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Refactor

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This commit is contained in:
Rui Ueyama 2023-03-28 16:27:30 +08:00
parent 46288758a0
commit 0f1b828e6a
1 changed files with 58 additions and 42 deletions
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100
elf/arch-riscv.cc
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@ -309,6 +309,27 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
<< lo << ", " << hi << ")";
};
auto find_paired_reloc = [&] {
Symbol<E> &sym = *file.symbols[rels[i].r_sym];
assert(sym.get_input_section() == this);
if (sym.value < r_offset) {
for (i64 j = i - 1; j >= 0; j--)
if (rels[j].r_type != R_RISCV_NONE &&
rels[j].r_type != R_RISCV_RELAX &&
sym.value == rels[j].r_offset - get_r_delta(j))
return j;
} else {
for (i64 j = i + 1; j < rels.size(); j++)
if (rels[j].r_type != R_RISCV_NONE &&
rels[j].r_type != R_RISCV_RELAX &&
sym.value == rels[j].r_offset - get_r_delta(j))
return j;
}
Fatal(ctx) << *this << ": paired relocation is missing: " << i;
};
u64 S = sym.get_addr(ctx);
u64 A = rel.r_addend;
u64 P = get_addr() + r_offset;
@ -364,21 +385,52 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
break;
}
case R_RISCV_GOT_HI20:
*(ul32 *)loc = G + GOT + A - P;
write_utype(loc, G + GOT + A - P);
break;
case R_RISCV_TLS_GOT_HI20:
*(ul32 *)loc = sym.get_gottp_addr(ctx) + A - P;
write_utype(loc, sym.get_gottp_addr(ctx) + A - P);
break;
case R_RISCV_TLS_GD_HI20:
*(ul32 *)loc = sym.get_tlsgd_addr(ctx) + A - P;
write_utype(loc, sym.get_tlsgd_addr(ctx) + A - P);
break;
case R_RISCV_PCREL_HI20:
*(ul32 *)loc = S + A - P;
write_utype(loc, S + A - P);
break;
case R_RISCV_PCREL_LO12_I:
case R_RISCV_PCREL_LO12_S:
// These relocations are handled in the next loop.
case R_RISCV_PCREL_LO12_S: {
i64 idx2 = find_paired_reloc();
const ElfRel<E> &rel2 = rels[idx2];
Symbol<E> &sym2 = *file.symbols[rel2.r_sym];
u64 S = sym2.get_addr(ctx);
u64 A = rel2.r_addend;
u64 P = get_addr() + rel2.r_offset - get_r_delta(idx2);
u64 G = sym2.get_got_idx(ctx) * sizeof(Word<E>);
u64 val;
switch (rel2.r_type) {
case R_RISCV_GOT_HI20:
val = G + GOT + A - P;
break;
case R_RISCV_TLS_GOT_HI20:
val = sym2.get_gottp_addr(ctx) + A - P;
break;
case R_RISCV_TLS_GD_HI20:
val = sym2.get_tlsgd_addr(ctx) + A - P;
break;
case R_RISCV_PCREL_HI20:
val = S + A - P;
break;
default:
Fatal(ctx) << "bad paired relocation type: " << rel2;
}
if (rel.r_type == R_RISCV_PCREL_LO12_I)
write_itype(loc, val);
else
write_stype(loc, val);
break;
}
case R_RISCV_HI20:
assert(removed_bytes == 0 || removed_bytes == 4);
if (removed_bytes == 0) {
@ -497,42 +549,6 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
unreachable();
}
}
// Handle PC-relative LO12 relocations. In the above loop, pcrel HI20
// relocations overwrote instructions with full 32-bit values to allow
// their corresponding pcrel LO12 relocations to read their values.
for (i64 i = 0; i < rels.size(); i++) {
switch (rels[i].r_type) {
case R_RISCV_PCREL_LO12_I:
case R_RISCV_PCREL_LO12_S: {
Symbol<E> &sym = *file.symbols[rels[i].r_sym];
assert(sym.get_input_section() == this);
u8 *loc = base + rels[i].r_offset - get_r_delta(i);
u32 val = *(ul32 *)(base + sym.value);
if (rels[i].r_type == R_RISCV_PCREL_LO12_I)
write_itype(loc, val);
else
write_stype(loc, val);
}
}
}
// Restore the original instructions pcrel HI20 relocations overwrote.
for (i64 i = 0; i < rels.size(); i++) {
switch (rels[i].r_type) {
case R_RISCV_GOT_HI20:
case R_RISCV_PCREL_HI20:
case R_RISCV_TLS_GOT_HI20:
case R_RISCV_TLS_GD_HI20: {
u8 *loc = base + rels[i].r_offset - get_r_delta(i);
u32 val = *(ul32 *)loc;
memcpy(loc, contents.data() + rels[i].r_offset, 4);
write_utype(loc, val);
}
}
}
}
template <typename E>