================ @@ -0,0 +1,488 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "UseConstexprCheck.h" +#include "../utils/ASTUtils.h" +#include "../utils/LexerUtils.h" +#include "clang/AST/Decl.h" +#include "clang/AST/RecursiveASTVisitor.h" +#include "clang/ASTMatchers/ASTMatchers.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallPtrSet.h" + +using namespace clang::ast_matchers; + +namespace clang::tidy::modernize { + +namespace { +AST_MATCHER(FunctionDecl, locationPermitsConstexpr) { + const bool IsInMainFile = + Finder->getASTContext().getSourceManager().isInMainFile( + Node.getLocation()); + + if (IsInMainFile) + return !Node.hasExternalFormalLinkage(); + return Node.isInlined(); +} + +AST_MATCHER(Expr, isCXX11ConstantExpr) { + return !Node.isValueDependent() && + Node.isCXX11ConstantExpr(Finder->getASTContext()); +} + +AST_MATCHER(DeclaratorDecl, isInMacro) { + const SourceRange R = + SourceRange(Node.getTypeSpecStartLoc(), Node.getLocation()); + + return Node.getLocation().isMacroID() || Node.getEndLoc().isMacroID() || + utils::rangeContainsMacroExpansion( + R, &Finder->getASTContext().getSourceManager()) || + utils::rangeIsEntirelyWithinMacroArgument( + R, &Finder->getASTContext().getSourceManager()); +} + +AST_MATCHER(Decl, hasNoRedecl) { + // There is always the actual declaration + return !Node.redecls().empty() && + std::next(Node.redecls_begin()) == Node.redecls_end(); +} + +AST_MATCHER(Decl, allRedeclsInSameFile) { + const SourceManager &SM = Finder->getASTContext().getSourceManager(); + const SourceLocation L = Node.getLocation(); + return llvm::all_of(Node.redecls(), [&](const Decl *ReDecl) { + return SM.isWrittenInSameFile(L, ReDecl->getLocation()); + }); +} +} // namespace + +static bool +satisfiesConstructorPropertiesUntil20(const CXXConstructorDecl *Ctor, + ASTContext &Ctx) { + const CXXRecordDecl *Rec = Ctor->getParent(); + + llvm::SmallPtrSet<const FieldDecl *, 8> UninitializedFields{ + Rec->field_begin(), Rec->field_end()}; + llvm::SmallPtrSet<const FieldDecl *, 4> Indirects{}; + + for (const CXXCtorInitializer *const Init : Ctor->inits()) { + if (const Type *InitType = Init->getBaseClass(); + InitType && InitType->isRecordType()) { + const auto *ConstructingInit = + llvm::dyn_cast<CXXConstructExpr>(Init->getInit()); + if (ConstructingInit && + !ConstructingInit->getConstructor()->isConstexprSpecified()) + return false; + } + + if (Init->isBaseInitializer()) + continue; + + if (Init->isMemberInitializer()) { + const FieldDecl *Field = Init->getMember(); + + if (Field->isAnonymousStructOrUnion()) + Indirects.insert(Field); + + UninitializedFields.erase(Field); + } + } + + for (const auto &Match : + match(cxxRecordDecl(forEach(indirectFieldDecl().bind("indirect"))), *Rec, + Ctx)) { + const auto *IField = Match.getNodeAs<IndirectFieldDecl>("indirect"); + + size_t NumInitializations = false; + for (const NamedDecl *ND : IField->chain()) + NumInitializations += Indirects.erase(llvm::dyn_cast<FieldDecl>(ND)); + + if (NumInitializations != 1) + return false; + + for (const NamedDecl *ND : IField->chain()) + UninitializedFields.erase(llvm::dyn_cast<FieldDecl>(ND)); + } + + return UninitializedFields.empty(); +} + +static bool isLiteralType(QualType QT, const ASTContext &Ctx, + bool ConservativeLiteralType); + +static bool isLiteralType(const Type *T, const ASTContext &Ctx, + const bool ConservativeLiteralType) { + if (!T) + return false; + + if (!T->isLiteralType(Ctx)) + return false; + + if (!ConservativeLiteralType) + return T->isLiteralType(Ctx) && !T->isVoidType(); + + if (T->isIncompleteType() || T->isIncompleteArrayType()) + return false; + + T = utils::unwrapPointee(T); + if (!T) + return false; + + assert(!T->isPointerOrReferenceType()); + + if (T->isIncompleteType() || T->isIncompleteArrayType()) + return false; + + if (T->isLiteralType(Ctx)) + return true; + + if (const CXXRecordDecl *Rec = T->getAsCXXRecordDecl()) { + if (!Rec->hasDefinition()) + return false; + + if (!Rec->hasTrivialDestructor()) + return false; + + if (!llvm::all_of(Rec->fields(), [&](const FieldDecl *Field) { + return isLiteralType(Field->getType(), Ctx, ConservativeLiteralType); + })) + return false; + + if (llvm::any_of(Rec->ctors(), [](const CXXConstructorDecl *Ctor) { + return !Ctor->isCopyOrMoveConstructor() && + Ctor->isConstexprSpecified(); + })) + return false; + + const auto AllBaseClassesAreLiteralTypes = + llvm::all_of(Rec->bases(), [&](const CXXBaseSpecifier &Base) { + return isLiteralType(Base.getType(), Ctx, ConservativeLiteralType); + }); + if (!AllBaseClassesAreLiteralTypes) + return false; + } + + if (const Type *ArrayElementType = T->getArrayElementTypeNoTypeQual()) + return isLiteralType(ArrayElementType, Ctx, ConservativeLiteralType); + + return false; +} + +static bool isLiteralType(QualType QT, const ASTContext &Ctx, + const bool ConservativeLiteralType) { + return !QT.isVolatileQualified() && + isLiteralType(QT.getTypePtr(), Ctx, ConservativeLiteralType); +} + +static bool satisfiesProperties11( + const FunctionDecl *FDecl, ASTContext &Ctx, + const bool ConservativeLiteralType, + const bool AddConstexprToMethodOfClassWithoutConstexprConstructor) { + if (FDecl->isConstexprSpecified()) + return true; + + const LangOptions LO = Ctx.getLangOpts(); + const auto *Method = llvm::dyn_cast<CXXMethodDecl>(FDecl); + if (Method && !Method->isStatic() && + !Method->getParent()->hasConstexprNonCopyMoveConstructor() && + !AddConstexprToMethodOfClassWithoutConstexprConstructor) + return false; + + if (const auto *Ctor = llvm::dyn_cast<CXXConstructorDecl>(FDecl); + Ctor && (!satisfiesConstructorPropertiesUntil20(Ctor, Ctx) || + Ctor->getParent()->getNumVBases() > 0)) + return false; + + if (const auto *Dtor = llvm::dyn_cast<CXXDestructorDecl>(FDecl); + Dtor && !Dtor->isTrivial()) + return false; + + if (!isLiteralType(FDecl->getReturnType(), Ctx, ConservativeLiteralType)) + return false; + + const bool OnlyHasParametersOfLiteralType = + llvm::all_of(FDecl->parameters(), [&](const ParmVarDecl *Param) { + return isLiteralType(Param->getType(), Ctx, ConservativeLiteralType); + }); + if (!OnlyHasParametersOfLiteralType) + return false; + + class Visitor11 : public clang::RecursiveASTVisitor<Visitor11> { + public: + using Base = clang::RecursiveASTVisitor<Visitor11>; + bool shouldVisitImplicitCode() const { return true; } + + Visitor11(ASTContext &Ctx, bool ConservativeLiteralType) + : Ctx(Ctx), ConservativeLiteralType(ConservativeLiteralType) {} + + bool WalkUpFromNullStmt(NullStmt *) { return false; } + bool WalkUpFromDeclStmt(DeclStmt *DS) { + Possible &= llvm::all_of(DS->decls(), [](const Decl *D) { + return llvm::isa<StaticAssertDecl, TypedefNameDecl, UsingDecl, + UsingDirectiveDecl>(D); + }); + return Possible; + } + + bool WalkUpFromExpr(Expr *) { return true; } + bool WalkUpFromCompoundStmt(CompoundStmt *S) { + for (const DynTypedNode &Node : Ctx.getParents(*S)) + if (Node.get<FunctionDecl>() != nullptr) + return true; + + Possible = false; + return false; + } + bool WalkUpFromStmt(Stmt *) { + Possible = false; + return false; + } + + bool WalkUpFromReturnStmt(ReturnStmt *) { + ++NumReturns; + if (NumReturns != 1U) { + Possible = false; + return false; + } + return true; + } + + bool WalkUpFromCastExpr(CastExpr *CE) { + if (llvm::is_contained( + { + CK_LValueBitCast, + CK_IntegralToPointer, + CK_PointerToIntegral, + }, + CE->getCastKind())) { + Possible = false; + return false; + } + return true; + } + + bool TraverseCXXDynamicCastExpr(CXXDynamicCastExpr *) { + Possible = false; + return false; + } + + bool TraverseCXXReinterpretCastExpr(CXXReinterpretCastExpr *) { + Possible = false; + return false; + } + + bool TraverseType(QualType QT, const bool TraverseQualifier = true) { + if (QT.isNull()) + return true; + if (!isLiteralType(QT, Ctx, ConservativeLiteralType)) { + Possible = false; + return false; + } + return Base::TraverseType(QT, TraverseQualifier); + } + + bool WalkUpFromCXXConstructExpr(CXXConstructExpr *CE) { + if (const CXXConstructorDecl *Ctor = CE->getConstructor(); + Ctor && !Ctor->isConstexprSpecified()) { + Possible = false; + return false; + } + + return true; + } + bool WalkUpFromCallExpr(CallExpr *CE) { + if (const auto *FDecl = + llvm::dyn_cast_if_present<FunctionDecl>(CE->getCalleeDecl()); + FDecl && !FDecl->isConstexprSpecified()) { + Possible = false; + return false; + } + return true; + } + + bool TraverseCXXNewExpr(CXXNewExpr *) { + Possible = false; + return false; + } + + bool TraverseDeclRefExpr(DeclRefExpr *DRef) { + if (DRef->getType().isVolatileQualified()) { + Possible = false; + return false; + } + return Base::TraverseDeclRefExpr(DRef); + } + + ASTContext &Ctx; + const bool ConservativeLiteralType; + bool Possible = true; + size_t NumReturns = 0; + }; + + Visitor11 V{Ctx, ConservativeLiteralType}; + V.TraverseDecl(const_cast<FunctionDecl *>(FDecl)); + return V.Possible; +} + +namespace { +AST_MATCHER_P2(FunctionDecl, satisfiesProperties, bool, ConservativeLiteralType, + bool, AddConstexprToMethodOfClassWithoutConstexprConstructor) { + ASTContext &Ctx = Finder->getASTContext(); + const LangOptions LO = Ctx.getLangOpts(); + + if (LO.CPlusPlus11) + return satisfiesProperties11( + &Node, Ctx, ConservativeLiteralType, + AddConstexprToMethodOfClassWithoutConstexprConstructor); + + return false; +} + +AST_MATCHER_P(VarDecl, satisfiesVariableProperties, bool, + ConservativeLiteralType) { + const ASTContext &Ctx = Finder->getASTContext(); + + const QualType QT = Node.getType(); + const Type *T = QT.getTypePtr(); + if (!T) + return false; + + if (!isLiteralType(QT, Ctx, ConservativeLiteralType)) + return false; + + const bool IsDeclaredInsideConstexprFunction = [&Node]() { + const auto *Func = llvm::dyn_cast<FunctionDecl>(Node.getDeclContext()); + return Func && Func->isConstexpr(); + }(); + + return !(Node.isStaticLocal() && IsDeclaredInsideConstexprFunction); +} +} // namespace + +void UseConstexprCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher( + functionDecl( + isDefinition(), + unless(anyOf(isConstexpr(), isImplicit(), hasExternalFormalLinkage(), + isInMacro(), isMain(), isDeleted(), isInStdNamespace(), + isExpansionInSystemHeader(), isExternC(), + cxxMethodDecl(ofClass(cxxRecordDecl(isLambda()))))), + locationPermitsConstexpr(), allRedeclsInSameFile(), + satisfiesProperties( + ConservativeLiteralType, + AddConstexprToMethodOfClassWithoutConstexprConstructor)) + .bind("func"), + this); + + const auto CallToNonConstexprFunction = + callExpr(callee(functionDecl(unless(isConstexpr())))); + + const auto VarSupportingConstexpr = + varDecl( + unless(anyOf(parmVarDecl(), isImplicit(), isInStdNamespace(), ---------------- localspook wrote:
Is there such a thing as an implicit variable declaration? :thinking: https://github.com/llvm/llvm-project/pull/162741 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
