBOR-encoding of the hash
        bytes{0x58, 0x20} + dev::swarmHash(metadata).asBytes();
    bytes cborEncodedMetadata;
    if (onlySafeExperimentalFeaturesActivated(_contract.sourceUnit().annotation().experimentalFeatures))
        cborEncodedMetadata =
            // CBOR-encoding of {"bzzr0": dev::swarmHash(metadata)}
            bytes{0xa1} +
            cborEncodedHash;
    else
        cborEncodedMetadata =
            // CBOR-encoding of {"bzzr0": dev::swarmHash(metadata), "experimental": true}
            bytes{0xa2} +
            cborEncodedHash +
            bytes{0x6c, 'e', 'x', 'p', 'e', 'r', 'i', 'm', 'e', 'n', 't', 'a', 'l', 0xf5};
    solAssert(cborEncodedMetadata.size() <= 0xffff, "Metadata too large");
    // 16-bit big endian length
    cborEncodedMetadata += toCompactBigEndian(cborEncodedMetadata.size(), 2);
    compiler->compileContract(_contract, _compiledContracts, cborEncodedMetadata);
    compiledContract.compiler = compiler;

    try
    {
        compiledContract.object = compiler->assembledObject();
    }
    catch(eth::OptimizerException const&)
    {
        solAssert(false, "Assembly optimizer exception for bytecode");
    }
    catch(eth::AssemblyException const&)
    {
        solAssert(false, "Assembly exception for bytecode");
    }

    try
    {
        compiledContract.runtimeObject = compiler->runtimeObject();
    }
    catch(eth::OptimizerException const&)
    {
        solAssert(false, "Assembly optimizer exception for deployed bytecode");
    }
    catch(eth::AssemblyException const&)
    {
        solAssert(false, "Assembly exception for deployed bytecode");
    }

    compiledContract.metadata = metadata;
    _compiledContracts[compiledContract.contract] = &compiler->assembly();

    try
    {
        Compiler cloneCompiler(m_optimize, m_optimizeRuns);
        cloneCompiler.compileClone(_contract, _compiledContracts);
        compiledContract.cloneObject = cloneCompiler.assembledObject();
    }
    catch (eth::AssemblyException const&)
    {
        // In some cases (if the constructor requests a runtime function), it is not
        // possible to compile the clone.

        // TODO: Report error / warning
    }
}

CompilerStack::Contract const& CompilerStack::contract(string const& _contractName) const
{
    if (m_contracts.empty())
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("No compiled contracts found."));
    string contractName = _contractName;
    if (_contractName.empty())
        // try to find some user-supplied contract
        for (auto const& it: m_sources)
            for (ASTPointer<ASTNode> const& node: it.second.ast->nodes())
                if (auto contract = dynamic_cast<ContractDefinition const*>(node.get()))
                    contractName = contract->fullyQualifiedName();
    auto it = m_contracts.find(contractName);
    // To provide a measure of backward-compatibility, if a contract is not located by its
    // fully-qualified name, a lookup will be attempted purely on the contract's name to see
    // if anything will satisfy.
    if (it == m_contracts.end() && contractName.find(":") == string::npos)
    {
        for (auto const& contractEntry: m_contracts)
        {
            stringstream ss;
            ss.str(contractEntry.first);
            // All entries are <source>:<contract>
            string source;
            string foundName;
            getline(ss, source, ':');
            getline(ss, foundName, ':');
            if (foundName == contractName) return contractEntry.second;
        }
        // If we get here, both lookup methods failed.
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Contract " + _contractName + " not found."));
    }
    return it->second;
}

CompilerStack::Source const& CompilerStack::source(string const& _sourceName) const
{
    auto it = m_sources.find(_sourceName);
    if (it == m_sources.end())
        BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Given source file not found."));

    return it->second;
}

string CompilerStack::createMetadata(Contract const& _contract) const
{
    Json::Value meta;
    meta["version"] = 1;
    meta["language"] = "Solidity";
    meta["compiler"]["version"] = VersionStringStrict;

    /// All the source files (including self), which should be included in the metadata.
    set<string> referencedSources;
    referencedSources.insert(_contract.contract->sourceUnit().annotation().path);
    for (auto const sourceUnit: _contract.contract->sourceUnit().referencedSourceUnits(true))
        referencedSources.insert(sourceUnit->annotation().path);

    meta["sources"] = Json::objectValue;
    for (auto const& s: m_sources)
    {
        if (!referencedSources.count(s.first))
            continue;

        solAssert(s.second.scanner, "Scanner not available");
        meta["sources"][s.first]["keccak256"] =
            "0x" + toHex(dev::keccak256(s.second.scanner->source()).asBytes());
        if (m_metadataLiteralSources)
            meta["sources"][s.first]["content"] = s.second.scanner->source();
        else
        {
            meta["sources"][s.first]["urls"] = Json::arrayValue;
            meta["sources"][s.first]["urls"].append(
                "bzzr://" + toHex(dev::swarmHash(s.second.scanner->source()).asBytes())
            );
        }
    }
    meta["settings"]["optimizer"]["enabled"] = m_optimize;
    meta["settings"]["optimizer"]["runs"] = m_optimizeRuns;
    meta["settings"]["compilationTarget"][_contract.contract->sourceUnitName()] =
        _contract.contract->annotation().canonicalName;

    meta["settings"]["remappings"] = Json::arrayValue;
    set<string> remappings;
    for (auto const& r: m_remappings)
        remappings.insert(r.context + ":" + r.prefix + "=" + r.target);
    for (auto const& r: remappings)
        meta["settings"]["remappings"].append(r);

    meta["settings"]["libraries"] = Json::objectValue;
    for (auto const& library: m_libraries)
        meta["settings"]["libraries"][library.first] = "0x" + toHex(library.second.asBytes());

    meta["output"]["abi"] = contractABI(_contract);
    meta["output"]["userdoc"] = natspecUser(_contract);
    meta["output"]["devdoc"] = natspecDev(_contract);

    return jsonCompactPrint(meta);
}

string CompilerStack::computeSourceMapping(eth::AssemblyItems const& _items) const
{
    string ret;
    map<string, unsigned> sourceIndicesMap = sourceIndices();
    int prevStart = -1;
    int prevLength = -1;
    int prevSourceIndex = -1;
    char prevJump = 0;
    for (auto const& item: _items)
    {
        if (!ret.empty())
            ret += ";";

        SourceLocation const& location = item.location();
        int length = location.start != -1 && location.end != -1 ? location.end - location.start : -1;
        int sourceIndex =
            location.sourceName && sourceIndicesMap.count(*location.sourceName) ?
            sourceIndicesMap.at(*location.sourceName) :
            -1;
        char jump = '-';
        if (item.getJumpType() == eth::AssemblyItem::JumpType::IntoFunction)
            jump = 'i';
        else if (item.getJumpType() == eth::AssemblyItem::JumpType::OutOfFunction)
            jump = 'o';

        unsigned components = 4;
        if (jump == prevJump)
        {
            components--;
            if (sourceIndex == prevSourceIndex)
            {
                components--;
                if (length == prevLength)
                {
                    components--;
                    if (location.start == prevStart)
                        components--;
                }
            }
        }

        if (components-- > 0)
        {
            if (location.start != prevStart)
                ret += std::to_string(location.start);
            if (components-- > 0)
            {
                ret += ':';
                if (length != prevLength)
                    ret += std::to_string(length);
                if (components-- > 0)
                {
                    ret += ':';
                    if (sourceIndex != prevSourceIndex)
                        ret += std::to_string(sourceIndex);
                    if (components-- > 0)
                    {
                        ret += ':';
                        if (jump != prevJump)
                            ret += jump;
                    }
                }
            }
        }

        prevStart = location.start;
        prevLength = length;
        prevSourceIndex = sourceIndex;
        prevJump = jump;
    }
    return ret;
}

namespace
{

Json::Value gasToJson(GasEstimator::GasConsumption const& _gas)
{
    if (_gas.isInfinite)
        return Json::Value("infinite");
    else
        return Json::Value(toString(_gas.value));
}

}

Json::Value CompilerStack::gasEstimates(string const& _contractName) const
{
    if (!assemblyItems(_contractName) && !runtimeAssemblyItems(_contractName))
        return Json::Value();

    using Gas = GasEstimator::GasConsumption;
    Json::Value output(Json::objectValue);

    if (eth::AssemblyItems const* items = assemblyItems(_contractName))
    {
        Gas executionGas = GasEstimator::functionalEstimation(*items);
        u256 bytecodeSize(runtimeObject(_contractName).bytecode.size());
        Gas codeDepositGas = bytecodeSize * eth::GasCosts::createDataGas;

        Json::Value creation(Json::objectValue);
        creation["codeDepositCost"] = gasToJson(codeDepositGas);
        creation["executionCost"] = gasToJson(executionGas);
        /// TODO: implement + overload to avoid the need of +=
        executionGas += codeDepositGas;
        creation["totalCost"] = gasToJson(executionGas);
        output["creation"] = creation;
    }

    if (eth::AssemblyItems const* items = runtimeAssemblyItems(_contractName))
    {
        /// External functions
        ContractDefinition const& contract = contractDefinition(_contractName);
        Json::Value externalFunctions(Json::objectValue);
        for (auto it: contract.interfaceFunctions())
        {
            string sig = it.second->externalSignature();
            externalFunctions[sig] = gasToJson(GasEstimator::functionalEstimation(*items, sig));
        }

        if (contract.fallbackFunction())
            /// This needs to be set to an invalid signature in order to trigger the fallback,
            /// without the shortcut (of CALLDATSIZE == 0), and therefore to receive the upper bound.
            /// An empty string ("") would work to trigger the shortcut only.
            externalFunctions[""] = gasToJson(GasEstimator::functionalEstimation(*items, "INVALID"));

        if (!externalFunctions.empty())
            output["external"] = externalFunctions;

        /// Internal functions
        Json::Value internalFunctions(Json::objectValue);
        for (auto const& it: contract.definedFunctions())
        {
            /// Exclude externally visible functions, constructor and the fallback function
            if (it->isPartOfExternalInterface() || it->isConstructor() || it->isFallback())
                continue;

            size_t entry = functionEntryPoint(_contractName, *it);
            GasEstimator::GasConsumption gas = GasEstimator::GasConsumption::infinite();
            if (entry > 0)
                gas = GasEstimator::functionalEstimation(*items, entry, *it);

            /// TODO: This could move into a method shared with externalSignature()
            FunctionType type(*it);
            string sig = it->name() + "(";
            auto paramTypes = type.parameterTypes();
            for (auto it = paramTypes.begin(); it != paramTypes.end(); ++it)
                sig += (*it)->toString() + (it + 1 == paramTypes.end() ? "" : ",");
            sig += ")";

            internalFunctions[sig] = gasToJson(gas);
        }

        if (!internalFunctions.empty())
            output["internal"] = internalFunctions;
    }

    return output;
}