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| author | Alan Modra <amodra@gmail.com> | 2018-01-26 12:25:09 +1030 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2018-01-26 13:50:09 +1030 |
| commit | ba21f5646454c418e75eb06f6bf1a00a173641ca (patch) | |
| tree | 0b099f14f5a10d32ed71c8b5658de4fa96fdaa77 | |
| parent | 8a69c6d07bd9bd94ce5915fa9d09a2b7e1d163c7 (diff) | |
| download | gdb-ba21f5646454c418e75eb06f6bf1a00a173641ca.zip gdb-ba21f5646454c418e75eb06f6bf1a00a173641ca.tar.gz gdb-ba21f5646454c418e75eb06f6bf1a00a173641ca.tar.bz2 | |
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/ChangeLog | 5 | ||||
| -rw-r--r-- | bfd/elf64-ppc.c | 6 |
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; |