[LLDB] [Windows] Add missing ifdefs to fix building for non-x86 architectures

[mstorsjo]

Summary

While debugging on those architectures might not be supported yet, the generic code should still be buildable. This file accesses x86 specific fields in the CONTEXT struct.

[compnerd]

What do you think of adding some sort of notification that hardware breakpoints are currently unsupported and that we are falling back to software breakpoints for the #else case?

lldb/source/Plugins/Process/Windows/Common/RegisterContextWindows.cpp

87

Should this line not also include || defined(__aarch64__) || defined(_M_ARM64)?

[mstorsjo]

In D67911#1679333, @compnerd wrote:

What do you think of adding some sort of notification that hardware breakpoints are currently unsupported and that we are falling back to software breakpoints for the #else case?

I guess it could make sense. What kind of notification do you have in mind?

lldb/source/Plugins/Process/Windows/Common/RegisterContextWindows.cpp

87

I guess it should. Or this might be one of the few places where checking for just _WIN64 might be easiest?

[compnerd]

I think that printf is quite an amazing notification :-)

lldb/source/Plugins/Process/Windows/Common/RegisterContextWindows.cpp

87

Yeah, I think that _WIN64 is probably the easiest thing indeed.

[mstorsjo]

In D67911#1679696, @compnerd wrote:

I think that printf is quite an amazing notification :-)

Ok, I'll make it an LLDB_LOG then, as I'd presume using raw printfs isn't really allowed :-)

[mstorsjo]

Added a log message, changed an x86_64 ifdef into _WIN64.

lldb/source/Plugins/Process/Windows/Common/RegisterContextWindows.cpp

bool RegisterContextWindows::AddHardwareBreakpoint(uint32_t slot,
                                                    bool write) {
   if (slot >= NUM_HARDWARE_BREAKPOINT_SLOTS)
     return false;
 
   switch (size) {
   case 1:
   case 2:
   case 4:
-#if defined(__x86_64__) || defined(_M_AMD64)
+#if defined(_WIN64)
   case 8:
 #endif
     break;
   default:
     return false;
   }
 
   if (!CacheAllRegisterValues())
     return false;
 
+#if defined(__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_AMD64)
   unsigned shift = 2 * slot;
   m_context.Dr7 |= 1ULL << shift;
 
   (&m_context.Dr0)[slot] = address;
 
   shift = 18 + 4 * slot;
   m_context.Dr7 &= ~(3ULL << shift);
   m_context.Dr7 |= (size == 8 ? 2ULL : size - 1) << shift;
 
   shift = 16 + 4 * slot;
   m_context.Dr7 &= ~(3ULL << shift);
   m_context.Dr7 |= (read ? 3ULL : (write ? 1ULL : 0)) << shift;
 
   return ApplyAllRegisterValues();
+
+#else
+  LLDB_LOG(log, "hardware breakpoints not currently supported on this arch");
+  return false;
+#endif
 }
 
 bool RegisterContextWindows::RemoveHardwareBreakpoint(uint32_t slot) {
   if (slot >= NUM_HARDWARE_BREAKPOINT_SLOTS)
     return false;
 
   if (!CacheAllRegisterValues())
     return false;
 
+#if defined(__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_AMD64)
   unsigned shift = 2 * slot;
   m_context.Dr7 &= ~(1ULL << shift);
 
   return ApplyAllRegisterValues();
+#else
+  return false;
+#endif
 }
 
 uint32_t RegisterContextWindows::GetTriggeredHardwareBreakpointSlotId() {
   if (!CacheAllRegisterValues())
     return LLDB_INVALID_INDEX32;
 
+#if defined(__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_AMD64)
   for (unsigned i = 0UL; i < NUM_HARDWARE_BREAKPOINT_SLOTS; i++)
     if (m_context.Dr6 & (1ULL << i))
       return i;
+#endif
 
   return LLDB_INVALID_INDEX32;
 }
 
 bool RegisterContextWindows::CacheAllRegisterValues() {
   Log *log = ProcessWindowsLog::GetLogIfAny(WINDOWS_LOG_REGISTERS);
   if (!m_context_stale)
     return true;