Add storage, retrieval of AOT method dependencies #20581
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Attn @mpirvu. This is just the dependency storage/retrieval implementation. I've mentioned before that I was storing the offset to the dependencies next to the well-known classes offset, in the relocation record header. That happens starting here. While I was doing that previously, I believe this conflicts with AOT method compression in the SCC - I'd have to decompress the stored data just to read off the offset, because the relocation records are compressed as well. I've chosen not to store the dependency offset in the compiled body at all, and instead look up the dependencies by key when I need them. Alternatively, I could store the dependency chain offset in the AOT method header itself. |
| cursor += dependencyKeyPrefixLength; | ||
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| convertUnsignedOffsetToASCII(offset, cursor); | ||
| keyLength = (cursor - buffer) + _numDigitsForCacheOffsets + 1; // NULL terminator not included in _numDigitsForCacheOffsets |
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So the keyLength includes the NULL terminator
| * The dependencies of an AOT method are encoded as an array of uintptr_t values. The first entry is the number | ||
| * of elements in the entire array. The subsequent entries are encoded offsets to the class chains of classes that | ||
| * need to be loaded or initialized before the compiled body can be loaded. The entry will be the offset itself | ||
| * if the class must be initialized, and it will be (offset & ~1) if the class only needs to be loaded. |
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I don't understand the comment. Do you erase the last bit or set the last bit?
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I erase the last bit. Class chain offsets always have their last bit set. I've clarified.
cjjdespres
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jenkins compile all jdk21 |
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One build error: The imports must be slightly different on aarch64_mac. |
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I think |
When the dependencies of compiled AOT method bodies are tracked, they will be stored in the SCC as arrays of uintptr_t values, with the first entry being the length of the array, and the subsequent entries being encoded class chain offsets. The low bit of the class chain offset will be cleared if the corresponding class merely needs to be loaded before the compiled method body in the SCC can be loaded. This infrastructure is currently unused. Signed-off-by: Christian Despres <[email protected]>
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jenkins compile all jdk21 |
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The new code is not executed, so compile tests are sufficient. |
When the dependencies of compiled AOT method bodies are tracked, they will be stored in the SCC as arrays of uintptr_t values, with the first entry being the length of the array, and the subsequent entries being encoded class chain offsets. The low bit of the class chain offset will be cleared if the corresponding class merely needs to be loaded before the compiled method body in the SCC can be loaded.
This infrastructure is currently unused.
Related: #20529