diff options
Diffstat (limited to 'compilerplugins/clang/simplifypointertobool.cxx')
| -rw-r--r-- | compilerplugins/clang/simplifypointertobool.cxx | 444 |
1 files changed, 444 insertions, 0 deletions
diff --git a/compilerplugins/clang/simplifypointertobool.cxx b/compilerplugins/clang/simplifypointertobool.cxx new file mode 100644 index 000000000..097a78e16 --- /dev/null +++ b/compilerplugins/clang/simplifypointertobool.cxx @@ -0,0 +1,444 @@ +/* -*- 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 <algorithm> +#include <cassert> +#include <deque> +#include <string> +#include <iostream> +#include <fstream> +#include <set> + +#include <clang/AST/CXXInheritance.h> + +#include "plugin.hxx" +#include "check.hxx" + +/** + Simplify boolean expressions involving smart pointers e.g. + if (x.get()) + can be + if (x) +*/ +//TODO: Make this a shared plugin for Clang 12 (and possibly even for older Clang) again. + +namespace +{ +class SimplifyPointerToBool : public loplugin::FilteringRewritePlugin<SimplifyPointerToBool> +{ +public: + explicit SimplifyPointerToBool(loplugin::InstantiationData const& data) + : FilteringRewritePlugin(data) + { + } + + virtual void run() override + { + if (preRun()) + TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); + } + + bool VisitImplicitCastExpr(ImplicitCastExpr const*); + bool VisitBinaryOperator(BinaryOperator const*); + + bool PreTraverseUnaryOperator(UnaryOperator* expr) + { + if (expr->getOpcode() == UO_LNot) + { + contextuallyConvertedExprs_.push_back(expr->getSubExpr()->IgnoreParenImpCasts()); + } + return true; + } + + bool PostTraverseUnaryOperator(UnaryOperator* expr, bool) + { + if (expr->getOpcode() == UO_LNot) + { + assert(!contextuallyConvertedExprs_.empty()); + contextuallyConvertedExprs_.pop_back(); + } + return true; + } + + bool TraverseUnaryOperator(UnaryOperator* expr) + { + auto res = PreTraverseUnaryOperator(expr); + assert(res); + res = FilteringRewritePlugin::TraverseUnaryOperator(expr); + PostTraverseUnaryOperator(expr, res); + return res; + } + + bool PreTraverseBinaryOperator(BinaryOperator* expr) + { + auto const op = expr->getOpcode(); + if (op == BO_LAnd || op == BO_LOr) + { + contextuallyConvertedExprs_.push_back(expr->getLHS()->IgnoreParenImpCasts()); + contextuallyConvertedExprs_.push_back(expr->getRHS()->IgnoreParenImpCasts()); + } + return true; + } + + bool PostTraverseBinaryOperator(BinaryOperator* expr, bool) + { + auto const op = expr->getOpcode(); + if (op == BO_LAnd || op == BO_LOr) + { + assert(contextuallyConvertedExprs_.size() >= 2); + contextuallyConvertedExprs_.pop_back(); + contextuallyConvertedExprs_.pop_back(); + } + return true; + } + + bool TraverseBinaryOperator(BinaryOperator* expr) + { + auto res = PreTraverseBinaryOperator(expr); + assert(res); + res = FilteringRewritePlugin::TraverseBinaryOperator(expr); + PostTraverseBinaryOperator(expr, res); + return res; + } + + bool PreTraverseConditionalOperator(ConditionalOperator* expr) + { + contextuallyConvertedExprs_.push_back(expr->getCond()->IgnoreParenImpCasts()); + return true; + } + + bool PostTraverseConditionalOperator(ConditionalOperator*, bool) + { + assert(!contextuallyConvertedExprs_.empty()); + contextuallyConvertedExprs_.pop_back(); + return true; + } + + bool TraverseConditionalOperator(ConditionalOperator* expr) + { + auto res = PreTraverseConditionalOperator(expr); + assert(res); + res = FilteringRewritePlugin::TraverseConditionalOperator(expr); + PostTraverseConditionalOperator(expr, res); + return res; + } + + bool PreTraverseIfStmt(IfStmt* stmt) + { + contextuallyConvertedExprs_.push_back(stmt->getCond()->IgnoreParenImpCasts()); + return true; + } + + bool PostTraverseIfStmt(IfStmt*, bool) + { + assert(!contextuallyConvertedExprs_.empty()); + contextuallyConvertedExprs_.pop_back(); + return true; + } + + bool TraverseIfStmt(IfStmt* stmt) + { + auto res = PreTraverseIfStmt(stmt); + assert(res); + res = FilteringRewritePlugin::TraverseIfStmt(stmt); + PostTraverseIfStmt(stmt, res); + return res; + } + + bool PreTraverseWhileStmt(WhileStmt* stmt) + { + contextuallyConvertedExprs_.push_back(stmt->getCond()->IgnoreParenImpCasts()); + return true; + } + + bool PostTraverseWhileStmt(WhileStmt*, bool) + { + assert(!contextuallyConvertedExprs_.empty()); + contextuallyConvertedExprs_.pop_back(); + return true; + } + + bool TraverseWhileStmt(WhileStmt* stmt) + { + auto res = PreTraverseWhileStmt(stmt); + assert(res); + res = FilteringRewritePlugin::TraverseWhileStmt(stmt); + PostTraverseWhileStmt(stmt, res); + return res; + } + + bool PreTraverseDoStmt(DoStmt* stmt) + { + contextuallyConvertedExprs_.push_back(stmt->getCond()->IgnoreParenImpCasts()); + return true; + } + + bool PostTraverseDoStmt(DoStmt*, bool) + { + assert(!contextuallyConvertedExprs_.empty()); + contextuallyConvertedExprs_.pop_back(); + return true; + } + + bool TraverseDoStmt(DoStmt* stmt) + { + auto res = PreTraverseDoStmt(stmt); + assert(res); + res = FilteringRewritePlugin::TraverseDoStmt(stmt); + PostTraverseDoStmt(stmt, res); + return res; + } + + bool PreTraverseForStmt(ForStmt* stmt) + { + auto const e = stmt->getCond(); + if (e != nullptr) + { + contextuallyConvertedExprs_.push_back(e->IgnoreParenImpCasts()); + } + return true; + } + + bool PostTraverseForStmt(ForStmt* stmt, bool) + { + if (stmt->getCond() != nullptr) + { + assert(!contextuallyConvertedExprs_.empty()); + contextuallyConvertedExprs_.pop_back(); + } + return true; + } + + bool TraverseForStmt(ForStmt* stmt) + { + auto res = PreTraverseForStmt(stmt); + assert(res); + res = FilteringRewritePlugin::TraverseForStmt(stmt); + PostTraverseForStmt(stmt, res); + return res; + } + +private: + bool isContextuallyConverted(Expr const* expr) const + { + return std::find(contextuallyConvertedExprs_.begin(), contextuallyConvertedExprs_.end(), + expr) + != contextuallyConvertedExprs_.end(); + } + + // Get the source range starting at the "."or "->" (plus any preceding non-comment white space): + SourceRange getCallSourceRange(CXXMemberCallExpr const* expr) const + { + if (expr->getImplicitObjectArgument() == nullptr) + { + //TODO: Arguably, such a call of a `get` member function from within some member + // function (so that syntactically no caller is mentioned) should already be handled + // differently when reporting it (just "drop the get()" does not make sense), instead of + // being filtered here: + return {}; + } + // CXXMemberCallExpr::getExprLoc happens to return the location following the "." or "->": + auto start = compiler.getSourceManager().getSpellingLoc(expr->getExprLoc()); + if (!start.isValid()) + { + return {}; + } + for (;;) + { + start = Lexer::GetBeginningOfToken(start.getLocWithOffset(-1), + compiler.getSourceManager(), compiler.getLangOpts()); + auto const s = StringRef(compiler.getSourceManager().getCharacterData(start), + Lexer::MeasureTokenLength(start, compiler.getSourceManager(), + compiler.getLangOpts())); + if (s.empty() || s.startswith("\\\n")) + { + continue; + } + if (s != "." && s != "->") + { + return {}; + } + break; + } + for (;;) + { + auto start1 = Lexer::GetBeginningOfToken( + start.getLocWithOffset(-1), compiler.getSourceManager(), compiler.getLangOpts()); + auto const s = StringRef(compiler.getSourceManager().getCharacterData(start1), + Lexer::MeasureTokenLength(start1, compiler.getSourceManager(), + compiler.getLangOpts())); + if (!(s.empty() || s.startswith("\\\n"))) + { + break; + } + start = start1; + } + return SourceRange(start, compiler.getSourceManager().getSpellingLoc(expr->getEndLoc())); + } + + //TODO: There are some more places where an expression is contextually converted to bool, but + // those are probably not relevant for our needs here. + std::deque<Expr const*> contextuallyConvertedExprs_; +}; + +bool SimplifyPointerToBool::VisitImplicitCastExpr(ImplicitCastExpr const* castExpr) +{ + if (ignoreLocation(castExpr)) + return true; + if (castExpr->getCastKind() != CK_PointerToBoolean) + return true; + auto memberCallExpr + = dyn_cast<CXXMemberCallExpr>(castExpr->getSubExpr()->IgnoreParenImpCasts()); + if (!memberCallExpr) + return true; + auto methodDecl = memberCallExpr->getMethodDecl(); + if (!methodDecl || !methodDecl->getIdentifier() || methodDecl->getName() != "get") + return true; + // castExpr->dump(); + // methodDecl->getParent()->getTypeForDecl()->dump(); + if (!loplugin::isSmartPointerType(memberCallExpr->getImplicitObjectArgument())) + return true; + // if (isa<CXXOperatorCallExpr>(callExpr)) + // return true; + // const FunctionDecl* functionDecl; + // if (isa<CXXMemberCallExpr>(callExpr)) + // { + // functionDecl = dyn_cast<CXXMemberCallExpr>(callExpr)->getMethodDecl(); + // } + // else + // { + // functionDecl = callExpr->getDirectCallee(); + // } + // if (!functionDecl) + // return true; + // + // unsigned len = std::min(callExpr->getNumArgs(), functionDecl->getNumParams()); + // for (unsigned i = 0; i < len; ++i) + // { + // auto param = functionDecl->getParamDecl(i); + // auto paramTC = loplugin::TypeCheck(param->getType()); + // if (!paramTC.AnyBoolean()) + // continue; + // auto arg = callExpr->getArg(i)->IgnoreImpCasts(); + // auto argTC = loplugin::TypeCheck(arg->getType()); + // if (argTC.AnyBoolean()) + // continue; + // // sal_Bool is sometimes disguised + // if (isa<SubstTemplateTypeParmType>(arg->getType())) + // if (arg->getType()->getUnqualifiedDesugaredType()->isSpecificBuiltinType( + // clang::BuiltinType::UChar)) + // continue; + // if (arg->getType()->isDependentType()) + // continue; + // if (arg->getType()->isIntegerType()) + // { + // auto ret = getCallValue(arg); + // if (ret.hasValue() && (ret.getValue() == 1 || ret.getValue() == 0)) + // continue; + // // something like: priv->m_nLOKFeatures & LOK_FEATURE_DOCUMENT_PASSWORD + // if (isa<BinaryOperator>(arg->IgnoreParenImpCasts())) + // continue; + // // something like: pbEmbolden ? FcTrue : FcFalse + // if (isa<ConditionalOperator>(arg->IgnoreParenImpCasts())) + // continue; + // } + if (isContextuallyConverted(memberCallExpr)) + { + if (rewriter) + { + auto const range = getCallSourceRange(memberCallExpr); + if (range.isValid() && removeText(range)) + { + return true; + } + } + report(DiagnosticsEngine::Warning, "simplify, drop the get()", memberCallExpr->getExprLoc()) + << memberCallExpr->getSourceRange(); + } + else if (isa<ParenExpr>(castExpr->getSubExpr())) + { + if (rewriter) + { + auto const loc + = compiler.getSourceManager().getSpellingLoc(memberCallExpr->getBeginLoc()); + auto const range = getCallSourceRange(memberCallExpr); + if (loc.isValid() && range.isValid() && insertText(loc, "bool") && removeText(range)) + { + //TODO: atomically only change both or neither + return true; + } + } + report(DiagnosticsEngine::Warning, + "simplify, drop the get() and turn the surrounding parentheses into a functional " + "cast to bool", + memberCallExpr->getExprLoc()) + << memberCallExpr->getSourceRange(); + report(DiagnosticsEngine::Note, "surrounding parentheses here", + castExpr->getSubExpr()->getExprLoc()) + << castExpr->getSubExpr()->getSourceRange(); + } + else + { + if (rewriter) + { + auto const loc + = compiler.getSourceManager().getSpellingLoc(memberCallExpr->getBeginLoc()); + auto const range = getCallSourceRange(memberCallExpr); + if (loc.isValid() && range.isValid() && insertText(loc, "bool(") + && replaceText(range, ")")) + { + //TODO: atomically only change both or neither + return true; + } + } + report(DiagnosticsEngine::Warning, + "simplify, drop the get() and wrap the expression in a functional cast to bool", + memberCallExpr->getExprLoc()) + << memberCallExpr->getSourceRange(); + } + // report(DiagnosticsEngine::Note, "method here", param->getLocation()) + // << param->getSourceRange(); + return true; +} + +bool SimplifyPointerToBool::VisitBinaryOperator(BinaryOperator const* binOp) +{ + if (ignoreLocation(binOp)) + return true; + auto opCode = binOp->getOpcode(); + if (opCode != BO_EQ && opCode != BO_NE) + return true; + const Expr* possibleMemberCall = nullptr; + if (isa<CXXNullPtrLiteralExpr>(binOp->getLHS()->IgnoreParenImpCasts())) + possibleMemberCall = binOp->getRHS(); + else if (isa<CXXNullPtrLiteralExpr>(binOp->getRHS()->IgnoreParenImpCasts())) + possibleMemberCall = binOp->getLHS(); + else + return true; + auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(possibleMemberCall); + if (!memberCallExpr) + return true; + auto methodDecl = memberCallExpr->getMethodDecl(); + if (!methodDecl || !methodDecl->getIdentifier() || methodDecl->getName() != "get") + return true; + if (!loplugin::isSmartPointerType(memberCallExpr->getImplicitObjectArgument())) + return true; + report(DiagnosticsEngine::Warning, + std::string("simplify, convert to ") + (opCode == BO_EQ ? "'!x'" : "'x'"), + binOp->getExprLoc()) + << binOp->getSourceRange(); + return true; +} + +loplugin::Plugin::Registration<SimplifyPointerToBool> simplifypointertobool("simplifypointertobool", + true); + +} // namespace + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |