This improves the portability of the linker script and allows lld to link rom.o
Dot assignment inside an output section has an inconsistent behavior which makes lld difficult to implement. See https://bugs.llvm.org/show_bug.cgi?id=43083
Dropping `. =` turns out to be beneficial to older GNU ld as well because we can delete an ld check detecting "cannot move location counter backwards".
Signed-off-by: Fangrui Song maskray@google.com --- scripts/layoutrom.py | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/scripts/layoutrom.py b/scripts/layoutrom.py index fa270ef..7bc4a57 100755 --- a/scripts/layoutrom.py +++ b/scripts/layoutrom.py @@ -336,14 +336,19 @@ def outRelSections(sections, startsym, useseg=0): if section.finalloc is not None] sections.sort(key=operator.itemgetter(0)) out = "" + location = "_reloc_init_end" for addr, section in sections: loc = section.finalloc if useseg: loc = section.finalsegloc - out += ". = ( 0x%x - %s ) ;\n" % (loc, startsym) + if location == "_reloc_init_end": + out += ". += 0x%x - %s ;\n" % (loc, location) + elif location < loc: + out += ". += 0x%x ;\n" % (loc-location,) if section.name in ('.rodata.str1.1', '.rodata'): out += "_rodata%s = . ;\n" % (section.fileid,) out += "*%s.*(%s)\n" % (section.fileid, section.name) + location = loc + section.size return out
# Build linker script output for a list of relocations.