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office-gobmx/compilerplugins/clang/unusedfields.cxx
Stephan Bergmann d1a2b80b9d Bump compiler plugins Clang baseline to 12.0.1 
...as discussed in the mail thread starting at
<https://lists.freedesktop.org/archives/libreoffice/2020-November/086234.html>
"Bump --enable-compiler-plugins Clang baseline?" (and now picked up again at
<https://lists.freedesktop.org/archives/libreoffice/2022-February/088459.html>
"Re: Bump --enable-compiler-plugins Clang baseline?"), and clean up
compilerplugins/clang/ accordingly

Change-Id: I5e81c6fdcc363aeefd6227606225b526fdf7ac16
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129989
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
2022-02-17 21:45:06 +01:00

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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/.
*/
#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: */
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