diff options
Diffstat (limited to 'compilerplugins/clang/nullptr.cxx')
| -rw-r--r-- | compilerplugins/clang/nullptr.cxx | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/compilerplugins/clang/nullptr.cxx b/compilerplugins/clang/nullptr.cxx new file mode 100644 index 000000000..b4a40b408 --- /dev/null +++ b/compilerplugins/clang/nullptr.cxx @@ -0,0 +1,428 @@ +/* -*- 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 <cstdlib> +#include <limits> +#include <set> + +#include "check.hxx" +#include "compat.hxx" +#include "plugin.hxx" + +namespace { + +char const * kindName(Expr::NullPointerConstantKind kind) { + switch (kind) { + case Expr::NPCK_ZeroExpression: + return "ZeroExpression"; + case Expr::NPCK_ZeroLiteral: + return "ZeroLiteral"; + case Expr::NPCK_CXX11_nullptr: + return "CXX11_nullptr"; + case Expr::NPCK_GNUNull: + return "GNUNull"; + case Expr::NPCK_NotNull: + break; // cannot happen + } + llvm_unreachable("unknown null pointer kind"); +} + +bool isAnyKindOfPointerType(QualType type) { + return type->isAnyPointerType() || type->isFunctionPointerType() + || type->isMemberPointerType(); +} + +bool isNullPointerCast(CastExpr const * expr) { + switch (expr->getCastKind()) { + case CK_NullToPointer: + case CK_NullToMemberPointer: + return true; + default: + return false; + } +} + +class Nullptr: + public loplugin::FilteringRewritePlugin<Nullptr> +{ +public: + explicit Nullptr(loplugin::InstantiationData const & data): + FilteringRewritePlugin(data) {} + + void run() override + { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); } + + bool VisitImplicitCastExpr(CastExpr const * expr); + + bool VisitGNUNullExpr(GNUNullExpr const * expr); + + bool VisitBinaryOperator(BinaryOperator const * expr); + + bool VisitCXXOperatorCallExpr(CXXOperatorCallExpr const * expr); + + bool VisitParmVarDecl(ParmVarDecl const * decl); + + bool TraverseConstructorInitializer(CXXCtorInitializer * init); + + bool TraverseLinkageSpecDecl(LinkageSpecDecl * decl); + + bool TraverseInitListExpr(InitListExpr * expr, DataRecursionQueue * queue = nullptr); + + // bool shouldVisitTemplateInstantiations() const { return true; } + +private: + bool isInLokIncludeFile(SourceLocation spellingLocation) const; + + bool isFromCIncludeFile(SourceLocation spellingLocation) const; + + bool isSharedCAndCppCode(SourceLocation location) const; + + void visitCXXCtorInitializer(CXXCtorInitializer const * init); + + void handleZero(Expr const * expr); + + void handleNull( + Expr const * expr, char const * castKind, + Expr::NullPointerConstantKind nullPointerKind); + + void rewriteOrWarn( + Expr const * expr, char const * castKind, + Expr::NullPointerConstantKind nullPointerKind, + char const * replacement); + + std::set<Expr const *> gnuNulls_; + unsigned int externCContexts_ = 0; +}; + +bool Nullptr::VisitImplicitCastExpr(CastExpr const * expr) { + if (ignoreLocation(expr)) { + return true; + } + if (!isNullPointerCast(expr)) { + return true; + } + Expr::NullPointerConstantKind k = expr->isNullPointerConstant( + compiler.getASTContext(), Expr::NPC_ValueDependentIsNotNull); + switch (k) { + case Expr::NPCK_NotNull: + k = expr->isNullPointerConstant( + compiler.getASTContext(), Expr::NPC_ValueDependentIsNull); + switch (k) { + case Expr::NPCK_NotNull: + break; + case Expr::NPCK_ZeroExpression: + case Expr::NPCK_ZeroLiteral: + report( + DiagnosticsEngine::Warning, + "suspicious ValueDependentIsNull %0", compat::getBeginLoc(expr)) + << kindName(k) << expr->getSourceRange(); + break; + default: + assert(false); // cannot happen + } + break; + case Expr::NPCK_CXX11_nullptr: + break; + default: + if (loplugin::TypeCheck(expr->getType()).Typedef("locale_t") + .GlobalNamespace()) + { + break; // POSIX locale_t is left unspecified + } + handleNull(expr->getSubExpr(), expr->getCastKindName(), k); + break; + } + return true; +} + +bool Nullptr::VisitGNUNullExpr(GNUNullExpr const * expr) { + if (ignoreLocation(expr)) { + return true; + } + handleNull(expr, nullptr, Expr::NPCK_GNUNull); + return true; +} + +bool Nullptr::VisitBinaryOperator(BinaryOperator const * expr) { + if (ignoreLocation(expr)) { + return true; + } + Expr const * e; + switch (expr->getOpcode()) { + case BO_EQ: + case BO_NE: + if (isAnyKindOfPointerType(expr->getRHS()->getType())) { + e = expr->getLHS(); + break; + } + // fall through + case BO_Assign: + if (isAnyKindOfPointerType(expr->getLHS()->getType())) { + e = expr->getRHS(); + break; + } + // fall through + default: + return true; + } + handleZero(e); + return true; +} + +bool Nullptr::VisitCXXOperatorCallExpr(CXXOperatorCallExpr const * expr) { + if (ignoreLocation(expr)) { + return true; + } + Expr const * e; + switch (expr->getOperator()) { + case OO_EqualEqual: + case OO_ExclaimEqual: + if (isAnyKindOfPointerType(expr->getArg(1)->getType())) { + e = expr->getArg(0); + break; + } + // fall through + case OO_Equal: + if (isAnyKindOfPointerType(expr->getArg(0)->getType())) { + e = expr->getArg(1); + break; + } + // fall through + default: + return true; + } + handleZero(e); + return true; +} + +bool Nullptr::VisitParmVarDecl(ParmVarDecl const * decl) { + if (ignoreLocation(decl)) { + return true; + } + if (!isAnyKindOfPointerType(decl->getType())) { + return true; + } + auto e = decl->getDefaultArg(); + if (e == nullptr) { + return true; + } + handleZero(e); + return true; +} + +bool Nullptr::TraverseConstructorInitializer(CXXCtorInitializer * init) { + visitCXXCtorInitializer(init); + return RecursiveASTVisitor::TraverseConstructorInitializer(init); +} + +bool Nullptr::TraverseLinkageSpecDecl(LinkageSpecDecl * decl) { + assert(externCContexts_ != std::numeric_limits<unsigned int>::max()); //TODO + ++externCContexts_; + bool ret = RecursiveASTVisitor::TraverseLinkageSpecDecl(decl); + assert(externCContexts_ != 0); + --externCContexts_; + return ret; +} + +bool Nullptr::TraverseInitListExpr(InitListExpr * expr, DataRecursionQueue * queue) { + return WalkUpFromInitListExpr(expr) + && TraverseSynOrSemInitListExpr( + expr->isSemanticForm() ? expr : expr->getSemanticForm(), queue); +} + +bool Nullptr::isInLokIncludeFile(SourceLocation spellingLocation) const { + return loplugin::hasPathnamePrefix( + getFilenameOfLocation(spellingLocation), + SRCDIR "/include/LibreOfficeKit/"); +} + +bool Nullptr::isFromCIncludeFile(SourceLocation spellingLocation) const { + return !compiler.getSourceManager().isInMainFile(spellingLocation) + && (StringRef( + compiler.getSourceManager().getPresumedLoc(spellingLocation) + .getFilename()) + .endswith(".h")); +} + +bool Nullptr::isSharedCAndCppCode(SourceLocation location) const { + // Assume that code is intended to be shared between C and C++ if it comes + // from an include file ending in .h, and is either in an extern "C" context + // or the body of a macro definition: + return + isFromCIncludeFile(compiler.getSourceManager().getSpellingLoc(location)) + && (externCContexts_ != 0 + || compiler.getSourceManager().isMacroBodyExpansion(location)); +} + +void Nullptr::visitCXXCtorInitializer(CXXCtorInitializer const * init) { + if (!init->isWritten()) { + return; + } + auto e = init->getInit(); + if (ignoreLocation(e)) { + return; + } + auto d = init->getAnyMember(); + if (d == nullptr || !isAnyKindOfPointerType(d->getType())) { + return; + } + if (auto e2 = dyn_cast<ParenListExpr>(e)) { + if (e2->getNumExprs() != 1) { + return; + } + e = e2->getExpr(0); + } else if (auto e2 = dyn_cast<InitListExpr>(e)) { + if (e2->getNumInits() != 1) { + return; + } + e = e2->getInit(0); + } + handleZero(e); +} + +void Nullptr::handleZero(Expr const * expr) { + //TODO: detect NPCK_ZeroExpression where appropriate + // Filter out ImplicitCastExpr that will be handled by + // VisitImplicitCastExpr: + if (auto ice = dyn_cast<ImplicitCastExpr>(expr)) { + if (isNullPointerCast(ice)) { + return; + } + } + auto const lit = dyn_cast<IntegerLiteral>(expr->IgnoreParenImpCasts()); + if (lit != nullptr && !lit->getValue().getBoolValue()) { + handleNull(expr, nullptr, Expr::NPCK_ZeroLiteral); + } +} + +void Nullptr::handleNull( + Expr const * expr, char const * castKind, + Expr::NullPointerConstantKind nullPointerKind) +{ + auto e = expr; + SourceLocation loc; + for (;;) { + e = e->IgnoreImpCasts(); + loc = compat::getBeginLoc(e); + while (compiler.getSourceManager().isMacroArgExpansion(loc)) { + loc = compiler.getSourceManager().getImmediateMacroCallerLoc(loc); + } + if (compiler.getSourceManager().isMacroBodyExpansion(loc)) { + if (Lexer::getImmediateMacroName( + loc, compiler.getSourceManager(), compiler.getLangOpts()) + == "NULL") + { + if (!compiler.getLangOpts().CPlusPlus) { + //TODO: if !castKind, warn if NULL is passed into fn call + // ellipsis, cast to void* + return; + } + loc = compat::getImmediateExpansionRange(compiler.getSourceManager(), loc).first; + if (ignoreLocation( + compiler.getSourceManager().getSpellingLoc(loc))) + { + return; + } + if (isInUnoIncludeFile( + compiler.getSourceManager().getSpellingLoc(loc)) + || isInLokIncludeFile( + compiler.getSourceManager().getSpellingLoc(loc)) + || isSharedCAndCppCode(loc)) + { + //TODO: if !castKind, warn if NULL is passed into fn call + // ellipsis, cast to void* + return; + } + } else if (ignoreLocation( + compiler.getSourceManager().getSpellingLoc(loc))) + { + return; + } + } + ParenExpr const * pe = dyn_cast<ParenExpr>(e); + if (pe == nullptr) { + break; + } + e = pe->getSubExpr(); + } + if (nullPointerKind == Expr::NPCK_GNUNull) { + if (castKind == nullptr) { + if (gnuNulls_.erase(expr) == 1) { + return; + } + } else { + auto const ok = gnuNulls_.insert(expr).second; + assert(ok); (void) ok; + } + } + auto const asMacro = !compiler.getLangOpts().CPlusPlus + || isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(loc)) + || isInLokIncludeFile(compiler.getSourceManager().getSpellingLoc(loc)) + || isSharedCAndCppCode(loc); + assert(!asMacro || nullPointerKind != Expr::NPCK_GNUNull); + rewriteOrWarn(e, castKind, nullPointerKind, asMacro ? "NULL" : "nullptr"); +} + +void Nullptr::rewriteOrWarn( + Expr const * expr, char const * castKind, + Expr::NullPointerConstantKind nullPointerKind, char const * replacement) +{ + if (rewriter != nullptr) { + SourceLocation locStart(compat::getBeginLoc(expr)); + while (compiler.getSourceManager().isMacroArgExpansion(locStart)) { + locStart = compiler.getSourceManager() + .getImmediateMacroCallerLoc(locStart); + } + if (compiler.getLangOpts().CPlusPlus + && compiler.getSourceManager().isMacroBodyExpansion(locStart) + && (Lexer::getImmediateMacroName( + locStart, compiler.getSourceManager(), + compiler.getLangOpts()) + == "NULL")) + { + locStart = compat::getImmediateExpansionRange(compiler.getSourceManager(), locStart) + .first; + } + SourceLocation locEnd(compat::getEndLoc(expr)); + while (compiler.getSourceManager().isMacroArgExpansion(locEnd)) { + locEnd = compiler.getSourceManager() + .getImmediateMacroCallerLoc(locEnd); + } + if (compiler.getLangOpts().CPlusPlus + && compiler.getSourceManager().isMacroBodyExpansion(locEnd) + && (Lexer::getImmediateMacroName( + locEnd, compiler.getSourceManager(), + compiler.getLangOpts()) + == "NULL")) + { + locEnd = compat::getImmediateExpansionRange(compiler.getSourceManager(), locEnd).first; + } + if (replaceText(SourceRange(compiler.getSourceManager().getSpellingLoc(locStart), compiler.getSourceManager().getSpellingLoc(locEnd)), replacement)) { + return; + } + } + if (castKind == nullptr) { + report(DiagnosticsEngine::Warning, "%0 -> %1", compat::getBeginLoc(expr)) + << kindName(nullPointerKind) << replacement + << expr->getSourceRange(); + } else { + report( + DiagnosticsEngine::Warning, "%0 ValueDependentIsNotNull %1 -> %2", + compat::getBeginLoc(expr)) + << castKind << kindName(nullPointerKind) << replacement + << expr->getSourceRange(); + } +} + +loplugin::Plugin::Registration<Nullptr> X("nullptr", true); + +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |