RFR: 8257794: Zero: assert(istate->_stack_limit == istate->_thread->last_Java_sp() + 1) failed: wrong on Linux/x86_32 [v3]

[Jie Fu]

> Hi all,
> 
> Zero debug build on Linux/x86_32 is broken due to an incorrect assert [1].
> 
> 'istate->_stack_limit' is set here [2] as 'stack->sp() - 1'.
> 'istate->_thread->last_Java_sp()' is set here [3], which is actually 'stack->sp()' according to [4].
> 
> So the correct assert should be:
>   assert(istate->_stack_limit == istate->_thread->last_Java_sp() - 1)
> 
> It would be better to fix it.
> 
> Testing:
>    - Zero fastdebug build passed on Linux/x86_32
> 
> Thanks.
> Best regards,
> Jie
> 
> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/share/interpreter/zero/bytecodeInterpreter.cpp#L422
> [2] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/zero/zeroInterpreter_zero.cpp#L819
> [3] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/zero/zeroInterpreter_zero.cpp#L194
> [4] https://github.com/openjdk/jdk/blob/master/src/hotspot/os_cpu/linux_zero/thread_linux_zero.hpp#L65

Jie Fu has updated the pull request incrementally with one additional commit since the last revision:

  Remove the assert

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1637/files
  - new: https://git.openjdk.java.net/jdk/pull/1637/files/633034a3..34e35cc4

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1637&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1637&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1637.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1637/head:pull/1637

PR: https://git.openjdk.java.net/jdk/pull/1637