const Elf_Internal_Rela *));
static boolean mips_elf_adjust_dynamic_symbol
PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));
+static boolean mips_elf_always_size_sections
+ PARAMS ((bfd *, struct bfd_link_info *));
static boolean mips_elf_size_dynamic_sections
PARAMS ((bfd *, struct bfd_link_info *));
static boolean mips_elf_finish_dynamic_symbol
line_ptr);
}
\f
+ /* The mips16 compiler uses a couple of special sections to handle
+ floating point arguments.
+
+ Section names that look like .mips16.fn.FNNAME contain stubs that
+ copy floating point arguments from the fp regs to the gp regs and
+ then jump to FNNAME. If any 32 bit function calls FNNAME, the
+ call should be redirected to the stub instead. If no 32 bit
+ function calls FNNAME, the stub should be discarded. We need to
+ consider any reference to the function, not just a call, because
+ if the address of the function is taken we will need the stub,
+ since the address might be passed to a 32 bit function.
+
+ Section names that look like .mips16.call.FNNAME contain stubs
+ that copy floating point arguments from the gp regs to the fp
+ regs and then jump to FNNAME. If FNNAME is a 32 bit function,
+ then any 16 bit function that calls FNNAME should be redirected
+ to the stub instead. If FNNAME is not a 32 bit function, the
+ stub should be discarded.
+
+ .mips16.call.fp.FNNAME sections are similar, but contain stubs
+ which call FNNAME and then copy the return value from the fp regs
+ to the gp regs. These stubs store the return value in $18 while
+ calling FNNAME; any function which might call one of these stubs
+ must arrange to save $18 around the call. (This case is not
+ needed for 32 bit functions that call 16 bit functions, because
+ 16 bit functions always return floating point values in both
+ $f0/$f1 and $2/$3.)
+
+ Note that in all cases FNNAME might be defined statically.
+ Therefore, FNNAME is not used literally. Instead, the relocation
+ information will indicate which symbol the section is for.
+
+ We record any stubs that we find in the symbol table. */
+
+#define FN_STUB ".mips16.fn."
+#define CALL_STUB ".mips16.call."
+#define CALL_FP_STUB ".mips16.call.fp."
+
/* The MIPS ELF linker needs additional information for each symbol in
the global hash table. */
/* Number of MIPS_32 or MIPS_REL32 relocs against this symbol. */
unsigned int mips_32_relocs;
+
+ /* If there is a stub that 32 bit functions should use to call this
+ 16 bit function, this points to the section containing the stub. */
+ asection *fn_stub;
+
+ /* Whether we need the fn_stub; this is set if this symbol appears
+ in any relocs other than a 16 bit call. */
+ boolean need_fn_stub;
+
+ /* If there is a stub that 16 bit functions should use to call this
+ 32 bit function, this points to the section containing the stub. */
+ asection *call_stub;
+
+ /* This is like the call_stub field, but it is used if the function
+ being called returns a floating point value. */
+ asection *call_fp_stub;
};
/* MIPS ELF linker hash table. */
boolean use_rld_obj_head;
/* This is the value of the __rld_map or __rld_obj_head symbol. */
bfd_vma rld_value;
+ /* This is set if we see any mips16 stub sections. */
+ boolean mips16_stubs_seen;
};
/* Look up an entry in a MIPS ELF linker hash table. */
not been set. -1 means there is no associated ifd. */
ret->esym.ifd = -2;
ret->mips_32_relocs = 0;
+ ret->fn_stub = NULL;
+ ret->need_fn_stub = false;
+ ret->call_stub = NULL;
+ ret->call_fp_stub = NULL;
}
return (struct bfd_hash_entry *) ret;
ret->compact_rel_size = 0;
ret->use_rld_obj_head = false;
ret->rld_value = 0;
+ ret->mips16_stubs_seen = false;
return &ret->root.root;
}
struct elf_link_hash_entry *h;
asection *sec;
Elf_Internal_Sym *sym;
+ struct mips_elf_link_hash_entry *mh;
+ int other;
bfd_reloc_status_type r;
r_type = ELF32_R_TYPE (rel->r_info);
}
}
+ mh = (struct mips_elf_link_hash_entry *) h;
+ if (h != NULL)
+ other = h->other;
+ else if (sym != NULL)
+ other = sym->st_other;
+ else
+ other = 0;
+
+ /* If this function has an fn_stub, then it is a mips16
+ function which needs a stub if it is called by a 32 bit
+ function. If this reloc is anything other than a 16 bit
+ call, redirect the reloc to the stub. We don't redirect
+ relocs from other stub functions. */
+ if (r_type != R_MIPS16_26
+ && ((mh != NULL
+ && mh->fn_stub != NULL)
+ || (mh == NULL
+ && elf_tdata (input_bfd)->local_stubs != NULL
+ && elf_tdata (input_bfd)->local_stubs[r_symndx] != NULL))
+ && strncmp (bfd_get_section_name (input_bfd, input_section),
+ FN_STUB, sizeof FN_STUB - 1) != 0
+ && strncmp (bfd_get_section_name (input_bfd, input_section),
+ CALL_STUB, sizeof CALL_STUB - 1) != 0
+ && strncmp (bfd_get_section_name (input_bfd, input_section),
+ CALL_FP_STUB, sizeof CALL_FP_STUB - 1) != 0)
+ {
+ if (mh != NULL)
+ {
+ BFD_ASSERT (mh->need_fn_stub);
+ relocation = (mh->fn_stub->output_section->vma
+ + mh->fn_stub->output_offset);
+ }
+ else
+ {
+ asection *fn_stub;
+
+ fn_stub = elf_tdata (input_bfd)->local_stubs[r_symndx];
+ relocation = (fn_stub->output_section->vma
+ + fn_stub->output_offset);
+ }
+
+ /* RELOCATION now points to 32 bit code. */
+ other = 0;
+ }
+
+ /* If this function has a call_stub, then it is called by a
+ mips16 function; the call needs to go through a stub if
+ this function is a 32 bit function. If this reloc is a
+ 16 bit call, and the symbol is not a 16 bit function,
+ then redirect the reloc to the stub. Note that we don't
+ need to worry about calling the function through a
+ function pointer; such calls are handled by routing
+ through a special mips16 routine. We don't have to check
+ whether this call is from a stub; it can't be, because a
+ stub contains 32 bit code, and hence can not have a 16
+ bit reloc. */
+ if (r_type == R_MIPS16_26
+ && mh != NULL
+ && (mh->call_stub != NULL || mh->call_fp_stub != NULL)
+ && other != STO_MIPS16)
+ {
+ asection *stub;
+
+ /* If both call_stub and call_fp_stub are defined, we
+ can figure out which one to use by seeing which one
+ appears in the input file. */
+ if (mh->call_stub != NULL && mh->call_fp_stub != NULL)
+ {
+ asection *o;
+
+ stub = NULL;
+ for (o = input_bfd->sections; o != NULL; o = o->next)
+ {
+ if (strncmp (bfd_get_section_name (input_bfd, o),
+ CALL_FP_STUB, sizeof CALL_FP_STUB - 1) == 0)
+ {
+ stub = mh->call_fp_stub;
+ break;
+ }
+ }
+ if (stub == NULL)
+ stub = mh->call_stub;
+ }
+ else if (mh->call_stub != NULL)
+ stub = mh->call_stub;
+ else
+ stub = mh->call_fp_stub;
+
+ BFD_ASSERT (stub->_raw_size > 0);
+ relocation = stub->output_section->vma + stub->output_offset;
+ }
+
if (r_type == R_MIPS_HI16)
{
Elf_Internal_Rela *lorel;
addr += 4;
bfd_put_32 (input_bfd, val, contents + addr);
}
- else if (r_type == R_MIPS_26
- && ((h != NULL && h->other == STO_MIPS16)
- || (sym != NULL && sym->st_other == STO_MIPS16)))
+ else if (r_type == R_MIPS_26 && other == STO_MIPS16)
{
unsigned long insn;
| ((insn & 0x3e0) >> 5));
/* If this is a jump to a 32 bit routine, then make
it jalx. */
- if ((h != NULL && h->other != STO_MIPS16)
- || (sym != NULL && sym->st_other != STO_MIPS16))
+ if (other != STO_MIPS16)
insn |= 0x400;
bfd_put_16 (input_bfd, insn, contents + rel->r_offset);
}
asection *sec;
const Elf_Internal_Rela *relocs;
{
+ const char *name;
bfd *dynobj;
Elf_Internal_Shdr *symtab_hdr;
struct elf_link_hash_entry **sym_hashes;
sym_hashes = elf_sym_hashes (abfd);
extsymoff = (elf_bad_symtab (abfd)) ? 0 : symtab_hdr->sh_info;
+ /* Check for the mips16 stub sections. */
+
+ name = bfd_get_section_name (abfd, sec);
+ if (strncmp (name, FN_STUB, sizeof FN_STUB - 1) == 0)
+ {
+ unsigned long r_symndx;
+
+ /* Look at the relocation information to figure out which symbol
+ this is for. */
+
+ r_symndx = ELF32_R_SYM (relocs->r_info);
+
+ if (r_symndx < extsymoff
+ || sym_hashes[r_symndx - extsymoff] == NULL)
+ {
+ asection *o;
+
+ /* This stub is for a local symbol. This stub will only be
+ needed if there is some relocation in this BFD, other
+ than a 16 bit function call, which refers to this symbol. */
+ for (o = abfd->sections; o != NULL; o = o->next)
+ {
+ Elf_Internal_Rela *sec_relocs;
+ const Elf_Internal_Rela *r, *rend;
+
+ /* We can ignore stub sections when looking for relocs. */
+ if ((o->flags & SEC_RELOC) == 0
+ || o->reloc_count == 0
+ || strncmp (bfd_get_section_name (abfd, o), FN_STUB,
+ sizeof FN_STUB - 1) == 0
+ || strncmp (bfd_get_section_name (abfd, o), CALL_STUB,
+ sizeof CALL_STUB - 1) == 0
+ || strncmp (bfd_get_section_name (abfd, o), CALL_FP_STUB,
+ sizeof CALL_FP_STUB - 1) == 0)
+ continue;
+
+ sec_relocs = (_bfd_elf32_link_read_relocs
+ (abfd, o, (PTR) NULL,
+ (Elf_Internal_Rela *) NULL,
+ info->keep_memory));
+ if (sec_relocs == NULL)
+ return false;
+
+ rend = sec_relocs + o->reloc_count;
+ for (r = sec_relocs; r < rend; r++)
+ if (ELF32_R_SYM (r->r_info) == r_symndx
+ && ELF32_R_TYPE (r->r_info) != R_MIPS16_26)
+ break;
+
+ if (! info->keep_memory)
+ free (sec_relocs);
+
+ if (r < rend)
+ break;
+ }
+
+ if (o == NULL)
+ {
+ /* There is no non-call reloc for this stub, so we do
+ not need it. Since this function is called before
+ the linker maps input sections to output sections, we
+ can easily discard it by setting the SEC_EXCLUDE
+ flag. */
+ sec->flags |= SEC_EXCLUDE;
+ return true;
+ }
+
+ /* Record this stub in an array of local symbol stubs for
+ this BFD. */
+ if (elf_tdata (abfd)->local_stubs == NULL)
+ {
+ unsigned long symcount;
+ asection **n;
+
+ if (elf_bad_symtab (abfd))
+ symcount = symtab_hdr->sh_size / sizeof (Elf32_External_Sym);
+ else
+ symcount = symtab_hdr->sh_info;
+ n = (asection **) bfd_zalloc (abfd,
+ symcount * sizeof (asection *));
+ if (n == NULL)
+ return false;
+ elf_tdata (abfd)->local_stubs = n;
+ }
+
+ elf_tdata (abfd)->local_stubs[r_symndx] = sec;
+
+ /* We don't need to set mips16_stubs_seen in this case.
+ That flag is used to see whether we need to look through
+ the global symbol table for stubs. We don't need to set
+ it here, because we just have a local stub. */
+ }
+ else
+ {
+ struct mips_elf_link_hash_entry *h;
+
+ h = ((struct mips_elf_link_hash_entry *)
+ sym_hashes[r_symndx - extsymoff]);
+
+ /* H is the symbol this stub is for. */
+
+ h->fn_stub = sec;
+ mips_elf_hash_table (info)->mips16_stubs_seen = true;
+ }
+ }
+ else if (strncmp (name, CALL_STUB, sizeof CALL_STUB - 1) == 0
+ || strncmp (name, CALL_FP_STUB, sizeof CALL_FP_STUB - 1) == 0)
+ {
+ unsigned long r_symndx;
+ struct mips_elf_link_hash_entry *h;
+ asection **loc;
+
+ /* Look at the relocation information to figure out which symbol
+ this is for. */
+
+ r_symndx = ELF32_R_SYM (relocs->r_info);
+
+ if (r_symndx < extsymoff
+ || sym_hashes[r_symndx - extsymoff] == NULL)
+ {
+ /* This stub was actually built for a static symbol defined
+ in the same file. We assume that all static symbols in
+ mips16 code are themselves mips16, so we can simply
+ discard this stub. Since this function is called before
+ the linker maps input sections to output sections, we can
+ easily discard it by setting the SEC_EXCLUDE flag. */
+ sec->flags |= SEC_EXCLUDE;
+ return true;
+ }
+
+ h = ((struct mips_elf_link_hash_entry *)
+ sym_hashes[r_symndx - extsymoff]);
+
+ /* H is the symbol this stub is for. */
+
+ if (strncmp (name, CALL_FP_STUB, sizeof CALL_FP_STUB - 1) == 0)
+ loc = &h->call_fp_stub;
+ else
+ loc = &h->call_stub;
+
+ /* If we already have an appropriate stub for this function, we
+ don't need another one, so we can discard this one. Since
+ this function is called before the linker maps input sections
+ to output sections, we can easily discard it by setting the
+ SEC_EXCLUDE flag. We can also discard this section if we
+ happen to already know that this is a mips16 function; it is
+ not necessary to check this here, as it is checked later, but
+ it is slightly faster to check now. */
+ if (*loc != NULL || h->root.other == STO_MIPS16)
+ {
+ sec->flags |= SEC_EXCLUDE;
+ return true;
+ }
+
+ *loc = sec;
+ mips_elf_hash_table (info)->mips16_stubs_seen = true;
+ }
+
if (dynobj == NULL)
{
sgot = NULL;
default:
break;
}
+
+ /* If this reloc is not a 16 bit call, and it has a global
+ symbol, then we will need the fn_stub if there is one.
+ References from a stub section do not count. */
+ if (h != NULL
+ && ELF32_R_TYPE (rel->r_info) != R_MIPS16_26
+ && strncmp (bfd_get_section_name (abfd, sec), FN_STUB,
+ sizeof FN_STUB - 1) != 0
+ && strncmp (bfd_get_section_name (abfd, sec), CALL_STUB,
+ sizeof CALL_STUB - 1) != 0
+ && strncmp (bfd_get_section_name (abfd, sec), CALL_FP_STUB,
+ sizeof CALL_FP_STUB - 1) != 0)
+ {
+ struct mips_elf_link_hash_entry *mh;
+
+ mh = (struct mips_elf_link_hash_entry *) h;
+ mh->need_fn_stub = true;
+ }
}
return true;
return true;
}
+/* This function is called after all the input files have been read,
+ and the input sections have been assigned to output sections. We
+ check for any mips16 stub sections that we can discard. */
+
+static boolean mips_elf_check_mips16_stubs
+ PARAMS ((struct mips_elf_link_hash_entry *, PTR));
+
+static boolean
+mips_elf_always_size_sections (output_bfd, info)
+ bfd *output_bfd;
+ struct bfd_link_info *info;
+{
+ if (info->relocateable
+ || ! mips_elf_hash_table (info)->mips16_stubs_seen)
+ return true;
+
+ mips_elf_link_hash_traverse (mips_elf_hash_table (info),
+ mips_elf_check_mips16_stubs,
+ (PTR) NULL);
+
+ return true;
+}
+
+/* Check the mips16 stubs for a particular symbol, and see if we can
+ discard them. */
+
+/*ARGSUSED*/
+static boolean
+mips_elf_check_mips16_stubs (h, data)
+ struct mips_elf_link_hash_entry *h;
+ PTR data;
+{
+ if (h->fn_stub != NULL
+ && ! h->need_fn_stub)
+ {
+ /* We don't need the fn_stub; the only references to this symbol
+ are 16 bit calls. Clobber the size to 0 to prevent it from
+ being included in the link. */
+ h->fn_stub->_raw_size = 0;
+ h->fn_stub->_cooked_size = 0;
+ h->fn_stub->flags &= ~ SEC_RELOC;
+ h->fn_stub->reloc_count = 0;
+ h->fn_stub->flags |= SEC_EXCLUDE;
+ }
+
+ if (h->call_stub != NULL
+ && h->root.other == STO_MIPS16)
+ {
+ /* We don't need the call_stub; this is a 16 bit function, so
+ calls from other 16 bit functions are OK. Clobber the size
+ to 0 to prevent it from being included in the link. */
+ h->call_stub->_raw_size = 0;
+ h->call_stub->_cooked_size = 0;
+ h->call_stub->flags &= ~ SEC_RELOC;
+ h->call_stub->reloc_count = 0;
+ h->call_stub->flags |= SEC_EXCLUDE;
+ }
+
+ if (h->call_fp_stub != NULL
+ && h->root.other == STO_MIPS16)
+ {
+ /* We don't need the call_stub; this is a 16 bit function, so
+ calls from other 16 bit functions are OK. Clobber the size
+ to 0 to prevent it from being included in the link. */
+ h->call_fp_stub->_raw_size = 0;
+ h->call_fp_stub->_cooked_size = 0;
+ h->call_fp_stub->flags &= ~ SEC_RELOC;
+ h->call_fp_stub->reloc_count = 0;
+ h->call_fp_stub->flags |= SEC_EXCLUDE;
+ }
+
+ return true;
+}
+
/* Set the sizes of the dynamic sections. */
static boolean
#define elf_backend_check_relocs mips_elf_check_relocs
#define elf_backend_adjust_dynamic_symbol \
mips_elf_adjust_dynamic_symbol
+#define elf_backend_always_size_sections \
+ mips_elf_always_size_sections
#define elf_backend_size_dynamic_sections \
mips_elf_size_dynamic_sections
#define elf_backend_relocate_section mips_elf_relocate_section
projects / deliverable / binutils-gdb.git / commitdiff
