[lldb] [llvm] [lldb][Windows] WoA HW Watchpoint support in LLDB (PR #108072)

[David Spickett via llvm-commits]

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@@ -492,23 +492,40 @@ NativeProcessWindows::OnDebugException(bool first_chance,
   }
   case DWORD(STATUS_BREAKPOINT):
   case STATUS_WX86_BREAKPOINT:
-    if (FindSoftwareBreakpoint(record.GetExceptionAddress())) {
-      LLDB_LOG(log, "Hit non-loader breakpoint at address {0:x}.",
-               record.GetExceptionAddress());
 
-      StopThread(record.GetThreadID(), StopReason::eStopReasonBreakpoint);
+    if (NativeThreadWindows *stop_thread =
+            GetThreadByID(record.GetThreadID())) {
+      auto &reg_ctx = stop_thread->GetRegisterContext();
+      const auto exception_addr = record.GetExceptionAddress();
+      const auto thread_id = record.GetThreadID();
 
-      if (NativeThreadWindows *stop_thread =
-              GetThreadByID(record.GetThreadID())) {
-        auto &register_context = stop_thread->GetRegisterContext();
-        uint32_t breakpoint_size = GetSoftwareBreakpointPCOffset();
+      if (FindSoftwareBreakpoint(exception_addr)) {
+        LLDB_LOG(log, "Hit non-loader breakpoint at address {0:x}.",
+                 exception_addr);
         // The current PC is AFTER the BP opcode, on all architectures.
-        uint64_t pc = register_context.GetPC() - breakpoint_size;
-        register_context.SetPC(pc);
+        reg_ctx.SetPC(reg_ctx.GetPC() - GetSoftwareBreakpointPCOffset());
+        StopThread(thread_id, StopReason::eStopReasonBreakpoint);
+        SetState(eStateStopped, true);
+        return ExceptionResult::MaskException;
+      } else {
+        const std::vector<ULONG_PTR> &args = record.GetExceptionArguments();
+        // Check that the ExceptionInformation array of EXCEPTION_RECORD
+        // contains at least two elements: the first is a read-write flag
+        // indicating the type of data access operation (read or write) while
+        // the second contains the virtual address of the accessed data.
+        if (args.size() >= 2) {
+          uint32_t hw_id = LLDB_INVALID_INDEX32;
+          reg_ctx.GetWatchpointHitIndex(hw_id, args[1]);
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DavidSpickett wrote:

Ideally every error path returns LLDB_INVALID_INDEX32 but you should check that the returned Status is not a failure as well, just in case.

https://github.com/llvm/llvm-project/pull/108072