objc runtime 756.2 & implement objc_opt_class for passing compile.

README.md

@@ -1,2 +1,2 @@
 # objc-runtime
-objc runtime 750
+objc runtime 756.2

debug-objc/main.m

@@ -10,7 +10,7 @@
 int main(int argc, const char * argv[]) {
     @autoreleasepool {
         // insert code here...
-        NSLog(@"Hello, World!");
+        NSLog(@"Hello, World! %@", [NSString class]);
     }
     return 0;
 }

include/System/pthread_machdep.h

@@ -71,14 +71,14 @@
 #define _PTHREAD_TSD_SLOT_DYLD_1		1
 #define _PTHREAD_TSD_SLOT_DYLD_2		2
 #define _PTHREAD_TSD_SLOT_DYLD_3		3
-#define _PTHREAD_TSD_RESERVED_SLOT_COUNT	4
+//#define _PTHREAD_TSD_RESERVED_SLOT_COUNT	4
 /* To mirror the usage by dyld for Unwind_SjLj */
 #define _PTHREAD_TSD_SLOT_DYLD_8		8
 
 /* Keys 10 - 29 are for Libc/Libsystem internal ussage */
 /* used as __pthread_tsd_first + Num  */
 #define __PTK_LIBC_LOCALE_KEY		10
-#define __PTK_LIBC_TTYNAME_KEY		11
+//#define __PTK_LIBC_TTYNAME_KEY		11
 #define __PTK_LIBC_LOCALTIME_KEY	12
 #define __PTK_LIBC_GMTIME_KEY		13
 #define __PTK_LIBC_GDTOA_BIGINT_KEY	14
@@ -297,8 +297,8 @@ extern "C" {
 
 #endif
 
-#define LOCK_INIT(l)	((l) = 0)
-#define LOCK_INITIALIZER 0
+//#define LOCK_INIT(l)	((l) = 0)
+//#define LOCK_INITIALIZER 0
 
 #endif /* ! __ASSEMBLER__ */
 #endif /* _POSIX_PTHREAD_MACHDEP_H */

runtime/Messengers.subproj/objc-msg-arm64.s

@@ -189,16 +189,19 @@ LExit$0:
 #define GETIMP 1
 #define LOOKUP 2
 
-// CacheHit: x17 = cached IMP, x12 = address of cached IMP
+// CacheHit: x17 = cached IMP, x12 = address of cached IMP, x1 = SEL
 .macro CacheHit
 .if $0 == NORMAL
-	TailCallCachedImp x17, x12	// authenticate and call imp
+	TailCallCachedImp x17, x12, x1	// authenticate and call imp
 .elseif $0 == GETIMP
 	mov	p0, p17
-	AuthAndResignAsIMP x0, x12	// authenticate imp and re-sign as IMP
-	ret				// return IMP
+	cbz	p0, 9f			// don't ptrauth a nil imp
+	AuthAndResignAsIMP x0, x12, x1	// authenticate imp and re-sign as IMP
+9:	ret				// return IMP
 .elseif $0 == LOOKUP
-	AuthAndResignAsIMP x17, x12	// authenticate imp and re-sign as IMP
+	// No nil check for ptrauth: the caller would crash anyway when they
+	// jump to a nil IMP. We don't care if that jump also fails ptrauth.
+	AuthAndResignAsIMP x17, x12, x1	// authenticate imp and re-sign as IMP
 	ret				// return imp via x17
 .else
 .abort oops

runtime/NSObject.mm

@@ -308,7 +308,7 @@ BOOL objc_should_deallocate(id object) {
             !((objc_class *)cls)->isInitialized()) 
         {
             SideTable::unlockTwo<haveOld, haveNew>(oldTable, newTable);
-            _class_initialize(_class_getNonMetaClass(cls, (id)newObj));
+            class_initialize(cls, (id)newObj);
 
             // If this class is finished with +initialize then we're good.
             // If this class is still running +initialize on this thread 
@@ -506,7 +506,7 @@ BOOL objc_should_deallocate(id object) {
         }
         else {
             table->unlock();
-            _class_initialize(cls);
+            class_initialize(cls, obj);
             goto retry;
         }
     }
@@ -614,7 +614,12 @@ BOOL objc_should_deallocate(id object) {
     }
 
     ~magic_t() {
-        m[0] = m[1] = m[2] = m[3] = 0;
+        // Clear magic before deallocation.
+        // This prevents some false positives in memory debugging tools.
+        // fixme semantically this should be memset_s(), but the
+        // compiler doesn't optimize that at all (rdar://44856676).
+        volatile uint64_t *p = (volatile uint64_t *)m;
+        p[0] = 0; p[1] = 0;
     }
 
     bool check() const {
@@ -1782,6 +1787,12 @@ void objc_overrelease_during_dealloc_error(void)
     return callAlloc(cls, true/*checkNil*/, true/*allocWithZone*/);
 }
 
+// Calls [[cls alloc] init].
+id
+objc_alloc_init(Class cls)
+{
+    return [callAlloc(cls, true/*checkNil*/, false/*allocWithZone*/) init];
+}
 
 void
 _objc_rootDealloc(id obj)

runtime/arm64-asm.h

@@ -108,7 +108,8 @@
 .endmacro
 
 .macro TailCallCachedImp
-	// $0 = cached imp, $1 = address of cached imp
+	// $0 = cached imp, $1 = address of cached imp, $2 = SEL
+	eor	$1, $1, $2	// mix SEL into ptrauth modifier
 	brab	$0, $1
 .endmacro
 
@@ -123,8 +124,11 @@
 .endmacro
 
 .macro AuthAndResignAsIMP
-	// $0 = cached imp, $1 = address of cached imp
+	// $0 = cached imp, $1 = address of cached imp, $2 = SEL
+	// note: assumes the imp is not nil
+	eor	$1, $1, $2	// mix SEL into ptrauth modifier
 	autib	$0, $1		// authenticate cached imp
+	ldr	xzr, [$0]	// crash if authentication failed
 	paciza	$0		// resign cached imp as IMP
 .endmacro
 
@@ -138,7 +142,7 @@
 .endmacro
 
 .macro TailCallCachedImp
-	// $0 = cached imp, $1 = address of cached imp
+	// $0 = cached imp, $1 = address of cached imp, $2 = SEL
 	br	$0
 .endmacro
 
@@ -153,6 +157,7 @@
 .endmacro
 
 .macro AuthAndResignAsIMP
+	// $0 = cached imp, $1 = address of cached imp, $2 = SEL
 	// empty
 .endmacro	
 

runtime/message.h

@@ -198,9 +198,12 @@ objc_msgSend_fp2ret(void /* id self, SEL op, ... */ )
  *  you must use \c objc_msgSend_fpret for functions returning non-integral type. For \c float or 
  *  \c long \c double return types, cast the function to an appropriate function pointer type first.
  */
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wincompatible-library-redeclaration"
 OBJC_EXPORT double
 objc_msgSend_fpret(id _Nullable self, SEL _Nonnull op, ...)
     OBJC_AVAILABLE(10.4, 2.0, 9.0, 1.0, 2.0);
+#pragma clang diagnostic pop
 
 /* Use objc_msgSendSuper() for fp-returning messages to super. */
 /* See also objc_msgSendv_fpret() below. */

runtime/objc-abi.h

@@ -100,24 +100,36 @@ typedef struct objc_image_info {
 #if __cplusplus >= 201103L
   private:
     enum : uint32_t {
+        // 1 byte assorted flags
         IsReplacement       = 1<<0,  // used for Fix&Continue, now ignored
         SupportsGC          = 1<<1,  // image supports GC
         RequiresGC          = 1<<2,  // image requires GC
         OptimizedByDyld     = 1<<3,  // image is from an optimized shared cache
         CorrectedSynthesize = 1<<4,  // used for an old workaround, now ignored
         IsSimulated         = 1<<5,  // image compiled for a simulator platform
         HasCategoryClassProperties  = 1<<6,  // class properties in category_t
+        // not yet used = 1<<7
 
-        SwiftVersionMaskShift = 8,
-        SwiftVersionMask    = 0xff << SwiftVersionMaskShift  // Swift ABI version
+        // 1 byte Swift unstable ABI version number
+        SwiftUnstableVersionMaskShift = 8,
+        SwiftUnstableVersionMask = 0xff << SwiftUnstableVersionMaskShift,
 
+        // 2 byte Swift stable ABI version number
+        SwiftStableVersionMaskShift = 16,
+        SwiftStableVersionMask = 0xffffUL << SwiftStableVersionMaskShift
     };
-   public:
+  public:
     enum : uint32_t {
+        // Values for SwiftUnstableVersion
+        // All stable ABIs store SwiftVersion5 here.
         SwiftVersion1   = 1,
         SwiftVersion1_2 = 2,
         SwiftVersion2   = 3,
-        SwiftVersion3   = 4
+        SwiftVersion3   = 4,
+        SwiftVersion4   = 5,
+        SwiftVersion4_1 = 6,
+        SwiftVersion4_2 = 6,  // [sic]
+        SwiftVersion5   = 7
     };
 
   public:
@@ -126,8 +138,8 @@ typedef struct objc_image_info {
     bool requiresGC()      const { return flags & RequiresGC; }
     bool optimizedByDyld() const { return flags & OptimizedByDyld; }
     bool hasCategoryClassProperties() const { return flags & HasCategoryClassProperties; }
-    bool containsSwift()   const { return (flags & SwiftVersionMask) != 0; }
-    uint32_t swiftVersion() const { return (flags & SwiftVersionMask) >> SwiftVersionMaskShift; }
+    bool containsSwift()   const { return (flags & SwiftUnstableVersionMask) != 0; }
+    uint32_t swiftUnstableVersion() const { return (flags & SwiftUnstableVersionMask) >> SwiftUnstableVersionMaskShift; }
 #endif
 } objc_image_info;
 

runtime/objc-block-trampolines.h

@@ -37,6 +37,13 @@
  * objc-block-trampolines.h: Symbols for IMP block trampolines
  */
 
+// WARNING: remapped code and dtrace do not play well together. Dtrace
+// will place trap instructions to instrument the code, which then get
+// remapped along with everything else. The remapped traps are not
+// recognized by dtrace and the process crashes. To avoid this, dtrace
+// blacklists this library by name. Do not change the name of this
+// library. rdar://problem/42627391
+
 #include <objc/objc-api.h>
 
 OBJC_EXPORT const char _objc_blockTrampolineImpl

runtime/objc-block-trampolines.mm

@@ -163,7 +163,8 @@ void Initialize() {
         void *dylib = dlopen("/usr/lib/libobjc-trampolines.dylib",
                              RTLD_NOW | RTLD_LOCAL | RTLD_FIRST);
         if (!dylib) {
-            _objc_fatal("couldn't dlopen libobjc-trampolines.dylib");
+            _objc_fatal("couldn't dlopen libobjc-trampolines.dylib: %s",
+                        dlerror());
         }
 
         auto t = new TrampolinePointers(dylib);
@@ -177,13 +178,18 @@ void Initialize() {
     uintptr_t textSegment() { return get()->textSegment; }
     uintptr_t textSegmentSize() { return get()->textSegmentSize; }
 
+    // See comments below about PAGE_SIZE and PAGE_MAX_SIZE.
+    uintptr_t dataSize() { return PAGE_MAX_SIZE; }
+
     uintptr_t impl() { return get()->impl.address(); }
     uintptr_t start() { return get()->start.address(); }
 };
 
 static TrampolinePointerWrapper Trampolines;
 
 // argument mode identifier
+// Some calculations assume that these modes are sequential starting from 0.
+// This order must match the order of the trampoline's assembly code.
 typedef enum {
     ReturnValueInRegisterArgumentMode,
 #if SUPPORT_STRET
@@ -211,8 +217,17 @@ void Initialize() {
 {
     TrampolineBlockPageGroup *nextPageGroup; // linked list of all pages
     TrampolineBlockPageGroup *nextAvailablePage; // linked list of pages with available slots
-    
+
     uintptr_t nextAvailable; // index of next available slot, endIndex() if no more available
+
+    const void * TrampolinePtrauth const text;  // text VM region; stored only for the benefit of the leaks tool
+
+    TrampolineBlockPageGroup()
+        : nextPageGroup(nil)
+        , nextAvailablePage(nil)
+        , nextAvailable(startIndex())
+        , text((const void *)((uintptr_t)this + Trampolines.dataSize()))
+    { }
 
     // Payload data: block pointers and free list.
     // Bytes parallel with trampoline header code are the fields above or unused
@@ -249,7 +264,7 @@ static uintptr_t startIndex() {
     }
 
     static uintptr_t endIndex() {
-        return (uintptr_t)PAGE_MAX_SIZE / slotSize();
+        return (uintptr_t)Trampolines.dataSize() / slotSize();
     }
 
     static bool validIndex(uintptr_t index) {
@@ -262,8 +277,10 @@ static bool validIndex(uintptr_t index) {
     }
 
     uintptr_t trampolinesForMode(int aMode) {
-        // Skip over data page and Mach-O page.
-        return (uintptr_t)this + PAGE_MAX_SIZE * (2 + aMode);
+        // Skip over the data area, one page of Mach-O headers,
+        // and one text page for each mode before this one.
+        return (uintptr_t)this + Trampolines.dataSize() +
+            PAGE_MAX_SIZE * (1 + aMode);
     }
 
     IMP trampoline(int aMode, uintptr_t index) {
@@ -334,7 +351,7 @@ static void check() {
 
     auto textSource = Trampolines.textSegment();
     auto textSourceSize = Trampolines.textSegmentSize();
-    auto dataSize = PAGE_MAX_SIZE;
+    auto dataSize = Trampolines.dataSize();
 
     // Allocate a single contiguous region big enough to hold data+text.
     kern_return_t result;
@@ -358,10 +375,7 @@ static void check() {
         _objc_fatal("vm_remap trampolines failed (%d)", result);
     }
 
-    TrampolineBlockPageGroup *pageGroup = (TrampolineBlockPageGroup *) dataAddress;
-    pageGroup->nextAvailable = pageGroup->startIndex();
-    pageGroup->nextPageGroup = nil;
-    pageGroup->nextAvailablePage = nil;
+    auto *pageGroup = new ((void*)dataAddress) TrampolineBlockPageGroup;
 
     if (HeadPageGroup) {
         TrampolineBlockPageGroup *lastPageGroup = HeadPageGroup;