8262198: Overhaul bitfield parsing logic

[mcimadamore]

This parsing stratgey cannot (by definition) fail - so, moving forward there will be no more exceptions coming from this side of the code. Of course, since we no longer have container classification, when bitfield support is added to the backend, things might be a bit tricker; however I realized that, since the layout is well-formed, the backend can always use the layout API to query the offset and size of a given bitfield, and decide on the best strategy to get there (e.g. get the closed 8/16/32/64-bit word and apply some bitmasking). So, perhaps things don't change much in terms of code generation support.

This patch fixes a small bug in Parser, where we where creating the same tree twice (!!). There are some small tweaks to TreeMaker, to work with the new bitfield info coming out from RecordLayoutComputer, but overall nothing too difficult here.

Note that the BadBitfieldTest, which was previously asserting a jextract crash, has now turned into a positive test (and I've dropped the exclusion on Windows, since the test should now pass on all platforms).

[1] - rust-lang/rust-bindgen#743

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Progress

• Change must not contain extraneous whitespace
• Change must be properly reviewed

Issue

• JDK-8262198: Overhaul bitfield parsing logic

Reviewers

• Athijegannathan Sundararajan (@sundararajana - Committer) ⚠️ Review applies to e1c2e7f
• Jorn Vernee (@JornVernee - Committer) ⚠️ Review applies to e1c2e7f

Download

$ git fetch https://git.openjdk.java.net/panama-foreign pull/459/head:pull/459
$ git checkout pull/459

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[mlbridge]

Webrevs

• 01: Full - Incremental (400d9f3)
• 00: Full (e1c2e7f)

[sundararajana]

LGTM

[openjdk]

@mcimadamore This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8262198: Overhaul bitfield parsing logic

Reviewed-by: sundar, jvernee

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At the time when this comment was updated there had been 1 new commit pushed to the foreign-jextract branch:

• 6c47c8d: 8262117: jextract crashes with javac compilation error "class u is already defined"

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[mcimadamore]

/integrate

[openjdk]

@mcimadamore Since your change was applied there has been 1 commit pushed to the foreign-jextract branch:

• 6c47c8d: 8262117: jextract crashes with javac compilation error "class u is already defined"

Your commit was automatically rebased without conflicts.

Pushed as commit 6aa7d35.

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