[PATCH] D23352: [ELF] - Linkerscript: implemented simple heuristic for placing orphan sections.

[George Rimar via llvm-commits]

grimar added inline comments.

================
Comment at: ELF/LinkerScript.cpp:283
@@ +282,3 @@
+                        [&](OutputSectionBase<ELFT> *S) {
+                          return getPermissions(S) == getPermissions(OutSec);
+                        });
----------------
silvas wrote:
> I think this also needs to check `&& !(S->getType() & SHT_NOBITS)` so that we don't add a PROGBITS section into BSS.
> 
> E.g. with this patch applied I get this error during a FreeBSD kernel build:
> 
> ```
> BFD: stc5VrZP: section set_pcpu lma 0xffffffff81529d80 overlaps previous sections
> BFD: stc5VrZP: section `set_pcpu' can't be allocated in segment 5
> objcopy: stc5VrZP: Bad value
> BFD: stc5VrZP: section set_pcpu lma 0xffffffff81529d80 overlaps previous sections
> BFD: stc5VrZP: section `set_pcpu' can't be allocated in segment 5
> objcopy: stc5VrZP: Bad value
> *** Error code 1
> ```
> 
> Relevant section of `readelf --sections` output on the binary produced by this patch:
> ```
>   [33] .data             PROGBITS         ffffffff81401000  01015000
>        000000000012823c  0000000000000000  WA       0     0     32
>   [34] .bss              NOBITS           ffffffff81529280  0113d23c
>        0000000000207ad0  0000000000000000  WA       0     0     128
>   [35] set_pcpu          PROGBITS         ffffffff81730d80  0113dd80
>        00000000000010b0  0000000000000000  WA       0     0     128
> ```
Done, thanks !

================
Comment at: ELF/LinkerScript.cpp:303
@@ +302,3 @@
+  ScriptConfig->Commands.emplace(I + 1, Cmd);
+}
+
----------------
ruiu wrote:
> I think I understand what you are trying to do, but still it seems a bit too complicated. Isn't there any way to simplify?
I refactored that. 
Though there are probably not much space to simplify since
I need to insert different things into two different async lists.


https://reviews.llvm.org/D23352