> When regenerating > `test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestMismatchHandling.jcod`, > the preload attribute are back, after being removed in [8325660: [lworld] > Update C2 to support new value construction scheme from JEP > 401](https://bugs.openjdk.org/browse/JDK-8325660). This change basically > disabled the test > `test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestMismatchHandling.java`. > It is not quite clear why the test broke in between, but it doesn't work now! > It seems there are two problems. > > The symptom is a wrong execution: we get a null pointer exception, when the > pointer is clearly not null. The setup is around a call where the callee > takes a value object as parameter (non-receiver), but the method happens to > be mismatch, as detailed in [8301007: [lworld] Handle mismatches of the > preload attribute in the calling > convention](https://bugs.openjdk.org/browse/JDK-8301007). The caller is > C2-compiled, the callee is interpreted. > > The caller is correctly compiled to pass a pointer to the callee, but the > adapter is expecting a scalar convention, and interpret everything wrong, > leading to the wrong execution. > > First problem is that optimized virtual calls are wrongly expected to never > use the non-scalar convention: > https://github.com/openjdk/valhalla/blob/lworld/src/hotspot/share/runtime/sharedRuntime.cpp#L1374-L1376 > > This fixes the original problems, but create a lot more! Well, just flavor of > the same thing. > > They all come from piggybacking on the `evol_method` dependency that is used > for JVMTI. This have various side effects that makes the code fail assertions > a bit everywhere. Overall, dependencies coming from breakpoints are confused > with some coming from mismatch calling convention, and some functions are > used in both context, but not all. For instance (I might be a blurry on the > details), it happens that a function is marked as having a mismatch calling > convention, but later, some JVMTI related code will read the dependency as > the existence of breakpoints (or something related), and refuse to compile > it, making the test fail with `AbortVMOnCompilationFailure`. Distinguishing > the cases becomes too complicated: while we can probably tell whether we > added the dependency for JVMTI- or convention-related reasons, it is painful > to propagate what we are looking for down the chain of calls. The best, and > simplest, way is to introduce a new kind of dependency for calling convention > mismatch . It mostly behaves live the `evol_method` but it's not the sa...
Marc Chevalier has updated the pull request incrementally with two additional commits since the last revision: - comment - review ------------- Changes: - all: https://git.openjdk.org/valhalla/pull/1677/files - new: https://git.openjdk.org/valhalla/pull/1677/files/524be8bc..c7c14ec7 Webrevs: - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1677&range=01 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1677&range=00-01 Stats: 26 lines in 7 files changed: 6 ins; 1 del; 19 mod Patch: https://git.openjdk.org/valhalla/pull/1677.diff Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1677/head:pull/1677 PR: https://git.openjdk.org/valhalla/pull/1677
