POC: Retrieve the actual alignment of max_align_t
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The code had a hard-coded maximum alignment of 16 (128 bits) which may have potentially wasted memory and cause memory unsafety if it was ever compiled with larger alignment (unlikely). This change implements a trick to retrieve the actual alignment from C. To achieve this a newly added C file defines a symbol initialized to `_Alignof(max_align_t)`. It is then compiled (as a separate object), the contents of the symbol is extracted and converted to decimal string which is injected into the `AlignedType` definition. The definition is generated as a separate `.rs` file in `OUT_DIR` and included into `types.rs`.
Kixunil
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Hah, clever! Do you think we could just make the C code |
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We can't because the binary would be produced for target (to have the correct |
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The code had a hard-coded maximum alignment of 16 (128 bits) which may have potentially wasted memory and cause memory unsafety if it was ever compiled with larger alignment (unlikely).
This change implements a trick to retrieve the actual alignment from C. To achieve this a newly added C file defines a symbol initialized to
_Alignof(max_align_t). It is then compiled (as a separate object), the contents of the symbol is extracted and converted to decimal string which is injected into theAlignedTypedefinition. The definition is generated as a separate.rsfile inOUT_DIRand included intotypes.rs.This POC currently doesn't support cross-compilation which I intend to fix, I just wanted to show that it's possible to do this. Do we want to?