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//===--- TransAllocCopyWithZone.cpp - Tranformations to ARC mode ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// rewriteAllocCopyWithZone:
//
// Calls to +allocWithZone/-copyWithZone/-mutableCopyWithZone are changed to
// +alloc/-copy/-mutableCopy if we can safely remove the given parameter.
//
// Foo *foo1 = [[Foo allocWithZone:[self zone]] init];
// ---->
// Foo *foo1 = [[Foo alloc] init];
//
//===----------------------------------------------------------------------===//
#include "Transforms.h"
#include "Internals.h"
#include "clang/Sema/SemaDiagnostic.h"
using namespace clang;
using namespace arcmt;
using namespace trans;
using llvm::StringRef;
namespace {
class AllocCopyWithZoneRewriter :
public RecursiveASTVisitor<AllocCopyWithZoneRewriter> {
Decl *Dcl;
Stmt *Body;
MigrationPass &Pass;
Selector allocWithZoneSel;
Selector copyWithZoneSel;
Selector mutableCopyWithZoneSel;
Selector zoneSel;
IdentifierInfo *NSZoneII;
std::vector<DeclStmt *> NSZoneVars;
std::vector<Expr *> Removals;
public:
AllocCopyWithZoneRewriter(Decl *D, MigrationPass &pass)
: Dcl(D), Body(0), Pass(pass) {
SelectorTable &sels = pass.Ctx.Selectors;
IdentifierTable &ids = pass.Ctx.Idents;
allocWithZoneSel = sels.getUnarySelector(&ids.get("allocWithZone"));
copyWithZoneSel = sels.getUnarySelector(&ids.get("copyWithZone"));
mutableCopyWithZoneSel = sels.getUnarySelector(
&ids.get("mutableCopyWithZone"));
zoneSel = sels.getNullarySelector(&ids.get("zone"));
NSZoneII = &ids.get("_NSZone");
}
void transformBody(Stmt *body) {
Body = body;
// Don't change allocWithZone/copyWithZone messages inside
// custom implementations of such methods, it can lead to infinite loops.
if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(Dcl)) {
Selector sel = MD->getSelector();
if (sel == allocWithZoneSel ||
sel == copyWithZoneSel ||
sel == mutableCopyWithZoneSel ||
sel == zoneSel)
return;
}
TraverseStmt(body);
}
~AllocCopyWithZoneRewriter() {
for (std::vector<DeclStmt *>::reverse_iterator
I = NSZoneVars.rbegin(), E = NSZoneVars.rend(); I != E; ++I) {
DeclStmt *DS = *I;
DeclGroupRef group = DS->getDeclGroup();
std::vector<Expr *> varRemovals = Removals;
bool areAllVarsUnused = true;
for (std::reverse_iterator<DeclGroupRef::iterator>
DI(group.end()), DE(group.begin()); DI != DE; ++DI) {
VarDecl *VD = cast<VarDecl>(*DI);
if (isNSZoneVarUsed(VD, varRemovals)) {
areAllVarsUnused = false;
break;
}
varRemovals.push_back(VD->getInit());
}
if (areAllVarsUnused) {
Transaction Trans(Pass.TA);
clearUnavailableDiags(DS);
Pass.TA.removeStmt(DS);
Removals.swap(varRemovals);
}
}
}
bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
if (!isAllocCopyWithZoneCall(E))
return true;
Expr *arg = E->getArg(0);
if (paramToAllocWithZoneHasSideEffects(arg))
return true;
Pass.TA.startTransaction();
clearUnavailableDiags(arg);
Pass.TA.clearDiagnostic(diag::err_unavailable_message,
E->getReceiverRange().getBegin());
Pass.TA.remove(SourceRange(E->getSelectorLoc(), arg->getLocEnd()));
StringRef rewrite;
if (E->getSelector() == allocWithZoneSel)
rewrite = "alloc";
else if (E->getSelector() == copyWithZoneSel)
rewrite = "copy";
else {
assert(E->getSelector() == mutableCopyWithZoneSel);
rewrite = "mutableCopy";
}
Pass.TA.insert(E->getSelectorLoc(), rewrite);
bool failed = Pass.TA.commitTransaction();
if (!failed)
Removals.push_back(arg);
return true;
}
bool VisitDeclStmt(DeclStmt *DS) {
DeclGroupRef group = DS->getDeclGroup();
if (group.begin() == group.end())
return true;
for (DeclGroupRef::iterator
DI = group.begin(), DE = group.end(); DI != DE; ++DI)
if (!isRemovableNSZoneVar(*DI))
return true;
NSZoneVars.push_back(DS);
return true;
}
private:
bool isRemovableNSZoneVar(Decl *D) {
if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (isNSZone(VD->getType()))
return !paramToAllocWithZoneHasSideEffects(VD->getInit());
}
return false;
}
bool isNSZone(RecordDecl *RD) {
return RD && RD->getIdentifier() == NSZoneII;
}
bool isNSZone(QualType Ty) {
QualType pointee = Ty->getPointeeType();
if (pointee.isNull())
return false;
if (const RecordType *recT = pointee->getAsStructureType())
return isNSZone(recT->getDecl());
return false;
}
bool isNSZoneVarUsed(VarDecl *D, std::vector<Expr *> &removals) {
ExprSet refs;
collectRefs(D, Body, refs);
clearRefsIn(removals.begin(), removals.end(), refs);
return !refs.empty();
}
bool isAllocCopyWithZoneCall(ObjCMessageExpr *E) {
if (E->getNumArgs() == 1 &&
E->getSelector() == allocWithZoneSel &&
(E->isClassMessage() ||
Pass.TA.hasDiagnostic(diag::err_unavailable_message,
E->getReceiverRange().getBegin())))
return true;
return E->isInstanceMessage() &&
E->getNumArgs() == 1 &&
(E->getSelector() == copyWithZoneSel ||
E->getSelector() == mutableCopyWithZoneSel);
}
bool isZoneCall(ObjCMessageExpr *E) {
return E->isInstanceMessage() &&
E->getNumArgs() == 0 &&
E->getSelector() == zoneSel;
}
bool paramToAllocWithZoneHasSideEffects(Expr *E) {
if (!hasSideEffects(E, Pass.Ctx))
return false;
E = E->IgnoreParenCasts();
ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E);
if (!ME)
return true;
if (!isZoneCall(ME))
return true;
return hasSideEffects(ME->getInstanceReceiver(), Pass.Ctx);
}
void clearUnavailableDiags(Stmt *S) {
if (S)
Pass.TA.clearDiagnostic(diag::err_unavailable,
diag::err_unavailable_message,
S->getSourceRange());
}
};
} // end anonymous namespace
void trans::rewriteAllocCopyWithZone(MigrationPass &pass) {
BodyTransform<AllocCopyWithZoneRewriter> trans(pass);
trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
}
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