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3
.github/workflows/ci.yml
vendored
3
.github/workflows/ci.yml
vendored
@ -13,7 +13,6 @@ jobs:
|
||||
target:
|
||||
# Disable PCH for the default configuration. This prevents relying on implicit includes.
|
||||
- '-DCMAKE_DISABLE_PRECOMPILE_HEADERS=On'
|
||||
- '-DMOLD_USE_ASAN=On'
|
||||
- '-DMOLD_USE_TSAN=On'
|
||||
runs-on: ubuntu-20.04
|
||||
steps:
|
||||
@ -110,7 +109,7 @@ jobs:
|
||||
!build/CMakeFiles
|
||||
|
||||
build-macos:
|
||||
runs-on: macos-11
|
||||
runs-on: macos-12
|
||||
strategy:
|
||||
matrix:
|
||||
target:
|
||||
|
@ -328,7 +328,6 @@ list(APPEND MOLD_ELF_TEMPLATE_FILES
|
||||
elf/output-chunks.cc
|
||||
elf/passes.cc
|
||||
elf/relocatable.cc
|
||||
elf/subprocess.cc
|
||||
elf/thunks.cc
|
||||
elf/tls.cc
|
||||
)
|
||||
@ -339,6 +338,12 @@ else()
|
||||
list(APPEND MOLD_ELF_TEMPLATE_FILES elf/lto-unix.cc)
|
||||
endif()
|
||||
|
||||
if(WIN32)
|
||||
list(APPEND MOLD_ELF_TEMPLATE_FILES elf/subprocess-win32.cc)
|
||||
else()
|
||||
list(APPEND MOLD_ELF_TEMPLATE_FILES elf/subprocess-unix.cc)
|
||||
endif()
|
||||
|
||||
function(mold_instantiate_templates SOURCE TARGET)
|
||||
set(PATH ${CMAKE_BINARY_DIR}/${SOURCE}.${TARGET}.cc)
|
||||
if(NOT EXISTS ${PATH})
|
||||
|
@ -88,9 +88,9 @@ Problem: A statically-linked "hello world" program crashes after
|
||||
reading a thread-local variable.
|
||||
|
||||
Investigation: Thread-local variables are very different from other
|
||||
types of varaibles because there may be more than one instance of the
|
||||
types of variables because there may be more than one instance of the
|
||||
same variable in memory. Each thread has its copy of thread-local
|
||||
varaibles. `%fs` segment register points the end of the variable area
|
||||
variables. `%fs` segment register points the end of the variable area
|
||||
for the current thread, and the variables are accessed as an offset
|
||||
from `%fs`.
|
||||
|
||||
|
@ -677,104 +677,6 @@ void ObjectFile<E>::sort_relocations(Context<E> &ctx) {
|
||||
}
|
||||
}
|
||||
|
||||
static size_t find_null(std::string_view data, i64 pos, i64 entsize) {
|
||||
if (entsize == 1)
|
||||
return data.find('\0', pos);
|
||||
|
||||
for (; pos <= data.size() - entsize; pos += entsize)
|
||||
if (data.substr(pos, entsize).find_first_not_of('\0') == data.npos)
|
||||
return pos;
|
||||
|
||||
return data.npos;
|
||||
}
|
||||
|
||||
// Mergeable sections (sections with SHF_MERGE bit) typically contain
|
||||
// string literals. Linker is expected to split the section contents
|
||||
// into null-terminated strings, merge them with mergeable strings
|
||||
// from other object files, and emit uniquified strings to an output
|
||||
// file.
|
||||
//
|
||||
// This mechanism reduces the size of an output file. If two source
|
||||
// files happen to contain the same string literal, the output will
|
||||
// contain only a single copy of it.
|
||||
//
|
||||
// It is less common than string literals, but mergeable sections can
|
||||
// contain fixed-sized read-only records too.
|
||||
//
|
||||
// This function splits the section contents into small pieces that we
|
||||
// call "section fragments". Section fragment is a unit of merging.
|
||||
//
|
||||
// We do not support mergeable sections that have relocations.
|
||||
template <typename E>
|
||||
static std::unique_ptr<MergeableSection<E>>
|
||||
split_section(Context<E> &ctx, InputSection<E> &sec) {
|
||||
if (!sec.is_alive || sec.relsec_idx != -1 || sec.sh_size == 0)
|
||||
return nullptr;
|
||||
|
||||
const ElfShdr<E> &shdr = sec.shdr();
|
||||
if (!(shdr.sh_flags & SHF_MERGE))
|
||||
return nullptr;
|
||||
|
||||
i64 entsize = shdr.sh_entsize;
|
||||
if (entsize == 0)
|
||||
entsize = (shdr.sh_flags & SHF_STRINGS) ? 1 : (int)shdr.sh_addralign;
|
||||
|
||||
if (entsize == 0)
|
||||
return nullptr;
|
||||
|
||||
i64 addralign = shdr.sh_addralign;
|
||||
if (addralign == 0)
|
||||
addralign = 1;
|
||||
|
||||
std::unique_ptr<MergeableSection<E>> m(new MergeableSection<E>);
|
||||
m->parent = MergedSection<E>::get_instance(ctx, sec.name(), shdr.sh_type,
|
||||
shdr.sh_flags, entsize, addralign);
|
||||
m->p2align = sec.p2align;
|
||||
|
||||
// If thes section contents are compressed, uncompress them.
|
||||
sec.uncompress(ctx);
|
||||
|
||||
std::string_view data = sec.contents;
|
||||
m->contents = sec.contents;
|
||||
|
||||
if (data.size() > UINT32_MAX)
|
||||
Fatal(ctx) << sec << ": mergeable section too large";
|
||||
|
||||
// Split sections
|
||||
if (shdr.sh_flags & SHF_STRINGS) {
|
||||
for (i64 pos = 0; pos < data.size();) {
|
||||
m->frag_offsets.push_back(pos);
|
||||
size_t end = find_null(data, pos, entsize);
|
||||
if (end == data.npos)
|
||||
Fatal(ctx) << sec << ": string is not null terminated";
|
||||
pos = end + entsize;
|
||||
}
|
||||
} else {
|
||||
if (data.size() % entsize)
|
||||
Fatal(ctx) << sec << ": section size is not multiple of sh_entsize";
|
||||
m->frag_offsets.reserve(data.size() / entsize);
|
||||
|
||||
for (i64 pos = 0; pos < data.size(); pos += entsize)
|
||||
m->frag_offsets.push_back(pos);
|
||||
}
|
||||
|
||||
// Compute hashes for section pieces
|
||||
HyperLogLog estimator;
|
||||
m->hashes.reserve(m->frag_offsets.size());
|
||||
|
||||
for (i64 i = 0; i < m->frag_offsets.size(); i++) {
|
||||
u64 hash = hash_string(m->get_contents(i));
|
||||
m->hashes.push_back(hash);
|
||||
estimator.insert(hash);
|
||||
}
|
||||
|
||||
m->parent->estimator.merge(estimator);
|
||||
|
||||
static Counter counter("string_fragments");
|
||||
counter += m->frag_offsets.size();
|
||||
return m;
|
||||
}
|
||||
|
||||
// Usually a section is an atomic unit of inclusion or exclusion.
|
||||
// Linker doesn't care about its contents. However, if a section is a
|
||||
// mergeable section (a section with SHF_MERGE bit set), the linker is
|
||||
@ -818,34 +720,45 @@ split_section(Context<E> &ctx, InputSection<E> &sec) {
|
||||
// section piece, the section piece is attached to the symbol.
|
||||
template <typename E>
|
||||
void ObjectFile<E>::initialize_mergeable_sections(Context<E> &ctx) {
|
||||
mergeable_sections.resize(sections.size());
|
||||
// Convert InputSections to MergeableSections
|
||||
for (i64 i = 0; i < this->sections.size(); i++) {
|
||||
InputSection<E> *isec = this->sections[i].get();
|
||||
if (!isec || isec->sh_size == 0 || isec->relsec_idx != -1)
|
||||
continue;
|
||||
|
||||
for (i64 i = 0; i < sections.size(); i++) {
|
||||
if (std::unique_ptr<InputSection<E>> &isec = sections[i]) {
|
||||
if (std::unique_ptr<MergeableSection<E>> m = split_section(ctx, *isec)) {
|
||||
mergeable_sections[i] = std::move(m);
|
||||
isec->is_alive = false;
|
||||
}
|
||||
MergedSection<E> *parent =
|
||||
MergedSection<E>::get_instance(ctx, isec->name(), isec->shdr());
|
||||
|
||||
if (parent) {
|
||||
this->mergeable_sections[i] =
|
||||
std::make_unique<MergeableSection<E>>(ctx, *parent, this->sections[i]);
|
||||
this->sections[i] = nullptr;
|
||||
}
|
||||
}
|
||||
|
||||
// Split section contents
|
||||
for (std::unique_ptr<MergeableSection<E>> &sec : mergeable_sections)
|
||||
if (sec)
|
||||
sec->split_contents(ctx);
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
void ObjectFile<E>::resolve_section_pieces(Context<E> &ctx) {
|
||||
for (std::unique_ptr<MergeableSection<E>> &m : mergeable_sections) {
|
||||
if (m) {
|
||||
m->fragments.reserve(m->frag_offsets.size());
|
||||
if (!m)
|
||||
continue;
|
||||
|
||||
for (i64 i = 0; i < m->frag_offsets.size(); i++) {
|
||||
SectionFragment<E> *frag =
|
||||
m->parent->insert(ctx, m->get_contents(i), m->hashes[i], m->p2align);
|
||||
m->fragments.push_back(frag);
|
||||
}
|
||||
m->fragments.reserve(m->frag_offsets.size());
|
||||
|
||||
// Reclaim memory as we'll never use this vector again
|
||||
m->hashes.clear();
|
||||
m->hashes.shrink_to_fit();
|
||||
for (i64 i = 0; i < m->frag_offsets.size(); i++) {
|
||||
SectionFragment<E> *frag =
|
||||
m->parent.insert(ctx, m->get_contents(i), m->hashes[i], m->p2align);
|
||||
m->fragments.push_back(frag);
|
||||
}
|
||||
|
||||
// Reclaim memory as we'll never use this vector again
|
||||
m->hashes.clear();
|
||||
m->hashes.shrink_to_fit();
|
||||
}
|
||||
|
||||
// Attach section pieces to symbols.
|
||||
@ -872,24 +785,25 @@ void ObjectFile<E>::resolve_section_pieces(Context<E> &ctx) {
|
||||
}
|
||||
|
||||
// Compute the size of frag_syms.
|
||||
i64 nfrag_syms = 0;
|
||||
std::vector<InputSection<E> *> vec;
|
||||
for (std::unique_ptr<InputSection<E>> &isec : sections)
|
||||
if (isec && isec->is_alive && (isec->shdr().sh_flags & SHF_ALLOC))
|
||||
for (ElfRel<E> &r : isec->get_rels(ctx))
|
||||
if (const ElfSym<E> &esym = this->elf_syms[r.r_sym];
|
||||
esym.st_type == STT_SECTION && mergeable_sections[get_shndx(esym)])
|
||||
nfrag_syms++;
|
||||
vec.push_back(isec.get());
|
||||
|
||||
i64 nfrag_syms = 0;
|
||||
for (InputSection<E> *isec : vec)
|
||||
for (ElfRel<E> &r : isec->get_rels(ctx))
|
||||
if (const ElfSym<E> &esym = this->elf_syms[r.r_sym];
|
||||
esym.st_type == STT_SECTION && mergeable_sections[get_shndx(esym)])
|
||||
nfrag_syms++;
|
||||
|
||||
this->frag_syms.resize(nfrag_syms);
|
||||
|
||||
// For each relocation referring a mergeable section symbol, we create
|
||||
// a new dummy non-section symbol and redirect the relocation to the
|
||||
// newly-created symbol.
|
||||
// For each relocation referring to a mergeable section symbol, we
|
||||
// create a new dummy non-section symbol and redirect the relocation
|
||||
// to the newly created symbol.
|
||||
i64 idx = 0;
|
||||
for (std::unique_ptr<InputSection<E>> &isec : sections) {
|
||||
if (!isec || !isec->is_alive || !(isec->shdr().sh_flags & SHF_ALLOC))
|
||||
continue;
|
||||
|
||||
for (InputSection<E> *isec : vec) {
|
||||
for (ElfRel<E> &r : isec->get_rels(ctx)) {
|
||||
const ElfSym<E> &esym = this->elf_syms[r.r_sym];
|
||||
if (esym.st_type != STT_SECTION)
|
||||
@ -929,6 +843,8 @@ void ObjectFile<E>::resolve_section_pieces(Context<E> &ctx) {
|
||||
template <typename E>
|
||||
void ObjectFile<E>::parse(Context<E> &ctx) {
|
||||
sections.resize(this->elf_sections.size());
|
||||
mergeable_sections.resize(sections.size());
|
||||
|
||||
symtab_sec = this->find_section(SHT_SYMTAB);
|
||||
|
||||
if (symtab_sec) {
|
||||
|
@ -552,9 +552,88 @@ bool InputSection<E>::record_undef_error(Context<E> &ctx, const ElfRel<E> &rel)
|
||||
return false;
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
MergeableSection<E>::MergeableSection(Context<E> &ctx, MergedSection<E> &parent,
|
||||
std::unique_ptr<InputSection<E>> &isec)
|
||||
: parent(parent), section(std::move(isec)), p2align(section->p2align) {
|
||||
section->uncompress(ctx);
|
||||
}
|
||||
|
||||
static size_t find_null(std::string_view data, i64 pos, i64 entsize) {
|
||||
if (entsize == 1)
|
||||
return data.find('\0', pos);
|
||||
|
||||
for (; pos <= data.size() - entsize; pos += entsize)
|
||||
if (data.substr(pos, entsize).find_first_not_of('\0') == data.npos)
|
||||
return pos;
|
||||
|
||||
return data.npos;
|
||||
}
|
||||
|
||||
// Mergeable sections (sections with SHF_MERGE bit) typically contain
|
||||
// string literals. Linker is expected to split the section contents
|
||||
// into null-terminated strings, merge them with mergeable strings
|
||||
// from other object files, and emit uniquified strings to an output
|
||||
// file.
|
||||
//
|
||||
// This mechanism reduces the size of an output file. If two source
|
||||
// files happen to contain the same string literal, the output will
|
||||
// contain only a single copy of it.
|
||||
//
|
||||
// It is less common than string literals, but mergeable sections can
|
||||
// contain fixed-sized read-only records too.
|
||||
//
|
||||
// This function splits the section contents into small pieces that we
|
||||
// call "section fragments". Section fragment is a unit of merging.
|
||||
//
|
||||
// We do not support mergeable sections that have relocations.
|
||||
template <typename E>
|
||||
void MergeableSection<E>::split_contents(Context<E> &ctx) {
|
||||
std::string_view data = section->contents;
|
||||
if (data.size() > UINT32_MAX)
|
||||
Fatal(ctx) << *section
|
||||
<< ": mergeable section too large";
|
||||
|
||||
i64 entsize = parent.shdr.sh_entsize;
|
||||
|
||||
// Split sections
|
||||
if (parent.shdr.sh_flags & SHF_STRINGS) {
|
||||
for (i64 pos = 0; pos < data.size();) {
|
||||
frag_offsets.push_back(pos);
|
||||
size_t end = find_null(data, pos, entsize);
|
||||
if (end == data.npos)
|
||||
Fatal(ctx) << *section << ": string is not null terminated";
|
||||
pos = end + entsize;
|
||||
}
|
||||
} else {
|
||||
if (data.size() % entsize)
|
||||
Fatal(ctx) << *section << ": section size is not multiple of sh_entsize";
|
||||
frag_offsets.reserve(data.size() / entsize);
|
||||
|
||||
for (i64 pos = 0; pos < data.size(); pos += entsize)
|
||||
frag_offsets.push_back(pos);
|
||||
}
|
||||
|
||||
// Compute hashes for section pieces
|
||||
HyperLogLog estimator;
|
||||
hashes.reserve(frag_offsets.size());
|
||||
|
||||
for (i64 i = 0; i < frag_offsets.size(); i++) {
|
||||
u64 hash = hash_string(get_contents(i));
|
||||
hashes.push_back(hash);
|
||||
estimator.insert(hash);
|
||||
}
|
||||
|
||||
parent.estimator.merge(estimator);
|
||||
|
||||
static Counter counter("string_fragments");
|
||||
counter += frag_offsets.size();
|
||||
}
|
||||
|
||||
using E = MOLD_TARGET;
|
||||
|
||||
template bool cie_equals(const CieRecord<E> &, const CieRecord<E> &);
|
||||
template class InputSection<E>;
|
||||
template class MergeableSection<E>;
|
||||
|
||||
} // namespace mold::elf
|
||||
|
@ -567,11 +567,7 @@ static ElfSym<E> to_elf_sym(PluginSymbol &psym) {
|
||||
// Returns false if it's GCC.
|
||||
template <typename E>
|
||||
static bool is_llvm(Context<E> &ctx) {
|
||||
#ifdef __MINGW32__
|
||||
return ctx.arg.plugin.ends_with("LLVMgold.dll");
|
||||
#else
|
||||
return ctx.arg.plugin.ends_with("LLVMgold.so");
|
||||
#endif
|
||||
return ctx.arg.plugin.find("LLVMgold.") != ctx.arg.plugin.npos;
|
||||
}
|
||||
|
||||
// Returns true if a given linker plugin supports the get_symbols_v3 API.
|
||||
|
31
elf/main.cc
31
elf/main.cc
@ -345,12 +345,8 @@ int elf_main(int argc, char **argv) {
|
||||
Context<E> ctx;
|
||||
|
||||
// Process -run option first. process_run_subcommand() does not return.
|
||||
if (argc >= 2 && (argv[1] == "-run"sv || argv[1] == "--run"sv)) {
|
||||
#if defined(_WIN32) || defined(__APPLE__)
|
||||
Fatal(ctx) << "-run is supported only on Unix";
|
||||
#endif
|
||||
if (argc >= 2 && (argv[1] == "-run"sv || argv[1] == "--run"sv))
|
||||
process_run_subcommand(ctx, argc, argv);
|
||||
}
|
||||
|
||||
// Parse non-positional command line options
|
||||
ctx.cmdline_args = expand_response_files(ctx, argv);
|
||||
@ -375,12 +371,8 @@ int elf_main(int argc, char **argv) {
|
||||
<< ": " << errno_string();
|
||||
|
||||
// Fork a subprocess unless --no-fork is given.
|
||||
std::function<void()> on_complete;
|
||||
|
||||
#if !defined(_WIN32) && !defined(__APPLE__)
|
||||
if (ctx.arg.fork)
|
||||
on_complete = fork_child();
|
||||
#endif
|
||||
fork_child();
|
||||
|
||||
acquire_global_lock();
|
||||
|
||||
@ -664,8 +656,13 @@ int elf_main(int argc, char **argv) {
|
||||
// so we sort them.
|
||||
ctx.reldyn->sort(ctx);
|
||||
|
||||
// Zero-clear paddings between sections
|
||||
clear_padding(ctx);
|
||||
// .note.gnu.build-id section contains a cryptographic hash of the
|
||||
// entire output file. Now that we wrote everything except build-id,
|
||||
// we can compute it.
|
||||
if (ctx.buildid) {
|
||||
compute_build_id(ctx);
|
||||
ctx.buildid->copy_buf(ctx);
|
||||
}
|
||||
|
||||
// .gdb_index's contents cannot be constructed before applying
|
||||
// relocations to other debug sections. We have relocated debug
|
||||
@ -673,12 +670,6 @@ int elf_main(int argc, char **argv) {
|
||||
if (ctx.gdb_index)
|
||||
write_gdb_index(ctx);
|
||||
|
||||
// .note.gnu.build-id section contains a cryptographic hash of the
|
||||
// entire output file. Now that we wrote everything except build-id,
|
||||
// we can compute it.
|
||||
if (ctx.buildid)
|
||||
ctx.buildid->write_buildid(ctx);
|
||||
|
||||
t_copy.stop();
|
||||
ctx.checkpoint();
|
||||
|
||||
@ -707,8 +698,8 @@ int elf_main(int argc, char **argv) {
|
||||
std::cout << std::flush;
|
||||
std::cerr << std::flush;
|
||||
|
||||
if (on_complete)
|
||||
on_complete();
|
||||
if (ctx.arg.fork)
|
||||
notify_parent();
|
||||
|
||||
release_global_lock();
|
||||
|
||||
|
40
elf/mold.h
40
elf/mold.h
@ -47,6 +47,7 @@ template <typename E> class Symbol;
|
||||
template <typename E> struct CieRecord;
|
||||
template <typename E> struct Context;
|
||||
template <typename E> struct FdeRecord;
|
||||
template <typename E> class MergeableSection;
|
||||
template <typename E> class RelocSection;
|
||||
|
||||
template <typename E>
|
||||
@ -799,8 +800,7 @@ template <typename E>
|
||||
class MergedSection : public Chunk<E> {
|
||||
public:
|
||||
static MergedSection<E> *
|
||||
get_instance(Context<E> &ctx, std::string_view name, i64 type, i64 flags,
|
||||
i64 entsize, i64 addralign);
|
||||
get_instance(Context<E> &ctx, std::string_view name, const ElfShdr<E> &shdr);
|
||||
|
||||
SectionFragment<E> *insert(Context<E> &ctx, std::string_view data,
|
||||
u64 hash, i64 p2align);
|
||||
@ -949,9 +949,8 @@ public:
|
||||
|
||||
void update_shdr(Context<E> &ctx) override;
|
||||
void copy_buf(Context<E> &ctx) override;
|
||||
void write_buildid(Context<E> &ctx);
|
||||
|
||||
static constexpr i64 HEADER_SIZE = 16;
|
||||
std::vector<u8> contents;
|
||||
};
|
||||
|
||||
template <typename E>
|
||||
@ -1090,12 +1089,17 @@ struct ComdatGroupRef {
|
||||
};
|
||||
|
||||
template <typename E>
|
||||
struct MergeableSection {
|
||||
class MergeableSection {
|
||||
public:
|
||||
MergeableSection(Context<E> &ctx, MergedSection<E> &parent,
|
||||
std::unique_ptr<InputSection<E>> &isec);
|
||||
|
||||
void split_contents(Context<E> &ctx);
|
||||
std::pair<SectionFragment<E> *, i64> get_fragment(i64 offset);
|
||||
std::string_view get_contents(i64 idx);
|
||||
|
||||
MergedSection<E> *parent;
|
||||
std::string_view contents;
|
||||
MergedSection<E> &parent;
|
||||
std::unique_ptr<InputSection<E>> section;
|
||||
std::vector<u32> frag_offsets;
|
||||
std::vector<u32> hashes;
|
||||
std::vector<SectionFragment<E> *> fragments;
|
||||
@ -1368,7 +1372,8 @@ void print_map(Context<E> &ctx);
|
||||
// subprocess.cc
|
||||
//
|
||||
|
||||
std::function<void()> fork_child();
|
||||
void fork_child();
|
||||
void notify_parent();
|
||||
|
||||
template <typename E>
|
||||
[[noreturn]]
|
||||
@ -1426,11 +1431,11 @@ template <typename E> void apply_version_script(Context<E> &);
|
||||
template <typename E> void parse_symbol_version(Context<E> &);
|
||||
template <typename E> void compute_import_export(Context<E> &);
|
||||
template <typename E> void compute_address_significance(Context<E> &);
|
||||
template <typename E> void clear_padding(Context<E> &);
|
||||
template <typename E> void compute_section_headers(Context<E> &);
|
||||
template <typename E> i64 set_osec_offsets(Context<E> &);
|
||||
template <typename E> void fix_synthetic_symbols(Context<E> &);
|
||||
template <typename E> i64 compress_debug_sections(Context<E> &);
|
||||
template <typename E> void compute_build_id(Context<E> &);
|
||||
template <typename E> void write_dependency_file(Context<E> &);
|
||||
template <typename E> void show_stats(Context<E> &);
|
||||
|
||||
@ -1565,7 +1570,18 @@ private:
|
||||
//
|
||||
|
||||
struct BuildId {
|
||||
i64 size() const;
|
||||
i64 size() const {
|
||||
switch (kind) {
|
||||
case HEX:
|
||||
return value.size();
|
||||
case HASH:
|
||||
return hash_size;
|
||||
case UUID:
|
||||
return 16;
|
||||
default:
|
||||
unreachable();
|
||||
}
|
||||
}
|
||||
|
||||
enum { NONE, HEX, HASH, UUID } kind = NONE;
|
||||
std::vector<u8> value;
|
||||
@ -2411,8 +2427,8 @@ template <typename E>
|
||||
std::string_view MergeableSection<E>::get_contents(i64 i) {
|
||||
i64 cur = frag_offsets[i];
|
||||
if (i == frag_offsets.size() - 1)
|
||||
return contents.substr(cur);
|
||||
return contents.substr(cur, frag_offsets[i + 1] - cur);
|
||||
return section->contents.substr(cur);
|
||||
return section->contents.substr(cur, frag_offsets[i + 1] - cur);
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
|
@ -1,7 +1,5 @@
|
||||
#include "mold.h"
|
||||
|
||||
#include "config.h"
|
||||
#include "blake3.h"
|
||||
|
||||
#include <cctype>
|
||||
#include <set>
|
||||
@ -1915,15 +1913,26 @@ MergedSection<E>::MergedSection(std::string_view name, i64 flags, i64 type,
|
||||
template <typename E>
|
||||
MergedSection<E> *
|
||||
MergedSection<E>::get_instance(Context<E> &ctx, std::string_view name,
|
||||
i64 type, i64 flags,
|
||||
i64 entsize, i64 addralign) {
|
||||
const ElfShdr<E> &shdr) {
|
||||
if (!(shdr.sh_flags & SHF_MERGE))
|
||||
return nullptr;
|
||||
|
||||
i64 addralign = std::max<i64>(1, shdr.sh_addralign);
|
||||
i64 flags = shdr.sh_flags & ~(u64)SHF_GROUP & ~(u64)SHF_COMPRESSED;
|
||||
|
||||
i64 entsize = shdr.sh_entsize;
|
||||
if (entsize == 0)
|
||||
entsize = (shdr.sh_flags & SHF_STRINGS) ? 1 : (i64)shdr.sh_addralign;
|
||||
if (entsize == 0)
|
||||
return nullptr;
|
||||
|
||||
name = get_merged_output_name(ctx, name, flags, entsize, addralign);
|
||||
flags = flags & ~(u64)SHF_GROUP & ~(u64)SHF_COMPRESSED;
|
||||
|
||||
auto find = [&]() -> MergedSection * {
|
||||
for (std::unique_ptr<MergedSection<E>> &osec : ctx.merged_sections)
|
||||
if (name == osec->name && flags == osec->shdr.sh_flags &&
|
||||
type == osec->shdr.sh_type && entsize == osec->shdr.sh_entsize)
|
||||
shdr.sh_type == osec->shdr.sh_type &&
|
||||
entsize == osec->shdr.sh_entsize)
|
||||
return osec.get();
|
||||
return nullptr;
|
||||
};
|
||||
@ -1941,7 +1950,7 @@ MergedSection<E>::get_instance(Context<E> &ctx, std::string_view name,
|
||||
if (MergedSection *osec = find())
|
||||
return osec;
|
||||
|
||||
MergedSection *osec = new MergedSection(name, flags, type, entsize);
|
||||
MergedSection *osec = new MergedSection(name, flags, shdr.sh_type, entsize);
|
||||
ctx.merged_sections.emplace_back(osec);
|
||||
return osec;
|
||||
}
|
||||
@ -2526,89 +2535,21 @@ void VerdefSection<E>::copy_buf(Context<E> &ctx) {
|
||||
write_vector(ctx.buf + this->shdr.sh_offset, contents);
|
||||
}
|
||||
|
||||
inline i64 BuildId::size() const {
|
||||
switch (kind) {
|
||||
case HEX:
|
||||
return value.size();
|
||||
case HASH:
|
||||
return hash_size;
|
||||
case UUID:
|
||||
return 16;
|
||||
default:
|
||||
unreachable();
|
||||
}
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
void BuildIdSection<E>::update_shdr(Context<E> &ctx) {
|
||||
this->shdr.sh_size = HEADER_SIZE + ctx.arg.build_id.size();
|
||||
this->shdr.sh_size = ctx.arg.build_id.size() + 16; // +16 for the header
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
void BuildIdSection<E>::copy_buf(Context<E> &ctx) {
|
||||
U32<E> *base = (U32<E> *)(ctx.buf + this->shdr.sh_offset);
|
||||
memset(base, 0, this->shdr.sh_size);
|
||||
base[0] = 4; // Name size
|
||||
base[1] = ctx.arg.build_id.size(); // Hash size
|
||||
base[2] = NT_GNU_BUILD_ID; // Type
|
||||
memcpy(base + 3, "GNU", 4); // Name string
|
||||
}
|
||||
|
||||
// BLAKE3 is a cryptographic hash function just like SHA256.
|
||||
// We use it instead of SHA256 because it's faster.
|
||||
static void blake3_hash(u8 *buf, i64 size, u8 *out) {
|
||||
blake3_hasher hasher;
|
||||
blake3_hasher_init(&hasher);
|
||||
blake3_hasher_update(&hasher, buf, size);
|
||||
blake3_hasher_finalize(&hasher, out, BLAKE3_OUT_LEN);
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
void BuildIdSection<E>::write_buildid(Context<E> &ctx) {
|
||||
Timer t(ctx, "build_id");
|
||||
u8 *buf = ctx.buf + this->shdr.sh_offset + HEADER_SIZE;
|
||||
|
||||
switch (ctx.arg.build_id.kind) {
|
||||
case BuildId::HEX:
|
||||
write_vector(buf, ctx.arg.build_id.value);
|
||||
return;
|
||||
case BuildId::HASH: {
|
||||
i64 shard_size = 4 * 1024 * 1024;
|
||||
i64 filesize = ctx.output_file->filesize;
|
||||
i64 num_shards = align_to(filesize, shard_size) / shard_size;
|
||||
std::vector<u8> shards(num_shards * BLAKE3_OUT_LEN);
|
||||
|
||||
tbb::parallel_for((i64)0, num_shards, [&](i64 i) {
|
||||
u8 *begin = ctx.buf + shard_size * i;
|
||||
u8 *end = (i == num_shards - 1) ? ctx.buf + filesize : begin + shard_size;
|
||||
blake3_hash(begin, end - begin, shards.data() + i * BLAKE3_OUT_LEN);
|
||||
|
||||
#ifdef HAVE_MADVISE
|
||||
// Make the kernel page out the file contents we've just written
|
||||
// so that subsequent close(2) call will become quicker.
|
||||
if (i > 0 && ctx.output_file->is_mmapped)
|
||||
madvise(begin, end - begin, MADV_DONTNEED);
|
||||
#endif
|
||||
});
|
||||
|
||||
u8 digest[BLAKE3_OUT_LEN];
|
||||
blake3_hash(shards.data(), shards.size(), digest);
|
||||
|
||||
assert(ctx.arg.build_id.size() <= BLAKE3_OUT_LEN);
|
||||
memcpy(buf, digest, ctx.arg.build_id.size());
|
||||
return;
|
||||
}
|
||||
case BuildId::UUID: {
|
||||
get_random_bytes(buf, 16);
|
||||
|
||||
// Indicate that this is UUIDv4 as defined by RFC4122
|
||||
buf[6] = (buf[6] & 0b0000'1111) | 0b0100'0000;
|
||||
buf[8] = (buf[8] & 0b0011'1111) | 0b1000'0000;
|
||||
return;
|
||||
}
|
||||
default:
|
||||
unreachable();
|
||||
}
|
||||
base[0] = 4; // Name size
|
||||
base[1] = ctx.arg.build_id.size(); // Hash size
|
||||
base[2] = NT_GNU_BUILD_ID; // Type
|
||||
memcpy(base + 3, "GNU", 4); // Name string
|
||||
write_vector(base + 4, contents); // Build ID
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
|
107
elf/passes.cc
107
elf/passes.cc
@ -1,4 +1,5 @@
|
||||
#include "mold.h"
|
||||
#include "blake3.h"
|
||||
|
||||
#include <fstream>
|
||||
#include <functional>
|
||||
@ -442,10 +443,13 @@ static std::string get_cmdline_args(Context<E> &ctx) {
|
||||
|
||||
template <typename E>
|
||||
void add_comment_string(Context<E> &ctx, std::string str) {
|
||||
MergedSection<E> *sec =
|
||||
MergedSection<E>::get_instance(ctx, ".comment", SHT_PROGBITS,
|
||||
SHF_MERGE | SHF_STRINGS, 1, 1);
|
||||
ElfShdr<E> shdr = {};
|
||||
shdr.sh_type = SHT_PROGBITS;
|
||||
shdr.sh_flags = SHF_MERGE | SHF_STRINGS;
|
||||
shdr.sh_entsize = 1;
|
||||
shdr.sh_addralign = 1;
|
||||
|
||||
MergedSection<E> *sec = MergedSection<E>::get_instance(ctx, ".comment", shdr);
|
||||
if (sec->map.nbuckets == 0)
|
||||
sec->map.resize(4096);
|
||||
|
||||
@ -1720,6 +1724,22 @@ void copy_chunks(Context<E> &ctx) {
|
||||
|
||||
if constexpr (is_arm32<E>)
|
||||
fixup_arm_exidx_section(ctx);
|
||||
|
||||
// Zero-clear paddings between chunks
|
||||
auto zero = [&](Chunk<E> *chunk, i64 next_start) {
|
||||
i64 pos = chunk->shdr.sh_offset + chunk->shdr.sh_size;
|
||||
memset(ctx.buf + pos, 0, next_start - pos);
|
||||
};
|
||||
|
||||
std::vector<Chunk<E> *> chunks = ctx.chunks;
|
||||
|
||||
std::erase_if(chunks, [](Chunk<E> *chunk) {
|
||||
return chunk->shdr.sh_type == SHT_NOBITS;
|
||||
});
|
||||
|
||||
for (i64 i = 1; i < chunks.size(); i++)
|
||||
zero(chunks[i - 1], chunks[i]->shdr.sh_offset);
|
||||
zero(chunks.back(), ctx.output_file->filesize);
|
||||
}
|
||||
|
||||
// Rewrite the leading endbr64 instruction with a nop if a function
|
||||
@ -2168,26 +2188,6 @@ void compute_address_significance(Context<E> &ctx) {
|
||||
});
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
void clear_padding(Context<E> &ctx) {
|
||||
Timer t(ctx, "clear_padding");
|
||||
|
||||
auto zero = [&](Chunk<E> *chunk, i64 next_start) {
|
||||
i64 pos = chunk->shdr.sh_offset + chunk->shdr.sh_size;
|
||||
memset(ctx.buf + pos, 0, next_start - pos);
|
||||
};
|
||||
|
||||
std::vector<Chunk<E> *> chunks = ctx.chunks;
|
||||
|
||||
std::erase_if(chunks, [](Chunk<E> *chunk) {
|
||||
return chunk->shdr.sh_type == SHT_NOBITS;
|
||||
});
|
||||
|
||||
for (i64 i = 1; i < chunks.size(); i++)
|
||||
zero(chunks[i - 1], chunks[i]->shdr.sh_offset);
|
||||
zero(chunks.back(), ctx.output_file->filesize);
|
||||
}
|
||||
|
||||
// We want to sort output chunks in the following order.
|
||||
//
|
||||
// <ELF header>
|
||||
@ -2999,6 +2999,65 @@ i64 compress_debug_sections(Context<E> &ctx) {
|
||||
return set_osec_offsets(ctx);
|
||||
}
|
||||
|
||||
// BLAKE3 is a cryptographic hash function just like SHA256.
|
||||
// We use it instead of SHA256 because it's faster.
|
||||
static void blake3_hash(u8 *buf, i64 size, u8 *out) {
|
||||
blake3_hasher hasher;
|
||||
blake3_hasher_init(&hasher);
|
||||
blake3_hasher_update(&hasher, buf, size);
|
||||
blake3_hasher_finalize(&hasher, out, BLAKE3_OUT_LEN);
|
||||
}
|
||||
|
||||
template <typename E>
|
||||
void compute_build_id(Context<E> &ctx) {
|
||||
Timer t(ctx, "compute_build_id");
|
||||
|
||||
switch (ctx.arg.build_id.kind) {
|
||||
case BuildId::HEX:
|
||||
ctx.buildid->contents = ctx.arg.build_id.value;
|
||||
break;
|
||||
case BuildId::HASH: {
|
||||
i64 shard_size = 4 * 1024 * 1024;
|
||||
i64 filesize = ctx.output_file->filesize;
|
||||
i64 num_shards = align_to(filesize, shard_size) / shard_size;
|
||||
std::vector<u8> shards(num_shards * BLAKE3_OUT_LEN);
|
||||
|
||||
tbb::parallel_for((i64)0, num_shards, [&](i64 i) {
|
||||
u8 *begin = ctx.buf + shard_size * i;
|
||||
u8 *end = (i == num_shards - 1) ? ctx.buf + filesize : begin + shard_size;
|
||||
blake3_hash(begin, end - begin, shards.data() + i * BLAKE3_OUT_LEN);
|
||||
|
||||
#ifdef HAVE_MADVISE
|
||||
// Make the kernel page out the file contents we've just written
|
||||
// so that subsequent close(2) call will become quicker.
|
||||
if (i > 0 && ctx.output_file->is_mmapped)
|
||||
madvise(begin, end - begin, MADV_DONTNEED);
|
||||
#endif
|
||||
});
|
||||
|
||||
u8 buf[BLAKE3_OUT_LEN];
|
||||
blake3_hash(shards.data(), shards.size(), buf);
|
||||
|
||||
assert(ctx.arg.build_id.size() <= BLAKE3_OUT_LEN);
|
||||
ctx.buildid->contents = {buf, buf + ctx.arg.build_id.size()};
|
||||
break;
|
||||
}
|
||||
case BuildId::UUID: {
|
||||
u8 buf[16];
|
||||
get_random_bytes(buf, 16);
|
||||
|
||||
// Indicate that this is UUIDv4 as defined by RFC4122
|
||||
buf[6] = (buf[6] & 0b0000'1111) | 0b0100'0000;
|
||||
buf[8] = (buf[8] & 0b0011'1111) | 0b1000'0000;
|
||||
ctx.buildid->contents = {buf, buf + 16};
|
||||
break;
|
||||
}
|
||||
default:
|
||||
unreachable();
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
// Write Makefile-style dependency rules to a file specified by
|
||||
// --dependency-file. This is analogous to the compiler's -M flag.
|
||||
template <typename E>
|
||||
@ -3134,11 +3193,11 @@ template void apply_version_script(Context<E> &);
|
||||
template void parse_symbol_version(Context<E> &);
|
||||
template void compute_import_export(Context<E> &);
|
||||
template void compute_address_significance(Context<E> &);
|
||||
template void clear_padding(Context<E> &);
|
||||
template void compute_section_headers(Context<E> &);
|
||||
template i64 set_osec_offsets(Context<E> &);
|
||||
template void fix_synthetic_symbols(Context<E> &);
|
||||
template i64 compress_debug_sections(Context<E> &);
|
||||
template void compute_build_id(Context<E> &);
|
||||
template void write_dependency_file(Context<E> &);
|
||||
template void show_stats(Context<E> &);
|
||||
|
||||
|
@ -176,7 +176,6 @@ void combine_objects(Context<E> &ctx) {
|
||||
ctx.buf = ctx.output_file->buf;
|
||||
|
||||
copy_chunks(ctx);
|
||||
clear_padding(ctx);
|
||||
ctx.output_file->close(ctx);
|
||||
ctx.checkpoint();
|
||||
|
||||
|
@ -1,5 +1,3 @@
|
||||
#if !defined(_WIN32) && !defined(__APPLE__)
|
||||
|
||||
#include "mold.h"
|
||||
#include "config.h"
|
||||
|
||||
@ -14,10 +12,12 @@
|
||||
namespace mold::elf {
|
||||
|
||||
#ifdef MOLD_X86_64
|
||||
static int pipe_write_fd = -1;
|
||||
|
||||
// Exiting from a program with large memory usage is slow --
|
||||
// it may take a few hundred milliseconds. To hide the latency,
|
||||
// we fork a child and let it do the actual linking work.
|
||||
std::function<void()> fork_child() {
|
||||
void fork_child() {
|
||||
int pipefd[2];
|
||||
if (pipe(pipefd) == -1) {
|
||||
perror("pipe");
|
||||
@ -50,12 +50,16 @@ std::function<void()> fork_child() {
|
||||
|
||||
// Child
|
||||
close(pipefd[0]);
|
||||
pipe_write_fd = pipefd[1];
|
||||
}
|
||||
|
||||
return [=] {
|
||||
char buf[] = {1};
|
||||
[[maybe_unused]] int n = write(pipefd[1], buf, 1);
|
||||
assert(n == 1);
|
||||
};
|
||||
void notify_parent() {
|
||||
if (pipe_write_fd == -1)
|
||||
return;
|
||||
|
||||
char buf[] = {1};
|
||||
[[maybe_unused]] int n = write(pipe_write_fd, buf, 1);
|
||||
assert(n == 1);
|
||||
}
|
||||
#endif
|
||||
|
||||
@ -84,6 +88,9 @@ static std::string find_dso(Context<E> &ctx, std::filesystem::path self) {
|
||||
template <typename E>
|
||||
[[noreturn]]
|
||||
void process_run_subcommand(Context<E> &ctx, int argc, char **argv) {
|
||||
#ifdef __APPLE__
|
||||
Fatal(ctx) << "-run is not supported on macOS";
|
||||
#else
|
||||
assert(argv[1] == "-run"s || argv[1] == "--run"s);
|
||||
|
||||
if (!argv[2])
|
||||
@ -111,6 +118,7 @@ void process_run_subcommand(Context<E> &ctx, int argc, char **argv) {
|
||||
// Execute a given command
|
||||
execvp(argv[2], argv + 2);
|
||||
Fatal(ctx) << "mold -run failed: " << argv[2] << ": " << errno_string();
|
||||
#endif
|
||||
}
|
||||
|
||||
using E = MOLD_TARGET;
|
||||
@ -118,5 +126,3 @@ using E = MOLD_TARGET;
|
||||
template void process_run_subcommand(Context<E> &, int, char **);
|
||||
|
||||
} // namespace mold::elf
|
||||
|
||||
#endif
|
20
elf/subprocess-win32.cc
Normal file
20
elf/subprocess-win32.cc
Normal file
@ -0,0 +1,20 @@
|
||||
#include "mold.h"
|
||||
|
||||
namespace mold::elf {
|
||||
|
||||
#ifdef MOLD_X86_64
|
||||
void fork_child() {}
|
||||
void notify_parent() {}
|
||||
#endif
|
||||
|
||||
template <typename E>
|
||||
[[noreturn]]
|
||||
void process_run_subcommand(Context<E> &ctx, int argc, char **argv) {
|
||||
Fatal(ctx) << "-run is supported only on Unix";
|
||||
}
|
||||
|
||||
using E = MOLD_TARGET;
|
||||
|
||||
template void process_run_subcommand(Context<E> &, int, char **);
|
||||
|
||||
} // namespace mold::elf
|
Loading…
Reference in New Issue
Block a user