[llvm] [ORC] Add automatic shared library resolver for unresolved symbols. (PR #148410)

[via llvm-commits]

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@@ -0,0 +1,173 @@
+//===--- SymbolFilter.h - Utils for Symbol Filter ---*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_SHARED_SYMBOLFILTER_H
+#define LLVM_EXECUTIONENGINE_ORC_SHARED_SYMBOLFILTER_H
+
+#include "llvm/ExecutionEngine/Orc/Shared/SimplePackedSerialization.h"
+
+#include <math.h>
+#include <type_traits>
+#include <vector>
+
+namespace llvm {
+namespace orc {
+
+namespace shared {
+using SPSBloomFilter =
+    SPSTuple<bool, uint32_t, uint32_t, uint32_t, SPSSequence<uint64_t>>;
+}
+
+class BloomFilter {
+public:
+  using HashFunc = std::function<uint32_t(StringRef)>;
+
+  BloomFilter() = default;
+  BloomFilter(BloomFilter &&) noexcept = default;
+  BloomFilter &operator=(BloomFilter &&) noexcept = default;
+  BloomFilter(const BloomFilter &) = delete;
+  BloomFilter &operator=(const BloomFilter &) = delete;
+
+  BloomFilter(uint32_t symbolCount, float falsePositiveRate, HashFunc hashFn)
+      : hashFunc(std::move(hashFn)) {
+    initialize(symbolCount, falsePositiveRate);
+  }
+  bool IsInitialized() const { return initialized; }
+
+  void add(StringRef symbol) {
+    assert(initialized);
+    addHash(hashFunc(symbol));
+  }
+
+  bool mayContain(StringRef symbol) const {
+    return !isEmpty() && testHash(hashFunc(symbol));
+  }
+
+  bool isEmpty() const { return symbolCount_ == 0; }
+
+private:
+  friend class shared::SPSSerializationTraits<shared::SPSBloomFilter,
+                                              BloomFilter>;
+  static constexpr uint32_t bitsPerEntry = 64;
+
+  bool initialized = false;
+  uint32_t symbolCount_ = 0;
+  uint32_t bloomSize = 0;
+  uint32_t bloomShift = 0;
+  std::vector<uint64_t> bloomTable;
+  HashFunc hashFunc;
+
+  void initialize(uint32_t symbolCount, float falsePositiveRate) {
+    assert(symbolCount > 0);
+    symbolCount_ = symbolCount;
+    initialized = true;
+
+    float ln2 = std::log(2.0f);
+    float m = -1.0f * symbolCount * std::log(falsePositiveRate) / (ln2 * ln2);
+    bloomSize = static_cast<uint32_t>(std::ceil(m / bitsPerEntry));
+    bloomShift = std::min(6u, log2ceil(symbolCount));
+    bloomTable.resize(bloomSize, 0);
+  }
+
+  void addHash(uint32_t hash) {
+    uint32_t hash2 = hash >> bloomShift;
+    uint32_t n = (hash / bitsPerEntry) % bloomSize;
+    uint64_t mask =
+        (1ULL << (hash % bitsPerEntry)) | (1ULL << (hash2 % bitsPerEntry));
+    bloomTable[n] |= mask;
+  }
+
+  bool testHash(uint32_t hash) const {
+    uint32_t hash2 = hash >> bloomShift;
+    uint32_t n = (hash / bitsPerEntry) % bloomSize;
+    uint64_t mask =
+        (1ULL << (hash % bitsPerEntry)) | (1ULL << (hash2 % bitsPerEntry));
+    return (bloomTable[n] & mask) == mask;
+  }
+
+  static constexpr uint32_t log2ceil(uint32_t v) {
+    return v <= 1 ? 0 : 32 - countl_zero(v - 1);
+  }
+};
+
+class BloomFilterBuilder {
+public:
+  using HashFunc = BloomFilter::HashFunc;
+
+  BloomFilterBuilder() = default;
+
+  BloomFilterBuilder &setFalsePositiveRate(float rate) {
+    assert(rate > 0.0f && rate < 1.0f);
+    falsePositiveRate = rate;
+    return *this;
+  }
+
+  BloomFilterBuilder &setHashFunction(HashFunc func) {
+    hashFunc = std::move(func);
+    return *this;
+  }
+
+  BloomFilter build(const std::vector<std::string> &symbols) const {
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SahilPatidar wrote:

can try `StringRef` or Range?

https://github.com/llvm/llvm-project/pull/148410