[lworld] RFR: 8335256: [lworld] compiler/valhalla/inlinetypes/TestValueConstruction.java fails intermittently

[Quan Anh Mai]

Hi,

The assert fires because in this place:

    if (is_osr_parse()) {
      Node* osr_buf = entry_map->in(TypeFunc::Parms+0);
      entry_map->set_req(TypeFunc::Parms+0, top());
      set_map(entry_map);
      load_interpreter_state(osr_buf);
    } else {
      set_map(entry_map);
      do_method_entry();
    }

`load_interpreter_state` assumes that all incoming inline types are non-larval, while in the following place:

    if (t->is_inlinetypeptr()) {
      // Create InlineTypeNode from the oop and replace the parameter
      bool is_larval = (i == 0) && method()->is_object_constructor() && !method()->holder()->is_java_lang_Object();
      Node* vt = InlineTypeNode::make_from_oop(this, parm, t->inline_klass(), !t->maybe_null(), is_larval);
      replace_in_map(parm, vt);
    }

`is_larval == true` because we are osr-compiling the constructor of a value class. As a result, we pass a non-larval object into `InlineTypeNode::make_from_oop` and want to make it larval, triggering the assert.

Thinking more deeply into this, I think there is no way we can know the larval-ness of an incoming object in an osr-compilation unless `ciTypeFlow` does so. For example, consider this bytecode sequence:

    ValueObject x = new ValueObject;
    for {
    }
    x.<init>();

Then, when we osr-compile the method from the loop, `x` will be a larval object and it can be at any place on the JVM stack or in the local slots.

As a result, I propose optimistically assuming all osr parameters be non-larval, then we can change them to larval when encountering a constructor invocation or a field store instruction. The verifier should ensure that we cannot do anything else on a larval object as well as do these actions on a non-larval object, so we should recognize the correct state of the value object if any operation is performed on them. Otherwise, they should be dead and not apear here.

Please take a look and give your advices, thanks a lot.

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

Commit messages:
 - Fix osr inline type parameter

Changes: https://git.openjdk.org/valhalla/pull/1358/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1358&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8335256
  Stats: 69 lines in 5 files changed: 55 ins; 7 del; 7 mod
  Patch: https://git.openjdk.org/valhalla/pull/1358.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1358/head:pull/1358

PR: https://git.openjdk.org/valhalla/pull/1358