[llvm] [PseudoProbe] Extend to skip instrumenting probe into the dests of invoke (PR #79919)

[via llvm-commits]

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@@ -173,20 +173,49 @@ SampleProfileProber::SampleProfileProber(Function &Func,
   BlockProbeIds.clear();
   CallProbeIds.clear();
   LastProbeId = (uint32_t)PseudoProbeReservedId::Last;
-  computeProbeIdForBlocks();
+
+  DenseSet<BasicBlock *> InvokeNormalDests;
+  findInvokeNormalDests(InvokeNormalDests);
+  DenseSet<BasicBlock *> KnownColdBlocks;
+  computeEHOnlyBlocks(*F, KnownColdBlocks);
+
+  computeProbeIdForBlocks(InvokeNormalDests, KnownColdBlocks);
   computeProbeIdForCallsites();
-  computeCFGHash();
+  computeCFGHash(InvokeNormalDests, KnownColdBlocks);
+}
+
+void SampleProfileProber::findInvokeNormalDests(
+    DenseSet<BasicBlock *> &InvokeNormalDests) {
+  for (auto &BB : *F) {
+    auto *TI = BB.getTerminator();
+    if (auto *II = dyn_cast<InvokeInst>(TI))
+      InvokeNormalDests.insert(II->getNormalDest());
+  }
 }
 
 // Compute Hash value for the CFG: the lower 32 bits are CRC32 of the index
 // value of each BB in the CFG. The higher 32 bits record the number of edges
 // preceded by the number of indirect calls.
 // This is derived from FuncPGOInstrumentation<Edge, BBInfo>::computeCFGHash().
-void SampleProfileProber::computeCFGHash() {
+void SampleProfileProber::computeCFGHash(
+    const DenseSet<BasicBlock *> &InvokeNormalDests,
+    const DenseSet<BasicBlock *> &KnownColdBlocks) {
   std::vector<uint8_t> Indexes;
   JamCRC JC;
   for (auto &BB : *F) {
-    for (BasicBlock *Succ : successors(&BB)) {
+    // Skip the EH flow blocks.
+    if (InvokeNormalDests.contains(&BB) || KnownColdBlocks.contains(&BB))
+      continue;
+
+    // Find the original successors by skipping the EH flow succs.
+    auto *BBPtr = &BB;
+    auto *TI = BBPtr->getTerminator();
+    while (auto *II = dyn_cast<InvokeInst>(TI)) {
+      BBPtr = II->getNormalDest();
+      TI = BBPtr->getTerminator();
+    }
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WenleiHe wrote:

I see. So the point is if we simply ignore all flows from and into `BlocksToIgnore`, some original flow before call->invoke conversion can be cut off and missed, which again causes discrepancy. To avoid such discrepancy, we want to find out such original flow and consider it in hash computation, is that correct? 

If that's the case, comments needs to be updated. 

Should we also exclude zero block Id successors anyways? or assert the successors all have non-zero block Id.

https://github.com/llvm/llvm-project/pull/79919