8160404: RelocationHolder constructors have bugs

[bulasevich]

This change is a clean and self-contained bug fix. It’s beneficial to backport it independently to jdk17u.

Also I would like to backport other related changes that depend (transitively) on this one:

• JDK 8321509: False positive in get_trampoline fast path causes crash
  • JDK-8298913: Add override qualifiers to Relocation classes
    • JDK-8160404: RelocationHolder constructors have bugs

This is not a clean backport. The original patch also modifies the post_call_nop_Relocation and entry_guard_Relocation classes, which are part of:

• 8284161: Implementation of Virtual Threads (Preview)
• 8290700: Optimize AArch64 nmethod entry barriers

I do not expect these changes to be backported to jdk17u, so I have excluded those parts in this backport:

@@ -935,29 +996,29 @@ class DataRelocation : public Relocation {
 };

 class post_call_nop_Relocation : public Relocation {
-  friend class RelocIterator;
+  friend class RelocationHolder;

 public:
   post_call_nop_Relocation() : Relocation(relocInfo::post_call_nop_type) { }

   static RelocationHolder spec() {
-    RelocationHolder rh = newHolder();
-    new(rh) post_call_nop_Relocation();
-    return rh;
+    return RelocationHolder::construct<post_call_nop_Relocation>();
   }
+
+  void copy_into(RelocationHolder& holder) const;
 };

 class entry_guard_Relocation : public Relocation {
-  friend class RelocIterator;
+  friend class RelocationHolder;

 public:
   entry_guard_Relocation() : Relocation(relocInfo::entry_guard_type) { }

   static RelocationHolder spec() {
-    RelocationHolder rh = newHolder();
-    new(rh) entry_guard_Relocation();
-    return rh;
+    return RelocationHolder::construct<entry_guard_Relocation>();
   }
+
+  void copy_into(RelocationHolder& holder) const;
 };

 // A CallRelocation always points at a call instruction.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8160404 needs maintainer approval

Issue

• JDK-8160404: RelocationHolder constructors have bugs (Bug - P4) ⚠️ Issue is already resolved. Consider making this a "backport pull request" by setting the PR title to Backport <hash> with the hash of the original commit. See Backports.

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk17u-dev.git pull/3513/head:pull/3513
$ git checkout pull/3513

Update a local copy of the PR:
$ git checkout pull/3513
$ git pull https://git.openjdk.org/jdk17u-dev.git pull/3513/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 3513

View PR using the GUI difftool:
$ git pr show -t 3513

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk17u-dev/pull/3513.diff

[bridgekeeper]

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[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.