mirror of
https://github.com/capstone-engine/llvm-capstone.git
synced 2024-12-07 05:59:42 +00:00
8ae1203992
llvm-svn: 208163
470 lines
16 KiB
C++
470 lines
16 KiB
C++
//===--- TransUnbridgedCasts.cpp - Transformations to ARC mode ------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// rewriteUnbridgedCasts:
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//
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// A cast of non-objc pointer to an objc one is checked. If the non-objc pointer
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// is from a file-level variable, __bridge cast is used to convert it.
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// For the result of a function call that we know is +1/+0,
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// __bridge/CFBridgingRelease is used.
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//
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// NSString *str = (NSString *)kUTTypePlainText;
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// str = b ? kUTTypeRTF : kUTTypePlainText;
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// NSString *_uuidString = (NSString *)CFUUIDCreateString(kCFAllocatorDefault,
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// _uuid);
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// ---->
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// NSString *str = (__bridge NSString *)kUTTypePlainText;
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// str = (__bridge NSString *)(b ? kUTTypeRTF : kUTTypePlainText);
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// NSString *_uuidString = (NSString *)
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// CFBridgingRelease(CFUUIDCreateString(kCFAllocatorDefault, _uuid));
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//
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// For a C pointer to ObjC, for casting 'self', __bridge is used.
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//
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// CFStringRef str = (CFStringRef)self;
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// ---->
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// CFStringRef str = (__bridge CFStringRef)self;
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//
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// Uses of Block_copy/Block_release macros are rewritten:
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//
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// c = Block_copy(b);
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// Block_release(c);
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// ---->
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// c = [b copy];
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// <removed>
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//
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//===----------------------------------------------------------------------===//
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#include "Transforms.h"
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#include "Internals.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/Attr.h"
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#include "clang/AST/ParentMap.h"
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#include "clang/Analysis/DomainSpecific/CocoaConventions.h"
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#include "clang/Basic/SourceManager.h"
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#include "clang/Lex/Lexer.h"
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#include "clang/Sema/SemaDiagnostic.h"
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#include "llvm/ADT/SmallString.h"
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using namespace clang;
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using namespace arcmt;
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using namespace trans;
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namespace {
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class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
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MigrationPass &Pass;
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IdentifierInfo *SelfII;
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std::unique_ptr<ParentMap> StmtMap;
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Decl *ParentD;
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Stmt *Body;
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mutable std::unique_ptr<ExprSet> Removables;
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public:
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UnbridgedCastRewriter(MigrationPass &pass)
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: Pass(pass), ParentD(nullptr), Body(nullptr) {
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SelfII = &Pass.Ctx.Idents.get("self");
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}
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void transformBody(Stmt *body, Decl *ParentD) {
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this->ParentD = ParentD;
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Body = body;
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StmtMap.reset(new ParentMap(body));
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TraverseStmt(body);
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}
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bool TraverseBlockDecl(BlockDecl *D) {
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// ParentMap does not enter into a BlockDecl to record its stmts, so use a
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// new UnbridgedCastRewriter to handle the block.
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UnbridgedCastRewriter(Pass).transformBody(D->getBody(), D);
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return true;
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}
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bool VisitCastExpr(CastExpr *E) {
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if (E->getCastKind() != CK_CPointerToObjCPointerCast &&
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E->getCastKind() != CK_BitCast &&
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E->getCastKind() != CK_AnyPointerToBlockPointerCast)
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return true;
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QualType castType = E->getType();
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Expr *castExpr = E->getSubExpr();
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QualType castExprType = castExpr->getType();
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if (castType->isObjCRetainableType() == castExprType->isObjCRetainableType())
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return true;
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bool exprRetainable = castExprType->isObjCIndirectLifetimeType();
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bool castRetainable = castType->isObjCIndirectLifetimeType();
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if (exprRetainable == castRetainable) return true;
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if (castExpr->isNullPointerConstant(Pass.Ctx,
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Expr::NPC_ValueDependentIsNull))
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return true;
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SourceLocation loc = castExpr->getExprLoc();
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if (loc.isValid() && Pass.Ctx.getSourceManager().isInSystemHeader(loc))
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return true;
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if (castType->isObjCRetainableType())
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transformNonObjCToObjCCast(E);
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else
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transformObjCToNonObjCCast(E);
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return true;
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}
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private:
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void transformNonObjCToObjCCast(CastExpr *E) {
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if (!E) return;
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// Global vars are assumed that are cast as unretained.
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if (isGlobalVar(E))
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if (E->getSubExpr()->getType()->isPointerType()) {
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castToObjCObject(E, /*retained=*/false);
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return;
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}
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// If the cast is directly over the result of a Core Foundation function
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// try to figure out whether it should be cast as retained or unretained.
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Expr *inner = E->IgnoreParenCasts();
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if (CallExpr *callE = dyn_cast<CallExpr>(inner)) {
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if (FunctionDecl *FD = callE->getDirectCallee()) {
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if (FD->hasAttr<CFReturnsRetainedAttr>()) {
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castToObjCObject(E, /*retained=*/true);
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return;
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}
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if (FD->hasAttr<CFReturnsNotRetainedAttr>()) {
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castToObjCObject(E, /*retained=*/false);
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return;
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}
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if (FD->isGlobal() &&
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FD->getIdentifier() &&
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ento::cocoa::isRefType(E->getSubExpr()->getType(), "CF",
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FD->getIdentifier()->getName())) {
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StringRef fname = FD->getIdentifier()->getName();
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if (fname.endswith("Retain") ||
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fname.find("Create") != StringRef::npos ||
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fname.find("Copy") != StringRef::npos) {
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// Do not migrate to couple of bridge transfer casts which
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// cancel each other out. Leave it unchanged so error gets user
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// attention instead.
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if (FD->getName() == "CFRetain" &&
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FD->getNumParams() == 1 &&
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FD->getParent()->isTranslationUnit() &&
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FD->isExternallyVisible()) {
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Expr *Arg = callE->getArg(0);
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if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
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const Expr *sub = ICE->getSubExpr();
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QualType T = sub->getType();
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if (T->isObjCObjectPointerType())
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return;
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}
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}
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castToObjCObject(E, /*retained=*/true);
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return;
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}
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if (fname.find("Get") != StringRef::npos) {
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castToObjCObject(E, /*retained=*/false);
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return;
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}
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}
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}
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}
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// If returning an ivar or a member of an ivar from a +0 method, use
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// a __bridge cast.
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Expr *base = inner->IgnoreParenImpCasts();
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while (isa<MemberExpr>(base))
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base = cast<MemberExpr>(base)->getBase()->IgnoreParenImpCasts();
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if (isa<ObjCIvarRefExpr>(base) &&
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isa<ReturnStmt>(StmtMap->getParentIgnoreParenCasts(E))) {
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if (ObjCMethodDecl *method = dyn_cast_or_null<ObjCMethodDecl>(ParentD)) {
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if (!method->hasAttr<NSReturnsRetainedAttr>()) {
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castToObjCObject(E, /*retained=*/false);
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return;
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}
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}
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}
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}
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void castToObjCObject(CastExpr *E, bool retained) {
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rewriteToBridgedCast(E, retained ? OBC_BridgeTransfer : OBC_Bridge);
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}
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void rewriteToBridgedCast(CastExpr *E, ObjCBridgeCastKind Kind) {
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Transaction Trans(Pass.TA);
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rewriteToBridgedCast(E, Kind, Trans);
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}
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void rewriteToBridgedCast(CastExpr *E, ObjCBridgeCastKind Kind,
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Transaction &Trans) {
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TransformActions &TA = Pass.TA;
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// We will remove the compiler diagnostic.
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if (!TA.hasDiagnostic(diag::err_arc_mismatched_cast,
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diag::err_arc_cast_requires_bridge,
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E->getLocStart())) {
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Trans.abort();
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return;
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}
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StringRef bridge;
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switch(Kind) {
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case OBC_Bridge:
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bridge = "__bridge "; break;
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case OBC_BridgeTransfer:
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bridge = "__bridge_transfer "; break;
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case OBC_BridgeRetained:
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bridge = "__bridge_retained "; break;
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}
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TA.clearDiagnostic(diag::err_arc_mismatched_cast,
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diag::err_arc_cast_requires_bridge,
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E->getLocStart());
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if (Kind == OBC_Bridge || !Pass.CFBridgingFunctionsDefined()) {
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if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(E)) {
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TA.insertAfterToken(CCE->getLParenLoc(), bridge);
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} else {
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SourceLocation insertLoc = E->getSubExpr()->getLocStart();
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SmallString<128> newCast;
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newCast += '(';
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newCast += bridge;
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newCast += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
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newCast += ')';
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if (isa<ParenExpr>(E->getSubExpr())) {
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TA.insert(insertLoc, newCast.str());
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} else {
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newCast += '(';
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TA.insert(insertLoc, newCast.str());
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TA.insertAfterToken(E->getLocEnd(), ")");
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}
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}
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} else {
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assert(Kind == OBC_BridgeTransfer || Kind == OBC_BridgeRetained);
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SmallString<32> BridgeCall;
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Expr *WrapE = E->getSubExpr();
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SourceLocation InsertLoc = WrapE->getLocStart();
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SourceManager &SM = Pass.Ctx.getSourceManager();
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char PrevChar = *SM.getCharacterData(InsertLoc.getLocWithOffset(-1));
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if (Lexer::isIdentifierBodyChar(PrevChar, Pass.Ctx.getLangOpts()))
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BridgeCall += ' ';
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if (Kind == OBC_BridgeTransfer)
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BridgeCall += "CFBridgingRelease";
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else
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BridgeCall += "CFBridgingRetain";
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if (isa<ParenExpr>(WrapE)) {
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TA.insert(InsertLoc, BridgeCall);
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} else {
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BridgeCall += '(';
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TA.insert(InsertLoc, BridgeCall);
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TA.insertAfterToken(WrapE->getLocEnd(), ")");
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}
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}
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}
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void rewriteCastForCFRetain(CastExpr *castE, CallExpr *callE) {
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Transaction Trans(Pass.TA);
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Pass.TA.replace(callE->getSourceRange(), callE->getArg(0)->getSourceRange());
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rewriteToBridgedCast(castE, OBC_BridgeRetained, Trans);
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}
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void getBlockMacroRanges(CastExpr *E, SourceRange &Outer, SourceRange &Inner) {
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SourceManager &SM = Pass.Ctx.getSourceManager();
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SourceLocation Loc = E->getExprLoc();
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assert(Loc.isMacroID());
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SourceLocation MacroBegin, MacroEnd;
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std::tie(MacroBegin, MacroEnd) = SM.getImmediateExpansionRange(Loc);
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SourceRange SubRange = E->getSubExpr()->IgnoreParenImpCasts()->getSourceRange();
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SourceLocation InnerBegin = SM.getImmediateMacroCallerLoc(SubRange.getBegin());
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SourceLocation InnerEnd = SM.getImmediateMacroCallerLoc(SubRange.getEnd());
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Outer = SourceRange(MacroBegin, MacroEnd);
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Inner = SourceRange(InnerBegin, InnerEnd);
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}
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void rewriteBlockCopyMacro(CastExpr *E) {
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SourceRange OuterRange, InnerRange;
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getBlockMacroRanges(E, OuterRange, InnerRange);
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Transaction Trans(Pass.TA);
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Pass.TA.replace(OuterRange, InnerRange);
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Pass.TA.insert(InnerRange.getBegin(), "[");
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Pass.TA.insertAfterToken(InnerRange.getEnd(), " copy]");
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Pass.TA.clearDiagnostic(diag::err_arc_mismatched_cast,
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diag::err_arc_cast_requires_bridge,
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OuterRange);
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}
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void removeBlockReleaseMacro(CastExpr *E) {
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SourceRange OuterRange, InnerRange;
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getBlockMacroRanges(E, OuterRange, InnerRange);
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Transaction Trans(Pass.TA);
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Pass.TA.clearDiagnostic(diag::err_arc_mismatched_cast,
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diag::err_arc_cast_requires_bridge,
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OuterRange);
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if (!hasSideEffects(E, Pass.Ctx)) {
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if (tryRemoving(cast<Expr>(StmtMap->getParentIgnoreParenCasts(E))))
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return;
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}
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Pass.TA.replace(OuterRange, InnerRange);
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}
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bool tryRemoving(Expr *E) const {
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if (!Removables) {
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Removables.reset(new ExprSet);
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collectRemovables(Body, *Removables);
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}
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if (Removables->count(E)) {
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Pass.TA.removeStmt(E);
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return true;
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}
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return false;
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}
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void transformObjCToNonObjCCast(CastExpr *E) {
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SourceLocation CastLoc = E->getExprLoc();
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if (CastLoc.isMacroID()) {
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StringRef MacroName = Lexer::getImmediateMacroName(CastLoc,
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Pass.Ctx.getSourceManager(),
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Pass.Ctx.getLangOpts());
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if (MacroName == "Block_copy") {
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rewriteBlockCopyMacro(E);
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return;
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}
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if (MacroName == "Block_release") {
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removeBlockReleaseMacro(E);
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return;
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}
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}
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if (isSelf(E->getSubExpr()))
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return rewriteToBridgedCast(E, OBC_Bridge);
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CallExpr *callE;
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if (isPassedToCFRetain(E, callE))
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return rewriteCastForCFRetain(E, callE);
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ObjCMethodFamily family = getFamilyOfMessage(E->getSubExpr());
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if (family == OMF_retain)
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return rewriteToBridgedCast(E, OBC_BridgeRetained);
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if (family == OMF_autorelease || family == OMF_release) {
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std::string err = "it is not safe to cast to '";
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err += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
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err += "' the result of '";
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err += family == OMF_autorelease ? "autorelease" : "release";
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err += "' message; a __bridge cast may result in a pointer to a "
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"destroyed object and a __bridge_retained may leak the object";
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Pass.TA.reportError(err, E->getLocStart(),
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E->getSubExpr()->getSourceRange());
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Stmt *parent = E;
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do {
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parent = StmtMap->getParentIgnoreParenImpCasts(parent);
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} while (parent && isa<ExprWithCleanups>(parent));
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if (ReturnStmt *retS = dyn_cast_or_null<ReturnStmt>(parent)) {
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std::string note = "remove the cast and change return type of function "
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"to '";
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note += E->getSubExpr()->getType().getAsString(Pass.Ctx.getPrintingPolicy());
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note += "' to have the object automatically autoreleased";
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Pass.TA.reportNote(note, retS->getLocStart());
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}
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}
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Expr *subExpr = E->getSubExpr();
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// Look through pseudo-object expressions.
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if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(subExpr)) {
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subExpr = pseudo->getResultExpr();
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assert(subExpr && "no result for pseudo-object of non-void type?");
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}
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if (ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(subExpr)) {
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if (implCE->getCastKind() == CK_ARCConsumeObject)
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return rewriteToBridgedCast(E, OBC_BridgeRetained);
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if (implCE->getCastKind() == CK_ARCReclaimReturnedObject)
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return rewriteToBridgedCast(E, OBC_Bridge);
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}
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bool isConsumed = false;
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if (isPassedToCParamWithKnownOwnership(E, isConsumed))
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return rewriteToBridgedCast(E, isConsumed ? OBC_BridgeRetained
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: OBC_Bridge);
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}
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static ObjCMethodFamily getFamilyOfMessage(Expr *E) {
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E = E->IgnoreParenCasts();
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if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E))
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return ME->getMethodFamily();
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return OMF_None;
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}
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bool isPassedToCFRetain(Expr *E, CallExpr *&callE) const {
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if ((callE = dyn_cast_or_null<CallExpr>(
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StmtMap->getParentIgnoreParenImpCasts(E))))
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if (FunctionDecl *
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FD = dyn_cast_or_null<FunctionDecl>(callE->getCalleeDecl()))
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if (FD->getName() == "CFRetain" && FD->getNumParams() == 1 &&
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FD->getParent()->isTranslationUnit() &&
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FD->isExternallyVisible())
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return true;
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return false;
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}
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bool isPassedToCParamWithKnownOwnership(Expr *E, bool &isConsumed) const {
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if (CallExpr *callE = dyn_cast_or_null<CallExpr>(
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StmtMap->getParentIgnoreParenImpCasts(E)))
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if (FunctionDecl *
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FD = dyn_cast_or_null<FunctionDecl>(callE->getCalleeDecl())) {
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unsigned i = 0;
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for (unsigned e = callE->getNumArgs(); i != e; ++i) {
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Expr *arg = callE->getArg(i);
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if (arg == E || arg->IgnoreParenImpCasts() == E)
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break;
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}
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if (i < callE->getNumArgs() && i < FD->getNumParams()) {
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ParmVarDecl *PD = FD->getParamDecl(i);
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if (PD->hasAttr<CFConsumedAttr>()) {
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isConsumed = true;
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return true;
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}
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}
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}
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return false;
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}
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bool isSelf(Expr *E) const {
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E = E->IgnoreParenLValueCasts();
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if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
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if (ImplicitParamDecl *IPD = dyn_cast<ImplicitParamDecl>(DRE->getDecl()))
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if (IPD->getIdentifier() == SelfII)
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return true;
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return false;
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}
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};
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} // end anonymous namespace
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void trans::rewriteUnbridgedCasts(MigrationPass &pass) {
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BodyTransform<UnbridgedCastRewriter> trans(pass);
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trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
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}
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