[jdk18] RFR: 8278413: C2 crash when allocating array of size too large

[Roland Westrelin]

On the fallthrough path from an AllocateArray, the length of the
allocated array is casted (with a CastII) to [0, max_size] with
max_size some number that depends on the array type and can be less
than max_jint.

Allocating an array of a length that's not in [0, max_size] causes the
CastII to become top. The fallthrough path must be killed as well in
that case otherwise this can lead to a broken graph. Currently c2 has
logic to protect against an allocation of array of negative size in
AllocateArrayNode::Ideal(). That call replaces the fallthrough path
with an Halt node. But if the size is too big, then the fallthrough
path is left as is.

This patch fixes that issues. It also reworks the length negative
case. I added a Bool/CmpU input to the AllocateArray that tests for a
valid length. If that input becomes false, CatchNode::Value() kills
the fallthrough path. That logic is similar to that for a virtual call
with a null receiver. I also removed AllocateArrayNode::Ideal() now
that CatchNode::Value() takes care of the same corner case. The code
in AllocateArrayNode::Ideal() was added by Vladimir and he told me he
tried extending CatchNode::Value() at the time but that caused test
failures. I had no issues in my testing so I assume doing it that way
is ok now.

The new input to AllocateArray is moved to the CallStaticJava runtime
call for array allocation on macro expansion as a precedence edge. The
reason for that is that final graph reshape needs a way to tell
whether the missing path out of the allocation is legal or not. final
graph reshape then removes the then useless precedence edge.

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Commit messages:
 - alloc array fix

Changes: https://git.openjdk.java.net/jdk18/pull/30/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk18&pr=30&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278413
  Stats: 200 lines in 9 files changed: 125 ins; 53 del; 22 mod
  Patch: https://git.openjdk.java.net/jdk18/pull/30.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk18 pull/30/head:pull/30

PR: https://git.openjdk.java.net/jdk18/pull/30