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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#include <string>
#include <iostream>
#include "plugin.hxx"
#include "compat.hxx"
#include "clang/AST/CXXInheritance.h"
// Idea from bubli. Check that the index variable in a for loop is able to cover the range
// revealed by the terminating condition.
// If not, we might end up in an endless loop, or just not process certain parts.
namespace
{
class LoopVarTooSmall:
public RecursiveASTVisitor<LoopVarTooSmall>, public loplugin::Plugin
{
public:
explicit LoopVarTooSmall(InstantiationData const & data): Plugin(data) {}
virtual void run() override {
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
}
bool VisitForStmt( const ForStmt* stmt );
private:
StringRef getFilename(SourceLocation loc);
};
StringRef LoopVarTooSmall::getFilename(SourceLocation loc)
{
SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(loc);
StringRef name { compiler.getSourceManager().getFilename(spellingLocation) };
return name;
}
bool LoopVarTooSmall::VisitForStmt( const ForStmt* stmt )
{
if (ignoreLocation( stmt ))
return true;
// ignore sal/ module for now
StringRef aFileName = getFilename(stmt->getLocStart());
if (aFileName.startswith(SRCDIR "/sal/")) {
return true;
}
const Stmt* initStmt = stmt->getInit();
if (!initStmt || !isa<DeclStmt>(initStmt))
return true;
const DeclStmt* declStmt = dyn_cast<DeclStmt>(initStmt);
if (!declStmt->getDeclGroup().isSingleDecl())
return true;
const Decl* decl = declStmt->getSingleDecl();
if (!decl || !isa<VarDecl>(decl))
return true;
const VarDecl* varDecl = dyn_cast<VarDecl>(decl);
QualType qt = varDecl->getType();
if (!qt->isIntegralType(compiler.getASTContext()))
return true;
uint64_t qt1BitWidth = compiler.getASTContext().getTypeSize(qt);
if (!stmt->getCond() || !isa<BinaryOperator>(stmt->getCond()))
return true;
const BinaryOperator* binOp = dyn_cast<BinaryOperator>(stmt->getCond());
if (binOp->getOpcode() != BO_LT && binOp->getOpcode() != BO_LE)
return true;
const Expr* binOpRHS = binOp->getRHS();
// ignore complex expressions for now, promotion rules on conditions like "i < (size()+1)"
// make it hard to guess at a correct type.
if (isa<BinaryOperator>(binOpRHS) || isa<ParenExpr>(binOpRHS))
return true;
if (isa<ImplicitCastExpr>(binOpRHS)) {
const ImplicitCastExpr* castExpr = dyn_cast<ImplicitCastExpr>(binOpRHS);
binOpRHS = castExpr->getSubExpr();
}
QualType qt2 = binOpRHS->getType();
if (!qt2->isIntegralType(compiler.getASTContext()))
return true;
// check for comparison with constants where the compiler just tends to give me the type as "int"
llvm::APSInt aIntResult;
uint64_t qt2BitWidth = compiler.getASTContext().getTypeSize(qt2);
if (binOpRHS->EvaluateAsInt(aIntResult, compiler.getASTContext())) {
if (aIntResult.getSExtValue() > 0 && aIntResult.getSExtValue() < 1<<7) {
qt2BitWidth = 8;
} else if (aIntResult.getSExtValue() > 0 && aIntResult.getSExtValue() < 1<<15) {
qt2BitWidth = 16;
} else if (aIntResult.getSExtValue() > 0 && aIntResult.getSExtValue() < 1L<<31) {
qt2BitWidth = 32;
}
}
if (qt1BitWidth < qt2BitWidth) {
report(
DiagnosticsEngine::Warning,
"loop index type is smaller than length type. " + qt.getAsString() + " < " + qt2.getAsString(),
stmt->getInit()->getLocStart())
<< stmt->getInit()->getSourceRange();
//stmt->getCond()->dump();
}
return true;
}
loplugin::Plugin::Registration< LoopVarTooSmall > X("loopvartoosmall", false);
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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