File indexing completed on 2024-05-12 05:40:59

 /*
     SPDX-FileCopyrightText: 2015 Klarälvdalens Datakonsult AB a KDAB Group company info@kdab.com
     SPDX-FileContributor: Sérgio Martins <sergio.martins@kdab.com>
 
     SPDX-FileCopyrightText: 2015 Sergio Martins <smartins@kde.org>
 
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
 #include "range-loop-detach.h"
 #include "ClazyContext.h"
 #include "FixItUtils.h"
 #include "LoopUtils.h"
 #include "PreProcessorVisitor.h"
 #include "QtUtils.h"
 #include "StmtBodyRange.h"
 #include "TypeUtils.h"
 #include "Utils.h"
 
 #include <clang/AST/Decl.h>
 #include <clang/AST/DeclCXX.h>
 #include <clang/AST/Expr.h>
 #include <clang/AST/Stmt.h>
 #include <clang/AST/StmtCXX.h>
 #include <clang/AST/Type.h>
 #include <llvm/Support/Casting.h>
 
 class ClazyContext;
 
 using namespace clang;
 
 namespace clazy
 {
 /**
  * Returns true if we can prove the container doesn't detach.
  * Returns false otherwise, meaning that you can't conclude anything if false is returned.
  *
  * For true to be returned, all these conditions must verify:
  * - Container is a local variable
  * - It's not passed to any function
  * - It's not assigned to another variable
  */
 bool containerNeverDetaches(const clang::VarDecl *valDecl, StmtBodyRange bodyRange) // clazy:exclude=function-args-by-value
 {
     // This helps for bug 367485
 
     if (!valDecl) {
         return false;
     }
 
     const auto *const context = dyn_cast<FunctionDecl>(valDecl->getDeclContext());
     if (!context) {
         return false;
     }
 
     bodyRange.body = context->getBody();
     if (!bodyRange.body) {
         return false;
     }
 
     if (valDecl->hasInit()) {
         if (const auto *cleanupExpr = dyn_cast<clang::ExprWithCleanups>(valDecl->getInit())) {
             if (const auto *ce = dyn_cast<clang::CXXConstructExpr>(cleanupExpr->getSubExpr())) {
                 if (!ce->isListInitialization() && !ce->isStdInitListInitialization()) {
                     // When initing via copy or move ctor there's possible detachments.
                     return false;
                 }
             } else if (dyn_cast<clang::CXXBindTemporaryExpr>(cleanupExpr->getSubExpr())) {
                 return false;
             }
         }
     }
 
     // TODO1: Being passed to a function as const should be OK
     if (Utils::isPassedToFunction(bodyRange, valDecl, false)) {
         return false;
     }
 
     return true;
 }
 }
 
 RangeLoopDetach::RangeLoopDetach(const std::string &name, ClazyContext *context)
     : CheckBase(name, context, Option_CanIgnoreIncludes)
 {
     context->enablePreprocessorVisitor();
 }
 
 void RangeLoopDetach::VisitStmt(clang::Stmt *stmt)
 {
     if (auto *rangeLoop = dyn_cast<CXXForRangeStmt>(stmt)) {
         processForRangeLoop(rangeLoop);
     }
 }
 
 bool RangeLoopDetach::islvalue(Expr *exp, SourceLocation &endLoc)
 {
     if (isa<DeclRefExpr>(exp)) {
         endLoc = clazy::locForEndOfToken(&m_astContext, exp->getBeginLoc());
         return true;
     }
 
     if (auto *me = dyn_cast<MemberExpr>(exp)) {
         auto *decl = me->getMemberDecl();
         if (!decl || isa<FunctionDecl>(decl)) {
             return false;
         }
 
         endLoc = clazy::locForEndOfToken(&m_astContext, me->getMemberLoc());
         return true;
     }
 
     return false;
 }
 
 void RangeLoopDetach::processForRangeLoop(CXXForRangeStmt *rangeLoop)
 {
     Expr *containerExpr = rangeLoop->getRangeInit();
     if (!containerExpr) {
         return;
     }
 
     QualType qt = containerExpr->getType();
     const Type *t = qt.getTypePtrOrNull();
     if (!t || !t->isRecordType()) {
         return;
     }
 
     if (qt.isConstQualified()) { // const won't detach
         return;
     }
 
     auto loopVariableType = rangeLoop->getLoopVariable()->getType();
     if (!clazy::unrefQualType(loopVariableType).isConstQualified() && loopVariableType->isReferenceType()) {
         return;
     }
 
     CXXRecordDecl *record = t->getAsCXXRecordDecl();
     if (!clazy::isQtCOWIterableClass(Utils::rootBaseClass(record))) {
         return;
     }
 
     StmtBodyRange bodyRange(nullptr, &sm(), rangeLoop->getBeginLoc());
     if (clazy::containerNeverDetaches(clazy::containerDeclForLoop(rangeLoop), bodyRange)) {
         return;
     }
 
     std::vector<FixItHint> fixits;
 
     SourceLocation end;
     if (islvalue(containerExpr, /*by-ref*/ end)) {
         PreProcessorVisitor *preProcessorVisitor = m_context->preprocessorVisitor;
         if (!preProcessorVisitor || preProcessorVisitor->qtVersion() >= 50700) { // qAsConst() was added to 5.7
             clang::SourceRange exprRange = containerExpr->getSourceRange();
             llvm::StringRef exprText = Lexer::getSourceText(CharSourceRange::getTokenRange(exprRange.getBegin(), exprRange.getEnd()), sm(), lo());
             std::string insertion = (lo().CPlusPlus17 ? "std::as_const(" : "qAsConst(") + exprText.str() + ")";
             fixits.push_back(clazy::createReplacement(exprRange, insertion));
         }
     }
 
     auto *typedefType = t->getAs<TypedefType>(); // Typedefs in internal Qt code, like QStringList should not be resolved
     const std::string name = typedefType ? typedefType->getDecl()->getNameAsString() : record->getNameAsString();
     emitWarning(rangeLoop->getBeginLoc(), "c++11 range-loop might detach Qt container (" + name + ')', fixits);
 }