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Fix global cache destruction in IdString class
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When enabling LTO on GCC, the sequence of destructing static members in
IdString class is not promised, which can lead to the cache itself being
destructed but the destruct_guard not destructed.

Put all static members of IdString to a subclass similar to current
desturct_guard_t, to mmakes the guard a real guard.

This fixes SEGV when exiting a LTO-ed GCC-built yosys binary.

Signed-off-by: Icenowy Zheng <[email protected]>
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@Icenowy
Icenowy committed Aug 28, 2023
1 parent 2f901a8 commit 001a63f
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Showing 2 changed files with 159 additions and 166 deletions.
13 changes: 1 addition & 12 deletions kernel/rtlil.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -30,18 +30,7 @@

YOSYS_NAMESPACE_BEGIN

bool RTLIL::IdString::destruct_guard_ok = false;
RTLIL::IdString::destruct_guard_t RTLIL::IdString::destruct_guard;
std::vector<char*> RTLIL::IdString::global_id_storage_;
dict<char*, int, hash_cstr_ops> RTLIL::IdString::global_id_index_;
#ifndef YOSYS_NO_IDS_REFCNT
std::vector<int> RTLIL::IdString::global_refcount_storage_;
std::vector<int> RTLIL::IdString::global_free_idx_list_;
#endif
#ifdef YOSYS_USE_STICKY_IDS
int RTLIL::IdString::last_created_idx_[8];
int RTLIL::IdString::last_created_idx_ptr_;
#endif
RTLIL::IdString::global_cache_t RTLIL::IdString::global_cache;

#define X(_id) IdString RTLIL::ID::_id;
#include "kernel/constids.inc"
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312 changes: 158 additions & 154 deletions kernel/rtlil.h
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Original file line number Diff line number Diff line change
Expand Up @@ -85,193 +85,197 @@ namespace RTLIL

// the global id string cache

static bool destruct_guard_ok; // POD, will be initialized to zero
static struct destruct_guard_t {
destruct_guard_t() { destruct_guard_ok = true; }
~destruct_guard_t() { destruct_guard_ok = false; }
} destruct_guard;

static std::vector<char*> global_id_storage_;
static dict<char*, int, hash_cstr_ops> global_id_index_;
#ifndef YOSYS_NO_IDS_REFCNT
static std::vector<int> global_refcount_storage_;
static std::vector<int> global_free_idx_list_;
#endif

#ifdef YOSYS_USE_STICKY_IDS
static int last_created_idx_ptr_;
static int last_created_idx_[8];
#endif

static inline void xtrace_db_dump()
{
#ifdef YOSYS_XTRACE_GET_PUT
for (int idx = 0; idx < GetSize(global_id_storage_); idx++)
{
if (global_id_storage_.at(idx) == nullptr)
log("#X# DB-DUMP index %d: FREE\n", idx);
else
log("#X# DB-DUMP index %d: '%s' (ref %d)\n", idx, global_id_storage_.at(idx), global_refcount_storage_.at(idx));
}
static struct global_cache_t {
bool destruct_guard; // POD, will be initialized to zero
global_cache_t() { destruct_guard = true; }
~global_cache_t() { destruct_guard = false; }

std::vector<char*> global_id_storage_;
dict<char*, int, hash_cstr_ops> global_id_index_;
#ifndef YOSYS_NO_IDS_REFCNT
std::vector<int> global_refcount_storage_;
std::vector<int> global_free_idx_list_;
#endif
}

static inline void checkpoint()
{
#ifdef YOSYS_USE_STICKY_IDS
last_created_idx_ptr_ = 0;
for (int i = 0; i < 8; i++) {
if (last_created_idx_[i])
put_reference(last_created_idx_[i]);
last_created_idx_[i] = 0;
}
#endif
#ifdef YOSYS_SORT_ID_FREE_LIST
std::sort(global_free_idx_list_.begin(), global_free_idx_list_.end(), std::greater<int>());
int last_created_idx_ptr_;
int last_created_idx_[8];
#endif
}

static inline int get_reference(int idx)
{
if (idx) {
#ifndef YOSYS_NO_IDS_REFCNT
global_refcount_storage_[idx]++;
#endif
#ifdef YOSYS_XTRACE_GET_PUT
if (yosys_xtrace)
log("#X# GET-BY-INDEX '%s' (index %d, refcount %d)\n", global_id_storage_.at(idx), idx, global_refcount_storage_.at(idx));
#endif
inline void xtrace_db_dump()
{
#ifdef YOSYS_XTRACE_GET_PUT
for (int idx = 0; idx < GetSize(global_id_storage_); idx++)
{
if (global_id_storage_.at(idx) == nullptr)
log("#X# DB-DUMP index %d: FREE\n", idx);
else
log("#X# DB-DUMP index %d: '%s' (ref %d)\n", idx, global_id_storage_.at(idx), global_refcount_storage_.at(idx));
}
#endif
}
return idx;
}

static int get_reference(const char *p)
{
log_assert(destruct_guard_ok);

if (!p[0])
return 0;
inline void checkpoint()
{
#ifdef YOSYS_USE_STICKY_IDS
last_created_idx_ptr_ = 0;
for (int i = 0; i < 8; i++) {
if (last_created_idx_[i])
put_reference(last_created_idx_[i]);
last_created_idx_[i] = 0;
}
#endif
#ifdef YOSYS_SORT_ID_FREE_LIST
std::sort(global_free_idx_list_.begin(), global_free_idx_list_.end(), std::greater<int>());
#endif
}

auto it = global_id_index_.find((char*)p);
if (it != global_id_index_.end()) {
#ifndef YOSYS_NO_IDS_REFCNT
global_refcount_storage_.at(it->second)++;
#endif
#ifdef YOSYS_XTRACE_GET_PUT
if (yosys_xtrace)
log("#X# GET-BY-NAME '%s' (index %d, refcount %d)\n", global_id_storage_.at(it->second), it->second, global_refcount_storage_.at(it->second));
#endif
return it->second;
inline int get_reference(int idx)
{
if (idx) {
#ifndef YOSYS_NO_IDS_REFCNT
global_refcount_storage_[idx]++;
#endif
#ifdef YOSYS_XTRACE_GET_PUT
if (yosys_xtrace)
log("#X# GET-BY-INDEX '%s' (index %d, refcount %d)\n", global_id_storage_.at(idx), idx, global_refcount_storage_.at(idx));
#endif
}
return idx;
}

log_assert(p[0] == '$' || p[0] == '\\');
log_assert(p[1] != 0);
for (const char *c = p; *c; c++)
if ((unsigned)*c <= (unsigned)' ')
log_error("Found control character or space (0x%02x) in string '%s' which is not allowed in RTLIL identifiers\n", *c, p);
int get_reference(const char *p)
{
log_assert(destruct_guard);

if (!p[0])
return 0;

auto it = global_id_index_.find((char*)p);
if (it != global_id_index_.end()) {
#ifndef YOSYS_NO_IDS_REFCNT
global_refcount_storage_.at(it->second)++;
#endif
#ifdef YOSYS_XTRACE_GET_PUT
if (yosys_xtrace)
log("#X# GET-BY-NAME '%s' (index %d, refcount %d)\n", global_id_storage_.at(it->second), it->second, global_refcount_storage_.at(it->second));
#endif
return it->second;
}

log_assert(p[0] == '$' || p[0] == '\\');
log_assert(p[1] != 0);
for (const char *c = p; *c; c++)
if ((unsigned)*c <= (unsigned)' ')
log_error("Found control character or space (0x%02x) in string '%s' which is not allowed in RTLIL identifiers\n", *c, p);

#ifndef YOSYS_NO_IDS_REFCNT
if (global_free_idx_list_.empty()) {
if (global_id_storage_.empty()) {
global_refcount_storage_.push_back(0);
global_id_storage_.push_back((char*)"");
global_id_index_[global_id_storage_.back()] = 0;
}
log_assert(global_id_storage_.size() < 0x40000000);
global_free_idx_list_.push_back(global_id_storage_.size());
global_id_storage_.push_back(nullptr);
global_refcount_storage_.push_back(0);
}

#ifndef YOSYS_NO_IDS_REFCNT
if (global_free_idx_list_.empty()) {
int idx = global_free_idx_list_.back();
global_free_idx_list_.pop_back();
global_id_storage_.at(idx) = strdup(p);
global_id_index_[global_id_storage_.at(idx)] = idx;
global_refcount_storage_.at(idx)++;
#else
if (global_id_storage_.empty()) {
global_refcount_storage_.push_back(0);
global_id_storage_.push_back((char*)"");
global_id_index_[global_id_storage_.back()] = 0;
}
log_assert(global_id_storage_.size() < 0x40000000);
global_free_idx_list_.push_back(global_id_storage_.size());
global_id_storage_.push_back(nullptr);
global_refcount_storage_.push_back(0);
}
int idx = global_id_storage_.size();
global_id_storage_.push_back(strdup(p));
global_id_index_[global_id_storage_.back()] = idx;
#endif

if (yosys_xtrace) {
log("#X# New IdString '%s' with index %d.\n", p, idx);
log_backtrace("-X- ", yosys_xtrace-1);
}

int idx = global_free_idx_list_.back();
global_free_idx_list_.pop_back();
global_id_storage_.at(idx) = strdup(p);
global_id_index_[global_id_storage_.at(idx)] = idx;
global_refcount_storage_.at(idx)++;
#else
if (global_id_storage_.empty()) {
global_id_storage_.push_back((char*)"");
global_id_index_[global_id_storage_.back()] = 0;
#ifdef YOSYS_XTRACE_GET_PUT
if (yosys_xtrace)
log("#X# GET-BY-NAME '%s' (index %d, refcount %d)\n", global_id_storage_.at(idx), idx, global_refcount_storage_.at(idx));
#endif

#ifdef YOSYS_USE_STICKY_IDS
// Avoid Create->Delete->Create pattern
if (last_created_idx_[last_created_idx_ptr_])
put_reference(last_created_idx_[last_created_idx_ptr_]);
last_created_idx_[last_created_idx_ptr_] = idx;
get_reference(last_created_idx_[last_created_idx_ptr_]);
last_created_idx_ptr_ = (last_created_idx_ptr_ + 1) & 7;
#endif

return idx;
}
int idx = global_id_storage_.size();
global_id_storage_.push_back(strdup(p));
global_id_index_[global_id_storage_.back()] = idx;
#endif

if (yosys_xtrace) {
log("#X# New IdString '%s' with index %d.\n", p, idx);
log_backtrace("-X- ", yosys_xtrace-1);
}
#ifndef YOSYS_NO_IDS_REFCNT
inline void put_reference(int idx)
{
// put_reference() may be called from destructors after the destructor of
// global_refcount_storage_ has been run. in this case we simply do nothing.
if (!destruct_guard || !idx)
return;

#ifdef YOSYS_XTRACE_GET_PUT
if (yosys_xtrace) {
log("#X# PUT '%s' (index %d, refcount %d)\n", global_id_storage_.at(idx), idx, global_refcount_storage_.at(idx));
}
#endif

#ifdef YOSYS_XTRACE_GET_PUT
if (yosys_xtrace)
log("#X# GET-BY-NAME '%s' (index %d, refcount %d)\n", global_id_storage_.at(idx), idx, global_refcount_storage_.at(idx));
#endif
int &refcount = global_refcount_storage_[idx];

#ifdef YOSYS_USE_STICKY_IDS
// Avoid Create->Delete->Create pattern
if (last_created_idx_[last_created_idx_ptr_])
put_reference(last_created_idx_[last_created_idx_ptr_]);
last_created_idx_[last_created_idx_ptr_] = idx;
get_reference(last_created_idx_[last_created_idx_ptr_]);
last_created_idx_ptr_ = (last_created_idx_ptr_ + 1) & 7;
#endif
if (--refcount > 0)
return;

return idx;
}
log_assert(refcount == 0);
free_reference(idx);
}
inline void free_reference(int idx)
{
if (yosys_xtrace) {
log("#X# Removed IdString '%s' with index %d.\n", global_id_storage_.at(idx), idx);
log_backtrace("-X- ", yosys_xtrace-1);
}

#ifndef YOSYS_NO_IDS_REFCNT
static inline void put_reference(int idx)
{
// put_reference() may be called from destructors after the destructor of
// global_refcount_storage_ has been run. in this case we simply do nothing.
if (!destruct_guard_ok || !idx)
return;

#ifdef YOSYS_XTRACE_GET_PUT
if (yosys_xtrace) {
log("#X# PUT '%s' (index %d, refcount %d)\n", global_id_storage_.at(idx), idx, global_refcount_storage_.at(idx));
global_id_index_.erase(global_id_storage_.at(idx));
free(global_id_storage_.at(idx));
global_id_storage_.at(idx) = nullptr;
global_free_idx_list_.push_back(idx);
}
#else
inline void put_reference(int) { }
#endif

int &refcount = global_refcount_storage_[idx];

if (--refcount > 0)
return;

log_assert(refcount == 0);
free_reference(idx);
}
static inline void free_reference(int idx)
{
if (yosys_xtrace) {
log("#X# Removed IdString '%s' with index %d.\n", global_id_storage_.at(idx), idx);
log_backtrace("-X- ", yosys_xtrace-1);
}
} global_cache;

global_id_index_.erase(global_id_storage_.at(idx));
free(global_id_storage_.at(idx));
global_id_storage_.at(idx) = nullptr;
global_free_idx_list_.push_back(idx);
}
#else
static inline void put_reference(int) { }
#endif
static inline void xtrace_db_dump() { global_cache.xtrace_db_dump(); }
static inline void checkpoint() { global_cache.checkpoint(); }

// the actual IdString object is just is a single int

int index_;

inline IdString() : index_(0) { }
inline IdString(const char *str) : index_(get_reference(str)) { }
inline IdString(const IdString &str) : index_(get_reference(str.index_)) { }
inline IdString(const char *str) : index_(global_cache.get_reference(str)) { }
inline IdString(const IdString &str) : index_(global_cache.get_reference(str.index_)) { }
inline IdString(IdString &&str) : index_(str.index_) { str.index_ = 0; }
inline IdString(const std::string &str) : index_(get_reference(str.c_str())) { }
inline ~IdString() { put_reference(index_); }
inline IdString(const std::string &str) : index_(global_cache.get_reference(str.c_str())) { }
inline ~IdString() { global_cache.put_reference(index_); }

inline void operator=(const IdString &rhs) {
put_reference(index_);
index_ = get_reference(rhs.index_);
global_cache.put_reference(index_);
index_ = global_cache.get_reference(rhs.index_);
}

inline void operator=(const char *rhs) {
Expand All @@ -285,11 +289,11 @@ namespace RTLIL
}

inline const char *c_str() const {
return global_id_storage_.at(index_);
return global_cache.global_id_storage_.at(index_);
}

inline std::string str() const {
return std::string(global_id_storage_.at(index_));
return std::string(global_cache.global_id_storage_.at(index_));
}

inline bool operator<(const IdString &rhs) const {
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