[llvm-branch-commits] [llvm] [BOLT] Hash-based function matching (PR #95821)

[Amir Ayupov via llvm-branch-commits]

================
@@ -363,9 +364,27 @@ Error YAMLProfileReader::readProfile(BinaryContext &BC) {
     return Profile.Hash == static_cast<uint64_t>(BF.getHash());
   };
 
-  // We have to do 2 passes since LTO introduces an ambiguity in function
-  // names. The first pass assigns profiles that match 100% by name and
-  // by hash. The second pass allows name ambiguity for LTO private functions.
+  uint64_t MatchedWithExactName = 0;
+  uint64_t MatchedWithHash = 0;
+  uint64_t MatchedWithLTOCommonName = 0;
+
+  // Computes hash for binary functions.
+  if (opts::MatchingFunctionsWithHash) {
+    for (auto &[_, BF] : BC.getBinaryFunctions())
+      BF.computeHash(YamlBP.Header.IsDFSOrder, YamlBP.Header.HashFunction);
+  } else {
+    for (auto [YamlBF, BF] : llvm::zip_equal(YamlBP.Functions, ProfileBFs)) {
+      if (!BF)
+        continue;
+      BinaryFunction &Function = *BF;
+
+      if (!opts::IgnoreHash)
+        Function.computeHash(YamlBP.Header.IsDFSOrder,
+                             YamlBP.Header.HashFunction);
+    }
+  }
----------------
aaupov wrote:

```suggestion
  if (opts::MatchingFunctionsWithHash)
    for (auto &[_, BF] : BC.getBinaryFunctions())
      BF.computeHash(YamlBP.Header.IsDFSOrder, YamlBP.Header.HashFunction);
  else if (!opts::IgnoreHash)
    for (BinaryFunction *BF : ProfileBFs)
      BF->computeHash(YamlBP.Header.IsDFSOrder, YamlBP.Header.HashFunction);
```

https://github.com/llvm/llvm-project/pull/95821