RISC-V: Fix local GOT and reloc size calculation for TLS.

The previous code did not account correctly for two cases:
* A TLS symbol can be referenced with multiple TLS types (although rare),
  in which case it only allocated the maximum slot size among the types,
  instead of the sum.
* TLS relocations are only needed for DLLs, unlike normal symbols which
  requires relocations for all PIE code.

Modify the logic to account for the two cases, so this fixes the redundant
dynamic R_RISCV_NONE in .rela.dyn when using --no-pie for TLS GD and IE.

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

bfd/
    * elfnn-riscv.c (riscv_elf_size_dynamic_sections): Handle relocation
    sizing for TLS and non-TLS symbols differently, with the former
    requiring relocs on DLL while the latter requiring on PIE.
    Allocate GOT slots and relocation slots for each TLS type separately,
    accounting for the possibility of a TLS variable getting referenced by
    multiple symbols.
ld/
    * testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
    * testsuite/ld-riscv-elf/tls*: New testcase for TLS GD and IE, with
    symbols referred by both types and global and local symbols.
This commit is contained in:
Tatsuyuki Ishi
2024-02-21 02:55:48 +09:00
committed by Nelson Chu
parent af514e5f6d
commit 0ac6b8701f
6 changed files with 85 additions and 6 deletions

View File

@@ -1559,13 +1559,28 @@ riscv_elf_size_dynamic_sections (bfd *output_bfd, struct bfd_link_info *info)
if (*local_got > 0) if (*local_got > 0)
{ {
*local_got = s->size; *local_got = s->size;
s->size += RISCV_ELF_WORD_BYTES; if (*local_tls_type & (GOT_TLS_GD | GOT_TLS_IE))
{
if (*local_tls_type & GOT_TLS_GD) if (*local_tls_type & GOT_TLS_GD)
s->size += RISCV_ELF_WORD_BYTES; {
if (bfd_link_pic (info) s->size += 2 * RISCV_ELF_WORD_BYTES;
|| (*local_tls_type & (GOT_TLS_GD | GOT_TLS_IE))) if (bfd_link_dll (info))
srel->size += sizeof (ElfNN_External_Rela); srel->size += sizeof (ElfNN_External_Rela);
} }
if (*local_tls_type & GOT_TLS_IE)
{
s->size += RISCV_ELF_WORD_BYTES;
if (bfd_link_dll (info))
srel->size += sizeof (ElfNN_External_Rela);
}
}
else
{
s->size += RISCV_ELF_WORD_BYTES;
if (bfd_link_pic (info))
srel->size += sizeof (ElfNN_External_Rela);
}
}
else else
*local_got = (bfd_vma) -1; *local_got = (bfd_vma) -1;
} }

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@@ -319,4 +319,12 @@ if [istarget "riscv*-*-*"] {
run_dump_test "pcrel-reloc-rel-pie" run_dump_test "pcrel-reloc-rel-pie"
run_dump_test "pcrel-reloc-abs-nopie" run_dump_test "pcrel-reloc-abs-nopie"
run_dump_test "pcrel-reloc-abs-pie" run_dump_test "pcrel-reloc-abs-pie"
run_ld_link_tests {
{ "Build shared library for TLS runtime"
"-shared" "" "" {tlslib.s}
{} "tlslib.so" }
}
run_dump_test "tls"
run_dump_test "tlsbin"
} }

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@@ -0,0 +1,15 @@
#source: tls.s
#ld: --shared tmpdir/tlslib.so
#readelf: -Wr
Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 5 entries:
+Offset +Info +Type +Symbol's Value +Symbol's Name \+ Addend
[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_DTPMOD64 +0
[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_TPREL64 +4
[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_DTPMOD64 +0+ sg1 \+ 0
[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_DTPREL64 +0+ sg1 \+ 0
[0-9a-f]+ +[0-9a-f]+ R_RISCV_TLS_TPREL64 +0+ sg1 \+ 0
Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entry:
+Offset +Info +Type +Symbol's Value +Symbol's Name \+ Addend
[0-9a-f]+ +[0-9a-f]+ R_RISCV_JUMP_SLOT +0+ __tls_get_addr \+ 0

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@@ -0,0 +1,28 @@
.section .tbss,"awT",@nobits
.global sg1
sg1:
.zero 4
sl1:
.zero 4
.text
.globl _start
.type _start,@function
_start:
/* GD, global var */
la.tls.gd a0,sg1
call __tls_get_addr
/* IE, global var */
la.tls.ie a0,sg1
add a0,a0,tp
/* GD, local var */
la.tls.gd a0,sl1
call __tls_get_addr
/* IE, local var */
la.tls.ie a0,sl1
add a0,a0,tp
ret

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@@ -0,0 +1,7 @@
#source: tls.s
#ld: -no-pie tmpdir/tlslib.so
#readelf: -Wr
Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entry:
+Offset +Info +Type +Symbol's Value +Symbol's Name \+ Addend
[0-9a-f]+ +[0-9a-f]+ R_RISCV_JUMP_SLOT +[0-9a-f]+ __tls_get_addr \+ 0

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@@ -0,0 +1,6 @@
.text
/* Dummy. */
.globl __tls_get_addr
.type __tls_get_addr,@function
__tls_get_addr:
ret