9c346feb33
...which causes asserts to fire since <https://github.com/llvm/llvm-project/ commit/04323c24a1ac9464471331d9f6499d3cb95d1ccd> "Added an assertion to constant evaluation enty points that prohibits …" Change-Id: Iafbf1cea85d15a38a71275d4cea8303bab500f6a Reviewed-on: https://gerrit.libreoffice.org/72723 Tested-by: Jenkins Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
153 lines
5.4 KiB
C++
153 lines
5.4 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#include <string>
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#include <set>
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#include <iostream>
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#include <fstream>
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#include "plugin.hxx"
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#include "compat.hxx"
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#include "check.hxx"
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/**
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Look for & and operator& expressions where the result is always zero.
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Generally a mistake when people meant to use | or operator|
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*/
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namespace {
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class ExpressionAlwaysZero:
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public loplugin::FilteringPlugin<ExpressionAlwaysZero>
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{
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public:
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explicit ExpressionAlwaysZero(loplugin::InstantiationData const & data): FilteringPlugin(data) {}
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virtual void run() override
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{
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// don't use getMainFileID, it may return "<stdin>"
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std::string fn(handler.getMainFileName());
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loplugin::normalizeDotDotInFilePath(fn);
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// encoding of constant value for binary file format
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if (loplugin::hasPathnamePrefix(fn, SRCDIR "/package/source/zipapi/ZipFile.cxx"))
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return;
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// some auto-generated static data
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if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sal/textenc/tables.cxx"))
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return;
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// nested conditional defines that are not worth cleaning up
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if (loplugin::hasPathnamePrefix(fn, SRCDIR "/opencl/source/openclwrapper.cxx"))
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return;
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// some kind of matrix calculation, the compiler will optimise it out anyway
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if (loplugin::hasPathnamePrefix(fn, SRCDIR "/vcl/source/gdi/bitmap4.cxx"))
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return;
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// code follows a pattern
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if (loplugin::hasPathnamePrefix(fn, SRCDIR "/svx/source/svdraw/svdhdl.cxx"))
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return;
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// looks like some kind of TODO marker
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if (loplugin::hasPathnamePrefix(fn, SRCDIR "/chart2/source/view/main/PropertyMapper.cxx")
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|| loplugin::hasPathnamePrefix(fn, SRCDIR "/sc/source/core/data/formulacell.cxx"))
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return;
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TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
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}
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bool VisitBinaryOperator(BinaryOperator const *);
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bool VisitCXXOperatorCallExpr(CXXOperatorCallExpr const *);
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bool TraverseStaticAssertDecl(StaticAssertDecl *);
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private:
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// note, abusing std::unique_ptr as a std::optional lookalike
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std::unique_ptr<APSInt> getExprValue(const Expr* arg);
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};
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bool ExpressionAlwaysZero::VisitBinaryOperator( BinaryOperator const * binaryOperator )
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{
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if (ignoreLocation(binaryOperator))
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return true;
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if (compat::getBeginLoc(binaryOperator).isMacroID())
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return true;
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auto op = binaryOperator->getOpcode();
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if (!(op == BO_And || op == BO_AndAssign || op == BO_LAnd))
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return true;
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auto lhsValue = getExprValue(binaryOperator->getLHS());
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auto rhsValue = getExprValue(binaryOperator->getRHS());
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if (lhsValue && lhsValue->getExtValue() == 0)
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; // ok
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else if (rhsValue && rhsValue->getExtValue() == 0)
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; // ok
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else if (lhsValue && rhsValue && (lhsValue->getExtValue() & rhsValue->getExtValue()) == 0)
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; // ok
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else
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return true;
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report(
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DiagnosticsEngine::Warning, "expression always evaluates to zero, lhs=%0 rhs=%1",
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compat::getBeginLoc(binaryOperator))
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<< (lhsValue ? lhsValue->toString(10) : "unknown")
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<< (rhsValue ? rhsValue->toString(10) : "unknown")
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<< binaryOperator->getSourceRange();
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return true;
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}
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bool ExpressionAlwaysZero::VisitCXXOperatorCallExpr( CXXOperatorCallExpr const * cxxOperatorCallExpr )
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{
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if (ignoreLocation(cxxOperatorCallExpr))
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return true;
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if (compat::getBeginLoc(cxxOperatorCallExpr).isMacroID())
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return true;
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auto op = cxxOperatorCallExpr->getOperator();
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if ( !(op == OO_Amp || op == OO_AmpEqual || op == OO_AmpAmp))
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return true;
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if (cxxOperatorCallExpr->getNumArgs() != 2)
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return true;
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auto lhsValue = getExprValue(cxxOperatorCallExpr->getArg(0));
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auto rhsValue = getExprValue(cxxOperatorCallExpr->getArg(1));
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if (lhsValue && lhsValue->getExtValue() == 0)
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; // ok
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else if (rhsValue && rhsValue->getExtValue() == 0)
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; // ok
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else if (lhsValue && rhsValue && (lhsValue->getExtValue() & rhsValue->getExtValue()) == 0)
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; // ok
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else
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return true;
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report(
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DiagnosticsEngine::Warning, "expression always evaluates to zero, lhs=%0 rhs=%1",
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compat::getBeginLoc(cxxOperatorCallExpr))
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<< (lhsValue ? lhsValue->toString(10) : "unknown")
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<< (rhsValue ? rhsValue->toString(10) : "unknown")
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<< cxxOperatorCallExpr->getSourceRange();
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return true;
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}
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std::unique_ptr<APSInt> ExpressionAlwaysZero::getExprValue(Expr const * expr)
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{
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expr = expr->IgnoreParenCasts();
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// ignore this, it seems to trigger an infinite recursion
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if (isa<UnaryExprOrTypeTraitExpr>(expr)) {
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return std::unique_ptr<APSInt>();
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}
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APSInt x1;
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if (!expr->isValueDependent() && compat::EvaluateAsInt(expr, x1, compiler.getASTContext()))
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return std::unique_ptr<APSInt>(new APSInt(x1));
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return std::unique_ptr<APSInt>();
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}
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// these will often evaluate to zero harmlessly
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bool ExpressionAlwaysZero::TraverseStaticAssertDecl( StaticAssertDecl * )
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{
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return true;
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}
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loplugin::Plugin::Registration< ExpressionAlwaysZero > X("expressionalwayszero", false);
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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