[lldb] Fix LLDBMemoryReader resolving GOT pointers incorrectly #11687
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| // The segment/section pair has to be: | ||
| //__DATA_CONST,__got, __AUTH_CONST,__auth_got or __AUTH_CONST,__auth_ptr. | ||
| bool is_data_const_got = | ||
| segment->GetName() == "__DATA_CONST" && section->GetName() == "__got"; |
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This should be a virtual function — if we can avoid it we shouldn't hardcode the name/segment of the GOT here, but rather in ObjectFileMachO.h
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I added a new commit with this code which I will upstream after this is merged
A global offset table is a section that holds the address of functions that are dynamically linked. rdar://160837587
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adrian-prantl
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Oct 24, 2025
| bool ContainsOnlyDebugInfo() const; | ||
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| /// Returns true if this is a global offset table section. | ||
| bool IsGOTSection() const; |
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Please upstream this afterwards!
The DYLD shared cache, as an optimization, can merge GOT pointers from multiple images into one location, and fix all relative offsets to point to the new updated location. When reading metadata, LLDB tries, as an optimization, to read memory from local files instead of live memory. This means that the relative offset will point to the old location in the GOT section. In this case, LLDB needs to re-read the offset from live memory, to get the correct offset in live memory. rdar://160837587
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The DYLD shared cache, as an optimization, can merge GOT pointers from multiple images into one location, and fix all relative offsets to point to the new updated location. When reading metadata, LLDB tries, as an optimization, to read memory from local files instead of live memory. This means that the relative offset will point to the old location in the GOT section. In this case, LLDB needs to re-read the offset from live memory, to get the correct offset in live memory.
rdar://160837587