#define mips_elf_section_data(sec) \
((struct _mips_elf_section_data *) elf_section_data (sec))
+/* The ABI says that every symbol used by dynamic relocations must have
+ a global GOT entry. Among other things, this provides the dynamic
+ linker with a free, directly-indexed cache. The GOT can therefore
+ contain symbols that are not referenced by GOT relocations themselves
+ (in other words, it may have symbols that are not referenced by things
+ like R_MIPS_GOT16 and R_MIPS_GOT_PAGE).
+
+ GOT relocations are less likely to overflow if we put the associated
+ GOT entries towards the beginning. We therefore divide the global
+ GOT entries into two areas: "normal" and "reloc-only". Entries in
+ the first area can be used for both dynamic relocations and GP-relative
+ accesses, while those in the "reloc-only" area are for dynamic
+ relocations only.
+
+ These GGA_* ("Global GOT Area") values are organised so that lower
+ values are more general than higher values. Also, non-GGA_NONE
+ values are ordered by the position of the area in the GOT. */
+#define GGA_NORMAL 0
+#define GGA_RELOC_ONLY 1
+#define GGA_NONE 2
+
/* This structure is passed to mips_elf_sort_hash_table_f when sorting
the dynamic symbols. */
overloaded already. */
bfd_vma tls_got_offset;
+ /* The highest GGA_* value that satisfies all references to this symbol. */
+ unsigned int global_got_area : 2;
+
/* True if one of the relocations described by possibly_dynamic_relocs
is against a readonly section. */
unsigned int readonly_reloc : 1;
ret->call_stub = NULL;
ret->call_fp_stub = NULL;
ret->tls_type = GOT_NORMAL;
+ ret->global_got_area = GGA_NONE;
ret->readonly_reloc = FALSE;
ret->no_fn_stub = FALSE;
ret->need_fn_stub = FALSE;
if (h->root.dynindx == -1)
return TRUE;
- /* Global symbols that need GOT entries that are not explicitly
- referenced are marked with got offset 2. Those that are
- referenced get a 1, and those that don't need GOT entries get
- -1. Forced local symbols may also be marked with got offset 1,
- but are never given global GOT entries. */
- if (h->root.got.offset == 2)
+ switch (h->global_got_area)
{
- BFD_ASSERT (h->tls_type == GOT_NORMAL);
+ case GGA_NONE:
+ h->root.dynindx = hsd->max_non_got_dynindx++;
+ break;
- if (hsd->max_unref_got_dynindx == hsd->min_got_dynindx)
- hsd->low = (struct elf_link_hash_entry *) h;
- h->root.dynindx = hsd->max_unref_got_dynindx++;
- }
- else if (h->root.got.offset != 1 || h->root.forced_local)
- h->root.dynindx = hsd->max_non_got_dynindx++;
- else
- {
+ case GGA_NORMAL:
BFD_ASSERT (h->tls_type == GOT_NORMAL);
h->root.dynindx = --hsd->min_got_dynindx;
hsd->low = (struct elf_link_hash_entry *) h;
+ break;
+
+ case GGA_RELOC_ONLY:
+ BFD_ASSERT (h->tls_type == GOT_NORMAL);
+
+ if (hsd->max_unref_got_dynindx == hsd->min_got_dynindx)
+ hsd->low = (struct elf_link_hash_entry *) h;
+ h->root.dynindx = hsd->max_unref_got_dynindx++;
+ break;
}
return TRUE;
unsigned char tls_flag)
{
struct mips_elf_link_hash_table *htab;
+ struct mips_elf_link_hash_entry *hmips;
struct mips_got_entry entry, **loc;
struct mips_got_info *g;
htab = mips_elf_hash_table (info);
+ hmips = (struct mips_elf_link_hash_entry *) h;
/* A global symbol in the GOT must also be in the dynamic symbol
table. */
memcpy (*loc, &entry, sizeof entry);
- if (h->got.offset != MINUS_ONE)
- return TRUE;
-
if (tls_flag == 0)
- /* By setting this to a value other than -1, we are indicating that
- there needs to be a GOT entry for H. Avoid using zero, as the
- generic ELF copy_indirect_symbol tests for <= 0. */
- h->got.offset = 1;
+ hmips->global_got_area = GGA_NORMAL;
return TRUE;
}
h = entry->d.h;
while (h->root.root.type == bfd_link_hash_indirect
|| h->root.root.type == bfd_link_hash_warning)
- h = (struct mips_elf_link_hash_entry *) h->root.root.u.i.link;
+ {
+ BFD_ASSERT (h->global_got_area == GGA_NONE);
+ h = (struct mips_elf_link_hash_entry *) h->root.root.u.i.link;
+ }
entry->d.h = h;
}
slot = htab_find_slot (*new_got, entry, INSERT);
return TRUE;
}
-/* An elf_link_hash_traverse callback for which DATA points to a mips_got_info.
- Add each forced-local GOT symbol to DATA's local_gotno field. */
+/* A mips_elf_link_hash_traverse callback for which DATA points
+ to a mips_got_info. Add each forced-local GOT symbol to DATA's
+ local_gotno field. */
static int
-mips_elf_count_forced_local_got_symbols (struct elf_link_hash_entry *h,
+mips_elf_count_forced_local_got_symbols (struct mips_elf_link_hash_entry *h,
void *data)
{
struct mips_got_info *g;
g = (struct mips_got_info *) data;
- if (h->got.offset != MINUS_ONE
- && (h->forced_local || h->dynindx == -1))
+ if (h->global_got_area != GGA_NONE
+ && (h->root.forced_local || h->root.dynindx == -1))
{
/* We no longer need this entry if it was only used for
relocations; those relocations will be against the
null or section symbol instead of H. */
- if (h->got.offset == 2)
- h->got.offset = MINUS_ONE;
- else
+ if (h->global_got_area != GGA_RELOC_ONLY)
g->local_gotno++;
+ h->global_got_area = GGA_NONE;
}
return 1;
}
mips_tls_got_relocs (arg->info, entry->tls_type,
entry->symndx == -1 ? &entry->d.h->root : NULL);
- if (entry->abfd != NULL && entry->symndx == -1
- && entry->d.h->root.dynindx != -1
- && !entry->d.h->root.forced_local
- && entry->d.h->tls_type == GOT_NORMAL)
+ if (entry->abfd != NULL
+ && entry->symndx == -1
+ && entry->d.h->global_got_area != GGA_NONE)
{
if (g)
{
++arg->needed_relocs;
}
else
- entry->d.h->root.got.offset = arg->value;
+ entry->d.h->global_got_area = arg->value;
}
return 1;
*bfdgotp = bfdgot;
}
- /* The IRIX dynamic linker requires every symbol that is referenced
- in a dynamic relocation to be present in the primary GOT, so
- arrange for them to appear after those that are actually
- referenced.
-
- GNU/Linux could very well do without it, but it would slow down
- the dynamic linker, since it would have to resolve every dynamic
- symbol referenced in other GOTs more than once, without help from
- the cache. Also, knowing that every external symbol has a GOT
- helps speed up the resolution of local symbols too, so GNU/Linux
- follows IRIX's practice.
-
- The number 2 is used by mips_elf_sort_hash_table_f to count
- global GOT symbols that are unreferenced in the primary GOT, with
- an initial dynamic index computed from gg->assigned_gotno, where
- the number of unreferenced global entries in the primary GOT is
- preserved. */
- if (1)
- {
- gg->assigned_gotno = gg->global_gotno - g->global_gotno;
- g->global_gotno = gg->global_gotno;
- set_got_offset_arg.value = 2;
- }
- else
- {
- /* This could be used for dynamic linkers that don't optimize
- symbol resolution while applying relocations so as to use
- primary GOT entries or assuming the symbol is locally-defined.
- With this code, we assign lower dynamic indices to global
- symbols that are not referenced in the primary GOT, so that
- their entries can be omitted. */
- gg->assigned_gotno = 0;
- set_got_offset_arg.value = -1;
- }
+ /* Every symbol that is referenced in a dynamic relocation must be
+ present in the primary GOT, so arrange for them to appear after
+ those that are actually referenced. */
+ gg->assigned_gotno = gg->global_gotno - g->global_gotno;
+ g->global_gotno = gg->global_gotno;
- /* Reorder dynamic symbols as described above (which behavior
- depends on the setting of VALUE). */
set_got_offset_arg.g = NULL;
+ set_got_offset_arg.value = GGA_RELOC_ONLY;
htab_traverse (gg->got_entries, mips_elf_set_global_got_offset,
&set_got_offset_arg);
- set_got_offset_arg.value = 1;
+ set_got_offset_arg.value = GGA_NORMAL;
htab_traverse (g->got_entries, mips_elf_set_global_got_offset,
&set_got_offset_arg);
if (! mips_elf_sort_hash_table (info, 1))
return FALSE;
/* Count the number of forced-local entries. */
- elf_link_hash_traverse (elf_hash_table (info),
- mips_elf_count_forced_local_got_symbols, g);
+ mips_elf_link_hash_traverse (htab,
+ mips_elf_count_forced_local_got_symbols, g);
/* There has to be a global GOT entry for every symbol with
a dynamic symbol table index of DT_MIPS_GOTSYM or
dirmips->readonly_reloc = TRUE;
if (indmips->no_fn_stub)
dirmips->no_fn_stub = TRUE;
+ if (indmips->global_got_area < dirmips->global_got_area)
+ dirmips->global_got_area = indmips->global_got_area;
+ if (indmips->global_got_area < GGA_NONE)
+ indmips->global_got_area = GGA_NONE;
if (dirmips->tls_type == 0)
dirmips->tls_type = indmips->tls_type;
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