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-rw-r--r--clang/lib/ARCMigrate/TransAutoreleasePool.cpp434
1 files changed, 434 insertions, 0 deletions
diff --git a/clang/lib/ARCMigrate/TransAutoreleasePool.cpp b/clang/lib/ARCMigrate/TransAutoreleasePool.cpp
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--- /dev/null
+++ b/clang/lib/ARCMigrate/TransAutoreleasePool.cpp
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+//===--- TransAutoreleasePool.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.
+//
+//===----------------------------------------------------------------------===//
+//
+// rewriteAutoreleasePool:
+//
+// Calls to NSAutoreleasePools will be rewritten as an @autorelease scope.
+//
+// NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+// ...
+// [pool release];
+// ---->
+// @autorelease {
+// ...
+// }
+//
+// An NSAutoreleasePool will not be touched if:
+// - There is not a corresponding -release/-drain in the same scope
+// - Not all references of the NSAutoreleasePool variable can be removed
+// - There is a variable that is declared inside the intended @autorelease scope
+// which is also used outside it.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Transforms.h"
+#include "Internals.h"
+#include "clang/Sema/SemaDiagnostic.h"
+#include "clang/Basic/SourceManager.h"
+#include <map>
+
+using namespace clang;
+using namespace arcmt;
+using namespace trans;
+
+namespace {
+
+class ReleaseCollector : public RecursiveASTVisitor<ReleaseCollector> {
+ Decl *Dcl;
+ SmallVectorImpl<ObjCMessageExpr *> &Releases;
+
+public:
+ ReleaseCollector(Decl *D, SmallVectorImpl<ObjCMessageExpr *> &releases)
+ : Dcl(D), Releases(releases) { }
+
+ bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
+ if (!E->isInstanceMessage())
+ return true;
+ if (E->getMethodFamily() != OMF_release)
+ return true;
+ Expr *instance = E->getInstanceReceiver()->IgnoreParenCasts();
+ if (DeclRefExpr *DE = dyn_cast<DeclRefExpr>(instance)) {
+ if (DE->getDecl() == Dcl)
+ Releases.push_back(E);
+ }
+ return true;
+ }
+};
+
+}
+
+namespace {
+
+class AutoreleasePoolRewriter
+ : public RecursiveASTVisitor<AutoreleasePoolRewriter> {
+public:
+ AutoreleasePoolRewriter(MigrationPass &pass)
+ : Body(0), Pass(pass) {
+ PoolII = &pass.Ctx.Idents.get("NSAutoreleasePool");
+ DrainSel = pass.Ctx.Selectors.getNullarySelector(
+ &pass.Ctx.Idents.get("drain"));
+ }
+
+ void transformBody(Stmt *body) {
+ Body = body;
+ TraverseStmt(body);
+ }
+
+ ~AutoreleasePoolRewriter() {
+ SmallVector<VarDecl *, 8> VarsToHandle;
+
+ for (std::map<VarDecl *, PoolVarInfo>::iterator
+ I = PoolVars.begin(), E = PoolVars.end(); I != E; ++I) {
+ VarDecl *var = I->first;
+ PoolVarInfo &info = I->second;
+
+ // Check that we can handle/rewrite all references of the pool.
+
+ clearRefsIn(info.Dcl, info.Refs);
+ for (SmallVectorImpl<PoolScope>::iterator
+ scpI = info.Scopes.begin(),
+ scpE = info.Scopes.end(); scpI != scpE; ++scpI) {
+ PoolScope &scope = *scpI;
+ clearRefsIn(*scope.Begin, info.Refs);
+ clearRefsIn(*scope.End, info.Refs);
+ clearRefsIn(scope.Releases.begin(), scope.Releases.end(), info.Refs);
+ }
+
+ // Even if one reference is not handled we will not do anything about that
+ // pool variable.
+ if (info.Refs.empty())
+ VarsToHandle.push_back(var);
+ }
+
+ for (unsigned i = 0, e = VarsToHandle.size(); i != e; ++i) {
+ PoolVarInfo &info = PoolVars[VarsToHandle[i]];
+
+ Transaction Trans(Pass.TA);
+
+ clearUnavailableDiags(info.Dcl);
+ Pass.TA.removeStmt(info.Dcl);
+
+ // Add "@autoreleasepool { }"
+ for (SmallVectorImpl<PoolScope>::iterator
+ scpI = info.Scopes.begin(),
+ scpE = info.Scopes.end(); scpI != scpE; ++scpI) {
+ PoolScope &scope = *scpI;
+ clearUnavailableDiags(*scope.Begin);
+ clearUnavailableDiags(*scope.End);
+ if (scope.IsFollowedBySimpleReturnStmt) {
+ // Include the return in the scope.
+ Pass.TA.replaceStmt(*scope.Begin, "@autoreleasepool {");
+ Pass.TA.removeStmt(*scope.End);
+ Stmt::child_iterator retI = scope.End;
+ ++retI;
+ SourceLocation afterSemi = findLocationAfterSemi((*retI)->getLocEnd(),
+ Pass.Ctx);
+ assert(afterSemi.isValid() &&
+ "Didn't we check before setting IsFollowedBySimpleReturnStmt "
+ "to true?");
+ Pass.TA.insertAfterToken(afterSemi, "\n}");
+ Pass.TA.increaseIndentation(
+ SourceRange(scope.getIndentedRange().getBegin(),
+ (*retI)->getLocEnd()),
+ scope.CompoundParent->getLocStart());
+ } else {
+ Pass.TA.replaceStmt(*scope.Begin, "@autoreleasepool {");
+ Pass.TA.replaceStmt(*scope.End, "}");
+ Pass.TA.increaseIndentation(scope.getIndentedRange(),
+ scope.CompoundParent->getLocStart());
+ }
+ }
+
+ // Remove rest of pool var references.
+ for (SmallVectorImpl<PoolScope>::iterator
+ scpI = info.Scopes.begin(),
+ scpE = info.Scopes.end(); scpI != scpE; ++scpI) {
+ PoolScope &scope = *scpI;
+ for (SmallVectorImpl<ObjCMessageExpr *>::iterator
+ relI = scope.Releases.begin(),
+ relE = scope.Releases.end(); relI != relE; ++relI) {
+ clearUnavailableDiags(*relI);
+ Pass.TA.removeStmt(*relI);
+ }
+ }
+ }
+ }
+
+ bool VisitCompoundStmt(CompoundStmt *S) {
+ SmallVector<PoolScope, 4> Scopes;
+
+ for (Stmt::child_iterator
+ I = S->body_begin(), E = S->body_end(); I != E; ++I) {
+ Stmt *child = getEssential(*I);
+ if (DeclStmt *DclS = dyn_cast<DeclStmt>(child)) {
+ if (DclS->isSingleDecl()) {
+ if (VarDecl *VD = dyn_cast<VarDecl>(DclS->getSingleDecl())) {
+ if (isNSAutoreleasePool(VD->getType())) {
+ PoolVarInfo &info = PoolVars[VD];
+ info.Dcl = DclS;
+ collectRefs(VD, S, info.Refs);
+ // Does this statement follow the pattern:
+ // NSAutoreleasePool * pool = [NSAutoreleasePool new];
+ if (isPoolCreation(VD->getInit())) {
+ Scopes.push_back(PoolScope());
+ Scopes.back().PoolVar = VD;
+ Scopes.back().CompoundParent = S;
+ Scopes.back().Begin = I;
+ }
+ }
+ }
+ }
+ } else if (BinaryOperator *bop = dyn_cast<BinaryOperator>(child)) {
+ if (DeclRefExpr *dref = dyn_cast<DeclRefExpr>(bop->getLHS())) {
+ if (VarDecl *VD = dyn_cast<VarDecl>(dref->getDecl())) {
+ // Does this statement follow the pattern:
+ // pool = [NSAutoreleasePool new];
+ if (isNSAutoreleasePool(VD->getType()) &&
+ isPoolCreation(bop->getRHS())) {
+ Scopes.push_back(PoolScope());
+ Scopes.back().PoolVar = VD;
+ Scopes.back().CompoundParent = S;
+ Scopes.back().Begin = I;
+ }
+ }
+ }
+ }
+
+ if (Scopes.empty())
+ continue;
+
+ if (isPoolDrain(Scopes.back().PoolVar, child)) {
+ PoolScope &scope = Scopes.back();
+ scope.End = I;
+ handlePoolScope(scope, S);
+ Scopes.pop_back();
+ }
+ }
+ return true;
+ }
+
+private:
+ void clearUnavailableDiags(Stmt *S) {
+ if (S)
+ Pass.TA.clearDiagnostic(diag::err_unavailable,
+ diag::err_unavailable_message,
+ S->getSourceRange());
+ }
+
+ struct PoolScope {
+ VarDecl *PoolVar;
+ CompoundStmt *CompoundParent;
+ Stmt::child_iterator Begin;
+ Stmt::child_iterator End;
+ bool IsFollowedBySimpleReturnStmt;
+ SmallVector<ObjCMessageExpr *, 4> Releases;
+
+ PoolScope() : PoolVar(0), CompoundParent(0), Begin(), End(),
+ IsFollowedBySimpleReturnStmt(false) { }
+
+ SourceRange getIndentedRange() const {
+ Stmt::child_iterator rangeS = Begin;
+ ++rangeS;
+ if (rangeS == End)
+ return SourceRange();
+ Stmt::child_iterator rangeE = Begin;
+ for (Stmt::child_iterator I = rangeS; I != End; ++I)
+ ++rangeE;
+ return SourceRange((*rangeS)->getLocStart(), (*rangeE)->getLocEnd());
+ }
+ };
+
+ class NameReferenceChecker : public RecursiveASTVisitor<NameReferenceChecker>{
+ ASTContext &Ctx;
+ SourceRange ScopeRange;
+ SourceLocation &referenceLoc, &declarationLoc;
+
+ public:
+ NameReferenceChecker(ASTContext &ctx, PoolScope &scope,
+ SourceLocation &referenceLoc,
+ SourceLocation &declarationLoc)
+ : Ctx(ctx), referenceLoc(referenceLoc),
+ declarationLoc(declarationLoc) {
+ ScopeRange = SourceRange((*scope.Begin)->getLocStart(),
+ (*scope.End)->getLocStart());
+ }
+
+ bool VisitDeclRefExpr(DeclRefExpr *E) {
+ return checkRef(E->getLocation(), E->getDecl()->getLocation());
+ }
+
+ bool VisitTypedefTypeLoc(TypedefTypeLoc TL) {
+ return checkRef(TL.getBeginLoc(), TL.getTypedefNameDecl()->getLocation());
+ }
+
+ bool VisitTagTypeLoc(TagTypeLoc TL) {
+ return checkRef(TL.getBeginLoc(), TL.getDecl()->getLocation());
+ }
+
+ private:
+ bool checkRef(SourceLocation refLoc, SourceLocation declLoc) {
+ if (isInScope(declLoc)) {
+ referenceLoc = refLoc;
+ declarationLoc = declLoc;
+ return false;
+ }
+ return true;
+ }
+
+ bool isInScope(SourceLocation loc) {
+ if (loc.isInvalid())
+ return false;
+
+ SourceManager &SM = Ctx.getSourceManager();
+ if (SM.isBeforeInTranslationUnit(loc, ScopeRange.getBegin()))
+ return false;
+ return SM.isBeforeInTranslationUnit(loc, ScopeRange.getEnd());
+ }
+ };
+
+ void handlePoolScope(PoolScope &scope, CompoundStmt *compoundS) {
+ // Check that all names declared inside the scope are not used
+ // outside the scope.
+ {
+ bool nameUsedOutsideScope = false;
+ SourceLocation referenceLoc, declarationLoc;
+ Stmt::child_iterator SI = scope.End, SE = compoundS->body_end();
+ ++SI;
+ // Check if the autoreleasepool scope is followed by a simple return
+ // statement, in which case we will include the return in the scope.
+ if (SI != SE)
+ if (ReturnStmt *retS = dyn_cast<ReturnStmt>(*SI))
+ if ((retS->getRetValue() == 0 ||
+ isa<DeclRefExpr>(retS->getRetValue()->IgnoreParenCasts())) &&
+ findLocationAfterSemi(retS->getLocEnd(), Pass.Ctx).isValid()) {
+ scope.IsFollowedBySimpleReturnStmt = true;
+ ++SI; // the return will be included in scope, don't check it.
+ }
+
+ for (; SI != SE; ++SI) {
+ nameUsedOutsideScope = !NameReferenceChecker(Pass.Ctx, scope,
+ referenceLoc,
+ declarationLoc).TraverseStmt(*SI);
+ if (nameUsedOutsideScope)
+ break;
+ }
+
+ // If not all references were cleared it means some variables/typenames/etc
+ // declared inside the pool scope are used outside of it.
+ // We won't try to rewrite the pool.
+ if (nameUsedOutsideScope) {
+ Pass.TA.reportError("a name is referenced outside the "
+ "NSAutoreleasePool scope that it was declared in", referenceLoc);
+ Pass.TA.reportNote("name declared here", declarationLoc);
+ Pass.TA.reportNote("intended @autoreleasepool scope begins here",
+ (*scope.Begin)->getLocStart());
+ Pass.TA.reportNote("intended @autoreleasepool scope ends here",
+ (*scope.End)->getLocStart());
+ return;
+ }
+ }
+
+ // Collect all releases of the pool; they will be removed.
+ {
+ ReleaseCollector releaseColl(scope.PoolVar, scope.Releases);
+ Stmt::child_iterator I = scope.Begin;
+ ++I;
+ for (; I != scope.End; ++I)
+ releaseColl.TraverseStmt(*I);
+ }
+
+ PoolVars[scope.PoolVar].Scopes.push_back(scope);
+ }
+
+ bool isPoolCreation(Expr *E) {
+ if (!E) return false;
+ E = getEssential(E);
+ ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E);
+ if (!ME) return false;
+ if (ME->getMethodFamily() == OMF_new &&
+ ME->getReceiverKind() == ObjCMessageExpr::Class &&
+ isNSAutoreleasePool(ME->getReceiverInterface()))
+ return true;
+ if (ME->getReceiverKind() == ObjCMessageExpr::Instance &&
+ ME->getMethodFamily() == OMF_init) {
+ Expr *rec = getEssential(ME->getInstanceReceiver());
+ if (ObjCMessageExpr *recME = dyn_cast_or_null<ObjCMessageExpr>(rec)) {
+ if (recME->getMethodFamily() == OMF_alloc &&
+ recME->getReceiverKind() == ObjCMessageExpr::Class &&
+ isNSAutoreleasePool(recME->getReceiverInterface()))
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ bool isPoolDrain(VarDecl *poolVar, Stmt *S) {
+ if (!S) return false;
+ S = getEssential(S);
+ ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S);
+ if (!ME) return false;
+ if (ME->getReceiverKind() == ObjCMessageExpr::Instance) {
+ Expr *rec = getEssential(ME->getInstanceReceiver());
+ if (DeclRefExpr *dref = dyn_cast<DeclRefExpr>(rec))
+ if (dref->getDecl() == poolVar)
+ return ME->getMethodFamily() == OMF_release ||
+ ME->getSelector() == DrainSel;
+ }
+
+ return false;
+ }
+
+ bool isNSAutoreleasePool(ObjCInterfaceDecl *IDecl) {
+ return IDecl && IDecl->getIdentifier() == PoolII;
+ }
+
+ bool isNSAutoreleasePool(QualType Ty) {
+ QualType pointee = Ty->getPointeeType();
+ if (pointee.isNull())
+ return false;
+ if (const ObjCInterfaceType *interT = pointee->getAs<ObjCInterfaceType>())
+ return isNSAutoreleasePool(interT->getDecl());
+ return false;
+ }
+
+ static Expr *getEssential(Expr *E) {
+ return cast<Expr>(getEssential((Stmt*)E));
+ }
+ static Stmt *getEssential(Stmt *S) {
+ if (ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(S))
+ S = EWC->getSubExpr();
+ if (Expr *E = dyn_cast<Expr>(S))
+ S = E->IgnoreParenCasts();
+ return S;
+ }
+
+ Stmt *Body;
+ MigrationPass &Pass;
+
+ IdentifierInfo *PoolII;
+ Selector DrainSel;
+
+ struct PoolVarInfo {
+ DeclStmt *Dcl;
+ ExprSet Refs;
+ SmallVector<PoolScope, 2> Scopes;
+
+ PoolVarInfo() : Dcl(0) { }
+ };
+
+ std::map<VarDecl *, PoolVarInfo> PoolVars;
+};
+
+} // anonymous namespace
+
+void trans::rewriteAutoreleasePool(MigrationPass &pass) {
+ BodyTransform<AutoreleasePoolRewriter> trans(pass);
+ trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
+}