RFR: 8294492: RISC-V: Use li instead of patchable movptr at non-patchable callsites [v3]

[Xiaolin Zheng]

> A cleanup which can also reduce some code size. The main purpose is to separate the current mixed movptr usages: movptr's semantics allow it to be used for fixed-length patchable addresses. In the current backend several callsites which are not patchable use movptr (6 instructions) as well, but that's unnecessary for we can use li(1~6 instructions) to substitute them.
> 
> This patch extracts the last 12-bit offset from the li(), a recursive function, to merge it into the rest "jalr/ld/sd..." that can accept a 12-bit offset as an operand, same as the movptr_with_offset before.
> 
> Originally some non-patchable callsites:
> 
> ;; 0x401ab1dc40
> 0x000000401372b324:   lui	t0,0x201
> 0x000000401372b328:   addi	t0,t0,-680 # 0x0000000000200d58
> 0x000000401372b32c:   slli	t0,t0,0xb
> 0x000000401372b32e:   addi	t0,t0,1905
> 0x000000401372b332:   slli	t0,t0,0x6
> 0x000000401372b334:   jalr	t0
> 
> Now:
> 
> 0x000000401b2bd9f4:   lui	t0,0x4003
> 0x000000401b2bd9f8:   addiw	t0,t0,-1275
> 0x000000401b2bd9fc:   slli	t0,t0,0xc
> 0x000000401b2bda00:   jalr	1080(t0) # 0x0000000004003438
> 
> Not so much, but the main purpose is to clarify the usage of movptr and li.
> 
> The first commit has gone through a hotspot tier1~tier4; the other ones are testing under a hotspot tier1.

Xiaolin Zheng has updated the pull request incrementally with one additional commit since the last revision:

  Fix as to comments

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/10462/files
  - new: https://git.openjdk.org/jdk/pull/10462/files/ad15d6b2..4985dcf4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10462&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10462&range=01-02

  Stats: 89 lines in 7 files changed: 16 ins; 57 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/10462.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10462/head:pull/10462

PR: https://git.openjdk.org/jdk/pull/10462