[PATCH] Make rom16.o linkable with lld

[Fangrui Song]

(1) In romlayout.S, .fixedaddr.\addr sections do have not the SHF_ALLOC flag.
It does not make sense to reference a SHF_ALLOC section from a non-SHF_ALLOC section via R_386_PC16.
GNU ld allows it but lld will warn. Add the SHF_ALLOC flag.

(2) lld requires output section descriptions to be sorted by address.

Signed-off-by: Fangrui Song

(Note: with
https://mail.coreboot.org/hyperkitty/list/[e-mail]/thread/CJR7WU6...
and this patch, qemu-system-x86_64 -boot menu=on,splash-time=15000 -bios out/bios.bin -nographic
seems to work for me with a small change to lld (allow ET_EXEC to used
as if a relocatable object)

More precisely, during:
ld.lld -N -T out/romlayout32flat.lds out/rom16.strip.o out/rom32seg.strip.o out/code32flat.o -o out/rom.o

out/rom16.strip.o and out/rom32seg.strip.o are ET_EXEC, instead of ET_REL. lld<11 will reject such input.
)

---
 scripts/layoutrom.py | 4 ++++
 src/romlayout.S      | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/scripts/layoutrom.py b/scripts/layoutrom.py
index bbf07aa..14e6ada 100755
--- a/scripts/layoutrom.py
+++ b/scripts/layoutrom.py
@@ -321,6 +321,10 @@ def outXRefs(sections, useseg=0, exportsyms=[], forcedelta=0):

# Write LD script includes for the given sections
 def outSections(sections, useseg=0):
+    if useseg:
+        sections.sort(key=lambda x: x.finalsegloc)
+    else:
+        sections.sort(key=lambda x: x.finalloc)
     out = ""
     for section in sections:
         loc = section.finalloc
diff --git a/src/romlayout.S b/src/romlayout.S
index c4a4635..a854783 100644
--- a/src/romlayout.S
+++ b/src/romlayout.S
@@ -587,7 +587,7 @@ entry_18:

// Specify a location in the fixed part of bios area.
         .macro ORG addr
-        .section .fixedaddr.\addr
+        .section .fixedaddr.\addr,"a"
         .endm

ORG 0xe05b