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debuginfo: Memoize object symbol lookup #58851

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Merged
merged 1 commit into from
Jul 1, 2025
Merged

debuginfo: Memoize object symbol lookup #58851

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7 changes: 5 additions & 2 deletions src/debug-registry.h
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,8 @@ typedef struct {
const llvm::object::ObjectFile *obj;
llvm::DIContext *ctx;
int64_t slide;
} objfileentry_t;
std::map<uintptr_t, StringRef, std::greater<size_t>> *symbolmap;
} jl_object_file_entry_t;

// Central registry for resolving function addresses to `jl_code_instance_t`s and
// originating `ObjectFile`s (for the DWARF debug info).
Expand Down Expand Up @@ -121,7 +122,7 @@ class JITDebugInfoRegistry
using rev_map = std::map<KeyT, ValT, std::greater<KeyT>>;

typedef rev_map<size_t, SectionInfo> objectmap_t;
typedef rev_map<uint64_t, objfileentry_t> objfilemap_t;
typedef rev_map<uint64_t, jl_object_file_entry_t> objfilemap_t;

objectmap_t objectmap{};
rev_map<size_t, std::pair<size_t, jl_code_instance_t *>> cimap{};
Expand Down Expand Up @@ -152,4 +153,6 @@ class JITDebugInfoRegistry
void add_image_info(image_info_t info) JL_NOTSAFEPOINT;
bool get_image_info(uint64_t base, image_info_t *info) const JL_NOTSAFEPOINT;
Locked<objfilemap_t>::LockT get_objfile_map() JL_NOTSAFEPOINT;

std::shared_mutex symbol_mutex;
};
116 changes: 66 additions & 50 deletions src/debuginfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -717,7 +717,8 @@ static inline void ignoreError(T &err) JL_NOTSAFEPOINT
#endif
}

static void get_function_name_and_base(llvm::object::SectionRef Section, size_t pointer, int64_t slide, bool inimage,
static void get_function_name_and_base(llvm::object::SectionRef Section, std::map<uintptr_t, StringRef, std::greater<size_t>> *symbolmap,
size_t pointer, int64_t slide, bool inimage,
void **saddr, char **name, bool untrusted_dladdr) JL_NOTSAFEPOINT
{
bool needs_saddr = saddr && (!*saddr || untrusted_dladdr);
Expand All @@ -743,59 +744,73 @@ static void get_function_name_and_base(llvm::object::SectionRef Section, size_t
#endif
}
if (Section.getObject() && (needs_saddr || needs_name)) {
size_t distance = (size_t)-1;
object::SymbolRef sym_found;
for (auto sym : Section.getObject()->symbols()) {
if (!Section.containsSymbol(sym))
continue;
auto addr = sym.getAddress();
if (!addr)
continue;
size_t symptr = addr.get();
if (symptr > pointer + slide)
continue;
size_t new_dist = pointer + slide - symptr;
if (new_dist > distance)
continue;
distance = new_dist;
sym_found = sym;
}
if (distance != (size_t)-1) {
if (needs_saddr) {
uintptr_t addr = cantFail(sym_found.getAddress());
*saddr = (void*)(addr - slide);
needs_saddr = false;
uintptr_t addr = 0;
StringRef nameref{};
{
std::shared_lock<std::shared_mutex> read_lock(getJITDebugRegistry().symbol_mutex);
if (symbolmap->empty()) {
read_lock.unlock();
{
// symbol map hasn't been generated yet, so fill it in now
std::unique_lock<std::shared_mutex> write_lock(getJITDebugRegistry().symbol_mutex);
if (symbolmap->empty()) {
for (auto sym : Section.getObject()->symbols()) {
if (!Section.containsSymbol(sym))
continue;

auto maybe_addr = sym.getAddress();
if (!maybe_addr)
continue;
size_t addr = maybe_addr.get();

auto maybe_nameref = sym.getName();
StringRef nameref{};
if (maybe_nameref)
nameref = maybe_nameref.get();

symbolmap->emplace(addr, nameref);
}
}
}
read_lock.lock();
}
auto fit = symbolmap->lower_bound(pointer + slide);
if (fit != symbolmap->end()) {
addr = fit->first;
nameref = fit->second;
}
if (needs_name) {
if (auto name_or_err = sym_found.getName()) {
auto nameref = name_or_err.get();
const char globalPrefix = // == DataLayout::getGlobalPrefix
}
std::string namerefstr = nameref.str();
if (needs_saddr && addr != 0) {
*saddr = (void*)(addr - slide);
needs_saddr = false;
}
if (needs_name && !nameref.empty()) {
const char globalPrefix = // == DataLayout::getGlobalPrefix
#if defined(_OS_WINDOWS_) && !defined(_CPU_X86_64_)
'_';
'_';
#elif defined(_OS_DARWIN_)
'_';
'_';
#else
'\0';
'\0';
#endif
if (globalPrefix) {
if (nameref[0] == globalPrefix)
nameref = nameref.drop_front();
if (globalPrefix) {
if (nameref[0] == globalPrefix)
nameref = nameref.drop_front();
#if defined(_OS_WINDOWS_) && !defined(_CPU_X86_64_)
else if (nameref[0] == '@') // X86_VectorCall
nameref = nameref.drop_front();
else if (nameref[0] == '@') // X86_VectorCall
nameref = nameref.drop_front();
#endif
// else VectorCall, Assembly, Internal, etc.
}
// else VectorCall, Assembly, Internal, etc.
}
#if defined(_OS_WINDOWS_) && !defined(_CPU_X86_64_)
nameref = nameref.split('@').first;
nameref = nameref.split('@').first;
#endif
size_t len = nameref.size();
*name = (char*)realloc_s(*name, len + 1);
memcpy(*name, nameref.data(), len);
(*name)[len] = 0;
needs_name = false;
}
}
size_t len = nameref.size();
*name = (char*)realloc_s(*name, len + 1);
memcpy(*name, nameref.data(), len);
(*name)[len] = 0;
needs_name = false;
}
}
#ifdef _OS_WINDOWS_
Expand All @@ -819,7 +834,7 @@ static void get_function_name_and_base(llvm::object::SectionRef Section, size_t
#endif
}

static objfileentry_t find_object_file(uint64_t fbase, StringRef fname) JL_NOTSAFEPOINT
static jl_object_file_entry_t find_object_file(uint64_t fbase, StringRef fname) JL_NOTSAFEPOINT
{
int isdarwin = 0, islinux = 0, iswindows = 0;
#if defined(_OS_DARWIN_)
Expand All @@ -832,7 +847,7 @@ static objfileentry_t find_object_file(uint64_t fbase, StringRef fname) JL_NOTSA
(void)iswindows;

// GOAL: Read debuginfo from file
objfileentry_t entry{nullptr, nullptr, 0};
jl_object_file_entry_t entry{nullptr, nullptr, 0, nullptr};
auto success = getJITDebugRegistry().get_objfile_map()->emplace(fbase, entry);
if (!success.second)
// Return cached value
Expand Down Expand Up @@ -1009,7 +1024,8 @@ static objfileentry_t find_object_file(uint64_t fbase, StringRef fname) JL_NOTSA
auto binary = errorobj->takeBinary();
binary.first.release();
binary.second.release();
entry = {debugobj, context, slide};

entry = {debugobj, context, slide, new std::map<uintptr_t, StringRef, std::greater<size_t>>()};
// update cache
(*getJITDebugRegistry().get_objfile_map())[fbase] = entry;
}
Expand Down Expand Up @@ -1139,15 +1155,15 @@ bool jl_dylib_DI_for_fptr(size_t pointer, object::SectionRef *Section, int64_t *
jl_copy_str(filename, dlinfo.dli_fname);
fname = dlinfo.dli_fname;
#endif // ifdef _OS_WINDOWS_
auto entry = find_object_file(fbase, fname);
jl_object_file_entry_t entry = find_object_file(fbase, fname);
*slide = entry.slide;
*context = entry.ctx;
if (entry.obj)
*Section = getModuleSectionForAddress(entry.obj, pointer + entry.slide);
// Assume we only need base address for sysimg for now
if (!inimage || 0 == image_info.fptrs.nptrs)
saddr = nullptr;
get_function_name_and_base(*Section, pointer, entry.slide, inimage, saddr, name, untrusted_dladdr);
get_function_name_and_base(*Section, entry.symbolmap, pointer, entry.slide, inimage, saddr, name, untrusted_dladdr);
return true;
}

Expand Down