src/share/vm/oops/arrayOop.cpp

rev 2779 : 7102044: G1: VM crashes with assert(old_end != new_end) failed: don't call this otherwise
Summary: arrayOopDesc::max_array_length() should return a value that does not overflow a size_t if it is converted to bytes.
Reviewed-by: duke

*** 22,31 ****
   *
   */
  
  #include "precompiled.hpp"
  #include "oops/arrayOop.hpp"
- #include "oops/objArrayOop.hpp"
- #include "oops/oop.inline.hpp"
- #include "oops/symbol.hpp"
  
! // <<this page is intentionally left blank>>
--- 22,88 ----
   *
   */
  
  #include "precompiled.hpp"
  #include "oops/arrayOop.hpp"
  
! #ifndef PRODUCT
! 
! #include "utilities/globalDefinitions.hpp"
! // Unit tests
! 
! bool arrayOopDesc::check_overflow(BasicType type) {
!   int32_t length = max_array_length(type);
!   size_t bytes_per_element = type2aelembytes(type);
!   size_t bytes = (size_t)length * bytes_per_element + header_size_in_bytes();
!   return (bytes - header_size_in_bytes()) / bytes_per_element == (size_t)length;
! }
! 
! // The old implementation of max_array_length. For 64-bit platforms the old
! // and new implementations should return the same value.
! int32_t arrayOopDesc::old_max_array_length(BasicType type) {
!    const int bytes_per_element = type2aelembytes(type);
!     if (bytes_per_element < HeapWordSize) {
!       return max_jint;
!     }
!     const int32_t max_words = align_size_down(max_jint, MinObjAlignment);
!     const int32_t max_element_words = max_words - header_size(type);
!     const int32_t words_per_element = bytes_per_element >> LogHeapWordSize;
!     return max_element_words / words_per_element;
! }
! 
! bool arrayOopDesc::test_max_array_length() {
!   tty->print_cr("test_max_array_length");
!   
!   assert(check_overflow(T_BOOLEAN), "size_t overflow for boolean array");
!   assert(check_overflow(T_CHAR), "size_t overflow for char array");
!   assert(check_overflow(T_FLOAT), "size_t overflow for float array");
!   assert(check_overflow(T_DOUBLE), "size_t overflow for double array");
!   assert(check_overflow(T_BYTE), "size_t overflow for byte array");
!   assert(check_overflow(T_SHORT), "size_t overflow for short array");
!   assert(check_overflow(T_INT), "size_t overflow for int array");
!   assert(check_overflow(T_LONG), "size_t overflow for long array");
!   assert(check_overflow(T_OBJECT), "size_t overflow for object array");
!   assert(check_overflow(T_ARRAY), "size_t overflow for array array");
!   assert(check_overflow(T_NARROWOOP), "size_t overflow for narrowOop array");
! 
!   // T_VOID and T_ADDRESS are not supported by max_array_length()
! 
! #ifdef _LP64
!   assert(max_array_length(T_BOOLEAN) == old_max_array_length(T_BOOLEAN), "calculation changed for boolean");
!   assert(max_array_length(T_CHAR) == old_max_array_length(T_CHAR), "calculation changed for char");
!   assert(max_array_length(T_FLOAT) == old_max_array_length(T_FLOAT), "calculation changed for float");
!   assert(max_array_length(T_DOUBLE) == old_max_array_length(T_DOUBLE), "calculation changed for double");
!   assert(max_array_length(T_BYTE) == old_max_array_length(T_BYTE), "calculation changed for byte");
!   assert(max_array_length(T_SHORT) == old_max_array_length(T_SHORT), "calculation changed for short");
!   assert(max_array_length(T_INT) == old_max_array_length(T_INT), "calculation changed for int");
!   assert(max_array_length(T_LONG) == old_max_array_length(T_LONG), "calculation changed for long");
!   assert(max_array_length(T_OBJECT) == old_max_array_length(T_OBJECT), "calculation changed for object");
!   assert(max_array_length(T_ARRAY) == old_max_array_length(T_ARRAY), "calculation changed for array");
!   assert(max_array_length(T_NARROWOOP) == old_max_array_length(T_NARROWOOP), "calculation changed for narrowOop");
! #endif
! 
!   return true;
! }
! 
! 
! #endif //PRODUCT