What Do You Think? JDK-8213084: Rework and enhance Print[Opto]Assembly output

[Andrew Haley]

On 11/28/18 4:16 PM, Schmidt, Lutz wrote:

> Looking forward to your comments, whatever they may be. And, please, cross-post to other lists if you see a requirement.

Current:

----------------------------------------------------------------------------------------------------
;; B3: #       B112 B4 <- B2  Freq: 0.999979

  0x00007f2cdfd26d08: mov    (%rsp),%r10
  0x00007f2cdfd26d0c: mov    0x4c(%r10),%r9d                ;*getfield htab {reexecute=0 rethrow=0 return_oop=0}
                                                            ; - spec.benchmarks._201_compress.Compressor::compress at 15

  0x00007f2cdfd26d10: mov    0xc(%r9),%r11d                 ;*getfield size {reexecute=0 rethrow=0 return_oop=0}
                                                            ; - spec.benchmarks._201_compress.Compressor::compress at 22
                                                            ; implicit exception: dispatches to 0x00007f2cdfd27383
----------------------------------------------------------------------------------------------------
Yours:

----------------------------------------------------------------------------------------------------
;; block B3: # (out B115 B4 <- (in B2 )) Freq: 0.999979
  0x00007fe1b77ff364 (+0x0044): mov    0x4c(%rbp),%r10d         ;*getfield htab {reexecute=0 rethrow=0 return_oop=0}
                                                                ; - spec.benchmarks._201_compress.Compressor::compress at 15
  0x00007fe1b77ff368 (+0x0048): mov    0xc(%r10),%r8d           ;*getfield size {reexecute=0 rethrow=0 return_oop=0}
                                                                ; - spec.benchmarks._201_compress.Compressor::compress at 22
                                                                ; implicit exception: dispatches to 0x00007fe1b77ffdfa
----------------------------------------------------------------------------------------------------


Current is better than Yours, IMO. Vertical whitespace is good, please don't
lose it.

Your constant pool output is extremely verbose, and this is not an improvement.
There must be some compromise.

Whenever you add more detail, there is always the risk of hiding what is
essential. Why this:

;; block B3: # (out B115 B4 <- (in B2 )) Freq: 0.999979

rather than

;; B3: #       B112 B4 <- B2  Freq: 0.999979

?

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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