RFR: 8261480: MetaspaceShared::preload_and_dump should check exceptions [v4]

Ioi Lam iklam at openjdk.java.net
Wed Mar 17 18:08:04 UTC 2021


> `MetaspaceShared::preload_and_dump()`, as well as many of the functions that it calls, have extensive use of `THREAD` when calling functions that can potentially throw exceptions. Many of these call sites explicitly check for failure status, or assume that the caller would terminate the VM if an exception were to happen. This makes the code hard to understand and potentially unsafe.
> 
> I have make 3 types of changes:
> 
> 1. In most cases, replace THREAD with CHECK. Moved all the fatal error check to `MetaspaceShared::preload_and_dump()`, where it handles any uncaught exceptions and explicitly terminates the VM.
> 2. If a `TRAPS` function can never throw, replace the `TRAPS` declaration with `Thread* current`
> 3. In cases where an exception is handled and discarded, use `THREAD` immediately followed by  `HAS_PENDING_EXCEPTION` -> `CLEAR_PENDING_EXCEPTION` to make the code easy to understand. HandleMark is used to assert that no exception escapes.
> 
> (See `MetaspaceShared::try_link_class` for an example of 2 and 3).
> 
> Tested with tiers 1-4.

Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:

  @calvinccheung comments: restored PerfClassTraceTime

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2925/files
  - new: https://git.openjdk.java.net/jdk/pull/2925/files/336e8d07..1c87518e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2925&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2925&range=02-03

  Stats: 8 lines in 1 file changed: 7 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2925.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2925/head:pull/2925

PR: https://git.openjdk.java.net/jdk/pull/2925


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