[PATCH] D132495: [BOLT] Verify externally referenced blocks against jump table targets

[Amir Ayupov via Phabricator via llvm-commits]

Amir updated this revision to Diff 455794.
Amir added a comment.

Mark as non-simple


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D132495/new/

https://reviews.llvm.org/D132495

Files:
  bolt/lib/Core/BinaryFunction.cpp


Index: bolt/lib/Core/BinaryFunction.cpp
===================================================================
--- bolt/lib/Core/BinaryFunction.cpp
+++ bolt/lib/Core/BinaryFunction.cpp
@@ -1860,6 +1860,40 @@
   if (HasFixedIndirectBranch)
     return false;
 
+  // Validate that all data references to function offsets are claimed by
+  // recognized jump tables. Register externally referenced blocks as entry
+  // points.
+  if (!opts::StrictMode && hasInternalReference()) {
+    SmallPtrSet<MCSymbol *, 4> JTTargets;
+    for (const JumpTable *JT : llvm::make_second_range(JumpTables))
+      JTTargets.insert(JT->Entries.begin(), JT->Entries.end());
+
+    bool UnclaimedReference = false;
+    for (uint64_t Destination : ExternallyReferencedOffsets) {
+      // Ignore __builtin_unreachable().
+      if (Destination == getSize())
+        continue;
+
+      if (BinaryBasicBlock *BB = getBasicBlockAtOffset(Destination)) {
+        bool Found = JTTargets.contains(BB->getLabel());
+        if (Found)
+          continue;
+
+        if (opts::Verbosity >= 1) {
+          outs() << "BOLT-WARNING: unclaimed data to code reference (possibly "
+                 << "an unrecognized jump table entry) to " << BB->getName()
+                 << " in " << *this << ".\n";
+        }
+      } else if (opts::Verbosity >= 1) {
+        outs() << "BOLT-WARNING: unknown data to code reference to offset "
+               << Twine::utohexstr(Destination) << " in " << *this << ".\n";
+      }
+      UnclaimedReference = true;
+    }
+    if (UnclaimedReference)
+      return false;
+  }
+
   if (HasUnknownControlFlow && !BC.HasRelocations)
     return false;
 


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