[lld-macho] Change personalities entry type to Ptr to avoid overflowing uint32

[oontvoo]

Summary

We push the CompactUnwindEntry::personality into this vector<uint32_t>.
On 64-bit, CompactUnwindEntry::personality is uint64 so it'd overflow and cause the find() to never find a matching entry, hence the "too many personalities ...." error message.

Bug: PR51262

[int3]

would be nice to have a test for this, but I guess it's somewhat awkward to write...

[oontvoo]

Thanks!

lld/MachO/UnwindInfoSection.cpp

public:
   void addInput(ConcatInputSection *) override;
   void finalize() override;
   void writeTo(uint8_t *buf) const override;
 
 private:
   std::vector<std::pair<compact_unwind_encoding_t, size_t>> commonEncodings;
   EncodingMap commonEncodingIndexes;
   // Indices of personality functions within the GOT.
-  std::vector<uint32_t> personalities;
+  std::vector<Ptr> personalities;
   SmallDenseMap<std::pair<InputSection *, uint64_t /* addend */>, Symbol *>
       personalityTable;
   std::vector<unwind_info_section_header_lsda_index_entry> lsdaEntries;
   // Map of function offset (from the image base) to an index within the LSDA
   // array.
   DenseMap<uint32_t, uint32_t> functionToLsdaIndex;
   std::vector<CompactUnwindEntry<Ptr>> cuVector;
   std::vector<CompactUnwindEntry<Ptr> *> cuPtrVector;
relocateCompactUnwind(ConcatOutputSection *compactUnwindSection,
   }
 }
 
 // There should only be a handful of unique personality pointers, so we can
 // encode them as 2-bit indices into a small array.
 template <class Ptr>
 static void
 encodePersonalities(const std::vector<CompactUnwindEntry<Ptr> *> &cuPtrVector,
-                    std::vector<uint32_t> &personalities) {
+                    std::vector<Ptr> &personalities) {
   for (CompactUnwindEntry<Ptr> *cu : cuPtrVector) {
     if (cu->personality == 0)
       continue;
     // Linear search is fast enough for a small array.
     auto it = find(personalities, cu->personality);
     uint32_t personalityIndex; // 1-based index
     if (it != personalities.end()) {
       personalityIndex = std::distance(personalities.begin(), it) + 1;