[llvm] [BOLT] Set call to continuation count in pre-aggregated profile (PR #109486)

[Maksim Panchenko via llvm-commits]

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@@ -774,42 +774,86 @@ bool DataAggregator::doInterBranch(BinaryFunction *FromFunc,
 }
 
 bool DataAggregator::doBranch(uint64_t From, uint64_t To, uint64_t Count,
-                              uint64_t Mispreds) {
-  bool IsReturn = false;
-  auto handleAddress = [&](uint64_t &Addr, bool IsFrom) -> BinaryFunction * {
-    if (BinaryFunction *Func = getBinaryFunctionContainingAddress(Addr)) {
-      Addr -= Func->getAddress();
-      if (IsFrom) {
-        auto checkReturn = [&](auto MaybeInst) {
-          IsReturn = MaybeInst && BC->MIB->isReturn(*MaybeInst);
-        };
-        if (Func->hasInstructions())
-          checkReturn(Func->getInstructionAtOffset(Addr));
-        else
-          checkReturn(Func->disassembleInstructionAtOffset(Addr));
-      }
+                              uint64_t Mispreds, bool IsPreagg) {
+  // Returns whether \p Offset in \p Func contains a return instruction.
+  auto checkReturn = [&](const BinaryFunction &Func, const uint64_t Offset) {
+    auto isReturn = [&](auto MI) { return MI && BC->MIB->isReturn(*MI); };
+    return Func.hasInstructions()
+               ? isReturn(Func.getInstructionAtOffset(Offset))
+               : isReturn(Func.disassembleInstructionAtOffset(Offset));
+  };
 
-      if (BAT)
-        Addr = BAT->translate(Func->getAddress(), Addr, IsFrom);
+  // Returns whether \p Offset in \p Func corresponds to a call continuation
+  // fallthrough block.
+  auto checkCallCont = [&](BinaryFunction &Func, const uint64_t Offset) {
+    // Note the use of MCInstrAnalysis: no call continuation for a tail call.
+    auto isCall = [&](auto MI) { return MI && BC->MIA->isCall(*MI); };
+
+    // No call continuation at a function start.
+    if (!Offset)
+      return false;
+
+    // FIXME: support BAT case where the function might be in empty state
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maksfb wrote:

Perhaps we should add secondary entry point and EH info to BAT then. It's important enough from CFG point of view.

https://github.com/llvm/llvm-project/pull/109486