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authorNelson Chu <nelson@rivosinc.com>2023-03-25 08:41:12 +0800
committerNelson Chu <nelson@rivosinc.com>2023-03-30 07:40:14 +0800
commitb679fb488a8c35e573d50f118a09f72c1f6289de (patch)
tree523872417472d0d54487e0ca668b3260c2b391ca /bfd
parent23068b02d3a6743658110c7662178fdebbe2ac6a (diff)
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RISC-V: Clarify link behaviors of R_RISCV_32/64 relocations with ABS symbol.
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.
Diffstat (limited to 'bfd')
-rw-r--r--bfd/elfnn-riscv.c61
1 files changed, 53 insertions, 8 deletions
diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
index 59e949a..00f034a 100644
--- a/bfd/elfnn-riscv.c
+++ b/bfd/elfnn-riscv.c
@@ -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;