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

[shaw young via llvm-branch-commits]

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@@ -374,15 +393,34 @@ Error YAMLProfileReader::readProfile(BinaryContext &BC) {
     // the profile.
     Function.setExecutionCount(BinaryFunction::COUNT_NO_PROFILE);
 
-    // Recompute hash once per function.
-    if (!opts::IgnoreHash)
-      Function.computeHash(YamlBP.Header.IsDFSOrder,
-                           YamlBP.Header.HashFunction);
-
-    if (profileMatches(YamlBF, Function))
+    if (profileMatches(YamlBF, Function)) {
       matchProfileToFunction(YamlBF, Function);
+      ++MatchedWithExactName;
+    }
   }
 
+  // Uses the strict hash of profiled and binary functions to match functions
+  // that are not matched by name or common name.
+  if (opts::MatchingFunctionsWithHash) {
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shawbyoung wrote:

In BOLT, a strict hash captures a binary function's block order as well as each blocks' instructions & opcodes. So, the goal of this PR is to recover block-identical functions that have been simply been renamed.

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