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RISC-V: Clarify link behaviors of R_RISCV_32/64 relocations with ABS symbol.

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There are two improvements, which are all referenced to aarch64,

* R_RISCV_32 with non ABS symbol cannot be used under RV64 when making
  shard objects.

* Don't need dynamic relocation for R_RISCV_32/64 under RV32/RV64 when
  making shared objects, if the referenced symbol is local ABS symbol.

However, considering this link,
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/341

Seems like we should makes all R_RISCV_32/64 relocs with ABS symbol
that don't need any dynamic relocations when making the shared objects.
But anyway, I just sync the current behavior as aarch64 ld, in case
there are any unexpected behaviors happen.

Passed the gcc/binutils regressions in riscv-gnu-toolchain.

bfd/
    * elfnn-riscv.c (riscv_elf_check_relocs): Only allow R_RISCV_32 with ABS
    symbol under RV64.
    (riscv_elf_relocate_section): R_RISCV_32/64 with local ABS symbol under
    RV32/RV64 doesn't need any dynamic relocation when making shared objects.
    I just make the implementations similar to other targets, so that will be
    more easy to mainatain.
ld/
    * testsuite/ld-riscv-elf/data-reloc*: New testcases.
    * testsuite/ld-riscv-elf/ld-riscv-elf.exp: Added new data-reloc* testcases,
    and need to make ifunc-seperate* testcases work for rv32.
    * testsuite/ld-riscv-elf/ifunc-seperate-caller-nonplt.s: Likewise.
    * testsuite/ld-riscv-elf/ifunc-seperate-caller-plt.s: Likewise.
This commit is contained in:
Nelson Chu 2023-03-25 08:41:12 +08:00
parent 23068b02d3
commit b679fb488a
14 changed files with 236 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

61
bfd/elfnn-riscv.c
View File

@ -734,6 +734,7 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
unsigned int r_type;
unsigned int r_symndx;
struct elf_link_hash_entry *h;
bool is_abs_symbol = false;
r_symndx = ELFNN_R_SYM (rel->r_info);
r_type = ELFNN_R_TYPE (rel->r_info);
@ -753,6 +754,8 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
if (isym == NULL)
return false;
is_abs_symbol = isym->st_shndx == SHN_ABS ? true : false;
/* Check relocation against local STT_GNU_IFUNC symbol. */
if (ELF_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
{
@ -778,6 +781,8 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
while (h->root.type == bfd_link_hash_indirect
|| h->root.type == bfd_link_hash_warning)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
is_abs_symbol = bfd_is_abs_symbol (&h->root) ? true : false;
}
if (h != NULL)
@ -879,13 +884,31 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
case R_RISCV_HI20:
if (bfd_link_pic (info))
return bad_static_reloc (abfd, r_type, h);
/* Fall through. */
goto static_reloc;
case R_RISCV_32:
if (ARCH_SIZE > 32
&& bfd_link_pic (info)
&& (sec->flags & SEC_ALLOC) != 0)
{
if (is_abs_symbol)
break;
reloc_howto_type *r_t = riscv_elf_rtype_to_howto (abfd, r_type);
_bfd_error_handler
(_("%pB: relocation %s against non-absolute symbol `%s' can "
"not be used in RVNN when making a shared object"),
abfd, r_t ? r_t->name : _("<unknown>"),
h != NULL ? h->root.root.string : "a local symbol");
bfd_set_error (bfd_error_bad_value);
return false;
}
goto static_reloc;
case R_RISCV_COPY:
case R_RISCV_JUMP_SLOT:
case R_RISCV_RELATIVE:
case R_RISCV_64:
case R_RISCV_32:
/* Fall through. */
static_reloc:
@ -2630,6 +2653,11 @@ riscv_elf_relocate_section (bfd *output_bfd,
break;
case R_RISCV_32:
/* Non ABS symbol should be blocked in check_relocs. */
if (ARCH_SIZE > 32)
break;
/* Fall through. */
case R_RISCV_64:
if ((input_section->flags & SEC_ALLOC) == 0)
break;
@ -2639,7 +2667,6 @@ riscv_elf_relocate_section (bfd *output_bfd,
{
Elf_Internal_Rela outrel;
asection *sreloc;
bool skip_static_relocation, skip_dynamic_relocation;
/* When generating a shared object, these relocations
are copied into the output file to be resolved at run
@ -2648,26 +2675,44 @@ riscv_elf_relocate_section (bfd *output_bfd,
outrel.r_offset =
_bfd_elf_section_offset (output_bfd, info, input_section,
rel->r_offset);
skip_static_relocation = outrel.r_offset != (bfd_vma) -2;
skip_dynamic_relocation = outrel.r_offset >= (bfd_vma) -2;
bool skip = false;
bool relocate = false;
if (outrel.r_offset == (bfd_vma) -1)
skip = true;
else if (outrel.r_offset == (bfd_vma) -2)
{
skip = true;
relocate = true;
}
else if (h != NULL && bfd_is_abs_symbol (&h->root))
{
/* Don't need dynamic reloc when the ABS symbol is
non-dynamic or forced to local. Maybe just use
SYMBOL_REFERENCES_LOCAL to check? */
skip = (h->forced_local || (h->dynindx == -1));
relocate = skip;
}
outrel.r_offset += sec_addr (input_section);
if (skip_dynamic_relocation)
memset (&outrel, 0, sizeof outrel);
if (skip)
memset (&outrel, 0, sizeof outrel); /* R_RISCV_NONE. */
else if (RISCV_COPY_INPUT_RELOC (info, h))
{
/* Maybe just use !SYMBOL_REFERENCES_LOCAL to check? */
outrel.r_info = ELFNN_R_INFO (h->dynindx, r_type);
outrel.r_addend = rel->r_addend;
}
else
{
/* This symbol is local, or marked to become local. */
outrel.r_info = ELFNN_R_INFO (0, R_RISCV_RELATIVE);
outrel.r_addend = relocation + rel->r_addend;
}
sreloc = elf_section_data (input_section)->sreloc;
riscv_elf_append_rela (output_bfd, sreloc, &outrel);
if (skip_static_relocation)
if (!relocate)
continue;
}
break;

21
ld/testsuite/ld-riscv-elf/data-reloc-rv32-pic.d Normal file
View File

@ -0,0 +1,21 @@
#source: data-reloc.s
#as: -march=rv32i -mabi=ilp32 -defsym __abs__=1 -defsym __addr__=1 -defsym __undef__=1
#ld: -m[riscv_choose_ilp32_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared
#objdump: -dR
.*:[ ]+file format .*
Disassembly of section .text:
0+8000 <addr_globl>:
8000: 00000000 .word 0x00000000
8000: R_RISCV_32 addr_globl
0+8004 <addr_local>:
...
8004: R_RISCV_RELATIVE \*ABS\*\+0x8004
8008: R_RISCV_32 abs
800c: 00000200 .word 0x00000200
8010: 00000000 .word 0x00000000
8010: R_RISCV_32 undef

18
ld/testsuite/ld-riscv-elf/data-reloc-rv32-pie.d Normal file
View File

@ -0,0 +1,18 @@
#source: data-reloc.s
#as: -march=rv32i -mabi=ilp32 -defsym __abs__=1 -defsym __addr__=1
#ld: -m[riscv_choose_ilp32_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -pie
#objdump: -dR
.*:[ ]+file format .*
Disassembly of section .text:
0+8000 <addr_globl>:
8000: 00000000 .word 0x00000000
8000: R_RISCV_RELATIVE \*ABS\*\+0x8000
0+8004 <addr_local>:
8004: 00000000 .word 0x00000000
8004: R_RISCV_RELATIVE \*ABS\*\+0x8004
8008: 00000100 .word 0x00000100
800c: 00000200 .word 0x00000200

21
ld/testsuite/ld-riscv-elf/data-reloc-rv32-symbolic.d Normal file
View File

@ -0,0 +1,21 @@
#source: data-reloc.s
#as: -march=rv32i -mabi=ilp32 -defsym __abs__=1 -defsym __addr__=1 -defsym __undef__=1
#ld: -m[riscv_choose_ilp32_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared -Bsymbolic
#objdump: -dR
.*:[ ]+file format .*
Disassembly of section .text:
0+8000 <addr_globl>:
8000: 00000000 .word 0x00000000
8000: R_RISCV_RELATIVE \*ABS\*\+0x8000
0+8004 <addr_local>:
...
8004: R_RISCV_RELATIVE \*ABS\*\+0x8004
8008: R_RISCV_RELATIVE \*ABS\*\+0x100
800c: 00000200 .word 0x00000200
8010: 00000000 .word 0x00000000
8010: R_RISCV_32 undef

13
ld/testsuite/ld-riscv-elf/data-reloc-rv64-abs32-pic.d Normal file
View File

@ -0,0 +1,13 @@
#source: data-reloc.s
#as: -march=rv64i -mabi=lp64 -defsym __abs__=1
#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared
#objdump: -dR
.*:[ ]+file format .*
Disassembly of section .text:
0+8000 <.text>:
8000: 00000100 .word 0x00000100
8004: 00000200 .word 0x00000200

4
ld/testsuite/ld-riscv-elf/data-reloc-rv64-addr32-pic.d Normal file
View File

@ -0,0 +1,4 @@
#source: data-reloc.s
#as: -march=rv64i -mabi=lp64 -defsym __addr__=1
#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 -shared
#error: .*relocation R_RISCV_32 against non-absolute symbol `addr_globl' can not be used in RV64 when making a shared object.*

21
ld/testsuite/ld-riscv-elf/data-reloc-rv64-pic.d Normal file
View File

@ -0,0 +1,21 @@
#source: data-reloc.s
#as: -march=rv64i -mabi=lp64 -defsym __64_bit__=1 -defsym __abs__=1 -defsym __addr__=1 -defsym __undef__=1
#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared
#objdump: -dR
.*:[ ]+file format .*
Disassembly of section .text:
0+8000 <addr_globl>:
...
8000: R_RISCV_64 addr_globl
0+8008 <addr_local>:
...
8008: R_RISCV_RELATIVE \*ABS\*\+0x8008
8010: R_RISCV_64 abs
8018: 00000200 .word 0x00000200
...
8020: R_RISCV_64 undef

21
ld/testsuite/ld-riscv-elf/data-reloc-rv64-pie.d Normal file
View File

@ -0,0 +1,21 @@
#source: data-reloc.s
#as: -march=rv64i -mabi=lp64 -defsym __64_bit__=1 -defsym __abs__=1 -defsym __addr__=1
#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -pie
#objdump: -dR
.*:[ ]+file format .*
Disassembly of section .text:
0+8000 <addr_globl>:
...
8000: R_RISCV_RELATIVE \*ABS\*\+0x8000
0+8008 <addr_local>:
...
8008: R_RISCV_RELATIVE \*ABS\*\+0x8008
8010: 00000100 .word 0x00000100
8014: 00000000 .word 0x00000000
8018: 00000200 .word 0x00000200
801c: 00000000 .word 0x00000000

21
ld/testsuite/ld-riscv-elf/data-reloc-rv64-symbolic.d Normal file
View File

@ -0,0 +1,21 @@
#source: data-reloc.s
#as: -march=rv64i -mabi=lp64 -defsym __64_bit__=1 -defsym __abs__=1 -defsym __addr__=1 -defsym __undef__=1
#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 --defsym abs=0x100 --defsym abs_local=0x200 -shared -Bsymbolic
#objdump: -dR
.*:[ ]+file format .*
Disassembly of section .text:
0+8000 <addr_globl>:
...
8000: R_RISCV_RELATIVE \*ABS\*\+0x8000
0+8008 <addr_local>:
...
8008: R_RISCV_RELATIVE \*ABS\*\+0x8008
8010: R_RISCV_RELATIVE \*ABS\*\+0x100
8018: 00000200 .word 0x00000200
...
8020: R_RISCV_64 undef

4
ld/testsuite/ld-riscv-elf/data-reloc-rv64-undef32-pic.d Normal file
View File

@ -0,0 +1,4 @@
#source: data-reloc.s
#as: -march=rv64i -mabi=lp64 -defsym __undef__=1
#ld: -m[riscv_choose_lp64_emul] -Ttext 0x8000 --defsym _start=0x0 -shared
#error: .*relocation R_RISCV_32 against non-absolute symbol `undef' can not be used in RV64 when making a shared object.*

22
ld/testsuite/ld-riscv-elf/data-reloc.s Normal file
View File

@ -0,0 +1,22 @@
.macro DATA symbol
.ifdef __64_bit__
.quad \symbol
.else
.word \symbol
.endif
.endm
.ifdef __addr__
.globl addr_globl
addr_globl:
DATA addr_globl
addr_local:
DATA addr_local
.endif
.ifdef __abs__
.hidden abs_local
DATA abs
DATA abs_local
.endif
.ifdef __undef__
DATA undef
.endif

2
ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-nonplt.s
View File

@ -20,4 +20,4 @@ main:
.data
foo_addr:
.long foo
.quad foo

2
ld/testsuite/ld-riscv-elf/ifunc-seperate-caller-plt.s
View File

@ -23,4 +23,4 @@ main:
.data
foo_addr:
.long foo
.quad foo

15
ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
View File

@ -217,6 +217,16 @@ if [istarget "riscv*-*-*"] {
run_dump_test "shared-lib-nopic-03"
run_dump_test "shared-lib-nopic-04"
run_dump_test "data-reloc-rv64-pic"
run_dump_test "data-reloc-rv64-pie"
run_dump_test "data-reloc-rv64-symbolic"
run_dump_test "data-reloc-rv32-pic"
run_dump_test "data-reloc-rv32-pie"
run_dump_test "data-reloc-rv32-symbolic"
run_dump_test "data-reloc-rv64-abs32-pic"
run_dump_test "data-reloc-rv64-addr32-pic"
run_dump_test "data-reloc-rv64-undef32-pic"
# IFUNC testcases.
# Check IFUNC by single type relocs.
run_dump_test_ifunc "ifunc-reloc-call-01" rv32 exe
@ -270,6 +280,11 @@ if [istarget "riscv*-*-*"] {
run_dump_test_ifunc "ifunc-plt-got-overwrite" rv64 pie
run_dump_test_ifunc "ifunc-plt-got-overwrite" rv64 pic
# TODO: Make the following tests work under RV32.
if [istarget "riscv32-*-*"] {
return
}
# Setup shared libraries.
run_ld_link_tests {
{ "Build shared library for IFUNC non-PLT caller"