[lldb] Add support for gdb-style 'x' packet (#124733)

See also
https://discourse.llvm.org/t/rfc-fixing-incompatibilties-of-the-x-packet-w-r-t-gdb/84288
and https://sourceware.org/pipermail/gdb/2025-January/051705.html

1 files changed, 9 insertions, 2 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
index 898d176..1118a76 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -218,7 +218,14 @@ public:
 
   bool GetpPacketSupported(lldb::tid_t tid);
 
-  bool GetxPacketSupported();
+  enum class xPacketState {
+    Unimplemented,
+    Prefixed, // Successful responses start with a 'b' character. This is the
+              // style used by GDB.
+    Bare,     // No prefix, packets starts with the memory being read. This is
+              // LLDB's original style.
+  };
+  xPacketState GetxPacketState();
 
   bool GetVAttachOrWaitSupported();
 
@@ -541,7 +548,6 @@ protected:
   LazyBool m_attach_or_wait_reply = eLazyBoolCalculate;
   LazyBool m_prepare_for_reg_writing_reply = eLazyBoolCalculate;
   LazyBool m_supports_p = eLazyBoolCalculate;
-  LazyBool m_supports_x = eLazyBoolCalculate;
   LazyBool m_avoid_g_packets = eLazyBoolCalculate;
   LazyBool m_supports_QSaveRegisterState = eLazyBoolCalculate;
   LazyBool m_supports_qXfer_auxv_read = eLazyBoolCalculate;
@@ -561,6 +567,7 @@ protected:
   LazyBool m_supports_memory_tagging = eLazyBoolCalculate;
   LazyBool m_supports_qSaveCore = eLazyBoolCalculate;
   LazyBool m_uses_native_signals = eLazyBoolCalculate;
+  std::optional<xPacketState> m_x_packet_state;
 
   bool m_supports_qProcessInfoPID : 1, m_supports_qfProcessInfo : 1,
       m_supports_qUserName : 1, m_supports_qGroupName : 1,