Completely avoid building Apple simulator on non-Darwin platforms.

[chaoren]

Summary

This is a resubmission of r252179, but correctly ignores the source
files for other platforms.

[zturner]

Isn't this going to have the same problem as before? If CMake finds a source file in the directory that is not added to one of the targets, it will give you an error. With this patch, on Linux or Windows PlatformAppleSimulator.cpp will be on disk, but not part of the lldbPluginPlatformMacOSX target, and as a result CMake will complain.

[chaoren]

LLVM_OPTIONAL_SOURCES should avoid that.

[chaoren]

It's not actually CMake complaining but the LLVM cmake scripts.

[zturner]

Ahh makes sense, I didn't know about that. I think a cleaner way to do this is to just add everything to PLUGIN_PLATFORM_MACOSX_SOURCES in the very first list(APPEND). Then just do this:

if (NOT CMAKE_SYSTEM_NAME MATCHES "Darwin")
    set(LLVM_OPTIONAL_SOURCES
        PlatformAppleSimulator.cpp
        PlatformiOSSimulator.cpp
    )
    list(REMOVE_ITEM PLUGIN_PLATFORM_MACOSX_SOURCES ${LLVM_OPTIONAL_SOURCES})
endif()

[chaoren]

I haven't seen anything else that uses LLVM_OPTIONAL_SOURCES, but it's conceivable that there might be items in the list already, and I would like to avoid doing anything to it besides just appending.

[zturner]

I find the code to be a fair bit harder to understand as a result, but I guess it's not the end of the world.

Searching the source of LLVM's CMake infrastructure, this variable exists solely to make LLVM not complain about missing files in the current directory, so I can't see any way that anything outside of the current directory's CMakeList.txt could have modified it intentionally. So I think it's safe, in the same way that the pattern for setting library dependencies is to write something like this:

set(LLVM_LINK_COMPONENTS
  Analysis
  AsmParser
  Core
  Support
  )

rather than appending. Anyway, up to you.

source/Initialization/SystemInitializerCommon.cpp

 #include "Plugins/ObjectFile/ELF/ObjectFileELF.h"
 #include "Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.h"
 #include "Plugins/OperatingSystem/Python/OperatingSystemPython.h"
 #include "Plugins/OperatingSystem/Go/OperatingSystemGo.h"
 #include "Plugins/Platform/Android/PlatformAndroid.h"
 #include "Plugins/Platform/FreeBSD/PlatformFreeBSD.h"
 #include "Plugins/Platform/Kalimba/PlatformKalimba.h"
 #include "Plugins/Platform/Linux/PlatformLinux.h"
-#include "Plugins/Platform/MacOSX/PlatformiOSSimulator.h"
 #include "Plugins/Platform/MacOSX/PlatformMacOSX.h"
 #include "Plugins/Platform/MacOSX/PlatformRemoteiOS.h"
 #include "Plugins/Platform/Windows/PlatformWindows.h"
 #include "Plugins/Process/gdb-remote/ProcessGDBRemoteLog.h"
 
 #if defined(__APPLE__)
+#include "Plugins/Platform/MacOSX/PlatformiOSSimulator.h"
 #include "Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.h"
 #include "Plugins/ObjectFile/Mach-O/ObjectFileMachO.h"
 #include "Plugins/Platform/MacOSX/PlatformDarwinKernel.h"
 #endif
 
 #if defined(__linux__)
 #include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
 #endif
#endif
     //----------------------------------------------------------------------
     // Apple/Darwin hosted plugins
     //----------------------------------------------------------------------
     DynamicLoaderMacOSXDYLD::Initialize();
     ObjectContainerUniversalMachO::Initialize();
 
     PlatformRemoteiOS::Initialize();
     PlatformMacOSX::Initialize();
-    PlatformiOSSimulator::Initialize();
 
 #if defined(__APPLE__)
+    PlatformiOSSimulator::Initialize();
     DynamicLoaderDarwinKernel::Initialize();
     PlatformDarwinKernel::Initialize();
     ObjectFileMachO::Initialize();
 #endif
 #if defined(__linux__)
     static ConstString g_linux_log_name("linux");
     ProcessPOSIXLog::Initialize(g_linux_log_name);
 #endif
SystemInitializerCommon::Terminate()
     platform_linux::PlatformLinux::Terminate();
     PlatformWindows::Terminate();
     PlatformKalimba::Terminate();
     platform_android::PlatformAndroid::Terminate();
     DynamicLoaderMacOSXDYLD::Terminate();
     ObjectContainerUniversalMachO::Terminate();
     PlatformMacOSX::Terminate();
     PlatformRemoteiOS::Terminate();
-    PlatformiOSSimulator::Terminate();
 
     ClangASTContext::Terminate();
     GoASTContext::Terminate();
 
     EmulateInstructionARM::Terminate();
     EmulateInstructionMIPS::Terminate();
     EmulateInstructionMIPS64::Terminate();
 
 #if defined(__APPLE__)
+    PlatformiOSSimulator::Terminate();
     DynamicLoaderDarwinKernel::Terminate();
     ObjectFileMachO::Terminate();
     PlatformDarwinKernel::Terminate();
 #endif
 
 #if defined(_MSC_VER)
     ProcessWindowsLog::Terminate();
 #endif
 
 #ifndef LLDB_DISABLE_PYTHON
     OperatingSystemPython::Terminate();
 #endif
     OperatingSystemGo::Terminate();
 
     Log::Terminate();
 }

source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp

 #include "lldb/Target/Thread.h"
 
 #include "AppleObjCRuntimeV2.h"
 #include "AppleObjCClassDescriptorV2.h"
 #include "AppleObjCTypeEncodingParser.h"
 #include "AppleObjCDeclVendor.h"
 #include "AppleObjCTrampolineHandler.h"
 
+#if defined(__APPLE__)
 #include "Plugins/Platform/MacOSX/PlatformiOSSimulator.h"
+#endif
 
 using namespace lldb;
 using namespace lldb_private;
 
 // 2 second timeout when running utility functions
 #define UTILITY_FUNCTION_TIMEOUT_USEC 2*1000*1000
 
 static const char *g_get_dynamic_class_info_name = "__lldb_apple_objc_v2_get_dynamic_class_info";
AppleObjCRuntimeV2::UpdateISAToDescriptorMapIfNeeded()
     }
 }
 
 void
 AppleObjCRuntimeV2::WarnIfNoClassesCached ()
 {
     if (m_noclasses_warning_emitted)
         return;
-    
+#if defined(__APPLE__)
     if (m_process &&
         m_process->GetTarget().GetPlatform() &&
         m_process->GetTarget().GetPlatform()->GetPluginName() == PlatformiOSSimulator::GetPluginNameStatic())
     {
         // the iOS simulator does not have the objc_opt_ro class table
         // so don't actually complain to the user
         m_noclasses_warning_emitted = true;
         return;
     }
-    
+#endif
     Debugger &debugger(GetProcess()->GetTarget().GetDebugger());
     
     if (debugger.GetAsyncOutputStream())
     {
         debugger.GetAsyncOutputStream()->PutCString("warning: could not load any Objective-C class information from the dyld shared cache. This will significantly reduce the quality of type information available.\n");
         m_noclasses_warning_emitted = true;
     }
 }

source/Plugins/Platform/MacOSX/CMakeLists.txt

 list(APPEND PLUGIN_PLATFORM_MACOSX_SOURCES
-  PlatformAppleSimulator.cpp
   PlatformDarwin.cpp
   PlatformDarwinKernel.cpp
-  PlatformiOSSimulator.cpp
   PlatformMacOSX.cpp
   PlatformRemoteiOS.cpp
   )
 
-if(CMAKE_SYSTEM_NAME MATCHES "Darwin")
-list(APPEND PLUGIN_PLATFORM_MACOSX_SOURCES
+list(APPEND PLUGIN_PLATFORM_MACOSX_DARWIN_ONLY_SOURCES
+  PlatformAppleSimulator.cpp
+  PlatformiOSSimulator.cpp
   PlatformiOSSimulatorCoreSimulatorSupport.mm
   )
+
+if(CMAKE_SYSTEM_NAME MATCHES "Darwin")
+  list(APPEND PLUGIN_PLATFORM_MACOSX_SOURCES
+    ${PLUGIN_PLATFORM_MACOSX_DARWIN_ONLY_SOURCES})
+else()
+  list(APPEND LLVM_OPTIONAL_SOURCES
+    ${PLUGIN_PLATFORM_MACOSX_DARWIN_ONLY_SOURCES})
 endif()
 
 add_lldb_library(lldbPluginPlatformMacOSX ${PLUGIN_PLATFORM_MACOSX_SOURCES})