[BOLT][NFC] Pass BF/BB hashes to BAT

Test Plan: NFC

Reviewers: dcci, rafaelauler, maksfb, ayermolo

Reviewed By: rafaelauler

Pull Request: #76906

Author: aaupov

bolt/include/bolt/Profile/BoltAddressTranslation.h

@@ -111,6 +111,9 @@ class BoltAddressTranslation {
   /// addresses when aggregating profile
   bool enabledFor(llvm::object::ELFObjectFileBase *InputFile) const;
 
+  /// Save function and basic block hashes used for metadata dump.
+  void saveMetadata(BinaryContext &BC);
+
 private:
   /// Helper to update \p Map by inserting one or more BAT entries reflecting
   /// \p BB for function located at \p FuncAddress. At least one entry will be
@@ -140,6 +143,9 @@ class BoltAddressTranslation {
 
   std::map<uint64_t, MapTy> Maps;
 
+  using BBHashMap = std::unordered_map<uint32_t, size_t>;
+  std::unordered_map<uint64_t, std::pair<size_t, BBHashMap>> FuncHashes;
+
   /// Links outlined cold bocks to their original function
   std::map<uint64_t, uint64_t> ColdPartSource;
 

bolt/lib/Profile/BoltAddressTranslation.cpp

@@ -424,5 +424,20 @@ bool BoltAddressTranslation::enabledFor(
   }
   return false;
 }
+
+void BoltAddressTranslation::saveMetadata(BinaryContext &BC) {
+  for (BinaryFunction &BF : llvm::make_second_range(BC.getBinaryFunctions())) {
+    // We don't need a translation table if the body of the function hasn't
+    // changed
+    if (BF.isIgnored() || (!BC.HasRelocations && !BF.isSimple()))
+      continue;
+    // Prepare function and block hashes
+    FuncHashes[BF.getAddress()].first = BF.computeHash();
+    BF.computeBlockHashes();
+    for (const BinaryBasicBlock &BB : BF)
+      FuncHashes[BF.getAddress()].second.emplace(BB.getInputOffset(),
+                                                 BB.getHash());
+  }
+}
 } // namespace bolt
 } // namespace llvm

bolt/lib/Rewrite/RewriteInstance.cpp

@@ -748,6 +748,10 @@ Error RewriteInstance::run() {
 
   processProfileData();
 
+  // Save input binary metadata if BAT section needs to be emitted
+  if (opts::EnableBAT)
+    BAT->saveMetadata(*BC);
+
   postProcessFunctions();
 
   processMetadataPostCFG();