return false;
}
+ // Whether we have an NOP instruction. If not, use mov r0, r0 instead.
+ bool
+ may_use_arm_nop() const
+ {
+ // FIXME: This should not hard-coded.
+ return false;
+ }
+
// Process the relocations to determine unreferenced sections for
// garbage collection.
void
return val;
}
- // FIXME: This probably only works for Android on ARM v5te. We should
- // following GNU ld for the general case.
- template<unsigned r_type>
- static inline typename This::Status
- arm_branch_common(unsigned char *view,
- const Sized_relobj<32, big_endian>* object,
- const Symbol_value<32>* psymval,
- Arm_address address,
- Arm_address thumb_bit)
- {
- typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype;
- Valtype* wv = reinterpret_cast<Valtype*>(view);
- Valtype val = elfcpp::Swap<32, big_endian>::readval(wv);
-
- bool insn_is_b = (((val >> 28) & 0xf) <= 0xe)
- && ((val & 0x0f000000UL) == 0x0a000000UL);
- bool insn_is_uncond_bl = (val & 0xff000000UL) == 0xeb000000UL;
- bool insn_is_cond_bl = (((val >> 28) & 0xf) < 0xe)
- && ((val & 0x0f000000UL) == 0x0b000000UL);
- bool insn_is_blx = (val & 0xfe000000UL) == 0xfa000000UL;
- bool insn_is_any_branch = (val & 0x0e000000UL) == 0x0a000000UL;
-
- if (r_type == elfcpp::R_ARM_CALL)
- {
- if (!insn_is_uncond_bl && !insn_is_blx)
- return This::STATUS_BAD_RELOC;
- }
- else if (r_type == elfcpp::R_ARM_JUMP24)
- {
- if (!insn_is_b && !insn_is_cond_bl)
- return This::STATUS_BAD_RELOC;
- }
- else if (r_type == elfcpp::R_ARM_PLT32)
- {
- if (!insn_is_any_branch)
- return This::STATUS_BAD_RELOC;
- }
- else
- gold_unreachable();
-
- Valtype addend = utils::sign_extend<26>(val << 2);
- Valtype x = (psymval->value(object, addend) | thumb_bit) - address;
-
- // If target has thumb bit set, we need to either turn the BL
- // into a BLX (for ARMv5 or above) or generate a stub.
- if (x & 1)
- {
- // Turn BL to BLX.
- if (insn_is_uncond_bl)
- val = (val & 0xffffff) | 0xfa000000 | ((x & 2) << 23);
- else
- return This::STATUS_BAD_RELOC;
- }
- else
- gold_assert(!insn_is_blx);
-
- val = utils::bit_select(val, (x >> 2), 0xffffffUL);
- elfcpp::Swap<32, big_endian>::writeval(wv, val);
- return (utils::has_overflow<26>(x)
- ? This::STATUS_OVERFLOW : This::STATUS_OKAY);
- }
+ // Handle ARM long branches.
+ static typename This::Status
+ arm_branch_common(unsigned int, const Relocate_info<32, big_endian>*,
+ unsigned char *, const Sized_symbol<32>*,
+ const Arm_relobj<big_endian>*, unsigned int,
+ const Symbol_value<32>*, Arm_address, Arm_address, bool);
public:
// R_ARM_PLT32: (S + A) | T - P
static inline typename This::Status
- plt32(unsigned char *view,
- const Sized_relobj<32, big_endian>* object,
+ plt32(const Relocate_info<32, big_endian>* relinfo,
+ unsigned char *view,
+ const Sized_symbol<32>* gsym,
+ const Arm_relobj<big_endian>* object,
+ unsigned int r_sym,
const Symbol_value<32>* psymval,
Arm_address address,
- Arm_address thumb_bit)
+ Arm_address thumb_bit,
+ bool is_weakly_undefined_without_plt)
{
- return arm_branch_common<elfcpp::R_ARM_PLT32>(view, object, psymval,
- address, thumb_bit);
+ return arm_branch_common(elfcpp::R_ARM_PLT32, relinfo, view, gsym,
+ object, r_sym, psymval, address, thumb_bit,
+ is_weakly_undefined_without_plt);
+ }
+
+ // R_ARM_XPC25: (S + A) | T - P
+ static inline typename This::Status
+ xpc25(const Relocate_info<32, big_endian>* relinfo,
+ unsigned char *view,
+ const Sized_symbol<32>* gsym,
+ const Arm_relobj<big_endian>* object,
+ unsigned int r_sym,
+ const Symbol_value<32>* psymval,
+ Arm_address address,
+ Arm_address thumb_bit,
+ bool is_weakly_undefined_without_plt)
+ {
+ return arm_branch_common(elfcpp::R_ARM_XPC25, relinfo, view, gsym,
+ object, r_sym, psymval, address, thumb_bit,
+ is_weakly_undefined_without_plt);
}
// R_ARM_CALL: (S + A) | T - P
static inline typename This::Status
- call(unsigned char *view,
- const Sized_relobj<32, big_endian>* object,
+ call(const Relocate_info<32, big_endian>* relinfo,
+ unsigned char *view,
+ const Sized_symbol<32>* gsym,
+ const Arm_relobj<big_endian>* object,
+ unsigned int r_sym,
const Symbol_value<32>* psymval,
Arm_address address,
- Arm_address thumb_bit)
+ Arm_address thumb_bit,
+ bool is_weakly_undefined_without_plt)
{
- return arm_branch_common<elfcpp::R_ARM_CALL>(view, object, psymval,
- address, thumb_bit);
+ return arm_branch_common(elfcpp::R_ARM_CALL, relinfo, view, gsym,
+ object, r_sym, psymval, address, thumb_bit,
+ is_weakly_undefined_without_plt);
}
// R_ARM_JUMP24: (S + A) | T - P
static inline typename This::Status
- jump24(unsigned char *view,
- const Sized_relobj<32, big_endian>* object,
+ jump24(const Relocate_info<32, big_endian>* relinfo,
+ unsigned char *view,
+ const Sized_symbol<32>* gsym,
+ const Arm_relobj<big_endian>* object,
+ unsigned int r_sym,
const Symbol_value<32>* psymval,
Arm_address address,
- Arm_address thumb_bit)
+ Arm_address thumb_bit,
+ bool is_weakly_undefined_without_plt)
{
- return arm_branch_common<elfcpp::R_ARM_JUMP24>(view, object, psymval,
- address, thumb_bit);
+ return arm_branch_common(elfcpp::R_ARM_JUMP24, relinfo, view, gsym,
+ object, r_sym, psymval, address, thumb_bit,
+ is_weakly_undefined_without_plt);
}
// R_ARM_PREL: (S + A) | T - P
}
};
+// Relocate ARM long branches. This handles relocation types
+// R_ARM_CALL, R_ARM_JUMP24, R_ARM_PLT32 and R_ARM_XPC25.
+// If IS_WEAK_UNDEFINED_WITH_PLT is true. The target symbol is weakly
+// undefined and we do not use PLT in this relocation. In such a case,
+// the branch is converted into an NOP.
+
+template<bool big_endian>
+typename Arm_relocate_functions<big_endian>::Status
+Arm_relocate_functions<big_endian>::arm_branch_common(
+ unsigned int r_type,
+ const Relocate_info<32, big_endian>* relinfo,
+ unsigned char *view,
+ const Sized_symbol<32>* gsym,
+ const Arm_relobj<big_endian>* object,
+ unsigned int r_sym,
+ const Symbol_value<32>* psymval,
+ Arm_address address,
+ Arm_address thumb_bit,
+ bool is_weakly_undefined_without_plt)
+{
+ typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype;
+ Valtype* wv = reinterpret_cast<Valtype*>(view);
+ Valtype val = elfcpp::Swap<32, big_endian>::readval(wv);
+
+ bool insn_is_b = (((val >> 28) & 0xf) <= 0xe)
+ && ((val & 0x0f000000UL) == 0x0a000000UL);
+ bool insn_is_uncond_bl = (val & 0xff000000UL) == 0xeb000000UL;
+ bool insn_is_cond_bl = (((val >> 28) & 0xf) < 0xe)
+ && ((val & 0x0f000000UL) == 0x0b000000UL);
+ bool insn_is_blx = (val & 0xfe000000UL) == 0xfa000000UL;
+ bool insn_is_any_branch = (val & 0x0e000000UL) == 0x0a000000UL;
+
+ // Check that the instruction is valid.
+ if (r_type == elfcpp::R_ARM_CALL)
+ {
+ if (!insn_is_uncond_bl && !insn_is_blx)
+ return This::STATUS_BAD_RELOC;
+ }
+ else if (r_type == elfcpp::R_ARM_JUMP24)
+ {
+ if (!insn_is_b && !insn_is_cond_bl)
+ return This::STATUS_BAD_RELOC;
+ }
+ else if (r_type == elfcpp::R_ARM_PLT32)
+ {
+ if (!insn_is_any_branch)
+ return This::STATUS_BAD_RELOC;
+ }
+ else if (r_type == elfcpp::R_ARM_XPC25)
+ {
+ // FIXME: AAELF document IH0044C does not say much about it other
+ // than it being obsolete.
+ if (!insn_is_any_branch)
+ return This::STATUS_BAD_RELOC;
+ }
+ else
+ gold_unreachable();
+
+ // A branch to an undefined weak symbol is turned into a jump to
+ // the next instruction unless a PLT entry will be created.
+ // Do the same for local undefined symbols.
+ // The jump to the next instruction is optimized as a NOP depending
+ // on the architecture.
+ const Target_arm<big_endian>* arm_target =
+ Target_arm<big_endian>::default_target();
+ if (is_weakly_undefined_without_plt)
+ {
+ Valtype cond = val & 0xf0000000U;
+ if (arm_target->may_use_arm_nop())
+ val = cond | 0x0320f000;
+ else
+ val = cond | 0x01a00000; // Using pre-UAL nop: mov r0, r0.
+ elfcpp::Swap<32, big_endian>::writeval(wv, val);
+ return This::STATUS_OKAY;
+ }
+
+ Valtype addend = utils::sign_extend<26>(val << 2);
+ Valtype branch_target = psymval->value(object, addend);
+ int32_t branch_offset = branch_target - address;
+
+ // We need a stub if the branch offset is too large or if we need
+ // to switch mode.
+ bool may_use_blx = arm_target->may_use_blx();
+ Reloc_stub* stub = NULL;
+ if ((branch_offset > ARM_MAX_FWD_BRANCH_OFFSET)
+ || (branch_offset < ARM_MAX_BWD_BRANCH_OFFSET)
+ || ((thumb_bit != 0) && !(may_use_blx && r_type == elfcpp::R_ARM_CALL)))
+ {
+ Stub_type stub_type =
+ Reloc_stub::stub_type_for_reloc(r_type, address, branch_target,
+ (thumb_bit != 0));
+ if (stub_type != arm_stub_none)
+ {
+ Stub_table<big_endian>* stub_table =
+ object->stub_table(relinfo->data_shndx);
+ gold_assert(stub_table != NULL);
+
+ Reloc_stub::Key stub_key(stub_type, gsym, object, r_sym, addend);
+ stub = stub_table->find_reloc_stub(stub_key);
+ gold_assert(stub != NULL);
+ thumb_bit = stub->stub_template()->entry_in_thumb_mode() ? 1 : 0;
+ branch_target = stub_table->address() + stub->offset() + addend;
+ branch_offset = branch_target - address;
+ gold_assert((branch_offset <= ARM_MAX_FWD_BRANCH_OFFSET)
+ && (branch_offset >= ARM_MAX_BWD_BRANCH_OFFSET));
+ }
+ }
+
+ // At this point, if we still need to switch mode, the instruction
+ // must either be a BLX or a BL that can be converted to a BLX.
+ if (thumb_bit != 0)
+ {
+ // Turn BL to BLX.
+ gold_assert(may_use_blx && r_type == elfcpp::R_ARM_CALL);
+ val = (val & 0xffffff) | 0xfa000000 | ((branch_offset & 2) << 23);
+ }
+
+ val = utils::bit_select(val, (branch_offset >> 2), 0xffffffUL);
+ elfcpp::Swap<32, big_endian>::writeval(wv, val);
+ return (utils::has_overflow<26>(branch_offset)
+ ? This::STATUS_OVERFLOW : This::STATUS_OKAY);
+}
+
// Get the GOT section, creating it if necessary.
template<bool big_endian>
// is 1. Otherwise it is 0.
Arm_address thumb_bit = 0;
Symbol_value<32> symval;
+ bool is_weakly_undefined_without_plt = false;
if (relnum != Target_arm<big_endian>::fake_relnum_for_stubs)
{
if (gsym != NULL)
+ gsym->plt_offset());
psymval = &symval;
}
+ else if (gsym->is_weak_undefined())
+ {
+ // This is a weakly undefined symbol and we do not use PLT
+ // for this relocation. A branch targeting this symbol will
+ // be converted into an NOP.
+ is_weakly_undefined_without_plt = true;
+ }
else
{
// Set thumb bit if symbol:
break;
}
+ // To look up relocation stubs, we need to pass the symbol table index of
+ // a local symbol.
+ unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
+
typename Arm_relocate_functions::Status reloc_status =
Arm_relocate_functions::STATUS_OKAY;
switch (r_type)
address, thumb_bit);
break;
+ case elfcpp::R_ARM_XPC25:
+ reloc_status =
+ Arm_relocate_functions::xpc25(relinfo, view, gsym, object, r_sym,
+ psymval, address, thumb_bit,
+ is_weakly_undefined_without_plt);
+ break;
+
case elfcpp::R_ARM_GOTOFF32:
{
Arm_address got_origin;
|| (gsym->is_defined()
&& !gsym->is_from_dynobj()
&& !gsym->is_preemptible()));
- reloc_status = Arm_relocate_functions::plt32(view, object, psymval,
- address, thumb_bit);
+ reloc_status =
+ Arm_relocate_functions::plt32(relinfo, view, gsym, object, r_sym,
+ psymval, address, thumb_bit,
+ is_weakly_undefined_without_plt);
break;
case elfcpp::R_ARM_CALL:
- reloc_status = Arm_relocate_functions::call(view, object, psymval,
- address, thumb_bit);
+ reloc_status =
+ Arm_relocate_functions::call(relinfo, view, gsym, object, r_sym,
+ psymval, address, thumb_bit,
+ is_weakly_undefined_without_plt);
break;
case elfcpp::R_ARM_JUMP24:
- reloc_status = Arm_relocate_functions::jump24(view, object, psymval,
- address, thumb_bit);
+ reloc_status =
+ Arm_relocate_functions::jump24(relinfo, view, gsym, object, r_sym,
+ psymval, address, thumb_bit,
+ is_weakly_undefined_without_plt);
break;
case elfcpp::R_ARM_PREL31:
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