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Diffstat (limited to 'compilerplugins/clang/stringview.cxx')
| -rw-r--r-- | compilerplugins/clang/stringview.cxx | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/compilerplugins/clang/stringview.cxx b/compilerplugins/clang/stringview.cxx new file mode 100644 index 000000000000..530cf43d95a0 --- /dev/null +++ b/compilerplugins/clang/stringview.cxx @@ -0,0 +1,188 @@ +/* -*- 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_map> +#include <unordered_set> + +#include "plugin.hxx" +#include "check.hxx" +#include "clang/AST/CXXInheritance.h" +#include "clang/AST/StmtVisitor.h" + +/** + Look for places where we are making a substring copy of an OUString, and then passing it to a + function that takes a u16string_view, in which case it is more efficient to pass a view + of the OUString, rather than making a copy. + + TODO currently does not check if there is some other visible overload of the callee, that can take + a string_view. + TODO handle OUStringBuffer/OStringBuffer similarly +*/ + +namespace +{ +class StringView : public loplugin::FilteringPlugin<StringView> +{ +public: + explicit StringView(loplugin::InstantiationData const& data) + : FilteringPlugin(data) + { + } + + bool preRun() override { return true; } + + virtual void run() override + { + if (!preRun()) + return; + TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); + } + + bool VisitCallExpr(CallExpr const*); + bool VisitCXXConstructExpr(CXXConstructExpr const*); + bool VisitFunctionDecl(FunctionDecl const*); + bool VisitCXXOperatorCallExpr(CXXOperatorCallExpr const*); +}; + +bool StringView::VisitCallExpr(CallExpr const* callExpr) +{ + if (ignoreLocation(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) + { + const Expr* argExpr = callExpr->getArg(i); + auto paramDecl = functionDecl->getParamDecl(i); + auto paramRecordDecl = dyn_cast_or_null<RecordDecl>( + paramDecl->getType()->getUnqualifiedDesugaredType()->getAsTagDecl()); + if (!paramRecordDecl || !paramRecordDecl->getIdentifier() + || paramRecordDecl->getName() != "basic_string_view") + continue; + // unwrap the operator that converts to std::u16string_view + auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(argExpr->IgnoreImpCasts()); + if (!memberCallExpr) + continue; + // unwrap the call to copy() + auto memberCallExpr2 = dyn_cast<CXXMemberCallExpr>( + compat::IgnoreImplicit(memberCallExpr->getImplicitObjectArgument())); + if (!memberCallExpr2) + continue; + auto methodDecl = memberCallExpr2->getMethodDecl(); + if (!methodDecl->getIdentifier() || methodDecl->getName() != "copy") + continue; + report(DiagnosticsEngine::Warning, "rather than copy, pass with a view using subView()", + compat::getBeginLoc(argExpr)) + << argExpr->getSourceRange(); + } + + return true; +} + +bool StringView::VisitCXXOperatorCallExpr(CXXOperatorCallExpr const* cxxOperatorCallExpr) +{ + if (ignoreLocation(cxxOperatorCallExpr)) + return true; + + auto check = [&](const Expr* expr) -> void { + auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(compat::IgnoreImplicit(expr)); + if (!memberCallExpr) + return; + auto methodDecl = memberCallExpr->getMethodDecl(); + if (!methodDecl->getIdentifier() || methodDecl->getName() != "copy") + return; + report(DiagnosticsEngine::Warning, "rather than copy, pass with a view using subView()", + compat::getBeginLoc(expr)) + << expr->getSourceRange(); + }; + auto op = cxxOperatorCallExpr->getOperator(); + if (op == OO_Plus && cxxOperatorCallExpr->getNumArgs() == 2) + { + check(cxxOperatorCallExpr->getArg(0)); + check(cxxOperatorCallExpr->getArg(1)); + } + if (compat::isComparisonOp(cxxOperatorCallExpr)) + { + check(cxxOperatorCallExpr->getArg(0)); + check(cxxOperatorCallExpr->getArg(1)); + } + else if (op == OO_PlusEqual) + check(cxxOperatorCallExpr->getArg(1)); + else if (op == OO_Subscript) + check(cxxOperatorCallExpr->getArg(0)); + return true; +} + +bool StringView::VisitFunctionDecl(FunctionDecl const* functionDecl) +{ + if (ignoreLocation(functionDecl)) + return true; + // debugging + // if (functionDecl->getIdentifier() && functionDecl->getName() == "f1") + // functionDecl->dump(); + return true; +} + +bool StringView::VisitCXXConstructExpr(CXXConstructExpr const* constructExpr) +{ + if (ignoreLocation(constructExpr)) + return true; + + const CXXConstructorDecl* constructorDecl = constructExpr->getConstructor(); + if (!constructorDecl) + return true; + + unsigned len = std::min(constructExpr->getNumArgs(), constructorDecl->getNumParams()); + for (unsigned i = 0; i < len; ++i) + { + const Expr* argExpr = constructExpr->getArg(i); + auto paramDecl = constructorDecl->getParamDecl(i); + auto paramRecordDecl = dyn_cast_or_null<RecordDecl>( + paramDecl->getType()->getUnqualifiedDesugaredType()->getAsTagDecl()); + if (!paramRecordDecl || !paramRecordDecl->getIdentifier() + || paramRecordDecl->getName() != "basic_string_view") + continue; + // unwrap the operator that converts to std::u16string_view + auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(argExpr->IgnoreImpCasts()); + if (!memberCallExpr) + continue; + // unwrap the call to copy() + auto memberCallExpr2 = dyn_cast<CXXMemberCallExpr>( + compat::IgnoreImplicit(memberCallExpr->getImplicitObjectArgument())); + if (!memberCallExpr2) + continue; + auto methodDecl = memberCallExpr2->getMethodDecl(); + if (!methodDecl->getIdentifier() || methodDecl->getName() != "copy") + continue; + report(DiagnosticsEngine::Warning, "rather than copy, pass with a view using subView()", + compat::getBeginLoc(argExpr)) + << argExpr->getSourceRange(); + } + + return true; +} + +loplugin::Plugin::Registration<StringView> stringview("stringview"); +} + +#endif // LO_CLANG_SHARED_PLUGINS + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |