[llvm] [BOLT] Add validation for direct call/branch targets, bypassing invalid functions (PR #165406)

[Maksim Panchenko via llvm-commits]

================
@@ -1902,6 +1910,71 @@ bool BinaryFunction::scanExternalRefs() {
   return Success;
 }
 
+bool BinaryFunction::validateExternalBranch(uint64_t TargetAddress) {
+  if (!isSimple())
+    return true;
+
+  BinaryFunction *TargetFunction =
+      BC.getBinaryFunctionContainingAddress(TargetAddress);
+
+  bool IsValid = true;
+
+  if (TargetFunction) {
+    const uint64_t TargetOffset = TargetAddress - TargetFunction->getAddress();
+    // Skip empty functions and out-of-bounds offsets,
+    // as they may not be disassembled.
+    if (!TargetOffset || (TargetOffset > TargetFunction->getSize()))
+      return true;
+
+    if (TargetFunction->CurrentState == State::Disassembled &&
+        (!TargetFunction->getInstructionAtOffset(TargetOffset) ||
+         getSizeOfDataInCodeAt(TargetOffset)))
+      IsValid = false;
+  } else {
+    if (!BC.getSectionForAddress(TargetAddress))
+      IsValid = false;
+  }
+
+  if (!IsValid) {
+    setIgnored();
+    BC.errs() << "BOLT-WARNING: corrupted control flow detected in function "
+              << *this
+              << ", an external branch/call targets an invalid instruction "
+              << "at address 0x" << Twine::utohexstr(TargetAddress) << "\n";
+    return false;
+  }
+
+  return true;
+}
+
+bool BinaryFunction::validateInternalBranches() {
+  if (!isSimple())
----------------
maksfb wrote:

```suggestion
  if (!isSimple() || TrapsOnEntry)
```

https://github.com/llvm/llvm-project/pull/165406