[lworld] RFR: 8228634: [lworld] ciField::will_link() returns incorrect result for the withfield bytecode

Tobias Hartmann thartmann at openjdk.java.net
Fri Dec 11 13:11:22 UTC 2020


In `GraphBuilder::withfield`, `ciField::will_link()` can return false even if the holder klass is loaded (see bug comments). In that case we should not deoptimize but patch the store instruction that writes the new field value. That is required even if the field offset is known because the field could not be accessible/available and we would need to throw an exception during patching. The load/store instructions emitted by `copy_inline_content` to initialize the fields of the new inline type buffer copy should never require patching: We know their offsets (because the holder is loaded) and we don't need to check access restrictions.

Unrelated changes:
- Array loads should not be delayed if the subsequent getfield requires patching (see changes to `GraphBuilder::load_indexed`)
- Replaced the `WithField` and `DefaultValue` IR nodes by a `Deoptimize` node
- Refactoring and removal of dead code

Thanks,
Tobias

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

Commit messages:
 - Should save state before popping from stack
 - 8228634: [lworld] ciField::will_link() returns incorrect result for the withfield bytecode

Changes: https://git.openjdk.java.net/valhalla/pull/301/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=301&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8228634
  Stats: 191 lines in 15 files changed: 30 ins; 97 del; 64 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/301.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/301/head:pull/301

PR: https://git.openjdk.java.net/valhalla/pull/301


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