src/hotspot/share/oops/compressedKlass.inline.hpp

@@ -30,34 +30,31 @@
  #include "memory/universe.hpp"
  #include "oops/oop.hpp"
  #include "utilities/align.hpp"
  #include "utilities/globalDefinitions.hpp"
  
- static inline bool check_alignment(Klass* v) {
-   return (intptr_t)v % KlassAlignmentInBytes == 0;
- }
- 
- inline Klass* CompressedKlassPointers::decode_not_null_without_asserts(narrowKlass v, address narrow_base, int shift) {
-   return (Klass*)((uintptr_t)narrow_base +((uintptr_t)v << shift));
+ inline Klass* CompressedKlassPointers::decode_not_null_without_asserts(narrowKlass v, address narrow_base_base, int shift) {
+   return (Klass*)((uintptr_t)narrow_base_base +((uintptr_t)v << shift));
  }
  
  inline Klass* CompressedKlassPointers::decode_not_null(narrowKlass v, address narrow_base, int shift) {
    assert(!is_null(v), "narrow klass value can never be zero");
    Klass* result = decode_not_null_without_asserts(v, narrow_base, shift);
-   assert(check_alignment(result), "address not aligned: " PTR_FORMAT, p2i(result));
+   DEBUG_ONLY(check_valid_klass(result, narrow_base, shift));
    return result;
  }
  
+ inline narrowKlass CompressedKlassPointers::encode_not_null_without_asserts(Klass* k, address narrow_base, int shift) {
+   return (narrowKlass)(pointer_delta(k, narrow_base, 1) >> shift);
+ }
+ 
  inline narrowKlass CompressedKlassPointers::encode_not_null(Klass* v, address narrow_base, int shift) {
    assert(!is_null(v), "klass value can never be zero");
-   assert(check_alignment(v), "Address not aligned");
-   uint64_t pd = (uint64_t)(pointer_delta(v, narrow_base, 1));
-   assert(KlassEncodingMetaspaceMax > pd, "change encoding max if new encoding");
-   uint64_t result = pd >> shift;
-   assert((result & CONST64(0xffffffff00000000)) == 0, "narrow klass pointer overflow");
+   DEBUG_ONLY(check_valid_klass(v);)
+   narrowKlass result = encode_not_null_without_asserts(v, narrow_base, shift);
    assert(decode_not_null((narrowKlass)result, narrow_base, shift) == v, "reversibility");
-   return (narrowKlass)result;
+   return result;
  }
  
  inline Klass* CompressedKlassPointers::decode_not_null_without_asserts(narrowKlass v) {
    return decode_not_null_without_asserts(v, base(), shift());
  }

@@ -65,21 +62,55 @@
  inline Klass* CompressedKlassPointers::decode_without_asserts(narrowKlass v) {
    return is_null(v) ? nullptr : decode_not_null_without_asserts(v);
  }
  
  inline Klass* CompressedKlassPointers::decode_not_null(narrowKlass v) {
+   DEBUG_ONLY(check_valid_narrow_klass_id(v);)
    return decode_not_null(v, base(), shift());
  }
  
  inline Klass* CompressedKlassPointers::decode(narrowKlass v) {
    return is_null(v) ? nullptr : decode_not_null(v);
  }
  
  inline narrowKlass CompressedKlassPointers::encode_not_null(Klass* v) {
-   return encode_not_null(v, base(), shift());
+   narrowKlass nk = encode_not_null(v, base(), shift());
+   DEBUG_ONLY(check_valid_narrow_klass_id(nk);)
+   return nk;
  }
  
  inline narrowKlass CompressedKlassPointers::encode(Klass* v) {
    return is_null(v) ? (narrowKlass)0 : encode_not_null(v);
  }
  
+ #ifdef ASSERT
+ inline void CompressedKlassPointers::check_valid_klass(const Klass* k, address base, int shift) {
+   const int log_alignment = MAX2(3, shift); // always at least 64-bit aligned
+   assert(is_aligned(k, nth_bit(log_alignment)), "Klass (" PTR_FORMAT ") not properly aligned to %zu",
+          p2i(k), nth_bit(shift));
+   const address encoding_end = base + nth_bit(narrow_klass_pointer_bits() + shift);
+   assert((address)k >= base && (address)k < encoding_end,
+          "Klass (" PTR_FORMAT ") falls outside of the valid encoding range [" PTR_FORMAT "-" PTR_FORMAT ")",
+          p2i(k), p2i(base), p2i(encoding_end));
+ }
+ 
+ inline void CompressedKlassPointers::check_valid_klass(const Klass* k) {
+   assert(UseCompressedClassPointers, "Only call for +UseCCP");
+   check_valid_klass(k, base(), shift());
+   // Also assert that k falls into what we know is the valid Klass range. This is usually smaller
+   // than the encoding range (e.g. encoding range covers 4G, but we only have 1G class space and a
+   // tiny bit of CDS => 1.1G)
+   const address klassrange_end = base() + range();
+   assert((address)k < klassrange_end,
+       "Klass (" PTR_FORMAT ") falls outside of the valid klass range [" PTR_FORMAT "-" PTR_FORMAT ")",
+       p2i(k), p2i(base()), p2i(klassrange_end));
+ }
+ inline void CompressedKlassPointers::check_valid_narrow_klass_id(narrowKlass nk) {
+   assert(UseCompressedClassPointers, "Only call for +UseCCP");
+   const uint64_t nk_mask = ~right_n_bits(narrow_klass_pointer_bits());
+   assert(((uint64_t)nk & nk_mask) == 0, "narrow klass id bit spillover (%u)", nk);
+   assert(nk >= _lowest_valid_narrow_klass_id &&
+          nk <= _highest_valid_narrow_klass_id, "narrowKlass ID out of range (%u)", nk);
+ }
+ #endif // ASSERT
+ 
  #endif // SHARE_OOPS_COMPRESSEDKLASS_INLINE_HPP