void* LibraryList::FindSymbolFrom(const char* symbol_name, LibraryView* from) {
SymbolLookupState lookup_state;
if (!from)
return NULL;
// Use a work-queue and a set to ensure to perform a breadth-first
// search.
Vector<LibraryView*> work_queue;
Set<LibraryView*> visited_set;
work_queue.PushBack(from);
while (!work_queue.IsEmpty()) {
LibraryView* lib = work_queue.PopFirst();
if (lib->IsCrazy()) {
if (lookup_state.CheckSymbol(symbol_name, lib->GetCrazy()))
return lookup_state.found_addr;
} else if (lib->IsSystem()) {
// TODO(digit): Support weak symbols in system libraries.
// With the current code, all symbols in system libraries
// are assumed to be non-weak.
void* addr = lib->LookupSymbol(symbol_name);
if (addr)
return addr;
}
// If this is a crazy library, add non-visited dependencies
// to the work queue.
if (lib->IsCrazy()) {
SharedLibrary::DependencyIterator iter(lib->GetCrazy());
while (iter.GetNext()) {
LibraryView* dependency = FindKnownLibrary(iter.GetName());
if (dependency && !visited_set.Has(dependency)) {
work_queue.PushBack(dependency);
visited_set.Add(dependency);
}
}
}
}
if (lookup_state.weak_count >= 1) {
// There was at least a single weak symbol definition, so use
// the first one found in breadth-first search order.
return lookup_state.weak_addr;
}
// There was no symbol definition.
return NULL;
}
