JDK-8146547 : String copy intrinsics should zero array in case of tightly coupled allocation
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 9,10
  • Priority: P5
  • Status: Open
  • Resolution: Unresolved
  • Submitted: 2016-01-06
  • Updated: 2020-05-07
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Other
tbdUnresolved
Related Reports
Duplicate :  
JDK-8139132 - CompactStrings intrinsics should use ArrayCopyNode
Relates :  
JDK-8054307 - JEP 254: Compact Strings
Description
LibraryCallKit::inline_string_copy() and LibraryCallKit::inline_string_getCharsU() use LibraryCallKit::tightly_coupled_allocation() to skip zeroing the array elements of a tightly coupled array allocation. However, the intrinsics do not take care of zeroing remaining array elements not affected by the intrinsic operation.
Currently, this is not a problem because all (String API internal) usages of the intrinsics that have a tightly coupled allocation make sure that the entire array is initialized. However, we should fix this to avoid potential bugs.
Comments
ILW = potential risk of uninitialized wth 0 arrays in String internals; no cases with failures; manual zeroing of arrays = MLL = P5
06-04-2016