move the overall layout to the header

Author: nocchijiang

llvm/include/llvm/CGData/StableFunctionMapRecord.h

@@ -24,6 +24,26 @@
 
 namespace llvm {
 
+/// The structure of the serialized stable function map is as follows:
+/// - Number of unique function/module names
+/// - Total size of unique function/module names for opt-in skipping
+/// - Unique function/module names
+/// - Padding to align to 4 bytes
+/// - Number of StableFunctionEntries
+/// - Hashes of each StableFunctionEntry
+/// - Fixed-size fields for each StableFunctionEntry (the order is consistent
+///   with the hashes above):
+///   - FunctionNameId
+///   - ModuleNameId
+///   - InstCount
+///   - Relative offset to the beginning of IndexOperandHashes for this entry
+/// - Total size of variable-sized IndexOperandHashes for lazy-loading support
+/// - Variable-sized IndexOperandHashes for each StableFunctionEntry:
+///   - Number of IndexOperandHashes
+///   - Contents of each IndexOperandHashes
+///     - InstIndex
+///     - OpndIndex
+///     - OpndHash
 struct StableFunctionMapRecord {
   std::unique_ptr<StableFunctionMap> FunctionMap;
 

llvm/lib/CGData/StableFunctionMapRecord.cpp

@@ -104,18 +104,7 @@ void StableFunctionMapRecord::serialize(
       Writer.OS.tell() - NamesByteSizeOffset - sizeof(NamesByteSizeOffset);
   PatchItems.emplace_back(NamesByteSizeOffset, &NamesByteSize, 1);
 
-  // Write StableFunctionEntries. The structure is:
-  // - Number of StableFunctionEntries
-  // - Hashes of StableFunctionEntries
-  // - Fixed-size fields for each StableFunctionEntry
-  //   - FunctionNameId
-  //   - ModuleNameId
-  //   - InstCount
-  //   - Relative offset to IndexOperandHashes
-  // - Total size of variable-sized IndexOperandHashes for lazy-loading support
-  // - Variable-sized IndexOperandHashes for each StableFunctionEntry
-  //   - Number of IndexOperandHashes
-  //   - Contents of each IndexOperandHashes
+  // Write StableFunctionEntries whose pointers are sorted.
   auto FuncEntries = getStableFunctionEntries(*FunctionMap);
   Writer.write<uint32_t>(FuncEntries.size());
   for (const auto *FuncRef : FuncEntries)