TransProperties.cpp source code [clang_source_code/lib/ARCMigrate/TransProperties.cpp]

1	//===--- TransProperties.cpp - Transformations to ARC mode ----------------===//
2	//
3	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4	// See https://llvm.org/LICENSE.txt for license information.
5	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6	//
7	//===----------------------------------------------------------------------===//
8	//
9	// rewriteProperties:
10	//
11	// - Adds strong/weak/unsafe_unretained ownership specifier to properties that
12	// are missing one.
13	// - Migrates properties from (retain) to (strong) and (assign) to
14	// (unsafe_unretained/weak).
15	// - If a property is synthesized, adds the ownership specifier in the ivar
16	// backing the property.
17	//
18	// @interface Foo : NSObject {
19	// NSObject *x;
20	// }
21	// @property (assign) id x;
22	// @end
23	// ---->
24	// @interface Foo : NSObject {
25	// NSObject *__weak x;
26	// }
27	// @property (weak) id x;
28	// @end
29	//
30	//===----------------------------------------------------------------------===//
31
32	#include "Transforms.h"
33	#include "Internals.h"
34	#include "clang/Basic/SourceManager.h"
35	#include "clang/Lex/Lexer.h"
36	#include "clang/Sema/SemaDiagnostic.h"
37	#include <map>
38
39	using namespace clang;
40	using namespace arcmt;
41	using namespace trans;
42
43	namespace {
44
45	class PropertiesRewriter {
46	MigrationContext &MigrateCtx;
47	MigrationPass &Pass;
48	ObjCImplementationDecl *CurImplD;
49
50	enum PropActionKind {
51	PropAction_None,
52	PropAction_RetainReplacedWithStrong,
53	PropAction_AssignRemoved,
54	PropAction_AssignRewritten,
55	PropAction_MaybeAddWeakOrUnsafe
56	};
57
58	struct PropData {
59	ObjCPropertyDecl *PropD;
60	ObjCIvarDecl *IvarD;
61	ObjCPropertyImplDecl *ImplD;
62
63	PropData(ObjCPropertyDecl *propD)
64	: PropD(propD), IvarD(nullptr), ImplD(nullptr) {}
65	};
66
67	typedef SmallVector<PropData, 2> PropsTy;
68	typedef std::map<unsigned, PropsTy> AtPropDeclsTy;
69	AtPropDeclsTy AtProps;
70	llvm::DenseMap<IdentifierInfo *, PropActionKind> ActionOnProp;
71
72	public:
73	explicit PropertiesRewriter(MigrationContext &MigrateCtx)
74	: MigrateCtx(MigrateCtx), Pass(MigrateCtx.Pass) { }
75
76	static void collectProperties(ObjCContainerDecl *D, AtPropDeclsTy &AtProps,
77	AtPropDeclsTy *PrevAtProps = nullptr) {
78	for (auto *Prop : D->instance_properties()) {
79	if (Prop->getAtLoc().isInvalid())
80	continue;
81	unsigned RawLoc = Prop->getAtLoc().getRawEncoding();
82	if (PrevAtProps)
83	if (PrevAtProps->find(RawLoc) != PrevAtProps->end())
84	continue;
85	PropsTy &props = AtProps[RawLoc];
86	props.push_back(Prop);
87	}
88	}
89
90	void doTransform(ObjCImplementationDecl *D) {
91	CurImplD = D;
92	ObjCInterfaceDecl *iface = D->getClassInterface();
93	if (!iface)
94	return;
95
96	collectProperties(iface, AtProps);
97
98	// Look through extensions.
99	for (auto *Ext : iface->visible_extensions())
100	collectProperties(Ext, AtProps);
101
102	typedef DeclContext::specific_decl_iterator<ObjCPropertyImplDecl>
103	prop_impl_iterator;
104	for (prop_impl_iterator
105	I = prop_impl_iterator(D->decls_begin()),
106	E = prop_impl_iterator(D->decls_end()); I != E; ++I) {
107	ObjCPropertyImplDecl implD = I;
108	if (implD->getPropertyImplementation() != ObjCPropertyImplDecl::Synthesize)
109	continue;
110	ObjCPropertyDecl *propD = implD->getPropertyDecl();
111	if (!propD \|\| propD->isInvalidDecl())
112	continue;
113	ObjCIvarDecl *ivarD = implD->getPropertyIvarDecl();
114	if (!ivarD \|\| ivarD->isInvalidDecl())
115	continue;
116	unsigned rawAtLoc = propD->getAtLoc().getRawEncoding();
117	AtPropDeclsTy::iterator findAtLoc = AtProps.find(rawAtLoc);
118	if (findAtLoc == AtProps.end())
119	continue;
120
121	PropsTy &props = findAtLoc->second;
122	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I) {
123	if (I->PropD == propD) {
124	I->IvarD = ivarD;
125	I->ImplD = implD;
126	break;
127	}
128	}
129	}
130
131	for (AtPropDeclsTy::iterator
132	I = AtProps.begin(), E = AtProps.end(); I != E; ++I) {
133	SourceLocation atLoc = SourceLocation::getFromRawEncoding(I->first);
134	PropsTy &props = I->second;
135	if (!getPropertyType(props)->isObjCRetainableType())
136	continue;
137	if (hasIvarWithExplicitARCOwnership(props))
138	continue;
139
140	Transaction Trans(Pass.TA);
141	rewriteProperty(props, atLoc);
142	}
143	}
144
145	private:
146	void doPropAction(PropActionKind kind,
147	PropsTy &props, SourceLocation atLoc,
148	bool markAction = true) {
149	if (markAction)
150	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I)
151	ActionOnProp[I->PropD->getIdentifier()] = kind;
152
153	switch (kind) {
154	case PropAction_None:
155	return;
156	case PropAction_RetainReplacedWithStrong: {
157	StringRef toAttr = "strong";
158	MigrateCtx.rewritePropertyAttribute("retain", toAttr, atLoc);
159	return;
160	}
161	case PropAction_AssignRemoved:
162	return removeAssignForDefaultStrong(props, atLoc);
163	case PropAction_AssignRewritten:
164	return rewriteAssign(props, atLoc);
165	case PropAction_MaybeAddWeakOrUnsafe:
166	return maybeAddWeakOrUnsafeUnretainedAttr(props, atLoc);
167	}
168	}
169
170	void rewriteProperty(PropsTy &props, SourceLocation atLoc) {
171	ObjCPropertyDecl::PropertyAttributeKind propAttrs = getPropertyAttrs(props);
172
173	if (propAttrs & (ObjCPropertyDecl::OBJC_PR_copy \|
174	ObjCPropertyDecl::OBJC_PR_unsafe_unretained \|
175	ObjCPropertyDecl::OBJC_PR_strong \|
176	ObjCPropertyDecl::OBJC_PR_weak))
177	return;
178
179	if (propAttrs & ObjCPropertyDecl::OBJC_PR_retain) {
180	// strong is the default.
181	return doPropAction(PropAction_RetainReplacedWithStrong, props, atLoc);
182	}
183
184	bool HasIvarAssignedAPlusOneObject = hasIvarAssignedAPlusOneObject(props);
185
186	if (propAttrs & ObjCPropertyDecl::OBJC_PR_assign) {
187	if (HasIvarAssignedAPlusOneObject)
188	return doPropAction(PropAction_AssignRemoved, props, atLoc);
189	return doPropAction(PropAction_AssignRewritten, props, atLoc);
190	}
191
192	if (HasIvarAssignedAPlusOneObject \|\|
193	(Pass.isGCMigration() && !hasGCWeak(props, atLoc)))
194	return; // 'strong' by default.
195
196	return doPropAction(PropAction_MaybeAddWeakOrUnsafe, props, atLoc);
197	}
198
199	void removeAssignForDefaultStrong(PropsTy &props,
200	SourceLocation atLoc) const {
201	removeAttribute("retain", atLoc);
202	if (!removeAttribute("assign", atLoc))
203	return;
204
205	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I) {
206	if (I->ImplD)
207	Pass.TA.clearDiagnostic(diag::err_arc_strong_property_ownership,
208	diag::err_arc_assign_property_ownership,
209	diag::err_arc_inconsistent_property_ownership,
210	I->IvarD->getLocation());
211	}
212	}
213
214	void rewriteAssign(PropsTy &props, SourceLocation atLoc) const {
215	bool canUseWeak = canApplyWeak(Pass.Ctx, getPropertyType(props),
216	/AllowOnUnknownClass=/Pass.isGCMigration());
217	const char *toWhich =
218	(Pass.isGCMigration() && !hasGCWeak(props, atLoc)) ? "strong" :
219	(canUseWeak ? "weak" : "unsafe_unretained");
220
221	bool rewroteAttr = rewriteAttribute("assign", toWhich, atLoc);
222	if (!rewroteAttr)
223	canUseWeak = false;
224
225	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I) {
226	if (isUserDeclared(I->IvarD)) {
227	if (I->IvarD &&
228	I->IvarD->getType().getObjCLifetime() != Qualifiers::OCL_Weak) {
229	const char *toWhich =
230	(Pass.isGCMigration() && !hasGCWeak(props, atLoc)) ? "__strong " :
231	(canUseWeak ? "__weak " : "__unsafe_unretained ");
232	Pass.TA.insert(I->IvarD->getLocation(), toWhich);
233	}
234	}
235	if (I->ImplD)
236	Pass.TA.clearDiagnostic(diag::err_arc_strong_property_ownership,
237	diag::err_arc_assign_property_ownership,
238	diag::err_arc_inconsistent_property_ownership,
239	I->IvarD->getLocation());
240	}
241	}
242
243	void maybeAddWeakOrUnsafeUnretainedAttr(PropsTy &props,
244	SourceLocation atLoc) const {
245	bool canUseWeak = canApplyWeak(Pass.Ctx, getPropertyType(props),
246	/AllowOnUnknownClass=/Pass.isGCMigration());
247
248	bool addedAttr = addAttribute(canUseWeak ? "weak" : "unsafe_unretained",
249	atLoc);
250	if (!addedAttr)
251	canUseWeak = false;
252
253	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I) {
254	if (isUserDeclared(I->IvarD)) {
255	if (I->IvarD &&
256	I->IvarD->getType().getObjCLifetime() != Qualifiers::OCL_Weak)
257	Pass.TA.insert(I->IvarD->getLocation(),
258	canUseWeak ? "__weak " : "__unsafe_unretained ");
259	}
260	if (I->ImplD) {
261	Pass.TA.clearDiagnostic(diag::err_arc_strong_property_ownership,
262	diag::err_arc_assign_property_ownership,
263	diag::err_arc_inconsistent_property_ownership,
264	I->IvarD->getLocation());
265	Pass.TA.clearDiagnostic(
266	diag::err_arc_objc_property_default_assign_on_object,
267	I->ImplD->getLocation());
268	}
269	}
270	}
271
272	bool removeAttribute(StringRef fromAttr, SourceLocation atLoc) const {
273	return MigrateCtx.removePropertyAttribute(fromAttr, atLoc);
274	}
275
276	bool rewriteAttribute(StringRef fromAttr, StringRef toAttr,
277	SourceLocation atLoc) const {
278	return MigrateCtx.rewritePropertyAttribute(fromAttr, toAttr, atLoc);
279	}
280
281	bool addAttribute(StringRef attr, SourceLocation atLoc) const {
282	return MigrateCtx.addPropertyAttribute(attr, atLoc);
283	}
284
285	class PlusOneAssign : public RecursiveASTVisitor<PlusOneAssign> {
286	ObjCIvarDecl *Ivar;
287	public:
288	PlusOneAssign(ObjCIvarDecl *D) : Ivar(D) {}
289
290	bool VisitBinAssign(BinaryOperator *E) {
291	Expr *lhs = E->getLHS()->IgnoreParenImpCasts();
292	if (ObjCIvarRefExpr *RE = dyn_cast<ObjCIvarRefExpr>(lhs)) {
293	if (RE->getDecl() != Ivar)
294	return true;
295
296	if (isPlusOneAssign(E))
297	return false;
298	}
299
300	return true;
301	}
302	};
303
304	bool hasIvarAssignedAPlusOneObject(PropsTy &props) const {
305	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I) {
306	PlusOneAssign oneAssign(I->IvarD);
307	bool notFound = oneAssign.TraverseDecl(CurImplD);
308	if (!notFound)
309	return true;
310	}
311
312	return false;
313	}
314
315	bool hasIvarWithExplicitARCOwnership(PropsTy &props) const {
316	if (Pass.isGCMigration())
317	return false;
318
319	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I) {
320	if (isUserDeclared(I->IvarD)) {
321	if (isa<AttributedType>(I->IvarD->getType()))
322	return true;
323	if (I->IvarD->getType().getLocalQualifiers().getObjCLifetime()
324	!= Qualifiers::OCL_Strong)
325	return true;
326	}
327	}
328
329	return false;
330	}
331
332	// Returns true if all declarations in the @property have GC __weak.
333	bool hasGCWeak(PropsTy &props, SourceLocation atLoc) const {
334	if (!Pass.isGCMigration())
335	return false;
336	if (props.empty())
337	return false;
338	return MigrateCtx.AtPropsWeak.count(atLoc.getRawEncoding());
339	}
340
341	bool isUserDeclared(ObjCIvarDecl *ivarD) const {
342	return ivarD && !ivarD->getSynthesize();
343	}
344
345	QualType getPropertyType(PropsTy &props) const {
346	assert(!props.empty());
347	QualType ty = props[0].PropD->getType().getUnqualifiedType();
348
349	#ifndef NDEBUG
350	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I)
351	PropD->getType().getUnqualifiedType()", "/home/seafit/code_projects/clang_source/clang/lib/ARCMigrate/TransProperties.cpp", 351, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(ty == I->PropD->getType().getUnqualifiedType());
352	#endif
353
354	return ty;
355	}
356
357	ObjCPropertyDecl::PropertyAttributeKind
358	getPropertyAttrs(PropsTy &props) const {
359	assert(!props.empty());
360	ObjCPropertyDecl::PropertyAttributeKind
361	attrs = props[0].PropD->getPropertyAttributesAsWritten();
362
363	#ifndef NDEBUG
364	for (PropsTy::iterator I = props.begin(), E = props.end(); I != E; ++I)
365	PropD->getPropertyAttributesAsWritten()", "/home/seafit/code_projects/clang_source/clang/lib/ARCMigrate/TransProperties.cpp", 365, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(attrs == I->PropD->getPropertyAttributesAsWritten());
366	#endif
367
368	return attrs;
369	}
370	};
371
372	} // anonymous namespace
373
374	void PropertyRewriteTraverser::traverseObjCImplementation(
375	ObjCImplementationContext &ImplCtx) {
376	PropertiesRewriter(ImplCtx.getMigrationContext())
377	.doTransform(ImplCtx.getImplementationDecl());
378	}
379

clang::arcmt::trans::PropertyRewriteTraverser::traverseObjCImplementation

Clang Project