RFR: 8357660: [JVMCI] Add Support for Retrieving All Indy BootstrapMethodInvocations directly from the ConstantPool

[Doug Simon]

On Tue, 27 May 2025 14:07:21 GMT, Tom Shull <duke at openjdk.org> wrote:

> Would you want me to add a reference

The main point is that resolving can execute Java code (as far as I recall) so cannot be called from a CompileBroker thread as these threads must not call Java code. However, I see that this constraint is not currently documented so it ok to leave it out for now.

>> src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/meta/ConstantPool.java line 237:
>> 
>>> 235:      * is returned.
>>> 236:      */
>>> 237:     BootstrapMethodInvocation[] lookupAllIndyBootstrapMethodInvocations();
>> 
>> Why not make this return all `BootstrapMethodInvocation`s? The caller can then filter out the indy ones with `isInvokeDynamic`. Also, please return a `List<BootstrapMethodInvocation>` instead of an array - we should never return arrays from JVMCI (see #23159 as an example of addressing existing API). Lastly, return `List.of()` instead of null.
>
> Changed to return a list.
> 
>> Why not make this return all BootstrapMethodInvocations
> 1. Within HotSpot it is very easy to pick off all indy BootstrapMethodInvocations via [the ConstantPoolCache](https://github.com/openjdk/jdk/blob/72a3022dc6a1521d8e3f08fe5d592f760fc462d2/src/hotspot/share/oops/cpCache.hpp#L74)
> 2. Each invokedynamic bytecode location has a unique BootstrapMethodInvocation instance, but they may share the same constant pool entry, so it's not trivial to find all BootstrapMethodInvocations. One would have to iterate both all method bytecodes and constant pool slots, and do some additional filtering.

How about `List<BootstrapMethodInvocation> lookupBootstrapMethodInvocations(boolean indy)`? That is, it either gets the indy *or* the condy BSM invocations. I can imagine SVM wanting the latter at some point right?

BTW, I noticed that the javadoc for `ConstantPool.lookupBootstrapMethodInvocation` is somewhat incorrect. Please check and apply these corrections in this PR:

diff --git a/src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/meta/ConstantPool.java b/src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/meta/ConstantPool.java
index 2273b256f03..3519af4bcbb 100644
--- a/src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/meta/ConstantPool.java
+++ b/src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/meta/ConstantPool.java
@@ -199,12 +199,12 @@ interface BootstrapMethodInvocation {
      * in the constant pool.
      *
      * @param index if {@code opcode} is -1,  {@code index} is a constant pool index. Otherwise {@code opcode}
-     *              must be {@code Bytecodes.INVOKEDYNAMIC}, and {@code index} must be the operand of that
-     *              opcode in the bytecode stream (i.e., a {@code rawIndex}).
-     * @param opcode must be {@code Bytecodes.INVOKEDYNAMIC}, or -1 if
+     *              must be {@code Bytecodes.INVOKEDYNAMIC} or {@code CONSTANT_Dynamic_info}, and {@code index}
+     *              must be the operand of that opcode in the bytecode stream (i.e., a {@code rawIndex}).
+     * @param opcode must be {@code Bytecodes.INVOKEDYNAMIC}, {@code CONSTANT_Dynamic_info}, or -1 if
      *            {@code index} was not decoded from a bytecode stream
      * @return the bootstrap method invocation details or {@code null} if the entry specified by {@code index}
-     *         is not a {@code CONSTANT_Dynamic_info} or @{code CONSTANT_InvokeDynamic_info}
+     *         is not a {@code CONSTANT_Dynamic_info} or {@code CONSTANT_InvokeDynamic_info}
      * @jvms 4.7.23 The {@code BootstrapMethods} Attribute
      */
     default BootstrapMethodInvocation lookupBootstrapMethodInvocation(int index, int opcode) {

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

PR Review Comment: https://git.openjdk.org/jdk/pull/25420#discussion_r2109436288
PR Review Comment: https://git.openjdk.org/jdk/pull/25420#discussion_r2109450651