Fix the case where the number of selectors grows to more than 2^16 and we need

to fall back to 3-level dtables.  

Added a test case that registers far more selectors than a sane program
contains and tries to use them.

Test/CMakeLists.txt

@@ -11,6 +11,7 @@ set(TESTS
 	ExceptionTest.m
 	ForeignException.m
 	Forward.m
+	ManyManySelectors.m
 	NestedExceptions.m
 	PropertyAttributeTest.m
 	PropertyIntrospectionTest.m

Test/ManyManySelectors.m

@@ -0,0 +1,35 @@
+#include "Test.h"
+#include <inttypes.h>
+#include <stdio.h>
+#include <string.h>
+
+static BOOL methodCalled = NO;
+
+static id x(id self, SEL _cmd)
+{
+	methodCalled = YES;
+	assert(strcmp("selectoreffff", sel_getName(_cmd)) == 0);
+	return self;
+}
+
+int main(void)
+{
+	char selBuffer[] = "selectorXXXXXXXX";
+	SEL nextSel;
+	Class cls = [Test class];
+	assert(cls != Nil);
+	for (uint32_t i=0 ; i<0xf0000 ; i++)
+	{
+		snprintf(selBuffer, 16, "selector%" PRIx32, i);
+		nextSel = sel_registerName(selBuffer);
+	}
+	assert(class_addMethod(object_getClass([Test class]), nextSel, (IMP)x, "@@:"));
+	assert(cls == [Test class]);
+	// Test both the C and assembly code paths.
+	objc_msg_lookup(cls, nextSel)(cls, nextSel);
+	assert(methodCalled == YES);
+	methodCalled = NO;
+	objc_msgSend([Test class], nextSel);
+	assert(methodCalled == YES);
+	return 0;
+}

dtable.c

@@ -18,7 +18,8 @@ PRIVATE dtable_t uninstalled_dtable;
 PRIVATE InitializingDtable *temporary_dtables;
 /** Lock used to protect the temporary dtables list. */
 PRIVATE mutex_t initialize_lock;
-/** The size of the largest dtable, rounded up to the nearest power of two. */
+/** The size of the largest dtable.  This is a sparse array shift value, so is
+ * 2^x in increments of 8. */
 static uint32_t dtable_depth = 8;
 
 struct objc_slot* objc_get_slot(Class cls, SEL selector);
@@ -555,11 +556,13 @@ PRIVATE void objc_resize_dtables(uint32_t newSize)
 
 	LOCK_RUNTIME_FOR_SCOPE();
 
-	dtable_depth <<= 1;
+	if (1<<dtable_depth > newSize) { return; }
+
+	dtable_depth += 8;
 
 	uint32_t oldMask = uninstalled_dtable->mask;
 
-	SparseArrayExpandingArray(uninstalled_dtable);
+	SparseArrayExpandingArray(uninstalled_dtable, dtable_depth);
 	// Resize all existing dtables
 	void *e = NULL;
 	struct objc_class *next;
@@ -569,7 +572,8 @@ PRIVATE void objc_resize_dtables(uint32_t newSize)
 			NULL != next->dtable &&
 			((SparseArray*)next->dtable)->mask == oldMask)
 		{
-			SparseArrayExpandingArray((void*)next->dtable);
+			SparseArrayExpandingArray((void*)next->dtable, dtable_depth);
+			SparseArrayExpandingArray((void*)next->isa->dtable, dtable_depth);
 		}
 	}
 }

objc/runtime.h

@@ -208,56 +208,7 @@ typedef struct
 #endif
 
 #include "slot.h"
-
-#if defined(__x86_64) || defined(__i386) || defined(__arm__) || \
-	defined(__mips_n64) || defined(__mips_n32)
-/**
- * Standard message sending function.  This function must be cast to the
- * correct types for the function before use.  The first argument is the
- * receiver and the second the selector.
- *
- * Note that this function is not available on all architectures.  For a more
- * portable solution to sending arbitrary messages, consider using
- * objc_msg_lookup_sender() and then calling the returned IMP directly.
- *
- * This version of the function is used for all messages that return either an
- * integer, a pointer, or a small structure value that is returned in
- * registers.  Be aware that calling conventions differ between operating
- * systems even within the same architecture, so take great care if using this
- * function for small (two integer) structures.
- */
-id objc_msgSend(id self, SEL _cmd, ...);
-/**
- * Standard message sending function.  This function must be cast to the
- * correct types for the function before use.  The first argument is the
- * receiver and the second the selector.
- *
- * Note that this function is not available on all architectures.  For a more
- * portable solution to sending arbitrary messages, consider using
- * objc_msg_lookup_sender() and then calling the returned IMP directly.
- *
- * This version of the function is used for all messages that return a
- * structure that is not returned in registers.  Be aware that calling
- * conventions differ between operating systems even within the same
- * architecture, so take great care if using this function for small (two
- * integer) structures.
- */
-void objc_msgSend_stret(id self, SEL _cmd, ...);
-/**
- * Standard message sending function.  This function must be cast to the
- * correct types for the function before use.  The first argument is the
- * receiver and the second the selector.
- *
- * Note that this function is not available on all architectures.  For a more
- * portable solution to sending arbitrary messages, consider using
- * objc_msg_lookup_sender() and then calling the returned IMP directly.
- *
- * This version of the function is used for all messages that return floating
- * point values.
- */
-long double objc_msgSend_fpret(id self, SEL _cmd, ...);
-
-#endif
+#include "message.h"
 
 
 /**

sarray2.c

@@ -8,6 +8,12 @@
 
 static void *EmptyArrayData[256];
 static SparseArray EmptyArray = { 0xff, 0, 0, (void**)&EmptyArrayData};
+static void *EmptyArrayData8[256] = { [0 ... 255] = &EmptyArray };
+static SparseArray EmptyArray8 = { 0xff00, 8, 0, (void**)&EmptyArrayData8};
+static void *EmptyArrayData16[256] = { [0 ... 255] = &EmptyArray8 };
+static SparseArray EmptyArray16 = { 0xff0000, 16, 0, (void**)&EmptyArrayData16};
+static void *EmptyArrayData24[256] = { [0 ... 255] = &EmptyArray16 };
+static SparseArray EmptyArray24 = { 0xff0000, 24, 0, (void**)&EmptyArrayData24};
 
 #define MAX_INDEX(sarray) (sarray->mask >> sarray->shift)
 #define DATA_SIZE(sarray) ((sarray->mask >> sarray->shift) + 1)
@@ -17,17 +23,35 @@ static SparseArray EmptyArray = { 0xff, 0, 0, (void**)&EmptyArrayData};
 #define base_shift 8
 #define base_mask ((1<<base_shift) - 1)
 
+void *EmptyChildForShift(uint32_t shift)
+{
+	switch(shift)
+	{
+		default: UNREACHABLE("Broken sparse array");
+		case 8:
+			return &EmptyArray;
+		case 16:
+			return &EmptyArray8;
+		case 24:
+			return &EmptyArray16;
+		case 32:
+			return &EmptyArray24;
+	}
+}
+
 static void init_pointers(SparseArray * sarray)
 {
 	sarray->data = calloc(DATA_SIZE(sarray), sizeof(void*));
 	if(sarray->shift != 0)
 	{
+		void *data = EmptyChildForShift(sarray->shift);
 		for(unsigned i=0 ; i<=MAX_INDEX(sarray) ; i++)
 		{
-			sarray->data[i] = &EmptyArray;
+			sarray->data[i] = data;
 		}
 	}
 }
+
 PRIVATE SparseArray * SparseArrayNewWithDepth(uint32_t depth)
 {
 	SparseArray * sarray = calloc(1, sizeof(SparseArray));
@@ -42,8 +66,13 @@ PRIVATE SparseArray *SparseArrayNew()
 {
 	return SparseArrayNewWithDepth(32);
 }
-PRIVATE SparseArray *SparseArrayExpandingArray(SparseArray *sarray)
+PRIVATE SparseArray *SparseArrayExpandingArray(SparseArray *sarray, uint32_t new_depth)
 {
+	if (new_depth == sarray->shift)
+	{
+		return sarray;
+	}
+	assert(new_depth > sarray->shift);
 	// Expanding a child sarray has undefined results.
 	assert(sarray->refCount == 1);
 	SparseArray *new = calloc(1, sizeof(SparseArray));
@@ -51,12 +80,12 @@ PRIVATE SparseArray *SparseArrayExpandingArray(SparseArray *sarray)
 	new->shift = sarray->shift;
 	new->mask = sarray->mask;
 	void **newData = malloc(DATA_SIZE(sarray) * sizeof(void*));
-	for(unsigned i=0 ; i<=MAX_INDEX(sarray) ; i++)
+	void *data = EmptyChildForShift(new->shift + 8);
+	for(unsigned i=1 ; i<=MAX_INDEX(sarray) ; i++)
 	{
-		newData[i] = &EmptyArray;
+		newData[i] = data;
 	}
 	new->data = sarray->data;
-	// new is now an exact copy of sarray.
 	newData[0] = new;
 	sarray->data = newData;
 	// Now, any lookup in sarray for any value less than its capacity will have
@@ -65,7 +94,7 @@ PRIVATE SparseArray *SparseArrayExpandingArray(SparseArray *sarray)
 	sarray->shift += base_shift;
 	// Finally, set the mask to the correct value.  Now all lookups should work.
 	sarray->mask <<= base_shift;
-	return new;
+	return sarray;
 }
 
 static void *SparseArrayFind(SparseArray * sarray, uint32_t * index)
@@ -86,27 +115,34 @@ static void *SparseArrayFind(SparseArray * sarray, uint32_t * index)
 	}
 	else while (j<max)
 	{
+		// If the shift is not 0, then we need to recursively look at child
+		// nodes.
 		uint32_t zeromask = ~(sarray->mask >> base_shift);
 		while (j<max)
 		{
 			//Look in child nodes
-			if (sarray->data[j] != SARRAY_EMPTY)
-			{
-				void * ret = SparseArrayFind(sarray->data[j], index);
-				if (ret != SARRAY_EMPTY)
-				{
-					return ret;
-				}
-				// The recursive call will set index to the correct value for
-				// the next index, but won't update j
-			}
-			else
+			SparseArray *child = sarray->data[j];
+			// Skip over known-empty children
+			if ((&EmptyArray == child) ||
+			    (&EmptyArray8 == child) ||
+			    (&EmptyArray16 == child) ||
+			    (&EmptyArray24 == child))
 			{
 				//Add 2^n to index so j is still correct
 				(*index) += 1<<sarray->shift;
 				//Zero off the next component of the index so we don't miss any.
 				*index &= zeromask;
 			}
+			else
+			{
+				// The recursive call will set index to the correct value for
+				// the next index, but won't update j
+				void * ret = SparseArrayFind(child, index);
+				if (ret != SARRAY_EMPTY)
+				{
+					return ret;
+				}
+			}
 			//Go to the next child
 			j++;
 		}
@@ -126,7 +162,10 @@ PRIVATE void SparseArrayInsert(SparseArray * sarray, uint32_t index, void *value
 	{
 		uint32_t i = MASK_INDEX(index);
 		SparseArray *child = sarray->data[i];
-		if(&EmptyArray == child)
+		if ((&EmptyArray == child) ||
+		    (&EmptyArray8 == child) ||
+		    (&EmptyArray16 == child) ||
+		    (&EmptyArray24 == child))
 		{
 			// Insert missing nodes
 			SparseArray * newsarray = calloc(1, sizeof(SparseArray));
@@ -185,6 +224,8 @@ PRIVATE void SparseArrayDestroy(SparseArray * sarray)
 {
 	// Don't really delete this sarray if its ref count is > 0
 	if (sarray == &EmptyArray || 
+	    sarray == &EmptyArray8 || 
+	    sarray == &EmptyArray16 || 
 		(__sync_sub_and_fetch(&sarray->refCount, 1) > 0))
  	{
 		return;

sarray2.h

@@ -112,7 +112,7 @@ SparseArray *SparseArrayNewWithDepth(uint32_t depth);
  * Returns a new sparse array created by adding this one as the first child
  * node in an expanded one.
  */
-SparseArray *SparseArrayExpandingArray(SparseArray *sarray);
+SparseArray *SparseArrayExpandingArray(SparseArray *sarray, uint32_t new_depth);
 /**
  * Insert a value at the specified index.
  */