[LLDB] Fix the 'default' switch case in GetCompatibleArchs()

[fixathon]

Summary

Moving the discussion of this issue that started in https://reviews.llvm.org/D113155 to here for clarity.

1. The 'default' switch case falls through to ArchSpec::Core_arm_arm64 due to the missing 'break', which seems wrong..

2. The following test is failing after #1 is corrected:

$ llvm-lit -sv llvm-project/lldb/test/API/functionalities/gdb_remote_client/TestPlatformMacOSX.py
..
AssertionError: 'host' != 'remote-ios'

Additionally, @clayborg discovered mismatch in cputype between qHostInfo and qProcessInfo.
However, even if that is corrected the test appears to be failing. GetCompatibleArchs() in PlatformDarwin.cpp receives ArchSpec::kCore_invalid
Tested on M1 hardware running MacOS 12.5

[fixathon]

This is an unfinished draft up for discussion.

[clayborg]

However, even if that is corrected the test appears to be failing. GetCompatibleArchs() in PlatformDarwin.cpp receives ArchSpec::kCore_invalid

Can you set a breakpoint and see why an invalid core is being passed into this function? This shouldn't be happening IMHO

lldb/test/API/functionalities/gdb_remote_client/TestPlatformMacOSX.py

22

I believe that Jonas stated in the other diff that this was intentional.

[JDevlieghere]

As mentioned in D113155 the difference in CPU type between qHostInfo and qProcessInfo is intentional.

[fixathon]

lldb/test/API/functionalities/gdb_remote_client/TestPlatformMacOSX.py

22

I will undo. This file is included here mostly for context as I moved the discussion into this separate new diff.

lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp

if (host_arch.GetCore() == ArchSpec::eCore_x86_64_x86_64h) {
     if (host_arch.IsExactMatch(host_arch64))
       archs.push_back(HostInfo::GetArchitecture(HostInfo::eArchKind32));
   }
 }
 
 static llvm::ArrayRef<const char *> GetCompatibleArchs(ArchSpec::Core core) {
   switch (core) {
   default:
-    [[fallthrough]];
+    break;
   case ArchSpec::eCore_arm_arm64e: {
     static const char *g_arm64e_compatible_archs[] = {
         "arm64e",    "arm64",    "armv7",    "armv7f",   "armv7k",   "armv7s",
         "armv7m",    "armv7em",  "armv6m",   "armv6",    "armv5",    "armv4",
         "arm",       "thumbv7",  "thumbv7f", "thumbv7k", "thumbv7s", "thumbv7m",
         "thumbv7em", "thumbv6m", "thumbv6",  "thumbv5",  "thumbv4t", "thumb",
     };
     return {g_arm64e_compatible_archs};

lldb/test/API/functionalities/gdb_remote_client/TestPlatformMacOSX.py

class MyResponder(MockGDBServerResponder):
             MockGDBServerResponder.__init__(self)
 
         def respond(self, packet):
             if packet == "qProcessInfo":
                 return self.qProcessInfo()
             return MockGDBServerResponder.respond(self, packet)
 
         def qHostInfo(self):
-            return "cputype:16777223;cpusubtype:2;ostype:%s;vendor:apple;os_version:10.15.4;maccatalyst_version:13.4;endian:little;ptrsize:8;" % self.host_ostype
+            return "cputype:16777228;cpusubtype:2;ostype:%s;vendor:apple;os_version:10.15.4;maccatalyst_version:13.4;endian:little;ptrsize:8;" % self.host_ostype
 
         def qProcessInfo(self):
             return "pid:a860;parent-pid:d2a0;real-uid:1f5;real-gid:14;effective-uid:1f5;effective-gid:14;cputype:100000c;cpusubtype:2;ptrsize:8;ostype:ios;vendor:apple;endian:little;"
 
         def vCont(self):
             return "vCont;"
 
     def platform_test(self, host, expected_triple, expected_platform):