From bd3d1480a80effbbf3eedf1bd51368730ec9078d Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 6 Apr 2021 10:54:57 +0200 Subject: [PATCH] ld: warn about PE base relocations to sections above .reloc Due to a bogus linker script, or perhaps because a section doesn't get placed by a linker script while default placement puts it too high up, sections can end up above .reloc. Since the process of determining its contents (and hence its size) happens before final section placement, relocations needed for such sections would no longer point at the correct address in the final binary. Warn about this (down the road this may want to become an error, unless size determination and content creation for .reloc would get decoupled). To avoid triggering the warning when .reloc gets discarded, suppress populating the section in the first place in this case. --- ld/ChangeLog | 5 +++++ ld/pe-dll.c | 11 ++++++++++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/ld/ChangeLog b/ld/ChangeLog index d12ba7732c3..71aa06ab45a 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,8 @@ +2021-04-06 Jan Beulich + + * pe-dll.c (generate_reloc): Bail immediately when .reloc is + being discarded. Warn when relocated entry is above .reloc. + 2021-04-05 Alan Modra * configure.ac: Move initfini-array arg handling earlier. Don't diff --git a/ld/pe-dll.c b/ld/pe-dll.c index cdb343bb98b..e7b82ba6ffa 100644 --- a/ld/pe-dll.c +++ b/ld/pe-dll.c @@ -1516,7 +1516,7 @@ generate_reloc (bfd *abfd, struct bfd_link_info *info) bfd *b; struct bfd_section *s; - if (reloc_s == NULL) + if (reloc_s == NULL || reloc_s->output_section == bfd_abs_section_ptr) return; total_relocs = 0; for (b = info->input_bfds; b; b = b->link.next) @@ -1627,6 +1627,15 @@ generate_reloc (bfd *abfd, struct bfd_link_info *info) reloc_data[total_relocs].vma = sec_vma + relocs[i]->address; reloc_data[total_relocs].idx = total_relocs; + /* Since we're only about to determine .reloc's size, + subsequent output section VMA calculations will shift up + sections at this or higher addresses. Relocations for + such sections would hence end up not being correct. */ + if (reloc_data[total_relocs].vma + >= reloc_s->output_section->vma) + einfo (_("%P: base relocation for section `%s' above " + ".reloc section\n"), s->output_section->name); + #define BITS_AND_SHIFT(bits, shift) (bits * 1000 | shift) switch BITS_AND_SHIFT (relocs[i]->howto->bitsize, -- 2.30.2