Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 577 insertions, 0 deletions

diff --git a/compilerplugins/clang/singlevalfields.cxx b/compilerplugins/clang/singlevalfields.cxx
new file mode 100644
index 000000000..df5abcc00
--- /dev/null
+++ b/compilerplugins/clang/singlevalfields.cxx
@@ -0,0 +1,577 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <set>
+
+#include "config_clang.h"
+
+#include "compat.hxx"
+#include "plugin.hxx"
+
+#include "clang/AST/ParentMapContext.h"
+
+/**
+Look for fields that are only ever assigned a single constant value.
+
+We dmp a list of values assigned to fields, and a list of field definitions.
+Then we will post-process the 2 lists and find the set of interesting fields.
+
+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='singlevalfields' check
+  $ ./compilerplugins/clang/singlevalfields.py
+
+Note that the actual process may involve a fair amount of undoing, hand editing, and general messing around
+to get it to work :-)
+
+@TODO we don't spot fields that have been zero-initialised via calloc or rtl_allocateZeroMemory or memset
+@TODO calls to lambdas where a reference to the field is taken
+
+*/
+
+namespace {
+
+struct MyFieldInfo
+{
+    FieldDecl const * fieldDecl;
+    std::string parentClass;
+    std::string fieldName;
+    std::string fieldType;
+    std::string sourceLocation;
+};
+bool operator < (const MyFieldInfo &lhs, const MyFieldInfo &rhs)
+{
+    return std::tie(lhs.parentClass, lhs.fieldName)
+         < std::tie(rhs.parentClass, rhs.fieldName);
+}
+
+struct MyFieldAssignmentInfo : public MyFieldInfo
+{
+    std::string value;
+};
+
+bool operator < (const MyFieldAssignmentInfo &lhs, const MyFieldAssignmentInfo &rhs)
+{
+    return std::tie(lhs.parentClass, lhs.fieldName, lhs.value)
+         < std::tie(rhs.parentClass, rhs.fieldName, rhs.value);
+}
+
+
+// try to limit the voluminous output a little
+static std::set<MyFieldAssignmentInfo> assignedSet;
+static std::set<MyFieldInfo> definitionSet;
+
+/** escape the value string to make it easier to parse the output file in python */
+std::string escape(std::string s)
+{
+    std::string out;
+    for (size_t i=0; i<s.length(); ++i)
+        if (int(s[i]) >= 32)
+            out += s[i];
+        else
+            out += "\\" + std::to_string((int)s[i]);
+    return out;
+}
+
+class SingleValFields:
+    public RecursiveASTVisitor<SingleValFields>, public loplugin::Plugin
+{
+public:
+    explicit SingleValFields(loplugin::InstantiationData const & data):
+        Plugin(data) {}
+
+    virtual void run() override
+    {
+        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 MyFieldAssignmentInfo & s : assignedSet)
+                output += "asgn:\t" + s.parentClass + "\t" + s.fieldName + "\t" + escape(s.value) + "\n";
+            for (const MyFieldInfo & s : definitionSet)
+                output += "defn:\t" + s.parentClass + "\t" + s.fieldName + "\t" + s.fieldType + "\t" + s.sourceLocation + "\n";
+            std::ofstream myfile;
+            myfile.open( WORKDIR "/loplugin.singlevalfields.log", std::ios::app | std::ios::out);
+            myfile << output;
+            myfile.close();
+        }
+        else
+        {
+            for (const MyFieldAssignmentInfo & s : assignedSet)
+                if (s.fieldDecl && compiler.getSourceManager().isInMainFile(s.fieldDecl->getBeginLoc()))
+                    report(
+                        DiagnosticsEngine::Warning,
+                        "assign %0",
+                        s.fieldDecl->getBeginLoc())
+                        << s.value;
+        }
+    }
+
+    bool shouldVisitTemplateInstantiations () const { return true; }
+    // to catch compiler-generated constructors
+    bool shouldVisitImplicitCode() const { return true; }
+
+    bool VisitFieldDecl( const FieldDecl* );
+    bool VisitVarDecl( const VarDecl* );
+    bool VisitMemberExpr( const MemberExpr* );
+    bool VisitDeclRefExpr( const DeclRefExpr* );
+    bool VisitCXXConstructorDecl( const CXXConstructorDecl* );
+//    bool VisitUnaryExprOrTypeTraitExpr( const UnaryExprOrTypeTraitExpr* );
+private:
+    void niceName(const DeclaratorDecl*, MyFieldInfo&);
+    void walkPotentialAssign( const DeclaratorDecl* fieldOrVarDecl, const Stmt* stmt );
+    std::string getExprValue(const Expr*);
+    const FunctionDecl* get_top_FunctionDecl_from_Stmt(const Stmt&);
+    void checkCallExpr(const Stmt* child, const CallExpr* callExpr, std::string& assignValue, bool& bPotentiallyAssignedTo);
+};
+
+void SingleValFields::niceName(const DeclaratorDecl* fieldOrVarDecl, MyFieldInfo& aInfo)
+{
+    const VarDecl* varDecl = dyn_cast<VarDecl>(fieldOrVarDecl);
+    const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(fieldOrVarDecl);
+    aInfo.fieldDecl = fieldDecl;
+    if (fieldDecl)
+        aInfo.parentClass = fieldDecl->getParent()->getQualifiedNameAsString();
+    else
+    {
+        if (auto parentRecordDecl = dyn_cast<CXXRecordDecl>(varDecl->getDeclContext()))
+            aInfo.parentClass = parentRecordDecl->getQualifiedNameAsString();
+        else if (auto parentMethodDecl = dyn_cast<CXXMethodDecl>(varDecl->getDeclContext()))
+            aInfo.parentClass = parentMethodDecl->getQualifiedNameAsString();
+        else if (auto parentFunctionDecl = dyn_cast<FunctionDecl>(varDecl->getDeclContext()))
+            aInfo.parentClass = parentFunctionDecl->getQualifiedNameAsString();
+        else if (isa<TranslationUnitDecl>(varDecl->getDeclContext()))
+            aInfo.parentClass = handler.getMainFileName().str();
+        else if (auto parentNamespaceDecl = dyn_cast<NamespaceDecl>(varDecl->getDeclContext()))
+            aInfo.parentClass = parentNamespaceDecl->getQualifiedNameAsString();
+        else if (isa<LinkageSpecDecl>(varDecl->getDeclContext()))
+            aInfo.parentClass = "extern"; // what to do here?
+        else
+        {
+            std::cout << "what is this? " << varDecl->getDeclContext()->getDeclKindName() << std::endl;
+            exit(1);
+        }
+    }
+    aInfo.fieldName = fieldOrVarDecl->getNameAsString();
+    aInfo.fieldType = fieldOrVarDecl->getType().getAsString();
+
+    SourceLocation expansionLoc = compiler.getSourceManager().getExpansionLoc( fieldOrVarDecl->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);
+}
+
+bool SingleValFields::VisitFieldDecl( const FieldDecl* fieldDecl )
+{
+    auto canonicalDecl = fieldDecl->getCanonicalDecl();
+
+    if( isInUnoIncludeFile( compiler.getSourceManager().getSpellingLoc(canonicalDecl->getLocation())) )
+        return true;
+
+    MyFieldInfo aInfo;
+    niceName(canonicalDecl, aInfo);
+    definitionSet.insert(aInfo);
+
+    if (fieldDecl->getInClassInitializer())
+    {
+        MyFieldAssignmentInfo aInfo;
+        niceName(canonicalDecl, aInfo);
+        aInfo.value = getExprValue(fieldDecl->getInClassInitializer());
+        assignedSet.insert(aInfo);
+    }
+
+    return true;
+}
+
+bool SingleValFields::VisitVarDecl( const VarDecl* varDecl )
+{
+    if (isa<ParmVarDecl>(varDecl))
+        return true;
+    if (varDecl->getType().isConstQualified())
+        return true;
+    if (!(varDecl->isStaticLocal() || varDecl->isStaticDataMember() || varDecl->hasGlobalStorage()))
+        return true;
+
+    auto canonicalDecl = varDecl->getCanonicalDecl();
+    if (!canonicalDecl->getLocation().isValid())
+        return true;
+
+    if( isInUnoIncludeFile( compiler.getSourceManager().getSpellingLoc(canonicalDecl->getLocation())) )
+        return true;
+
+    MyFieldInfo aInfo;
+    niceName(canonicalDecl, aInfo);
+    definitionSet.insert(aInfo);
+
+    if (varDecl->getInit())
+    {
+        MyFieldAssignmentInfo aInfo;
+        niceName(canonicalDecl, aInfo);
+        aInfo.value = getExprValue(varDecl->getInit());
+        assignedSet.insert(aInfo);
+    }
+
+    return true;
+}
+
+bool SingleValFields::VisitCXXConstructorDecl( const CXXConstructorDecl* decl )
+{
+    // doesn't count as a write to fields because it's self->self
+    if (decl->isCopyOrMoveConstructor())
+        return true;
+
+    for(auto it = decl->init_begin(); it != decl->init_end(); ++it)
+    {
+        const CXXCtorInitializer* init = *it;
+        const FieldDecl* fieldDecl = init->getMember();
+        if( !fieldDecl )
+            continue;
+        MyFieldAssignmentInfo aInfo;
+        niceName(fieldDecl, aInfo);
+        const Expr * expr = init->getInit();
+        // unwrap any single-arg constructors, this helps to find smart pointers
+        // that are only assigned nullptr
+        if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(expr))
+            if (cxxConstructExpr->getNumArgs() == 1)
+                expr = cxxConstructExpr->getArg(0);
+        aInfo.value = getExprValue(expr);
+        assignedSet.insert(aInfo);
+    }
+    return true;
+}
+
+bool SingleValFields::VisitMemberExpr( const MemberExpr* memberExpr )
+{
+    const ValueDecl* decl = memberExpr->getMemberDecl();
+    const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(decl);
+    if (!fieldDecl)
+        return true;
+    walkPotentialAssign(fieldDecl, memberExpr);
+    return true;
+}
+
+bool SingleValFields::VisitDeclRefExpr( const DeclRefExpr* declRefExpr )
+{
+    const VarDecl* varDecl = dyn_cast_or_null<VarDecl>(declRefExpr->getDecl());
+    if (!varDecl)
+        return true;
+    if (isa<ParmVarDecl>(varDecl))
+        return true;
+    if (varDecl->getType().isConstQualified())
+        return true;
+    if (!(varDecl->isStaticLocal() || varDecl->isStaticDataMember() || varDecl->hasGlobalStorage()))
+        return true;
+    walkPotentialAssign(varDecl, declRefExpr);
+    return true;
+}
+
+void SingleValFields::walkPotentialAssign( const DeclaratorDecl* fieldOrVarDecl, const Stmt* memberExpr )
+{
+    const FunctionDecl* parentFunction = getParentFunctionDecl(memberExpr);
+    if (parentFunction)
+    {
+        auto methodDecl = dyn_cast<CXXMethodDecl>(parentFunction);
+        if (methodDecl && (methodDecl->isCopyAssignmentOperator() || methodDecl->isMoveAssignmentOperator()))
+           return;
+        if (methodDecl && methodDecl->getIdentifier()
+            && (methodDecl->getName().startswith("Clone") || methodDecl->getName().startswith("clone")))
+           return;
+        auto cxxConstructorDecl = dyn_cast<CXXConstructorDecl>(parentFunction);
+        if (cxxConstructorDecl && cxxConstructorDecl->isCopyOrMoveConstructor())
+           return;
+    }
+
+    // walk up the tree until we find something interesting
+    const Stmt* child = memberExpr;
+    const Stmt* parent = getParentStmt(memberExpr);
+    bool bPotentiallyAssignedTo = false;
+    bool bDump = false;
+    std::string assignValue = "?";
+
+    // check for field being returned by non-const ref eg. Foo& getFoo() { return f; }
+    if (parentFunction && parent && isa<ReturnStmt>(parent)) {
+        const Stmt* parent2 = getParentStmt(parent);
+        if (parent2 && isa<CompoundStmt>(parent2)) {
+            QualType qt = parentFunction->getReturnType().getDesugaredType(compiler.getASTContext());
+            if (!qt.isConstQualified() && qt->isReferenceType()) {
+                bPotentiallyAssignedTo = true;
+            }
+        }
+    }
+
+    while (!bPotentiallyAssignedTo) {
+        // check for field being accessed by a reference variable e.g. Foo& f = m.foo;
+        auto parentsList = compiler.getASTContext().getParents(*child);
+        auto it = parentsList.begin();
+        if (it != parentsList.end()) {
+            const VarDecl *varDecl = it->get<VarDecl>();
+            if (varDecl) {
+                QualType qt = varDecl->getType().getDesugaredType(compiler.getASTContext());
+                if (!qt.isConstQualified() && qt->isReferenceType()) {
+                    bPotentiallyAssignedTo = true;
+                    break;
+                }
+            }
+        }
+
+        if (!parent) {
+            return;
+        }
+        if (isa<CastExpr>(parent) || isa<MemberExpr>(parent) || isa<ParenExpr>(parent) || isa<ParenListExpr>(parent)
+             || isa<ExprWithCleanups>(parent))
+        {
+            child = parent;
+            parent = getParentStmt(parent);
+        }
+        else if (isa<UnaryOperator>(parent))
+        {
+            const UnaryOperator* unaryOperator = dyn_cast<UnaryOperator>(parent);
+            int x = unaryOperator->getOpcode();
+            if (x == UO_AddrOf || x == UO_PostInc || x == UO_PostDec || x == UO_PreInc || x == UO_PreDec) {
+                assignValue = "?";
+                bPotentiallyAssignedTo = true;
+                break;
+            }
+            // cannot be assigned to anymore
+            break;
+        }
+        else if (auto callExpr = dyn_cast<CallExpr>(parent))
+        {
+            checkCallExpr(child, callExpr, assignValue, bPotentiallyAssignedTo);
+            break;
+        }
+        else if (isa<CXXConstructExpr>(parent))
+        {
+            const CXXConstructExpr* consExpr = dyn_cast<CXXConstructExpr>(parent);
+            const CXXConstructorDecl* consDecl = consExpr->getConstructor();
+            for (unsigned i = 0; i < consExpr->getNumArgs(); ++i) {
+                if (i >= consDecl->getNumParams()) // can happen in template code
+                    break;
+                if (consExpr->getArg(i) == child) {
+                    const ParmVarDecl* parmVarDecl = consDecl->getParamDecl(i);
+                    QualType qt = parmVarDecl->getType().getDesugaredType(compiler.getASTContext());
+                    if (!qt.isConstQualified() && qt->isReferenceType()) {
+                        bPotentiallyAssignedTo = true;
+                    }
+                    break;
+                }
+            }
+            break;
+        }
+        else if (isa<BinaryOperator>(parent))
+        {
+            const BinaryOperator* binaryOp = dyn_cast<BinaryOperator>(parent);
+            auto op = binaryOp->getOpcode();
+            if ( binaryOp->getLHS() != child ) {
+                // if the expr is on the RHS, do nothing
+            }
+            else if ( op == BO_Assign ) {
+                assignValue = getExprValue(binaryOp->getRHS());
+                bPotentiallyAssignedTo = true;
+            } else if ( 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 )
+            {
+                bPotentiallyAssignedTo = true;
+            }
+            break;
+        }
+        else if ( isa<CompoundStmt>(parent)
+                || isa<SwitchStmt>(parent) || isa<CaseStmt>(parent) || isa<DefaultStmt>(parent)
+                || isa<DoStmt>(parent) || isa<WhileStmt>(parent)
+                || isa<IfStmt>(parent)
+                || isa<ForStmt>(parent)
+                || isa<ReturnStmt>(parent)
+                || isa<CXXNewExpr>(parent)
+                || isa<CXXDeleteExpr>(parent)
+                || isa<ConditionalOperator>(parent)
+                || isa<CXXTypeidExpr>(parent)
+                || isa<ArraySubscriptExpr>(parent)
+                || isa<CXXDependentScopeMemberExpr>(parent)
+                || isa<DeclStmt>(parent)
+                || isa<UnaryExprOrTypeTraitExpr>(parent)
+                || isa<UnresolvedMemberExpr>(parent)
+                || isa<MaterializeTemporaryExpr>(parent)  //???
+                || isa<InitListExpr>(parent)
+                || isa<CXXUnresolvedConstructExpr>(parent)
+                || isa<LambdaExpr>(parent)
+                || isa<PackExpansionExpr>(parent)
+                || isa<CXXPseudoDestructorExpr>(parent)
+                )
+        {
+            break;
+        }
+        else if ( isa<ArrayInitLoopExpr>(parent) || isa<AtomicExpr>(parent) || isa<GCCAsmStmt>(parent) || isa<VAArgExpr>(parent))
+        {
+            bPotentiallyAssignedTo = true;
+            break;
+        }
+        else {
+            bPotentiallyAssignedTo = true;
+            bDump = true;
+            break;
+        }
+    }
+    if (bDump)
+    {
+        report(
+             DiagnosticsEngine::Warning,
+             "oh dear, what can the matter be?",
+              memberExpr->getBeginLoc())
+              << memberExpr->getSourceRange();
+        parent->dump();
+    }
+    if (bPotentiallyAssignedTo)
+    {
+        MyFieldAssignmentInfo aInfo;
+        niceName(fieldOrVarDecl, aInfo);
+        aInfo.value = assignValue;
+        assignedSet.insert(aInfo);
+    }
+}
+
+void SingleValFields::checkCallExpr(const Stmt* child, const CallExpr* callExpr, std::string& assignValue, bool& bPotentiallyAssignedTo)
+{
+    if (callExpr->getCallee() == child) {
+        return;
+    }
+    const FunctionDecl* functionDecl;
+    if (auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(callExpr)) {
+        functionDecl = memberCallExpr->getMethodDecl();
+    } else {
+        functionDecl = callExpr->getDirectCallee();
+    }
+    if (functionDecl) {
+        if (auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(callExpr)) {
+            if (operatorCallExpr->getArg(0) == child) {
+                const CXXMethodDecl* calleeMethodDecl = dyn_cast_or_null<CXXMethodDecl>(operatorCallExpr->getDirectCallee());
+                if (calleeMethodDecl) {
+                    if (operatorCallExpr->getOperator() == OO_Equal) {
+                        assignValue = getExprValue(operatorCallExpr->getArg(1));
+                        bPotentiallyAssignedTo = true;
+                        return;
+                    }
+                }
+            }
+        }
+        for (unsigned i = 0; i < callExpr->getNumArgs(); ++i) {
+            if (i >= functionDecl->getNumParams()) // can happen in template code
+                break;
+            if (callExpr->getArg(i) == child) {
+                const ParmVarDecl* parmVarDecl = functionDecl->getParamDecl(i);
+                QualType qt = parmVarDecl->getType().getDesugaredType(compiler.getASTContext());
+                if (!qt.isConstQualified() && qt->isReferenceType()) {
+                    assignValue = "?";
+                    bPotentiallyAssignedTo = true;
+                }
+                break;
+            }
+        }
+        return;
+    }
+    // check for function pointers
+    const FieldDecl* calleeFieldDecl = dyn_cast_or_null<FieldDecl>(callExpr->getCalleeDecl());
+    if (!calleeFieldDecl) {
+        return;
+    }
+    QualType qt = calleeFieldDecl->getType().getDesugaredType(compiler.getASTContext());
+    if (!qt->isPointerType()) {
+        return;
+    }
+    qt = qt->getPointeeType().getDesugaredType(compiler.getASTContext());
+    const FunctionProtoType* proto = qt->getAs<FunctionProtoType>();
+    if (!proto) {
+        return;
+    }
+    for (unsigned i = 0; i < callExpr->getNumArgs(); ++i) {
+        if (i >= proto->getNumParams()) // can happen in template code
+            break;
+        if (callExpr->getArg(i) == child) {
+            QualType qt = proto->getParamType(i).getDesugaredType(compiler.getASTContext());
+            if (!qt.isConstQualified() && qt->isReferenceType()) {
+                assignValue = "?";
+                bPotentiallyAssignedTo = true;
+            }
+            break;
+        }
+    }
+}
+
+
+std::string SingleValFields::getExprValue(const Expr* arg)
+{
+    if (!arg)
+        return "?";
+    arg = arg->IgnoreParenCasts();
+    arg = arg->IgnoreImplicit();
+    // ignore this, it seems to trigger an infinite recursion
+    if (isa<UnaryExprOrTypeTraitExpr>(arg))
+        return "?";
+    if (arg->isValueDependent())
+        return "?";
+    // for stuff like: OUString foo = "xxx";
+    if (auto stringLiteral = dyn_cast<clang::StringLiteral>(arg))
+    {
+        if (stringLiteral->getCharByteWidth() == 1)
+            return stringLiteral->getString().str();
+        return "?";
+    }
+    // ParenListExpr containing a CXXNullPtrLiteralExpr and has a NULL type pointer
+    if (auto parenListExpr = dyn_cast<ParenListExpr>(arg))
+    {
+        if (parenListExpr->getNumExprs() == 1)
+            return getExprValue(parenListExpr->getExpr(0));
+        return "?";
+    }
+    if (auto constructExpr = dyn_cast<CXXConstructExpr>(arg))
+    {
+        if (constructExpr->getNumArgs() >= 1
+            && isa<clang::StringLiteral>(constructExpr->getArg(0)))
+        {
+            auto stringLiteral = dyn_cast<clang::StringLiteral>(constructExpr->getArg(0));
+            if (stringLiteral->getCharByteWidth() == 1)
+                return stringLiteral->getString().str();
+            return "?";
+        }
+    }
+    if (arg->getType()->isFloatingType())
+    {
+        APFloat x1(0.0f);
+        if (arg->EvaluateAsFloat(x1, compiler.getASTContext()))
+        {
+            std::string s;
+            llvm::raw_string_ostream os(s);
+            x1.print(os);
+            return os.str();
+        }
+    }
+    APSInt x1;
+    if (compat::EvaluateAsInt(arg, x1, compiler.getASTContext()))
+        return compat::toString(x1, 10);
+    if (isa<CXXNullPtrLiteralExpr>(arg))
+        return "0";
+    return "?";
+}
+
+loplugin::Plugin::Registration< SingleValFields > X("singlevalfields", false);
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */