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//===--- Transforms.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/AST/RecursiveASTVisitor.h"
#include "clang/Analysis/DomainSpecific/CocoaConventions.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/Sema.h"
using namespace clang;
using namespace arcmt;
using namespace trans;
ASTTraverser::~ASTTraverser() { }
bool MigrationPass::CFBridgingFunctionsDefined() {
if (!EnableCFBridgeFns.hasValue())
EnableCFBridgeFns = SemaRef.isKnownName("CFBridgingRetain") &&
SemaRef.isKnownName("CFBridgingRelease");
return *EnableCFBridgeFns;
}
//===----------------------------------------------------------------------===//
// Helpers.
//===----------------------------------------------------------------------===//
bool trans::canApplyWeak(ASTContext &Ctx, QualType type,
bool AllowOnUnknownClass) {
if (!Ctx.getLangOpts().ObjCWeakRuntime)
return false;
QualType T = type;
if (T.isNull())
return false;
// iOS is always safe to use 'weak'.
if (Ctx.getTargetInfo().getTriple().isiOS() ||
Ctx.getTargetInfo().getTriple().isWatchOS())
AllowOnUnknownClass = true;
while (const PointerType *ptr = T->getAs<PointerType>())
T = ptr->getPointeeType();
if (const ObjCObjectPointerType *ObjT = T->getAs<ObjCObjectPointerType>()) {
ObjCInterfaceDecl *Class = ObjT->getInterfaceDecl();
if (!AllowOnUnknownClass && (!Class || Class->getName() == "NSObject"))
return false; // id/NSObject is not safe for weak.
if (!AllowOnUnknownClass && !Class->hasDefinition())
return false; // forward classes are not verifiable, therefore not safe.
if (Class && Class->isArcWeakrefUnavailable())
return false;
}
return true;
}
bool trans::isPlusOneAssign(const BinaryOperator *E) {
if (E->getOpcode() != BO_Assign)
return false;
return isPlusOne(E->getRHS());
}
bool trans::isPlusOne(const Expr *E) {
if (!E)
return false;
if (const FullExpr *FE = dyn_cast<FullExpr>(E))
E = FE->getSubExpr();
if (const ObjCMessageExpr *
ME = dyn_cast<ObjCMessageExpr>(E->IgnoreParenCasts()))
if (ME->getMethodFamily() == OMF_retain)
return true;
if (const CallExpr *
callE = dyn_cast<CallExpr>(E->IgnoreParenCasts())) {
if (const FunctionDecl *FD = callE->getDirectCallee()) {
if (FD->hasAttr<CFReturnsRetainedAttr>())
return true;
if (FD->isGlobal() &&
FD->getIdentifier() &&
FD->getParent()->isTranslationUnit() &&
FD->isExternallyVisible() &&
ento::cocoa::isRefType(callE->getType(), "CF",
FD->getIdentifier()->getName())) {
StringRef fname = FD->getIdentifier()->getName();
if (fname.endswith("Retain") ||
fname.find("Create") != StringRef::npos ||
fname.find("Copy") != StringRef::npos) {
return true;
}
}
}
}
const ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E);
while (implCE && implCE->getCastKind() == CK_BitCast)
implCE = dyn_cast<ImplicitCastExpr>(implCE->getSubExpr());
return implCE && implCE->getCastKind() == CK_ARCConsumeObject;
}
/// 'Loc' is the end of a statement range. This returns the location
/// immediately after the semicolon following the statement.
/// If no semicolon is found or the location is inside a macro, the returned
/// source location will be invalid.
SourceLocation trans::findLocationAfterSemi(SourceLocation loc,
ASTContext &Ctx, bool IsDecl) {
SourceLocation SemiLoc = findSemiAfterLocation(loc, Ctx, IsDecl);
if (SemiLoc.isInvalid())
return SourceLocation();
return SemiLoc.getLocWithOffset(1);
}
/// \arg Loc is the end of a statement range. This returns the location
/// of the semicolon following the statement.
/// If no semicolon is found or the location is inside a macro, the returned
/// source location will be invalid.
SourceLocation trans::findSemiAfterLocation(SourceLocation loc,
ASTContext &Ctx,
bool IsDecl) {
SourceManager &SM = Ctx.getSourceManager();
if (loc.isMacroID()) {
if (!Lexer::isAtEndOfMacroExpansion(loc, SM, Ctx.getLangOpts(), &loc))
return SourceLocation();
}
loc = Lexer::getLocForEndOfToken(loc, /*Offset=*/0, SM, Ctx.getLangOpts());
// Break down the source location.
std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(loc);
// Try to load the file buffer.
bool invalidTemp = false;
StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
if (invalidTemp)
return SourceLocation();
const char *tokenBegin = file.data() + locInfo.second;
// Lex from the start of the given location.
Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
Ctx.getLangOpts(),
file.begin(), tokenBegin, file.end());
Token tok;
lexer.LexFromRawLexer(tok);
if (tok.isNot(tok::semi)) {
if (!IsDecl)
return SourceLocation();
// Declaration may be followed with other tokens; such as an __attribute,
// before ending with a semicolon.
return findSemiAfterLocation(tok.getLocation(), Ctx, /*IsDecl*/true);
}
return tok.getLocation();
}
bool trans::hasSideEffects(Expr *E, ASTContext &Ctx) {
if (!E || !E->HasSideEffects(Ctx))
return false;
E = E->IgnoreParenCasts();
ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E);
if (!ME)
return true;
switch (ME->getMethodFamily()) {
case OMF_autorelease:
case OMF_dealloc:
case OMF_release:
case OMF_retain:
switch (ME->getReceiverKind()) {
case ObjCMessageExpr::SuperInstance:
return false;
case ObjCMessageExpr::Instance:
return hasSideEffects(ME->getInstanceReceiver(), Ctx);
default:
break;
}
break;
default:
break;
}
return true;
}
bool trans::isGlobalVar(Expr *E) {
E = E->IgnoreParenCasts();
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
return DRE->getDecl()->getDeclContext()->isFileContext() &&
DRE->getDecl()->isExternallyVisible();
if (ConditionalOperator *condOp = dyn_cast<ConditionalOperator>(E))
return isGlobalVar(condOp->getTrueExpr()) &&
isGlobalVar(condOp->getFalseExpr());
return false;
}
StringRef trans::getNilString(MigrationPass &Pass) {
return Pass.SemaRef.PP.isMacroDefined("nil") ? "nil" : "0";
}
namespace {
class ReferenceClear : public RecursiveASTVisitor<ReferenceClear> {
ExprSet &Refs;
public:
ReferenceClear(ExprSet &refs) : Refs(refs) { }
bool VisitDeclRefExpr(DeclRefExpr *E) { Refs.erase(E); return true; }
};
class ReferenceCollector : public RecursiveASTVisitor<ReferenceCollector> {
ValueDecl *Dcl;
ExprSet &Refs;
public:
ReferenceCollector(ValueDecl *D, ExprSet &refs)
: Dcl(D), Refs(refs) { }
bool VisitDeclRefExpr(DeclRefExpr *E) {
if (E->getDecl() == Dcl)
Refs.insert(E);
return true;
}
};
class RemovablesCollector : public RecursiveASTVisitor<RemovablesCollector> {
ExprSet &Removables;
public:
RemovablesCollector(ExprSet &removables)
: Removables(removables) { }
bool shouldWalkTypesOfTypeLocs() const { return false; }
bool TraverseStmtExpr(StmtExpr *E) {
CompoundStmt *S = E->getSubStmt();
for (CompoundStmt::body_iterator
I = S->body_begin(), E = S->body_end(); I != E; ++I) {
if (I != E - 1)
mark(*I);
TraverseStmt(*I);
}
return true;
}
bool VisitCompoundStmt(CompoundStmt *S) {
for (auto *I : S->body())
mark(I);
return true;
}
bool VisitIfStmt(IfStmt *S) {
mark(S->getThen());
mark(S->getElse());
return true;
}
bool VisitWhileStmt(WhileStmt *S) {
mark(S->getBody());
return true;
}
bool VisitDoStmt(DoStmt *S) {
mark(S->getBody());
return true;
}
bool VisitForStmt(ForStmt *S) {
mark(S->getInit());
mark(S->getInc());
mark(S->getBody());
return true;
}
private:
void mark(Stmt *S) {
if (!S) return;
while (auto *Label = dyn_cast<LabelStmt>(S))
S = Label->getSubStmt();
if (auto *E = dyn_cast<Expr>(S))
S = E->IgnoreImplicit();
if (auto *E = dyn_cast<Expr>(S))
Removables.insert(E);
}
};
} // end anonymous namespace
void trans::clearRefsIn(Stmt *S, ExprSet &refs) {
ReferenceClear(refs).TraverseStmt(S);
}
void trans::collectRefs(ValueDecl *D, Stmt *S, ExprSet &refs) {
ReferenceCollector(D, refs).TraverseStmt(S);
}
void trans::collectRemovables(Stmt *S, ExprSet &exprs) {
RemovablesCollector(exprs).TraverseStmt(S);
}
//===----------------------------------------------------------------------===//
// MigrationContext
//===----------------------------------------------------------------------===//
namespace {
class ASTTransform : public RecursiveASTVisitor<ASTTransform> {
MigrationContext &MigrateCtx;
typedef RecursiveASTVisitor<ASTTransform> base;
public:
ASTTransform(MigrationContext &MigrateCtx) : MigrateCtx(MigrateCtx) { }
bool shouldWalkTypesOfTypeLocs() const { return false; }
bool TraverseObjCImplementationDecl(ObjCImplementationDecl *D) {
ObjCImplementationContext ImplCtx(MigrateCtx, D);
for (MigrationContext::traverser_iterator
I = MigrateCtx.traversers_begin(),
E = MigrateCtx.traversers_end(); I != E; ++I)
(*I)->traverseObjCImplementation(ImplCtx);
return base::TraverseObjCImplementationDecl(D);
}
bool TraverseStmt(Stmt *rootS) {
if (!rootS)
return true;
BodyContext BodyCtx(MigrateCtx, rootS);
for (MigrationContext::traverser_iterator
I = MigrateCtx.traversers_begin(),
E = MigrateCtx.traversers_end(); I != E; ++I)
(*I)->traverseBody(BodyCtx);
return true;
}
};
}
MigrationContext::~MigrationContext() {
for (traverser_iterator
I = traversers_begin(), E = traversers_end(); I != E; ++I)
delete *I;
}
bool MigrationContext::isGCOwnedNonObjC(QualType T) {
while (!T.isNull()) {
if (const AttributedType *AttrT = T->getAs<AttributedType>()) {
if (AttrT->getAttrKind() == attr::ObjCOwnership)
return !AttrT->getModifiedType()->isObjCRetainableType();
}
if (T->isArrayType())
T = Pass.Ctx.getBaseElementType(T);
else if (const PointerType *PT = T->getAs<PointerType>())
T = PT->getPointeeType();
else if (const ReferenceType *RT = T->getAs<ReferenceType>())
T = RT->getPointeeType();
else
break;
}
return false;
}
bool MigrationContext::rewritePropertyAttribute(StringRef fromAttr,
StringRef toAttr,
SourceLocation atLoc) {
if (atLoc.isMacroID())
return false;
SourceManager &SM = Pass.Ctx.getSourceManager();
// Break down the source location.
std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(atLoc);
// Try to load the file buffer.
bool invalidTemp = false;
StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
if (invalidTemp)
return false;
const char *tokenBegin = file.data() + locInfo.second;
// Lex from the start of the given location.
Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
Pass.Ctx.getLangOpts(),
file.begin(), tokenBegin, file.end());
Token tok;
lexer.LexFromRawLexer(tok);
if (tok.isNot(tok::at)) return false;
lexer.LexFromRawLexer(tok);
if (tok.isNot(tok::raw_identifier)) return false;
if (tok.getRawIdentifier() != "property")
return false;
lexer.LexFromRawLexer(tok);
if (tok.isNot(tok::l_paren)) return false;
Token BeforeTok = tok;
Token AfterTok;
AfterTok.startToken();
SourceLocation AttrLoc;
lexer.LexFromRawLexer(tok);
if (tok.is(tok::r_paren))
return false;
while (1) {
if (tok.isNot(tok::raw_identifier)) return false;
if (tok.getRawIdentifier() == fromAttr) {
if (!toAttr.empty()) {
Pass.TA.replaceText(tok.getLocation(), fromAttr, toAttr);
return true;
}
// We want to remove the attribute.
AttrLoc = tok.getLocation();
}
do {
lexer.LexFromRawLexer(tok);
if (AttrLoc.isValid() && AfterTok.is(tok::unknown))
AfterTok = tok;
} while (tok.isNot(tok::comma) && tok.isNot(tok::r_paren));
if (tok.is(tok::r_paren))
break;
if (AttrLoc.isInvalid())
BeforeTok = tok;
lexer.LexFromRawLexer(tok);
}
if (toAttr.empty() && AttrLoc.isValid() && AfterTok.isNot(tok::unknown)) {
// We want to remove the attribute.
if (BeforeTok.is(tok::l_paren) && AfterTok.is(tok::r_paren)) {
Pass.TA.remove(SourceRange(BeforeTok.getLocation(),
AfterTok.getLocation()));
} else if (BeforeTok.is(tok::l_paren) && AfterTok.is(tok::comma)) {
Pass.TA.remove(SourceRange(AttrLoc, AfterTok.getLocation()));
} else {
Pass.TA.remove(SourceRange(BeforeTok.getLocation(), AttrLoc));
}
return true;
}
return false;
}
bool MigrationContext::addPropertyAttribute(StringRef attr,
SourceLocation atLoc) {
if (atLoc.isMacroID())
return false;
SourceManager &SM = Pass.Ctx.getSourceManager();
// Break down the source location.
std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(atLoc);
// Try to load the file buffer.
bool invalidTemp = false;
StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
if (invalidTemp)
return false;
const char *tokenBegin = file.data() + locInfo.second;
// Lex from the start of the given location.
Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
Pass.Ctx.getLangOpts(),
file.begin(), tokenBegin, file.end());
Token tok;
lexer.LexFromRawLexer(tok);
if (tok.isNot(tok::at)) return false;
lexer.LexFromRawLexer(tok);
if (tok.isNot(tok::raw_identifier)) return false;
if (tok.getRawIdentifier() != "property")
return false;
lexer.LexFromRawLexer(tok);
if (tok.isNot(tok::l_paren)) {
Pass.TA.insert(tok.getLocation(), std::string("(") + attr.str() + ") ");
return true;
}
lexer.LexFromRawLexer(tok);
if (tok.is(tok::r_paren)) {
Pass.TA.insert(tok.getLocation(), attr);
return true;
}
if (tok.isNot(tok::raw_identifier)) return false;
Pass.TA.insert(tok.getLocation(), std::string(attr) + ", ");
return true;
}
void MigrationContext::traverse(TranslationUnitDecl *TU) {
for (traverser_iterator
I = traversers_begin(), E = traversers_end(); I != E; ++I)
(*I)->traverseTU(*this);
ASTTransform(*this).TraverseDecl(TU);
}
static void GCRewriteFinalize(MigrationPass &pass) {
ASTContext &Ctx = pass.Ctx;
TransformActions &TA = pass.TA;
DeclContext *DC = Ctx.getTranslationUnitDecl();
Selector FinalizeSel =
Ctx.Selectors.getNullarySelector(&pass.Ctx.Idents.get("finalize"));
typedef DeclContext::specific_decl_iterator<ObjCImplementationDecl>
impl_iterator;
for (impl_iterator I = impl_iterator(DC->decls_begin()),
E = impl_iterator(DC->decls_end()); I != E; ++I) {
for (const auto *MD : I->instance_methods()) {
if (!MD->hasBody())
continue;
if (MD->isInstanceMethod() && MD->getSelector() == FinalizeSel) {
const ObjCMethodDecl *FinalizeM = MD;
Transaction Trans(TA);
TA.insert(FinalizeM->getSourceRange().getBegin(),
"#if !__has_feature(objc_arc)\n");
CharSourceRange::getTokenRange(FinalizeM->getSourceRange());
const SourceManager &SM = pass.Ctx.getSourceManager();
const LangOptions &LangOpts = pass.Ctx.getLangOpts();
bool Invalid;
std::string str = "\n#endif\n";
str += Lexer::getSourceText(
CharSourceRange::getTokenRange(FinalizeM->getSourceRange()),
SM, LangOpts, &Invalid);
TA.insertAfterToken(FinalizeM->getSourceRange().getEnd(), str);
break;
}
}
}
}
//===----------------------------------------------------------------------===//
// getAllTransformations.
//===----------------------------------------------------------------------===//
static void traverseAST(MigrationPass &pass) {
MigrationContext MigrateCtx(pass);
if (pass.isGCMigration()) {
MigrateCtx.addTraverser(new GCCollectableCallsTraverser);
MigrateCtx.addTraverser(new GCAttrsTraverser());
}
MigrateCtx.addTraverser(new PropertyRewriteTraverser());
MigrateCtx.addTraverser(new BlockObjCVariableTraverser());
MigrateCtx.addTraverser(new ProtectedScopeTraverser());
MigrateCtx.traverse(pass.Ctx.getTranslationUnitDecl());
}
static void independentTransforms(MigrationPass &pass) {
rewriteAutoreleasePool(pass);
removeRetainReleaseDeallocFinalize(pass);
rewriteUnusedInitDelegate(pass);
removeZeroOutPropsInDeallocFinalize(pass);
makeAssignARCSafe(pass);
rewriteUnbridgedCasts(pass);
checkAPIUses(pass);
traverseAST(pass);
}
std::vector<TransformFn> arcmt::getAllTransformations(
LangOptions::GCMode OrigGCMode,
bool NoFinalizeRemoval) {
std::vector<TransformFn> transforms;
if (OrigGCMode == LangOptions::GCOnly && NoFinalizeRemoval)
transforms.push_back(GCRewriteFinalize);
transforms.push_back(independentTransforms);
// This depends on previous transformations removing various expressions.
transforms.push_back(removeEmptyStatementsAndDeallocFinalize);
return transforms;
}