office-gobmx/compilerplugins/clang/oncevar.cxx
Noel Grandin cc26cfd379 use more hasPathnamePrefix
Change-Id: I539e6aedad61d80b6ebe80104b77d720072395bd
2019-02-11 12:37:50 +02:00

413 lines
14 KiB
C++

/* -*- 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"
// Original idea from tml.
// Look for variables that are (a) initialised from zero or one constants. (b) only used in one spot.
// In which case, we might as well inline it.
namespace
{
Expr const * lookThroughInitListExpr(Expr const * expr) {
if (auto const ile = dyn_cast<InitListExpr>(expr->IgnoreParenImpCasts())) {
if (ile->getNumInits() == 1) {
return ile->getInit(0);
}
}
return expr;
}
class ConstantValueDependentExpressionVisitor:
public ConstStmtVisitor<ConstantValueDependentExpressionVisitor, bool>
{
ASTContext const & context_;
public:
ConstantValueDependentExpressionVisitor(ASTContext const & context):
context_(context) {}
bool Visit(Stmt const * stmt) {
assert(isa<Expr>(stmt));
auto const expr = cast<Expr>(stmt);
if (!expr->isValueDependent()) {
return expr->isEvaluatable(context_);
}
return ConstStmtVisitor::Visit(stmt);
}
bool VisitParenExpr(ParenExpr const * expr)
{ return Visit(expr->getSubExpr()); }
bool VisitCastExpr(CastExpr const * expr) {
return Visit(expr->getSubExpr());
}
bool VisitUnaryOperator(UnaryOperator const * expr)
{ return Visit(expr->getSubExpr()); }
bool VisitBinaryOperator(BinaryOperator const * expr) {
return Visit(expr->getLHS()) && Visit(expr->getRHS());
}
bool VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr const *) {
return true;
}
};
class OnceVar:
public loplugin::FilteringPlugin<OnceVar>
{
public:
explicit OnceVar(loplugin::InstantiationData const & data): FilteringPlugin(data) {}
virtual void run() override {
// ignore some files with problematic macros
std::string fn(handler.getMainFileName());
loplugin::normalizeDotDotInFilePath(fn);
// platform-specific stuff
if (fn == SRCDIR "/sal/osl/unx/thread.cxx"
|| fn == SRCDIR "/sot/source/base/formats.cxx"
|| fn == SRCDIR "/svl/source/config/languageoptions.cxx"
|| fn == SRCDIR "/sfx2/source/appl/appdde.cxx"
|| fn == SRCDIR "/configmgr/source/components.cxx"
|| fn == SRCDIR "/embeddedobj/source/msole/oleembed.cxx")
return;
// some of this is necessary
if (loplugin::hasPathnamePrefix( fn, SRCDIR "/sal/qa/"))
return;
if (loplugin::hasPathnamePrefix( fn, SRCDIR "/comphelper/qa/"))
return;
// TODO need to check calls via function pointer
if (fn == SRCDIR "/i18npool/source/textconversion/textconversion_zh.cxx"
|| fn == SRCDIR "/i18npool/source/localedata/localedata.cxx")
return;
// debugging stuff
if (fn == SRCDIR "/sc/source/core/data/dpcache.cxx"
|| fn == SRCDIR "/sw/source/core/layout/dbg_lay.cxx"
|| fn == SRCDIR "/sw/source/core/layout/ftnfrm.cxx")
return;
// TODO taking local reference to variable
if (fn == SRCDIR "/sc/source/filter/excel/xechart.cxx")
return;
// macros managing to generate to a valid warning
if (fn == SRCDIR "/solenv/bin/concat-deps.c")
return;
// TODO bug in the plugin
if (fn == SRCDIR "/vcl/unx/generic/app/saldisp.cxx")
return;
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
for (auto const & varDecl : maVarDeclSet)
{
if (maVarDeclToIgnoreSet.find(varDecl) != maVarDeclToIgnoreSet.end())
continue;
int noUses = 0;
auto it = maVarUsesMap.find(varDecl);
if (it != maVarUsesMap.end())
noUses = it->second;
if (noUses > 1)
continue;
report(DiagnosticsEngine::Warning,
"var used only once, should be inlined or declared const",
varDecl->getLocation())
<< varDecl->getSourceRange();
if (it != maVarUsesMap.end())
report(DiagnosticsEngine::Note,
"used here",
maVarUseSourceRangeMap[varDecl].getBegin())
<< maVarUseSourceRangeMap[varDecl];
}
}
bool VisitMemberExpr(MemberExpr const * expr) {
// ignore cases like:
// const OUString("xxx") xxx;
// rtl_something(xxx.pData);
// where we cannot inline the declaration.
if (isa<FieldDecl>(expr->getMemberDecl())) {
recordIgnore(expr);
}
return true;
}
bool VisitUnaryOperator(UnaryOperator const * expr) {
// if we take the address of it, or we modify it, ignore it
UnaryOperator::Opcode op = expr->getOpcode();
if (op == UO_AddrOf || op == UO_PreInc || op == UO_PostInc
|| op == UO_PreDec || op == UO_PostDec)
{
recordIgnore(expr->getSubExpr());
}
return true;
}
bool VisitBinaryOperator(BinaryOperator const * expr) {
// if we assign it another value, or modify it, ignore it
BinaryOperator::Opcode op = expr->getOpcode();
if (op == BO_Assign || op == BO_PtrMemD || op == BO_PtrMemI || op == BO_MulAssign
|| op == BO_DivAssign || op == BO_RemAssign || op == BO_AddAssign
|| op == BO_SubAssign || op == BO_ShlAssign || op == BO_ShrAssign
|| op == BO_AndAssign || op == BO_XorAssign || op == BO_OrAssign)
{
recordIgnore(expr->getLHS());
}
return true;
}
bool VisitCallExpr(CallExpr const * expr) {
unsigned firstArg = 0;
if (auto const cmce = dyn_cast<CXXMemberCallExpr>(expr)) {
if (auto const e1 = cmce->getMethodDecl()) {
if (!(e1->isConst() || e1->isStatic())) {
recordIgnore(cmce->getImplicitObjectArgument());
}
} else if (auto const e2 = dyn_cast<BinaryOperator>(
cmce->getCallee()->IgnoreParenImpCasts()))
{
switch (e2->getOpcode()) {
case BO_PtrMemD:
case BO_PtrMemI:
if (!e2->getRHS()->getType()->getAs<MemberPointerType>()
->getPointeeType()->getAs<FunctionProtoType>()
->isConst())
{
recordIgnore(e2->getLHS());
}
break;
default:
break;
}
}
} else if (auto const coce = dyn_cast<CXXOperatorCallExpr>(expr)) {
if (auto const cmd = dyn_cast_or_null<CXXMethodDecl>(
coce->getDirectCallee()))
{
if (!cmd->isStatic()) {
assert(coce->getNumArgs() != 0);
if (!cmd->isConst()) {
recordIgnore(coce->getArg(0));
}
firstArg = 1;
}
}
}
// ignore those ones we are passing by reference
const FunctionDecl* calleeFunctionDecl = expr->getDirectCallee();
if (calleeFunctionDecl) {
for (unsigned i = firstArg; i < expr->getNumArgs(); ++i) {
if (i < calleeFunctionDecl->getNumParams()) {
QualType qt { calleeFunctionDecl->getParamDecl(i)->getType() };
if (loplugin::TypeCheck(qt).LvalueReference().NonConst()) {
recordIgnore(expr->getArg(i));
}
if (loplugin::TypeCheck(qt).Pointer().NonConst()) {
recordIgnore(expr->getArg(i));
}
}
}
}
return true;
}
bool VisitCXXConstructExpr(CXXConstructExpr const * expr) {
// ignore those ones we are passing by reference
const CXXConstructorDecl* cxxConstructorDecl = expr->getConstructor();
for (unsigned i = 0; i < expr->getNumArgs(); ++i) {
if (i < cxxConstructorDecl->getNumParams()) {
QualType qt { cxxConstructorDecl->getParamDecl(i)->getType() };
if (loplugin::TypeCheck(qt).LvalueReference().NonConst()) {
recordIgnore(expr->getArg(i));
}
if (loplugin::TypeCheck(qt).Pointer().NonConst()) {
recordIgnore(expr->getArg(i));
}
}
}
return true;
}
bool VisitDeclRefExpr( const DeclRefExpr* );
bool VisitVarDecl( const VarDecl* );
bool TraverseFunctionDecl( FunctionDecl* functionDecl );
private:
std::unordered_set<VarDecl const *> maVarDeclSet;
std::unordered_set<VarDecl const *> maVarDeclToIgnoreSet;
std::unordered_map<VarDecl const *, int> maVarUsesMap;
std::unordered_map<VarDecl const *, SourceRange> maVarUseSourceRangeMap;
bool isConstantValueDependentExpression(Expr const * expr) {
return ConstantValueDependentExpressionVisitor(compiler.getASTContext())
.Visit(expr);
}
void recordIgnore(Expr const * expr) {
for (;;) {
expr = expr->IgnoreParenImpCasts();
if (auto const e = dyn_cast<MemberExpr>(expr)) {
if (isa<FieldDecl>(e->getMemberDecl())) {
expr = e->getBase();
continue;
}
}
if (auto const e = dyn_cast<ArraySubscriptExpr>(expr)) {
expr = e->getBase();
continue;
}
if (auto const e = dyn_cast<BinaryOperator>(expr)) {
if (e->getOpcode() == BO_PtrMemD) {
expr = e->getLHS();
continue;
}
}
break;
}
auto const dre = dyn_cast<DeclRefExpr>(expr);
if (dre == nullptr) {
return;
}
auto const var = dyn_cast<VarDecl>(dre->getDecl());
if (var == nullptr) {
return;
}
maVarDeclToIgnoreSet.insert(var);
}
};
bool OnceVar::TraverseFunctionDecl( FunctionDecl* functionDecl )
{
// Ignore functions that contains #ifdef-ery, can be quite tricky
// to make useful changes when this plugin fires in such functions
if (containsPreprocessingConditionalInclusion(
functionDecl->getSourceRange()))
return true;
return RecursiveASTVisitor::TraverseFunctionDecl(functionDecl);
}
bool OnceVar::VisitVarDecl( const VarDecl* varDecl )
{
if (ignoreLocation(varDecl)) {
return true;
}
if (auto const init = varDecl->getInit()) {
recordIgnore(lookThroughInitListExpr(init));
}
if (varDecl->isExceptionVariable() || isa<ParmVarDecl>(varDecl)) {
return true;
}
// ignore stuff in header files (which should really not be there, but anyhow)
if (!compiler.getSourceManager().isInMainFile(varDecl->getLocation())) {
return true;
}
// Ignore macros like FD_ZERO
if (compiler.getSourceManager().isMacroBodyExpansion(compat::getBeginLoc(varDecl))) {
return true;
}
if (varDecl->hasGlobalStorage()) {
return true;
}
auto const tc = loplugin::TypeCheck(varDecl->getType());
if (!varDecl->getType().isCXX11PODType(compiler.getASTContext())
&& !tc.Class("OString").Namespace("rtl").GlobalNamespace()
&& !tc.Class("OUString").Namespace("rtl").GlobalNamespace()
&& !tc.Class("OStringBuffer").Namespace("rtl").GlobalNamespace()
&& !tc.Class("OUStringBuffer").Namespace("rtl").GlobalNamespace()
&& !tc.Class("Color").GlobalNamespace()
&& !tc.Class("Pair").GlobalNamespace()
&& !tc.Class("Point").GlobalNamespace()
&& !tc.Class("Size").GlobalNamespace()
&& !tc.Class("Range").GlobalNamespace()
&& !tc.Class("Selection").GlobalNamespace()
&& !tc.Class("Rectangle").Namespace("tools").GlobalNamespace())
{
return true;
}
if (varDecl->getType()->isPointerType())
return true;
// if it's declared const, ignore it, it's there to make the code easier to read
if (tc.Const())
return true;
if (!varDecl->hasInit())
return true;
// check for string or scalar literals
bool foundStringLiteral = false;
const Expr * initExpr = varDecl->getInit();
if (auto e = dyn_cast<ExprWithCleanups>(initExpr)) {
initExpr = e->getSubExpr();
}
if (isa<clang::StringLiteral>(initExpr)) {
foundStringLiteral = true;
} else if (auto constructExpr = dyn_cast<CXXConstructExpr>(initExpr)) {
if (constructExpr->getNumArgs() == 0) {
foundStringLiteral = true; // i.e., empty string
} else {
auto stringLit2 = dyn_cast<clang::StringLiteral>(constructExpr->getArg(0));
foundStringLiteral = stringLit2 != nullptr;
}
}
if (!foundStringLiteral) {
auto const init = varDecl->getInit();
if (!(init->isValueDependent()
? isConstantValueDependentExpression(init)
: init->isConstantInitializer(
compiler.getASTContext(), false/*ForRef*/)))
{
return true;
}
}
maVarDeclSet.insert(varDecl);
return true;
}
bool OnceVar::VisitDeclRefExpr( const DeclRefExpr* declRefExpr )
{
if (ignoreLocation(declRefExpr)) {
return true;
}
const Decl* decl = declRefExpr->getDecl();
if (!isa<VarDecl>(decl) || isa<ParmVarDecl>(decl)) {
return true;
}
const VarDecl * varDecl = dyn_cast<VarDecl>(decl)->getCanonicalDecl();
// ignore stuff in header files (which should really not be there, but anyhow)
if (!compiler.getSourceManager().isInMainFile(varDecl->getLocation())) {
return true;
}
if (maVarUsesMap.find(varDecl) == maVarUsesMap.end()) {
maVarUsesMap[varDecl] = 1;
maVarUseSourceRangeMap[varDecl] = declRefExpr->getSourceRange();
} else {
maVarUsesMap[varDecl]++;
}
return true;
}
loplugin::Plugin::Registration< OnceVar > X("oncevar", false);
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */