[PATCH v2 4/6] ld: Discard LLVM_ADDRSIG sections.

[Tatsuyuki Ishi]

The symbol indices in addrsig sections requires update in the case of a
partial link, which we currently cannot do. Now that bfd is able to insert
a correct sh_link entry for the addrsig section, this will break the final
linker's heuristic [1] that discards such corrupt section.

As such, strip this section explicitly for ld -r.

[1]: https://github.com/llvm/llvm-project/blob/09c2b7c35af8c4bad39f03e9f60df8bd07323028/lld/ELF/InputFiles.cpp#L540-L554
---
 ld/ldlang.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/ld/ldlang.c b/ld/ldlang.c
index 839535bdb73..ba2d350bbd9 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -2516,6 +2516,13 @@ lang_discard_section_p (asection *section)
       && link_info.resolve_section_groups)
     discard = true;
 
+  /* Discard .llvm_addrsig sections. We don't do the additional processing
+     to keep the symbol indices correct, and when doing a partial link this
+     will end up getting the wrong information to the final linker.  */
+  if (bfd_get_flavour (section->owner) == bfd_target_elf_flavour
+      && elf_section_type (section) == SHT_LLVM_ADDRSIG)
+    discard = true;
+
   /* Discard debugging sections if we are stripping debugging
      information.  */
   if ((link_info.strip == strip_debugger || link_info.strip == strip_all)
-- 
2.36.1