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8315771: [JVMCI] Resolution of bootstrap methods with int[] static arguments #15588

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8315771: [JVMCI] Resolution of bootstrap methods with int[] static arguments #15588

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b0940de
Implement lookup of bootstrap methods with static arguments of type i…
Zeavee Sep 6, 2023
2cdc0b4
Rewrite doc for bootstrapArgumentIndexAt and add second argument to a…
Zeavee Sep 6, 2023
b33ffed
Add more details to the documentation and add a pseudo code example f…
Zeavee Sep 7, 2023
093d0ce
Add missing line of pseudo code and applied modification suggestion
Zeavee Sep 7, 2023
4ec0a7b
Add CachedBSMArgs to resolve arguments lazily instead of letting the …
Zeavee Sep 7, 2023
079969c
Fix BootstrapMethodInvocation.getStaticArguments documentation and ad…
Zeavee Sep 8, 2023
d6aa593
Use lookupConstant instead of lookupConstantInPool in CachedBSMArgs.get
Zeavee Sep 13, 2023
d75e092
Add undefined behavior documentation for bootstrapArgumentIndexAt and…
Zeavee Sep 13, 2023
f4377fc
Update getStaticArguments documentation example and update TestDynami…
Zeavee Sep 14, 2023
9e0627a
Add -XX:UseBootstrapCallInfo=3 to TestDynamicConstant
Zeavee Sep 19, 2023
ea4aa98
Add an extra run configuration for TestDynamicConstant instead of rep…
Zeavee Sep 19, 2023
7c27481
Update BootstrapMethodInvocation.getStaticArguments documentation
Zeavee Sep 20, 2023
7a8d9f2
Iterate over all static arguments in TestDynamicConstant
Zeavee Sep 21, 2023
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17 changes: 17 additions & 0 deletions src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/hotspot/HotSpotConstantPool.java
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Original file line number Diff line number Diff line change
Expand Up @@ -529,6 +529,12 @@ private int flags() {
return UNSAFE.getInt(getConstantPoolPointer() + config().constantPoolFlagsOffset);
}

/**
* Represents a list of static arguments from a {@link BootstrapMethodInvocation} of the form
* {{@code arg_count}, {@code pool_index}}, meaning the arguments are not already resolved
* and that the JDK has to lookup the arguments when they are needed. The {@code bssIndex}
* corresponds to {@code pool_index} and the {@code size} corresponds to {@code arg_count}.
*/
static class CachedBSMArgs extends AbstractList<JavaConstant> {
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This class needs documentation.

private final JavaConstant[] cache;
private final HotSpotConstantPool cp;
Expand All @@ -540,6 +546,17 @@ static class CachedBSMArgs extends AbstractList<JavaConstant> {
this.cache = new JavaConstant[size];
}

/**
* Lazily resolves and caches the argument at the given index and returns it. The method
* {@link CompilerToVM#bootstrapArgumentIndexAt} is used to obtain the constant pool
* index of the entry and the method {@link CompilerToVM#lookupConstantInPool} is used
* to resolve it. If the resolution failed, the index is returned as a
* {@link PrimitiveConstant}.
*
* @param index index of the element to return
* @return A {@link PrimitiveConstant} representing a {@code CONSTANT_Dynamic_info}
* entry or a {@link JavaConstant} representing the static argument requested
*/
@Override
public JavaConstant get(int index) {
JavaConstant res = cache[index];
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21 changes: 13 additions & 8 deletions src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/meta/ConstantPool.java
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Expand Up @@ -169,19 +169,24 @@ interface BootstrapMethodInvocation {
* entry. To resolve this entry, the corresponding bootstrap method has to be called first:
*
* <pre>
* resolveIndyOrCondy(int index, int opcode) {
* bsmInvocation = cp.lookupBootstrapMethodInvocation(index, opcode);
* staticArguments = bsmInvocation.getStaticArguments();
* for each argument in staticArguments {
* if argument is PrimitiveArgument {
* // argument is a condy, so opcode becomes -1
* resolveIndyOrCondy(argument.asInt(), -1);
* lookupConstant(int index, boolean resolve) {
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This example should focus on resolving the static arguments:

List<JavaConstant> args = cp.getStaticArguments();
List<JavaConstant> resolvedArgs = new ArrayList<>(args.size());
for (JavaConstant c : args) {
    JavaConstant r = c;
    if (c instanceof PrimitiveConstant pc) {
        r = ...
    }
    resolvedArgs.append(rc);
}

It should also use real Java code to remove all ambiguity.

* constant = cp.lookupConstant(index, resolve);
* if constant is null {
* bsmInvocation = cp.lookupBootstrapMethodInvocation(index, -1);
* staticArguments = bsmInvocation.getStaticArguments();
* for each argument in staticArguments {
* if argument is PrimitiveArgument {
* lookupConstant(argument.asInt(), resolve);
* }
* }
* call boostrap method with resolved arguments to get constant
* }
* call original boostrap method with resolved arguments
* return constant;
* }
* </pre>
*
* The other types of entries are already resolved an can be used directly.
*
* @jvms 5.4.3.6
*/
List<JavaConstant> getStaticArguments();
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