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| author | Christophe Lyon <christophe.lyon@linaro.org> | 2024-09-06 17:10:02 +0000 |
|---|---|---|
| committer | Christophe Lyon <christophe.lyon@linaro.org> | 2024-09-11 15:34:32 +0000 |
| commit | a77ccc81295f41b72f96db000d1aa44e4dc91254 (patch) | |
| tree | fe8e072af55498a7d07c80b9c601bf6c0e7ea6fe | |
| parent | 1628e02267448cd82e219a60a4ed37cfa18fd35a (diff) | |
| download | gdb-a77ccc81295f41b72f96db000d1aa44e4dc91254.zip gdb-a77ccc81295f41b72f96db000d1aa44e4dc91254.tar.gz gdb-a77ccc81295f41b72f96db000d1aa44e4dc91254.tar.bz2 | |
arm: Handle undefweak with ST_BRANCH_UNKNOWN
A previous patch made ld fail early on Thumb-only where branch_type is
ST_BRANCH_UNKNOWN.
However, this fails erroneously when the target is undefweak: in that
case the branch should be replaced by a branch to the next instruction
(or nop.w on thumb2). This patch accepts this case and restores the
previous behaviour in such cases.
This was reported by failures in the GCC testsuite, where we fail to
link executables because __deregister_frame_info is undefweak:
(__deregister_frame_info): Unknown destination type (ARM/Thumb) in ...crtbegin.o
crtbegin.o: in function `__do_global_dtors_aux':
crtstuff.c:(.text+0x52): dangerous relocation: unsupported relocation
| -rw-r--r-- | bfd/elf32-arm.c | 7 | ||||
| -rw-r--r-- | ld/testsuite/ld-arm/arm-elf.exp | 1 | ||||
| -rw-r--r-- | ld/testsuite/ld-arm/farcall-missing-type-main-undefweak.s | 10 | ||||
| -rw-r--r-- | ld/testsuite/ld-arm/farcall-missing-type-undefweak.d | 11 |
4 files changed, 28 insertions, 1 deletions
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c index 7441ee2..17df8b3 100644 --- a/bfd/elf32-arm.c +++ b/bfd/elf32-arm.c @@ -10512,7 +10512,12 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto, if (using_thumb_only (globals) && (r_type == R_ARM_THM_CALL || r_type == R_ARM_THM_JUMP24) - && branch_type == ST_BRANCH_UNKNOWN) + && branch_type == ST_BRANCH_UNKNOWN + /* Exception to the rule above: a branch to an undefined weak + symbol is turned into a jump to the next instruction unless a + PLT entry will be created (see below). */ + && !(h && h->root.type == bfd_link_hash_undefweak + && plt_offset == (bfd_vma) -1)) { if (sym_sec != NULL && sym_sec->owner != NULL) diff --git a/ld/testsuite/ld-arm/arm-elf.exp b/ld/testsuite/ld-arm/arm-elf.exp index 5f380e3..7fa4520 100644 --- a/ld/testsuite/ld-arm/arm-elf.exp +++ b/ld/testsuite/ld-arm/arm-elf.exp @@ -1208,6 +1208,7 @@ run_dump_test "attr-merge-wchar-42-nowarn" run_dump_test "attr-merge-wchar-44-nowarn" run_dump_test "farcall-section" run_dump_test "farcall-missing-type" +run_dump_test "farcall-missing-type-undefweak" run_dump_test "attr-merge-unknown-1" run_dump_test "attr-merge-unknown-2" run_dump_test "attr-merge-unknown-2r" diff --git a/ld/testsuite/ld-arm/farcall-missing-type-main-undefweak.s b/ld/testsuite/ld-arm/farcall-missing-type-main-undefweak.s new file mode 100644 index 0000000..cf72722 --- /dev/null +++ b/ld/testsuite/ld-arm/farcall-missing-type-main-undefweak.s @@ -0,0 +1,10 @@ + .thumb + .cpu cortex-m33 + .syntax unified + .global __start + .weak bad + .type __start, function +__start: + push {r4, lr} + bl bad + pop {r4, pc} diff --git a/ld/testsuite/ld-arm/farcall-missing-type-undefweak.d b/ld/testsuite/ld-arm/farcall-missing-type-undefweak.d new file mode 100644 index 0000000..b6e123f --- /dev/null +++ b/ld/testsuite/ld-arm/farcall-missing-type-undefweak.d @@ -0,0 +1,11 @@ +#source: farcall-missing-type-main-undefweak.s +#as: +#ld:-T farcall-missing-type.ld +#objdump: -dr +#... +Disassembly of section .text: + +.* <__start>: + +[0-9a-f]+: .... .... push {r4, lr} + +[0-9a-f]+: .... .... nop.w + +[0-9a-f]+: .... .... pop {r4, pc} |