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Re: Auto-generated .rodata contents and __attribute__((section))

On 05/23/2018 02:55 PM, Michael Matz wrote:

On Fri, 18 May 2018, Richard Biener wrote:


Interesting.  Do they allow merging across such sections?  Consider a 8
byte entity 0x12345678 and 4 byte entities 0x1234 0x5678, will the 4
byte entities share the rodata with the 8 byte one?



There's no language to forbid this (as long as the alignments
are respected), but at least GNU ld currently only merges same-sized
entities.
I'm not entirely sure if this is valid for C, particularly if the objects have the same address, but not the same type.
There is a discussion on the generic-abi list about providing information to the linker about when it is safe to do such merging: 

https://groups.google.com/forum/#!topic/generic-abi/MPr8TVtnVn4

Thanks,
Florian
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