TypeUtils.cpp

/*
   This file is part of the clazy static checker.

  Copyright (C) 2016 Sergio Martins <smartins@kde.org>

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Library General Public
  License as published by the Free Software Foundation; either
  version 2 of the License, or (at your option) any later version.

  This library 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
  Library General Public License for more details.

  You should have received a copy of the GNU Library General Public License
  along with this library; see the file COPYING.LIB.  If not, write to
  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  Boston, MA 02110-1301, USA.
*/

#include "TypeUtils.h"
#include "Utils.h"

#include <clang/Frontend/CompilerInstance.h>
#include <clang/AST/ASTContext.h>
#include <clang/AST/StmtCXX.h>
#include <clang/AST/DeclCXX.h>

using namespace clang;

int TypeUtils::sizeOfPointer(const clang::CompilerInstance &ci, clang::QualType qt)
{
    if (!qt.getTypePtrOrNull())
        return -1;
    // HACK: What's a better way of getting the size of a pointer ?
    auto &astContext = ci.getASTContext();
    return astContext.getTypeSize(astContext.getPointerType(qt));
}

bool TypeUtils::classifyQualType(const CompilerInstance &ci, const VarDecl *varDecl, QualTypeClassification &classif, clang::Stmt *body)
{
    if (!varDecl)
        return false;

    QualType qualType = TypeUtils::unrefQualType(varDecl->getType());
    const Type *paramType = qualType.getTypePtrOrNull();
    if (!paramType || paramType->isIncompleteType())
        return false;

    classif.size_of_T = ci.getASTContext().getTypeSize(qualType) / 8;
    classif.isBig = classif.size_of_T > 16;
    CXXRecordDecl *recordDecl = paramType->getAsCXXRecordDecl();
    classif.isNonTriviallyCopyable = recordDecl && (recordDecl->hasNonTrivialCopyConstructor() || recordDecl->hasNonTrivialDestructor());
    classif.isReference = varDecl->getType()->isLValueReferenceType();
    classif.isConst = qualType.isConstQualified();

    if (varDecl->getType()->isRValueReferenceType()) // && ref, nothing to do here
        return true;

    if (classif.isConst && !classif.isReference) {
        classif.passNonTriviallyCopyableByConstRef = classif.isNonTriviallyCopyable;
        if (classif.isBig) {
            classif.passBigTypeByConstRef = true;
        }
    } else if (classif.isConst && classif.isReference && !classif.isNonTriviallyCopyable && !classif.isBig) {
        classif.passSmallTrivialByValue = true;
    } else if (!classif.isConst && !classif.isReference && (classif.isBig || classif.isNonTriviallyCopyable)) {
        if (body && (Utils::containsNonConstMemberCall(body, varDecl) || Utils::isPassedToFunction(body, varDecl, /*byrefonly=*/ true)))
            return true;
        classif.passNonTriviallyCopyableByConstRef = classif.isNonTriviallyCopyable;
        if (classif.isBig) {
            classif.passBigTypeByConstRef = true;
        }
    }

    return true;
}

QualType TypeUtils::unrefQualType(QualType qualType)
{
    const Type *t = qualType.getTypePtrOrNull();
    return (t && t->isReferenceType()) ? t->getPointeeType() : qualType;
}