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authorAlan Modra <amodra@gmail.com>2018-01-26 12:25:09 +1030
committerAlan Modra <amodra@gmail.com>2018-01-26 13:50:09 +1030
commitba21f5646454c418e75eb06f6bf1a00a173641ca (patch)
tree0b099f14f5a10d32ed71c8b5658de4fa96fdaa77
parent8a69c6d07bd9bd94ce5915fa9d09a2b7e1d163c7 (diff)
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PowerPC64 .branch_lt size change leads to "stubs don't match calculated size"
https://bugzilla.redhat.com/show_bug.cgi?id=1523457 I haven't analyzed this myself, I'm relying on Nick's excellent analysis. What I believe is happening is that after some number of stub sizing iterations, a long-branch stub needs to be converted to a plt-branch, but either due to stub alignment or other stubs shrinking in size, the stub group section size doesn't change. That means we exit from ppc64_elf_size_stubs after sizing with an incorrect layout, in fact the additional .branch_lt entry overlays .got! Since .TOC. is normally set to .got + 0x8000 the stub sizing code decides that entry is within +/-32k of the TOC pointer and so a three insn stub is sufficient. When we come to build the stubs using a correct non-overlaying layout, a four insn plt-branch stub is generated and the stub group size doesn't match that calculated earlier. * elf64-ppc.c (ppc64_elf_size_stubs): Iterate sizing when .branch_lt changes size.
-rw-r--r--bfd/ChangeLog5
-rw-r--r--bfd/elf64-ppc.c6
2 files changed, 11 insertions, 0 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index ba377ab..4ad0127 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,8 @@
+2018-01-26 Alan Modra <amodra@gmail.com>
+
+ * elf64-ppc.c (ppc64_elf_size_stubs): Iterate sizing when
+ .branch_lt changes size.
+
2018-01-25 Alan Modra <amodra@gmail.com>
PR 22746
diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index b2d288b..5cbb035 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -12702,6 +12702,9 @@ ppc64_elf_size_stubs (struct bfd_link_info *info)
stub_sec->flags &= ~SEC_RELOC;
}
+ if (htab->stub_iteration <= STUB_SHRINK_ITER
+ || htab->brlt->rawsize < htab->brlt->size)
+ htab->brlt->rawsize = htab->brlt->size;
htab->brlt->size = 0;
htab->brlt->reloc_count = 0;
htab->brlt->flags &= ~SEC_RELOC;
@@ -12757,6 +12760,9 @@ ppc64_elf_size_stubs (struct bfd_link_info *info)
break;
if (group == NULL
+ && (htab->brlt->rawsize == htab->brlt->size
+ || (htab->stub_iteration > STUB_SHRINK_ITER
+ && htab->brlt->rawsize > htab->brlt->size))
&& (htab->glink_eh_frame == NULL
|| htab->glink_eh_frame->rawsize == htab->glink_eh_frame->size))
break;