compilerplugins/clang/sequentialassign.cxx | 331 ++++++++++++++++++++++++
compilerplugins/clang/test/sequentialassign.cxx | 95 ++++++
solenv/CompilerTest_compilerplugins_clang.mk | 1
3 files changed, 427 insertions(+)
New commits:
commit b65f3fbb2beea99273371179703fcbc1d0ff326e
Author: Noel Grandin <noel.gran...@collabora.co.uk>
AuthorDate: Wed Apr 10 18:38:10 2019 +0200
Commit: Noel Grandin <noel.gran...@collabora.co.uk>
CommitDate: Thu Apr 11 08:52:49 2019 +0200
new loplugin sequentialassign
Look for places we are assigning to the same variable twice
in succession, which means we can simplify that to a single assign
Change-Id: I499d20e28f5595e81e927bef8e1bf364eea8ba91
Reviewed-on: https://gerrit.libreoffice.org/70531
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.gran...@collabora.co.uk>
diff --git a/compilerplugins/clang/sequentialassign.cxx
b/compilerplugins/clang/sequentialassign.cxx
new file mode 100644
index 000000000000..bc674694f8f1
--- /dev/null
+++ b/compilerplugins/clang/sequentialassign.cxx
@@ -0,0 +1,331 @@
+/* -*- 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 <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"
+
+/**
+ This is a kind of simplified dead-store analysis.
+
+ We are looking for patterns like:
+ Foo x = a;
+ x = b;
+ which can be simplified to
+ x = b
+
+ or
+ Foo x = a;
+ x = f(x)
+ which can be simplified to
+ Foo x = f(a)
+
+ TODO Improve this plugin to make it safer. We should really be checking the
following
+ conditions inside the RHS of the second statement:
+ If the variable is having it's address taken, or a non-const method
called on it,
+ on passed by non-const-ref.
+*/
+
+namespace
+{
+//static bool startswith(const std::string& rStr, const char* pSubStr) {
+// return rStr.compare(0, strlen(pSubStr), pSubStr) == 0;
+//}
+class SequentialAssign : public loplugin::FilteringPlugin<SequentialAssign>
+{
+public:
+ explicit SequentialAssign(loplugin::InstantiationData const& data)
+ : FilteringPlugin(data)
+ {
+ }
+
+ virtual void run() override
+ {
+ std::string fn(handler.getMainFileName());
+ loplugin::normalizeDotDotInFilePath(fn);
+ // places where the existing code style just looks better
+ // TODO lots of these would be unnecessary if I taught the plugin
+ // to ignore vars which are assigned to repeatedly
+ if (fn == SRCDIR "/vcl/source/helper/commandinfoprovider.cxx"
+ || fn == SRCDIR "/basegfx/source/polygon/b2dpolygonclipper.cxx"
+ || fn == SRCDIR "/i18nlangtag/source/isolang/insys.cxx"
+ || fn == SRCDIR "/vcl/unx/generic/fontmanager/fontconfig.cxx"
+ || fn == SRCDIR "/svtools/source/filter/exportdialog.cxx"
+ || fn == SRCDIR "/svtools/source/control/ruler.cxx"
+ || fn == SRCDIR "/basic/qa/cppunit/test_scanner.cxx"
+ || fn == SRCDIR "/basic/source/uno/namecont.cxx"
+ || fn == SRCDIR "/test/source/sheet/xnamedrange.cxx"
+ || fn == SRCDIR "/i18npool/qa/cppunit/test_breakiterator.cxx"
+ || fn == SRCDIR "/i18npool/source/localedata/LocaleNode.cxx"
+ || fn == SRCDIR
"/i18npool/source/transliteration/transliteration_Ignore.cxx"
+ || fn == SRCDIR "/i18npool/qa/cppunit/test_textsearch.cxx"
+ || fn == SRCDIR "/framework/source/jobs/jobdata.cxx"
+ || fn == SRCDIR "/framework/source/services/pathsettings.cxx"
+ || fn == SRCDIR "/xmloff/source/chart/SchXMLTools.cxx"
+ || fn == SRCDIR "/svx/source/tbxctrls/Palette.cxx"
+ || fn == SRCDIR
"/svx/source/sdr/contact/objectcontactofpageview.cxx"
+ || fn == SRCDIR "/svx/source/form/fmservs.cxx"
+ || fn == SRCDIR "/svx/source/svdraw/svdograf.cxx"
+ || fn == SRCDIR "/svx/source/accessibility/AccessibleShape.cxx"
+ || fn == SRCDIR "/svx/source/fmcomp/fmgridcl.cxx"
+ || fn == SRCDIR "/chart2/source/tools/CharacterProperties.cxx"
+ || fn == SRCDIR "/svx/source/dialog/dialcontrol.cxx"
+ || fn == SRCDIR "/connectivity/source/commontools/TTableHelper.cxx"
+ || fn == SRCDIR "/svx/source/dialog/_bmpmask.cxx"
+ || fn == SRCDIR
"/media/noel/disk2/libo4/cui/source/dialogs/SignSignatureLineDialog.cxx"
+ || fn == SRCDIR "/filter/source/msfilter/msdffimp.cxx"
+ || fn == SRCDIR "/filter/source/flash/swffilter.cxx"
+ || fn == SRCDIR "/cui/source/dialogs/SignSignatureLineDialog.cxx"
+ || fn == SRCDIR "/cui/source/dialogs/screenshotannotationdlg.cxx"
+ || fn == SRCDIR "/cui/source/options/optupdt.cxx"
+ || fn == SRCDIR
"/dbaccess/source/ui/querydesign/querycontroller.cxx"
+ || fn == SRCDIR "/dbaccess/source/ui/dlg/DbAdminImpl.cxx"
+ || fn == SRCDIR
"/dbaccess/source/ui/querydesign/JoinController.cxx"
+ || fn == SRCDIR "/dbaccess/source/ui/misc/TokenWriter.cxx"
+ || fn == SRCDIR "/dbaccess/source/ui/misc/TokenWriter.cxx"
+ || fn == SRCDIR
"/dbaccess/source/ui/misc/dbsubcomponentcontroller.cxx"
+ || fn == SRCDIR "/dbaccess/source/core/api/querycomposer.cxx"
+ || fn == SRCDIR "/desktop/source/lib/init.cxx"
+ || fn == SRCDIR "/lotuswordpro/source/filter/lwpfribmark.cxx"
+ || fn == SRCDIR "/tools/qa/cppunit/test_color.cxx"
+ || fn == SRCDIR "/sc/qa/unit/ucalc.cxx"
+ || fn == SRCDIR "/sc/source/ui/view/printfun.cxx"
+ || fn == SRCDIR "/sc/source/ui/view/preview.cxx"
+ || fn == SRCDIR "/sw/source/core/doc/tblafmt.cxx"
+ || fn == SRCDIR "/sw/source/core/draw/dflyobj.cxx"
+ || fn == SRCDIR "/sw/source/core/doc/DocumentDrawModelManager.cxx"
+ || fn == SRCDIR "/sw/source/core/edit/edfcol.cxx"
+ || fn == SRCDIR "/sw/source/filter/ww8/ww8toolbar.cxx"
+ || fn == SRCDIR "/sw/source/ui/fldui/fldvar.cxx"
+ || fn == SRCDIR "/sw/source/filter/ww8/ww8atr.cxx"
+ || fn == SRCDIR
"/sd/source/ui/accessibility/AccessiblePageShape.cxx"
+ || fn == SRCDIR "/xmlsecurity/source/xmlsec/nss/nssinitializer.cxx"
+ || fn == SRCDIR
"/sd/source/ui/slidesorter/cache/SlsRequestFactory.cxx"
+ || fn == SRCDIR
"/sd/source/ui/framework/configuration/ResourceId.cxx"
+ || fn == SRCDIR "/sd/source/filter/html/htmlex.cxx"
+ || fn == SRCDIR "/starmath/source/cfgitem.cxx"
+ || fn == SRCDIR "/ucb/source/ucp/ftp/ftpurl.cxx"
+ || fn == SRCDIR "/starmath/source/node.cxx"
+ || fn == SRCDIR "/ucb/source/ucp/cmis/certvalidation_handler.cxx"
+ || fn == SRCDIR
"/reportdesign/source/ui/inspection/GeometryHandler.cxx"
+ || fn == SRCDIR
"/reportdesign/source/core/api/ReportDefinition.cxx"
+ || fn == SRCDIR "/test/source/table/tablerow.cxx"
+ || fn == SRCDIR "/basegfx/test/B2DHomMatrixTest.cxx"
+ || fn == SRCDIR "/comphelper/qa/unit/base64_test.cxx"
+ || fn == SRCDIR "/testtools/source/bridgetest/bridgetest.cxx"
+ || fn == SRCDIR "/comphelper/qa/string/test_string.cxx"
+ || fn == SRCDIR "/cppu/qa/test_unotype.cxx"
+ || fn == SRCDIR "/cppu/qa/cppumaker/test_cppumaker.cxx"
+ || fn == SRCDIR "/o3tl/qa/test-lru_map.cxx" || fn == SRCDIR
"/svl/qa/unit/svl.cxx"
+ || fn == SRCDIR "/chart2/qa/extras/PivotChartTest.cxx"
+ || fn == SRCDIR "/chart2/qa/extras/chart2export.cxx"
+ || fn == SRCDIR "/writerfilter/qa/cppunittests/misc/misc.cxx"
+ || fn == SRCDIR "/sw/qa/extras/ww8export/ww8export.cxx"
+ || fn == SRCDIR "/sw/qa/extras/uiwriter/uiwriter.cxx")
+ return;
+ // inside ifdef
+ if (fn == SRCDIR "/vcl/source/filter/png/pngread.cxx"
+ || fn == SRCDIR "/vcl/source/window/syschild.cxx"
+ || fn == SRCDIR "/sal/osl/unx/security.cxx"
+ || fn == SRCDIR "/vcl/source/filter/png/pngwrite.cxx"
+ || fn == SRCDIR "/svtools/source/control/inettbc.cxx"
+ || fn == SRCDIR "/canvas/source/cairo/cairo_textlayout.cxx"
+ || fn == SRCDIR "/sal/qa/osl/file/osl_File.cxx")
+ return;
+ // taking address of variable
+ if (fn == SRCDIR "/vcl/unx/generic/dtrans/X11_selection.cxx")
+ return;
+ // other
+ if (fn == SRCDIR "/sc/source/core/tool/scmatrix.cxx"
+ || fn == SRCDIR
"/sal/qa/rtl/oustringbuffer/test_oustringbuffer_assign.cxx")
+ return;
+
+ TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+ }
+
+ bool VisitCompoundStmt(CompoundStmt const*);
+
+private:
+ const VarDecl* findSimpleAssign(Stmt const*);
+ bool isSimpleRHS(Expr const*);
+ Expr const* ignore(Expr const*);
+ void checkForSecondAssign(Stmt const* firstStmt, Stmt const* stmt, VarDecl
const* varDecl);
+};
+
+bool SequentialAssign::VisitCompoundStmt(CompoundStmt const* compoundStmt)
+{
+ if (ignoreLocation(compoundStmt))
+ return true;
+
+ auto it = compoundStmt->body_begin();
+ while (true)
+ {
+ if (it == compoundStmt->body_end())
+ break;
+ auto firstStmt = *it;
+ const VarDecl* foundVars = findSimpleAssign(firstStmt);
+ // reference types have slightly weird behaviour
+ if (!foundVars || foundVars->getType()->isReferenceType())
+ {
+ ++it;
+ continue;
+ }
+ ++it;
+ if (it == compoundStmt->body_end())
+ break;
+ checkForSecondAssign(firstStmt, *it, foundVars);
+ }
+
+ return true;
+}
+
+void SequentialAssign::checkForSecondAssign(Stmt const* firstStmt, Stmt const*
stmt,
+ VarDecl const* varDecl)
+{
+ if (auto exprCleanup = dyn_cast<ExprWithCleanups>(stmt))
+ stmt = exprCleanup->getSubExpr();
+
+ if (auto operatorCall = dyn_cast<CXXOperatorCallExpr>(stmt))
+ {
+ if (operatorCall->getOperator() == OO_Equal)
+ {
+ if (auto declRefExprLHS =
dyn_cast<DeclRefExpr>(ignore(operatorCall->getArg(0))))
+ if (declRefExprLHS->getDecl() == varDecl)
+ {
+ firstStmt->dump();
+ report(DiagnosticsEngine::Warning,
+ "simplify by merging with the preceding assignment",
+ compat::getBeginLoc(stmt))
+ << stmt->getSourceRange();
+ }
+ }
+ return;
+ }
+
+ if (auto binaryOp = dyn_cast<BinaryOperator>(stmt))
+ {
+ if (binaryOp->getOpcode() == BO_Assign)
+ {
+ if (auto declRefExpr =
dyn_cast<DeclRefExpr>(ignore(binaryOp->getLHS())))
+ if (declRefExpr->getDecl() == varDecl)
+ {
+ firstStmt->dump();
+ report(DiagnosticsEngine::Warning,
+ "simplify by merging with the preceding assignment",
+ compat::getBeginLoc(stmt))
+ << stmt->getSourceRange();
+ }
+ }
+ }
+}
+
+const VarDecl* SequentialAssign::findSimpleAssign(Stmt const* stmt)
+{
+ if (auto declStmt = dyn_cast<DeclStmt>(stmt))
+ if (declStmt->isSingleDecl())
+ if (auto varDeclLHS =
dyn_cast_or_null<VarDecl>(declStmt->getSingleDecl()))
+ {
+ if (varDeclLHS->getStorageDuration() == SD_Static)
+ return nullptr;
+ // if it's call-style init (e.g. OUString s("xxx")), we only
treat
+ // it as simple if it only contains a variable in the call
+ // (e.g. OUString s(x))
+ if (varDeclLHS->getInitStyle() ==
VarDecl::InitializationStyle::CallInit)
+ {
+ auto cxxConstructExpr
+ =
dyn_cast<CXXConstructExpr>(ignore(varDeclLHS->getInit()));
+ if (cxxConstructExpr)
+ {
+ if (cxxConstructExpr->getNumArgs() == 0)
+ return varDeclLHS;
+ if (cxxConstructExpr->getNumArgs() > 1)
+ return nullptr;
+ if
(!isa<DeclRefExpr>(ignore(cxxConstructExpr->getArg(0))))
+ return nullptr;
+ }
+ }
+ if (auto init = varDeclLHS->getInit())
+ if (isSimpleRHS(init))
+ return varDeclLHS;
+ }
+ if (auto operatorCall = dyn_cast<CXXOperatorCallExpr>(stmt))
+ if (operatorCall->getOperator() == OO_Equal)
+ if (auto declRefExprLHS =
dyn_cast<DeclRefExpr>(ignore(operatorCall->getArg(0))))
+ if (auto varDeclLHS =
dyn_cast<VarDecl>(declRefExprLHS->getDecl()))
+ if (isSimpleRHS(operatorCall->getArg(1)))
+ return varDeclLHS;
+ if (auto binaryOp = dyn_cast<BinaryOperator>(stmt))
+ if (binaryOp->getOpcode() == BO_Assign)
+ if (auto declRefExprLHS =
dyn_cast<DeclRefExpr>(ignore(binaryOp->getLHS())))
+ if (auto varDeclLHS =
dyn_cast<VarDecl>(declRefExprLHS->getDecl()))
+ if (isSimpleRHS(binaryOp->getRHS()))
+ return varDeclLHS;
+ return nullptr;
+}
+
+/**
+ Does the first statement have a relatively simply RHS we can inline into the
second statement?
+*/
+bool SequentialAssign::isSimpleRHS(Expr const* expr)
+{
+ expr = ignore(expr);
+
+ // code like
+ // Point aCurPos = rGlyphs
+ // always has a CXXConstructExpr wrapping the RHS
+ if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(expr))
+ if (cxxConstructExpr->getNumArgs() == 1)
+ expr = ignore(cxxConstructExpr->getArg(0));
+
+ if (!expr->isValueDependent()
+ && expr->isConstantInitializer(compiler.getASTContext(), false
/*ForRef*/))
+ return true;
+ if (isa<CXXMemberCallExpr>(expr))
+ return false;
+ if (isa<CXXOperatorCallExpr>(expr))
+ return false;
+ if (isa<UserDefinedLiteral>(expr))
+ return true;
+ if (isa<CallExpr>(expr))
+ return false;
+ if (isa<CastExpr>(expr))
+ return false;
+ if (isa<ArraySubscriptExpr>(expr))
+ return false;
+ if (isa<BinaryOperator>(expr))
+ return false;
+ if (isa<ConditionalOperator>(expr))
+ return false;
+ if (isa<UnaryOperator>(expr))
+ return false;
+ if (isa<CXXNewExpr>(expr))
+ return false;
+ if (auto memberExpr = dyn_cast<MemberExpr>(expr))
+ return isSimpleRHS(memberExpr->getBase());
+
+ return true;
+}
+
+Expr const* SequentialAssign::ignore(Expr const* expr)
+{
+ return expr->IgnoreImplicit()->IgnoreParens()->IgnoreImplicit();
+}
+
+// Off by default because of safety concerns, see TODO at top
+loplugin::Plugin::Registration<SequentialAssign> X("sequentialassign", false);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/test/sequentialassign.cxx
b/compilerplugins/clang/test/sequentialassign.cxx
new file mode 100644
index 000000000000..e656e1a7a304
--- /dev/null
+++ b/compilerplugins/clang/test/sequentialassign.cxx
@@ -0,0 +1,95 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4;
fill-column: 100 -*- */
+/*
+ * 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 <rtl/ustring.hxx>
+
+namespace test1
+{
+void f(OUString s1)
+{
+ OUString s2 = s1;
+ // expected-error@+1 {{simplify by merging with the preceding assignment
[loplugin:sequentialassign]}}
+ s2 = s2.getToken(0, '(');
+}
+}
+
+namespace test2
+{
+OUString s2;
+void f(OUString s1)
+{
+ s2 = s1;
+ // expected-error@+1 {{simplify by merging with the preceding assignment
[loplugin:sequentialassign]}}
+ s2 = s2.getToken(0, '(');
+}
+}
+
+namespace test3
+{
+struct VolumeInfo
+{
+ OUString getFileSystemName();
+};
+OUString aNullURL("");
+void f(VolumeInfo _aVolumeInfo)
+{
+ OUString aFileSysName(aNullURL);
+ // expected-error@+1 {{simplify by merging with the preceding assignment
[loplugin:sequentialassign]}}
+ aFileSysName = _aVolumeInfo.getFileSystemName();
+}
+}
+
+namespace test4
+{
+struct B3DVector
+{
+ B3DVector getPerpendicular();
+};
+void f(B3DVector aNewVPN)
+{
+ B3DVector aNewToTheRight = aNewVPN;
+ // expected-error@+1 {{simplify by merging with the preceding assignment
[loplugin:sequentialassign]}}
+ aNewToTheRight = aNewToTheRight.getPerpendicular();
+}
+}
+
+namespace test5
+{
+void f(OUString s, int x)
+{
+ int nPos = x;
+ // expected-error@+1 {{simplify by merging with the preceding assignment
[loplugin:sequentialassign]}}
+ nPos = s.indexOf("x", nPos);
+}
+}
+
+namespace test6
+{
+void f()
+{
+ OUString s2("xxxx");
+ s2 = s2.getToken(0, '('); // no warning expected
+}
+}
+
+namespace test7
+{
+class Class1
+{
+ OUString m_field1;
+ void foo(Class1& rOther)
+ {
+ OUString s = rOther.m_field1;
+ // expected-error@+1 {{simplify by merging with the preceding
assignment [loplugin:sequentialassign]}}
+ s = s.copy(1, 2);
+ }
+};
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s
cinkeys+=0=break: */
diff --git a/solenv/CompilerTest_compilerplugins_clang.mk
b/solenv/CompilerTest_compilerplugins_clang.mk
index 02a6d299039a..6128f8a4ed47 100644
--- a/solenv/CompilerTest_compilerplugins_clang.mk
+++ b/solenv/CompilerTest_compilerplugins_clang.mk
@@ -51,6 +51,7 @@ $(eval $(call
gb_CompilerTest_add_exception_objects,compilerplugins_clang, \
compilerplugins/clang/test/salcall \
compilerplugins/clang/test/sallogareas \
compilerplugins/clang/test/salunicodeliteral \
+ compilerplugins/clang/test/sequentialassign \
compilerplugins/clang/test/shouldreturnbool \
compilerplugins/clang/test/simplifybool \
compilerplugins/clang/test/simplifyconstruct \
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