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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "index_lookup_table.h"
#include <vespa/eval/eval/value_type.h>
#include <vespa/eval/eval/key_gen.h>
#include <vespa/eval/eval/llvm/compiled_function.h>
namespace vespalib::eval {
namespace {
bool step_params(std::vector<double> ¶ms, const ValueType &type) {
const auto &dims = type.dimensions();
for (size_t idx = params.size(); idx-- > 0; ) {
if (size_t(params[idx] += 1.0) < dims[idx].size) {
return true;
} else {
params[idx] = 0.0;
}
}
return false;
}
std::vector<uint32_t> make_index_table(const Function &idx_fun, const ValueType &type) {
std::vector<uint32_t> result;
result.reserve(type.dense_subspace_size());
std::vector<double> params(type.dimensions().size(), 0.0);
CompiledFunction cfun(idx_fun, PassParams::ARRAY);
auto fun = cfun.get_function();
do {
result.push_back(uint32_t(fun(¶ms[0])));
} while(step_params(params, type));
assert(result.size() == type.dense_subspace_size());
return result;
}
}
std::mutex IndexLookupTable::_lock{};
IndexLookupTable::Map IndexLookupTable::_cached{};
size_t
IndexLookupTable::num_cached()
{
std::lock_guard<std::mutex> guard(_lock);
return _cached.size();
}
size_t
IndexLookupTable::count_refs()
{
std::lock_guard<std::mutex> guard(_lock);
size_t refs = 0;
for (const auto &entry: _cached) {
refs += entry.second.num_refs;
}
return refs;
}
IndexLookupTable::Token::UP
IndexLookupTable::create(const Function &idx_fun, const ValueType &type)
{
assert(type.is_dense());
assert(idx_fun.num_params() == type.dimensions().size());
assert(!CompiledFunction::detect_issues(idx_fun));
auto key = type.to_spec() + gen_key(idx_fun, PassParams::ARRAY);
{
std::lock_guard<std::mutex> guard(_lock);
auto pos = _cached.find(key);
if (pos != _cached.end()) {
++(pos->second.num_refs);
return std::make_unique<Token>(pos, Token::ctor_tag());
}
}
// avoid holding the lock while making the index table
auto table = make_index_table(idx_fun, type);
{
std::lock_guard<std::mutex> guard(_lock);
auto pos = _cached.find(key);
if (pos != _cached.end()) {
++(pos->second.num_refs);
// in case of a race; return the same table for all callers
return std::make_unique<Token>(pos, Token::ctor_tag());
} else {
auto res = _cached.emplace(std::move(key), Value::ctor_tag());
assert(res.second);
res.first->second.data = std::move(table);
return std::make_unique<Token>(res.first, Token::ctor_tag());
}
}
}
}
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