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-rw-r--r--compilerplugins/clang/moveit.cxx271
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diff --git a/compilerplugins/clang/moveit.cxx b/compilerplugins/clang/moveit.cxx
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * Based on LLVM/Clang.
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ */
+
+#include <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include "config_clang.h"
+#include "plugin.hxx"
+#include "check.hxx"
+#include <unordered_set>
+#include <unordered_map>
+
+/*
+Look for local variables that can be std::move'd into parameters.
+
+TODO
+(*) Ideally we would use a proper data-flow analysis, to detect that the var is dead after this point,
+ like the one in clang at include/clang/Analysis/CFG.h
+(*) we could expand the set of approved/interesting types
+*/
+
+namespace
+{
+class MoveIt : public loplugin::FilteringPlugin<MoveIt>
+{
+public:
+ explicit MoveIt(loplugin::InstantiationData const& data)
+ : FilteringPlugin(data)
+ {
+ }
+
+ virtual bool preRun() override
+ {
+ std::string fn(handler.getMainFileName());
+ loplugin::normalizeDotDotInFilePath(fn);
+ // false +, needs to check if the moved-from var is outside a loop
+ if (loplugin::hasPathnamePrefix(
+ fn, SRCDIR "/drawinglayer/source/primitive3d/sdrdecompositiontools3d.cxx"))
+ return false;
+ if (loplugin::hasPathnamePrefix(
+ fn, SRCDIR "/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx"))
+ return false;
+ if (loplugin::hasPathnamePrefix(fn, SRCDIR "/drawinglayer/source/tools/emfphelperdata.cxx"))
+ return false;
+ if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sc/source/core/tool/reftokenhelper.cxx"))
+ return false;
+ if (loplugin::hasPathnamePrefix(fn,
+ SRCDIR "/svx/source/svdraw/svdotextpathdecomposition.cxx"))
+ return false;
+ if (loplugin::hasPathnamePrefix(fn, SRCDIR "/svx/source/svdraw/svdcrtv.cxx"))
+ return false;
+ if (loplugin::hasPathnamePrefix(fn, SRCDIR "/svx/source/table/tablehandles.cxx"))
+ return false;
+ if (loplugin::hasPathnamePrefix(fn, SRCDIR "/svx/source/xoutdev/xpool.cxx"))
+ return false;
+ return true;
+ }
+
+ virtual void run() override
+ {
+ if (preRun())
+ TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+ for (auto const& pair : m_possibles)
+ {
+ auto const& possible = pair.second;
+ report(DiagnosticsEngine::Warning, "can std::move this var into this param",
+ possible.argExpr->getBeginLoc());
+ report(DiagnosticsEngine::Note, "passing to this param",
+ possible.calleeParmVarDecl->getBeginLoc());
+ report(DiagnosticsEngine::Note, "local var declared here",
+ possible.localVarDecl->getBeginLoc());
+ report(DiagnosticsEngine::Note, "type declared here",
+ possible.recordDecl->getBeginLoc());
+ }
+ }
+
+ bool VisitCXXMemberCallExpr(const CXXMemberCallExpr*);
+ bool VisitCXXConstructExpr(const CXXConstructExpr*);
+ bool VisitDeclRefExpr(const DeclRefExpr*);
+
+private:
+ bool isInterestingType(QualType);
+ struct Possible
+ {
+ const Expr* argExpr;
+ const ParmVarDecl* calleeParmVarDecl;
+ const VarDecl* localVarDecl;
+ const CXXRecordDecl* recordDecl;
+ const DeclRefExpr* dre;
+ };
+ std::unordered_map<const VarDecl*, Possible> m_possibles;
+ std::unordered_set<const VarDecl*> m_rejected;
+};
+
+bool MoveIt::VisitCXXMemberCallExpr(const CXXMemberCallExpr* topExpr)
+{
+ if (ignoreLocation(topExpr))
+ return true;
+ const CXXMethodDecl* methodDecl = topExpr->getMethodDecl();
+ if (!methodDecl)
+ return true;
+
+ unsigned len = std::min(topExpr->getNumArgs(), methodDecl->getNumParams());
+ for (unsigned i = 0; i < len; ++i)
+ {
+ // check if the parameter is a moveable type
+ const ParmVarDecl* parmVarDecl = methodDecl->getParamDecl(i);
+ if (!parmVarDecl->getType()->isRecordType())
+ continue;
+ const CXXRecordDecl* recordDecl
+ = dyn_cast<CXXRecordDecl>(parmVarDecl->getType()->getAsRecordDecl());
+ if (!recordDecl || !recordDecl->hasMoveConstructor() || recordDecl->isTriviallyCopyable())
+ continue;
+ if (!isInterestingType(parmVarDecl->getType()))
+ continue;
+
+ // check if (a) we're making a copy to pass to the param and (b) we're making a copy of a local var
+ const Expr* argExpr = topExpr->getArg(i);
+ if (!argExpr)
+ continue;
+ const CXXConstructExpr* argSubExpr = dyn_cast<CXXConstructExpr>(argExpr->IgnoreImplicit());
+ if (!argSubExpr || argSubExpr->getNumArgs() == 0)
+ continue;
+ const DeclRefExpr* dre = dyn_cast<DeclRefExpr>(argSubExpr->getArg(0)->IgnoreImplicit());
+ if (!dre)
+ continue;
+ const VarDecl* localVarDecl = dyn_cast<VarDecl>(dre->getDecl());
+ if (!localVarDecl || localVarDecl->getType()->isReferenceType()
+ || localVarDecl->getType()->isPointerType() || !localVarDecl->hasLocalStorage())
+ continue;
+ // because sometimes the parameter type is some obscured STL thing
+ if (!isInterestingType(localVarDecl->getType()))
+ continue;
+
+ if (m_rejected.count(localVarDecl))
+ continue;
+
+ m_possibles[localVarDecl] = Possible{ argExpr, parmVarDecl, localVarDecl, recordDecl, dre };
+ }
+
+ return true;
+}
+
+bool MoveIt::VisitCXXConstructExpr(const CXXConstructExpr* topExpr)
+{
+ if (ignoreLocation(topExpr))
+ return true;
+ if (isa<CXXTemporaryObjectExpr>(topExpr))
+ return true;
+ const CXXConstructorDecl* methodDecl = topExpr->getConstructor();
+ if (!methodDecl)
+ return true;
+
+ unsigned len = std::min(topExpr->getNumArgs(), methodDecl->getNumParams());
+ for (unsigned i = 0; i < len; ++i)
+ {
+ // check if the parameter is a moveable type
+ const ParmVarDecl* parmVarDecl = methodDecl->getParamDecl(i);
+ if (!parmVarDecl->getType()->isRecordType())
+ continue;
+ const CXXRecordDecl* recordDecl
+ = dyn_cast<CXXRecordDecl>(parmVarDecl->getType()->getAsRecordDecl());
+ if (!recordDecl || !recordDecl->hasMoveConstructor() || recordDecl->isTriviallyCopyable())
+ continue;
+ if (!isInterestingType(parmVarDecl->getType()))
+ continue;
+
+ // check if (a) we're making a copy to pass to the param and (b) we're making a copy of a local var
+ const Expr* argExpr = topExpr->getArg(i);
+ if (!argExpr)
+ continue;
+ const CXXConstructExpr* argSubExpr = dyn_cast<CXXConstructExpr>(argExpr->IgnoreImplicit());
+ if (!argSubExpr || argSubExpr->getNumArgs() == 0)
+ continue;
+ const DeclRefExpr* dre = dyn_cast<DeclRefExpr>(argSubExpr->getArg(0)->IgnoreImplicit());
+ if (!dre)
+ continue;
+ const VarDecl* localVarDecl = dyn_cast<VarDecl>(dre->getDecl());
+ if (!localVarDecl || localVarDecl->getType()->isReferenceType()
+ || localVarDecl->getType()->isPointerType() || !localVarDecl->hasLocalStorage())
+ continue;
+ // because sometimes the parameter type is some obscured STL thing
+ if (!isInterestingType(localVarDecl->getType()))
+ continue;
+
+ if (m_rejected.count(localVarDecl))
+ continue;
+
+ m_possibles[localVarDecl] = Possible{ argExpr, parmVarDecl, localVarDecl, recordDecl, dre };
+ }
+
+ return true;
+}
+
+/// If we have pushed a possibility, and then we see that possibility again,
+/// then we cannot std::move it, because it is being referenced after being moved.
+///
+bool MoveIt::VisitDeclRefExpr(const DeclRefExpr* declRefExpr)
+{
+ if (ignoreLocation(declRefExpr))
+ return true;
+ const VarDecl* localVarDecl = dyn_cast<VarDecl>(declRefExpr->getDecl());
+ if (!localVarDecl)
+ return true;
+ auto it = m_possibles.find(localVarDecl);
+ if (it == m_possibles.end())
+ return true;
+ // ignoring the DeclRefExpr* for the expression where we found the Possible
+ if (it->second.dre == declRefExpr)
+ return true;
+ m_possibles.erase(it);
+ m_rejected.insert(localVarDecl);
+ return true;
+}
+
+/// Exclude boring types, so that we don't generate too many low-value conversions.
+/// e.g. for now I ignore ref-counted types like Sequence and OUString and css::uno::Reference,
+/// because that generates too many changes
+bool MoveIt::isInterestingType(QualType qt)
+{
+ if (qt->isEnumeralType())
+ return false;
+ if (!qt->isRecordType())
+ return false;
+
+ auto tc = loplugin::TypeCheck(qt);
+
+ // clang-format off
+ return !tc.ClassOrStruct("iterator")
+ && !tc.ClassOrStruct("const_iterator")
+ && !tc.Typedef("iterator")
+ && !tc.Typedef("const_iterator")
+ && !tc.Class("_Safe_iterator")
+ && !tc.Typedef("string")
+ && !tc.ClassOrStruct("shared_ptr").StdNamespace()
+ && !tc.ClassOrStruct("shared_ptr").Namespace("boost")
+ && !tc.Class("B2DHomMatrix").Namespace("basegfx").GlobalNamespace()
+ && !tc.Class("Pipe").Namespace("osl")
+ && !tc.Class("Any").Namespace("uno")
+ && !tc.Class("TypeDescription").Namespace("uno")
+ && !tc.Class("UnoInterfaceReference").Namespace("uno")
+ && !tc.Class("ByteSequence").Namespace("rtl").GlobalNamespace()
+ && !tc.Class("OUString").Namespace("rtl").GlobalNamespace()
+ && !tc.Class("OString").Namespace("rtl").GlobalNamespace()
+ && !tc.Class("BinaryAny")
+ && !tc.Class("Reference")
+ && !tc.Class("SvRef").Namespace("tools").GlobalNamespace()
+ && !tc.ClassOrStruct("sk_sp") // skia shared pointer
+ && !tc.ClassOrStruct("VclPtr")
+ && !tc.Typedef("IterString") // SalInstanceTreeView::IterString
+ && !tc.Typedef("svtree_render_args")
+ && !tc.Typedef("render_args") // weld::ComboBox::render_args
+ ;
+ // clang-format on
+}
+
+/// off by default because each warning needs to be hand checked to ensure it is not a false+
+loplugin::Plugin::Registration<MoveIt> moveit("moveit", false);
+
+} // namespace
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-10 11:24:26 +0000