RFR: 8225779: Remove unused CollectedHeap::cell_header_size()

[David Holmes]

Hi Per,

On 14/06/2019 4:29 pm, Per Liden wrote:
> CollectedHeap::cell_header_size() is no longer used and can be removed. 

It seems no longer used simply because you are removing the uses. :)

> This patch is a hg backout of [1] where it was introduced, plus the two 
> followup bug fixes [2] & [3].

Can you explain why you are rolling back:

"8213199: GC abstraction for Assembler::needs_explicit_null_check()"

? Does Shenandoah no longer need it so we can just return to the simpler 
code that existed before?

> This is a clean backout, with the exception of light editing needed in 
> two places, because:
> 
> 1) The function Universe::narrow_oop_base() has since been renamed to 
> CompressedOops::base().
> 2) The include guard CPU_ARM_VM_MACROASSEMBLER_ARM_HPP has since been 
> renamed to CPU_ARM_MACROASSEMBLER_ARM_HPP.

The backout itself looks good.

Thanks,
David
----

> Testing: Tier1-3 on all Oracle platforms
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8225779
> Webrev: http://cr.openjdk.java.net/~pliden/8225779/webrev.0
> 
> /Per
> 
> [1] http://hg.openjdk.java.net/jdk/jdk/rev/4ad404da0088
> [2] http://hg.openjdk.java.net/jdk/jdk/rev/f642ede2eb07
> [3] http://hg.openjdk.java.net/jdk/jdk/rev/18bd95c0e463