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//===--- TransGCAttrs.cpp - Transformations to ARC mode --------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "Transforms.h"
#include "Internals.h"
#include "clang/AST/ASTContext.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Lexer.h"
#include "clang/Sema/SemaDiagnostic.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/TinyPtrVector.h"
#include "llvm/Support/SaveAndRestore.h"
using namespace clang;
using namespace arcmt;
using namespace trans;
namespace {
/// Collects all the places where GC attributes __strong/__weak occur.
class GCAttrsCollector : public RecursiveASTVisitor<GCAttrsCollector> {
MigrationContext &MigrateCtx;
bool FullyMigratable;
std::vector<ObjCPropertyDecl *> &AllProps;
typedef RecursiveASTVisitor<GCAttrsCollector> base;
public:
GCAttrsCollector(MigrationContext &ctx,
std::vector<ObjCPropertyDecl *> &AllProps)
: MigrateCtx(ctx), FullyMigratable(false),
AllProps(AllProps) { }
bool shouldWalkTypesOfTypeLocs() const { return false; }
bool VisitAttributedTypeLoc(AttributedTypeLoc TL) {
handleAttr(TL);
return true;
}
bool TraverseDecl(Decl *D) {
if (!D || D->isImplicit())
return true;
SaveAndRestore<bool> Save(FullyMigratable, isMigratable(D));
if (ObjCPropertyDecl *PropD = dyn_cast<ObjCPropertyDecl>(D)) {
lookForAttribute(PropD, PropD->getTypeSourceInfo());
AllProps.push_back(PropD);
} else if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
lookForAttribute(DD, DD->getTypeSourceInfo());
}
return base::TraverseDecl(D);
}
void lookForAttribute(Decl *D, TypeSourceInfo *TInfo) {
if (!TInfo)
return;
TypeLoc TL = TInfo->getTypeLoc();
while (TL) {
if (QualifiedTypeLoc QL = TL.getAs<QualifiedTypeLoc>()) {
TL = QL.getUnqualifiedLoc();
} else if (AttributedTypeLoc Attr = TL.getAs<AttributedTypeLoc>()) {
if (handleAttr(Attr, D))
break;
TL = Attr.getModifiedLoc();
} else if (MacroQualifiedTypeLoc MDTL =
TL.getAs<MacroQualifiedTypeLoc>()) {
TL = MDTL.getInnerLoc();
} else if (ArrayTypeLoc Arr = TL.getAs<ArrayTypeLoc>()) {
TL = Arr.getElementLoc();
} else if (PointerTypeLoc PT = TL.getAs<PointerTypeLoc>()) {
TL = PT.getPointeeLoc();
} else if (ReferenceTypeLoc RT = TL.getAs<ReferenceTypeLoc>())
TL = RT.getPointeeLoc();
else
break;
}
}
bool handleAttr(AttributedTypeLoc TL, Decl *D = nullptr) {
auto *OwnershipAttr = TL.getAttrAs<ObjCOwnershipAttr>();
if (!OwnershipAttr)
return false;
SourceLocation Loc = OwnershipAttr->getLocation();
SourceLocation OrigLoc = Loc;
if (MigrateCtx.AttrSet.count(OrigLoc))
return true;
ASTContext &Ctx = MigrateCtx.Pass.Ctx;
SourceManager &SM = Ctx.getSourceManager();
if (Loc.isMacroID())
Loc = SM.getImmediateExpansionRange(Loc).getBegin();
StringRef Spell = OwnershipAttr->getKind()->getName();
MigrationContext::GCAttrOccurrence::AttrKind Kind;
if (Spell == "strong")
Kind = MigrationContext::GCAttrOccurrence::Strong;
else if (Spell == "weak")
Kind = MigrationContext::GCAttrOccurrence::Weak;
else
return false;
MigrateCtx.AttrSet.insert(OrigLoc);
MigrateCtx.GCAttrs.push_back(MigrationContext::GCAttrOccurrence());
MigrationContext::GCAttrOccurrence &Attr = MigrateCtx.GCAttrs.back();
Attr.Kind = Kind;
Attr.Loc = Loc;
Attr.ModifiedType = TL.getModifiedLoc().getType();
Attr.Dcl = D;
Attr.FullyMigratable = FullyMigratable;
return true;
}
bool isMigratable(Decl *D) {
if (isa<TranslationUnitDecl>(D))
return false;
if (isInMainFile(D))
return true;
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
return FD->hasBody();
if (ObjCContainerDecl *ContD = dyn_cast<ObjCContainerDecl>(D))
return hasObjCImpl(ContD);
if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
for (const auto *MI : RD->methods()) {
if (MI->isOutOfLine())
return true;
}
return false;
}
return isMigratable(cast<Decl>(D->getDeclContext()));
}
static bool hasObjCImpl(Decl *D) {
if (!D)
return false;
if (ObjCContainerDecl *ContD = dyn_cast<ObjCContainerDecl>(D)) {
if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(ContD))
return ID->getImplementation() != nullptr;
if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(ContD))
return CD->getImplementation() != nullptr;
return isa<ObjCImplDecl>(ContD);
}
return false;
}
bool isInMainFile(Decl *D) {
if (!D)
return false;
for (auto I : D->redecls())
if (!isInMainFile(I->getLocation()))
return false;
return true;
}
bool isInMainFile(SourceLocation Loc) {
if (Loc.isInvalid())
return false;
SourceManager &SM = MigrateCtx.Pass.Ctx.getSourceManager();
return SM.isInFileID(SM.getExpansionLoc(Loc), SM.getMainFileID());
}
};
} // anonymous namespace
static void errorForGCAttrsOnNonObjC(MigrationContext &MigrateCtx) {
TransformActions &TA = MigrateCtx.Pass.TA;
for (unsigned i = 0, e = MigrateCtx.GCAttrs.size(); i != e; ++i) {
MigrationContext::GCAttrOccurrence &Attr = MigrateCtx.GCAttrs[i];
if (Attr.FullyMigratable && Attr.Dcl) {
if (Attr.ModifiedType.isNull())
continue;
if (!Attr.ModifiedType->isObjCRetainableType()) {
TA.reportError("GC managed memory will become unmanaged in ARC",
Attr.Loc);
}
}
}
}
static void checkWeakGCAttrs(MigrationContext &MigrateCtx) {
TransformActions &TA = MigrateCtx.Pass.TA;
for (unsigned i = 0, e = MigrateCtx.GCAttrs.size(); i != e; ++i) {
MigrationContext::GCAttrOccurrence &Attr = MigrateCtx.GCAttrs[i];
if (Attr.Kind == MigrationContext::GCAttrOccurrence::Weak) {
if (Attr.ModifiedType.isNull() ||
!Attr.ModifiedType->isObjCRetainableType())
continue;
if (!canApplyWeak(MigrateCtx.Pass.Ctx, Attr.ModifiedType,
/*AllowOnUnknownClass=*/true)) {
Transaction Trans(TA);
if (!MigrateCtx.RemovedAttrSet.count(Attr.Loc))
TA.replaceText(Attr.Loc, "__weak", "__unsafe_unretained");
TA.clearDiagnostic(diag::err_arc_weak_no_runtime,
diag::err_arc_unsupported_weak_class,
Attr.Loc);
}
}
}
}
typedef llvm::TinyPtrVector<ObjCPropertyDecl *> IndivPropsTy;
static void checkAllAtProps(MigrationContext &MigrateCtx,
SourceLocation AtLoc,
IndivPropsTy &IndProps) {
if (IndProps.empty())
return;
for (IndivPropsTy::iterator
PI = IndProps.begin(), PE = IndProps.end(); PI != PE; ++PI) {
QualType T = (*PI)->getType();
if (T.isNull() || !T->isObjCRetainableType())
return;
}
SmallVector<std::pair<AttributedTypeLoc, ObjCPropertyDecl *>, 4> ATLs;
bool hasWeak = false, hasStrong = false;
ObjCPropertyAttribute::Kind Attrs = ObjCPropertyAttribute::kind_noattr;
for (IndivPropsTy::iterator
PI = IndProps.begin(), PE = IndProps.end(); PI != PE; ++PI) {
ObjCPropertyDecl *PD = *PI;
Attrs = PD->getPropertyAttributesAsWritten();
TypeSourceInfo *TInfo = PD->getTypeSourceInfo();
if (!TInfo)
return;
TypeLoc TL = TInfo->getTypeLoc();
if (AttributedTypeLoc ATL =
TL.getAs<AttributedTypeLoc>()) {
ATLs.push_back(std::make_pair(ATL, PD));
if (TInfo->getType().getObjCLifetime() == Qualifiers::OCL_Weak) {
hasWeak = true;
} else if (TInfo->getType().getObjCLifetime() == Qualifiers::OCL_Strong)
hasStrong = true;
else
return;
}
}
if (ATLs.empty())
return;
if (hasWeak && hasStrong)
return;
TransformActions &TA = MigrateCtx.Pass.TA;
Transaction Trans(TA);
if (GCAttrsCollector::hasObjCImpl(
cast<Decl>(IndProps.front()->getDeclContext()))) {
if (hasWeak)
MigrateCtx.AtPropsWeak.insert(AtLoc);
} else {
StringRef toAttr = "strong";
if (hasWeak) {
if (canApplyWeak(MigrateCtx.Pass.Ctx, IndProps.front()->getType(),
/*AllowOnUnknownClass=*/true))
toAttr = "weak";
else
toAttr = "unsafe_unretained";
}
if (Attrs & ObjCPropertyAttribute::kind_assign)
MigrateCtx.rewritePropertyAttribute("assign", toAttr, AtLoc);
else
MigrateCtx.addPropertyAttribute(toAttr, AtLoc);
}
for (unsigned i = 0, e = ATLs.size(); i != e; ++i) {
SourceLocation Loc = ATLs[i].first.getAttr()->getLocation();
if (Loc.isMacroID())
Loc = MigrateCtx.Pass.Ctx.getSourceManager()
.getImmediateExpansionRange(Loc)
.getBegin();
TA.remove(Loc);
TA.clearDiagnostic(diag::err_objc_property_attr_mutually_exclusive, AtLoc);
TA.clearDiagnostic(diag::err_arc_inconsistent_property_ownership,
ATLs[i].second->getLocation());
MigrateCtx.RemovedAttrSet.insert(Loc);
}
}
static void checkAllProps(MigrationContext &MigrateCtx,
std::vector<ObjCPropertyDecl *> &AllProps) {
typedef llvm::TinyPtrVector<ObjCPropertyDecl *> IndivPropsTy;
llvm::DenseMap<SourceLocation, IndivPropsTy> AtProps;
for (unsigned i = 0, e = AllProps.size(); i != e; ++i) {
ObjCPropertyDecl *PD = AllProps[i];
if (PD->getPropertyAttributesAsWritten() &
(ObjCPropertyAttribute::kind_assign |
ObjCPropertyAttribute::kind_readonly)) {
SourceLocation AtLoc = PD->getAtLoc();
if (AtLoc.isInvalid())
continue;
AtProps[AtLoc].push_back(PD);
}
}
for (auto I = AtProps.begin(), E = AtProps.end(); I != E; ++I) {
SourceLocation AtLoc = I->first;
IndivPropsTy &IndProps = I->second;
checkAllAtProps(MigrateCtx, AtLoc, IndProps);
}
}
void GCAttrsTraverser::traverseTU(MigrationContext &MigrateCtx) {
std::vector<ObjCPropertyDecl *> AllProps;
GCAttrsCollector(MigrateCtx, AllProps).TraverseDecl(
MigrateCtx.Pass.Ctx.getTranslationUnitDecl());
errorForGCAttrsOnNonObjC(MigrateCtx);
checkAllProps(MigrateCtx, AllProps);
checkWeakGCAttrs(MigrateCtx);
}
void MigrationContext::dumpGCAttrs() {
llvm::errs() << "\n################\n";
for (unsigned i = 0, e = GCAttrs.size(); i != e; ++i) {
GCAttrOccurrence &Attr = GCAttrs[i];
llvm::errs() << "KIND: "
<< (Attr.Kind == GCAttrOccurrence::Strong ? "strong" : "weak");
llvm::errs() << "\nLOC: ";
Attr.Loc.print(llvm::errs(), Pass.Ctx.getSourceManager());
llvm::errs() << "\nTYPE: ";
Attr.ModifiedType.dump();
if (Attr.Dcl) {
llvm::errs() << "DECL:\n";
Attr.Dcl->dump();
} else {
llvm::errs() << "DECL: NONE";
}
llvm::errs() << "\nMIGRATABLE: " << Attr.FullyMigratable;
llvm::errs() << "\n----------------\n";
}
llvm::errs() << "\n################\n";
}