[BOLT][NFC] Simplify postProcessJumpTables

[rafauler]

LGTM

bolt/lib/Core/BinaryFunction.cpp

void BinaryFunction::postProcessJumpTables() {
   for (auto &JTI : JumpTables) {
     JumpTable &JT = *JTI.second;
     if (JT.Type == JumpTable::JTT_PIC && opts::JumpTables == JTS_BASIC) {
       opts::JumpTables = JTS_MOVE;
       outs() << "BOLT-INFO: forcing -jump-tables=move as PIC jump table was "
                 "detected in function "
              << *this << '\n';
     }
-    if (JT.Entries.empty()) {
-      bool HasOneParent = (JT.Parents.size() == 1);
-      for (unsigned I = 0; I < JT.EntriesAsAddress.size(); ++I) {
-        uint64_t EntryAddress = JT.EntriesAsAddress[I];
-        // builtin_unreachable does not belong to any function
-        // Need to handle separately
-        bool IsBuiltIn = false;
-        for (BinaryFunction *Parent : JT.Parents) {
-          if (EntryAddress == Parent->getAddress() + Parent->getSize()) {
-            IsBuiltIn = true;
-            // Specify second parameter as true to accept builtin_unreachable
-            MCSymbol *Label = getOrCreateLocalLabel(EntryAddress, true);
-            JT.Entries.push_back(Label);
-            break;
-          }
-        }
-        if (IsBuiltIn)
-          continue;
-        // Create local label for targets cannot be reached by other fragments
-        // Otherwise, secondary entry point to target function
-        BinaryFunction *TargetBF =
-            BC.getBinaryFunctionContainingAddress(EntryAddress);
-        if (TargetBF->getAddress() != EntryAddress) {
-          MCSymbol *Label =
-              (HasOneParent && TargetBF == this)
-                  ? getOrCreateLocalLabel(JT.EntriesAsAddress[I], true)
-                  : TargetBF->addEntryPointAtOffset(EntryAddress -
-                                                    TargetBF->getAddress());
-          JT.Entries.push_back(Label);
-        }
-      }
-    }
+    const uint64_t BDSize =
+        BC.getBinaryDataAtAddress(JT.getAddress())->getSize();
+    if (!BDSize) {
+      BC.setBinaryDataSize(JT.getAddress(), JT.getSize());
+    } else {
+      assert(BDSize >= JT.getSize() &&
+             "jump table cannot be larger than the containing object");
+    }
+    if (!JT.Entries.empty())
+      continue;
+
+    for (uint64_t EntryAddress : JT.EntriesAsAddress) {
+      bool IsBuiltinUnreachable =
+          llvm::any_of(JT.Parents, [&](const BinaryFunction *Parent) {
+            return EntryAddress == Parent->getAddress() + Parent->getSize();
+          });
+      if (IsBuiltinUnreachable) {
+      }
+      if (uint64_t Offset = EntryAddress - TargetBF->getAddress()) {
+        MCSymbol *Label = (HasOneParent && TargetBF == this)
+                              ? getOrCreateLocalLabel(EntryAddress, true)
+                              : TargetBF->addEntryPointAtOffset(Offset);
 
-    const uint64_t BDSize =
-        BC.getBinaryDataAtAddress(JT.getAddress())->getSize();
-    if (!BDSize) {
-      BC.setBinaryDataSize(JT.getAddress(), JT.getSize());
-    } else {
-      assert(BDSize >= JT.getSize() &&
-             "jump table cannot be larger than the containing object");
-    }
-  }
-
   // Add TakenBranches from JumpTables.
   //
   // We want to do it after initial processing since we don't know jump tables'
   // boundaries until we process them all.
   for (auto &JTSite : JTSites) {
     const uint64_t JTSiteOffset = JTSite.first;
     const uint64_t JTAddress = JTSite.second;
     const JumpTable *JT = getJumpTableContainingAddress(JTAddress);