1 //===- ObjCRuntime.h - Objective-C Runtime Configuration --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// Defines types useful for describing an Objective-C runtime.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_BASIC_OBJCRUNTIME_H
16 #define LLVM_CLANG_BASIC_OBJCRUNTIME_H
18 #include "clang/Basic/LLVM.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/VersionTuple.h"
27 /// The basic abstraction for the target Objective-C runtime.
30 /// The basic Objective-C runtimes that we know about.
32 /// 'macosx' is the Apple-provided NeXT-derived runtime on Mac OS
33 /// X platforms that use the non-fragile ABI; the version is a
34 /// release of that OS.
37 /// 'macosx-fragile' is the Apple-provided NeXT-derived runtime on
38 /// Mac OS X platforms that use the fragile ABI; the version is a
39 /// release of that OS.
42 /// 'ios' is the Apple-provided NeXT-derived runtime on iOS or the iOS
43 /// simulator; it is always non-fragile. The version is a release
47 /// 'watchos' is a variant of iOS for Apple's watchOS. The version
48 /// is a release version of watchOS.
51 /// 'gcc' is the Objective-C runtime shipped with GCC, implementing a
52 /// fragile Objective-C ABI
55 /// 'gnustep' is the modern non-fragile GNUstep runtime.
58 /// 'objfw' is the Objective-C runtime included in ObjFW
63 Kind TheKind = MacOSX;
67 /// A bogus initialization of the runtime.
68 ObjCRuntime() = default;
69 ObjCRuntime(Kind kind, const VersionTuple &version)
70 : TheKind(kind), Version(version) {}
72 void set(Kind kind, VersionTuple version) {
77 Kind getKind() const { return TheKind; }
78 const VersionTuple &getVersion() const { return Version; }
80 /// Does this runtime follow the set of implied behaviors for a
81 /// "non-fragile" ABI?
82 bool isNonFragile() const {
84 case FragileMacOSX: return false;
85 case GCC: return false;
86 case MacOSX: return true;
87 case GNUstep: return true;
88 case ObjFW: return true;
89 case iOS: return true;
90 case WatchOS: return true;
92 llvm_unreachable("bad kind");
95 /// The inverse of isNonFragile(): does this runtime follow the set of
96 /// implied behaviors for a "fragile" ABI?
97 bool isFragile() const { return !isNonFragile(); }
99 /// The default dispatch mechanism to use for the specified architecture
100 bool isLegacyDispatchDefaultForArch(llvm::Triple::ArchType Arch) {
101 // The GNUstep runtime uses a newer dispatch method by default from
102 // version 1.6 onwards
103 if (getKind() == GNUstep && getVersion() >= VersionTuple(1, 6)) {
104 if (Arch == llvm::Triple::arm ||
105 Arch == llvm::Triple::x86 ||
106 Arch == llvm::Triple::x86_64)
109 else if ((getKind() == MacOSX) && isNonFragile() &&
110 (getVersion() >= VersionTuple(10, 0)) &&
111 (getVersion() < VersionTuple(10, 6)))
112 return Arch != llvm::Triple::x86_64;
113 // Except for deployment target of 10.5 or less,
114 // Mac runtimes use legacy dispatch everywhere now.
118 /// Is this runtime basically of the GNU family of runtimes?
119 bool isGNUFamily() const {
131 llvm_unreachable("bad kind");
134 /// Is this runtime basically of the NeXT family of runtimes?
135 bool isNeXTFamily() const {
136 // For now, this is just the inverse of isGNUFamily(), but that's
137 // not inherently true.
138 return !isGNUFamily();
141 /// Does this runtime allow ARC at all?
142 bool allowsARC() const {
145 // No stub library for the fragile runtime.
146 return getVersion() >= VersionTuple(10, 7);
147 case MacOSX: return true;
148 case iOS: return true;
149 case WatchOS: return true;
150 case GCC: return false;
151 case GNUstep: return true;
152 case ObjFW: return true;
154 llvm_unreachable("bad kind");
157 /// Does this runtime natively provide the ARC entrypoints?
159 /// ARC cannot be directly supported on a platform that does not provide
160 /// these entrypoints, although it may be supportable via a stub
162 bool hasNativeARC() const {
164 case FragileMacOSX: return getVersion() >= VersionTuple(10, 7);
165 case MacOSX: return getVersion() >= VersionTuple(10, 7);
166 case iOS: return getVersion() >= VersionTuple(5);
167 case WatchOS: return true;
169 case GCC: return false;
170 case GNUstep: return getVersion() >= VersionTuple(1, 6);
171 case ObjFW: return true;
173 llvm_unreachable("bad kind");
176 /// Does this runtime provide ARC entrypoints that are likely to be faster
177 /// than an ordinary message send of the appropriate selector?
179 /// The ARC entrypoints are guaranteed to be equivalent to just sending the
180 /// corresponding message. If the entrypoint is implemented naively as just a
181 /// message send, using it is a trade-off: it sacrifices a few cycles of
182 /// overhead to save a small amount of code. However, it's possible for
183 /// runtimes to detect and special-case classes that use "standard"
184 /// retain/release behavior; if that's dynamically a large proportion of all
185 /// retained objects, using the entrypoint will also be faster than using a
188 /// When this method returns true, Clang will turn non-super message sends of
189 /// certain selectors into calls to the correspond entrypoint:
190 /// retain => objc_retain
191 /// release => objc_release
192 /// autorelease => objc_autorelease
193 bool shouldUseARCFunctionsForRetainRelease() const {
198 return getVersion() >= VersionTuple(10, 10);
200 return getVersion() >= VersionTuple(8);
210 llvm_unreachable("bad kind");
213 /// Does this runtime provide entrypoints that are likely to be faster
214 /// than an ordinary message send of the "alloc" selector?
216 /// The "alloc" entrypoint is guaranteed to be equivalent to just sending the
217 /// corresponding message. If the entrypoint is implemented naively as just a
218 /// message send, using it is a trade-off: it sacrifices a few cycles of
219 /// overhead to save a small amount of code. However, it's possible for
220 /// runtimes to detect and special-case classes that use "standard"
221 /// alloc behavior; if that's dynamically a large proportion of all
222 /// objects, using the entrypoint will also be faster than using a message
225 /// When this method returns true, Clang will turn non-super message sends of
226 /// certain selectors into calls to the corresponding entrypoint:
227 /// alloc => objc_alloc
228 /// allocWithZone:nil => objc_allocWithZone
229 bool shouldUseRuntimeFunctionsForAlloc() const {
234 return getVersion() >= VersionTuple(10, 10);
236 return getVersion() >= VersionTuple(8);
247 llvm_unreachable("bad kind");
250 /// Does this runtime supports optimized setter entrypoints?
251 bool hasOptimizedSetter() const {
254 return getVersion() >= VersionTuple(10, 8);
256 return (getVersion() >= VersionTuple(6));
260 return getVersion() >= VersionTuple(1, 7);
266 /// Does this runtime allow the use of __weak?
267 bool allowsWeak() const {
268 return hasNativeWeak();
271 /// Does this runtime natively provide ARC-compliant 'weak'
273 bool hasNativeWeak() const {
274 // Right now, this is always equivalent to whether the runtime
275 // natively supports ARC decision.
276 return hasNativeARC();
279 /// Does this runtime directly support the subscripting methods?
281 /// This is really a property of the library, not the runtime.
282 bool hasSubscripting() const {
284 case FragileMacOSX: return false;
285 case MacOSX: return getVersion() >= VersionTuple(10, 11);
286 case iOS: return getVersion() >= VersionTuple(9);
287 case WatchOS: return true;
289 // This is really a lie, because some implementations and versions
290 // of the runtime do not support ARC. Probably -fgnu-runtime
291 // should imply a "maximal" runtime or something?
292 case GCC: return true;
293 case GNUstep: return true;
294 case ObjFW: return true;
296 llvm_unreachable("bad kind");
299 /// Does this runtime allow sizeof or alignof on object types?
300 bool allowsSizeofAlignof() const {
304 /// Does this runtime allow pointer arithmetic on objects?
306 /// This covers +, -, ++, --, and (if isSubscriptPointerArithmetic()
308 bool allowsPointerArithmetic() const {
320 llvm_unreachable("bad kind");
323 /// Is subscripting pointer arithmetic?
324 bool isSubscriptPointerArithmetic() const {
325 return allowsPointerArithmetic();
328 /// Does this runtime provide an objc_terminate function?
330 /// This is used in handlers for exceptions during the unwind process;
331 /// without it, abort() must be used in pure ObjC files.
332 bool hasTerminate() const {
334 case FragileMacOSX: return getVersion() >= VersionTuple(10, 8);
335 case MacOSX: return getVersion() >= VersionTuple(10, 8);
336 case iOS: return getVersion() >= VersionTuple(5);
337 case WatchOS: return true;
338 case GCC: return false;
339 case GNUstep: return false;
340 case ObjFW: return false;
342 llvm_unreachable("bad kind");
345 /// Does this runtime support weakly importing classes?
346 bool hasWeakClassImport() const {
348 case MacOSX: return true;
349 case iOS: return true;
350 case WatchOS: return true;
351 case FragileMacOSX: return false;
352 case GCC: return true;
353 case GNUstep: return true;
354 case ObjFW: return true;
356 llvm_unreachable("bad kind");
359 /// Does this runtime use zero-cost exceptions?
360 bool hasUnwindExceptions() const {
362 case MacOSX: return true;
363 case iOS: return true;
364 case WatchOS: return true;
365 case FragileMacOSX: return false;
366 case GCC: return true;
367 case GNUstep: return true;
368 case ObjFW: return true;
370 llvm_unreachable("bad kind");
373 bool hasAtomicCopyHelper() const {
381 return getVersion() >= VersionTuple(1, 7);
382 default: return false;
386 /// Is objc_unsafeClaimAutoreleasedReturnValue available?
387 bool hasARCUnsafeClaimAutoreleasedReturnValue() const {
391 return getVersion() >= VersionTuple(10, 11);
393 return getVersion() >= VersionTuple(9);
395 return getVersion() >= VersionTuple(2);
403 /// Are the empty collection symbols available?
404 bool hasEmptyCollections() const {
409 return getVersion() >= VersionTuple(10, 11);
411 return getVersion() >= VersionTuple(9);
413 return getVersion() >= VersionTuple(2);
417 /// Try to parse an Objective-C runtime specification from the given
420 /// \return true on error.
421 bool tryParse(StringRef input);
423 std::string getAsString() const;
425 friend bool operator==(const ObjCRuntime &left, const ObjCRuntime &right) {
426 return left.getKind() == right.getKind() &&
427 left.getVersion() == right.getVersion();
430 friend bool operator!=(const ObjCRuntime &left, const ObjCRuntime &right) {
431 return !(left == right);
435 raw_ostream &operator<<(raw_ostream &out, const ObjCRuntime &value);
439 #endif // LLVM_CLANG_BASIC_OBJCRUNTIME_H