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Diffstat (limited to 'compilerplugins/clang/unusedfields.cxx')
| -rw-r--r-- | compilerplugins/clang/unusedfields.cxx | 1235 |
1 files changed, 1235 insertions, 0 deletions
diff --git a/compilerplugins/clang/unusedfields.cxx b/compilerplugins/clang/unusedfields.cxx new file mode 100644 index 000000000..24045483f --- /dev/null +++ b/compilerplugins/clang/unusedfields.cxx @@ -0,0 +1,1235 @@ +/* -*- 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/. + */ + +#if !defined _WIN32 //TODO, #include <sys/file.h> + +#include <cassert> +#include <string> +#include <iostream> +#include <fstream> +#include <unordered_set> +#include <vector> +#include <algorithm> +#include <sys/file.h> +#include <unistd.h> + +#include "config_clang.h" + +#include "plugin.hxx" +#include "compat.hxx" +#include "check.hxx" + +#include "clang/AST/ParentMapContext.h" + +/** +This performs two analyses: + (1) look for unused fields + (2) look for fields that are write-only + +We dmp a list of calls to methods, and a list of field definitions. +Then we will post-process the 2 lists and find the set of unused methods. + +Be warned that it produces around 5G of log file. + +The process goes something like this: + $ make check + $ make FORCE_COMPILE=all COMPILER_PLUGIN_TOOL='unusedfields' check + $ ./compilerplugins/clang/unusedfields.py + +and then + $ for dir in *; do make FORCE_COMPILE=all UPDATE_FILES=$dir COMPILER_PLUGIN_TOOL='unusedfieldsremove' $dir; done +to auto-remove the method declarations + +Note that the actual process may involve a fair amount of undoing, hand editing, and general messing around +to get it to work :-) + +*/ + +namespace { + +struct MyFieldInfo +{ + const RecordDecl* parentRecord; + std::string parentClass; + std::string fieldName; + std::string fieldType; + std::string sourceLocation; + std::string access; +}; +bool operator < (const MyFieldInfo &lhs, const MyFieldInfo &rhs) +{ + return std::tie(lhs.parentClass, lhs.fieldName) + < std::tie(rhs.parentClass, rhs.fieldName); +} + + +// try to limit the voluminous output a little +static std::set<MyFieldInfo> touchedFromInsideSet; +static std::set<MyFieldInfo> touchedFromOutsideSet; +static std::set<MyFieldInfo> touchedFromOutsideConstructorSet; +static std::set<MyFieldInfo> readFromSet; +static std::set<MyFieldInfo> writeToSet; +static std::set<MyFieldInfo> definitionSet; + +/** + * Wrap the different kinds of callable and callee objects in the clang AST so I can define methods that handle everything. + */ +class CallerWrapper +{ + const CallExpr * m_callExpr; + const CXXConstructExpr * m_cxxConstructExpr; +public: + CallerWrapper(const CallExpr * callExpr) : m_callExpr(callExpr), m_cxxConstructExpr(nullptr) {} + CallerWrapper(const CXXConstructExpr * cxxConstructExpr) : m_callExpr(nullptr), m_cxxConstructExpr(cxxConstructExpr) {} + unsigned getNumArgs () const + { return m_callExpr ? m_callExpr->getNumArgs() : m_cxxConstructExpr->getNumArgs(); } + const Expr * getArg (unsigned i) const + { return m_callExpr ? m_callExpr->getArg(i) : m_cxxConstructExpr->getArg(i); } +}; +class CalleeWrapper +{ + const FunctionDecl * m_calleeFunctionDecl = nullptr; + const CXXConstructorDecl * m_cxxConstructorDecl = nullptr; + const FunctionProtoType * m_functionPrototype = nullptr; +public: + explicit CalleeWrapper(const FunctionDecl * calleeFunctionDecl) : m_calleeFunctionDecl(calleeFunctionDecl) {} + explicit CalleeWrapper(const CXXConstructExpr * cxxConstructExpr) : m_cxxConstructorDecl(cxxConstructExpr->getConstructor()) {} + explicit CalleeWrapper(const FunctionProtoType * functionPrototype) : m_functionPrototype(functionPrototype) {} + unsigned getNumParams() const + { + if (m_calleeFunctionDecl) + return m_calleeFunctionDecl->getNumParams(); + else if (m_cxxConstructorDecl) + return m_cxxConstructorDecl->getNumParams(); + else if (m_functionPrototype->param_type_begin() == m_functionPrototype->param_type_end()) + // FunctionProtoType will assert if we call getParamTypes() and it has no params + return 0; + else + return m_functionPrototype->getParamTypes().size(); + } + const QualType getParamType(unsigned i) const + { + if (m_calleeFunctionDecl) + return m_calleeFunctionDecl->getParamDecl(i)->getType(); + else if (m_cxxConstructorDecl) + return m_cxxConstructorDecl->getParamDecl(i)->getType(); + else + return m_functionPrototype->getParamTypes()[i]; + } + std::string getNameAsString() const + { + if (m_calleeFunctionDecl) + return m_calleeFunctionDecl->getNameAsString(); + else if (m_cxxConstructorDecl) + return m_cxxConstructorDecl->getNameAsString(); + else + return ""; + } + CXXMethodDecl const * getAsCXXMethodDecl() const + { + if (m_calleeFunctionDecl) + return dyn_cast<CXXMethodDecl>(m_calleeFunctionDecl); + return nullptr; + } +}; + +class UnusedFields: + public loplugin::FilteringPlugin<UnusedFields> +{ +public: + explicit UnusedFields(loplugin::InstantiationData const & data): + FilteringPlugin(data) {} + + virtual void run() override; + + bool shouldVisitTemplateInstantiations () const { return true; } + bool shouldVisitImplicitCode() const { return true; } + + bool VisitFieldDecl( const FieldDecl* ); + bool VisitMemberExpr( const MemberExpr* ); + bool VisitDeclRefExpr( const DeclRefExpr* ); + bool VisitCXXConstructorDecl( const CXXConstructorDecl* ); + bool VisitInitListExpr( const InitListExpr* ); + bool TraverseCXXConstructorDecl( CXXConstructorDecl* ); + bool TraverseCXXMethodDecl( CXXMethodDecl* ); + bool TraverseFunctionDecl( FunctionDecl* ); + bool TraverseIfStmt( IfStmt* ); + +private: + MyFieldInfo niceName(const FieldDecl*); + bool ignoreLocation(SourceLocation loc); + bool checkIgnoreLocation(SourceLocation loc); + void checkTouchedFromOutside(const FieldDecl* fieldDecl, const Expr* memberExpr); + void checkIfReadFrom(const FieldDecl* fieldDecl, const Expr* memberExpr); + void checkIfWrittenTo(const FieldDecl* fieldDecl, const Expr* memberExpr); + bool isSomeKindOfZero(const Expr* arg); + bool checkForWriteWhenUsingCollectionType(const CXXMethodDecl * calleeMethodDecl); + bool IsPassedByNonConst(const FieldDecl* fieldDecl, const Stmt * child, CallerWrapper callExpr, + CalleeWrapper calleeFunctionDecl); + llvm::Optional<CalleeWrapper> getCallee(CallExpr const *); + + RecordDecl * insideMoveOrCopyOrCloneDeclParent = nullptr; + RecordDecl * insideStreamOutputOperator = nullptr; + // For reasons I do not understand, parentFunctionDecl() is not reliable, so + // we store the parent function on the way down the AST. + FunctionDecl * insideFunctionDecl = nullptr; + std::vector<FieldDecl const *> insideConditionalCheckOfMemberSet; +}; + +void UnusedFields::run() +{ + TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); + + if (!isUnitTestMode()) + { + // dump all our output in one write call - this is to try and limit IO "crosstalk" between multiple processes + // writing to the same logfile + std::string output; + for (const MyFieldInfo & s : touchedFromInsideSet) + output += "inside:\t" + s.parentClass + "\t" + s.fieldName + "\n"; + for (const MyFieldInfo & s : touchedFromOutsideSet) + output += "outside:\t" + s.parentClass + "\t" + s.fieldName + "\n"; + for (const MyFieldInfo & s : touchedFromOutsideConstructorSet) + output += "outside-constructor:\t" + s.parentClass + "\t" + s.fieldName + "\n"; + for (const MyFieldInfo & s : readFromSet) + output += "read:\t" + s.parentClass + "\t" + s.fieldName + "\n"; + for (const MyFieldInfo & s : writeToSet) + output += "write:\t" + s.parentClass + "\t" + s.fieldName + "\n"; + for (const MyFieldInfo & s : definitionSet) + output += "definition:\t" + s.access + "\t" + s.parentClass + "\t" + s.fieldName + "\t" + s.fieldType + "\t" + s.sourceLocation + "\n"; + std::ofstream myfile; + myfile.open( WORKDIR "/loplugin.unusedfields.log", std::ios::app | std::ios::out); + myfile << output; + myfile.close(); + } + else + { + for (const MyFieldInfo & s : readFromSet) + report( + DiagnosticsEngine::Warning, + "read %0", + s.parentRecord->getBeginLoc()) + << s.fieldName; + for (const MyFieldInfo & s : writeToSet) + report( + DiagnosticsEngine::Warning, + "write %0", + s.parentRecord->getBeginLoc()) + << s.fieldName; + for (const MyFieldInfo & s : touchedFromOutsideConstructorSet) + report( + DiagnosticsEngine::Warning, + "outside-constructor %0", + s.parentRecord->getBeginLoc()) + << s.fieldName; + for (const MyFieldInfo & s : touchedFromOutsideSet) + report( + DiagnosticsEngine::Warning, + "outside %0", + s.parentRecord->getBeginLoc()) + << s.fieldName; + } +} + + +MyFieldInfo UnusedFields::niceName(const FieldDecl* fieldDecl) +{ + MyFieldInfo aInfo; + + const RecordDecl* recordDecl = fieldDecl->getParent(); + + if (const CXXRecordDecl* cxxRecordDecl = dyn_cast<CXXRecordDecl>(recordDecl)) + { + if (cxxRecordDecl->getTemplateInstantiationPattern()) + cxxRecordDecl = cxxRecordDecl->getTemplateInstantiationPattern(); + aInfo.parentRecord = cxxRecordDecl; + aInfo.parentClass = cxxRecordDecl->getQualifiedNameAsString(); + } + else + { + aInfo.parentRecord = recordDecl; + aInfo.parentClass = recordDecl->getQualifiedNameAsString(); + } + + aInfo.fieldName = fieldDecl->getNameAsString(); + // sometimes the name (if it's an anonymous thing) contains the full path of the build folder, which we don't need + size_t idx = aInfo.fieldName.find(SRCDIR); + if (idx != std::string::npos) { + aInfo.fieldName = aInfo.fieldName.replace(idx, strlen(SRCDIR), ""); + } + aInfo.fieldType = fieldDecl->getType().getAsString(); + + SourceLocation expansionLoc = compiler.getSourceManager().getExpansionLoc( fieldDecl->getLocation() ); + StringRef name = getFilenameOfLocation(expansionLoc); + aInfo.sourceLocation = std::string(name.substr(strlen(SRCDIR)+1)) + ":" + std::to_string(compiler.getSourceManager().getSpellingLineNumber(expansionLoc)); + loplugin::normalizeDotDotInFilePath(aInfo.sourceLocation); + + switch (fieldDecl->getAccess()) + { + case AS_public: aInfo.access = "public"; break; + case AS_private: aInfo.access = "private"; break; + case AS_protected: aInfo.access = "protected"; break; + default: aInfo.access = "unknown"; break; + } + + return aInfo; +} + +/** + * Our need to see everything conflicts with the PCH code in pluginhandler::ignoreLocation, + * so we have to do this ourselves. + */ +bool UnusedFields::ignoreLocation(SourceLocation loc) +{ + static std::unordered_map<SourceLocation, bool> checkedMap; + auto it = checkedMap.find(loc); + if (it != checkedMap.end()) + return it->second; + bool ignore = checkIgnoreLocation(loc); + checkedMap.emplace(loc, ignore); + return ignore; +} + +bool UnusedFields::checkIgnoreLocation(SourceLocation loc) +{ + // simplified form of the code in PluginHandler::checkIgnoreLocation + SourceLocation expansionLoc = compiler.getSourceManager().getExpansionLoc( loc ); + if( compiler.getSourceManager().isInSystemHeader( expansionLoc )) + return true; + PresumedLoc presumedLoc = compiler.getSourceManager().getPresumedLoc( expansionLoc ); + if( presumedLoc.isInvalid()) + return true; + const char* bufferName = presumedLoc.getFilename(); + if (bufferName == NULL + || loplugin::hasPathnamePrefix(bufferName, SRCDIR "/external/") + || loplugin::hasPathnamePrefix(bufferName, WORKDIR "/")) + return true; + if( loplugin::hasPathnamePrefix(bufferName, BUILDDIR "/") + || loplugin::hasPathnamePrefix(bufferName, SRCDIR "/") ) + return false; // ok + return true; +} + + +bool UnusedFields::VisitFieldDecl( const FieldDecl* fieldDecl ) +{ + fieldDecl = fieldDecl->getCanonicalDecl(); + if (ignoreLocation( fieldDecl->getBeginLoc() )) { + return true; + } + // ignore stuff that forms part of the stable URE interface + if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(fieldDecl->getLocation()))) { + return true; + } + + if (fieldDecl->getInClassInitializer() && !isSomeKindOfZero(fieldDecl->getInClassInitializer())) { + writeToSet.insert(niceName(fieldDecl)); + } + + definitionSet.insert(niceName(fieldDecl)); + return true; +} + +/** + Does the expression being used to initialise a field value evaluate to + the same as a default value? + */ +bool UnusedFields::isSomeKindOfZero(const Expr* arg) +{ + assert(arg); + arg = arg->IgnoreParenCasts(); + if (isa<CXXDefaultArgExpr>(arg)) { + arg = dyn_cast<CXXDefaultArgExpr>(arg)->getExpr(); + } + arg = arg->IgnoreParenCasts(); + // ignore this, it seems to trigger an infinite recursion + if (isa<UnaryExprOrTypeTraitExpr>(arg)) { + return false; + } + if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(arg)) { + return cxxConstructExpr->getConstructor()->isDefaultConstructor(); + } + APSInt x1; + if (compat::EvaluateAsInt(arg, x1, compiler.getASTContext())) + { + return x1 == 0; + } + if (isa<CXXNullPtrLiteralExpr>(arg)) { + return true; + } + if (isa<MaterializeTemporaryExpr>(arg)) + { + const CXXBindTemporaryExpr* strippedArg = dyn_cast_or_null<CXXBindTemporaryExpr>(arg->IgnoreParenCasts()); + if (strippedArg) + { + auto temp = dyn_cast<CXXTemporaryObjectExpr>(strippedArg->getSubExpr()); + if (temp->getNumArgs() == 0) + { + if (loplugin::TypeCheck(temp->getType()).Class("OUString").Namespace("rtl").GlobalNamespace()) { + return true; + } + if (loplugin::TypeCheck(temp->getType()).Class("OString").Namespace("rtl").GlobalNamespace()) { + return true; + } + return false; + } + } + } + + // Get the expression contents. + // This helps us find params which are always initialised with something like "OUString()". + SourceManager& SM = compiler.getSourceManager(); + SourceLocation startLoc = arg->getBeginLoc(); + SourceLocation endLoc = arg->getEndLoc(); + const char *p1 = SM.getCharacterData( startLoc ); + const char *p2 = SM.getCharacterData( endLoc ); + if (!p1 || !p2 || (p2 - p1) < 0 || (p2 - p1) > 40) { + return false; + } + unsigned n = Lexer::MeasureTokenLength( endLoc, SM, compiler.getLangOpts()); + std::string s( p1, p2 - p1 + n); + // strip linefeed and tab characters so they don't interfere with the parsing of the log file + std::replace( s.begin(), s.end(), '\r', ' '); + std::replace( s.begin(), s.end(), '\n', ' '); + std::replace( s.begin(), s.end(), '\t', ' '); + + // now normalize the value. For some params, like OUString, we can pass it as OUString() or "" and they are the same thing + if (s == "OUString()") + return true; + else if (s == "OString()") + return true; + return false; +} + +static char easytolower(char in) +{ + if (in<='Z' && in>='A') + return in-('Z'-'z'); + return in; +} + +bool startswith(const std::string& rStr, const char* pSubStr) +{ + return rStr.compare(0, strlen(pSubStr), pSubStr) == 0; +} + +bool UnusedFields::TraverseCXXConstructorDecl(CXXConstructorDecl* cxxConstructorDecl) +{ + auto copy = insideMoveOrCopyOrCloneDeclParent; + if (!ignoreLocation(cxxConstructorDecl->getBeginLoc()) && cxxConstructorDecl->isThisDeclarationADefinition()) + { + if (cxxConstructorDecl->isCopyOrMoveConstructor()) + insideMoveOrCopyOrCloneDeclParent = cxxConstructorDecl->getParent(); + } + bool ret = RecursiveASTVisitor::TraverseCXXConstructorDecl(cxxConstructorDecl); + insideMoveOrCopyOrCloneDeclParent = copy; + return ret; +} + +bool UnusedFields::TraverseCXXMethodDecl(CXXMethodDecl* cxxMethodDecl) +{ + auto copy1 = insideMoveOrCopyOrCloneDeclParent; + auto copy2 = insideFunctionDecl; + if (!ignoreLocation(cxxMethodDecl->getBeginLoc()) && cxxMethodDecl->isThisDeclarationADefinition()) + { + if (cxxMethodDecl->isCopyAssignmentOperator() + || cxxMethodDecl->isMoveAssignmentOperator() + || (cxxMethodDecl->getIdentifier() + && (cxxMethodDecl->getName().startswith("Clone") + || cxxMethodDecl->getName().startswith("clone") + || cxxMethodDecl->getName().startswith("createClone")))) + insideMoveOrCopyOrCloneDeclParent = cxxMethodDecl->getParent(); + // these are similar in that they tend to simply enumerate all the fields of an object without putting + // them to some useful purpose + auto op = cxxMethodDecl->getOverloadedOperator(); + if (op == OO_EqualEqual || op == OO_ExclaimEqual) + insideMoveOrCopyOrCloneDeclParent = cxxMethodDecl->getParent(); + } + insideFunctionDecl = cxxMethodDecl; + bool ret = RecursiveASTVisitor::TraverseCXXMethodDecl(cxxMethodDecl); + insideMoveOrCopyOrCloneDeclParent = copy1; + insideFunctionDecl = copy2; + return ret; +} + +bool UnusedFields::TraverseFunctionDecl(FunctionDecl* functionDecl) +{ + auto copy1 = insideStreamOutputOperator; + auto copy2 = insideFunctionDecl; + auto copy3 = insideMoveOrCopyOrCloneDeclParent; + if (functionDecl->getLocation().isValid() && !ignoreLocation(functionDecl->getBeginLoc()) && functionDecl->isThisDeclarationADefinition()) + { + auto op = functionDecl->getOverloadedOperator(); + if (op == OO_LessLess + && functionDecl->getNumParams() == 2) + { + QualType qt = functionDecl->getParamDecl(1)->getType(); + insideStreamOutputOperator = qt.getNonReferenceType().getUnqualifiedType()->getAsCXXRecordDecl(); + } + // these are similar in that they tend to simply enumerate all the fields of an object without putting + // them to some useful purpose + if (op == OO_EqualEqual || op == OO_ExclaimEqual) + { + QualType qt = functionDecl->getParamDecl(1)->getType(); + insideMoveOrCopyOrCloneDeclParent = qt.getNonReferenceType().getUnqualifiedType()->getAsCXXRecordDecl(); + } + } + insideFunctionDecl = functionDecl; + bool ret = RecursiveASTVisitor::TraverseFunctionDecl(functionDecl); + insideStreamOutputOperator = copy1; + insideFunctionDecl = copy2; + insideMoveOrCopyOrCloneDeclParent = copy3; + return ret; +} + +bool UnusedFields::TraverseIfStmt(IfStmt* ifStmt) +{ + FieldDecl const * memberFieldDecl = nullptr; + Expr const * cond = ifStmt->getCond()->IgnoreParenImpCasts(); + + if (auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(cond)) + { + if (auto cxxConvert = dyn_cast_or_null<CXXConversionDecl>(memberCallExpr->getMethodDecl())) + { + if (cxxConvert->getConversionType()->isBooleanType()) + if (auto memberExpr = dyn_cast<MemberExpr>(memberCallExpr->getImplicitObjectArgument()->IgnoreParenImpCasts())) + if ((memberFieldDecl = dyn_cast<FieldDecl>(memberExpr->getMemberDecl()))) + insideConditionalCheckOfMemberSet.push_back(memberFieldDecl); + } + else if (auto cxxMethod = memberCallExpr->getMethodDecl()) + { + if (cxxMethod->getIdentifier() && cxxMethod->getName() == "get" && memberCallExpr->getNumArgs()==0) + if (auto memberExpr = dyn_cast<MemberExpr>(memberCallExpr->getImplicitObjectArgument()->IgnoreParenImpCasts())) + if ((memberFieldDecl = dyn_cast<FieldDecl>(memberExpr->getMemberDecl()))) + insideConditionalCheckOfMemberSet.push_back(memberFieldDecl); + } + } + else if (auto memberExpr = dyn_cast<MemberExpr>(cond)) + { + if ((memberFieldDecl = dyn_cast<FieldDecl>(memberExpr->getMemberDecl()))) + insideConditionalCheckOfMemberSet.push_back(memberFieldDecl); + } + + bool ret = RecursiveASTVisitor::TraverseIfStmt(ifStmt); + if (memberFieldDecl) + insideConditionalCheckOfMemberSet.pop_back(); + return ret; +} + +bool UnusedFields::VisitMemberExpr( const MemberExpr* memberExpr ) +{ + const ValueDecl* decl = memberExpr->getMemberDecl(); + const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(decl); + if (!fieldDecl) { + return true; + } + fieldDecl = fieldDecl->getCanonicalDecl(); + if (ignoreLocation(fieldDecl->getBeginLoc())) { + return true; + } + // ignore stuff that forms part of the stable URE interface + if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(fieldDecl->getLocation()))) { + return true; + } + + checkTouchedFromOutside(fieldDecl, memberExpr); + + checkIfReadFrom(fieldDecl, memberExpr); + + checkIfWrittenTo(fieldDecl, memberExpr); + + return true; +} + +void UnusedFields::checkIfReadFrom(const FieldDecl* fieldDecl, const Expr* memberExpr) +{ + if (insideMoveOrCopyOrCloneDeclParent || insideStreamOutputOperator) + { + RecordDecl const * cxxRecordDecl1 = fieldDecl->getParent(); + // we don't care about reads from a field when inside the copy/move constructor/operator= for that field + if (cxxRecordDecl1 && (cxxRecordDecl1 == insideMoveOrCopyOrCloneDeclParent)) + return; + // we don't care about reads when the field is being used in an output operator, this is normally + // debug stuff + if (cxxRecordDecl1 && (cxxRecordDecl1 == insideStreamOutputOperator)) + return; + } + + auto parentsRange = compiler.getASTContext().getParents(*memberExpr); + const Stmt* child = memberExpr; + const Stmt* parent = parentsRange.begin() == parentsRange.end() ? nullptr : parentsRange.begin()->get<Stmt>(); + // walk up the tree until we find something interesting + bool bPotentiallyReadFrom = false; + bool bDump = false; + auto walkUp = [&]() { + child = parent; + auto parentsRange = compiler.getASTContext().getParents(*parent); + parent = parentsRange.begin() == parentsRange.end() ? nullptr : parentsRange.begin()->get<Stmt>(); + }; + do + { + if (!parent) + { + // check if we're inside a CXXCtorInitializer or a VarDecl + auto parentsRange = compiler.getASTContext().getParents(*child); + if ( parentsRange.begin() != parentsRange.end()) + { + const Decl* decl = parentsRange.begin()->get<Decl>(); + if (decl && (isa<CXXConstructorDecl>(decl) || isa<VarDecl>(decl))) + bPotentiallyReadFrom = true; + } + if (!bPotentiallyReadFrom) + return; + break; + } + if (isa<CXXReinterpretCastExpr>(parent)) + { + // once we see one of these, there is not much useful we can know + bPotentiallyReadFrom = true; + break; + } + else if (isa<CastExpr>(parent) || isa<MemberExpr>(parent) || isa<ParenExpr>(parent) || isa<ParenListExpr>(parent) + || isa<ArrayInitLoopExpr>(parent) || isa<ExprWithCleanups>(parent)) + { + walkUp(); + } + else if (auto unaryOperator = dyn_cast<UnaryOperator>(parent)) + { + UnaryOperator::Opcode op = unaryOperator->getOpcode(); + if (memberExpr->getType()->isArrayType() && op == UO_Deref) + { + // ignore, deref'ing an array does not count as a read + } + else if (op == UO_AddrOf || op == UO_Deref + || op == UO_Plus || op == UO_Minus + || op == UO_Not || op == UO_LNot) + { + bPotentiallyReadFrom = true; + break; + } + /* The following are technically reads, but from a code-sense they're more of a write/modify, so + ignore them to find interesting fields that only modified, not usefully read: + UO_PreInc / UO_PostInc / UO_PreDec / UO_PostDec + But we still walk up in case the result of the expression is used in a read sense. + */ + walkUp(); + } + else if (auto caseStmt = dyn_cast<CaseStmt>(parent)) + { + bPotentiallyReadFrom = caseStmt->getLHS() == child || caseStmt->getRHS() == child; + break; + } + else if (auto ifStmt = dyn_cast<IfStmt>(parent)) + { + bPotentiallyReadFrom = ifStmt->getCond() == child; + break; + } + else if (auto doStmt = dyn_cast<DoStmt>(parent)) + { + bPotentiallyReadFrom = doStmt->getCond() == child; + break; + } + else if (auto arraySubscriptExpr = dyn_cast<ArraySubscriptExpr>(parent)) + { + if (arraySubscriptExpr->getIdx() == child) + { + bPotentiallyReadFrom = true; + break; + } + walkUp(); + } + else if (auto binaryOp = dyn_cast<BinaryOperator>(parent)) + { + BinaryOperator::Opcode op = binaryOp->getOpcode(); + const bool assignmentOp = op == BO_Assign || op == BO_MulAssign + || op == BO_DivAssign || op == BO_RemAssign || op == BO_AddAssign + || op == BO_SubAssign || op == BO_ShlAssign || op == BO_ShrAssign + || op == BO_AndAssign || op == BO_XorAssign || op == BO_OrAssign; + if (binaryOp->getLHS() == child && assignmentOp) + break; + else + { + bPotentiallyReadFrom = true; + break; + } + } + else if (auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(parent)) + { + auto op = operatorCallExpr->getOperator(); + const bool assignmentOp = op == OO_Equal || op == OO_StarEqual || + op == OO_SlashEqual || op == OO_PercentEqual || + op == OO_PlusEqual || op == OO_MinusEqual || + op == OO_LessLessEqual || + op == OO_AmpEqual || op == OO_CaretEqual || + op == OO_PipeEqual; + if (operatorCallExpr->getArg(0) == child && assignmentOp) + break; + else if (op == OO_GreaterGreaterEqual && operatorCallExpr->getArg(1) == child) + break; // this is a write-only call + else + { + bPotentiallyReadFrom = true; + break; + } + } + else if (auto cxxMemberCallExpr = dyn_cast<CXXMemberCallExpr>(parent)) + { + bool bWriteOnlyCall = false; + const CXXMethodDecl * callee = cxxMemberCallExpr->getMethodDecl(); + if (callee) + { + const Expr* tmp = dyn_cast<Expr>(child); + if (tmp->isBoundMemberFunction(compiler.getASTContext())) { + tmp = dyn_cast<MemberExpr>(tmp)->getBase(); + } + if (cxxMemberCallExpr->getImplicitObjectArgument() == tmp) + { + // FIXME perhaps a better solution here would be some kind of SAL_PARAM_WRITEONLY attribute + // which we could scatter around. + std::string name = callee->getNameAsString(); + std::transform(name.begin(), name.end(), name.begin(), easytolower); + if (startswith(name, "emplace") || name == "insert" + || name == "erase" || name == "remove" || name == "remove_if" || name == "sort" + || name == "push_back" || name == "pop_back" + || name == "push_front" || name == "pop_front" + || name == "reserve" || name == "resize" || name == "reset" + || name == "clear" || name == "fill") + // write-only modifications to collections + bWriteOnlyCall = true; + else if (name == "dispose" || name == "disposeAndClear" || name == "swap") + // we're abusing the write-only analysis here to look for fields which don't have anything useful + // being done to them, so we're ignoring things like std::vector::clear, std::vector::swap, + // and VclPtr::disposeAndClear + bWriteOnlyCall = true; + } + } + if (!bWriteOnlyCall) + bPotentiallyReadFrom = true; + break; + } + else if (auto callExpr = dyn_cast<CallExpr>(parent)) + { + bool bWriteOnlyCall = false; + // check for calls to ReadXXX(foo) type methods, where foo is write-only + auto callee = getCallee(callExpr); + if (callee) + { + // FIXME perhaps a better solution here would be some kind of SAL_PARAM_WRITEONLY attribute + // which we could scatter around. + std::string name = callee->getNameAsString(); + std::transform(name.begin(), name.end(), name.begin(), easytolower); + if (startswith(name, "read")) + // this is a write-only call + bWriteOnlyCall = true; + } + if (!bWriteOnlyCall) + bPotentiallyReadFrom = true; + break; + } + else if (isa<ReturnStmt>(parent) + || isa<CXXConstructExpr>(parent) + || isa<ConditionalOperator>(parent) + || isa<SwitchStmt>(parent) + || isa<DeclStmt>(parent) + || isa<WhileStmt>(parent) + || isa<CXXNewExpr>(parent) + || isa<ForStmt>(parent) + || isa<InitListExpr>(parent) + || isa<CXXDependentScopeMemberExpr>(parent) + || isa<UnresolvedMemberExpr>(parent) + || isa<MaterializeTemporaryExpr>(parent)) + { + bPotentiallyReadFrom = true; + break; + } + else if (isa<CXXDeleteExpr>(parent) + || isa<UnaryExprOrTypeTraitExpr>(parent) + || isa<CXXUnresolvedConstructExpr>(parent) + || isa<CompoundStmt>(parent) + || isa<LabelStmt>(parent) + || isa<CXXForRangeStmt>(parent) + || isa<CXXTypeidExpr>(parent) + || isa<DefaultStmt>(parent)) + { + break; + } + else + { + bPotentiallyReadFrom = true; + bDump = true; + break; + } + } while (true); + + if (bDump) + { + report( + DiagnosticsEngine::Warning, + "oh dear, what can the matter be?", + memberExpr->getBeginLoc()) + << memberExpr->getSourceRange(); + report( + DiagnosticsEngine::Note, + "parent over here", + parent->getBeginLoc()) + << parent->getSourceRange(); + parent->dump(); + memberExpr->dump(); + } + + MyFieldInfo fieldInfo = niceName(fieldDecl); + if (bPotentiallyReadFrom) + { + readFromSet.insert(fieldInfo); + } +} + +void UnusedFields::checkIfWrittenTo(const FieldDecl* fieldDecl, const Expr* memberExpr) +{ + if (insideMoveOrCopyOrCloneDeclParent) + { + RecordDecl const * cxxRecordDecl1 = fieldDecl->getParent(); + // we don't care about writes to a field when inside the copy/move constructor/operator= for that field + if (cxxRecordDecl1 && (cxxRecordDecl1 == insideMoveOrCopyOrCloneDeclParent)) + { + return; + } + } + + // if we're inside a block that looks like + // if (fieldDecl) + // ... + // then writes to this field don't matter, because unless we find another write to this field, this field is dead + if (std::find(insideConditionalCheckOfMemberSet.begin(), insideConditionalCheckOfMemberSet.end(), fieldDecl) != insideConditionalCheckOfMemberSet.end()) + return; + + auto parentsRange = compiler.getASTContext().getParents(*memberExpr); + const Stmt* child = memberExpr; + const Stmt* parent = parentsRange.begin() == parentsRange.end() ? nullptr : parentsRange.begin()->get<Stmt>(); + // walk up the tree until we find something interesting + bool bPotentiallyWrittenTo = false; + bool bDump = false; + auto walkUp = [&]() { + child = parent; + auto parentsRange = compiler.getASTContext().getParents(*parent); + parent = parentsRange.begin() == parentsRange.end() ? nullptr : parentsRange.begin()->get<Stmt>(); + }; + do + { + if (!parent) + { + // check if we have an expression like + // int& r = m_field; + auto parentsRange = compiler.getASTContext().getParents(*child); + if (parentsRange.begin() != parentsRange.end()) + { + auto varDecl = dyn_cast_or_null<VarDecl>(parentsRange.begin()->get<Decl>()); + // The isImplicit() call is to avoid triggering when we see the vardecl which is part of a for-range statement, + // which is of type 'T&&' and also an l-value-ref ? + if (varDecl && !varDecl->isImplicit() && loplugin::TypeCheck(varDecl->getType()).LvalueReference().NonConst()) + { + bPotentiallyWrittenTo = true; + } + } + break; + } + if (isa<CXXReinterpretCastExpr>(parent)) + { + // once we see one of these, there is not much useful we can know + bPotentiallyWrittenTo = true; + break; + } + else if (isa<CastExpr>(parent) || isa<MemberExpr>(parent) || isa<ParenExpr>(parent) || isa<ParenListExpr>(parent) + || isa<ArrayInitLoopExpr>(parent) || isa<ExprWithCleanups>(parent)) + { + walkUp(); + } + else if (auto unaryOperator = dyn_cast<UnaryOperator>(parent)) + { + UnaryOperator::Opcode op = unaryOperator->getOpcode(); + if (op == UO_AddrOf || op == UO_PostInc || op == UO_PostDec || op == UO_PreInc || op == UO_PreDec) + { + bPotentiallyWrittenTo = true; + } + break; + } + else if (auto arraySubscriptExpr = dyn_cast<ArraySubscriptExpr>(parent)) + { + if (arraySubscriptExpr->getIdx() == child) + break; + walkUp(); + } + else if (auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(parent)) + { + auto callee = getCallee(operatorCallExpr); + if (callee) + { + // if calling a non-const operator on the field + auto calleeMethodDecl = callee->getAsCXXMethodDecl(); + if (calleeMethodDecl && operatorCallExpr->getArg(0) == child) + { + if (!calleeMethodDecl->isConst()) + bPotentiallyWrittenTo = checkForWriteWhenUsingCollectionType(calleeMethodDecl); + } + else if (IsPassedByNonConst(fieldDecl, child, operatorCallExpr, *callee)) + { + bPotentiallyWrittenTo = true; + } + } + else + bPotentiallyWrittenTo = true; // conservative, could improve + break; + } + else if (auto cxxMemberCallExpr = dyn_cast<CXXMemberCallExpr>(parent)) + { + const CXXMethodDecl * calleeMethodDecl = cxxMemberCallExpr->getMethodDecl(); + if (calleeMethodDecl) + { + // if calling a non-const method on the field + const Expr* tmp = dyn_cast<Expr>(child); + if (tmp->isBoundMemberFunction(compiler.getASTContext())) { + tmp = dyn_cast<MemberExpr>(tmp)->getBase(); + } + if (cxxMemberCallExpr->getImplicitObjectArgument() == tmp) + { + if (!calleeMethodDecl->isConst()) + bPotentiallyWrittenTo = checkForWriteWhenUsingCollectionType(calleeMethodDecl); + break; + } + else if (IsPassedByNonConst(fieldDecl, child, cxxMemberCallExpr, CalleeWrapper(calleeMethodDecl))) + bPotentiallyWrittenTo = true; + } + else + bPotentiallyWrittenTo = true; // can happen in templates + break; + } + else if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(parent)) + { + if (IsPassedByNonConst(fieldDecl, child, cxxConstructExpr, CalleeWrapper(cxxConstructExpr))) + bPotentiallyWrittenTo = true; + break; + } + else if (auto callExpr = dyn_cast<CallExpr>(parent)) + { + auto callee = getCallee(callExpr); + if (callee) { + if (IsPassedByNonConst(fieldDecl, child, callExpr, *callee)) + bPotentiallyWrittenTo = true; + } else + bPotentiallyWrittenTo = true; // conservative, could improve + break; + } + else if (auto binaryOp = dyn_cast<BinaryOperator>(parent)) + { + BinaryOperator::Opcode op = binaryOp->getOpcode(); + const bool assignmentOp = op == BO_Assign || op == BO_MulAssign + || op == BO_DivAssign || op == BO_RemAssign || op == BO_AddAssign + || op == BO_SubAssign || op == BO_ShlAssign || op == BO_ShrAssign + || op == BO_AndAssign || op == BO_XorAssign || op == BO_OrAssign; + if (assignmentOp) + { + if (binaryOp->getLHS() == child) + bPotentiallyWrittenTo = true; + else if (loplugin::TypeCheck(binaryOp->getLHS()->getType()).LvalueReference().NonConst()) + // if the LHS is a non-const reference, we could write to the field later on + bPotentiallyWrittenTo = true; + } + break; + } + else if (isa<ReturnStmt>(parent)) + { + if (insideFunctionDecl) + { + auto tc = loplugin::TypeCheck(insideFunctionDecl->getReturnType()); + if (tc.LvalueReference().NonConst()) + bPotentiallyWrittenTo = true; + } + break; + } + else if (isa<ConditionalOperator>(parent) + || isa<SwitchStmt>(parent) + || isa<DeclStmt>(parent) + || isa<WhileStmt>(parent) + || isa<CXXNewExpr>(parent) + || isa<ForStmt>(parent) + || isa<InitListExpr>(parent) + || isa<CXXDependentScopeMemberExpr>(parent) + || isa<UnresolvedMemberExpr>(parent) + || isa<MaterializeTemporaryExpr>(parent) + || isa<IfStmt>(parent) + || isa<DoStmt>(parent) + || isa<CXXDeleteExpr>(parent) + || isa<UnaryExprOrTypeTraitExpr>(parent) + || isa<CXXUnresolvedConstructExpr>(parent) + || isa<CompoundStmt>(parent) + || isa<LabelStmt>(parent) + || isa<CXXForRangeStmt>(parent) + || isa<CXXTypeidExpr>(parent) + || isa<DefaultStmt>(parent)) + { + break; + } + else + { + bPotentiallyWrittenTo = true; + bDump = true; + break; + } + } while (true); + + if (bDump) + { + report( + DiagnosticsEngine::Warning, + "oh dear, what can the matter be? writtenTo=%0", + memberExpr->getBeginLoc()) + << bPotentiallyWrittenTo + << memberExpr->getSourceRange(); + if (parent) + { + report( + DiagnosticsEngine::Note, + "parent over here", + parent->getBeginLoc()) + << parent->getSourceRange(); + parent->dump(); + } + memberExpr->dump(); + fieldDecl->getType()->dump(); + } + + MyFieldInfo fieldInfo = niceName(fieldDecl); + if (bPotentiallyWrittenTo) + { + writeToSet.insert(fieldInfo); + } +} + +// return true if this not a collection type, or if it is a collection type, and we might be writing to it +bool UnusedFields::checkForWriteWhenUsingCollectionType(const CXXMethodDecl * calleeMethodDecl) +{ + auto const tc = loplugin::TypeCheck(calleeMethodDecl->getParent()); + bool listLike = false, setLike = false, mapLike = false, cssSequence = false; + if (tc.Class("deque").StdNamespace() + || tc.Class("list").StdNamespace() + || tc.Class("queue").StdNamespace() + || tc.Class("vector").StdNamespace()) + { + listLike = true; + } + else if (tc.Class("set").StdNamespace() + || tc.Class("unordered_set").StdNamespace()) + { + setLike = true; + } + else if (tc.Class("map").StdNamespace() + || tc.Class("unordered_map").StdNamespace()) + { + mapLike = true; + } + else if (tc.Class("Sequence").Namespace("uno").Namespace("star").Namespace("sun").Namespace("com").GlobalNamespace()) + { + cssSequence = true; + } + else + return true; + + if (calleeMethodDecl->isOverloadedOperator()) + { + auto oo = calleeMethodDecl->getOverloadedOperator(); + if (oo == OO_Equal) + return true; + // This is operator[]. We only care about things that add elements to the collection. + // if nothing modifies the size of the collection, then nothing useful + // is stored in it. + if (listLike) + return false; + return true; + } + + auto name = calleeMethodDecl->getName(); + if (listLike || setLike || mapLike) + { + if (name == "reserve" || name == "shrink_to_fit" || name == "clear" + || name == "erase" || name == "pop_back" || name == "pop_front" + || name == "front" || name == "back" || name == "data" + || name == "remove" || name == "remove_if" + || name == "unique" || name == "sort" + || name == "begin" || name == "end" + || name == "rbegin" || name == "rend" + || name == "at" || name == "find" || name == "equal_range" + || name == "lower_bound" || name == "upper_bound") + return false; + } + if (cssSequence) + { + if (name == "getArray" || name == "begin" || name == "end") + return false; + } + + return true; +} + +bool UnusedFields::IsPassedByNonConst(const FieldDecl* fieldDecl, const Stmt * child, CallerWrapper callExpr, + CalleeWrapper calleeFunctionDecl) +{ + unsigned len = std::min(callExpr.getNumArgs(), + calleeFunctionDecl.getNumParams()); + // if it's an array, passing it by value to a method typically means the + // callee takes a pointer and can modify the array + if (fieldDecl->getType()->isConstantArrayType()) + { + for (unsigned i = 0; i < len; ++i) + if (callExpr.getArg(i) == child) + if (loplugin::TypeCheck(calleeFunctionDecl.getParamType(i)).Pointer().NonConst()) + return true; + } + else + { + for (unsigned i = 0; i < len; ++i) + if (callExpr.getArg(i) == child) + if (loplugin::TypeCheck(calleeFunctionDecl.getParamType(i)).LvalueReference().NonConst()) + return true; + } + return false; +} + +// fields that are assigned via member initialisers do not get visited in VisitDeclRef, so +// have to do it here +bool UnusedFields::VisitCXXConstructorDecl( const CXXConstructorDecl* cxxConstructorDecl ) +{ + if (ignoreLocation( cxxConstructorDecl->getBeginLoc() )) { + return true; + } + // ignore stuff that forms part of the stable URE interface + if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(cxxConstructorDecl->getLocation()))) { + return true; + } + + // templates make EvaluateAsInt crash inside clang + if (cxxConstructorDecl->isDependentContext()) + return true; + + // we don't care about writes to a field when inside the copy/move constructor/operator= for that field + if (insideMoveOrCopyOrCloneDeclParent && cxxConstructorDecl->getParent() == insideMoveOrCopyOrCloneDeclParent) + return true; + + for(auto it = cxxConstructorDecl->init_begin(); it != cxxConstructorDecl->init_end(); ++it) + { + const CXXCtorInitializer* init = *it; + const FieldDecl* fieldDecl = init->getMember(); + if (fieldDecl && init->getInit() && !isSomeKindOfZero(init->getInit())) + { + MyFieldInfo fieldInfo = niceName(fieldDecl); + writeToSet.insert(fieldInfo); + } + } + return true; +} + +// Fields that are assigned via init-list-expr do not get visited in VisitDeclRef, so +// have to do it here. +bool UnusedFields::VisitInitListExpr( const InitListExpr* initListExpr) +{ + if (ignoreLocation( initListExpr->getBeginLoc() )) + return true; + + QualType varType = initListExpr->getType().getDesugaredType(compiler.getASTContext()); + auto recordType = varType->getAs<RecordType>(); + if (!recordType) + return true; + + auto recordDecl = recordType->getDecl(); + for (auto it = recordDecl->field_begin(); it != recordDecl->field_end(); ++it) + { + MyFieldInfo fieldInfo = niceName(*it); + writeToSet.insert(fieldInfo); + } + + return true; +} + +bool UnusedFields::VisitDeclRefExpr( const DeclRefExpr* declRefExpr ) +{ + const Decl* decl = declRefExpr->getDecl(); + const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(decl); + if (!fieldDecl) { + return true; + } + fieldDecl = fieldDecl->getCanonicalDecl(); + if (ignoreLocation(fieldDecl->getBeginLoc())) { + return true; + } + // ignore stuff that forms part of the stable URE interface + if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(fieldDecl->getLocation()))) { + return true; + } + checkTouchedFromOutside(fieldDecl, declRefExpr); + return true; +} + +void UnusedFields::checkTouchedFromOutside(const FieldDecl* fieldDecl, const Expr* memberExpr) { + const FunctionDecl* memberExprParentFunction = getParentFunctionDecl(memberExpr); + const CXXMethodDecl* methodDecl = dyn_cast_or_null<CXXMethodDecl>(memberExprParentFunction); + + MyFieldInfo fieldInfo = niceName(fieldDecl); + + // it's touched from somewhere outside a class + if (!methodDecl) { + touchedFromOutsideSet.insert(fieldInfo); + return; + } + + auto constructorDecl = dyn_cast<CXXConstructorDecl>(methodDecl); + if (methodDecl->isCopyAssignmentOperator() || methodDecl->isMoveAssignmentOperator()) { + // ignore move/copy operator, it's self->self + } else if (constructorDecl && (constructorDecl->isCopyConstructor() || constructorDecl->isMoveConstructor())) { + // ignore move/copy constructor, it's self->self + } else { + if (memberExprParentFunction->getParent() == fieldDecl->getParent()) { + touchedFromInsideSet.insert(fieldInfo); + if (!constructorDecl) + touchedFromOutsideConstructorSet.insert(fieldInfo); + } else { + if (fieldDecl->getName() == "m_pShell") + { + if (memberExprParentFunction) + memberExprParentFunction->dump(); + memberExpr->dump(); + std::cout << "site2" << std::endl; + } + touchedFromOutsideSet.insert(fieldInfo); + } + } +} + +llvm::Optional<CalleeWrapper> UnusedFields::getCallee(CallExpr const * callExpr) +{ + FunctionDecl const * functionDecl = callExpr->getDirectCallee(); + if (functionDecl) + return CalleeWrapper(functionDecl); + + // Extract the functionprototype from a type + clang::Type const * calleeType = callExpr->getCallee()->getType().getTypePtr(); + if (auto pointerType = calleeType->getUnqualifiedDesugaredType()->getAs<clang::PointerType>()) { + if (auto prototype = pointerType->getPointeeType()->getUnqualifiedDesugaredType()->getAs<FunctionProtoType>()) { + return CalleeWrapper(prototype); + } + } + + return llvm::Optional<CalleeWrapper>(); +} + +loplugin::Plugin::Registration< UnusedFields > X("unusedfields", false); + +} + +#endif + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |