[Lldb-commits] [lldb] [llvm] [lldb][Process/FreeBSDKernel] Print unread message buffer on start (PR #178027)

[via lldb-commits]

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@@ -234,6 +245,155 @@ lldb::addr_t ProcessFreeBSDKernel::FindSymbol(const char *name) {
   return sym ? sym->GetLoadAddress(&GetTarget()) : LLDB_INVALID_ADDRESS;
 }
 
+void ProcessFreeBSDKernel::PrintUnreadMessage() {
+  Target &target = GetTarget();
+  Debugger &debugger = target.GetDebugger();
+
+  if (!debugger.GetCommandInterpreter().IsInteractive())
+    return;
+
+  Status error;
+
+  // Find msgbufp symbol (pointer to message buffer)
+  lldb::addr_t msgbufp_addr = FindSymbol("msgbufp");
+  if (msgbufp_addr == LLDB_INVALID_ADDRESS)
+    return;
+
+  // Read the pointer value
+  lldb::addr_t msgbufp = ReadPointerFromMemory(msgbufp_addr, error);
+  if (!error.Success() || msgbufp == LLDB_INVALID_ADDRESS)
+    return;
+
+  // Get the type information for struct msgbuf from DWARF
+  TypeQuery query("msgbuf");
+  TypeResults results;
+  target.GetImages().FindTypes(nullptr, query, results);
+
+  uint64_t offset_msg_ptr = 0;
+  uint64_t offset_msg_size = 0;
+  uint64_t offset_msg_wseq = 0;
+  uint64_t offset_msg_rseq = 0;
+
+  if (results.GetTypeMap().GetSize() > 0) {
+    // Found type info - use it to get field offsets
+    CompilerType msgbuf_type =
+        results.GetTypeMap().GetTypeAtIndex(0)->GetForwardCompilerType();
+
+    uint32_t num_fields = msgbuf_type.GetNumFields();
+    int field_found = 0;
+    for (uint32_t i = 0; i < num_fields; i++) {
+      std::string field_name;
+      uint64_t field_offset = 0;
+      uint32_t field_bitfield_bit_size = 0;
+      bool field_is_bitfield = false;
+
+      msgbuf_type.GetFieldAtIndex(i, field_name, &field_offset,
+                                  &field_bitfield_bit_size, &field_is_bitfield);
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aokblast wrote:

You can set these two fields to nullptr since they are actually not used.

https://github.com/llvm/llvm-project/pull/178027