[llvm] [memprof] Add Version2 of the indexed MemProf format (PR #89100)

[Kazu Hirata via llvm-commits]

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@@ -633,6 +633,96 @@ class FrameLookupTrait {
   }
 };
 
+// Trait for writing call stacks to the on-disk hash table.
+class CallStackWriterTrait {
+public:
+  using key_type = CallStackId;
+  using key_type_ref = CallStackId;
+
+  using data_type = llvm::SmallVector<FrameId>;
+  using data_type_ref = llvm::SmallVector<FrameId> &;
+
+  using hash_value_type = CallStackId;
+  using offset_type = uint64_t;
+
+  static hash_value_type ComputeHash(key_type_ref K) { return K; }
+
+  static std::pair<offset_type, offset_type>
+  EmitKeyDataLength(raw_ostream &Out, key_type_ref K, data_type_ref V) {
+    using namespace support;
+    endian::Writer LE(Out, llvm::endianness::little);
+    offset_type N = sizeof(K);
+    LE.write<offset_type>(N);
+    offset_type M = sizeof(CallStackId) * V.size();
+    LE.write<offset_type>(M);
+    return std::make_pair(N, M);
+  }
+
+  void EmitKey(raw_ostream &Out, key_type_ref K, offset_type /*Unused*/) {
+    using namespace support;
+    endian::Writer LE(Out, llvm::endianness::little);
+    LE.write<key_type>(K);
+  }
+
+  void EmitData(raw_ostream &Out, key_type_ref /*Unused*/, data_type_ref V,
+                offset_type /*Unused*/) {
+    using namespace support;
+    endian::Writer LE(Out, llvm::endianness::little);
+    // Emit the frames.  We do not explicitly emit the length of the vector
+    // because it can be inferred from the data length.
+    for (FrameId F : V)
+      LE.write<FrameId>(F);
+  }
+};
+
+// Trait for reading call stack mappings from the on-disk hash table.
+class CallStackLookupTrait {
+public:
+  using data_type = const llvm::SmallVector<FrameId>;
+  using internal_key_type = CallStackId;
+  using external_key_type = CallStackId;
+  using hash_value_type = CallStackId;
+  using offset_type = uint64_t;
+
+  static bool EqualKey(internal_key_type A, internal_key_type B) {
+    return A == B;
+  }
+  static uint64_t GetInternalKey(internal_key_type K) { return K; }
+  static uint64_t GetExternalKey(external_key_type K) { return K; }
+
+  hash_value_type ComputeHash(internal_key_type K) { return K; }
+
+  static std::pair<offset_type, offset_type>
+  ReadKeyDataLength(const unsigned char *&D) {
+    using namespace support;
+
+    offset_type KeyLen =
+        endian::readNext<offset_type, llvm::endianness::little>(D);
+    offset_type DataLen =
+        endian::readNext<offset_type, llvm::endianness::little>(D);
+    return std::make_pair(KeyLen, DataLen);
+  }
+
+  uint64_t ReadKey(const unsigned char *D, offset_type /*Unused*/) {
+    using namespace support;
+    return endian::readNext<external_key_type, llvm::endianness::little>(D);
+  }
+
+  data_type ReadData(uint64_t K, const unsigned char *D, offset_type Length) {
+    using namespace support;
+    llvm::SmallVector<FrameId> CS;
+    // Derive the number of frames from the data length.
+    uint64_t NumFrames = Length / sizeof(CallStackId);
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kazutakahirata wrote:

Thank you for catching this!  Fixed.

https://github.com/llvm/llvm-project/pull/89100