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**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
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** This file is part of Qt for Python.
**
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** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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#include "compilersupport.h"
#include "header_paths.h"

#include <reporthandler.h>

#include <QtCore/QDebug>
#include <QtCore/QDir>
#include <QtCore/QFile>
#include <QtCore/QFileInfo>
#include <QtCore/QProcess>
#include <QtCore/QStandardPaths>
#include <QtCore/QStringList>
#include <QtCore/QVersionNumber>

#include <clang-c/Index.h>

#include <string.h>
#include <algorithm>
#include <iterator>

namespace clang {

QVersionNumber libClangVersion()
{
    return QVersionNumber(CINDEX_VERSION_MAJOR, CINDEX_VERSION_MINOR);
}

static bool runProcess(const QString &program, const QStringList &arguments,
                       QByteArray *stdOutIn = nullptr, QByteArray *stdErrIn = nullptr)
{
    QProcess process;
    process.start(program, arguments, QProcess::ReadWrite);
    if (!process.waitForStarted()) {
        qWarning().noquote().nospace() << "Unable to start "
            << process.program() << ": " << process.errorString();
        return false;
    }
    process.closeWriteChannel();
    const bool finished = process.waitForFinished();
    const QByteArray stdErr = process.readAllStandardError();
    if (stdErrIn)
        *stdErrIn = stdErr;
    if (stdOutIn)
        *stdOutIn = process.readAllStandardOutput();

    if (!finished) {
        qWarning().noquote().nospace() << process.program() << " timed out: " << stdErr;
        process.kill();
        return false;
    }

    if (process.exitStatus() != QProcess::NormalExit) {
        qWarning().noquote().nospace() << process.program() << " crashed: " << stdErr;
        return false;
    }

    if (process.exitCode() != 0) {
        qWarning().noquote().nospace() <<  process.program() << " exited "
            << process.exitCode() << ": " << stdErr;
        return false;
    }

    return true;
}

#if defined(Q_CC_GNU)

static QByteArray frameworkPath() { return QByteArrayLiteral(" (framework directory)"); }

#if defined(Q_OS_MACOS)
static void filterHomebrewHeaderPaths(HeaderPaths &headerPaths)
{
    QByteArray homebrewPrefix = qgetenv("HOMEBREW_OPT");

    // If HOMEBREW_OPT is found we assume that the build is happening
    // inside a brew environment, which means we need to filter out
    // the -isystem flags added by the brew clang shim. This is needed
    // because brew passes the Qt include paths as system include paths
    // and because our parser ignores system headers, Qt classes won't
    // be found and thus compilation errors will occur.
    if (homebrewPrefix.isEmpty())
        return;

    qCInfo(lcShiboken) << "Found HOMEBREW_OPT with value:" << homebrewPrefix
                       << "Assuming homebrew build environment.";

    HeaderPaths::iterator it = headerPaths.begin();
    while (it != headerPaths.end()) {
        if (it->path.startsWith(homebrewPrefix)) {
            qCInfo(lcShiboken) << "Filtering out homebrew include path: "
                               << it->path;
            it = headerPaths.erase(it);
        } else {
            ++it;
        }
    }
}
#endif

// Determine g++'s internal include paths from the output of
// g++ -E -x c++ - -v </dev/null
// Output looks like:
// #include <...> search starts here:
// /usr/local/include
// /System/Library/Frameworks (framework directory)
// End of search list.
static HeaderPaths gppInternalIncludePaths(const QString &compiler)
{
    HeaderPaths result;
    QStringList arguments;
    arguments << QStringLiteral("-E") << QStringLiteral("-x") << QStringLiteral("c++")
         << QStringLiteral("-") << QStringLiteral("-v");
    QByteArray stdOut;
    QByteArray stdErr;
    if (!runProcess(compiler, arguments, &stdOut, &stdErr))
        return result;
    const QByteArrayList stdErrLines = stdErr.split('\n');
    bool isIncludeDir = false;
    for (const QByteArray &line : stdErrLines) {
        if (isIncludeDir) {
            if (line.startsWith(QByteArrayLiteral("End of search list"))) {
                isIncludeDir = false;
            } else {
                HeaderPath headerPath{line.trimmed(), HeaderType::System};
                if (headerPath.path.endsWith(frameworkPath())) {
                    headerPath.type = HeaderType::FrameworkSystem;
                    headerPath.path.truncate(headerPath.path.size() - frameworkPath().size());
                }
                result.append(headerPath);
            }
        } else if (line.startsWith(QByteArrayLiteral("#include <...> search starts here"))) {
            isIncludeDir = true;
        }
    }

#if defined(Q_OS_MACOS)
    filterHomebrewHeaderPaths(result);
#endif
    return result;
}
#endif // Q_CC_MSVC

// Detect Vulkan as supported from Qt 5.10 by checking the environment variables.
static void detectVulkan(HeaderPaths *headerPaths)
{
    static const char *vulkanVariables[] = {"VULKAN_SDK", "VK_SDK_PATH"};
    for (const char *vulkanVariable : vulkanVariables) {
        if (qEnvironmentVariableIsSet(vulkanVariable)) {
            const QByteArray path = qgetenv(vulkanVariable) + QByteArrayLiteral("/include");
            headerPaths->append(HeaderPath{path, HeaderType::System});
            break;
        }
    }
}

#if defined(Q_CC_GNU)
enum class LinuxDistribution { RedHat, CentOs, Other };

static LinuxDistribution linuxDistribution()
{
    const QString &productType = QSysInfo::productType();
    if (productType == QLatin1String("rhel"))
        return LinuxDistribution::RedHat;
    if (productType == QLatin1String("centos"))
        return LinuxDistribution::CentOs;
    return LinuxDistribution::Other;
}

static bool checkProductVersion(const QVersionNumber &minimum,
                                const QVersionNumber &excludedMaximum)
{
    const QVersionNumber osVersion = QVersionNumber::fromString(QSysInfo::productVersion());
    return osVersion.isNull() || (osVersion >= minimum && osVersion < excludedMaximum);
}

static inline bool needsGppInternalHeaders()
{
    const LinuxDistribution distro = linuxDistribution();
    switch (distro) {
    case LinuxDistribution::RedHat:
    case LinuxDistribution::CentOs:
        return checkProductVersion(QVersionNumber(7), QVersionNumber(8));
    case LinuxDistribution::Other:
        break;
    }
    return false;
}
#endif // Q_CC_GNU

// For MSVC, we set the MS compatibility version and let Clang figure out its own
// options and include paths.
// For the others, we pass "-nostdinc" since libclang tries to add it's own system
// include paths, which together with the clang compiler paths causes some clash
// which causes std types not being found and construct -I/-F options from the
// include paths of the host compiler.

#ifdef Q_CC_CLANG
static QByteArray noStandardIncludeOption() { return QByteArrayLiteral("-nostdinc"); }
#endif

// The clang builtin includes directory is used to find the definitions for
// intrinsic functions and builtin types. It is necessary to use the clang
// includes to prevent redefinition errors. The default toolchain includes
// should be picked up automatically by clang without specifying
// them implicitly.

#if defined(Q_OS_UNIX) && !defined(Q_OS_DARWIN)
#  define NEED_CLANG_BUILTIN_INCLUDES 1
#else
#  define NEED_CLANG_BUILTIN_INCLUDES 0
#endif

#if NEED_CLANG_BUILTIN_INCLUDES
static QString findClang()
{
    for (const char *envVar : {"LLVM_INSTALL_DIR", "CLANG_INSTALL_DIR"}) {
        if (qEnvironmentVariableIsSet(envVar)) {
            const QString path = QFile::decodeName(qgetenv(envVar));
            if (QFileInfo::exists(path))
                return path;
        }
    }
    const QString llvmConfig =
        QStandardPaths::findExecutable(QLatin1String("llvm-config"));
    if (!llvmConfig.isEmpty()) {
        QByteArray stdOut;
        if (runProcess(llvmConfig, QStringList{QLatin1String("--prefix")}, &stdOut)) {
            const QString path = QFile::decodeName(stdOut.trimmed());
            if (QFileInfo::exists(path))
                return path;
        }
    }
    return QString();
}

static QString findClangBuiltInIncludesDir()
{
    // Find the include directory of the highest version.
    const QString clangPath = findClang();
    if (!clangPath.isEmpty()) {
        QString candidate;
        QVersionNumber lastVersionNumber(1, 0, 0);
        QDir clangDir(clangPath + QLatin1String("/lib/clang"));
        const QFileInfoList versionDirs =
            clangDir.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot);
        for (const QFileInfo &fi : versionDirs) {
            const QString fileName = fi.fileName();
            if (fileName.at(0).isDigit()) {
                const QVersionNumber versionNumber = QVersionNumber::fromString(fileName.at(0));
                if (!versionNumber.isNull() && versionNumber > lastVersionNumber) {
                    candidate = fi.absoluteFilePath();
                    lastVersionNumber = versionNumber;
                }
            }
        }
        if (!candidate.isEmpty())
            return candidate + QStringLiteral("/include");
    }
    return QString();
}
#endif // NEED_CLANG_BUILTIN_INCLUDES

// Returns clang options needed for emulating the host compiler
QByteArrayList emulatedCompilerOptions()
{
    QByteArrayList result;
#if defined(Q_CC_MSVC)
    HeaderPaths headerPaths;
    result.append(QByteArrayLiteral("-fms-compatibility-version=19"));
    result.append(QByteArrayLiteral("-Wno-microsoft-enum-value"));
#elif defined(Q_CC_CLANG)
    HeaderPaths headerPaths = gppInternalIncludePaths(QStringLiteral("clang++"));
    result.append(noStandardIncludeOption());
#elif defined(Q_CC_GNU)
    HeaderPaths headerPaths;

#if NEED_CLANG_BUILTIN_INCLUDES
    const QString clangBuiltinIncludesDir =
        QDir::toNativeSeparators(findClangBuiltInIncludesDir());
    if (clangBuiltinIncludesDir.isEmpty()) {
        qCWarning(lcShiboken, "Unable to locate Clang's built-in include directory "
                  "(neither by checking the environment variables LLVM_INSTALL_DIR, CLANG_INSTALL_DIR "
                  " nor running llvm-config). This may lead to parse errors.");
    } else {
        qCInfo(lcShiboken, "CLANG builtins includes directory: %s",
               qPrintable(clangBuiltinIncludesDir));
        headerPaths.append(HeaderPath{QFile::encodeName(clangBuiltinIncludesDir),
                                      HeaderType::System});
    }
#endif // NEED_CLANG_BUILTIN_INCLUDES

    // Append the c++ include paths since Clang is unable to find <list> etc
    // on RHEL 7 with g++ 6.3 or CentOS 7.2.
    // A fix for this has been added to Clang 5.0, so, the code can be removed
    // once Clang 5.0 is the minimum version.
    if (needsGppInternalHeaders()) {
        const HeaderPaths gppPaths = gppInternalIncludePaths(QStringLiteral("g++"));
        for (const HeaderPath &h : gppPaths) {
            if (h.path.contains("c++"))
                headerPaths.append(h);
        }
    }
#else
    HeaderPaths headerPaths;
#endif
    detectVulkan(&headerPaths);
    std::transform(headerPaths.cbegin(), headerPaths.cend(),
                   std::back_inserter(result), HeaderPath::includeOption);
    return result;
}

LanguageLevel emulatedCompilerLanguageLevel()
{
#if defined(Q_CC_MSVC) && _MSC_VER > 1900
    // Fixes constexpr errors in MSVC2017 library headers with Clang 4.1..5.X (0.45 == Clang 6).
    if (libClangVersion() < QVersionNumber(0, 45))
        return LanguageLevel::Cpp1Z;
#endif // Q_CC_MSVC && _MSC_VER > 1900
    return LanguageLevel::Cpp14; // otherwise, t.h is parsed as "C"
}

struct LanguageLevelMapping
{
    const char *option;
    LanguageLevel level;
};

static const LanguageLevelMapping languageLevelMapping[] =
{
    {"c++11", LanguageLevel::Cpp11},
    {"c++14", LanguageLevel::Cpp14},
    {"c++17", LanguageLevel::Cpp17},
    {"c++20", LanguageLevel::Cpp20},
    {"c++1z", LanguageLevel::Cpp1Z}
};

const char *languageLevelOption(LanguageLevel l)
{
    for (const LanguageLevelMapping &m : languageLevelMapping) {
        if (m.level == l)
            return m.option;
    }
    return nullptr;
}

LanguageLevel languageLevelFromOption(const char *o)
{
    for (const LanguageLevelMapping &m : languageLevelMapping) {
        if (!strcmp(m.option, o))
            return m.level;
    }
    return LanguageLevel::Default;
}

} // namespace clang