[llvm] [memprof] Dump call site matching information (PR #125130)

[Teresa Johnson via llvm-commits]

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@@ -1201,15 +1203,22 @@ readMemprof(Module &M, Function &F, IndexedInstrProfReader *MemProfReader,
       // instruction's leaf location in the callsites map and not the allocation
       // map.
       assert(CallSitesIter != LocHashToCallSites.end());
-      for (auto CallStackIdx : CallSitesIter->second) {
+      for (auto &[ProfileCallStack, Idx] : CallSitesIter->second) {
         // If we found and thus matched all frames on the call, create and
         // attach call stack metadata.
-        if (stackFrameIncludesInlinedCallStack(CallStackIdx,
+        if (stackFrameIncludesInlinedCallStack(ProfileCallStack.drop_front(Idx),
                                                InlinedCallStack)) {
           NumOfMemProfMatchedCallSites++;
           addCallsiteMetadata(I, InlinedCallStack, Ctx);
           // Only need to find one with a matching call stack and add a single
           // callsite metadata.
+
+          // Dump call site matching information upon request.
+          if (ClPrintMemProfMatchInfo) {
+            uint64_t FullStackId = computeFullStackId(ProfileCallStack);
+            errs() << "MemProf callsite " << FullStackId << " " << Idx << " "
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teresajohnson wrote:

Maybe include a bit more info in the message about the latter 2 numbers being printed.

https://github.com/llvm/llvm-project/pull/125130