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[Local GC] Move knowledge of the free object method table outside of the GC#10755
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swgillespie merged 4 commits intodotnet:masterfrom Apr 9, 2017
Merged
[Local GC] Move knowledge of the free object method table outside of the GC#10755swgillespie merged 4 commits intodotnet:masterfrom
swgillespie merged 4 commits intodotnet:masterfrom
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jkotas
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Apr 6, 2017
src/gc/env/gcenv.ee.h
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| static void HandleFatalError(unsigned int exitCode); | ||
| static bool ShouldFinalizeObjectForUnload(AppDomain* pDomain, Object* obj); | ||
| static MethodTable* GetFreeObjectMethodTable(); | ||
| static size_t GetSizeOfArrayBase(); |
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These constants are used on very perf sensitive paths. I do not think it is ok to virtualize them. They have to be part of the fixed binary contract between VM and GC.
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These methods are called once on GC startup and cached on the GC side - is that still a problem?
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adityamandaleeka
approved these changes
Apr 6, 2017
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Need to resolve conflicts ... LGTM otherwise. |
…side of the GC" This reverts commit 02979e5.
…part of the binary contract between the EE and the GC
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thanks! |
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The EE provides a method table for a specific type of object, the "free object", which is used by the GC to keep the heap crawlable. A free object is conceptually similar to a managed array in that it consists of an object header and a field indicating how many array elements the object has (i.e. how large the free region is), followed by a region of space known to be free to the GC.
This PR ensures that the GC's knowledge of the free method table is acquired through
GCToEEInterfaceupon startup. This PR also has the GC acquire two additional details on startup: 1) the size ofArrayBase, and the 2) offset of theNumComponentsfield ofArrayBase. These are used to locate the offset of the field into which the size of the free object is stored and to locate the first byte of the free object's free region.