8359920: Use names for frame types in stackmaps

[coleenp]

This uses names for frame types for stackmaps in the verifier and redefinition.
Tested with tier1-7.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8359920: Use names for frame types in stackmaps (Enhancement - P4)

Reviewers

• Johan Sjölen (@jdksjolen - Reviewer) 🔄 Re-review required (review applies to 37b5c7ee)
• Matias Saavedra Silva (@matias9927 - Reviewer) 🔄 Re-review required (review applies to 37b5c7ee)
• Serguei Spitsyn (@sspitsyn - Reviewer) 🔄 Re-review required (review applies to 37b5c7ee)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/25870/head:pull/25870
$ git checkout pull/25870

Update a local copy of the PR:
$ git checkout pull/25870
$ git pull https://git.openjdk.org/jdk.git pull/25870/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 25870

View PR using the GUI difftool:
$ git pr show -t 25870

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/25870.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back coleenp! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@coleenp This change is no longer ready for integration - check the PR body for details.

[openjdk]

@coleenp The following labels will be automatically applied to this pull request:

• hotspot
• serviceability

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 03: Full - Incremental (7d2e60c2)
• 02: Full - Incremental (107382e4)
• 01: Full - Incremental (c3d8d0fc)
• 00: Full (37b5c7ee)

[matias9927]

LGTM, thanks!

[dholmes-ora]

I find these definitions a little confusing. SAME_FRAME is actually 0-63, with SAME_LOCALS_1_STACK_ITEM_FRAME being 64-127. Given many of these frame types imply tag ranges it may be clearer to define enum's for the start and end of ranges as applicable eg.

enum {
  SAME_FRAME_START = 0,
  SAME_FRAME_END = 63,
  SAME_LOCALS_1_STACK_ITEM_FRAME_START = 64,
  SAME_LOCALS_1_STACK_ITEM_FRAME_END = 127,
  RESERVED_START = 128,
  RESERVED_END = 246,
  SAME_LOCALS_1_STACK_ITEM_EXTENDED = 247,
  CHOP_FRAME_START = 248,
  CHOP_FRAME_END = 250,
  SAME_FRAME_EXTENDED = 251,
  APPEND_FRAME_START = 252,
  APPEND_FRAME_END = 254,
  FULL_FRAME = 255
}

and then adjust the code usage as appropriate e.g.

if (frame_type <= SAME_FRAME_END) {
...
if (frame_type <= SAME_LOCALS_1_STACK_ITEM_FRAME_END) {
  if (_first) {
    offset = frame_type - SAME_LOCALS_1_STACK_ITEM_FRAME_START;
...

What do you think?

[coleenp]

I wasn't really up for a big rewrite but having the complete set of names would be really good.

[sspitsyn]

This looks good.
I was also thinking about frame_type ranges but no ideas on any improvements.