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2009-11-25 Doug Kwan <dougkwan@google.com> 

* arm.cc (Target_arm::Target_arm): Move method definition outside of
	class definition.  Add code to handle --target1-rel, --target1-abs
	and --target2= options.
	(Target_arm::get_reloc_reloc_type): Change method to be non-static
	and const.
	(Target_arm::target1_is_rel_, Target_arm::target2_reloc_): New data
	member declaration.
	(Target_arm::Scan::local, Target_arm::Scan::global,
	Target_arm::Relocate::relocate,
	Target_arm::Relocatable_size_for_reloc::get_size_for_reloc): Adjust
	call to Target_arm::get_real_reloc_type.
	(Target_arm::get_real_reloc_type): Use command line options to
	determine real types of R_ARM_TARGET1 and R_ARM_TARGET2.
	* options.h (--target1-rel, --target1-abs, --target2): New ARM-only
	options.
This commit is contained in:
Doug Kwan 2009-11-25 04:11:56 +00:00
parent e2b8f3c401
commit 5193828376
2 changed files with 267 additions and 38 deletions
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16
gold/ChangeLog
View File

@ -1,3 +1,19 @@
2009-11-25 Doug Kwan <dougkwan@google.com>
* arm.cc (Target_arm::may_use_thumb2_nop): New method definition.
(Arm_relocate_functions::thumb_branch_common): New metod declaration.
(Arm_relocate_functions::abs12, Arm_relocate_functions::abs16): Fix
formatting.
(Arm_relocate_functions::thm_call): Replace body with a call to
Arm_relocate_functions::thumb_branch_common.
(Arm_relocate_functions::thm_jump24,
Arm_relocate_functions::thm_xpc22): New method definitions.
(Arm_relocate_functions::thumb_branch_common): New method definition.
(Reloc_stub::stbu_type_for_reloc): Fix incorrect uses of bit-wise-or
operator.
(Target_arm::Relocate::relocate): Adjust call to thm_call.
Add code to handle R_ARM_THM_XPC22 and R_ARM_THM_JUMP24.
2009-11-24 Rafael Avila de Espindola <espindola@google.com>
* Makefile.am: Build incremental-dump

289
gold/arm.cc
View File

@ -1195,6 +1195,14 @@ class Target_arm : public Sized_target<32, big_endian>
return false;
}
// Whether we have THUMB-2 NOP.W instruction.
bool
may_use_thumb2_nop() const
{
// FIXME: This should not hard-coded.
return false;
}
// Process the relocations to determine unreferenced sections for
// garbage collection.
void
@ -1750,6 +1758,13 @@ class Arm_relocate_functions : public Relocate_functions<32, big_endian>
const Arm_relobj<big_endian>*, unsigned int,
const Symbol_value<32>*, Arm_address, Arm_address, bool);
// Handle THUMB long branches.
static typename This::Status
thumb_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_ABS8: S + A
@ -1793,8 +1808,8 @@ class Arm_relocate_functions : public Relocate_functions<32, big_endian>
// R_ARM_ABS12: S + A
static inline typename This::Status
abs12(unsigned char *view,
const Sized_relobj<32, big_endian>* object,
const Symbol_value<32>* psymval)
const Sized_relobj<32, big_endian>* object,
const Symbol_value<32>* psymval)
{
typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype;
typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype;
@ -1812,8 +1827,8 @@ class Arm_relocate_functions : public Relocate_functions<32, big_endian>
// R_ARM_ABS16: S + A
static inline typename This::Status
abs16(unsigned char *view,
const Sized_relobj<32, big_endian>* object,
const Symbol_value<32>* psymval)
const Sized_relobj<32, big_endian>* object,
const Symbol_value<32>* psymval)
{
typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype;
typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype;
@ -1861,38 +1876,41 @@ class Arm_relocate_functions : public Relocate_functions<32, big_endian>
// R_ARM_THM_CALL: (S + A) | T - P
static inline typename This::Status
thm_call(unsigned char *view,
const Sized_relobj<32, big_endian>* object,
const Symbol_value<32>* psymval,
Arm_address address,
Arm_address thumb_bit)
thm_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,
bool is_weakly_undefined_without_plt)
{
// A thumb call consists of two instructions.
typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype;
typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype;
Valtype* wv = reinterpret_cast<Valtype*>(view);
Valtype hi = elfcpp::Swap<16, big_endian>::readval(wv);
Valtype lo = elfcpp::Swap<16, big_endian>::readval(wv + 1);
// Must be a BL instruction. lo == 11111xxxxxxxxxxx.
gold_assert((lo & 0xf800) == 0xf800);
Reltype addend = utils::sign_extend<23>(((hi & 0x7ff) << 12)
| ((lo & 0x7ff) << 1));
Reltype x = (psymval->value(object, addend) | thumb_bit) - address;
return thumb_branch_common(elfcpp::R_ARM_THM_CALL, relinfo, view, gsym,
object, r_sym, psymval, address, thumb_bit,
is_weakly_undefined_without_plt);
}
// If target has no thumb bit set, we need to either turn the BL
// into a BLX (for ARMv5 or above) or generate a stub.
if ((x & 1) == 0)
{
// This only works for ARMv5 and above with interworking enabled.
lo &= 0xefff;
}
hi = utils::bit_select(hi, (x >> 12), 0x7ffU);
lo = utils::bit_select(lo, (x >> 1), 0x7ffU);
elfcpp::Swap<16, big_endian>::writeval(wv, hi);
elfcpp::Swap<16, big_endian>::writeval(wv + 1, lo);
return (utils::has_overflow<23>(x)
? This::STATUS_OVERFLOW
: This::STATUS_OKAY);
// R_ARM_THM_JUMP24: (S + A) | T - P
static inline typename This::Status
thm_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,
bool is_weakly_undefined_without_plt)
{
return thumb_branch_common(elfcpp::R_ARM_THM_JUMP24, relinfo, view, gsym,
object, r_sym, psymval, address, thumb_bit,
is_weakly_undefined_without_plt);
}
// R_ARM_THM_XPC22: (S + A) | T - P
static inline typename This::Status
thm_xpc22(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 thumb_branch_common(elfcpp::R_ARM_THM_XPC22, relinfo, view, gsym,
object, r_sym, psymval, address, thumb_bit,
is_weakly_undefined_without_plt);
}
// R_ARM_BASE_PREL: B(S) + A - P
@ -2292,6 +2310,183 @@ Arm_relocate_functions<big_endian>::arm_branch_common(
? This::STATUS_OVERFLOW : This::STATUS_OKAY);
}
// Relocate THUMB long branches. This handles relocation types
// R_ARM_THM_CALL, R_ARM_THM_JUMP24 and R_ARM_THM_XPC22.
// 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>::thumb_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<16, big_endian>::Valtype Valtype;
Valtype* wv = reinterpret_cast<Valtype*>(view);
uint32_t upper_insn = elfcpp::Swap<16, big_endian>::readval(wv);
uint32_t lower_insn = elfcpp::Swap<16, big_endian>::readval(wv + 1);
// FIXME: These tests are too loose and do not take THUMB/THUMB-2 difference
// into account.
bool is_bl_insn = (lower_insn & 0x1000U) == 0x1000U;
bool is_blx_insn = (lower_insn & 0x1000U) == 0x0000U;
// Check that the instruction is valid.
if (r_type == elfcpp::R_ARM_THM_CALL)
{
if (!is_bl_insn && !is_blx_insn)
return This::STATUS_BAD_RELOC;
}
else if (r_type == elfcpp::R_ARM_THM_JUMP24)
{
// This cannot be a BLX.
if (!is_bl_insn)
return This::STATUS_BAD_RELOC;
}
else if (r_type == elfcpp::R_ARM_THM_XPC22)
{
// Check for Thumb to Thumb call.
if (!is_blx_insn)
return This::STATUS_BAD_RELOC;
if (thumb_bit != 0)
{
gold_warning(_("%s: Thumb BLX instruction targets "
"thumb function '%s'."),
object->name().c_str(),
(gsym ? gsym->name() : "(local)"));
// Convert BLX to BL.
lower_insn |= 0x1000U;
}
}
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.
// The jump to the next instruction is optimized as a NOP.W for
// Thumb-2 enabled architectures.
const Target_arm<big_endian>* arm_target =
Target_arm<big_endian>::default_target();
if (is_weakly_undefined_without_plt)
{
if (arm_target->may_use_thumb2_nop())
{
elfcpp::Swap<16, big_endian>::writeval(wv, 0xf3af);
elfcpp::Swap<16, big_endian>::writeval(wv + 1, 0x8000);
}
else
{
elfcpp::Swap<16, big_endian>::writeval(wv, 0xe000);
elfcpp::Swap<16, big_endian>::writeval(wv + 1, 0xbf00);
}
return This::STATUS_OKAY;
}
// Fetch the addend. We use the Thumb-2 encoding (backwards compatible
// with Thumb-1) involving the J1 and J2 bits.
uint32_t s = (upper_insn & (1 << 10)) >> 10;
uint32_t upper = upper_insn & 0x3ff;
uint32_t lower = lower_insn & 0x7ff;
uint32_t j1 = (lower_insn & (1 << 13)) >> 13;
uint32_t j2 = (lower_insn & (1 << 11)) >> 11;
uint32_t i1 = j1 ^ s ? 0 : 1;
uint32_t i2 = j2 ^ s ? 0 : 1;
int32_t addend = (i1 << 23) | (i2 << 22) | (upper << 12) | (lower << 1);
// Sign extend.
addend = (addend | ((s ? 0 : 1) << 24)) - (1 << 24);
Arm_address 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();
bool thumb2 = arm_target->using_thumb2();
if ((!thumb2
&& (branch_offset > THM_MAX_FWD_BRANCH_OFFSET
|| (branch_offset < THM_MAX_BWD_BRANCH_OFFSET)))
|| (thumb2
&& (branch_offset > THM2_MAX_FWD_BRANCH_OFFSET
|| (branch_offset < THM2_MAX_BWD_BRANCH_OFFSET)))
|| ((thumb_bit == 0)
&& (((r_type == elfcpp::R_ARM_THM_CALL) && !may_use_blx)
|| r_type == elfcpp::R_ARM_THM_JUMP24)))
{
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);
Reloc_stub* 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;
}
}
// 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)
{
gold_assert(may_use_blx
&& (r_type == elfcpp::R_ARM_THM_CALL
|| r_type == elfcpp::R_ARM_THM_XPC22));
// Make sure this is a BLX.
lower_insn &= ~0x1000U;
}
else
{
// Make sure this is a BL.
lower_insn |= 0x1000U;
}
uint32_t reloc_sign = (branch_offset < 0) ? 1 : 0;
uint32_t relocation = static_cast<uint32_t>(branch_offset);
if ((lower_insn & 0x5000U) == 0x4000U)
// For a BLX instruction, make sure that the relocation is rounded up
// to a word boundary. This follows the semantics of the instruction
// which specifies that bit 1 of the target address will come from bit
// 1 of the base address.
relocation = (relocation + 2U) & ~3U;
// Put BRANCH_OFFSET back into the insn. Assumes two's complement.
// We use the Thumb-2 encoding, which is safe even if dealing with
// a Thumb-1 instruction by virtue of our overflow check above. */
upper_insn = (upper_insn & ~0x7ffU)
| ((relocation >> 12) & 0x3ffU)
| (reloc_sign << 10);
lower_insn = (lower_insn & ~0x2fffU)
| (((!((relocation >> 23) & 1U)) ^ reloc_sign) << 13)
| (((!((relocation >> 22) & 1U)) ^ reloc_sign) << 11)
| ((relocation >> 1) & 0x7ffU);
elfcpp::Swap<16, big_endian>::writeval(wv, upper_insn);
elfcpp::Swap<16, big_endian>::writeval(wv + 1, lower_insn);
return ((thumb2
? utils::has_overflow<25>(relocation)
: utils::has_overflow<23>(relocation))
? This::STATUS_OVERFLOW
: This::STATUS_OKAY);
}
// Get the GOT section, creating it if necessary.
template<bool big_endian>
@ -2543,7 +2738,8 @@ Reloc_stub::stub_type_for_reloc(
// Thumb to thumb.
if (!thumb_only)
{
stub_type = (parameters->options().shared() | should_force_pic_veneer)
stub_type = (parameters->options().shared()
|| should_force_pic_veneer)
// PIC stubs.
? ((may_use_blx
&& (r_type == elfcpp::R_ARM_THM_CALL))
@ -2563,7 +2759,8 @@ Reloc_stub::stub_type_for_reloc(
}
else
{
stub_type = (parameters->options().shared() | should_force_pic_veneer)
stub_type = (parameters->options().shared()
|| should_force_pic_veneer)
? arm_stub_long_branch_thumb_only_pic // PIC stub.
: arm_stub_long_branch_thumb_only; // non-PIC stub.
}
@ -4729,8 +4926,10 @@ Target_arm<big_endian>::Relocate::relocate(
break;
case elfcpp::R_ARM_THM_CALL:
reloc_status = Arm_relocate_functions::thm_call(view, object, psymval,
address, thumb_bit);
reloc_status =
Arm_relocate_functions::thm_call(relinfo, view, gsym, object, r_sym,
psymval, address, thumb_bit,
is_weakly_undefined_without_plt);
break;
case elfcpp::R_ARM_XPC25:
@ -4740,6 +4939,13 @@ Target_arm<big_endian>::Relocate::relocate(
is_weakly_undefined_without_plt);
break;
case elfcpp::R_ARM_THM_XPC22:
reloc_status =
Arm_relocate_functions::thm_xpc22(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;
@ -4842,6 +5048,13 @@ Target_arm<big_endian>::Relocate::relocate(
is_weakly_undefined_without_plt);
break;
case elfcpp::R_ARM_THM_JUMP24:
reloc_status =
Arm_relocate_functions::thm_jump24(relinfo, view, gsym, object, r_sym,
psymval, address, thumb_bit,
is_weakly_undefined_without_plt);
break;
case elfcpp::R_ARM_PREL31:
reloc_status = Arm_relocate_functions::prel31(view, object, psymval,
address, thumb_bit);