PowerPC64 --emit-relocs support for notoc stubs
Alan Modra
amodra@gmail.com
Fri Aug 31 15:46:00 GMT 2018
This patch uses the newly defined high-part REL16 relocs to emit
relocations on the notoc stubs as we already do for other stubs.
* elf64-ppc.c (num_relocs_for_offset): New function.
(emit_relocs_for_offset): New function.
(use_global_in_relocs): New function, split out from..
(ppc_build_one_stub): ..here. Output relocations for notoc stubs.
(ppc_size_one_stub): Calculate reloc count for notoc stubs.
(ppc64_elf_size_stubs): Don't count undefined syms in stub_globals.
diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 5826c2288a..eadde17615 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -9626,6 +9626,86 @@ size_offset (bfd_vma off)
return size + 16;
}
+static unsigned int
+num_relocs_for_offset (bfd_vma off)
+{
+ unsigned int num_rel;
+ if (off + 0x8000 < 0x10000)
+ num_rel = 1;
+ else if (off + 0x80008000ULL < 0x100000000ULL)
+ num_rel = 2;
+ else
+ {
+ num_rel = 1;
+ if (off + 0x800000000000ULL >= 0x1000000000000ULL
+ && ((off >> 32) & 0xffff) != 0)
+ num_rel += 1;
+ if (PPC_HI (off) != 0)
+ num_rel += 1;
+ if (PPC_LO (off) != 0)
+ num_rel += 1;
+ }
+ return num_rel;
+}
+
+static Elf_Internal_Rela *
+emit_relocs_for_offset (struct bfd_link_info *info, Elf_Internal_Rela *r,
+ bfd_vma roff, bfd_vma targ, bfd_vma off)
+{
+ bfd_vma relative_targ = targ - (roff - 8);
+ if (bfd_big_endian (info->output_bfd))
+ roff += 2;
+ r->r_offset = roff;
+ r->r_addend = relative_targ + roff;
+ if (off + 0x8000 < 0x10000)
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL16);
+ else if (off + 0x80008000ULL < 0x100000000ULL)
+ {
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_HA);
+ ++r;
+ roff += 4;
+ r->r_offset = roff;
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_LO);
+ r->r_addend = relative_targ + roff;
+ }
+ else
+ {
+ if (off + 0x800000000000ULL < 0x1000000000000ULL)
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_HIGHER);
+ else
+ {
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_HIGHEST);
+ if (((off >> 32) & 0xffff) != 0)
+ {
+ ++r;
+ roff += 4;
+ r->r_offset = roff;
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_HIGHER);
+ r->r_addend = relative_targ + roff;
+ }
+ }
+ if (((off >> 32) & 0xffffffffULL) != 0)
+ roff += 4;
+ if (PPC_HI (off) != 0)
+ {
+ ++r;
+ roff += 4;
+ r->r_offset = roff;
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_HIGH);
+ r->r_addend = relative_targ + roff;
+ }
+ if (PPC_LO (off) != 0)
+ {
+ ++r;
+ roff += 4;
+ r->r_offset = roff;
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_LO);
+ r->r_addend = relative_targ + roff;
+ }
+ }
+ return r;
+}
+
/* Emit .eh_frame opcode to advance pc by DELTA. */
static bfd_byte *
@@ -10049,6 +10129,65 @@ get_relocs (asection *sec, int count)
return relocs;
}
+/* Convert the relocs R[0] thru R[-NUM_REL+1], which are all no-symbol
+ forms, to the equivalent relocs against the global symbol given by
+ STUB_ENTRY->H. */
+
+static bfd_boolean
+use_global_in_relocs (struct ppc_link_hash_table *htab,
+ struct ppc_stub_hash_entry *stub_entry,
+ Elf_Internal_Rela *r, unsigned int num_rel)
+{
+ struct elf_link_hash_entry **hashes;
+ unsigned long symndx;
+ struct ppc_link_hash_entry *h;
+ bfd_vma symval;
+
+ /* Relocs are always against symbols in their own object file. Fake
+ up global sym hashes for the stub bfd (which has no symbols). */
+ hashes = elf_sym_hashes (htab->params->stub_bfd);
+ if (hashes == NULL)
+ {
+ bfd_size_type hsize;
+
+ /* When called the first time, stub_globals will contain the
+ total number of symbols seen during stub sizing. After
+ allocating, stub_globals is used as an index to fill the
+ hashes array. */
+ hsize = (htab->stub_globals + 1) * sizeof (*hashes);
+ hashes = bfd_zalloc (htab->params->stub_bfd, hsize);
+ if (hashes == NULL)
+ return FALSE;
+ elf_sym_hashes (htab->params->stub_bfd) = hashes;
+ htab->stub_globals = 1;
+ }
+ symndx = htab->stub_globals++;
+ h = stub_entry->h;
+ hashes[symndx] = &h->elf;
+ if (h->oh != NULL && h->oh->is_func)
+ h = ppc_follow_link (h->oh);
+ BFD_ASSERT (h->elf.root.type == bfd_link_hash_defined
+ || h->elf.root.type == bfd_link_hash_defweak);
+ symval = (h->elf.root.u.def.value
+ + h->elf.root.u.def.section->output_offset
+ + h->elf.root.u.def.section->output_section->vma);
+ while (num_rel-- != 0)
+ {
+ r->r_info = ELF64_R_INFO (symndx, ELF64_R_TYPE (r->r_info));
+ if (h->elf.root.u.def.section != stub_entry->target_section)
+ {
+ /* H is an opd symbol. The addend must be zero, and the
+ branch reloc is the only one we can convert. */
+ r->r_addend = 0;
+ break;
+ }
+ else
+ r->r_addend -= symval;
+ --r;
+ }
+ return TRUE;
+}
+
static bfd_vma
get_r2off (struct bfd_link_info *info,
struct ppc_stub_hash_entry *stub_entry)
@@ -10092,10 +10231,11 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
struct bfd_link_info *info;
struct ppc_link_hash_table *htab;
bfd_byte *loc;
- bfd_byte *p;
+ bfd_byte *p, *relp;
bfd_vma targ, off;
Elf_Internal_Rela *r;
asection *plt;
+ int num_rel;
/* Massage our args to the form they really have. */
stub_entry = (struct ppc_stub_hash_entry *) gen_entry;
@@ -10171,41 +10311,9 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
r->r_offset = p - 4 - stub_entry->group->stub_sec->contents;
r->r_info = ELF64_R_INFO (0, R_PPC64_REL24);
r->r_addend = targ;
- if (stub_entry->h != NULL)
- {
- struct elf_link_hash_entry **hashes;
- unsigned long symndx;
- struct ppc_link_hash_entry *h;
-
- hashes = elf_sym_hashes (htab->params->stub_bfd);
- if (hashes == NULL)
- {
- bfd_size_type hsize;
-
- hsize = (htab->stub_globals + 1) * sizeof (*hashes);
- hashes = bfd_zalloc (htab->params->stub_bfd, hsize);
- if (hashes == NULL)
- return FALSE;
- elf_sym_hashes (htab->params->stub_bfd) = hashes;
- htab->stub_globals = 1;
- }
- symndx = htab->stub_globals++;
- h = stub_entry->h;
- hashes[symndx] = &h->elf;
- r->r_info = ELF64_R_INFO (symndx, R_PPC64_REL24);
- if (h->oh != NULL && h->oh->is_func)
- h = ppc_follow_link (h->oh);
- if (h->elf.root.u.def.section != stub_entry->target_section)
- /* H is an opd symbol. The addend must be zero. */
- r->r_addend = 0;
- else
- {
- off = (h->elf.root.u.def.value
- + h->elf.root.u.def.section->output_offset
- + h->elf.root.u.def.section->output_section->vma);
- r->r_addend -= off;
- }
- }
+ if (stub_entry->h != NULL
+ && !use_global_in_relocs (htab, stub_entry, r, 1))
+ return FALSE;
}
break;
@@ -10408,6 +10516,8 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
+ stub_entry->target_section->output_section->vma);
off = targ - off;
+ relp = p;
+ num_rel = 0;
/* The notoc stubs calculate their target (either a PLT entry or
the global entry point of a function) relative to the PC
returned by the "bcl" two instructions past the start of the
@@ -10419,6 +10529,7 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
if (stub_entry->stub_type <= ppc_stub_long_branch_both)
{
bfd_vma from;
+ num_rel = 1;
from = (stub_entry->stub_offset
+ stub_entry->group->stub_sec->output_offset
+ stub_entry->group->stub_sec->output_section->vma
@@ -10434,6 +10545,29 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
}
p += 4;
+ if (info->emitrelocations)
+ {
+ bfd_vma roff;
+ num_rel += num_relocs_for_offset (off);
+ r = get_relocs (stub_entry->group->stub_sec, num_rel);
+ if (r == NULL)
+ return FALSE;
+ roff = relp + 16 - stub_entry->group->stub_sec->contents;
+ r = emit_relocs_for_offset (info, r, roff, targ, off);
+ if (stub_entry->stub_type == ppc_stub_long_branch_notoc
+ || stub_entry->stub_type == ppc_stub_long_branch_both)
+ {
+ ++r;
+ roff = p - 4 - stub_entry->group->stub_sec->contents;
+ r->r_offset = roff;
+ r->r_info = ELF64_R_INFO (0, R_PPC64_REL24);
+ r->r_addend = targ;
+ if (stub_entry->h != NULL
+ && !use_global_in_relocs (htab, stub_entry, r, num_rel))
+ return FALSE;
+ }
+ }
+
if (htab->glink_eh_frame != NULL
&& htab->glink_eh_frame->size != 0)
{
@@ -10759,6 +10893,13 @@ ppc_size_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
+ stub_entry->target_section->output_section->vma);
off = targ - off;
+ if (info->emitrelocations)
+ {
+ stub_entry->group->stub_sec->reloc_count
+ += num_relocs_for_offset (off);
+ stub_entry->group->stub_sec->flags |= SEC_RELOC;
+ }
+
extra = size_offset (off - 8);
/* Include branch insn plus those in the offset sequence. */
size += 4 + extra;
@@ -10786,6 +10927,8 @@ ppc_size_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
- ppc_stub_long_branch_notoc);
size += 4;
}
+ else if (info->emitrelocations)
+ stub_entry->group->stub_sec->reloc_count +=1;
break;
case ppc_stub_plt_call_notoc:
@@ -10821,6 +10964,13 @@ ppc_size_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
off -= pad;
}
+ if (info->emitrelocations)
+ {
+ stub_entry->group->stub_sec->reloc_count
+ += num_relocs_for_offset (off - 8);
+ stub_entry->group->stub_sec->flags |= SEC_RELOC;
+ }
+
size = plt_stub_size (htab, stub_entry, off);
/* After the bcl, lr has been modified so we need to emit
@@ -12184,7 +12334,9 @@ ppc64_elf_size_stubs (struct bfd_link_info *info)
= hash ? hash->elf.type : ELF_ST_TYPE (sym->st_info);
stub_entry->other = hash ? hash->elf.other : sym->st_other;
- if (stub_entry->h != NULL)
+ if (hash != NULL
+ && (hash->elf.root.type == bfd_link_hash_defined
+ || hash->elf.root.type == bfd_link_hash_defweak))
htab->stub_globals += 1;
}
--
Alan Modra
Australia Development Lab, IBM
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