[PATCH][GOLD] Handle bit-1 of THUMB BLX target address correctly.
Doug Kwan (關振德)
dougkwan@google.com
Mon Mar 22 21:56:00 GMT 2010
Hi,
This patch fixes the handling of bit-1 of THUMB BLX target
address, which comes from bit-1 of the branch base address. The patch
makes the treatment consistent in all parts of the ARM back-end. The
patch extends the current testing for stubs to cover boundary cases
involving BLX.
-Doug
2010-03-22 Doug Kwan <dougkwan@google.com>
* arm.cc (Arm_relocate_functions::abs8,
Arm_relocate_functions::abs16): Use correct check for overflow
specified in the ARM ELF specs.
(Arm_relocate_functions): thumb_branch_common. Handle bit 1 of branch
target of a BLX instruction specially.
(Reloc_stub::stub_type_for_reloc): Ditto.
(Relocate::relocate): Use symbolic names instead of numeric relocation
codes to report error.
(Target_arm::do_relox): Reduce default stub-group size for Cortex-A8
workaround.
* testsuite/Makefile.am (check_DATA): add thumb_blx_in_range.stdout,
thumb_blx_out_of_range.stdout, thumb2_blx_in_range.stdout and
thumb2_blx_out_of_range.stdout
(thumb_bl_out_of_range, thumb_bl_out_of_range.o,
thumb2_bl_out_of_range, thumb2_bl_out_of_range.o): Fix dependenices.
(thumb_blx_in_range.stdout, thumb_blx_in_range, thumb_blx_in_range.o,
thumb_blx_out_of_range.stdout, thumb_blx_out_of_range,
thumb_blx_out_of_range.o, thumb2_blx_in_range.stdout,
thumb2_blx_in_range, thumb2_blx_in_range.o,
thumb2_blx_out_of_range.stdout, thumb2_blx_out_of_range,
thumb2_blx_out_of_range.o): New rules.
(MOSTLYCLEANFILES): Add thumb_blx_in_range, thumb_blx_out_of_range,
thumb2_blx_in_range and thumb2_blx_out_of_range.
* testsuite/Makefile.in: Regenerate.
* arm_branch_in_range.sh: Add tests for THUMB BLX.
* testsuite/thumb_blx_in_range.s: New file.
* testsuite/thumb_blx_out_of_range.s: New file.
-------------- next part --------------
Index: gold/arm.cc
===================================================================
RCS file: /cvs/src/src/gold/arm.cc,v
retrieving revision 1.93
diff -u -u -p -r1.93 arm.cc
--- gold/arm.cc 19 Mar 2010 19:11:21 -0000 1.93
+++ gold/arm.cc 22 Mar 2010 18:45:32 -0000
@@ -2985,7 +2985,10 @@ class Arm_relocate_functions : public Re
Reltype x = psymval->value(object, addend);
val = utils::bit_select(val, x, 0xffU);
elfcpp::Swap<8, big_endian>::writeval(wv, val);
- return (utils::has_signed_unsigned_overflow<8>(x)
+
+ // R_ARM_ABS8 permits signed or unsigned results.
+ int signed_x = static_cast<int32_t>(x);
+ return ((signed_x < -128 || signed_x > 255)
? This::STATUS_OVERFLOW
: This::STATUS_OKAY);
}
@@ -3004,7 +3007,10 @@ class Arm_relocate_functions : public Re
Reltype x = psymval->value(object, addend);
val = utils::bit_select(val, x << 6, 0x7e0U);
elfcpp::Swap<16, big_endian>::writeval(wv, val);
- return (utils::has_overflow<5>(x)
+
+ // R_ARM_ABS16 permits signed or unsigned results.
+ int signed_x = static_cast<int32_t>(x);
+ return ((signed_x < -32768 || signed_x > 65535)
? This::STATUS_OVERFLOW
: This::STATUS_OKAY);
}
@@ -3831,11 +3837,16 @@ Arm_relocate_functions<big_endian>::thum
int32_t addend = This::thumb32_branch_offset(upper_insn, lower_insn);
Arm_address branch_target = psymval->value(object, addend);
+
+ // For BLX, bit 1 of target address comes from bit 1 of base address.
+ bool may_use_blx = arm_target->may_use_blx();
+ if (thumb_bit == 0 && may_use_blx)
+ branch_target = utils::bit_select(branch_target, address, 0x2);
+
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 && utils::has_overflow<23>(branch_offset))
|| (thumb2 && utils::has_overflow<25>(branch_offset))
@@ -3861,6 +3872,8 @@ Arm_relocate_functions<big_endian>::thum
gold_assert(stub != NULL);
thumb_bit = stub->stub_template()->entry_in_thumb_mode() ? 1 : 0;
branch_target = stub_table->address() + stub->offset() + addend;
+ if (thumb_bit == 0 && may_use_blx)
+ branch_target = utils::bit_select(branch_target, address, 0x2);
branch_offset = branch_target - address;
}
}
@@ -3881,12 +3894,12 @@ Arm_relocate_functions<big_endian>::thum
lower_insn |= 0x1000U;
}
+ // 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.
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.
- branch_offset = (branch_offset + 2) & ~3;
+ gold_assert((branch_offset & 3) == 0);
// Put BRANCH_OFFSET back into the insn. Assumes two's complement.
// We use the Thumb-2 encoding, which is safe even if dealing with
@@ -3897,6 +3910,8 @@ Arm_relocate_functions<big_endian>::thum
elfcpp::Swap<16, big_endian>::writeval(wv, upper_insn);
elfcpp::Swap<16, big_endian>::writeval(wv + 1, lower_insn);
+ gold_assert(!utils::has_overflow<25>(branch_offset));
+
return ((thumb2
? utils::has_overflow<25>(branch_offset)
: utils::has_overflow<23>(branch_offset))
@@ -4225,10 +4240,15 @@ Reloc_stub::stub_type_for_reloc(
thumb_only = little_endian_target->using_thumb_only();
}
- int64_t branch_offset = (int64_t)destination - location;
-
+ int64_t branch_offset;
if (r_type == elfcpp::R_ARM_THM_CALL || r_type == elfcpp::R_ARM_THM_JUMP24)
{
+ // For THUMB BLX instruction, bit 1 of target comes from bit 1 of the
+ // base address (instruction address + 4).
+ if ((r_type == elfcpp::R_ARM_THM_CALL) && may_use_blx && !target_is_thumb)
+ destination = utils::bit_select(destination, location, 0x2);
+ branch_offset = (int64_t)destination - location;
+
// Handle cases where:
// - this call goes too far (different Thumb/Thumb2 max
// distance)
@@ -4309,6 +4329,7 @@ Reloc_stub::stub_type_for_reloc(
|| r_type == elfcpp::R_ARM_JUMP24
|| r_type == elfcpp::R_ARM_PLT32)
{
+ branch_offset = (int64_t)destination - location;
if (target_is_thumb)
{
// Arm to thumb.
@@ -8562,16 +8583,16 @@ Target_arm<big_endian>::Relocate::reloca
break;
case Arm_relocate_functions::STATUS_OVERFLOW:
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
- _("relocation overflow in relocation %u"),
- r_type);
+ _("relocation overflow in %s"),
+ reloc_property->name().c_str());
break;
case Arm_relocate_functions::STATUS_BAD_RELOC:
gold_error_at_location(
relinfo,
relnum,
rel.get_r_offset(),
- _("unexpected opcode while processing relocation %u"),
- r_type);
+ _("unexpected opcode while processing relocation %s"),
+ reloc_property->name().c_str());
break;
default:
gold_unreachable();
@@ -10297,13 +10318,18 @@ Target_arm<big_endian>::do_relax(
// Default value.
// Thumb branch range is +-4MB has to be used as the default
// maximum size (a given section can contain both ARM and Thumb
- // code, so the worst case has to be taken into account).
+ // code, so the worst case has to be taken into account). If we are
+ // fixing cortex-a8 errata, the branch range has to be even smaller,
+ // since wide conditional branch has a range of +-1MB only.
//
// This value is 24K less than that, which allows for 2025
// 12-byte stubs. If we exceed that, then we will fail to link.
// The user will have to relink with an explicit group size
// option.
- stub_group_size = 4170000;
+ if (this->fix_cortex_a8_)
+ stub_group_size = 1024276;
+ else
+ stub_group_size = 4170000;
}
group_sections(layout, stub_group_size, stubs_always_after_branch);
Index: gold/testsuite/Makefile.am
===================================================================
RCS file: /cvs/src/src/gold/testsuite/Makefile.am,v
retrieving revision 1.125
diff -u -u -p -r1.125 Makefile.am
--- gold/testsuite/Makefile.am 3 Mar 2010 19:31:54 -0000 1.125
+++ gold/testsuite/Makefile.am 22 Mar 2010 18:45:32 -0000
@@ -1488,7 +1488,9 @@ MOSTLYCLEANFILES += arm_abs_global
check_SCRIPTS += arm_branch_in_range.sh
check_DATA += arm_bl_in_range.stdout arm_bl_out_of_range.stdout \
thumb_bl_in_range.stdout thumb_bl_out_of_range.stdout \
- thumb2_bl_in_range.stdout thumb2_bl_out_of_range.stdout
+ thumb2_bl_in_range.stdout thumb2_bl_out_of_range.stdout \
+ thumb_blx_in_range.stdout thumb_blx_out_of_range.stdout \
+ thumb2_blx_in_range.stdout thumb2_blx_out_of_range.stdout
arm_bl_in_range.stdout: arm_bl_in_range
$(TEST_OBJDUMP) -D $< > $@
@@ -1520,10 +1522,10 @@ thumb_bl_in_range.o: thumb_bl_in_range.s
thumb_bl_out_of_range.stdout: thumb_bl_out_of_range
$(TEST_OBJDUMP) -D $< > $@
-thumb_bl_out_of_range: thumb_bl_in_range.o ../ld-new
+thumb_bl_out_of_range: thumb_bl_out_of_range.o ../ld-new
../ld-new -T $(srcdir)/thumb_branch_range.t -o $@ $<
-thumb_bl_out_of_range.o: thumb_bl_in_range.s
+thumb_bl_out_of_range.o: thumb_bl_out_of_range.s
$(TEST_AS) -o $@ -march=armv5te $<
thumb2_bl_in_range.stdout: thumb2_bl_in_range
@@ -1538,14 +1540,52 @@ thumb2_bl_in_range.o: thumb_bl_in_range.
thumb2_bl_out_of_range.stdout: thumb2_bl_out_of_range
$(TEST_OBJDUMP) -D $< > $@
-thumb2_bl_out_of_range: thumb2_bl_in_range.o ../ld-new
+thumb2_bl_out_of_range: thumb2_bl_out_of_range.o ../ld-new
../ld-new -T $(srcdir)/thumb2_branch_range.t -o $@ $<
-thumb2_bl_out_of_range.o: thumb_bl_in_range.s
+thumb2_bl_out_of_range.o: thumb_bl_out_of_range.s
+ $(TEST_AS) -o $@ -march=armv7-a $<
+
+thumb_blx_in_range.stdout: thumb_blx_in_range
+ $(TEST_OBJDUMP) -D $< > $@
+
+thumb_blx_in_range: thumb_blx_in_range.o ../ld-new
+ ../ld-new -T $(srcdir)/thumb_branch_range.t -o $@ $<
+
+thumb_blx_in_range.o: thumb_blx_in_range.s
+ $(TEST_AS) -o $@ -march=armv5te $<
+
+thumb_blx_out_of_range.stdout: thumb_blx_out_of_range
+ $(TEST_OBJDUMP) -D $< > $@
+
+thumb_blx_out_of_range: thumb_blx_out_of_range.o ../ld-new
+ ../ld-new -T $(srcdir)/thumb_branch_range.t -o $@ $<
+
+thumb_blx_out_of_range.o: thumb_blx_out_of_range.s
+ $(TEST_AS) -o $@ -march=armv5te $<
+
+thumb2_blx_in_range.stdout: thumb2_blx_in_range
+ $(TEST_OBJDUMP) -D $< > $@
+
+thumb2_blx_in_range: thumb2_blx_in_range.o ../ld-new
+ ../ld-new -T $(srcdir)/thumb2_branch_range.t -o $@ $<
+
+thumb2_blx_in_range.o: thumb_blx_in_range.s
+ $(TEST_AS) -o $@ -march=armv7-a $<
+
+thumb2_blx_out_of_range.stdout: thumb2_blx_out_of_range
+ $(TEST_OBJDUMP) -D $< > $@
+
+thumb2_blx_out_of_range: thumb2_blx_out_of_range.o ../ld-new
+ ../ld-new -T $(srcdir)/thumb2_branch_range.t -o $@ $<
+
+thumb2_blx_out_of_range.o: thumb_blx_out_of_range.s
$(TEST_AS) -o $@ -march=armv7-a $<
MOSTLYCLEANFILES += arm_bl_in_range arm_bl_out_of_range thumb_bl_in_range \
- thumb_bl_out_of_range thumb2_bl_in_range thumb2_bl_out_of_range
+ thumb_bl_out_of_range thumb2_bl_in_range thumb2_bl_out_of_range \
+ thumb_blx_in_range thumb_blx_out_of_range thumb2_blx_in_range \
+ thumb2_blx_out_of_range
check_SCRIPTS += arm_fix_v4bx.sh
check_DATA += arm_fix_v4bx.stdout arm_fix_v4bx_interworking.stdout \
Index: gold/testsuite/Makefile.in
===================================================================
RCS file: /cvs/src/src/gold/testsuite/Makefile.in,v
retrieving revision 1.131
diff -u -u -p -r1.131 Makefile.in
--- gold/testsuite/Makefile.in 3 Mar 2010 19:31:54 -0000 1.131
+++ gold/testsuite/Makefile.in 22 Mar 2010 18:45:32 -0000
@@ -338,6 +338,10 @@ check_PROGRAMS = object_unittest$(EXEEXT
@DEFAULT_TARGET_ARM_TRUE@ thumb_bl_out_of_range.stdout \
@DEFAULT_TARGET_ARM_TRUE@ thumb2_bl_in_range.stdout \
@DEFAULT_TARGET_ARM_TRUE@ thumb2_bl_out_of_range.stdout \
+@DEFAULT_TARGET_ARM_TRUE@ thumb_blx_in_range.stdout \
+@DEFAULT_TARGET_ARM_TRUE@ thumb_blx_out_of_range.stdout \
+@DEFAULT_TARGET_ARM_TRUE@ thumb2_blx_in_range.stdout \
+@DEFAULT_TARGET_ARM_TRUE@ thumb2_blx_out_of_range.stdout \
@DEFAULT_TARGET_ARM_TRUE@ arm_fix_v4bx.stdout \
@DEFAULT_TARGET_ARM_TRUE@ arm_fix_v4bx_interworking.stdout \
@DEFAULT_TARGET_ARM_TRUE@ arm_no_fix_v4bx.stdout
@@ -346,7 +350,11 @@ check_PROGRAMS = object_unittest$(EXEEXT
@DEFAULT_TARGET_ARM_TRUE@ thumb_bl_in_range \
@DEFAULT_TARGET_ARM_TRUE@ thumb_bl_out_of_range \
@DEFAULT_TARGET_ARM_TRUE@ thumb2_bl_in_range \
-@DEFAULT_TARGET_ARM_TRUE@ thumb2_bl_out_of_range arm_fix_v4bx \
+@DEFAULT_TARGET_ARM_TRUE@ thumb2_bl_out_of_range \
+@DEFAULT_TARGET_ARM_TRUE@ thumb_blx_in_range \
+@DEFAULT_TARGET_ARM_TRUE@ thumb_blx_out_of_range \
+@DEFAULT_TARGET_ARM_TRUE@ thumb2_blx_in_range \
+@DEFAULT_TARGET_ARM_TRUE@ thumb2_blx_out_of_range arm_fix_v4bx \
@DEFAULT_TARGET_ARM_TRUE@ arm_fix_v4bx_interworking \
@DEFAULT_TARGET_ARM_TRUE@ arm_no_fix_v4bx
subdir = testsuite
@@ -3288,10 +3296,10 @@ uninstall-am:
@DEFAULT_TARGET_ARM_TRUE@thumb_bl_out_of_range.stdout: thumb_bl_out_of_range
@DEFAULT_TARGET_ARM_TRUE@ $(TEST_OBJDUMP) -D $< > $@
-@DEFAULT_TARGET_ARM_TRUE@thumb_bl_out_of_range: thumb_bl_in_range.o ../ld-new
+@DEFAULT_TARGET_ARM_TRUE@thumb_bl_out_of_range: thumb_bl_out_of_range.o ../ld-new
@DEFAULT_TARGET_ARM_TRUE@ ../ld-new -T $(srcdir)/thumb_branch_range.t -o $@ $<
-@DEFAULT_TARGET_ARM_TRUE@thumb_bl_out_of_range.o: thumb_bl_in_range.s
+@DEFAULT_TARGET_ARM_TRUE@thumb_bl_out_of_range.o: thumb_bl_out_of_range.s
@DEFAULT_TARGET_ARM_TRUE@ $(TEST_AS) -o $@ -march=armv5te $<
@DEFAULT_TARGET_ARM_TRUE@thumb2_bl_in_range.stdout: thumb2_bl_in_range
@@ -3306,10 +3314,46 @@ uninstall-am:
@DEFAULT_TARGET_ARM_TRUE@thumb2_bl_out_of_range.stdout: thumb2_bl_out_of_range
@DEFAULT_TARGET_ARM_TRUE@ $(TEST_OBJDUMP) -D $< > $@
-@DEFAULT_TARGET_ARM_TRUE@thumb2_bl_out_of_range: thumb2_bl_in_range.o ../ld-new
+@DEFAULT_TARGET_ARM_TRUE@thumb2_bl_out_of_range: thumb2_bl_out_of_range.o ../ld-new
@DEFAULT_TARGET_ARM_TRUE@ ../ld-new -T $(srcdir)/thumb2_branch_range.t -o $@ $<
-@DEFAULT_TARGET_ARM_TRUE@thumb2_bl_out_of_range.o: thumb_bl_in_range.s
+@DEFAULT_TARGET_ARM_TRUE@thumb2_bl_out_of_range.o: thumb_bl_out_of_range.s
+@DEFAULT_TARGET_ARM_TRUE@ $(TEST_AS) -o $@ -march=armv7-a $<
+
+@DEFAULT_TARGET_ARM_TRUE@thumb_blx_in_range.stdout: thumb_blx_in_range
+@DEFAULT_TARGET_ARM_TRUE@ $(TEST_OBJDUMP) -D $< > $@
+
+@DEFAULT_TARGET_ARM_TRUE@thumb_blx_in_range: thumb_blx_in_range.o ../ld-new
+@DEFAULT_TARGET_ARM_TRUE@ ../ld-new -T $(srcdir)/thumb_branch_range.t -o $@ $<
+
+@DEFAULT_TARGET_ARM_TRUE@thumb_blx_in_range.o: thumb_blx_in_range.s
+@DEFAULT_TARGET_ARM_TRUE@ $(TEST_AS) -o $@ -march=armv5te $<
+
+@DEFAULT_TARGET_ARM_TRUE@thumb_blx_out_of_range.stdout: thumb_blx_out_of_range
+@DEFAULT_TARGET_ARM_TRUE@ $(TEST_OBJDUMP) -D $< > $@
+
+@DEFAULT_TARGET_ARM_TRUE@thumb_blx_out_of_range: thumb_blx_out_of_range.o ../ld-new
+@DEFAULT_TARGET_ARM_TRUE@ ../ld-new -T $(srcdir)/thumb_branch_range.t -o $@ $<
+
+@DEFAULT_TARGET_ARM_TRUE@thumb_blx_out_of_range.o: thumb_blx_out_of_range.s
+@DEFAULT_TARGET_ARM_TRUE@ $(TEST_AS) -o $@ -march=armv5te $<
+
+@DEFAULT_TARGET_ARM_TRUE@thumb2_blx_in_range.stdout: thumb2_blx_in_range
+@DEFAULT_TARGET_ARM_TRUE@ $(TEST_OBJDUMP) -D $< > $@
+
+@DEFAULT_TARGET_ARM_TRUE@thumb2_blx_in_range: thumb2_blx_in_range.o ../ld-new
+@DEFAULT_TARGET_ARM_TRUE@ ../ld-new -T $(srcdir)/thumb2_branch_range.t -o $@ $<
+
+@DEFAULT_TARGET_ARM_TRUE@thumb2_blx_in_range.o: thumb_blx_in_range.s
+@DEFAULT_TARGET_ARM_TRUE@ $(TEST_AS) -o $@ -march=armv7-a $<
+
+@DEFAULT_TARGET_ARM_TRUE@thumb2_blx_out_of_range.stdout: thumb2_blx_out_of_range
+@DEFAULT_TARGET_ARM_TRUE@ $(TEST_OBJDUMP) -D $< > $@
+
+@DEFAULT_TARGET_ARM_TRUE@thumb2_blx_out_of_range: thumb2_blx_out_of_range.o ../ld-new
+@DEFAULT_TARGET_ARM_TRUE@ ../ld-new -T $(srcdir)/thumb2_branch_range.t -o $@ $<
+
+@DEFAULT_TARGET_ARM_TRUE@thumb2_blx_out_of_range.o: thumb_blx_out_of_range.s
@DEFAULT_TARGET_ARM_TRUE@ $(TEST_AS) -o $@ -march=armv7-a $<
@DEFAULT_TARGET_ARM_TRUE@arm_fix_v4bx.stdout: arm_fix_v4bx
Index: gold/testsuite/arm_branch_in_range.sh
===================================================================
RCS file: /cvs/src/src/gold/testsuite/arm_branch_in_range.sh,v
retrieving revision 1.1
diff -u -u -p -r1.1 arm_branch_in_range.sh
--- gold/testsuite/arm_branch_in_range.sh 22 Feb 2010 06:26:07 -0000 1.1
+++ gold/testsuite/arm_branch_in_range.sh 22 Mar 2010 18:45:32 -0000
@@ -53,5 +53,12 @@ check thumb2_bl_in_range.stdout \
" 2000004: f400 d000 bl 1000008 <_backward_target>"
check thumb2_bl_in_range.stdout \
" 2000008: f3ff d7ff bl 300000a <_forward_target>"
-
+check thumb_blx_in_range.stdout \
+ " 800006: f400 e800 blx 400008 <_backward_target>"
+check thumb_blx_in_range.stdout \
+ " 80000c: f3ff effe blx c0000c <_forward_target>"
+check thumb2_blx_in_range.stdout \
+ " 2000006: f400 c000 blx 1000008 <_backward_target>"
+check thumb2_blx_in_range.stdout \
+ " 200000c: f3ff c7fe blx 300000c <_forward_target>"
exit 0
Index: gold/testsuite/thumb_blx_in_range.s
===================================================================
RCS file: gold/testsuite/thumb_blx_in_range.s
diff -N gold/testsuite/thumb_blx_in_range.s
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ gold/testsuite/thumb_blx_in_range.s 22 Mar 2010 18:45:32 -0000
@@ -0,0 +1,64 @@
+# thumb_blx_in_range.s
+#
+# Test THUMB/THUMB-2 blx instructions just within the branch range limits.
+# Because bit 1 of the branch target comes from the branch instruction
+# address, the branch range from PC (branch instruction address + 4) is
+# acutally -((1<<22) + 2) to ((1<<22) - 4) for THUMB and -((1<<24) + 2) to
+# ((1<<24) - 4) from THUMB2.
+
+ .syntax unified
+ .section .text.pre,"x"
+
+# Add padding so that target is just in branch range.
+ .space 8
+
+ .align 2
+ .global _backward_target
+ .code 32
+ .type _backword_target, %function
+_backward_target:
+ bx lr
+ .size _backward_target, .-_backward_target
+
+ .text
+
+# Define _start so that linker does not complain.
+ .global _start
+ .code 32
+ .align 2
+ .type _start, %function
+_start:
+ bx lr
+ .size _start, .-_start
+
+ .global _backward_test
+ .code 16
+ .thumb_func
+ .type _backward_test, %function
+_backward_test:
+ nop.n
+ blx _backward_target
+ .size _backward_test, .-_backward_test
+
+ .align 2
+ .global _forward_test
+ .code 16
+ .thumb_func
+ .type _forward_test, %function
+_forward_test:
+ blx _forward_target
+ .size _forward_test, .-_forward_test
+ .code 32
+
+ .section .text.post,"x"
+
+# Add padding so that target is just in branch range.
+ .space 12
+
+ .align 2
+ .global _forward_target
+ .code 32
+ .type _forward_target, %function
+_forward_target:
+ bx lr
+ .size _forward_target, .-_forward_target
Index: gold/testsuite/thumb_blx_out_of_range.s
===================================================================
RCS file: gold/testsuite/thumb_blx_out_of_range.s
diff -N gold/testsuite/thumb_blx_out_of_range.s
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ gold/testsuite/thumb_blx_out_of_range.s 22 Mar 2010 18:45:32 -0000
@@ -0,0 +1,61 @@
+# thumb_blx_out_of_range.s
+# Test THUMB/THUMB-2 blx instructions just out of the branch range limits.
+ .syntax unified
+
+ .section .text.pre,"x"
+
+# Add padding so that target is just output of branch range.
+ .space 6
+
+ .global _forward_target
+ .global _backward_target
+ .type _backword_target, %function
+_backward_target:
+ bx lr
+ .size _backward_target, .-_backward_target
+
+ .text
+
+# Define _start so that linker does not complain.
+ .align 2
+ .global _start
+ .code 32
+ .type _start, %function
+_start:
+ bx lr
+ .size _start, .-_start
+
+ .global _backward_test
+ .code 16
+ .thumb_func
+ .type _backward_test, %function
+_backward_test:
+ bl _backward_target
+ .size _backward_test, .-_backward_test
+
+ .align 2
+ .global _forward_test
+ .code 16
+ .thumb_func
+ .type _forward_test, %function
+_forward_test:
+ # Bit 1 of the BLX target comes from bit 1 of branch base address,
+ # which is BLX instruction's address + 4. We intentionally put this
+ # forward BLX at an address n*4 + 2 so that the branch offset is
+ # bumped up by 2.
+ nop.n
+ bl _forward_target
+ .size _forward_test, .-_forward_test
+ .code 32
+
+ .section .text.post,"x"
+
+# Add padding so that target is just out of branch range.
+ .space 12
+ .align 2
+ .code 32
+ .global _forward_target
+ .type _forward_target, %function
+_forward_target:
+ bx lr
+ .size _forward_target, .-_forward_target
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