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This commit is contained in:
Rui Ueyama 2021-04-14 23:15:16 +09:00
parent b722bdab3b
commit 4ac4062e33
3 changed files with 70 additions and 55 deletions
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10
main.cc
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@ -256,6 +256,16 @@ static void show_stats(Context<E> &ctx) {
comdat += pair.second.size();
}
Counter num_cies("num_cies", ctx.eh_frame->cies.size());
Counter num_unique_cies("num_unique_cies");
Counter num_fdes("num_fdes");
for (CieRecord<E> *cie : ctx.eh_frame->cies) {
if (cie->is_leader)
num_unique_cies++;
num_fdes += cie->fdes.size();
}
Counter num_input_sections("input_sections");
for (ObjectFile<E> *file : ctx.objs)
num_input_sections += file->sections.size();

3
mold.h
View File

@ -197,8 +197,9 @@ struct CieRecord {
// For .eh_frame
u32 offset = -1;
u32 leader_offset = -1;
u32 fde_offset = -1;
u32 fde_size = -1;
bool is_leader = false;
// For .eh_frame_hdr
u32 num_fdes = 0;

112
output_chunks.cc
View File

@ -1149,10 +1149,7 @@ void EhFrameSection<E>::construct(Context<E> &ctx) {
// Remove dead FDEs and assign them offsets within their corresponding
// CIE group.
tbb::parallel_for((i64)0, (i64)ctx.objs.size(), [&](i64 i) {
ObjectFile<E> *file = ctx.objs[i];
i64 count = 0;
for (CieRecord<E> &cie : file->cies) {
for (CieRecord<E> &cie : ctx.objs[i]->cies) {
i64 offset = 0;
for (FdeRecord<E> &fde : cie.fdes) {
if (!fde.is_alive)
@ -1171,32 +1168,41 @@ void EhFrameSection<E>::construct(Context<E> &ctx) {
for (CieRecord<E> &cie : file->cies)
cies.push_back(&cie);
// Uniquify CIEs and assign offsets to them.
std::vector<CieRecord<E> *> leaders;
auto find_leader = [&](CieRecord<E> *cie) -> CieRecord<E> * {
for (CieRecord<E> *leader : leaders)
if (cie->contents == leader->contents && cie->rels == leader->rels)
return leader;
return nullptr;
};
i64 offset = 0;
for (CieRecord<E> *cie : cies) {
if (CieRecord<E> *leader = find_leader(cie)) {
cie->offset = leader->offset;
} else {
cie->offset = offset;
cie->is_leader = true;
offset += cie->contents.size();
leaders.push_back(cie);
}
}
// Assign offsets to FDEs.
for (CieRecord<E> *cie : cies) {
cie->fde_offset = offset;
offset += cie->fde_size;
}
this->shdr.sh_size = offset;
// Record the total number of FDEs for .eh_frame_hdr.
for (CieRecord<E> *cie : cies) {
cie->fde_idx = num_fdes;
num_fdes += cie->num_fdes;
}
// Assign offsets within the output section to CIEs.
auto should_merge = [](CieRecord<E> &a, CieRecord<E> &b) {
return a.contents == b.contents && a.rels == b.rels;
};
i64 offset = 0;
for (i64 i = 0; i < cies.size(); i++) {
CieRecord<E> &cie = *cies[i];
cie.offset = offset;
if (i == 0 || !should_merge(cie, *cies[i - 1])) {
cie.leader_offset = offset;
offset += cie.contents.size() + cie.fde_size;
} else {
cie.leader_offset = cies[i - 1]->leader_offset;
offset += cie.fde_size;
}
}
this->shdr.sh_size = offset;
if (ctx.eh_frame_hdr)
ctx.eh_frame_hdr->shdr.sh_size =
ctx.eh_frame_hdr->HEADER_SIZE + num_fdes * 8;
@ -1206,6 +1212,20 @@ template <typename E>
void EhFrameSection<E>::copy_buf(Context<E> &ctx) {
u8 *base = ctx.buf + this->shdr.sh_offset;
// Copy CIEs.
for (CieRecord<E> *cie : cies) {
if (!cie->is_leader)
continue;
memcpy(base + cie->offset, cie->contents.data(), cie->contents.size());
for (EhReloc<E> &rel : cie->rels) {
u64 loc = cie->offset + rel.offset;
u64 val = rel.sym.get_addr(ctx) + rel.addend;
apply_reloc(ctx, rel, loc, val);
}
}
u8 *hdr_base = nullptr;
if (ctx.eh_frame_hdr)
hdr_base = ctx.buf + ctx.eh_frame_hdr->shdr.sh_offset;
@ -1215,35 +1235,20 @@ void EhFrameSection<E>::copy_buf(Context<E> &ctx) {
i32 fde_addr;
};
// Copy CIEs and FDEs.
// Copy FDEs.
tbb::parallel_for_each(cies, [&](CieRecord<E> *cie) {
i64 cie_size = 0;
Entry *entry = nullptr;
if (ctx.eh_frame_hdr)
entry = (Entry *)(hdr_base + ctx.eh_frame_hdr->HEADER_SIZE) +
cie->fde_idx;
// Copy a CIE.
if (cie->offset == cie->leader_offset) {
memcpy(base + cie->offset, cie->contents.data(), cie->contents.size());
cie_size = cie->contents.size();
for (EhReloc<E> &rel : cie->rels) {
u64 loc = cie->offset + rel.offset;
u64 val = rel.sym.get_addr(ctx) + rel.addend;
apply_reloc(ctx, rel, loc, val);
}
}
// Copy FDEs.
for (FdeRecord<E> &fde : cie->fdes) {
if (fde.offset == -1)
continue;
i64 fde_off = cie->offset + cie_size + fde.offset;
i64 fde_off = cie->fde_offset + fde.offset;
memcpy(base + fde_off, fde.contents.data(), fde.contents.size());
*(u32 *)(base + fde_off + 4) = fde_off + 4 - cie->leader_offset;
*(u32 *)(base + fde_off + 4) = fde_off + 4 - cie->offset;
for (i64 i = 0; i < fde.rels.size(); i++) {
EhReloc<E> &rel = fde.rels[i];
@ -1299,24 +1304,23 @@ u64 EhFrameSection<E>::get_addr(Context<E> &ctx, const Symbol<E> &sym) {
};
for (CieRecord<E> &cie : isec.file.cies) {
u64 offset = 0;
if (cie.offset == cie.leader_offset) {
if (contains(cie.contents, section_begin + offset)) {
u64 cie_addr = this->shdr.sh_addr + cie.offset;
u64 addend = sym.value - offset;
return cie_addr + addend;
}
offset += cie.contents.size();
if (contains(cie.contents, section_begin + sym.value)) {
u64 cie_addr = this->shdr.sh_addr + cie.offset;
u64 addend = cie.contents.data() - section_begin - sym.value;
return cie_addr + addend;
}
}
for (CieRecord<E> &cie : isec.file.cies) {
i64 offset = cie.fde_offset;
for (FdeRecord<E> &fde : cie.fdes) {
if (contains(fde.contents, section_begin + offset)) {
if (contains(fde.contents, section_begin + sym.value)) {
if (!fde.is_alive)
return 0;
u64 fde_addr = this->shdr.sh_addr + cie.offset + offset;
u64 addend = sym.value - offset;
u64 fde_addr = this->shdr.sh_addr + offset;
u64 addend = fde.contents.data() - section_begin - sym.value;
return fde_addr + addend;
}
offset += fde.contents.size();