[llvm] [MemProf] Avoid incorrect ICP symtab canonicalization (PR #115419)

[Snehasish Kumar via llvm-commits]

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@@ -4143,7 +4143,17 @@ bool MemProfContextDisambiguation::initializeIndirectCallPromotionInfo(
     Module &M) {
   ICallAnalysis = std::make_unique<ICallPromotionAnalysis>();
   Symtab = std::make_unique<InstrProfSymtab>();
-  if (Error E = Symtab->create(M, /*InLTO=*/true)) {
+  // Don't add canonical names, to avoid multiple functions to the symtab
+  // when they both have the same root name with "." suffixes stripped.
+  // If we pick the wrong one then this could lead to incorrect ICP and calling
+  // a memprof clone that we don't actually create (resulting in linker unsats).
+  // What this means is that the GUID of the function (or its PGOFuncName
+  // metadata) *must* match that in the VP metadata to allow promotion.
+  // In practice this should not be a limitation, since local functions should
+  // have PGOFuncName metadata and global function names shouldn't need any
+  // special handling (they should not get the ".llvm.*" suffix that the
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snehasish wrote:

Parenthesis not closed?

https://github.com/llvm/llvm-project/pull/115419