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Diffstat (limited to 'compilerplugins/clang/bufferadd.cxx')
| -rw-r--r-- | compilerplugins/clang/bufferadd.cxx | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/compilerplugins/clang/bufferadd.cxx b/compilerplugins/clang/bufferadd.cxx new file mode 100644 index 000000000..7b3eaf7e4 --- /dev/null +++ b/compilerplugins/clang/bufferadd.cxx @@ -0,0 +1,393 @@ +/* -*- 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/. + */ +#ifndef LO_CLANG_SHARED_PLUGINS + +#include <cassert> +#include <string> +#include <iostream> +#include <unordered_set> + +#include "plugin.hxx" +#include "check.hxx" +#include "config_clang.h" +#include "clang/AST/CXXInheritance.h" +#include "clang/AST/StmtVisitor.h" + +/** + Look for *StringBuffer append sequences which can be converted to *String + sequences. +*/ + +namespace +{ +class BufferAdd : public loplugin::FilteringPlugin<BufferAdd> +{ +public: + explicit BufferAdd(loplugin::InstantiationData const& data) + : FilteringPlugin(data) + { + } + + bool preRun() override + { + std::string fn(handler.getMainFileName()); + loplugin::normalizeDotDotInFilePath(fn); + if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sal/qa/rtl/oustring/")) + return false; + if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sal/qa/rtl/oustringbuffer/")) + return false; + if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sal/qa/rtl/strings/")) + return false; + if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sal/qa/OStringBuffer/")) + return false; + // some false + + if (loplugin::isSamePathname(fn, SRCDIR "/unoidl/source/sourcetreeprovider.cxx")) + return false; + if (loplugin::isSamePathname(fn, SRCDIR "/writerfilter/source/dmapper/StyleSheetTable.cxx")) + return false; + if (loplugin::isSamePathname(fn, SRCDIR "/writerfilter/source/dmapper/GraphicImport.cxx")) + return false; + if (loplugin::isSamePathname(fn, SRCDIR "/sdext/source/pdfimport/pdfparse/pdfparse.cxx")) + return false; + return true; + } + + void postRun() override + { + for (auto const& pair : goodMap) + if (!isa<ParmVarDecl>(pair.first) && + // reference types have slightly weird behaviour + !pair.first->getType()->isReferenceType() + && badMap.find(pair.first) == badMap.end()) + report(DiagnosticsEngine::Warning, + "convert this append sequence into a *String + sequence", + pair.first->getBeginLoc()) + << pair.first->getSourceRange(); + } + + virtual void run() override + { + if (!preRun()) + return; + TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); + postRun(); + } + + bool VisitStmt(Stmt const*); + bool VisitCallExpr(CallExpr const*); + bool VisitCXXConstructExpr(CXXConstructExpr const*); + bool VisitUnaryOperator(UnaryOperator const*); + +private: + void findBufferAssignOrAdd(const Stmt* parentStmt, Stmt const*); + Expr const* ignore(Expr const*); + bool isSideEffectFree(Expr const*); + bool isMethodOkToMerge(CXXMemberCallExpr const*); + void addToGoodMap(const VarDecl* varDecl, const Stmt* parentStmt); + + std::unordered_map<const VarDecl*, const Stmt*> goodMap; + std::unordered_set<const VarDecl*> badMap; +}; + +bool BufferAdd::VisitStmt(Stmt const* stmt) +{ + if (ignoreLocation(stmt)) + return true; + + if (!isa<CompoundStmt>(stmt) && !isa<CXXCatchStmt>(stmt) && !isa<CXXForRangeStmt>(stmt) + && !isa<CXXTryStmt>(stmt) && !isa<DoStmt>(stmt) && !isa<ForStmt>(stmt) && !isa<IfStmt>(stmt) + && !isa<SwitchStmt>(stmt) && !isa<WhileStmt>(stmt)) + return true; + + for (auto it = stmt->child_begin(); it != stmt->child_end(); ++it) + if (*it) + findBufferAssignOrAdd(stmt, *it); + + return true; +} + +bool BufferAdd::VisitCallExpr(CallExpr const* callExpr) +{ + if (ignoreLocation(callExpr)) + return true; + + for (unsigned i = 0; i != callExpr->getNumArgs(); ++i) + { + auto a = ignore(callExpr->getArg(i)); + if (auto declRefExpr = dyn_cast<DeclRefExpr>(a)) + if (auto varDecl = dyn_cast<VarDecl>(declRefExpr->getDecl())) + badMap.insert(varDecl); + } + return true; +} + +bool BufferAdd::VisitCXXConstructExpr(CXXConstructExpr const* callExpr) +{ + if (ignoreLocation(callExpr)) + return true; + + for (unsigned i = 0; i != callExpr->getNumArgs(); ++i) + { + auto a = ignore(callExpr->getArg(i)); + if (auto declRefExpr = dyn_cast<DeclRefExpr>(a)) + if (auto varDecl = dyn_cast<VarDecl>(declRefExpr->getDecl())) + badMap.insert(varDecl); + } + return true; +} + +bool BufferAdd::VisitUnaryOperator(const UnaryOperator* unaryOp) +{ + if (ignoreLocation(unaryOp)) + return true; + if (unaryOp->getOpcode() != UO_AddrOf) + return true; + auto a = ignore(unaryOp->getSubExpr()); + if (auto declRefExpr = dyn_cast<DeclRefExpr>(a)) + if (auto varDecl = dyn_cast<VarDecl>(declRefExpr->getDecl())) + badMap.insert(varDecl); + return true; +} + +void BufferAdd::findBufferAssignOrAdd(const Stmt* parentStmt, Stmt const* stmt) +{ + if (auto exprCleanup = dyn_cast<ExprWithCleanups>(stmt)) + stmt = exprCleanup->getSubExpr(); + if (auto switchCase = dyn_cast<SwitchCase>(stmt)) + stmt = switchCase->getSubStmt(); + if (auto declStmt = dyn_cast<DeclStmt>(stmt)) + { + if (declStmt->isSingleDecl()) + if (auto varDeclLHS = dyn_cast_or_null<VarDecl>(declStmt->getSingleDecl())) + { + auto tc = loplugin::TypeCheck(varDeclLHS->getType()); + if (!tc.Class("OUStringBuffer").Namespace("rtl").GlobalNamespace() + && !tc.Class("OStringBuffer").Namespace("rtl").GlobalNamespace()) + return; + if (varDeclLHS->getStorageDuration() == SD_Static) + return; + if (!varDeclLHS->hasInit()) + return; + auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(ignore(varDeclLHS->getInit())); + if (cxxConstructExpr) + { + addToGoodMap(varDeclLHS, parentStmt); + return; + } + if (!isSideEffectFree(varDeclLHS->getInit())) + badMap.insert(varDeclLHS); + else + addToGoodMap(varDeclLHS, parentStmt); + } + return; + } + + // check for single calls to buffer method + + if (auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(stmt)) + { + if (auto declRefExprLHS + = dyn_cast<DeclRefExpr>(ignore(memberCallExpr->getImplicitObjectArgument()))) + { + auto methodDecl = memberCallExpr->getMethodDecl(); + if (methodDecl && methodDecl->getIdentifier()) + if (auto varDeclLHS = dyn_cast<VarDecl>(declRefExprLHS->getDecl())) + { + auto tc = loplugin::TypeCheck(varDeclLHS->getType()); + if (tc.Class("OUStringBuffer").Namespace("rtl").GlobalNamespace() + || tc.Class("OStringBuffer").Namespace("rtl").GlobalNamespace()) + { + if (isMethodOkToMerge(memberCallExpr)) + addToGoodMap(varDeclLHS, parentStmt); + else + badMap.insert(varDeclLHS); + } + } + return; + } + } + + // now check for chained append calls + + auto expr = dyn_cast<Expr>(stmt); + if (!expr) + return; + auto tc = loplugin::TypeCheck(expr->getType()); + if (!tc.Class("OUStringBuffer").Namespace("rtl").GlobalNamespace() + && !tc.Class("OStringBuffer").Namespace("rtl").GlobalNamespace()) + return; + + // unwrap the chain (which runs from right to left) + const VarDecl* varDeclLHS = nullptr; + bool good = true; + while (true) + { + auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(expr); + if (!memberCallExpr) + break; + good &= isMethodOkToMerge(memberCallExpr); + + if (auto declRefExprLHS + = dyn_cast<DeclRefExpr>(ignore(memberCallExpr->getImplicitObjectArgument()))) + { + varDeclLHS = dyn_cast<VarDecl>(declRefExprLHS->getDecl()); + break; + } + expr = memberCallExpr->getImplicitObjectArgument(); + } + + if (varDeclLHS) + { + if (good) + addToGoodMap(varDeclLHS, parentStmt); + else + badMap.insert(varDeclLHS); + } +} + +void BufferAdd::addToGoodMap(const VarDecl* varDecl, const Stmt* parentStmt) +{ + // check that vars are all inside the same compoundstmt, if they are not, we cannot combine them + auto it = goodMap.find(varDecl); + if (it != goodMap.end()) + { + if (it->second == parentStmt) + return; + // don't treat these as parents, otherwise we eliminate .append.append sequences + if (isa<MemberExpr>(parentStmt)) + return; + if (isa<CXXMemberCallExpr>(parentStmt)) + return; + badMap.insert(varDecl); + } + else + goodMap.emplace(varDecl, parentStmt); +} + +bool BufferAdd::isMethodOkToMerge(CXXMemberCallExpr const* memberCall) +{ + auto methodDecl = memberCall->getMethodDecl(); + if (methodDecl->getNumParams() == 0) + return true; + + if (auto const id = methodDecl->getIdentifier()) + { + auto name = id->getName(); + if (name == "appendUninitialized" || name == "setLength" || name == "remove" + || name == "insert" || name == "appendAscii" || name == "appendUtf32") + return false; + } + + auto rhs = memberCall->getArg(0); + if (!isSideEffectFree(rhs)) + return false; + return true; +} + +Expr const* BufferAdd::ignore(Expr const* expr) +{ + return expr->IgnoreImplicit()->IgnoreParens()->IgnoreImplicit(); +} + +bool BufferAdd::isSideEffectFree(Expr const* expr) +{ + expr = ignore(expr); + // I don't think the OUStringAppend functionality can handle this efficiently + if (isa<ConditionalOperator>(expr)) + return false; + // Multiple statements have a well defined evaluation order (sequence points between them) + // but a single expression may be evaluated in arbitrary order; + // if there are side effects in one of the sub-expressions that have an effect on another subexpression, + // the result may be incorrect, and you don't necessarily notice in tests because the order is compiler-dependent. + // for example see commit afd743141f7a7dd05914d0872c9afe079f16fe0c where such a refactoring introduced such a bug. + // So only consider simple RHS expressions. + if (!expr->HasSideEffects(compiler.getASTContext())) + return true; + + // check for chained adds which are side-effect free + if (auto operatorCall = dyn_cast<CXXOperatorCallExpr>(expr)) + { + auto op = operatorCall->getOperator(); + if (op == OO_PlusEqual || op == OO_Plus) + if (isSideEffectFree(operatorCall->getArg(0)) + && isSideEffectFree(operatorCall->getArg(1))) + return true; + } + + if (auto callExpr = dyn_cast<CallExpr>(expr)) + { + // check for calls through OUString::number/OUString::unacquired + if (auto calleeMethodDecl = dyn_cast_or_null<CXXMethodDecl>(callExpr->getCalleeDecl())) + if (calleeMethodDecl && calleeMethodDecl->getIdentifier()) + { + if (callExpr->getNumArgs() > 0) + { + auto tc = loplugin::TypeCheck(calleeMethodDecl->getParent()); + if (tc.Class("OUString") || tc.Class("OString")) + { + if (isSideEffectFree(callExpr->getArg(0))) + return true; + } + } + } + if (auto calleeFunctionDecl = dyn_cast_or_null<FunctionDecl>(callExpr->getCalleeDecl())) + if (calleeFunctionDecl && calleeFunctionDecl->getIdentifier()) + { + auto name = calleeFunctionDecl->getName(); + // check for calls through OUStringToOString + if (name == "OUStringToOString" || name == "OStringToOUString") + if (isSideEffectFree(callExpr->getArg(0))) + return true; + // allowlist some known-safe methods + if (name.endswith("ResId") || name == "GetXMLToken") + if (isSideEffectFree(callExpr->getArg(0))) + return true; + } + // O[U]String::operator std::[u16]string_view: + if (auto const d = dyn_cast_or_null<CXXConversionDecl>(callExpr->getCalleeDecl())) + { + auto tc = loplugin::TypeCheck(d->getParent()); + if (tc.Class("OString") || tc.Class("OUString")) + { + return true; + } + } + } + + // sometimes we have a constructor call on the RHS + if (auto constructExpr = dyn_cast<CXXConstructExpr>(expr)) + { + auto dc = loplugin::DeclCheck(constructExpr->getConstructor()); + if (dc.MemberFunction().Class("OUString") || dc.MemberFunction().Class("OString") + || dc.MemberFunction().Class("OUStringBuffer") + || dc.MemberFunction().Class("OStringBuffer")) + if (constructExpr->getNumArgs() == 0 || isSideEffectFree(constructExpr->getArg(0))) + return true; + // Expr::HasSideEffects does not like stuff that passes through OUStringLiteral + auto dc2 = loplugin::DeclCheck(constructExpr->getConstructor()->getParent()); + if (dc2.Class("OUStringLiteral").Namespace("rtl").GlobalNamespace()) + return true; + } + + // when adding literals, we sometimes get this + if (auto functionalCastExpr = dyn_cast<CXXFunctionalCastExpr>(expr)) + { + auto tc = loplugin::TypeCheck(functionalCastExpr->getType()); + if (tc.Class("OUStringLiteral").Namespace("rtl").GlobalNamespace()) + return isSideEffectFree(functionalCastExpr->getSubExpr()); + } + + return false; +} + +loplugin::Plugin::Registration<BufferAdd> bufferadd("bufferadd"); +} + +#endif // LO_CLANG_SHARED_PLUGINS + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |