[llvm-dev] [ELF] String literals don't obey -fdata-sections

[Gaël Jobin via llvm-dev]

On 2020-09-16 19:42, Fangrui Song wrote:

> On 2020-09-16, Gaël Jobin wrote: 
> 
> Your example uses global mutable variables "test" and "unused" and that
> is why they are in the .data.* sections. They are initialized to
> addresses of string literals in .rodata.* . .rodata.* are what we care
> about, not .data.* (.data.* can always be correctly garbage collected by
> GNU ld/gold/LLD).

Of course, the issue here is .rodata.*. I use the .data.* section as a
counterexample 
but it could be any section.  I compare those two sections because they
contain both 
 small datas and the ratio "section header size" vs "data size" is not
optimal. 

But my point is: Why the implementation of -fdata-sections should differ
between .data.* 
and .rodata.* sections? Or why .rodata.* should be treated differently? 

If the only reason is because it is suboptimal due to the additional
section header, 
this is definitely not a valid reason. Having everything in its own
section is the 
purpose of the -f*-sections and allows the linker to easily strip them.
I really 
don't get the exception made for .rodata.* here. 

>
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