Fix the NSIndexSet formatter for macOS Sonoma

[jingham]

Summary

Just mutatis mutandis for the Foundation changes. The current NSIndexSet test fails on Sonoma w/o this patch and exercise the different forms, so no new tests are required.

[mib]

lldb/source/Plugins/Language/ObjC/Cocoa.cpp

294

Do we want to overwrite the count read previously ?

[bulbazord]

lldb/source/Plugins/Language/ObjC/Cocoa.cpp

278

I'm pretty sure __builtin_popcount and friends are GNU extensions not supported by MSVC. You'll probably need to abstract this out with C preprocessor macro guards.

Alternatively, I think llvm has its own popcount implementation with llvm::popcount in include/llvm/ADT/bit.h.

[jingham]

Use llvm::popcount instead of using the builtin directly.

[jingham]

lldb/source/Plugins/Language/ObjC/Cocoa.cpp

278

Good catch. The llvm one is just a wrapper for the builtin when available and a by-hand version otherwise, so might as well use that one.

294

This code was originally written by Sean, who loved to write any code with complex logic in the form:

do {

/// Complex Logic here

} while (0);

so that he could exit the whole construct with a "break". After we get the bit mask value from the tagged pointer we break which sends us immediately to line 343. So that setting and this one are on non-intersecting code paths.

[bulbazord]

It would be nice if we could clean up what mode is. There's a lot of bit-wise operations and setting it to 1 and 2 and it's not clear what each one might mean in each case... Some kind of enum or semantic meaning for each number would be nice. Either way, I think I'm on board with the logic in general. Just one question though.

lldb/source/Plugins/Language/ObjC/Cocoa.cpp

303

This clobbers the previously set count on line 294. What of that count?

[jingham]

Remove redundant code

[jingham]

lldb/source/Plugins/Language/ObjC/Cocoa.cpp

303

Oh, that's me saying it was bad to use a variable called count when it should be bitfield, adding the new one and then forgetting to delete the count version.

lldb/source/Plugins/Language/ObjC/Cocoa.cpp

 }
 
 bool lldb_private::formatters::NSIndexSetSummaryProvider(
     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
   ProcessSP process_sp = valobj.GetProcessSP();
   if (!process_sp)
     return false;
 
-  ObjCLanguageRuntime *runtime = ObjCLanguageRuntime::Get(*process_sp);
+  AppleObjCRuntime *runtime = llvm::dyn_cast_or_null<AppleObjCRuntime>(
+      ObjCLanguageRuntime::Get(*process_sp));
 
   if (!runtime)
     return false;
 
   ObjCLanguageRuntime::ClassDescriptorSP descriptor(
       runtime->GetClassDescriptor(valobj));
 
   if (!descriptor || !descriptor->IsValid())
bool lldb_private::formatters::NSIndexSetSummaryProvider(
 
   if (class_name.empty())
     return false;
 
   uint64_t count = 0;
 
   do {
     if (class_name == "NSIndexSet" || class_name == "NSMutableIndexSet") {
+      // Foundation version 2000 added a bitmask if the index set fit in 64 bits
+      // and a Tagged Pointer version if the bitmask is small enough to fit in
+      // the tagged pointer payload.  
+      // It also changed the layout (but not the size) of the set descriptor.
+
+      // First check whether this is a tagged pointer.  The bitmask will be in
+      // the payload of the tagged pointer.
+      uint64_t payload;
+      if (runtime->GetFoundationVersion() >= 2000  
+          && descriptor->GetTaggedPointerInfo(nullptr, nullptr, &payload)) {
+        count = llvm::popcount(payload);
+        break;
+      }
+      // The first 32 bits describe the index set in all cases:
       Status error;
       uint32_t mode = process_sp->ReadUnsignedIntegerFromMemory(
             valobj_addr + ptr_size, 4, 0, error);
       if (error.Fail())
         return false;
+      // Now check if the index is held in a bitmask in the object:
+      if (runtime->GetFoundationVersion() >= 2000) {
+        // The first two bits are "isSingleRange" and "isBitfield".  If this is
+        // a bitfield we handle it here, otherwise set mode appropriately and
+        // the rest of the treatment is in common.
+        if ((mode & 2) == 2) {
+          // The bitfield is a 64 bit uint at the beginning of the data var.
+          uint64_t bitfield = process_sp->ReadUnsignedIntegerFromMemory(
+            valobj_addr + 2 * ptr_size, 8, 0, error);
+          if (error.Fail())
+            return false;
+          count = llvm::popcount(bitfield);
+          break;
+        }
+        // It wasn't a bitfield, so read the isSingleRange from its new loc:
+        if ((mode & 1) == 1)
+          mode = 1; // this means the set only has one range
+        else
+          mode = 2; // this means the set has multiple ranges
+      } else {
         // this means the set is empty - count = 0
         if ((mode & 1) == 1) {
           count = 0;
           break;
         }
+      
         if ((mode & 2) == 2)
           mode = 1; // this means the set only has one range
         else
           mode = 2; // this means the set has multiple ranges
+      }
       if (mode == 1) {
         count = process_sp->ReadUnsignedIntegerFromMemory(
             valobj_addr + 3 * ptr_size, ptr_size, 0, error);
         if (error.Fail())
           return false;
       } else {
         // read a pointer to the data at 2*ptr_size
         count = process_sp->ReadUnsignedIntegerFromMemory(