Add J9Modules and J9Packages to the VM snapshot #20830
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@babsingh Here is the rest of the preliminary modularity support for the VM snapshot. There are a few areas (in particular) that need improvement (the I've tested on Java 11, and it works (can create a snapshot and restore) provided it is run with |
| UDATA packageNameJ9UTF8Size = packageNameLength + sizeof(J9UTF8) + 1; /* +1 for null-terminator. */ | ||
| #if defined(J9VM_OPT_SNAPSHOTS) | ||
| if (IS_SNAPSHOTTING_ENABLED(vm)) { | ||
| packageName = (J9UTF8 *)vmsnapshot_allocate_memory(packageNameJ9UTF8Size, OMRMEM_CATEGORY_VM); | ||
| } else | ||
| #endif /* defined(J9VM_OPT_SNAPSHOTS) */ | ||
| { | ||
| packageName = (J9UTF8 *)j9mem_allocate_memory(packageNameJ9UTF8Size, OMRMEM_CATEGORY_VM); | ||
| } | ||
| if (NULL == packageName) { | ||
| vmFuncs->setNativeOutOfMemoryError(currentThread, 0, 0); | ||
| return retval; | ||
| } | ||
| memcpy(J9UTF8_DATA(packageName), (void *)package, packageNameLength); | ||
| J9UTF8_DATA(packageName)[packageNameLength] = '\0'; | ||
| J9UTF8_SET_LENGTH(packageName, (U_16)packageNameLength); |
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Why don't we use addUTFNameToPackage over here? We can rewrite addUTFNameToPackage to return packageName, and J9Package->packageName can be set outside the scope this method wherever needed.
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The main other use of addUTFNameToPackage is for setting up queries to the package hash tables. Those names do not need to be persisted (nor properly free'd when freeing a J9Package) and thus they shouldn't be allocated with the vmsnapshot_allocate_memory when snapshotting is enabled.
Given that it is only on creation where J9Package::packageName needs to potentially be allocated in such a way that it can be persisted, and that is only done once in the code base, I figured that an inline version, like implemented here, was more appropriate.
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Ok, let's keep it as-is for now. My initial intent was to aim for a common allocation path to improve maintainability and code clarity, and rely upon the compiler to do the optimizations.
Related: eclipse-openj9#20612 Signed-off-by: Nathan Henderson <[email protected]>
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Related: #20612
Signed-off-by: Nathan Henderson [email protected]